june 2004 Gasification Archive

For more information to help people develop better stoves for cooking with biomass fuels in developing regions, please see our web site: http://www.bioenergylists.org

From hotspringfreak at HOTMAIL.COM Tue Jun 1 01:38:27 2004
From: hotspringfreak at HOTMAIL.COM (Chris Smith)
Date: Tue Aug 10 18:31:12 2004
Subject: White LED Lamp
Message-ID: <TUE.1.JUN.2004.013827.0400.HOTSPRINGFREAK@HOTMAIL.COM>

2nd try sending this - apologizing for any duplication:

Found increasing cheaper all the time, are USB powered (5 VDC)
flexible "snakelights" for laptops. But putting a USB connector on a stove
with a TEG? Where do I get one of those? Here's one snakelight with 8
LED's!

http://www.iogear.com/main.php?loc=product&product_id=517

- Chris Smith

From snienhuys at SNV.ORG.NP Tue Jun 1 01:38:49 2004
From: snienhuys at SNV.ORG.NP (Sjoerd Nienhuys)
Date: Tue Aug 10 18:31:12 2004
Subject: Jmla Stove
In-Reply-To: <20040528213905.66910.qmail@web41601.mail.yahoo.com>
Message-ID: <TUE.1.JUN.2004.112349.0545.SNIENHUYS@SNV.ORG.NP>

Mountain stovers,

RE: [STOVES] Jmla Stove

Developing stoves in high altitudes and in very low-income areas have a
series of complex and interacting factors to consider.

1. One of them is firewood efficiency and the efforts of Kanchan Rai are
recommendable. Currently we are trying to incorporate several new
components to the simple metallic box stove such as a 'Rocket Mouthpiece'
attachment, an inner reflection/insulation shield and a sunken pot solution
to optimise heat transfer. Optional features to the basic improved metal
box stove are the 'Roti-maker' designed as a side door, and optional water
heater. Getting the people to minimise wood sections to maximal 4cm or 1.5"
probably requires major explanations and convincing. The study is ongoing
and I will report the results.

2. The other one is transport, the stoves need to be light-weight keeping
material weights low and allow either airplane or backpack transport. Our
development programme has no consumer subsidy and to develop a sustainable
situation durability of the stove should be combined with light weight. New
metals available in Nepal are being explored. Inox materials are not only
more resistant than mild steel, but they also look good, adding to the
prestige of the new stove designs.

3. The stove needs to be assembled locally without the need of welding
equipment. There is seldom electric power in most high altitudes that can
support welding. The thickest sheet steel that is pliable by hand tools is
the 1.2mm or 1.3mm or 18 gauge mild steel sheet. If a thicker top plate is
used (not advisable because of weight), it needs to be assembled locally to
build the stove. With local assembling local stove makers need to be
trained so they can maintain the stoves or replace parts.

3. The stoves need to be low-cost so use of local materials should be
optimised. Currently we are looking at further developing the table type
mud-stove of Jomsom/Mustang into a J-type stove, increasing its efficiency.
For a picture and drawing of the stove promoted by ACAP, see my Jomsom
mission report at www.icimod.org/snv.

4. With improving the fuel wood efficiency the yellow flames that other wise
bilge out from under the cooking pot disappear. As indicated in former
messages that causes a problem for the villagers as there is no electricity,
and at best some yellow flames from a kerosene or oil burning wick. One
solution is the commercial introduction of the WLED lamps (TUKIMARU=
kerosene killer) which now is available at the cost of Euro 2 for one WLED
with battery and mini-panel. It is unlikely that the villager will use any
improved stove when there is no more light in the pitch-black,
smoked-through and soot-walled, non-windowed kitchen rooms. The chickens at
these high altitudes are very meagre and certainly would not produce much
oil. Villagers are very reluctant to burn edible oils. See also the
chicken disaster mentioned in my Jomsom report.

5. As an alternative I had in an early stage proposed to place a container
with dry biomass over the second cooking hole in the stove. A bit like the
idea of Dean Still. Only the first hole will than be used for cooking with
light. With a better stove the cooking will go faster. The hot flue gasses
rising from the second hole will gasify the biomass and the gas can be
conducted to the top, to a common biogas lamp. The biomass container can
be supported in its gasifying action by an oil or kerosene drip. Because of
similar suggestions in earlier discussions, we will take up this issue again
and finance a line of research. The potential advantage of the idea is that
the gasified, charred biomass from the gas box can be used the next day in
fast starting the stove with minimal smoke generation.

6. For the cold areas (over 3000m) the stove has a room heating function for
the rich families. Room heating is only efficient when the heat does not
immediately disappear through poorly insulated walls or open windows and
roof holes. See my report on Pakistan Buchari stoves from stoves website
http://crest.org/discussiongroups/resources/stoves/gal2003.htm. and my
reports on Roof Hatch Window and Thermal Insulation from
www.icimod.org/snv.
Currently the SNV together with WWF are developing and soon implementing a
demonstration project on thermal insulation for high altitudes in Solokhumbu
region. The results will be applicable in all high altitudes.

7. Rajendra Adhikari correctly mentioned that in the high Mustang or Tibet
(and lower Jomsom) no or very little firewood or biomass is available.
Solutions at these high altitudes must be found in a combination of thermal
insulation of houses and the use of passive solar energy. Solar radiation
coming in through clean windows can keep the house warm. Better windows are
for Mustang a new technology and will be in substantial conflict with the
local vernacular architecture for which the area is renown. If I find a
suitable local (Nepali) partner organisation, we can develop a demonstration
project in Mustang, including stoves, thermal insulation and passive solar
energy that blends in with the local architecture.

8. The chimney design, smoke evacuation and (fresh) air ventilation requires
both good designs, rethinking of the use of windows but most and for all
education of the people. Traditional houses have no windows because these
allow cold air in and warm air to go out. Glass was until recently
unavailable. UV resistant greenhouse foil (Silpaulin in Nepal) is possible
and clever people use the plastic in winters to make double windows. An
improved chimney hood is presented in figure 30 of the same Pakistan report.
With strong winds, or in strong wind areas the use of a chimney damper valve
is essential. In Jomsom and higher the wind increases every afternoon to
storm levels. Without a damper that will suck all the air out of the house.

9. Development in these issues is sometimes a slow process of formulating
acceptable proposals for financing (luckily we have some funds) after an
identification phase; proposals that are also acceptable to local government
organisations. We need to compare theoretic laboratory results with field
experiences and incorporate the observations of the end-users, the women who
do the cooking; adjust the designs to different geographical areas, house
designs and cost of biomass; assure that several translation switches are
made from academic and English into simple local languages, make drawings
and photo's and simplified text manuals, instructions and demonstrations;
organise community based workshop and exchange visits between different
areas for dissemination. etc etc.

We are working on the various stove problems for Dolpa (comparable to
Jumla/Humla) and Solokhumbu, and I find a lot of support and good ideas from
the stove discussion list.

Sjoerd Nienhuys
Senior Renewable Energy Advisor
SNV/N, Netherlands Development Organisation
P.O. Box 1966, Kathmandu, Nepal
Telephone: ++997-1-5523444
snienhuys@snv.org.np

---------------------------------------------------------
on Friday 28 May 2004 Kanchan wrote:

>Thanks for taking time for writing and sharing experience from Mustang.
>The place are similar in terms of altitude and need of stove for cooking
and room >heating.
>But economically people are far back in Humla and Jumla (western Nepal).
> I guess that the people in mustang is economically in good condition.
>What kind of stove you saw in Mustang? Do they use metal stove?
>
In mustang also there are many poor families like in Jumla, specially the
lower caste in that specific society. The rich ones have fixed type clay
stove, which they use during warm days; and also a portable metallic stove
which they use generally during cold period of the year to cook the food and
to warm the room. The rich family runs the metallic cookstoves 24
hours a day, because he has to survive in the biting cold. Specially in
Upper Mustang adjacent to Tibet you could roughly classify a family as a
rich one, if he has: (1) a metallic stove in the room and (2) collection of
fire wood spread over the top of the flat roof of the house.

The poor ones have no metallic stove, and live with the age old clay or
stone type fire place. But the biting reality is that both the rich and
the poor must have some sort of cookstove to live on this earth. In Jumla
or in Solokhumbu in Nepal, Thank God, at least firewood/pine wood is still
available either free of cost or at a very low price. But in Upper Mustang
firewood is a very costly item, sometimes unaffordable to the common poor.
The poor houses do not have any firewood collected over the top of the roof.

Ordinary chimney with fixed exhaust position will not work properly in high
altitude areas with strong blowing wind and wind often changing the
blowing direction. If the exhaust of the chimney is against the wind , smoke
will blow back to the fireplace. If it is in the same direction, extra draft
will be created inside the chimney leading to the unnecessary burning of
the costly biomass. How have you designed the chimney to cope with this
problem?

R. B. Adhikari
rbadhi@yahoo.com

---------------------------------
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From elk at WANANCHI.COM Tue Jun 1 02:10:18 2004
From: elk at WANANCHI.COM (Elsen Karstad)
Date: Tue Aug 10 18:31:12 2004
Subject: TEGs & LEDs
Message-ID: <TUE.1.JUN.2004.091018.0300.ELK@WANANCHI.COM>

I've produced up to 4.5 V DC for as long as 20 minutes without fuel addition using two small (2.5 cm X 2.5 cm X 4 mm) ceramic wafer TEGs in series and a Kenyan charcoal Jiko. At 4 VDC you can charge three AAA NiMH batteries in series. Bright white LEDs can be operated at voltages as low as 3.2 volts, but as soon as you get below this they dim. Current should not be greater than 35 milliamps or damage to the LED occurs.

The trick is delta-T for the TEGs. Hot is easy- that's what our stoves do, but cool is difficult, especially when the TEG is only 4mm thick. Small inexpensive TEGs commonly found in computers etc. only generate sufficient power for LEDs when the temperature difference between hot & cold sides exceed 60 degrees C or so..... and damage can occur with some TEGs if the temperatures exceed 75 C. Heat tolerant TEGs cost more.

It's a work in progress, and I regret to say that the progress has been slow indeed.

rgds;
elk
--------------------------------
Elsen L. Karstad
elk@wananchi.com
www.chardust.com
Nairobi, Kenya

From adkarve at PN2.VSNL.NET.IN Tue Jun 1 00:42:23 2004
From: adkarve at PN2.VSNL.NET.IN (adkarve)
Date: Tue Aug 10 18:31:12 2004
Subject: Cracking oils
Message-ID: <TUE.1.JUN.2004.101223.0530.ADKARVE@PN2.VSNL.NET.IN>

Dear Crispin,
you have most probably rediscovered the Greek fire, which was used as a
weapon of war before the introduction of gunpowder into Europe by the
Mongols. Europe had pine resin and vegetable oil in plenty.
Yours A.D.Karve
----- Original Message -----
From: Crispin Pemberton-Pigott <crispin@newdawn.sz>
To: <STOVES@LISTSERV.REPP.ORG>
Sent: Sunday, May 30, 2004 5:08 AM
Subject: [STOVES] Cracking oils

> Dear Dr Tom
>
> I have been asking about cracking oils and resin. I tried heat alone:
>
> I put some sunflower cooking oil in a covered stainless steel pot on a
> hot stove until there emerged a significant amount of smoke (the
> temperature inside peaked).
>
> I then took it outside and opened the lid. After an initial burst of
> smoke from the contents, the liquid inside burst into flames and burned
> with a very clean pale blue flame until the liquid contents were gone.
> Sunflower oil does not burn like that
>
> That happened?
>
> Regards
> Crispin

From adkarve at PN2.VSNL.NET.IN Tue Jun 1 01:08:44 2004
From: adkarve at PN2.VSNL.NET.IN (adkarve)
Date: Tue Aug 10 18:31:12 2004
Subject: Conference in Pune in 2006
Message-ID: <TUE.1.JUN.2004.103844.0530.ADKARVE@PN2.VSNL.NET.IN>

Dear Stovers,
it is still early days. We may hold our conference in February or March
2006. For organising an international conference, we have to get the
permission from the Ministry of External Affairs. The complete programme of
the conference and the names of the potential participants have to be
supplied to the Ministry when we apply for their permission. That is why we
have started the process so early. Consent now does not make it compulsory
for anybody to attend, but if you gave the theme of your presentation, your
name and the country of which you are the citizen, it would be easier for us
to get the permission and for you to get a visa.
Yours
A.D.Karve

----- Original Message -----
From: Crispin Pemberton-Pigott <crispin@newdawn.sz>
To: <STOVES@LISTSERV.REPP.ORG>
Sent: Sunday, May 30, 2004 8:41 PM
Subject: Re: [STOVES] use of outside air with analysis KR

> Dear Kanchan
>
> >I got the point, its a cold air draught inside the room
> >that makes people to feel cold rather than the energy
> >absorbed by air to increase its temperature.
>
> Exactly.
>
> It would be interesting to put a hood over the fire to capture most of
> the smoke and feed it into the ceiling vent hole to see if you can get
> most of the smoke out of the room without losing a lot of heat. The
> heat lost could be quantified and a decision made about whether extra
> wood required (if any) was worth the improvement in air quality.
>
> Then a channel under the floor leading to the fire could provide about
> 1/2 the air required for the fire and you could quantify if there was a
> reduction in wood needed. In total there may be a saving + cleaner air
> + a higher degree of comfort without any stove at all - just a hood and
> changes to the air supply.
>
> The hood could in fact be in the form of a chimney made from local
> materials. If I lived there, that is what I would build for myself.
>
> Regards
> Crispin

From adkarve at PN2.VSNL.NET.IN Tue Jun 1 01:22:26 2004
From: adkarve at PN2.VSNL.NET.IN (adkarve)
Date: Tue Aug 10 18:31:12 2004
Subject: Energy and fertilizer from waste
Message-ID: <TUE.1.JUN.2004.105226.0530.ADKARVE@PN2.VSNL.NET.IN>

This refers to the discussion about winning energy as well as fertilizer
from soilid organic waste. Biogas is the solution to this problem. Because
this is a bacterial process, compounds containing N,P,K and micronutrients
are not destroyed. The slurry left behind can serve as manure.
A.D.Karve

From crispin at NEWDAWN.SZ Tue Jun 1 06:34:38 2004
From: crispin at NEWDAWN.SZ (Crispin Pemberton-Pigott)
Date: Tue Aug 10 18:31:12 2004
Subject: TEGs & LEDs
Message-ID: <TUE.1.JUN.2004.123438.0200.CRISPIN@NEWDAWN.SZ>

Dear Elsen

>Small inexpensive TEGs commonly found in computers
>etc. only generate sufficient power for LEDs when the
>temperature difference between hot & cold sides exceed
>60 degrees C or so..... and damage can occur with some
>TEGs if the temperatures exceed 75 C. Heat tolerant TEGs cost more.

I communicated with a Chinese producer last year and their reply to my
question about temperature was that I could exceed the hot side by quite a
bit without trouble because in reality the limit on their unit (about 300 C)
was that the hot plate against which I was pressing the TEG didn't actually
heat the TEG to the same temperature as it was being cooled all the time.
They felt a stove was a perfectly feasible application.

It seemed to me that one possibility was putting a TEG at the bottom of a
pot - but if the water runs out that is the end of the unit.

Putting it on the outside of a heat shield around the pot seems like it will
perform 'safest'. Cooling will require some non-liquid method.

My problem was that the Chinese units were quoted at $70 unless I bought
50,000 ($7.50 ea). The marketing aspect has not yet been cracked. They are
just too expensive in small quantities and will never get to large
quantities at the small quantity price.

Mention has been made of the White LED's but no one is comparing them with
HE-LED's which put out far more light. Are they also available in white? I
toured the website mentioned for LED's but they are way too expensive ($5 to
60 each).

Frankly, I don't care about the colour. You can locate a snake in the room
with a blue light if you have to!

No direct mention has been made about the current-device that LED's are so I
will just in case some people don't know and want to experiment a bit.

An LED is a current based (dependent) device, not a voltage based device.
Using one is a bit like hooking a plain diode across a battery. If you do
that it will burn out immediately. A light emitting diode has to have the
current flowing through it limited by a resistance of some kind - usually a
simple resistor. As there is a 'forward voltage drop' in the diode (usually
about 0.6 volts) the current is to a certain extent, or _may be_,
self-limiting at very low voltages.

If you want to mess around with little red LEDs taken from an old tape
player make sure you have a resistor in series so that the current flow does
not exceed the rated maximum.

The white LED's and 'lighting purpose' LED's can be complex inside with
multiple junctions and built-in resistors for which, of course, you pay.

If you hook ordinary blue, red and yellow diodes to a battery, you do not
need to put them in parallel. You can hook them in series. If they have a
forward voltage drop of 0.6 volts each, you will need to apply 1.8 volts or
no current flows. The resistor can then be recalculated to limit the
currrent flow to (say) 50 milliamps or whatever the rating of the units are.
My point is that the same 50 mA flowing through the blue LED can be used to
power the red and yellow ones. The voltage applied is irrelevant if the
resistor is limiting the flow of current. An LED does not need a 'certain
amount of voltage' nor does it require a stable voltage. It is all about
current. (I grant that some LED's have a high forward breakdown voltage.)

The highest overall efficiency is obtained when the applied voltage is as
close as possible to that needed to overcome the forward voltage drop (fvd)
of the combined units. A '3.5 volt LED' might be 5 units on series with 0.6
fvd each, plus a small amount more to accomodate the effect of the limiting
resistor.

The same three LED's described above can be connected in parallel and a weak
1 volt power supply hooked to it, but unfortunately one of them will hog the
power unless they each have a limiting resistor so be careful.

NOW: the TEG is a voltage rated but current _limited_ device which means not
only that the output voltage will swing wildly when you change the current
drawn from it, but that the current will not exceed a certain value. For
most purposes this is a disadvantage but for LED lighting it is a great
advantage. As the heat input (heat differential) rises the current will
only rise to a maximum based on (basically) the area of the unit. If the
LED's draw more current (as they are current hogging devices) it holds the
voltage from the TEG down. That doesn't matter. A rise in voltage from the
TEG won't bother the LED because the current from the TEG is automatically
limited by the nature of how it works, unlike a battery which can give huge
current even at low voltages (which is why your car starts). Batteries
_are_ limited by their internal chemistry, but for LED discussions, they a
too powerful for unregulated use.

Instead of paying for electronic parts to control voltages and current,
maintain constant levels of this and that, you could carefully select an LED
and TEG combination that match each other and given a stove application
where the heat differential between the hot and cold side never exceeds a
known Delta T. The TEG would drive the LED at full output power all the
time with no controls (or limiting resistor) on it whatsoever. Whatever the
voltage, the correct TEG can't supply more current than the unregulated LED
can deal with.

This layout is recommended for a single LED because as mentioned above: "The
same three LED's described above can be connected in parallel ...but
unfortunately one of them will hog the power unless they each have a
limiting resistor."

The simplest combination is what I am looking for in the rural areas.

Regards
Crispin

From hseaver at CYBERSHAMANIX.COM Tue Jun 1 04:46:48 2004
From: hseaver at CYBERSHAMANIX.COM (Harmon Seaver)
Date: Tue Aug 10 18:31:12 2004
Subject: Energy and fertilizer from waste
In-Reply-To: <000501c447bb$8dfc5fc0$345341db@adkarve>
Message-ID: <TUE.1.JUN.2004.034648.0500.HSEAVER@CYBERSHAMANIX.COM>

On Tue, Jun 01, 2004 at 10:52:26AM +0530, adkarve wrote:
> This refers to the discussion about winning energy as well as fertilizer
> from soilid organic waste. Biogas is the solution to this problem. Because
> this is a bacterial process, compounds containing N,P,K and micronutrients
> are not destroyed. The slurry left behind can serve as manure.
> A.D.Karve

I think the biosolids he is wanting to gasify have already been through a
"methane digester" of sorts, in the sewage treatment plant, and this is just the
dried sludge. That's how it's done here locally at any rate, and the sad thing
is they just flare off the gas, burning it for nothing. I even wrote a letter to
the newspaper about it, but the sewage treatment people claimed it was too
"dirty" to use for anything. 8-(
Perhaps if oil prices continue to climb they might see the error of their
ways, but I doubt it.

--
Harmon Seaver
CyberShamanix
http://www.cybershamanix.com
Hoka hey!

From kenboak at STIRLINGSERVICE.FREESERVE.CO.UK Tue Jun 1 09:56:46 2004
From: kenboak at STIRLINGSERVICE.FREESERVE.CO.UK (Ken Boak)
Date: Tue Aug 10 18:31:12 2004
Subject: TEGs & LEDs
Message-ID: <TUE.1.JUN.2004.145646.0100.KENBOAK@STIRLINGSERVICE.FREESERVE.CO.UK>

Crispin & Stovers

Your mention of white LEDs reminded me of a product called a shake-light -
which consistes of a tiny rare earth magnet costing 10 cents suspended
inside a coil of wire and connected to a white LED.

You can see it here

http://shakelight.notanumberinc.com/revamp/ and other sites too!

I am sure a linear reciprocating steam engine with a neodymium magnet and a
tin can boiler could be made for a couple of bucks with the magnet directly
on the piston. Rotary motion would not even be necessary for this idea.

Something on the lines of this:

As steam pressure builds up in the tin can it forces the magnet piston up a
cylinder tube against a spring.
As the piston rises it uncovers a port which lets the steam out and reduces
the pressure. The spring pushes the magnet back down and waits until
pressure is up again. With the right spring and magnet this could be made
to oscillate at a reasonable rate - 10 or 20 Hz.

The piston and spring act as an automatic safety valve for the device.

A 1cm diameter piston would be more than ample

regards,

Ken

> Crispin

From psanders at ILSTU.EDU Tue Jun 1 10:05:51 2004
From: psanders at ILSTU.EDU (Paul S. Anderson)
Date: Tue Aug 10 18:31:12 2004
Subject: Conference in Pune in 2006
In-Reply-To: <000301c447bb$7f1733e0$345341db@adkarve>
Message-ID: <TUE.1.JUN.2004.090551.0500.PSANDERS@ILSTU.EDU>

AD,

I like the Feb or March dates better. No conflict with ETHOS in late
January (usually) where there MIGHT be additional meetings attached such as
the EPA meeting this past early February. Best to avoid such possible
conflicts.

I would certainly want to attend your 2006 meeting. My topic would be
"Update on the 2005 Advances of the TLUD/IDD Small Gasifiers for Domestic
Energy." I think we could consider Tom Reed to be a co-author unless he
wants to also have a separate topic such as "Progress Toward the Billion
Stoves Goal." (I have not spoken with Tom about this, but I expect that
he will be interested.)

Sounds like "Pune 2006" could be a major stoves event. It is already on my
calendar so that I can plan for additional India-area activities in that
time period.

Paul

At 10:38 AM 6/1/04 +0530, adkarve wrote:
>Dear Stovers,
>it is still early days. We may hold our conference in February or March
>2006. For organising an international conference, we have to get the
>permission from the Ministry of External Affairs. The complete programme of
>the conference and the names of the potential participants have to be
>supplied to the Ministry when we apply for their permission. That is why we
>have started the process so early. Consent now does not make it compulsory
>for anybody to attend, but if you gave the theme of your presentation, your
>name and the country of which you are the citizen, it would be easier for us
>to get the permission and for you to get a visa.
>Yours
>A.D.Karve
>
>----- Original Message -----
>From: Crispin Pemberton-Pigott <crispin@newdawn.sz>
>To: <STOVES@LISTSERV.REPP.ORG>
>Sent: Sunday, May 30, 2004 8:41 PM
>Subject: Re: [STOVES] use of outside air with analysis KR
>
>
> > Dear Kanchan
> >
> > >I got the point, its a cold air draught inside the room
> > >that makes people to feel cold rather than the energy
> > >absorbed by air to increase its temperature.
> >
> > Exactly.
> >
> > It would be interesting to put a hood over the fire to capture most of
> > the smoke and feed it into the ceiling vent hole to see if you can get
> > most of the smoke out of the room without losing a lot of heat. The
> > heat lost could be quantified and a decision made about whether extra
> > wood required (if any) was worth the improvement in air quality.
> >
> > Then a channel under the floor leading to the fire could provide about
> > 1/2 the air required for the fire and you could quantify if there was a
> > reduction in wood needed. In total there may be a saving + cleaner air
> > + a higher degree of comfort without any stove at all - just a hood and
> > changes to the air supply.
> >
> > The hood could in fact be in the form of a chimney made from local
> > materials. If I lived there, that is what I would build for myself.
> >
> > Regards
> > Crispin

Paul S. Anderson, Ph.D.
Dept of Geography - Geology (Box 4400), Illinois State University
Normal, IL 61790-4400 Voice: 309-438-7360; FAX: 309-438-5310
E-mail: psanders@ilstu.edu - Internet items: www.ilstu.edu/~psanders
NOTE: Retired from teaching. Active in Stoves development.
For fastest contact, please call home phone: 309-452-7072

From snkm at BTL.NET Tue Jun 1 10:24:14 2004
From: snkm at BTL.NET (Peter Singfield)
Date: Tue Aug 10 18:31:12 2004
Subject: TEGs & LEDs
Message-ID: <TUE.1.JUN.2004.082414.0600.SNKM@BTL.NET>

Ken;

Probably better to go with a tiny impulse turbine -- a small "fan" in front
of a steam jet.

Use any suitable tiny DC motor for the generator. Mount fan direct to
shaft. Blow steam on fan -- etc.

Think of a small pressure cooker device -- fill with water -- insert into
heat flow -- gives light until water is exhausted. You then take out --
cool off -- replace water -- etc.

Or just use a standard pressure cooker on the stove -- the genset mounted
directly on the cover.

Lot's of simple/easy ways to skin this cat!!

Peter / Belize

At 02:56 PM 6/1/2004 +0100, Ken Boak wrote:
>Crispin & Stovers
>
>Your mention of white LEDs reminded me of a product called a shake-light -
>which consistes of a tiny rare earth magnet costing 10 cents suspended
>inside a coil of wire and connected to a white LED.
>
>
>You can see it here
>
>http://shakelight.notanumberinc.com/revamp/ and other sites too!
>
>
>I am sure a linear reciprocating steam engine with a neodymium magnet and a
>tin can boiler could be made for a couple of bucks with the magnet directly
>on the piston. Rotary motion would not even be necessary for this idea.
>
>Something on the lines of this:
>
>As steam pressure builds up in the tin can it forces the magnet piston up a
>cylinder tube against a spring.
>As the piston rises it uncovers a port which lets the steam out and reduces
>the pressure. The spring pushes the magnet back down and waits until
>pressure is up again. With the right spring and magnet this could be made
>to oscillate at a reasonable rate - 10 or 20 Hz.
>
>The piston and spring act as an automatic safety valve for the device.
>
>A 1cm diameter piston would be more than ample
>
>
>
>regards,
>
>
>
>Ken
>
>> Crispin
>

From w.burroughs at VERIZON.NET Tue Jun 1 12:05:36 2004
From: w.burroughs at VERIZON.NET (Hank)
Date: Tue Aug 10 18:31:12 2004
Subject: Jmla Stove
Message-ID: <TUE.1.JUN.2004.090536.0700.W.BURROUGHS@VERIZON.NET>

If there are regular winds blowing in the mountains, why could we not design
a small wind machine system to make electricity for the lights? Such a
system could power flourescent as well as LED lights. Maybe base it on
used hard drive motors and cell phone batteries to keep the costs low. If
this is not something for the "stovers" to do, could we coordinate with
other researchers interested in helping mountain people? Seems like several
on this list are members of University reseach centers.

BTW this might also provide power for fans to make a forced draft for the
stoves and some type of ventilation system.

Hank in gthe high desert

From tmiles at TRMILES.COM Tue Jun 1 12:51:35 2004
From: tmiles at TRMILES.COM (Tom Miles)
Date: Tue Aug 10 18:31:12 2004
Subject: White LED Lamp
Message-ID: <TUE.1.JUN.2004.125135.0400.TMILES@TRMILES.COM>

This weekend we posted Ken Goyer's pictures of his LED lamps in Mexico.

See "Stove Powered Lighting" May 2004 on the Stoves web page at:
http://www.repp.org/discussiongroups/resources/stoves/

Tom Miles

From crispin at NEWDAWN.SZ Tue Jun 1 14:19:53 2004
From: crispin at NEWDAWN.SZ (Crispin Pemberton-Pigott)
Date: Tue Aug 10 18:31:12 2004
Subject: NO to NO2
Message-ID: <TUE.1.JUN.2004.201953.0200.>

Dear Chemists

In the following reaction:

Formed NO is converted in the catalyst to N2 according to the basic
reaction: NO + CO to N2 + CO2

How much heat is released?

Thanks to Lurker Vern for the site
http://www.industrialheating.com/CDA/ArticleInformation/features/BNP__Fe
atures__Item/0,2832,61232,00.html

Regards
Crispin

From crispin at NEWDAWN.SZ Tue Jun 1 14:40:46 2004
From: crispin at NEWDAWN.SZ (Crispin Pemberton-Pigott)
Date: Tue Aug 10 18:31:12 2004
Subject: White LED Lamp
Message-ID: <TUE.1.JUN.2004.204046.0200.>

Dear Stovers

>This weekend we posted Ken Goyer's pictures of his LED lamps in Mexico.

I had a look - very impressive.

How much did the LED's cost?

Exactly what is the power source?

Thanks
Crispin

From dbneeley at YAHOO.COM Tue Jun 1 18:15:36 2004
From: dbneeley at YAHOO.COM (David Neeley)
Date: Tue Aug 10 18:31:12 2004
Subject: Lights--especially CFL
In-Reply-To: <200406010402.i5142T729764@ns1.repp.org>
Message-ID: <TUE.1.JUN.2004.151536.0700.>

I use compact fluorescent bulbs nearly everywhere in my
home, and I have learned a few details some of you may not
know.

First, the type of ballast is important. The older style,
mechanical ballast creates a flicker (in AC current types)
that is at the frequency of the current. This is a flicker
which, if it's 60 cycles, is not visible to everyone
consciously but is very bad for the eyesight. (Most people
could see it at 50 cycles).

When mechanical ballasts were all that was available,
people needed to use pairs of tubes to "even out" the
flicker and be better for the eyes.

More advanced ballasts are all electronic, and use a much
higher frequency oscillation for the tubes. The most modern
CFL bulbs are usually electronically ballasted--which is
why the costs have come down so much recently.

The color temperature of the tubes depends upon the
phosphor material in the tubes. Generally, I use at least
5,000 degree Kelvin tubes that are easier on the eyes and
produce less glare than the lower-temperature tubes. IIRC,
sunlight is around 6,500 degrees Kelvin--and there are
various companies that make a close analog to sunlight in
their products--but they are generally very expensive and
often have a secondary tube with rare earth phosphors to
supply some of the spectrum.

It is some of these "rare earth" phosphors which
deteriorate fairly rapidly. Thus, if you buy an "Ott Lite"
or a Verilux daylight balance lamp, to keep the same
quality light as they give when new you would need to
change the elements fairly regularly, as some of the
phosphors are relatively unstable.

All of which said, if you can produce sufficient
electricity from the stoves, I would completely agree that
a CFL that runs on the current produced would be the most
cost-efficient light source available today.

In my opinion, LED lights are best where portability or
very long life are more important than individual cost.
Thus, traffic signals, automotive brake lights,
flashlights, and similar applications are becoming very
popular. Because of the lower lumens-per-watt in the
current technology, though, I believe household
illumination is presently somewhat impractical if a decent
CFL setup is a viable option.

The mention of the Stirling Engine as a possible home power
source is an intriguing one--but, I believe, somewhat
impractical due to the present cost of manufacture of such
an engine. However, I believe that in a village situation
there might be an application for a stove with an
associated Stirling engine that could drive much more than
one or two CFL lamps--but, in fact, be a resource for a
small community that could promote literacy and community.
An interesting Website regarding the design parameters of
the Stirling engine is from Ohio University and is
published on the Stirling Engine Society of the U.S. at
http://www.sesusa.org/SEDAF.htm.

Some of the commercial Stirling generator sets are
presently able to operate for more than 50,000 hours in
remote locations with little or no maintenance. This would
seem to be an ideal application for this technology if it
could be manufactured inexpensively enough.

In addition to Nepal, perhaps our friends in India might
find this a worthwhile avenue of exploration? With the
manufacturing ability present there, I would imagine this
could be a very worthwhile product that would use heat that
otherwise may be wasted to power electrical devices not
only including light but also radio and perhaps
high-efficiency freezers or refrigerators.

David

__________________________________
Do you Yahoo!?
Friends. Fun. Try the all-new Yahoo! Messenger.
http://messenger.yahoo.com/

From pverhaart at IPRIMUS.COM.AU Tue Jun 1 18:54:19 2004
From: pverhaart at IPRIMUS.COM.AU (Peter Verhaart)
Date: Tue Aug 10 18:31:12 2004
Subject: NO to NO2
In-Reply-To: <000601c44805$0d4182d0$e49dfea9@home>
Message-ID: <WED.2.JUN.2004.085419.1000.PVERHAART@IPRIMUS.COM.AU>

Not 2 NO + 2 CO --> N2 + 2 CO2?

Peter (molecule miser) Verhaart

At 20:19 01/06/2004 +0200, you wrote:
>Dear Chemists
>
>In the following reaction:
>
>Formed NO is converted in the catalyst to N2 according to the basic
>reaction: NO + CO to N2 + CO2
>
>How much heat is released?
>
>Thanks to Lurker Vern for the site
>http://www.industrialheating.com/CDA/ArticleInformation/features/BNP__Fe
>atures__Item/0,2832,61232,00.html
>
>Regards
>Crispin

From dstill at EPUD.NET Wed Jun 2 00:03:35 2004
From: dstill at EPUD.NET (Dean Still)
Date: Tue Aug 10 18:31:12 2004
Subject: Winiarski and Baldwin
Message-ID: <TUE.1.JUN.2004.210335.0700.DSTILL@EPUD.NET>

Dear Friends,

We had a beautiful confab here the last couple days and spent a while
comparing and contrasting two methods for increasing heat transfer by
Winiarski and Baldwin. Larry Winiarski maintains the same cross sectional
area throughout the stove. Meaning that the fuel magazine, combustion
chamber, vertical internal chimney above the fire, area under the pot and up
the side of the pot has the same CSA. Powerful simple method.

Sam Baldwin figures that firepower and size of channel between pot and skirt
are related. You can't narrow the gap too much if you want enough air to
enter the combustion chamber for good combustion. Another easy to use
method. Page 48 Biomass Cookstoves, available from VITA.

It turns out that although the two designers came at the problem from
different ends, that their gaps tend to be very similar. In fact many of the
problems came out with the same solution using the two methods!

I was reminded during this study that frequently the pot is more important
than the stove in determining wood use when cooking. A large diameter pot
with a little water in the bottom makes a great heat exchanger. Optimizing
the pot is so powerful that it can negate stove differences since combustion
efficiency doesn't vary much and is over 90% anyway. Improving the pot's
ability as a heat exchanger, pretty poor, results in a dramatic rise in
efficiency.

I was also reminded that stoves that burn more than 1 kilo per hour need to
have pretty big gaps which limit efficiency. A small hot fire under a big
shallow pot with a little water in it that is placed in a sealed close
celled insulated box to complete simmering after boiling uses remarkably
little wood.

System efficiency brings us to better pots, pot skirts and hayboxes. Stoves
are improvements over the open fire mainly to make cooking easier and
reduce, remove emissions. Both are important.

Best,

Dean

From snienhuys at SNV.ORG.NP Wed Jun 2 00:47:47 2004
From: snienhuys at SNV.ORG.NP (Sjoerd Nienhuys)
Date: Tue Aug 10 18:31:12 2004
Subject: Jmla Stove
Message-ID: <WED.2.JUN.2004.103247.0545.SNIENHUYS@SNV.ORG.NP>

Mountain Stovers,

Wind power is very well possible in upper Mustang areas as well as other
mountain areas where afternoon thermals develop into forceful steady winds.
See my mission report on Jomsom on www.icimod.org/snv for details what went
wrong in Jomsom and why wind is commercially hardly useful in those areas.
Currently some explorations are underway by Winrock Int. to use the
afternoon wind for water lifting, providing also for irrigation in the
desert like area, while surplus water can be run from the high storage
through a Peltric for night illumination (or small battery charging); this
has more economic potential than feeding electricity into large batteries or
the grid.

Above-ground wiring is as expensive as small PV panels, but subject to
frequent repair. Under-ground wiring in HDPE pipe is done in Jumla, Ilam
and other areas, but keeping small windmills operating in very harsh areas
for low-income individuals is economically out of the question, especially
if there are no maintenance facilities.

For people who have difficulty raising one Euro in a week or a month, an
investment of a few hundred Euros or more for a group-based small electric
windmill is only a dream. The equipment and the technology exist, that is
not the problem. Batteries have to be brought overland during a two to four
weeks trek and are used in solar PV panels that are now common in the area.
Car batteries last only a few years. Appropriate deep-cycle or
maintenance-free batteries are often considered too expensive because people
tend to look most at the investment money, not at the durability or economic
lifetime. Solar PV is primarily used/wanted for illumination and TV, not at
all for stove fans. There is a cheap hand-operated fan available from
China, used by almost every household. If they are very poor, they blow in
a pipe.
With the wind picking up every afternoon, controllable chimneys can be
installed, costing no electricity (see former message).

Unless entrepreneurs are strongly subsidised in demonstration projects as
well for delivering and installing goods with vast consumer and continuous
maintenance subsidies, technologies will only be developed/used by some very
rich inhabitants who want the comfort. With a lack of local government
structure and finance systems, lack of local knowledge about the various
options, advantages and disadvantages or cost information, little progress
is possible. One of the first steps is to work on the information supply;
explaining people what exists, how it works and what it costs. After some
of the richer inhabitants apply and understand the system, the others will
gradually follow.

As indicated in the former message, developing better stoves or other
renewable energy for low-income people in remote areas is often a complex
social and financial issue. For the stoves discussion list entering in
WLED, wind power, passive solar energy. etc. may be too much of a
diversification.

Regards,

Sjoerd Nienhuys
Senior Renewable Energy Advisor SNV-Nepal
Tel: +977-1-5523444, extension 112
snienhuys@snv.org.np
----------------------------------------------------------------------------
------------

Behalf Of Hank
Sent: Tuesday, June 01, 2004 9:51 PM

BTW this might also provide power for fans to make a forced draft for the
stoves and some type of ventilation system.

Hank in gthe high desert

From psanders at ILSTU.EDU Wed Jun 2 01:17:46 2004
From: psanders at ILSTU.EDU (Paul S. Anderson)
Date: Tue Aug 10 18:31:12 2004
Subject: Absortion chillers using our heat
In-Reply-To: <opr8xhv3fs6c175d@localhost>
Message-ID: <WED.2.JUN.2004.001746.0500.PSANDERS@ILSTU.EDU>

Matt brought up another interesting question. I am not sure what he means
by an "Absortion chillers" (except when I think of propane
refrigerators). But he said "cheaply" and that caught my attention. Matt
and others, can you provide info, please?

Perhaps this topic is not for the "Gasifier people" as much as it is for
the "Stoves List Serve people", so I am posting this message there
also. (if you are on both list, like I am, you get to see it twice, and
decide where to send your reply.)

Paul

At 02:34 PM 6/1/04 -0400, Matthew Pottinger wrote:
>I also think a lot about the wasted heat problem. I had the same idea of
>simply heating water for co-generation, or, you could use that heat to
>drive an absortion chiller, and cool the gases even more! I am sure pretty
>cold temperatures could be reached that way, which would reduce the tar
>problem even further, and increase power output. The gas would be much
>denser at say 0 deg. C than 70-100.
>
>Absortion chillers can be made cheaply can they not? I have seen home made
>ones used as ice makers. Energy can also be stored in the ice for long
>periods of time.
>
>
>
>On Tue, 1 Jun 2004 19:20:18 +0200, Krzysztof Lis <santo@poczta.fm> wrote:
>
>>P> 4. First New Question: If the hot gases (clean or otherwise) must
>>P> be cooled first before becoming of good use, we are probably
>>P> "wasting" the heat in those gases. Therefore, IF that is a lot of
>>P> energy lost, and IF that heat could have been put into a steam
>>P> boiler, and IF the "still-hot" gases were simply combusted for heat
>>P> (not for mechanical power in an IC engine), WOULD that make a
>>P> meaningful difference to improve the otherwise poor image of steam
>>P> generation as an inefficient way to use the gases? [NOTE the
>>P> number of "IFs" in this question.]
>>
>>A book "Generatorbetrieb" by St.v.Szenasy shows an example of using
>>this heat -- you cool those gasses by heating water in some tank, and
>>then add this water to the generator -- this way of saving energy was
>>used in "Wisco" generator, which runs on anthracit (coal), very dry
>>fuel, which doesn't produce much hydrogen. Even better idea would be
>>to use (if it's possible) produced gas to evaporate this water and
>>then (at best) overheat this steam, and then send it to the gas gene-
>>rator.
>>
>>As for burning hot gas inside boiler or stove or any other burner,
>>there might be (I think) three difficulties:
>>- hot gas means large specific volume and large volumetric flows, so
>>larger (more energy consuming) fan / blower to pump this gas to the
>>place in which it'll be used (if you use any in your case)
>>- hot gas = fan with metal blades
>>- burner might not be suitable for the gas of large specific volume (I
>>think there might be problem with mixing proper amounts of producer
>>gas with oxidizer, but burner's aren't my interest).
>>
>>--
>>Best regards,
>> Krzysztof Lis / Poland
>
>
>
>--
>
>Matthew Pottinger
>
>Student
>Environmental Technology Program
>Durham College
>Ontario, Canada
>
>"Never underestimate people's
>ability to suppress inconvenient realities."
>
>"We could avoid the extinction of the human race, but it just wouldn't be
>economically feasible."

From pverhaart at IPRIMUS.COM.AU Wed Jun 2 03:01:21 2004
From: pverhaart at IPRIMUS.COM.AU (Peter Verhaart)
Date: Tue Aug 10 18:31:12 2004
Subject: Absortion chillers using our heat
In-Reply-To: <4.3.1.2.20040602001120.0252b330@mail.ilstu.edu>
Message-ID: <WED.2.JUN.2004.170121.1000.PVERHAART@IPRIMUS.COM.AU>

Absorption refrigerators work by virtue of the absorption (solubility) of
ammonia NH3, in water. If a strong ammonia solution is heated; the vapour
driven off is rich in ammonia, which can be condensed at ambient
temperature under the pressure generated by the boiler. The liquid ammonia
is admitted to a space with a lower pressure where it evaporated, absorbing
heat eg cooling the space. The low pressure ammonia is absorbed in cool
water (degassed water from the boiler); this is an exothermic process. The
strong ammonia solution is then returned by a pump to the boiler.
A very ingenious process makes use of the partial pressure of ammonia in a
hydrogen atmosphere so the total pressure in the circuit remains almost
constant. The transport of liquid is taken care of by a gas lift pump.

Peter Verhaart

At 00:17 02/06/2004 -0500, you wrote:
>Matt brought up another interesting question. I am not sure what he means
>by an "Absortion chillers" (except when I think of propane
>refrigerators). But he said "cheaply" and that caught my attention. Matt
>and others, can you provide info, please?

From adkarve at PN2.VSNL.NET.IN Tue Jun 1 21:48:41 2004
From: adkarve at PN2.VSNL.NET.IN (adkarve)
Date: Tue Aug 10 18:31:12 2004
Subject: Electricity from wind
Message-ID: <WED.2.JUN.2004.071841.0530.ADKARVE@PN2.VSNL.NET.IN>

Dear Hank,
this is a very good idea indeed. The individual householders may find it
technically and financially difficult to do, but a NGO can help them. In the
Indian part of the Himalaya, flour grinding mills are run water wheels.
HESCO, a NGO, has a programme of fitting traditional waterwheels with ball
bearings so that their efficiency is increased. They then attach an
electricity generator to the waterwheel, producing electricity for that
village.
Yours A.D.Karve
----- Original Message -----
From: Hank <w.burroughs@VERIZON.NET>
To: <STOVES@LISTSERV.REPP.ORG>
Sent: Tuesday, June 01, 2004 9:35 PM
Subject: Re: [STOVES] Jmla Stove

> If there are regular winds blowing in the mountains, why could we not
design
> a small wind machine system to make electricity for the lights? Such a
> system could power flourescent as well as LED lights. Maybe base it on
> used hard drive motors and cell phone batteries to keep the costs low. If
> this is not something for the "stovers" to do, could we coordinate with
> other researchers interested in helping mountain people? Seems like
several
> on this list are members of University reseach centers.
>
> BTW this might also provide power for fans to make a forced draft for the
> stoves and some type of ventilation system.
>
> Hank in gthe high desert

From jeff.forssell at CFL.SE Wed Jun 2 04:20:24 2004
From: jeff.forssell at CFL.SE (Jeff Forssell)
Date: Tue Aug 10 18:31:12 2004
Subject: Absortion chillers using our heat
Message-ID: <WED.2.JUN.2004.102024.0200.JEFF.FORSSELL@CFL.SE>

I have written a little about my experience w?th kerosene/el driven absoption refrigerators (4 yr in Tanzania).

http://biphome.spray.se/jeff.forssell/KeroFrig.htm

Electrolux used to have a good animation about abs. refrigerators which I had a link to. But it's no longer there.

I tried Googling and found some other interesting stuff (though no animations)
http://www.nh3tech.org/absorption.html (the 3rd type is the kind i had)
http://energi.fysikk.uio.no/rebus/phd_2003/SOA-solar_cooling.doc covers various types of cooling arrangements that could be solar driven

> Absorption refrigerators work by virtue of the absorption
> (solubility) of ammonia NH3, in water.

From hseaver at CYBERSHAMANIX.COM Wed Jun 2 07:02:59 2004
From: hseaver at CYBERSHAMANIX.COM (Harmon Seaver)
Date: Tue Aug 10 18:31:12 2004
Subject: Absortion chillers using our heat
In-Reply-To: <5.2.0.9.2.20040602165259.021ea7c8@pop.iprimus.com.au>
Message-ID: <WED.2.JUN.2004.060259.0500.HSEAVER@CYBERSHAMANIX.COM>

On Wed, Jun 02, 2004 at 05:01:21PM +1000, Peter Verhaart wrote:
> Absorption refrigerators work by virtue of the absorption (solubility) of
> ammonia NH3, in water. If a strong ammonia solution is heated; the vapour
> driven off is rich in ammonia, which can be condensed at ambient
> temperature under the pressure generated by the boiler. The liquid ammonia
> is admitted to a space with a lower pressure where it evaporated, absorbing
> heat eg cooling the space. The low pressure ammonia is absorbed in cool
> water (degassed water from the boiler); this is an exothermic process. The
> strong ammonia solution is then returned by a pump to the boiler.

Pump? There's no pump on any of the propane or kerosene refrigerators I've
owned. They don't use any electricity whatsoever. Nor is there on the icy-ball
design I posted previously.

> A very ingenious process makes use of the partial pressure of ammonia in a
> hydrogen atmosphere so the total pressure in the circuit remains almost
> constant. The transport of liquid is taken care of by a gas lift pump.
>
> Peter Verhaart
>
>
>
> At 00:17 02/06/2004 -0500, you wrote:
> >Matt brought up another interesting question. I am not sure what he means
> >by an "Absortion chillers" (except when I think of propane
> >refrigerators). But he said "cheaply" and that caught my attention. Matt
> >and others, can you provide info, please?

--
Harmon Seaver
CyberShamanix
http://www.cybershamanix.com
Hoka hey!

From crispin at NEWDAWN.SZ Wed Jun 2 07:08:10 2004
From: crispin at NEWDAWN.SZ (Crispin Pemberton-Pigott)
Date: Tue Aug 10 18:31:12 2004
Subject: TEGs & LEDs
Message-ID: <WED.2.JUN.2004.130810.0200.CRISPIN@NEWDAWN.SZ>

Dear Elsen

Although the question was sent on the side, it is a relevant to my briefer explanation.

>One question- why do the 12VDC automotive LED
>lights- whether single or clusters have a small blocking
>diode on one leg, in addition to the requisite resistor
>on the other?

Diodes have a rated peak inverse voltage (an ability _not_ to conduct backwards) which why we like them so much. This is the PIV rating written 600V PIV which will rectify, or block in reverse, 425 volts AC (RMS) (600/1.41=425v). A light emitting diode may have a low PIV as it is built to optimize light, not for its ability to rectify AC.

The extra diode you find is probably there to increase the PIV rating of the LED in case you accidentally hook it up backwards to a higher or similar voltage. It can also be that the LED is 'leaky' in reverse or is instantly damaged when connected backwards, or that the LED puts out a small amount of light when hooked up backwards and in order to prevent mechanics thinking it is properly connected (a dull leaky glow?) the extra diode is there to make sure it is obviously wrong so it gets corrected. The PIV rating is the most likely reason.

I have also used diodes in a way that makes sure that if something fails (like when an SCR melts and conducts in both directions) the supply fuse blows preventing equipment damage.

Regards
Crispin
3DA0BI

From tmiles at TRMILES.COM Wed Jun 2 10:50:27 2004
From: tmiles at TRMILES.COM (Tom Miles)
Date: Tue Aug 10 18:31:12 2004
Subject: [ethos] Winiarski and Baldwin
Message-ID: <WED.2.JUN.2004.075027.0700.TMILES@TRMILES.COM>

Dean,

We should be able to get the system effiiciency - pots, skirts and
hayboxes - messages across in graphics and photos. I'll put up any
contributions on the web. :-)

Regards

Tom Miles

----- Original Message -----
From: "Dean Still" <dstill@epud.net>
To: <STOVES@LISTSERV.REPP.ORG>; <ethos@vrac.iastate.edu>
Sent: Tuesday, June 01, 2004 9:03 PM
Subject: [ethos] Winiarski and Baldwin

> Dear Friends,

[snip]

> System efficiency brings us to better pots, pot skirts and hayboxes.
Stoves
> are improvements over the open fire mainly to make cooking easier and
> reduce, remove emissions. Both are important.
>
> Best,
>
> Dean
>
>
> ---
> To unsubscribe, send email to majormail@vrac.iastate.edu with
> this as the first line in the BODY of the message: unsubscribe ethos
> ---
>

From crispin at NEWDAWN.SZ Wed Jun 2 18:23:43 2004
From: crispin at NEWDAWN.SZ (Crispin Pemberton-Pigott)
Date: Tue Aug 10 18:31:12 2004
Subject: How to use the LED's for stove or battery lighting
Message-ID: <THU.3.JUN.2004.002343.0200.>

Dear Electronic Stovers

http://www.allelectronics.com/spec/LED-75.pdf is an example of the way
LED's are rated.

Looking at another site I found that the blue LED's are weak in
illuminating power and less efficient. White LED's are downright
inefficient and are probable three well chosen colours mounted on a
single chip. To give you an idea of what is available:

Ratings: appear to be in Lumens per watt Lw and given at a 'current
forward' If (capital i+f).

Notation: Lw@If = nnnn

Example
TLCW5100 [part name]
White (5500 K) [equivalent temperature of a black body]
3.9 (< 4.5 v) [applied volts, must be kept under 4.5 in this
case]
Lw@If >1000 at 30ma [over 1000 lumens per watt, when 30 milliamps is
passing through it. At 3.9 volts DC and 30 ma this is 0.117 watts so it
is probably 117 lumens] (is this possible?) Some are rated at 135
milliwatts.

If someone knows that this rating is not being interpreted correctly
please send in a message. Lw is not defined anywhere I looked.
Luminous intensity is given in 'mcd'.

For stovers it is the comparison between colours that is interesting.

Lumens per watt for different colours (these are high efficiency LED's)
White = 1000
Red = 20,000
Yellow = 14,000
Green = 7000
Blue = 2500

All the units are 30ma and approximately the same voltage (2.7 - 4)

Results of survey:
The PIV rating is very low - some are only rated at 5 volts reverse
(under 50 microamps reverse flow). Some are 15 volts, but that is still
low. This explains why the vehicle lights have an extra diode -
protection from being hooked up backwards.

The brightness can be increased greatly if the unit it pulsed, for
example on for 10 milliseconds and off for 90ms. (10% duty cycle).
Obviously this involves many extra parts.

It appears that for a rural very low cost lighting system, rather than
getting white LED's it would be better to get 1 x Red and 1 x Yellow and
1 x green to produce a significantly red-orange light that is very
bright. This is the most light per $. Red (625 nm wavelength) is the
most robust (1 amp shocks for 10 micro.s.) and brightest.

If you can get enough voltage (the three in series would require about
5.4 volts minimum and 13.5 maximum) they could be hooked to a TEG that
gives out only 50 ma. The forward voltage required to get 30ma through
the 3 units in series is about 4 volts each (different colours are
different voltages!) 11 volts for the three in series is about right:
2.7 + 4 + 3.9.

Failing to get a TEG or generator that gives 11 volts and automatically
chokes when 50ma is reached, you will have to put limiting resistors in
series with the set, or individually. You could use a single zener
diode to limit the voltage to 12 (now up to 4 parts total plus the TEG).

The reverse voltage (PIV limit) is very low, often only slight higher
than the forward voltage, i.e. 5vDC PIV agains 4.5 vDC forward. If you
think there is a chance it will be hooked up backwards, you had better
put in a tiny diode to prevent reverse flow. It will only cost a few
cents, but it will add 0.3 to 0.6 forward voltage drop (i.e. 11 + 0.6 =
11.6 now required).

I suspect that the easist way to get 12 volts DC with a naturally
limited 50 millamp capacity is to use a very small chemical battery
based on something like metals+urine or vitamin C or the acidic juice of
a local fruit. A rack of simple wires made of dissimilar metals could
do that easily. Lemon juice, iron wire and galvanized wire will
generate that amount of power. I think stove builders will not have
trouble getting that sort of power from just about anything connected to
the stove. The problem is the high voltage. In gavl+iron+lemon juice
it = about 10 cells.

What about piezo-electric power - higher voltage and low currents
available there! Perhaps one red 4 volt LED would be bright enough to
use as an emergency light, or yellow. Burning pine sap is yellow....

So the trick will be to find the correct combination of parts that work
without regulation, controls and power draining bypass circuits.

Regards
Crispin

From lanny at ROMAN.NET Wed Jun 2 19:12:13 2004
From: lanny at ROMAN.NET (Lanny Henson)
Date: Tue Aug 10 18:31:12 2004
Subject: Haybox cap and draft booster
Message-ID: <WED.2.JUN.2004.191213.0400.LANNY@ROMAN.NET>

For the Charcoal Slow Cooker I used an insulated cover to cap the top of
the pot, sort of a haybox topper. This cover has an exhaust outlet and adds
to the total draft height. To trap the retained heat I just cap the exhaust
outlet with a can. It will hold 7 liters of water hot four several hours.
I have made my insulated draft cover deep enough to hold a second stacked
pot for this stove.
It is simple and works great. I will put together some how to instructions.
How about an insulated cover from a bucket with no exhaust outlet to just
sit it over a hot pot.
And I was thinking, how about an insulated cover or covers on a griddle.
http://www.lanny.us/cover1.jpg
http://www.lanny.us/cover2.jpg
Lanny Henson

>Dean,
>We should be able to get the system effiiciency - pots, skirts and
>hayboxes - messages across in graphics and photos. I'll put up any
>contributions on the web. :-)
>Regards
>Tom Miles

>----- Original Message -----
From: "Dean Still" <dstill@epud.net>
To: <STOVES@LISTSERV.REPP.ORG>; <ethos@vrac.iastate.edu>
Sent: Tuesday, June 01, 2004 9:03 PM
Subject: [ethos] Winiarski and Baldwin
> Dear Friends,
[snip
> System efficiency brings us to better pots, pot skirts and hayboxes.
Stoves
> are improvements over the open fire mainly to make cooking easier and
> reduce, remove emissions. Both are important.
> Best,
> Dean

From larencorie at AXILAR.NET Wed Jun 2 22:57:37 2004
From: larencorie at AXILAR.NET (LarenCorie)
Date: Tue Aug 10 18:31:13 2004
Subject: How to use the LED's for stove or battery lighting
Message-ID: <WED.2.JUN.2004.225737.0400.LARENCORIE@AXILAR.NET>

Crispin Pemberton-Pigott <crispin@NEWDAWN.SZ> wrote

> Ratings: appear to be in Lumens per watt Lw and given at a 'current
> forward' If (capital i+f).
>
> Notation: Lw@If = nnnn
>
> Example
> TLCW5100 [part name]
> White (5500 K) [equivalent temperature of a black body]
> 3.9 (< 4.5 v) [applied volts, must be kept under 4.5 in this
> case]
> Lw@If >1000 at 30ma [over 1000 lumens per watt, when 30 milliamps is
> passing through it. At 3.9 volts DC and 30 ma this is 0.117 watts so it
> is probably 117 lumens] (is this possible?) Some are rated at 135
> milliwatts.
>
> If someone knows that this rating is not being interpreted correctly
> please send in a message. Lw is not defined anywhere I looked.
> Luminous intensity is given in 'mcd'.
>
> For stovers it is the comparison between colours that is interesting.
>
> Lumens per watt for different colours (these are high efficiency LED's)
> White = 1000
> Red = 20,000
> Yellow = 14,000
> Green = 7000
> Blue = 2500

Hello Crispin;

Something is very wrong with your lumen numbers.
Somehow, some are off, by a factor of over 400.
Those lights put out much less lumens/watt, than
the 50 cent (US) white fluorescents, I mentioned.
Many are less efficient than incandescent bulbs.
________________

(quote)

"The most efficient colored LEDs have overall luminous
efficiency of approx. 53 lumens/watt and others may soon
hit 60. The most efficient white LEDs get around 25
lumens/watt and may soon get 30 lumens/watt, with ones
that achieve 60 lumens/watt expected to be in production
in 2005.

For comparison:

USA usual 100W "A19" incandescent - 17.1 lumens/watt.
Compact fluorescents - mostly 45-60 lumens/watt including
ballast losses. 32 watt T8 fluorescent in "average condition"
- typically around 80 lumens/watt including ballast losses. "
http://members.misty.com/don/light.html

"The Brightest and Most Efficient LEDs and where to get them!"
http://members.misty.com/don/led.html

This explains some of the false claims that you may read
about the output of LEDs. This is an honest site, which
had published some wild claims, but has learned better.
http://www.otherpower.com/otherpower_lighting.html

http://www.luxeonstar.com/

-Laren Corie-
Passive Solar Building Design Since 1975

From larencorie at AXILAR.NET Wed Jun 2 23:27:36 2004
From: larencorie at AXILAR.NET (LarenCorie)
Date: Tue Aug 10 18:31:13 2004
Subject: Absortion chillers using our heat
Message-ID: <WED.2.JUN.2004.232736.0400.LARENCORIE@AXILAR.NET>

For any climate, which has frequent below-freezing temperatures
in the winter, it is very practical to store winter "coolth" for summer
refrigeration. By using a brine solution, it is even possible to maintain
temperatures below freezing. In most parts of the world there are
PET plastic bottles, which need to be used or disposed. Filled with
water, they make excellent heat and/or coolth storage containers, as
they can handle as much as 200PSI (pound/sq inch), and have a very
substantial surface area for quick heat exchange. They can also be
used with other PCMs (phase change materials), for instance paraffin,
as a very effective bed warm (aprox 400 BTU/ 2liter bottle) In a
7000-9000 degree-day F? (3900-5000 C?) climate, an insulated ice
cellar of about 2m? will store enough containers to keep a refrigerator
cold all year. There are ways to increase that efficiency, further.
Insulation can be from a variety of recycled sources, like more of the
same PET bottles. This system has no moving parts, and freezes the
water or brine, via passive thermosyphoning.

-Laren Corie-
Passive Solar Building Design Since 1975

From larencorie at AXILAR.NET Thu Jun 3 00:00:50 2004
From: larencorie at AXILAR.NET (LarenCorie)
Date: Tue Aug 10 18:31:13 2004
Subject: TEGs & LEDs.......Shake Lights
Message-ID: <THU.3.JUN.2004.000050.0400.LARENCORIE@AXILAR.NET>

Ken Boak <kenboak@STIRLINGSERVICE.FREESERVE.CO.UK> wrote

> Your mention of white LEDs reminded me of a product called a
> shake-light - which consistes of a tiny rare earth magnet costing 10
> cents suspended inside a coil of wire and connected to a white LED.

> You can see it here
>
> http://shakelight.notanumberinc.com/revamp/ and other sites too!

Isn't that what they were putting in the soles of sneakers
a few years ago, to produce the flashing LEDs.

http://www.creative-science.org.uk/gensimple1.html
http://www.amasci.com/amateur/coilgen.html

-Laren Corie-

From crispin at NEWDAWN.SZ Thu Jun 3 07:09:20 2004
From: crispin at NEWDAWN.SZ (Crispin)
Date: Tue Aug 10 18:31:13 2004
Subject: Paraffin Safety Association of South Africa www.pasasa.org.za
Message-ID: <THU.3.JUN.2004.130920.0200.CRISPIN@NEWDAWN.SZ>

Dear Aspirant Paraffin Stove Makers

The Paraffin Safety Association of South Africa is holding a paraffin stove
designing competition.

See their website for reports and performance tests, safety standards and
much more.

I received a call from Nazeema Ahmad last week saying they are having a
conference on the subject and they are full into the media with ads on
paraffin safety this week. Big money behind this initiative.

See http://www.pasasa.org/new/safeStove.html

Testing is according to the South African Bureau of Standards test:

"All nine stoves tested failed the current SABS standards;
All the stoves failed an average of six or more of the SABS codes; " etc

Comprehensive tests are given for all the popular pressure and wick stoves
from the links on this page.

"Paraffin Safety Association added an additional test to the SABS standards
"After operating the stove for 1 hour, knock it over, while it is in
operation and note the consequences". Again, the most commonly used paraffin
stoves, non-pressure or wick stoves, all immediately erupted in flames when
knocked over."

The Panda stove explodes in a huge ball of fire when subjected to this last
test as the fuel is about 20 degrees above the flash point. I say 'last
test' because the stove is unusable after it has been knocked over once.
Frequently hundreds of homes are burned down because they are so close
together.

From crispin at NEWDAWN.SZ Thu Jun 3 07:37:54 2004
From: crispin at NEWDAWN.SZ (Crispin)
Date: Tue Aug 10 18:31:13 2004
Subject: How to use the LED's for stove or battery lighting
Message-ID: <THU.3.JUN.2004.133754.0200.CRISPIN@NEWDAWN.SZ>

Dear Laren

Thanksf or that. I thogh it was unbelievable too. No idea what the figures
are, but it is still useful for comparison. The white LED's are not very
good performers, even if there are bright ones around.

>Something is very wrong with your lumen numbers.

>USA usual 100W "A19" incandescent - 17.1 lumens/watt.
>Compact fluorescents - mostly 45-60 lumens/watt including
>ballast losses. 32 watt T8 fluorescent in "average condition"
> - typically around 80 lumens/watt including ballast losses. "

I wanted to know if you meant (earlier) that the ballast was built inside
the bulb or the 'device'. Can I hook 12 VDC to a bulb and get it to light
up?

>http://www.otherpower.com/otherpower_lighting.html

Thanks for that one!

Crispin

From a31ford at INETLINK.CA Thu Jun 3 07:45:26 2004
From: a31ford at INETLINK.CA (a31ford)
Date: Tue Aug 10 18:31:13 2004
Subject: TEGs & LEDs
In-Reply-To: <00ba01c44891$ed620ba0$cb83fea9@md>
Message-ID: <THU.3.JUN.2004.064526.0500.A31FORD@INETLINK.CA>

Dear Crispin & All,

FYI
One your point about the extra Diode in an automotive light, gone LED, you
are correct about the "In case one hooks it up backward", however, the other
side of the coin is also for "inter-mixing". The diode also allows these
types of lights to be used in a "grounded when off, V+ when on" (not the
normal "Open when off, V+ when on") style circuit. With the manufactures
doing more than one signal on the same wire, this is becoming a very
important issue.

Greg

-----Original Message-----
From: The Stoves Discussion List [mailto:STOVES@LISTSERV.REPP.ORG]On
Behalf Of Crispin Pemberton-Pigott
Sent: Wednesday, June 02, 2004 6:08 AM
To: STOVES@LISTSERV.REPP.ORG
Subject: Re: [STOVES] TEGs & LEDs

Dear Elsen

Although the question was sent on the side, it is a relevant to my briefer
explanation.

>One question- why do the 12VDC automotive LED
>lights- whether single or clusters have a small blocking
>diode on one leg, in addition to the requisite resistor
>on the other?

Diodes have a rated peak inverse voltage (an ability _not_ to conduct
backwards) which why we like them so much. This is the PIV rating written
600V PIV which will rectify, or block in reverse, 425 volts AC (RMS)
(600/1.41=425v). A light emitting diode may have a low PIV as it is built
to optimize light, not for its ability to rectify AC.

The extra diode you find is probably there to increase the PIV rating of the
LED in case you accidentally hook it up backwards to a higher or similar
voltage. It can also be that the LED is 'leaky' in reverse or is instantly
damaged when connected backwards, or that the LED puts out a small amount of
light when hooked up backwards and in order to prevent mechanics thinking it
is properly connected (a dull leaky glow?) the extra diode is there to make
sure it is obviously wrong so it gets corrected. The PIV rating is the most
likely reason.

I have also used diodes in a way that makes sure that if something fails
(like when an SCR melts and conducts in both directions) the supply fuse
blows preventing equipment damage.

Regards
Crispin
3DA0BI

From crispin at NEWDAWN.SZ Thu Jun 3 12:23:14 2004
From: crispin at NEWDAWN.SZ (Crispin Pemberton-Pigott)
Date: Tue Aug 10 18:31:13 2004
Subject: TEGs & LEDs
Message-ID: <THU.3.JUN.2004.182314.0200.>

Dear Greg

You're a genius!

So you can run left signal and right signal on one wire. Interesting.

Regards
Crispin

From crispin at NEWDAWN.SZ Thu Jun 3 12:26:44 2004
From: crispin at NEWDAWN.SZ (Crispin Pemberton-Pigott)
Date: Tue Aug 10 18:31:13 2004
Subject: Strange things in Nepal
Message-ID: <THU.3.JUN.2004.182644.0200.>

Dear Stovers

There is an innovative, cheap water filter that takes arsenic out of the
water being made in rural Nepali communities.

http://web.mit.edu/civenv/html/people/alumni_newsletters/winter_03/art3.
htm

It would be wonderful if we can come up with a stove as innovative as
this example of water engineering.

Regards
Crispin

From crispin at NEWDAWN.SZ Thu Jun 3 17:32:40 2004
From: crispin at NEWDAWN.SZ (Crispin Pemberton-Pigott)
Date: Tue Aug 10 18:31:13 2004
Subject: Working out combustion efficiency
Message-ID: <THU.3.JUN.2004.233240.0200.>

Dear Stovers

On November 27, 2001 Alex English wrote:

Subject: Re: CO detection

> Hello Das,
>
> Good ideas!
> However I think we need to take it a little farther. Your method will
> sample gases in a chimney, just under a pot or in a vent hood exhaust,

> but it does not account for excess air dilution through the stove.
> Without measuring O2 , CO2 or total mass flow we can't fairly compare
> combustion quality.

If you want to get the answer in a single portable instrument that can
record sets of data, the TSI CA-6203 or CA-6205 can give a correct
answer to the combustion quality question. It reads out directly on the
LCD display.

Regards
Crispin

From steve at SUSTAINABLEVILLAGE.COM Thu Jun 3 20:15:15 2004
From: steve at SUSTAINABLEVILLAGE.COM (Steve Troy)
Date: Tue Aug 10 18:31:13 2004
Subject: Venting smoke from 3rd World 'kitchens' / dwellings
In-Reply-To: <174B12AFEA57714CB88A8259F20DB771368335@server.nimbusprojects.com>
Message-ID: <THU.3.JUN.2004.181515.0600.STEVE@SUSTAINABLEVILLAGE.COM>

Does anyone have a good suggestion for Peter's request below for a
cheap smoke hood design?
Steve Troy

>Dear S.V.:
>
>I couldn't believe the unbelievably bad indoor air quality in the so
>called kitchens of northern Nicaragua ........... I visited last
>November.
>
>It clearly has to be a major health problem for Nica women and their
>small children.
>
>Has S.V. ever run across any simple ... CHEAP ... smoke hood designs
>that could be used to vent the greater %age of this vile smoke out
>of the houses?
>
>Many thanks for any help!
>
>Peter Ojamaa,
>Calgary, Alberta.
"Peter Ojamaa" <Petero@nimbusprojects.com>

===============================================================
The Sustainable Village, LLC 717 Poplar Ave.
Boulder, CO 80304
email: steve@sustainablevillage.com web site:
http://www.sustainablevillage.com
voice 303-998-1323 ext. 100, 888-317-1600 fax 303-449-1348
Sustainable Resources 2004
http://www.sustainableresources.org
"Resources for the Developing World"

From psanders at ILSTU.EDU Thu Jun 3 22:30:45 2004
From: psanders at ILSTU.EDU (Paul S. Anderson)
Date: Tue Aug 10 18:31:13 2004
Subject: Manually powered forced air Was Re: [STOVES] Jmla Stove
In-Reply-To: <KGEALNHAOCPCAHEOEGHHGEIECGAA.snienhuys@snv.org.np>
Message-ID: <THU.3.JUN.2004.213045.0500.PSANDERS@ILSTU.EDU>

At 10:32 AM 6/2/04 +0545, Sjoerd Nienhuys wrote:
>Mountain Stovers,
snip
> Solar PV is primarily used/wanted for illumination and TV, not at
>all for stove fans. There is a cheap hand-operated fan available from
>China, used by almost every household. If they are very poor, they blow in
>a pipe.
>With the wind picking up every afternoon, controllable chimneys can be
>installed, costing no electricity (see former message).

Sjoerd and Stovers,

Please give us more information about the hand-operated fan from China, and
how they are used (important because the TYPE of stove influences the
usefulness of the forced air).

And when blowing on a pipe, I assume you mean that is a more comfortable
and directed way to blow on a fire instead of bending down and blowing into
the tinder when lighting. Typically, how long would they be blowing?

And how long would they typically be using the fan to assist the stove?

There are many interesting issues concerning use of the relatively
predictable and consistent wind to enhance the draft in a chimney. From
your experience, what can you tell us about successes (and failures) with
trying to get appropriate draft via the wind?

Anyone else had these experiences? Maybe David Whitfield in the highlands
of Bolivia? (David, that was a request for a comment from you.)

Paul
Paul S. Anderson, Ph.D.
Dept of Geography - Geology (Box 4400), Illinois State University
Normal, IL 61790-4400 Voice: 309-438-7360; FAX: 309-438-5310
E-mail: psanders@ilstu.edu - Internet items: www.ilstu.edu/~psanders
NOTE: Retired from teaching. Active in Stoves development.
For fastest contact, please call home phone: 309-452-7072

From psanders at ILSTU.EDU Thu Jun 3 23:29:24 2004
From: psanders at ILSTU.EDU (Paul S. Anderson)
Date: Tue Aug 10 18:31:13 2004
Subject: Absortion chillers using our heat
In-Reply-To: <BA468CE631F86A4D831FCBD4EB1C692C4D7B0A@floyd.cfl.local>
Message-ID: <THU.3.JUN.2004.222924.0500.PSANDERS@ILSTU.EDU>

Stovers,

Thanks for the responses. From the GASification list serve, I received
only one main reply, and it sent me to
http://www.ggw.org/~cac/IcyBall/crosley_icyball.html and at
http://www.ggw.org/~cac/IcyBall/HomeBuilt/HomeBuilt.html and at
http://www.fridge.lionheart.net (site of Rich Carey)

From the Stovers, Jeff (message below) had some great info.

NOW my question is, what can be made at LOW cost for developing
countries? I am thinking of cool, not cold, (to freeze water would be
nice, but that is not as important as cool so that milk, etc does not spoil.)

Anyone with experience or with desire to get into this would be most
welcome. I have already send a message to Rich Carey tonight, and I hope
he expresses interest.

Paul

At 10:20 AM 6/2/04 +0200, Jeff Forssell wrote:
>I have written a little about my experience w?th kerosene/el driven
>absoption refrigerators (4 yr in Tanzania).
>
>http://biphome.spray.se/jeff.forssell/KeroFrig.htm
>
>Electrolux used to have a good animation about abs. refrigerators which I
>had a link to. But it's no longer there.
>
>I tried Googling and found some other interesting stuff (though no animations)
>http://www.nh3tech.org/absorption.html (the 3rd type is the kind i had)
>http://energi.fysikk.uio.no/rebus/phd_2003/SOA-solar_cooling.doc covers
>various types of cooling arrangements that could be solar driven
>
> > Absorption refrigerators work by virtue of the absorption
> > (solubility) of ammonia NH3, in water.

From psanders at ILSTU.EDU Fri Jun 4 00:10:26 2004
From: psanders at ILSTU.EDU (Paul S. Anderson)
Date: Tue Aug 10 18:31:13 2004
Subject: "lemon juice" battery
In-Reply-To: <000001c448f0$541ceff0$e49dfea9@home>
Message-ID: <THU.3.JUN.2004.231026.0500.PSANDERS@ILSTU.EDU>

Stovers,

I never cease to be amazed at Crispin's knowledge!!! Now I want to pick
his brain about ONE of the things in his previous message, which said:

At 12:23 AM 6/3/04 +0200, Crispin Pemberton-Pigott wrote:
>Dear Electronic Stovers
>snip
>I suspect that the easist way to get 12 volts DC with a naturally
>limited 50 millamp capacity is to use a very small chemical battery
>based on something like metals+urine or vitamin C or the acidic juice of
>a local fruit. A rack of simple wires made of dissimilar metals could
>do that easily. Lemon juice, iron wire and galvanized wire will
>generate that amount of power. I think stove builders will not have
>trouble getting that sort of power from just about anything connected to
>the stove. The problem is the high voltage. In gavl+iron+lemon juice
>it = about 10 cells.

I am after enough power to drive a small fan or blower. The ways to obtain
the power are numerous, and ALL should be made known so the target
societies can choose what is best for their circumstances.

Well, some galv+iron+lemon juice (or urine?) might be as "high tech" as
some places can handle. So, just how "sustainable" and "appropriate" would
this be?

Tom Reed's campstove uses 1.5 volt motor ( I do not know the amps or watts).

Information please. Perhaps we do need the instructions to a "high school
science class" experiment. But we already know that it "works". The
issue is, can it "sustainably" and "appropriately" work?

In anticipation of some comments:

Yes, forced air even with a VERY small motor is important. and

Yes, SOME people are so poor that wire and lemon juice (and some old glass
jars?) are about all that they can "afford" (scrounge) in the near or mid
future.

This is not limited to only "lemons". What other acidic liquids could we
use? But I like the subject name of this message because we should all
take the "lemons" in our lives and turn them into "lemonade."

Or should that be called "lemon-aid" ?

From snienhuys at SNV.ORG.NP Fri Jun 4 00:30:43 2004
From: snienhuys at SNV.ORG.NP (Sjoerd Nienhuys)
Date: Tue Aug 10 18:31:13 2004
Subject: Manually powered forced air Was Re: [STOVES] Jmla Stove
In-Reply-To: <4.3.1.2.20040603211809.0203ef00@mail.ilstu.edu>
Message-ID: <FRI.4.JUN.2004.101543.0545.SNIENHUYS@SNV.ORG.NP>

Mountain stovers,

Picture of fan is to be seen on www.icimod.org/snv the document: Mission
report High Altitude Biogas Reactor, photo page 9.
It is an aluminium or sheet steel hair blower type fan with a small gear to
enhance the speed of the centrifuge.
The picture demonstrates the use, often only a minute or so, to get the fire
going again. Mainly when new wood is added to the fire. At the high
altitudes the wood usually goes into a simmer when not regularly fanned.

The wind fan on the chimney is depicted in the background report of Pakistan
stoves (same website and on stove website). It costs less than one USD,
locally made and VERY effective.

Regards,

Sjoerd Nienhuys
Senior Renewable Energy Advisor SNV-Nepal
Tel: 5523444, extension 112.
snienhuys@snv.org.np

Sjoerd and Stovers,

Please give us more information about the hand-operated fan from China, and
how they are used (important because the TYPE of stove influences the
usefulness of the forced air).

And how long would they typically be using the fan to assist the stove?

Anyone else had these experiences? Maybe David Whitfield in the highlands
of Bolivia? (David, that was a request for a comment from you.)

From crispin at NEWDAWN.SZ Fri Jun 4 03:52:31 2004
From: crispin at NEWDAWN.SZ (Crispin Pemberton-Pigott)
Date: Tue Aug 10 18:31:13 2004
Subject: Manually powered forced air
Message-ID: <FRI.4.JUN.2004.095231.0200.CRISPIN@NEWDAWN.SZ>

Dear Paul

In the Sahel they make cast aluminum hand powered fans which are not even
bought from China. In Maradi, Niger, for example, they are made by melting
down smashed Nigerian car parts smuggled by camel over the border from
Kaduna. Such raw material sells for about $0.35 per kilo.

The fans are small hand powered motorcycle front wheels running a rubber
band (innertube strip) connected to a bicycle hub to which the cast aluminum
centrifugal fan is connected. The driven "pulley" is a 20mm diameter tube
so the fan can run upwards of 3000 RPM.

The fan itself consists of two sand-cast housings and the impeller. All the
parts are made or cast on site, the bicycle or motorcycle parts being
scrounged around.

This fan is used to melt aluminum in an enamelled steel bowl. The moulds
are as usual made from termite mound sand. Any impeller and housing can be
used as a pattern to make another one.

Regards
Crispin

From crispin at NEWDAWN.SZ Fri Jun 4 05:11:35 2004
From: crispin at NEWDAWN.SZ (Crispin Pemberton-Pigott)
Date: Tue Aug 10 18:31:13 2004
Subject: "lemon juice" battery
Message-ID: <FRI.4.JUN.2004.111135.0200.CRISPIN@NEWDAWN.SZ>

Dear Paul

I must say that (nearly) all this knowledge is useless (as they use to say
in the show "Beyond the Fringe")!

>The problem is the high voltage. In galv+iron+lemon juice
>it = about 10 cells.

>I am after enough power to drive a small fan or blower.

All things considered, it is probably best to hand crank something while the
fire is starting and then switch to thermo-electric. I have been thinking
about the thermocouple again. One poster mentioned only getting a low
voltage from the one he tried in multiple units. I think that may now be
the available result if it is done correctly. It is not something I have
looked at much but apparently one can get 50-75 mV from one junction so
shouldn't we be looking at that? That is only 20 junctions at zero amps.

>Well, some galv+iron+lemon juice (or urine?) might be as "high tech" as
>some places can handle. So, just how "sustainable" and "appropriate"
>would this be?

I think it is very sustainable if people can get used to the idea of making
their own power. The juice from the crushing of sisal is very corrosive and
might be (when concentrated) highly suitable for power generation. It is a
problem to dispose of for that reason. Rural handicrafts based on sisal
could supply the liquid for lighting or small fans.

>Or should that be called "lemon-aid" ?

There is a book on making something called 'urine water' or 'dung water'
that was put out by the Peace Corps in Uganda. It explains how to make two
pits and put dung in one and slowly make a concentrated acidic solution.
This was used to mix with clay and when the type of clay was right, it 'set'
like cement. It is probably possible to use this method to make stove parts
before firing them - in other words make thin sections that 'set' and which
are fired later.

Clay pot batteries (concentric tubular cells) have been around since
Egyptian times - certainly 3500 years, though it is anyone's guess what they
did with the power. Some claim they had electric lights.

We are just reinventing the (electric) wheel!

Regards
Crispin

From rmiranda at INET.COM.BR Fri Jun 4 07:35:18 2004
From: rmiranda at INET.COM.BR (Rogerio Carneiro de Miranda)
Date: Tue Aug 10 18:31:13 2004
Subject: Venting smoke from 3rd World 'kitchens' / dwellings
In-Reply-To: <p06100571bce56c7dabcf@[192.168.181.10]>
Message-ID: <FRI.4.JUN.2004.083518.0300.RMIRANDA@INET.COM.BR>

Steve and Peter: As far as I am aware, www.ITDG.org has done some good
work regarding instalings hood and other ventilation improvements in Kenia
and elsewhere in Africa.

In Nicaragua we have the Ecostove factory, which could be an option to
improve household air quality. Peter where in Nicaragua did you
go..... In Managua PROLE?A has an office and Ecostove factory.

regards

rogerio miranda

At 21:15 3/6/2004, Steve Troy wrote:
>Does anyone have a good suggestion for Peter's request below for a
>cheap smoke hood design?
>Steve Troy
>
>>Dear S.V.:
>>
>>I couldn't believe the unbelievably bad indoor air quality in the so
>>called kitchens of northern Nicaragua ........... I visited last
>>November.
>>
>>It clearly has to be a major health problem for Nica women and their
>>small children.
>>
>>Has S.V. ever run across any simple ... CHEAP ... smoke hood designs
>>that could be used to vent the greater %age of this vile smoke out
>>of the houses?
>>
>>Many thanks for any help!
>>
>>Peter Ojamaa,
>>Calgary, Alberta.
>"Peter Ojamaa" <Petero@nimbusprojects.com>
>
>--
>
>===============================================================
> The Sustainable Village, LLC 717 Poplar Ave.
>Boulder, CO 80304
> email: steve@sustainablevillage.com web site:
>http://www.sustainablevillage.com
> voice 303-998-1323 ext. 100, 888-317-1600 fax
> 303-449-1348
> Sustainable Resources 2004
>http://www.sustainableresources.org
> "Resources for the Developing World"

From kenboak at STIRLINGSERVICE.FREESERVE.CO.UK Fri Jun 4 07:46:46 2004
From: kenboak at STIRLINGSERVICE.FREESERVE.CO.UK (Ken Boak)
Date: Tue Aug 10 18:31:13 2004
Subject: Manually powered forced air
Message-ID: <FRI.4.JUN.2004.124646.0100.KENBOAK@STIRLINGSERVICE.FREESERVE.CO.UK>

Crispin,

Thank you for your description of the aluminium sand casting process you
have observed in Maradi.

Once you have made one fan, you can force draft a furnace and make more
(teach a man to fish etc .....)

I have seen a pedal powered forge in Prague, used by a street blacksmith.

I would be interested to know what other rural metal working skills are in
evidence.

Which of the following would a typical metal worker have access to:

Welding equipment

Drilling machine, lathe and mill

Sheet metal working equipment - bending and folding bars etc

Basic blacksmithing equiptment - forge, anvil, hammers, tongs

Non ferrous casting - is this restricted to aluminium because of its low
melting point or are brass, bronze, zinc worked as well?

regards,

Ken Boak

London

From pverhaart at IPRIMUS.COM.AU Fri Jun 4 07:55:19 2004
From: pverhaart at IPRIMUS.COM.AU (Peter Verhaart)
Date: Tue Aug 10 18:31:13 2004
Subject: Manually powered forced air Was Re: [STOVES] Jmla Stove
In-Reply-To: <4.3.1.2.20040603211809.0203ef00@mail.ilstu.edu>
Message-ID: <FRI.4.JUN.2004.215519.1000.PVERHAART@IPRIMUS.COM.AU>

At 21:30 03/06/2004 -0500, you wrote:
>At 10:32 AM 6/2/04 +0545, Sjoerd Nienhuys wrote:
>>Mountain Stovers,
>snip
>> Solar PV is primarily used/wanted for illumination and TV, not at
>>all for stove fans. There is a cheap hand-operated fan available from
>>China, used by almost every household. If they are very poor, they blow in
>>a pipe.

>>And when blowing on a pipe, I assume you mean that is a more comfortable
>and directed way to blow on a fire instead of bending down and blowing into
>the tinder when lighting. Typically, how long would they be blowing?

Blowing IN a pipe. You leave some distance between your mouth and the pipe
so that the relatively high velocity jet from your mouth entrains more air
into the pipe, resulting in less expenditure of breath and more wind into
the fire. This can be kept up for much longer than straight blowing.

Peter Verhaart

From reecon at MITSUMINET.COM Fri Jun 4 09:48:38 2004
From: reecon at MITSUMINET.COM (reecon)
Date: Tue Aug 10 18:31:13 2004
Subject: Tracking unit for parabolic cooker
Message-ID: <FRI.4.JUN.2004.164838.0300.REECON@MITSUMINET.COM>

Hallo stovers,
I noticed a poster that said someone had developed a simple tracking device for parabolic solar cookers, i seem to have deleted it. Could i have that information please. (Dr. Karve?).
Regards,
Musungu.

From dstill at EPUD.NET Fri Jun 4 10:19:11 2004
From: dstill at EPUD.NET (Dean Still)
Date: Tue Aug 10 18:31:13 2004
Subject: Absortion chillers using our heat
In-Reply-To: <4.3.1.2.20040603215204.02510cd0@mail.ilstu.edu>
Message-ID: <FRI.4.JUN.2004.071911.0700.DSTILL@EPUD.NET>

Dear Paul,

The next time you are at Aprovecho we can fire up the Icy- Ball that Larry
and I made. Makes 18 pounds of ice from a 45 minute firing. The Servel
system is safer however.

Best,

Dean

From crispin at NEWDAWN.SZ Fri Jun 4 08:19:32 2004
From: crispin at NEWDAWN.SZ (Crispin Pemberton-Pigott)
Date: Tue Aug 10 18:31:13 2004
Subject: Manually powered forced air
Message-ID: <FRI.4.JUN.2004.141932.0200.CRISPIN@NEWDAWN.SZ>

Dear Ken

>I would be interested to know what other rural metal working
>skills are in evidence.

>Which of the following would a typical metal worker have access to:

Typical means something small and in the informal sector. Except for one
shop I saw in Addis Ababa which was an informal sector machine shop with
little machines for everything, they are monotonously ill-equipped in
Africa, on average.

>Welding equipment
140 to 200 amp welder, usually air cooled.
Some have an angle grinder, a highly prized pssession, frequently purloined
and sold on the black market. Hanging onto grinders is difficult for us
formal sector people.

>Drilling machine, lathe and mill
At the most, a hand drill.

>Sheet metal working equipment - bending and folding bars etc
Pliers. Tin snips. Tinkers' hammers. Cold chisels. Many countries cut
sheets thicker than 'tin' with a cold chisel. In Ethiopia a guy cut me a
piece of 3mm with a cold chisel. I was appalled. Rare are 'matel working
machines' which means a guillotine with plates for shearing hot rolled steel
angles, round bar etc. People live and die with a welder, a very small
guillotine (to 13mm round bar) an angle grinder (used for cutting all stell
sections) and a few hand tools. Some have a generator for welding as Shops
in rural areas need bars on them. Some have brazing equipment to repair
cars. With this set of tools you can make a living making burglar bars
only.

>Basic blacksmithing equipment - forge, anvil, hammers, tongs
The Foundry guys (unexpectedly) frequently have some forging tools. This is
because some things like large ladles are actually hot-hammered aluminum
ingots.

>Non ferrous casting - is this restricted to aluminium because of its low
melting point or are brass, bronze, zinc worked as well?
No that I have seen, but in southern West Africa there are people casting
bronze/brass for tourist things.

It might interest you all to know that welding rods can be made in the
village if you have access to plain wire and suger. An Iranian who worked
all his life in Bahrain as a welder and retired to Nakuru in Kenya taught me
how to do it. No electricity required. In some places like rural Nepal it
might be useful if rods are expensive.

Regards
Crispin

From phoenix98604 at EARTHLINK.NET Fri Jun 4 13:45:43 2004
From: phoenix98604 at EARTHLINK.NET (Art Krenzel)
Date: Tue Aug 10 18:31:13 2004
Subject: Manually powered forced air
Message-ID: <FRI.4.JUN.2004.104543.0700.PHOENIX98604@EARTHLINK.NET>

Crispin,

You said:
> It might interest you all to know that welding rods can be made in the
> village if you have access to plain wire and suger. An Iranian who worked
> all his life in Bahrain as a welder and retired to Nakuru in Kenya taught
me
> how to do it. No electricity required. In some places like rural Nepal
it
> might be useful if rods are expensive.

Having done Code Welding for a time, I am interested in your welding rod
manufacturing technology. I wonder what the presence of carbon and water
vapor in the weld area does to the weld integrity? I would like to learn
more about this since it obviously works.

They might use the technique that MIG welders use - if a little welding sort
of works, then just use more.

Art Krenzel, P.E.
PHOENIX TECHNOLOGIES
10505 NE 285TH Street
Battle Ground, WA 98604
360-666-1883 voice
phoenix98604@earthlink.net

From crispin at NEWDAWN.SZ Fri Jun 4 14:40:42 2004
From: crispin at NEWDAWN.SZ (Crispin Pemberton-Pigott)
Date: Tue Aug 10 18:31:13 2004
Subject: Heat from radiation v.s. conduction using shiny (real) pots
Message-ID: <FRI.4.JUN.2004.204042.0200.CRISPIN@NEWDAWN.SZ>

Dear Stovers

I have been checking out the difference in heat received from radiation and
conduction when cooking with ordinary shiny aluminum pots, seeing as that is
what people use.

I have hear various figures bandied about with regard to how many times more
heat is yielded to the pot when it is radiated instead of conducted either
from touching a metal surface or from touching hot gases. My thumb-suck
experiments were somewhat surprising.

First, I went to a pot spinning shop and had them make me a lipped
handle-less pot 152 deep and 220 in diameter. This I sunk into a small
downdraft coal stove so that the whole area of the pot was exposed to hot
gases with passage gaps of about 10mm.

In a regular stove like a Rocket 2-pot with a fire under the first pot (Pot
1) the gases then pass around Pot 2 to pick up heat otherwise wasted. There
was a good picture posted some time ago of a stainless steel 2-pot Rocket
stove with integrated oven. It was at the ETHOS meeting. I have used that
particular unit so I had some idea of what it was like and what my stoves
are like with a similar heat-collection pot.

My plan was to see what happens if the pot is highly polished. It will tend
not to pick up radiated heat and then it will tend to keep heat in once it
gets hold of it because its radiation coefficient is so poor.

Second, I put 5 litres of water into the pot in position 2 (collecting waste
heat). This took 33 minutes to come to a vigorous boil. By the time it did
the mirror finish was covered with a light dusting of white ash which wasn't
all that surprising. I suppose it insulated it a tiny bit. The part of the
pot which was not exposed to the front or side of the gas stream remained
clean and shiny. I suspect that nearly none of the heat that was in the pot
radiated away towards the chimney from that 'back' surface. In other words,
it was partially self-insulating by being reflective.

Third, I balanced a large (240mm) diameter pot over the fire so that the
bottom was about 50mm away from the red coals. This was a sanded aluminum
finish on the bottom with highly polished sides. The idea was to pick up
heat and boil a small amount of water. It was about 2 litres and boiled in
about 11 minutes.

Fourth, I got tired of holding the pot and rested it on two 12mm steel bars
spanning the fire. This resulted in a higher boiling rate which interested
me as the huge amount of radiated heat was, according what I have heard
about the effectiveness of radiation, supposed to *way* outweigh the effect
of conducted heat from sitting on the thin bar contact area.

Looking in I could see that the boiling was coming not from the bottom where
all the radiation hit the pot but from 2 clearly defined lines of bubbles
corresponding to where it sat on the rods. The water bubbled like crazy
along those two lines and hardly at all from the rest of the bottom, even
though it was 50mm from at least 4 to 5 KW of radiant heat. The silvery
bottom is an effective reflector.

Fifth, I placed over the coals an old battered aluminum pot with a burned
black bottom (230 mm diameter, 4 litre). It heated far faster than the new
pot did, but it still liked the contact with the rods.

Sixth, I placed a black 3mm thick mild steel plate over the fire (completely
removing radiation) and put the large pot on top of it. Surprisingly, in
spite of the shrinking fire it brought 6+ litres of water to a low boil. I
expected that would not be possible because of the low power input through
the plate, however the ability of the pot to retain heat insides its
polished walls was amazing.

Conclusion: I think this radiated heat business needs a good looking into.
On the face of it, conduction was a far stronger deliverer of heat to a
clean aluminum pot than radiation was. If I had used polished stainless
steel the effect would have been even more pronounced. It is possible that
conduction of heat to shiny pots is much more important, perhaps by an order
of magnitude, than it has been given credit for. As distance from the fire
to the pot is often a 'defining criterion' of stove manuals, it is likely
that significant changes are needed in the approach to heat transfer theory
given in DIY manuals.

This has a lot of interesting implications for people cooking with paraffin
(clean burning ones) and charcoal. People like charcoal because it doesn't
dirty the pots, but I'll bet they don't know that they should use a black
plate in between a shiny pot and the fire to save fuel. Perhaps it should
be perforated. Who knows? Has anyone been looking?

I think this is something everyone should try at home to see what they find.
Use a shiny stainless steel pot and put it on a flat black plate over a gas
fire, charcoal fire, wood fire and an electric hot plate. I will bet that
the heat transfer and heat retention when using an electric stove without a
plate in between is excellent, and that when using a charcoal fire it
improves with some form of a plate.

I wouldn't be all that surprised to see an increase in heat transfer
efficiency over a gas flame with a plate in between. It probably depends a
lot on the flame gas velocity towards/at the pot.

This all goes to show that the pot is an intergal part of the cooking
experience and a variable of underrated significance in the evaluation of a
stoves performance.

Sincerely
Crispin

From lanny at ROMAN.NET Fri Jun 4 17:57:38 2004
From: lanny at ROMAN.NET (Lanny Henson)
Date: Tue Aug 10 18:31:13 2004
Subject: Heat from radiation v.s. conduction using shiny (real) pots
Message-ID: <FRI.4.JUN.2004.175738.0400.LANNY@ROMAN.NET>

I had not thought about radiant heat reflecting back off of the pot.
I wonder if you could dull, coat or oxide patina the surface?
Good creative thinking, but what do I know :-)
Lanny Henson

----- Original Message -----
From: Crispin Pemberton-Pigott <crispin@newdawn.sz>
To: <STOVES@LISTSERV.REPP.ORG>
Sent: Friday, June 04, 2004 2:40 PM
Subject: [STOVES] Heat from radiation v.s. conduction using shiny (real)
pots

> Dear Stovers
>
> I have been checking out the difference in heat received from radiation
and
> conduction when cooking with ordinary shiny aluminum pots, seeing as that
is
> what people use.
>
> I have hear various figures bandied about with regard to how many times
more
> heat is yielded to the pot when it is radiated instead of conducted either
> from touching a metal surface or from touching hot gases. My thumb-suck
> experiments were somewhat surprising.
>
> First, I went to a pot spinning shop and had them make me a lipped
> handle-less pot 152 deep and 220 in diameter. This I sunk into a small
> downdraft coal stove so that the whole area of the pot was exposed to hot
> gases with passage gaps of about 10mm.
>
> In a regular stove like a Rocket 2-pot with a fire under the first pot
(Pot
> 1) the gases then pass around Pot 2 to pick up heat otherwise wasted.
There
> was a good picture posted some time ago of a stainless steel 2-pot Rocket
> stove with integrated oven. It was at the ETHOS meeting. I have used
that
> particular unit so I had some idea of what it was like and what my stoves
> are like with a similar heat-collection pot.
>
> My plan was to see what happens if the pot is highly polished. It will
tend
> not to pick up radiated heat and then it will tend to keep heat in once it
> gets hold of it because its radiation coefficient is so poor.
>
> Second, I put 5 litres of water into the pot in position 2 (collecting
waste
> heat). This took 33 minutes to come to a vigorous boil. By the time it
did
> the mirror finish was covered with a light dusting of white ash which
wasn't
> all that surprising. I suppose it insulated it a tiny bit. The part of
the
> pot which was not exposed to the front or side of the gas stream remained
> clean and shiny. I suspect that nearly none of the heat that was in the
pot
> radiated away towards the chimney from that 'back' surface. In other
words,
> it was partially self-insulating by being reflective.
>
> Third, I balanced a large (240mm) diameter pot over the fire so that the
> bottom was about 50mm away from the red coals. This was a sanded aluminum
> finish on the bottom with highly polished sides. The idea was to pick up
> heat and boil a small amount of water. It was about 2 litres and boiled
in
> about 11 minutes.
>
> Fourth, I got tired of holding the pot and rested it on two 12mm steel
bars
> spanning the fire. This resulted in a higher boiling rate which
interested
> me as the huge amount of radiated heat was, according what I have heard
> about the effectiveness of radiation, supposed to *way* outweigh the
effect
> of conducted heat from sitting on the thin bar contact area.
>
> Looking in I could see that the boiling was coming not from the bottom
where
> all the radiation hit the pot but from 2 clearly defined lines of bubbles
> corresponding to where it sat on the rods. The water bubbled like crazy
> along those two lines and hardly at all from the rest of the bottom, even
> though it was 50mm from at least 4 to 5 KW of radiant heat. The silvery
> bottom is an effective reflector.
>
> Fifth, I placed over the coals an old battered aluminum pot with a burned
> black bottom (230 mm diameter, 4 litre). It heated far faster than the
new
> pot did, but it still liked the contact with the rods.
>
> Sixth, I placed a black 3mm thick mild steel plate over the fire
(completely
> removing radiation) and put the large pot on top of it. Surprisingly, in
> spite of the shrinking fire it brought 6+ litres of water to a low boil.
I
> expected that would not be possible because of the low power input through
> the plate, however the ability of the pot to retain heat insides its
> polished walls was amazing.
>
> Conclusion: I think this radiated heat business needs a good looking into.
> On the face of it, conduction was a far stronger deliverer of heat to a
> clean aluminum pot than radiation was. If I had used polished stainless
> steel the effect would have been even more pronounced. It is possible
that
> conduction of heat to shiny pots is much more important, perhaps by an
order
> of magnitude, than it has been given credit for. As distance from the
fire
> to the pot is often a 'defining criterion' of stove manuals, it is likely
> that significant changes are needed in the approach to heat transfer
theory
> given in DIY manuals.
>
> This has a lot of interesting implications for people cooking with
paraffin
> (clean burning ones) and charcoal. People like charcoal because it
doesn't
> dirty the pots, but I'll bet they don't know that they should use a black
> plate in between a shiny pot and the fire to save fuel. Perhaps it should
> be perforated. Who knows? Has anyone been looking?
>
> I think this is something everyone should try at home to see what they
find.
> Use a shiny stainless steel pot and put it on a flat black plate over a
gas
> fire, charcoal fire, wood fire and an electric hot plate. I will bet that
> the heat transfer and heat retention when using an electric stove without
a
> plate in between is excellent, and that when using a charcoal fire it
> improves with some form of a plate.
>
> I wouldn't be all that surprised to see an increase in heat transfer
> efficiency over a gas flame with a plate in between. It probably depends
a
> lot on the flame gas velocity towards/at the pot.
>
> This all goes to show that the pot is an intergal part of the cooking
> experience and a variable of underrated significance in the evaluation of
a
> stoves performance.
>
> Sincerely
> Crispin

From rbadhi at YAHOO.COM Fri Jun 4 18:13:33 2004
From: rbadhi at YAHOO.COM (Rajendra Adhikari)
Date: Tue Aug 10 18:31:13 2004
Subject: Flaming Resin For Jumla
Message-ID: <FRI.4.JUN.2004.151333.0700.RBADHI@YAHOO.COM>

Dear Stovers

I am giving below the composition of pine resin usually found in Jumla, Nepal:

The pine species are: (a) Pinus roxburghii and (b) Pinus wallichiana. The oleoresin on distillation yields about 16-20%w/w turpentine oil and 76-80% solid resin.
Gas Liquid chromatography analysis of turpentine oil is roughly as follows:
Hydrocarbons Mol. Formula %
Delta-3-carene C10H16 48.90
Alpha PInene C10H16 27.97
Beta Pinene C10H16 16.07
Para Cymene C10H14 6.83
Gamma Terpinene C10H16 0.23
Limonene C10H16 Trace

May be somebody will find it useful to make smokeless resin lamp.

In Nepal turpentine is costlier than kerosene.

Regards

R. B. Adhikari
<rbadhi@yahoo.com>

---------------------------------
Do you Yahoo!?
Friends. Fun. Try the all-new Yahoo! Messenger

From crispin at NEWDAWN.SZ Fri Jun 4 18:54:38 2004
From: crispin at NEWDAWN.SZ (Crispin Pemberton-Pigott)
Date: Tue Aug 10 18:31:13 2004
Subject: Heat from radiation v.s. conduction using shiny (real) pots
Message-ID: <SAT.5.JUN.2004.005438.0200.>

Dear Lanny

>I had not thought about radiant heat reflecting back
>off of the pot.

You are not alone. The 'books' seem to understand that it is a black
body receiving heat and remaining at a low temperature because of the
water inside.

How's this: heat radiates from any surface after conductive heat has
been picked up. Heat is radiating all over the place all the time. It
radiates off houses and reflects back from trees at night.

The problem is if you make the surface optimized to pick up heat, you
are possibly also losing more than you used to. There is little point
in working hard to pick up more heat if you are going to lose it again.

Now think about this: suppose you make a surface 10 times more effective
at picking up conductive heat from hot gases passing by. And you
accidentally, by chance, increase the radiation coefficient by a factor
of 20. Will it will gain more heat and lose even more? Surely there is
a model to maximize this gain and minimize the loss? Dale Andreatta -
are you busy this weekend?

One thing is for sure, don't polish the bottom of your pots.

Today I received 2 sheets of 3CR12 - 3mm. They are as black as good old
scale-covered mild steel. In fact I wasn't sure they were stainless and
we complained. I suspect these had missed getting into the pickling
bath. They would be far better at picking up heat than the regular
silvery finish.

When you weld stainless steel it goes black on the surface from high
temperature oxidation. It is 'shiny' because it is smooth (even a black
car can be shiny) but it is probably possible to blacken the bottom of a
stainless steel pot with some sort of treatment.

What about gun blue? Low tech electroplating? Hard chroming is pretty
dark. When I made IMAX camera parts back in my youth they were all hard
chromed and are not bright. The case was anodized flat black

Aluminum can be anodized several different colours. Can we anodize the
bottom part of polished aluminum pots flat black? With what? Car
batteries in parallel? Who knows about black anodizing? The solar
cooker pots available in RSA are painted black. Not very satisfactory.

Cooking over wood gives a nice even black finish which will bake on well
if you don't wash it too hard on the outside. How much more effective
is such a pot at picking up and retaining heat?

It seems obvious to me that the pot should sit into the heat shield at
least part way and that part should be black, especially flat/matte
black. Outside it should shine like a mirror to retain the heat.

All this raise another question: should the heat shield be reflective to
send heat radiating from the pot surface back, or black to pick up heat
from the passing gasses and radiate it to the pot? A black heat shield
can get very hot and will re-radiate what comes from the pot, and
accumulate and radiate heat from passing gasses. A shiny silver heat
shield around a shiny silver pot is nearly useless.

Interesting.

Regards
Crispin

From adkarve at PN2.VSNL.NET.IN Fri Jun 4 20:54:45 2004
From: adkarve at PN2.VSNL.NET.IN (adkarve)
Date: Tue Aug 10 18:31:13 2004
Subject: Heat from radiation v.s. conduction using shiny (real) pots
Message-ID: <SAT.5.JUN.2004.062445.0530.ADKARVE@PN2.VSNL.NET.IN>

Bravo Crispin! A fantastic set of experiments. Now we have to discourage
housewives from scrubbing the pots to a shine :-). I always thought that
placing a pot on the Plancha stove would be less efficient than placing the
pot directly on the fire. But your experiments indicate that the hot plate
of the Plancha was just what the doctor ordered, at least in the case of
shiny new pots. Your experiments give a new direction to stove designing.
Yours
A.D.Karve
----- Original Message -----
From: Crispin Pemberton-Pigott <crispin@newdawn.sz>
To: <STOVES@LISTSERV.REPP.ORG>
Sent: Saturday, June 05, 2004 12:10 AM
Subject: [STOVES] Heat from radiation v.s. conduction using shiny (real)
pots

From adkarve at PN2.VSNL.NET.IN Fri Jun 4 21:12:02 2004
From: adkarve at PN2.VSNL.NET.IN (adkarve)
Date: Tue Aug 10 18:31:13 2004
Subject: Tracking unit for parabolic cooker
Message-ID: <SAT.5.JUN.2004.064202.0530.ADKARVE@PN2.VSNL.NET.IN>

The address of the inventor is:
Mr.H.M.Desai
4/39 Municipal Quarters, Government Colony
Race Course, Haji Ali Park, Mumbai 400 034, India
Phone: 91-22-24922763/24902151
Yours A.D.Karve
----- Original Message -----
From: reecon <reecon@mitsuminet.com>
To: <STOVES@LISTSERV.REPP.ORG>
Sent: Friday, June 04, 2004 7:18 PM
Subject: [STOVES] Tracking unit for parabolic cooker

Hallo stovers,
I noticed a poster that said someone had developed a simple tracking device
for parabolic solar cookers, i seem to have deleted it. Could i have that
information please. (Dr. Karve?).
Regards,
Musungu.

From hseaver at CYBERSHAMANIX.COM Sat Jun 5 07:53:45 2004
From: hseaver at CYBERSHAMANIX.COM (Harmon Seaver)
Date: Tue Aug 10 18:31:13 2004
Subject: Absortion chillers using our heat
In-Reply-To: <4.3.1.2.20040603215204.02510cd0@mail.ilstu.edu>
Message-ID: <SAT.5.JUN.2004.065345.0500.HSEAVER@CYBERSHAMANIX.COM>

On Thu, Jun 03, 2004 at 10:29:24PM -0500, Paul S. Anderson wrote:
> Stovers,
>
> Thanks for the responses. From the GASification list serve, I received
> only one main reply, and it sent me to
> http://www.ggw.org/~cac/IcyBall/crosley_icyball.html and at
> http://www.ggw.org/~cac/IcyBall/HomeBuilt/HomeBuilt.html and at
> http://www.fridge.lionheart.net (site of Rich Carey)
>
> From the Stovers, Jeff (message below) had some great info.
>
> NOW my question is, what can be made at LOW cost for developing
> countries? I am thinking of cool, not cold, (to freeze water would be
> nice, but that is not as important as cool so that milk, etc does not
> spoil.)

That icy-ball design, or modifications of it, is probably about as cheap as
you can get. Of course there's always the "swamp cooler" using water soaked
burlap over a box if you just want cool, also root cellars keep milk cool
enough, or did for us for many years.
You could even make a solar powered version of the icyball, even create
air-conditioners with them.

--
Harmon Seaver
CyberShamanix
http://www.cybershamanix.com
Hoka hey!

From kgoyer at COMCAST.NET Sat Jun 5 16:33:27 2004
From: kgoyer at COMCAST.NET (ken goyer)
Date: Tue Aug 10 18:31:13 2004
Subject: [ethos] Bricks from Ken Goyer
In-Reply-To: <BCE4F327.3CC2%solar1@zuper.net>
Message-ID: <SAT.5.JUN.2004.133327.0700.KGOYER@COMCAST.NET>

Dear Friends, If the brick is particularly weak or won't hold together
when fired it is probably the fault of the clay. All clays are not
equal. Brick makers should know their clay body and how to adjust it. If
you don't have the luxury of someone else's experience then making
experiments is the best way to find out. Good clay has certain well
known properties which vary depending on the use that you have in mind.
Fortunately, our ceramics are very forgiving of much of the criteria
that potters expect.. We don't care what color it becomes when fired or
how thin you can turn it on a wheel. If you can make a ball of wet clay
in your hand and it sticks together, that is a good sign. If you can
drop the ball to the ground and it flattens but doesn't splatter, that
is a good sign. Many other tests can be performed to determine it's
shrinkage and firing point etc. These tests are described in most
beginning pottery books.
Clay can be improved by processing if necessary. One method would be
to stir up a pond of clay with a beast (an animal like a horse or oxen).
The mud that goes into suspension is decanted off to another pond where
it is allowed to settle. This way sand and other impurities are removes
and the smaller clay particles are hi-graded. Potters sometimes use a
barrel with a motor driven propeller to stir up a slurry of clay
allowing heavies to settle and then drain off the fine particles into
another barrel. But this will not produce enough clay for a high
production operation. The best solution is to find a good clean clay
body sufficient for your needs for a long time.
I don't understand why your bricks won't dry, unless it's raining
all of the time or the humidity is extremely high. I have never had
drying problems when using sawdust. I have had drying problems when
using paper, newspaper, cardboard, flour, and some types of ground up
vegetables. I like to use cement in a brick. The brick will harden in a
day and then it can be handled and turned so more sides are exposed to
the air. Also the brick will shrink less. I have made many successful
bricks with no cement as well. It might take a brick a week to dry
completely. Here in Oregon in the rainy season (most of the time) I like
to dry bricks indoors. Often times, due to lack of patience, we are
trying to fire wet bricks. If you proceed very slowly this seems to
work. The brick is force dried and then the temperature is raised to
burn out the organic matter and so on.
The important thing is that you keep on experimenting and eventually
the solution will appear. Keep asking questions too! Best of luck! Ken
Goyer

From yark at UIUC.EDU Sat Jun 5 18:59:47 2004
From: yark at UIUC.EDU (Tami Bond)
Date: Tue Aug 10 18:31:13 2004
Subject: which emission is more important measuring
In-Reply-To: <pbg9a05qbfcr1mmpshiibur0925k6sr01t@4ax.com>
Message-ID: <SAT.5.JUN.2004.175947.0500.YARK@UIUC.EDU>

Hello friends,

Sorry to chime in late. I have been out of town too much, and the
discussion got really 'hot' after I left... Guess I should go out more...

Anyway, we have settled on measuring CO and particulate matter (PM). We
also measure CO2 but not for global warming purposes-- just to get the
emissions per fuel burned. CH4 is not a major emission, and I think NOx
isn't either (combustion too cold). SO2 depends on fuel sulfur content--
probably not worth worrying about. The next step up would be measuring way
more fancy stuff such as components of the particles or unburned gas
hydrocarbons.

Any disagreements?

There are some of my presentations at the last 3 years ETHOS meetings at:
http://cee.uiuc.edu/research/bondresearch/stoves.html
...under 'Small Contributions'
These are big files, sorry. If you have a slow connection let me know and I
will try to strip out the graphics so the files are smaller.

CO and particles might be correlated under some conditions and not under
others. As others have said, charcoal might put out more CO and less PM.

Kanchan wrote:
>I like to measure particle emissions for my stove testing
>in Kathmandu University. But don't know how as I couldnot afford to
>setup laboratory the kind how people measure this thing. Some body could
>suggest easy and cost effective way?

At this point there is NOT an easy way to measure particulate matter. I
have looked, a lot. But maybe you could tell us what is 'affordable' for a
university like yours.

Kirk Smith is working on a particle measurement package, which will be
available sometime. And we are trying to get a relatively inexpensive setup
installed at Aprovecho, but I think it is still expensive by Kathmandu
standards. My hope is that by iterating with testing places that are close
by us (like Apro) we can work out the bugs of what we have proposed. Then
we eventually come up with something workable for universities who are less
well funded overseas.

We are also setting up one of these university labs of skeptical value
(wink, AJH) and the idea is to compare the results from fancy equipment
with cheaper equipment to determine just how cheap we can go, and still be
useful to stovers like you.

Andrew wrote:
>I think you could do comparative tests by sucking a known volume of
>air through a tissue of fixed cross section. Then you can look at the
>dark disc formed by the particulates.

Das and I have a disagreement on this-- he thinks smoke shade is okay, I
don't. I don't like smoke shade because some of the particles from wood
combustion aren't black, so there's not a great relationship between total
mass and color.

cheers
Tami

From Kanchan at KU.EDU.NP Sun Jun 6 09:29:38 2004
From: Kanchan at KU.EDU.NP (Kanchan Rai)
Date: Tue Aug 10 18:31:13 2004
Subject: [ethos] Bricks from Ken Goyer
Message-ID: <SUN.6.JUN.2004.191438.0545.KANCHAN@KU.EDU.NP>

Dear goyer,
thanks for providing information on clay and bricks. Could you tell me
what kind of kiln are you using for baking bricks, how long do you bake
at what temperature?

kanchan

> Dear Friends, If the brick is particularly weak or won't hold
> together when fired it is probably the fault of the clay. All clays
> are not equal. Brick makers should know their clay body and how to
> adjust it. If you don't have the luxury of someone else's experience
> then making experiments is the best way to find out. Good clay has
> certain well known properties which vary depending on the use that you
> have in mind. Fortunately, our ceramics are very forgiving of much of
> the criteria that potters expect.. We don't care what color it becomes
> when fired or how thin you can turn it on a wheel. If you can make a
> ball of wet clay in your hand and it sticks together, that is a good
> sign. If you can drop the ball to the ground and it flattens but
> doesn't splatter, that is a good sign. Many other tests can be
> performed to determine it's shrinkage and firing point etc. These
> tests are described in most beginning pottery books.
> Clay can be improved by processing if necessary. One method would
> be
> to stir up a pond of clay with a beast (an animal like a horse or
> oxen). The mud that goes into suspension is decanted off to another
> pond where it is allowed to settle. This way sand and other impurities
> are removes and the smaller clay particles are hi-graded. Potters
> sometimes use a barrel with a motor driven propeller to stir up a
> slurry of clay allowing heavies to settle and then drain off the fine
> particles into another barrel. But this will not produce enough clay
> for a high production operation. The best solution is to find a good
> clean clay body sufficient for your needs for a long time.
> I don't understand why your bricks won't dry, unless it's raining
> all of the time or the humidity is extremely high. I have never had
> drying problems when using sawdust. I have had drying problems when
> using paper, newspaper, cardboard, flour, and some types of ground up
> vegetables. I like to use cement in a brick. The brick will harden in
> a day and then it can be handled and turned so more sides are exposed
> to the air. Also the brick will shrink less. I have made many
> successful bricks with no cement as well. It might take a brick a week
> to dry completely. Here in Oregon in the rainy season (most of the
> time) I like to dry bricks indoors. Often times, due to lack of
> patience, we are trying to fire wet bricks. If you proceed very slowly
> this seems to work. The brick is force dried and then the temperature
> is raised to burn out the organic matter and so on.
> The important thing is that you keep on experimenting and
> eventually
> the solution will appear. Keep asking questions too! Best of luck!
> Ken Goyer

From Kanchan at KU.EDU.NP Sun Jun 6 09:30:27 2004
From: Kanchan at KU.EDU.NP (Kanchan Rai)
Date: Tue Aug 10 18:31:13 2004
Subject: [ethos] Bricks from Ken Goyer
Message-ID: <SUN.6.JUN.2004.191527.0545.KANCHAN@KU.EDU.NP>

Dear ken goyer,
thanks for providing information on clay and bricks. Could you tell me
what kind of kiln are you using for baking bricks, how long do you bake
at what temperature?

kanchan

From crispin at NEWDAWN.SZ Sun Jun 6 09:59:28 2004
From: crispin at NEWDAWN.SZ (Crispin Pemberton-Pigott)
Date: Tue Aug 10 18:31:14 2004
Subject: Heat from radiation v.s. conduction using shiny (real) pots
Message-ID: <SUN.6.JUN.2004.155928.0200.>

Dear Dr AD

>Now we have to discourage housewives from
>scrubbing the pots to a shine

Quite so. I am not sure where the scrubbing should stop, but perhaps we
need to look carefully at pot heat acquisition and retention.

>I always thought that placing a pot on the Plancha
>stove would be less efficient than placing the pot
>directly on the fire.

It probably is of the pot is battered. I was doing something that was
going to show the influence of a reflective surface as I feel the
subject is barely explored. Certainly nothing can be concluded in
general just yet.

>But your experiments indicate that the hot
>plate of the Plancha was just what the doctor
>ordered, at least in the case of shiny new pots.

Yes. I have wondered about a black copper disk under new pots. I
encourage everyone to try this experiment and see what results they get.
Surely there will be some conflicting results which need to be discussed
until we find a more efficient set of hardware.

Suppose, for example, a No. 2 (nine litre) 3-legged pot were to be
inverted in a plating plant and chromed from the top lip down to the
midline. This may prevent a huge amount of energy from radiating from
the upper charcoal-black, rough, cast iron surface. And the lid too for
that matter. The bottom should be left black to pick up heat, the top
chromed to retain it.

What would be the maximum efficiency of a three stove fire when using
such a pot? Surely it would be above the 33% figure Piet Visser got
with his 'little-at-a-time' woodshaving-feeding experiments? That is
why I keep mentioning the device-dependant nature of experimental
results.

>Your experiments give a new direction to stove designing.

Well I agree with the assessment.

I have written separately to Tami and Dr Prasad about the possiblity
that the way in which heat shields work is not clear and also the
possible over-rating of the effect of surface 'scrubbing' in the
pot-to-heat shield gap.

In very brief, if the heat shield is black, not shiny, is more heat
transferred from the passing gas stream because the heat shield is able
to radiate (by conversion) conductive heat directly to the pot a few mm
away? If it is shiny and picks up hear from physical contact with
shaking molecules of gas, and from radiating molecules and from the
re-radiating pot surface, how will it radiate that heat over to the pot?
The heat shield will get very hot but it will not be able to 'send' it
to the pot if it is shiny.

If we believe that only scrubbing is involved in assisting heat transfer
from the gas stream to the pot, then the heat shield is primarily there
to bring that gas stream into high velocity contact with the pot. If we
accept that the heat shield is itself a potent radiator of conductive
heat gathered from the passing gas stream, a radiator which is
inherently higher in temperature than the water-cooled pot, one may
indeed take a different approach to stove construction.

For example - should the lower part of the heat shield be jet-black and
the upper part chromed? This is to convert as much heat as possible
from the convecting gases into radiated heat aimed at the pot. At some
point as the gases cool, the effectiveness of this conversion to
radiation drops to a point at which there should rather be a highly
reflective surface to reflect heat radiating from passing hot molecules
and re-radiation from the pot surface towards the pot. Where is this
dividing line?

Simlarly, at some point, a pot should change from an absorbtive to a
retentive coating or finish.

The pot is part of the stove.

Regards
Crispin

From list at SYLVA.ICUKLIVE.CO.UK Sun Jun 6 17:22:36 2004
From: list at SYLVA.ICUKLIVE.CO.UK (Andrew Heggie)
Date: Tue Aug 10 18:31:14 2004
Subject: use of outside air with analysis KR
In-Reply-To: <40514.202.52.242.69.1085942037.squirrel@webmail.ku.edu.np>
Message-ID: <SUN.6.JUN.2004.222236.0100.>

On Mon, 31 May 2004 00:18:57 +0545, Kanchan Rai wrote:

>For the passage of air on the ground might be insulated using locally
>available material. A tree called silver porch is available in that
>area, which has a paper like layers which is very good insulator. People
>use such thing to insulate their roof.

Kanchan, this sounds like silver birch, the betula family,
characterised by an oily bark which finds many uses (canoes in the US)
>
>>
>> So your numbers need to reflect the planned air changes for that size
>> of room and the number of occupants as well.
>
>How much do you suggest the air changes for the room of size 10 feet *
>12 feet with 8 feet height when burning rate is 2kg/hr ?

We may be talking at cross purposes here, I was meaning air changes
for the comfort and health of the occupants, which I felt was best
incorporated into the combustion air, I've come back to nearly 100
messages on Stoves (well done all) so I will take a while to catch up,
I shall see what the recommended air changes are for a kitchen in UK.

AJH

From list at SYLVA.ICUKLIVE.CO.UK Sun Jun 6 17:22:35 2004
From: list at SYLVA.ICUKLIVE.CO.UK (Andrew Heggie)
Date: Tue Aug 10 18:31:14 2004
Subject: Flames for lighting
In-Reply-To: <7vlbb0lptklhlav7mge0l0eaot5ajf7s2l@4ax.com>
Message-ID: <SUN.6.JUN.2004.222235.0100.>

On Thu, 27 May 2004 13:25:14 +0100, Peter Verhaart wrote:
>I have changed the thread name to see if we can continue the
>discussion of this aspect, I think it is still relevant to stoves even
>though no longer relevant to cooking.
>On Thu, 27 May 2004 09:45:20 +1000

Snip

>Anyone care to elaborate on what and how these nasties are formed,
>currently I believe they are PICs formed when a hydrogen atom finds an
>oxygen atom preferentially to the remaining carbon compound it split
>from. So it is basically a lack of oxygen but why is it that this
>sooty particle, probably with some nasty aromatic compound attached to
>it, becomes so difficult to burn out? because the benzene ring, of the
>attached aromatic is a stable one?

I think polycyclic compounds are even more stable, like PCB's .

> >Before you or I were even thought of, people burned aethyn (acetylene) for

>As you say an un premixed acetylene flame is very sooty, does it have
>any especial luminance advantage over a candle flame? Definitely as
>you add oxygen in the premix it firstly goes a brighter white before
>the stable two cones of pale blue flame at stoichiometric mix.

The acetylene flame is much hotter than the flame of straight chain
alkanes
because of the heat of dissociation of C2H2. This results in a much
brighter flame and if it can be kept small enough it will not soot.
Acetylene on the least provocation dissociates into, not surprisingly,
hydrogen and carbon and quite a lot of heat. Added to this the heat of
combustion of the hydrogen and some of the carbon and you have a
bright
almost white flame.

>As to the small flame having better surface area I note that if you
>light a single sheet of polythene it burns both cleanly and with a
>bluish flame, put fire to a lot of polythene sacks and the result is a
>smoky yellow flame.

Between the single sheet and a lot of sacks there should be a luminous
flame without soot or visible smoke.

From list at SYLVA.ICUKLIVE.CO.UK Sun Jun 6 17:24:01 2004
From: list at SYLVA.ICUKLIVE.CO.UK (Andrew Heggie)
Date: Tue Aug 10 18:31:14 2004
Subject: Flaming Resin For Jumla
In-Reply-To: <20040604221333.59898.qmail@web41606.mail.yahoo.com>
Message-ID: <SUN.6.JUN.2004.222401.0100.>

On Fri, 4 Jun 2004 15:13:33 -0700, Rajendra Adhikari wrote:

>Dear Stovers
>
>I am giving below the composition of pine resin usually found in Jumla, Nepal:
>
>The pine species are: (a) Pinus roxburghii and (b) Pinus wallichiana.

Rajendra, for the record the species I tapped was Pinus sylvestris.

>The oleoresin on distillation yields about 16-20%w/w turpentine oil and 76-80% solid resin.

What temperatures are used for distillation? In my time away the small
amount I collected has solidified into a crumbly resin, do I take it
this means these (valuable) volatile fractions have evaporated away?

>Gas Liquid chromatography analysis of turpentine oil is roughly as follows:
>Hydrocarbons Mol. Formula %
>Delta-3-carene C10H16 48.90
>Alpha PInene C10H16 27.97
>Beta Pinene C10H16 16.07
>Para Cymene C10H14 6.83
>Gamma Terpinene C10H16 0.23
>Limonene C10H16 Trace
>
>May be somebody will find it useful to make smokeless resin lamp.
>
>In Nepal turpentine is costlier than kerosene.

In which case as Kevin suggested it may better be collected as a cash
crop and the remaining resin concentrated on for lighting, mind I feel
the LED approach may be more benefit.

Thanks for the chemical analysis.

AJH

From list at SYLVA.ICUKLIVE.CO.UK Sun Jun 6 17:24:01 2004
From: list at SYLVA.ICUKLIVE.CO.UK (Andrew Heggie)
Date: Tue Aug 10 18:31:14 2004
Subject: which emission is more important measuring
In-Reply-To: <6.0.1.1.2.20040605173811.01f1e8e0@express.cites.uiuc.edu>
Message-ID: <SUN.6.JUN.2004.222401.0100.>

On Sat, 5 Jun 2004 17:59:47 -0500, Tami Bond wrote:

>Hello friends,
>
>Sorry to chime in late. I have been out of town too much, and the
>discussion got really 'hot' after I left... Guess I should go out more...

Tell me about it...

Still better late than never, thanks.

>There are some of my presentations at the last 3 years ETHOS meetings at:
>http://cee.uiuc.edu/research/bondresearch/stoves.html

Another one for my "to do" list ;-)

>
>We are also setting up one of these university labs of skeptical value
>(wink, AJH) and the idea is to compare the results from fancy equipment
>with cheaper equipment to determine just how cheap we can go, and still be
>useful to stovers like you.

OK you misquote me slightly, I am skeptical of the cost benefit of
work done in UK universities compared with the workers on the ground
doing practical work, based on being "burnt" here, fundamental
research is a different matter.

Anyway over to the workers in Nepal now Tami has asked the 64 dollar
question....

>
>Andrew wrote:
>>I think you could do comparative tests by sucking a known volume of
>>air through a tissue of fixed cross section. Then you can look at the
>>dark disc formed by the particulates.
>
>Das and I have a disagreement on this-- he thinks smoke shade is okay, I
>don't. I don't like smoke shade because some of the particles from wood
>combustion aren't black, so there's not a great relationship between total
>mass and color.

Thanks that's well worth considering.

AJH

From list at SYLVA.ICUKLIVE.CO.UK Sun Jun 6 17:24:02 2004
From: list at SYLVA.ICUKLIVE.CO.UK (Andrew Heggie)
Date: Tue Aug 10 18:31:14 2004
Subject: Heat from radiation v.s. conduction using shiny (real) pots
In-Reply-To: <000001c44a86$ee549450$e49dfea9@home>
Message-ID: <SUN.6.JUN.2004.222402.0100.>

On Sat, 5 Jun 2004 00:54:38 +0200, Crispin Pemberton-Pigott wrote:

>Dear Lanny
>
>>I had not thought about radiant heat reflecting back
>>off of the pot.
>
>You are not alone. The 'books' seem to understand that it is a black
>body receiving heat and remaining at a low temperature because of the
>water inside.

Crispin, I am too way behind to catch up on all this, I still have 44
unread stoves messages, so I'll just add a few further points and
maybe pick up on your specific ones later. I'm not a teacher and I may
well be wrong, I am willing to play Aunt Sally to provoke a bit of
discussion, though this was going well enough before I returned.

Firstly I am sure most heat transfer in domestic cooking stoves takes
place via convection and conduction. However in industry the opposite
is often the case, this is caused by a number of factors, not least of
which is that industrial scale burning takes place as near to
stoichiometric as possible, so the flame temperatures are much higher,
as radiation effects are related to the fourth power of the absolute
temperature you can see how a 2200K flame can emit a lot of radiative
power compared with a 900K wood stove.

Another point is that reflectivity and emissivity are two different
physical properties, so a good reflector may also radiate its heat
away. Also I agree your point that the angle subtended by the pot
looking at the flame is less than the angle through which the pot can
radiate away its heat, so again the radiation effect is asymmetrical
BUT the pot is at a lower temperature (normally <370K) so it emits
radiation at a less energetic wavelength than the fire.

AJH

From larencorie at AXILAR.NET Sun Jun 6 13:38:08 2004
From: larencorie at AXILAR.NET (LarenCorie)
Date: Tue Aug 10 18:31:14 2004
Subject: Heat from radiation v.s. conduction using shiny (real) pots
Message-ID: <SUN.6.JUN.2004.133808.0400.LARENCORIE@AXILAR.NET>

Crispin Pemberton-Pigott <crispin@NEWDAWN.SZ> wrote;

> How's this: heat radiates from any surface after conductive heat has
> been picked up. Heat is radiating all over the place all the time. It
> radiates off houses and reflects back from trees at night.

It doesn't reflect back from trees very much.
Trees are seldom warmer, and absorb infrared quite well.

> The problem is if you make the surface optimized to pick up heat,

Absorb.

> you are possibly also losing more than you used to.

Emit

> There is little point in working hard to pick up more heat
> if you are going to lose it again.

> Now think about this: suppose you make a surface 10 times more
> effective at picking up conductive heat from hot gases passing by.

The is not "conduction." That is "convection"

It can be increased by increasing 1) surface area (relative
to the gas interface. 2) velocity of the gas over the surface,
thereby reducing the Rvalue of the surface film.

> And you accidentally, by chance, increase the radiation
> coefficient by a factor of 20.

That would be impossible. Very shiny polished metal only
has an emissivity of about .05 20 time that would 1, or
the emissivity of a "perfect black body" a perfect emitter.

> Will it will gain more heat and lose even more?
> Surely there is a model to maximize this gain and
> minimize the loss?

That basic problem is that the temperature you wish to absorb,
and the temperature that you wish to not emit, are very similar.
Therfore their wavelength is also very similar. There are selective
surfaces, which function very well to distingush the difference
between visible light, and log wave length infrared. IIRC they
are in the range of about 20 microns or 1/10,000 inch. (might
be off) Anyway, it is relatively easy to make a surface that will
absorb light very well (up to 96%) yet have an emissivity as
low as even 6%. However, such a surface cannot be exposed
to any amount of particulates, or the surface quickly becomes
fouled, and loses its low emissivity. As a result, cheaper, less
selective surfaces are more popular. Not only are selective
surfaces used on solar collector absorbers, but they are even
more poplar as glass coating. The "E" in Lo-E glass stand for
"emissivity" It is a very then layer of metal (copper based
I believe) that is sputtered out onto the glass, so thinly that
it can be seen through. There is also selectivity in paints.
Laquers tend to emit less than the same color enamels or
acrylics. There are special low emissivity paints with
Es as low as 0.4. White is an interesting color. It can
absorb as little as 10% of visible light, yet still emit
basically as well as any other color, like a black that
absorb 95% of the visible light. Again, this works
because of the great difference in wavelength between
visible light and the long wave length, relatively cool,
infrared that is emitted in livable human environments.
We may think a gasifier gets hot, but the sun it is not.
The pot surface is about the same temperature as the
gas, and it is too easy to foul, so a selective surface
is not practical.

> One thing is for sure, don't polish the bottom of your pots.

That really depends. Since it is not possible to be selective
about the gains from radiation, or even convection, then we
must look to the option of conductive gain. If we can bring
the heat to the pot via direct contact with a hot object, then
the super low emissivity of the polished surface will help it
to retain the heat and get much hotter before reaching
equalibrium. Notice how much hotter a piece of polished
metal will get, out in the sun, than one that is painted white,
even though the white one will be absorbing about twice
as much energy. The white one, however, emits at a rate that
is as much as 18 times greater than the polished surface.
It you can get the heat into the pot, it will stay there far
better, if the pot is polished.

So, We want to.......

1) absorb radiant energy into a burner
2) absorb into the burner via convection
3) transfer the heat from the burner to the pot via conduction.
4) reduce radiant heat loss from the pot via a polished surface
5) reduce convective heat loss from the pot
6) perhaps reduce evaporative heat loss from the pot contents

> Today I received 2 sheets of 3CR12 - 3mm. They are as black
> as good old scale-covered mild steel. In fact I wasn't sure they
> were stainless and we complained. I suspect these had missed
> getting into the pickling bath. They would be far better at
> picking up heat than the regular silvery finish.

Just in absorbing radiation.

> When you weld stainless steel it goes black on the surface from
> high temperature oxidation. It is 'shiny' because it is smooth
> (even a black car can be shiny) but it is probably possible to
> blacken the bottom of a stainless steel pot with some sort of
> treatment.

Surfaces like that sometimes are in the right thickness range
to exhibit selective radiation properties. Black chrome is a
very popular selective surface for solar collectors. It is also
used on things like cameras and furniture. Black chrome
furniture can be literally dangerous in the sun. It can
reach temperatures high enough to cause injury.

> What about gun blue?

There would doubtfully be no advantage. There is no selectivity.

> Low tech electroplating? Hard chroming is pretty dark.
> When I made IMAX camera parts back in my youth they
> were all hard chromed and are not bright. The case was
> anodized flat black

Again, it is possible to control the process to the point where
the surface can distiguish between the tiny wavelength of
visible light, and the long wavelength of fairly cool infrared,
but it is not going to be able to tell the difference between
the flame and the pot. Even if it could the exposed surface
would very quickly become fouled, and lose its selectivity.

> Aluminum can be anodized several different colours. Can
> we anodize the bottom part of polished aluminum pots flat
> black?

Using a polish surface on the sides, and a colored surface on
the bottom is a good idea. It need not be black. We are not
dealing with enough visible light for that to matter. It could
be blue, or red, or green, or gray. They all absorb and emit
IR basically the same. I like this idea of "selective orientation"
It is sort of like bonding the "burner" I referred to above,
permanently to the bottom of the pot. I am pretty sure that
there are pans on the market that use a rough cast dark surface
on the bottom, that even has veins to increase turbulence, as
well as surface are, then the sides are polished. Good design.

> With what? Car batteries in parallel? Who knows about
> black anodizing?

Perhaps the bottom should not be polished, but cast with a
rough finish. That would increase the heat exchanger surface
area, but may capture a thin film of dead air, which might
reduce heat flux, however the orientation of the pot above
the heat source, plus the degree of convection should be
able to break up most any surface film. This get complicated.
I can not even venture a good guess as to the optimal degree
of surface texture. It needs empirical testing.

> The solar cooker pots available in RSA are painted black.
> Not very satisfactory.

It is an interesting thought, that they might be more efficient
with the side toward the reflector colored black, and the side
facing the sun, which would not have the concentration, as a
polished surface. It would reflect back the direct sunlight,
but it would also reduce the emissision, from that front
surface (50% view factor), by as much as 90%, so it
would have a higher net gain/loss ratio, and would be
able to hit higher temperatures. Lose a litte, gain a
little more.

> Cooking over wood gives a nice even black finish
> which will bake on well if you don't wash it too
> hard on the outside. How much more effective
> is such a pot at picking up and retaining heat?

Isn't it nice, that things happen so naturally, if you just
let them ;O) Of course the sides can also get covered
with soot too, Don't wash those pans ;O)

> It seems obvious to me that the pot should sit into the
> heat shield at least part way and that part should be black,
> especially flat/matte black. Outside it should shine like a
> mirror to retain the heat.

Yes

> All this raise another question: should the heat shield be
> reflective to send heat radiating from the pot surface back,
> or black to pick up heat from the passing gasses and radiate
> it to the pot?

It depends on which is hotter. It can be said that heat only
moves in one direction, toward cold. If it is hotter than the
pot, it is by definition, not a shield, and if it is really a shield,
then it will serve its function better if it is also a radiant
shield, so polished.

> A black heat shield can get very hot and will re-radiate what
> comes from the pot,

Re-radiate to what?
Black is not a factor. It will function the same in any color.
This is the IR spectrum. Polished is not a color.

> and accumulate and radiate heat from passing gasses.

Yes. It will not function as a heat shield if it is hoter than the pot.
It will also convect and radiate much heat from its exterior side,
unless it is insulated.

> A shiny silver heat shield around a shiny silver pot is
> nearly useless.

It is at least redundant, when they are new. A 95%
reduction, of a 95% reduction is hardly worthwhile.
However, in the real world of cooking polished
surfaces get fouled, which happens extremely easily.
When they do, they lose most of their effectiveness,
and a backup polished surface is a very good idea.

> Interesting.

Very........great subject, and discussion. this is fun ;O)

-Laren Corie-
Passive Solar Building Design Since 1975 (retired)

From list at SYLVA.ICUKLIVE.CO.UK Sun Jun 6 18:13:44 2004
From: list at SYLVA.ICUKLIVE.CO.UK (Andrew Heggie)
Date: Tue Aug 10 18:31:14 2004
Subject: Lights--especially CFL
In-Reply-To: <20040601221536.38458.qmail@web41111.mail.yahoo.com>
Message-ID: <SUN.6.JUN.2004.231344.0100.>

On Tue, 1 Jun 2004 15:15:36 -0700, David Neeley wrote:

>
>All of which said, if you can produce sufficient
>electricity from the stoves, I would completely agree that
>a CFL that runs on the current produced would be the most
>cost-efficient light source available today.

This is my take, the high frequency CFL is the most electricity
efficient at domestic lighting levels.
>
>In my opinion, LED lights are best where portability or
>very long life are more important than individual cost.

Which just goes to illustrate that there is more in the total life
cost than energy efficiency alone.

>Thus, traffic signals, automotive brake lights,
>flashlights, and similar applications are becoming very
>popular.

OK this is a special case where the LED has the advantage of
outputting light at the required frequency (colour), most other
(rapidly switching) lights would require a colour filter which
effectively block light, thus reducing the lumens leaving the device
for the input wattage.

AJH

From dstill at EPUD.NET Sun Jun 6 18:28:05 2004
From: dstill at EPUD.NET (Dean Still)
Date: Tue Aug 10 18:31:14 2004
Subject: Bricks from Ken Goyer
In-Reply-To: <58888.202.52.242.69.1086528578.squirrel@webmail.ku.edu.np>
Message-ID: <SUN.6.JUN.2004.152805.0700.DSTILL@EPUD.NET>

Dear Kanchan Rai,

Ken is off to Ghana to help with a stove project. We give the bricks to
local brick makers who usually fire for a day at around 850 to 1050C. These
are wood or trash burning kilns.

Best,

Dean

From kgoyer at COMCAST.NET Sun Jun 6 19:50:27 2004
From: kgoyer at COMCAST.NET (ken goyer)
Date: Tue Aug 10 18:31:14 2004
Subject: [ethos] Bricks from Ken Goyer
In-Reply-To: <59094.202.52.242.69.1086528627.squirrel@webmail.ku.edu.np>
Message-ID: <SUN.6.JUN.2004.165027.0700.KGOYER@COMCAST.NET>

Dear Kachan, I started making ceramics test pieces and bricks using an
electric kiln such as potters use. At first, I fired very slowly to
eliminate water and burn out organic matter and then raised the
temperature faster. Usually I took about twelve hours to reach 1050 oC
or cone 03. Now I am amazed to discover that just about anything you do
to fire bricks works as long as you can get them to be red hot. Even if
you go fast. I'm sorry that I don't have the time right now to post some
pictures of kilns that have worked. Like I said, I am amazed, almost any
contained space to which you can apply heat long enough seems to work.
The economy of scale with bricks is in making thousands of them at once.
Best regards, Ken Goyer

Kanchan Rai wrote:

>Dear ken goyer,
>thanks for providing information on clay and bricks. Could you tell me
>what kind of kiln are you using for baking bricks, how long do you bake
>at what temperature?
>
>kanchan
>
>
>
>>Dear Friends, If the brick is particularly weak or won't hold
>>together when fired it is probably the fault of the clay. All clays
>>are not equal. Brick makers should know their clay body and how to
>>adjust it. If you don't have the luxury of someone else's experience
>>then making experiments is the best way to find out. Good clay has
>>certain well known properties which vary depending on the use that you
>>have in mind. Fortunately, our ceramics are very forgiving of much of
>>the criteria that potters expect.. We don't care what color it becomes
>>when fired or how thin you can turn it on a wheel. If you can make a
>>ball of wet clay in your hand and it sticks together, that is a good
>>sign. If you can drop the ball to the ground and it flattens but
>>doesn't splatter, that is a good sign. Many other tests can be
>>performed to determine it's shrinkage and firing point etc. These
>>tests are described in most beginning pottery books.
>> Clay can be improved by processing if necessary. One method would
>>be
>>to stir up a pond of clay with a beast (an animal like a horse or
>>oxen). The mud that goes into suspension is decanted off to another
>>pond where it is allowed to settle. This way sand and other impurities
>>are removes and the smaller clay particles are hi-graded. Potters
>>sometimes use a barrel with a motor driven propeller to stir up a
>>slurry of clay allowing heavies to settle and then drain off the fine
>>particles into another barrel. But this will not produce enough clay
>>for a high production operation. The best solution is to find a good
>>clean clay body sufficient for your needs for a long time.
>> I don't understand why your bricks won't dry, unless it's raining
>>all of the time or the humidity is extremely high. I have never had
>>drying problems when using sawdust. I have had drying problems when
>>using paper, newspaper, cardboard, flour, and some types of ground up
>>vegetables. I like to use cement in a brick. The brick will harden in
>>a day and then it can be handled and turned so more sides are exposed
>>to the air. Also the brick will shrink less. I have made many
>>successful bricks with no cement as well. It might take a brick a week
>>to dry completely. Here in Oregon in the rainy season (most of the
>>time) I like to dry bricks indoors. Often times, due to lack of
>>patience, we are trying to fire wet bricks. If you proceed very slowly
>>this seems to work. The brick is force dried and then the temperature
>> is raised to burn out the organic matter and so on.
>> The important thing is that you keep on experimenting and
>>eventually
>>the solution will appear. Keep asking questions too! Best of luck!
>>Ken Goyer
>>
>>
>
>
>
>
>
>

From dbneeley at YAHOO.COM Sun Jun 6 20:37:05 2004
From: dbneeley at YAHOO.COM (David Neeley)
Date: Tue Aug 10 18:31:14 2004
Subject: Heat from radiation v.s. conduction using shiny (real) pots
In-Reply-To: <200406060400.i56400728440@ns1.repp.org>
Message-ID: <SUN.6.JUN.2004.173705.0700.>

Crispin's account was fascinating. However, I have one
question. In his conclusion:

"Conclusion: I think this radiated heat business needs a
good looking into.
"On the face of it, conduction was a far stronger deliverer
of heat to a clean aluminum pot than radiation was. If I
had used polished stainless steel the effect would have
been even more pronounced. It is possible
that conduction of heat to shiny pots is much more
important, perhaps by an order of magnitude, than it has
been given credit for."

Why do you think the polished stainless would have an "even
more pronounced effect" than the aluminum pot?

I presume you assume the more reflective surface would
absorb less radiant heat...and with that I would agree.

However, aluminum is a superior *conductor* of heat to
stainless steel...so perhaps the difference would not be as
substantial as you may assume?

As for radiant heat, I think the conclusion should not be
so surprising. Solar cookers have long used black pots for
this very reason...the solar energy hits the black pot and
its wavelength is changed to heat.

Perhaps the best solution within a fairly reasonable cost
might be a black-anodized aluminum pot--to get the best of
both worlds of radiation and convection.

Regards,

David

__________________________________
Do you Yahoo!?
Friends. Fun. Try the all-new Yahoo! Messenger.
http://messenger.yahoo.com/

From takeda at SONIC.NET Sun Jun 6 20:48:41 2004
From: takeda at SONIC.NET (Matthew Takeda)
Date: Tue Aug 10 18:31:14 2004
Subject: Absortion chillers using our heat
Message-ID: <SUN.6.JUN.2004.174841.0700.TAKEDA@SONIC.NET>

Paul S. Anderson wrote:
>NOW my question is, what can be made at LOW cost for developing
>countries? I am thinking of cool, not cold, (to freeze water would be
>nice, but that is not as important as cool so that milk, etc does not spoil.)

Paul -

Have you looked into intermittent zeolite sorption cooling?

<http://www.eg-solar.de/english/products/solarrefrig.htm>
<http://193.175.120.23/an/pt/solar/publish/euros-00.pdf>

Matthew Takeda
the JOAT
From tmiles at TRMILES.COM Sun Jun 6 23:32:43 2004
From: tmiles at TRMILES.COM (Tom Miles)
Date: Tue Aug 10 18:31:14 2004
Subject: [ethos] Bricks from Ken Goyer
Message-ID: <SUN.6.JUN.2004.203243.0700.TMILES@TRMILES.COM>

Kanchan Rai

Use the "FIND" search on the stoves web page. Of the 53 links some will be helpful. I can tell that we need to do a good section on kilns.

Regards,

Tom Miles
http://www.repp.org/discussiongroups/resources/stoves/
----- Original Message -----
From: ken goyer
To: Kanchan Rai ; STOVES@LISTSERV.REPP.ORG ; ethos
Sent: Sunday, June 06, 2004 4:50 PM
Subject: Re: [STOVES] [ethos] Bricks from Ken Goyer

Dear Kachan, I started making ceramics test pieces and bricks using an electric kiln such as potters use. At first, I fired very slowly to eliminate water and burn out organic matter and then raised the temperature faster. Usually I took about twelve hours to reach 1050 oC or cone 03. Now I am amazed to discover that just about anything you do to fire bricks works as long as you can get them to be red hot. Even if you go fast. I'm sorry that I don't have the time right now to post some pictures of kilns that have worked. Like I said, I am amazed, almost any contained space to which you can apply heat long enough seems to work. The economy of scale with bricks is in making thousands of them at once. Best regards, Ken Goyer

Kanchan Rai wrote:

Dear ken goyer,
thanks for providing information on clay and bricks. Could you tell me
what kind of kiln are you using for baking bricks, how long do you bake
at what temperature?

kanchan

Dear Friends, If the brick is particularly weak or won't hold
together when fired it is probably the fault of the clay. All clays
are not equal. Brick makers should know their clay body and how to
adjust it. If you don't have the luxury of someone else's experience
then making experiments is the best way to find out. Good clay has
certain well known properties which vary depending on the use that you
have in mind. Fortunately, our ceramics are very forgiving of much of
the criteria that potters expect.. We don't care what color it becomes
when fired or how thin you can turn it on a wheel. If you can make a
ball of wet clay in your hand and it sticks together, that is a good
sign. If you can drop the ball to the ground and it flattens but
doesn't splatter, that is a good sign. Many other tests can be
performed to determine it's shrinkage and firing point etc. These
tests are described in most beginning pottery books.
Clay can be improved by processing if necessary. One method would
be
to stir up a pond of clay with a beast (an animal like a horse or
oxen). The mud that goes into suspension is decanted off to another
pond where it is allowed to settle. This way sand and other impurities
are removes and the smaller clay particles are hi-graded. Potters
sometimes use a barrel with a motor driven propeller to stir up a
slurry of clay allowing heavies to settle and then drain off the fine
particles into another barrel. But this will not produce enough clay
for a high production operation. The best solution is to find a good
clean clay body sufficient for your needs for a long time.
I don't understand why your bricks won't dry, unless it's raining
all of the time or the humidity is extremely high. I have never had
drying problems when using sawdust. I have had drying problems when
using paper, newspaper, cardboard, flour, and some types of ground up
vegetables. I like to use cement in a brick. The brick will harden in
a day and then it can be handled and turned so more sides are exposed
to the air. Also the brick will shrink less. I have made many
successful bricks with no cement as well. It might take a brick a week
to dry completely. Here in Oregon in the rainy season (most of the
time) I like to dry bricks indoors. Often times, due to lack of
patience, we are trying to fire wet bricks. If you proceed very slowly
this seems to work. The brick is force dried and then the temperature
is raised to burn out the organic matter and so on.
The important thing is that you keep on experimenting and
eventually
the solution will appear. Keep asking questions too! Best of luck!
Ken Goyer

From snienhuys at SNV.ORG.NP Mon Jun 7 00:37:05 2004
From: snienhuys at SNV.ORG.NP (Sjoerd Nienhuys)
Date: Tue Aug 10 18:31:14 2004
Subject: Heat from radiation v.s. conduction using shiny (real) pots
In-Reply-To: <20040607003705.88200.qmail@web41108.mail.yahoo.com>
Message-ID: <MON.7.JUN.2004.102205.0545.SNIENHUYS@SNV.ORG.NP>

Dear Stovers,

Low-income people also buy low-cost pots. These are mostly made from
different grades of aluminium. The thinner the pot, the more the pot bottom
(and sides) will be bend, dented and uneven, thus reducing heat transfer
through contact, but increase heat transfer from hot flue gasses. Also the
commonly used aluminium pressure cookers (Nepal) have slightly rounded
bottoms after some time of use, giving only a single wobbly contact point
when standing on a strong and flat top plate of the stove.
This aspect may require redesigning the solid top plate of the oven, or
educate the users on the need of flat/wide bottom pots.

When the pots are used over an open fire hole (or sunk into the hole), the
bottom will be soon black with soot; usually the sides as well when flames
are going around the pot. The amount of soot increases with poor
combustion. With improved combustion such as with the Rocket or J-stove,
the soot deposit will be less.

Cleaning the pots until they shine is an important household task of the
women. Many women are proud of a shining set of pots on the wall rack.
Cleaning aluminium pots is more work than cleaning stainless steel pots.
Often this cleaning is done with ashes; especially the ashes of some
briquettes (beehive and rice husk) have good abrasive properties.

One of the important problems of using and shining the aluminium pots
(especially on the inside) is that aluminium residues in the food are said
to cause Alzheimer's disease, becoming noticeable at advanced age. The use
of stainless steel pots and pressure cookers does not have this associated
problem, but those pots are often too expensive for the wood stove users.

A new household should start with good quality stainless steel cooking pots,
as a life-time investment. Also aluminium Teflon coated pots can be used
which do not need shining; saves time and health. Education on these
subjects may be required, and the demonstration of the best (low-cost)
cleaning method.

Firewood reduction (and getting rid of the smoke) remains a priority, taking
the large number of existing (dented) aluminium pots and pressure cookers
into consideration.

Regards,

Sjoerd Nienhuys
Senior Renewable Energy Advisor SNV-Nepal
Tel: +977-1-5523444, extension 112.
snienhuys@snv.org.np

-----Original Message-----
From: The Stoves Discussion List [mailto:STOVES@LISTSERV.REPP.ORG]On
Behalf Of David Neeley
Sent: Monday, June 07, 2004 6:22 AM
To: STOVES@LISTSERV.REPP.ORG
Subject: Re: [STOVES] Heat from radiation v.s. conduction using shiny
(real) pots

Crispin's account was fascinating. However, I have one
question. In his conclusion:

Why do you think the polished stainless would have an "even
more pronounced effect" than the aluminum pot?

However, aluminum is a superior *conductor* of heat to
stainless steel...so perhaps the difference would not be as
substantial as you may assume?

Perhaps the best solution within a fairly reasonable cost
might be a black-anodized aluminum pot--to get the best of
both worlds of radiation and convection.

Regards,

David

__________________________________
Do you Yahoo!?
Friends. Fun. Try the all-new Yahoo! Messenger.
http://messenger.yahoo.com/

From crispin at NEWDAWN.SZ Mon Jun 7 04:18:54 2004
From: crispin at NEWDAWN.SZ (Crispin Pemberton-Pigott)
Date: Tue Aug 10 18:31:14 2004
Subject: Heat from radiation v.s. conduction using shiny (real) pots
Message-ID: <MON.7.JUN.2004.101854.0200.CRISPIN@NEWDAWN.SZ>

Dear David

Trying to keep it short:

>>If I had used polished stainless steel the effect would
>>have been even more pronounced. It is possible
>>that conduction of heat to shiny pots is much more
>>important, perhaps by an order of magnitude, than it
>>has been given credit for."

>Why do you think the polished stainless would have
>an "even more pronounced effect" than the aluminum
>pot?

To be clear I was not referring to the 20 fold (Laren give an example of 18
fold) between the two pot materials, but between black v.s. shiny - just in
case anyone is not clear on that.

The reason is that the harder stainless steel takes and hold its polished
surface better than aluminum over time, and it has a high K value
(insulation value). Aluminum conducts heat about 6 times faster that
stainless steel. Stainless steel typically conducts 1/2 as much heat per
second that mild steel. A mild steel stove re-manufactured in stainless can
be considered 'insulated' to some extent as heat conduction to the surface
is 1/2 and the radiation from that surface is much lower, even if not
polished.

>I presume you assume the more reflective surface would
>absorb less radiant heat...and with that I would agree.

Yes, but I am trying to say it is the stainless steel that is shinier.

>However, aluminum is a superior *conductor* of heat
>to stainless steel...so perhaps the difference would not
>be as substantial as you may assume?

As long as we are clear I mean that the stainless steel would reject and
fail to conduct more of the heat (higher Delta T through its surface) than
the aluminum pot.

Just so people have some number to look at:

Coefficients of Heat Radiation
Cast iron, new 0.6480
Cast iron, rusted 0.6868
Copper, polished 0.0327
Iron, ordinary 0.5662
Iron, sheet polished 0.0929
Oil 1.4800
Sand 0.7400
Silver, polished 0.0266
Tin, polished 0.0439
Tinned iron, polished 0.0858
Water 1.0853
[Machinery Handbook, Industrial Press NY, ISBN 0-8311-1200]

These coefficients are in BTU's per square foot of surface per hour per
degree F increase in temperature.

Polished tin may be the closest to polished stainless steel (304). Thus
there is probably a heat radiation difference of 15.6 : 1 between a rusty
old cast iron pot and a shiny new stainless steel one.

Note too that the heat radiated by water is far higher that that of polished
metal so putting a lid on a pot is also about retaining heat, not just
keeping steam in. One square foot of pot with boiling water and no lid
loses by radiation about 300 watts worth of firewood on a continuous basis
(based on 15% PHU).

As we develop smaller and better fires in more efficient stoves, this will
become more and more significant - see previous messages about the future of
stove development - small fires, high heat transfer, preheated air etc.

Regards
Crispin

From psanders at ILSTU.EDU Mon Jun 7 12:38:39 2004
From: psanders at ILSTU.EDU (Paul S. Anderson)
Date: Tue Aug 10 18:31:14 2004
Subject: "lemon juice" battery
In-Reply-To: <006c01c44a16$12dc9b40$cb83fea9@md>
Message-ID: <MON.7.JUN.2004.113839.0500.PSANDERS@ILSTU.EDU>

Crispin,

Thanks for the info. But I remain confused.

At 11:11 AM 6/4/04 +0200, Crispin Pemberton-Pigott wrote:
>Dear Paul
>
>I must say that (nearly) all this knowledge is useless [concerning such a
>battery].

But then you say:

>I think it is very sustainable if people can get used to the idea of making
>their own power. The juice from the crushing of sisal is very corrosive and
>might be (when concentrated) highly suitable for power generation. It is a
>problem to dispose of for that reason. Rural handicrafts based on sisal
>could supply the liquid for lighting or small fans.

Yes or no?? I want a "yes", and it that means

>We are just reinventing the (electric) wheel!

then let's reinvent it but in terms that can be used by the target
societies without sufficient power to run even a VERY small fan that would
be great for some models of our stoves.

IF this most simple battery can work in an appropriate and sustainable
manner, I am sure that we will be able to find the acids and other
materials to keep it running.

Yes or No or "maybe worth the effort"? If yes or maybe, then we might
consider taking the idea beyond the Stoves List Serve to some "battery list
serve" or someplace.

Given the advances in small electrical / electronic devices and their small
power needs, even a tiny bit of sustainable electricity could have some
major benefits for people who now spend money on batteries or would use
batteries if they could afford them.

Paul

From psanders at ILSTU.EDU Mon Jun 7 18:36:55 2004
From: psanders at ILSTU.EDU (Paul S. Anderson)
Date: Tue Aug 10 18:31:14 2004
Subject: which emission is more important measuring
In-Reply-To: <6.0.1.1.2.20040605173811.01f1e8e0@express.cites.uiuc.edu>
Message-ID: <MON.7.JUN.2004.173655.0500.PSANDERS@ILSTU.EDU>

At 05:59 PM 6/5/04 -0500, Tami Bond wrote:

>Das and I have a disagreement on this-- he thinks smoke shade is okay, I
>don't. I don't like smoke shade because some of the particles from wood
>combustion aren't black, so there's not a great relationship between total
>mass and color.

What about doing the test twice, once on white filter, and once on black?

From psanders at ILSTU.EDU Mon Jun 7 18:43:08 2004
From: psanders at ILSTU.EDU (Paul S. Anderson)
Date: Tue Aug 10 18:31:14 2004
Subject: Manually powered forced air Was Re: [STOVES] Jmla Stove
In-Reply-To: <KGEALNHAOCPCAHEOEGHHCEINCGAA.snienhuys@snv.org.np>
Message-ID: <MON.7.JUN.2004.174308.0500.PSANDERS@ILSTU.EDU>

At 10:15 AM 6/4/04 +0545, Sjoerd Nienhuys wrote:
>Mountain stovers,
>
>Picture of fan is to be seen on www.icimod.org/snv the document: Mission
>report High Altitude Biogas Reactor, photo page 9.
>It is an aluminium or sheet steel hair blower type fan with a small gear to
>enhance the speed of the centrifuge.

Hi,

When I saw the picture I said: This is exactly what I purchased in January
in India. Identical, even the black cone at the exit of the air. I was
afraid that this device was too expensive for the users, and that it was
intended for forges. But you have shown otherwise. Thanks.

About the "wind fan", I looked and realized I had seen your exceptionally
good publication(s) before. I would call it a "wind vane" or "wind
suction chimney cap" (the word "fan" seems misleading). Glad to know it
works well.

David W. in highland Bolivia: Would the wind vane help there??

Paul

>The picture demonstrates the use, often only a minute or so, to get the fire
>going again. Mainly when new wood is added to the fire. At the high
>altitudes the wood usually goes into a simmer when not regularly fanned.
>
>The wind fan on the chimney is depicted in the background report of Pakistan
>stoves (same website and on stove website). It costs less than one USD,
>locally made and VERY effective.
>
>Regards,
>
>Sjoerd Nienhuys
>Senior Renewable Energy Advisor SNV-Nepal
>Tel: 5523444, extension 112.
>snienhuys@snv.org.np
>
>
>
>At 10:32 AM 6/2/04 +0545, Sjoerd Nienhuys wrote:
> >Mountain Stovers,
>snip
> > Solar PV is primarily used/wanted for illumination and TV, not at
> >all for stove fans. There is a cheap hand-operated fan available from
> >China, used by almost every household. If they are very poor, they blow in
> >a pipe.
> >With the wind picking up every afternoon, controllable chimneys can be
> >installed, costing no electricity (see former message).
>
>Sjoerd and Stovers,
>
>Please give us more information about the hand-operated fan from China, and
>how they are used (important because the TYPE of stove influences the
>usefulness of the forced air).
>
>And when blowing on a pipe, I assume you mean that is a more comfortable
>and directed way to blow on a fire instead of bending down and blowing into
>the tinder when lighting. Typically, how long would they be blowing?
>
>And how long would they typically be using the fan to assist the stove?
>
>There are many interesting issues concerning use of the relatively
>predictable and consistent wind to enhance the draft in a chimney. From
>your experience, what can you tell us about successes (and failures) with
>trying to get appropriate draft via the wind?
>
>Anyone else had these experiences? Maybe David Whitfield in the highlands
>of Bolivia? (David, that was a request for a comment from you.)
>
>Paul
>Paul S. Anderson, Ph.D.
>Dept of Geography - Geology (Box 4400), Illinois State University
>Normal, IL 61790-4400 Voice: 309-438-7360; FAX: 309-438-5310
>E-mail: psanders@ilstu.edu - Internet items: www.ilstu.edu/~psanders
>NOTE: Retired from teaching. Active in Stoves development.
>For fastest contact, please call home phone: 309-452-7072

From crispin at NEWDAWN.SZ Tue Jun 8 03:28:56 2004
From: crispin at NEWDAWN.SZ (Crispin)
Date: Tue Aug 10 18:31:14 2004
Subject: Lemon Light...by night
Message-ID: <TUE.8.JUN.2004.092856.0200.CRISPIN@NEWDAWN.SZ>

Dear Paul

The Lemon Light Ice Cube Tray Battery

I attempted to wrest a set of red and green LED's from a Toshiba
Satellite Pro (which I might add is a laptop you should not ever try to
open with anything less than a hammer) and a couple of cuts and bruises
later I had the power control panel in my hand and a large number of
broken parts scattered on the floor. The board has several LED's on it.

I tested them by hooking a single 1.6 volt dry cell battery (a new one)
in series with a brake light bulb (12 ohms). If I had a soldering iron
at home it would have been easier. Nothing at all happened.

I tried two dry cells in series and the LED's worked very well (one or
two at a time) and did not burn out. It absolutely would not work with
one battery so clearly the forward breakdown voltage is between 1.6 and
3.2 volts. Perhaps it is 2 volts at a minimum. By this time I really
wished I had a soldering iron.

The LED's worked well and did not blow. They were pretty bright. If
the forward breakdown voltage is 2 volts, then the current flowing is
1.2v/12 ohms = 100 ma which seems a bit high. If the breakdown voltage
is 2.5v the current flowing is 0.7v/12 ohms = 58ma which is believable.

Next, I found some tinned copper wire (silver in colour but copper
inside). Knowing this is not as good as a galvanized wire I proceeded
because that is all I could find in the junk box. I made 6 small
rectangles with one end poking up and sat each on in the 'cell' of a
plastic icecube tray.

Next, I made a smaller rectangle out of some thick solder (lead+tin) and
sat one in each cell so that it did not touch the copper wire and
connected each pair to make a 6 cell copper/lead battery.

Next, I went into the garden and picked a large lemon from the tree in
the round flowerbed off the patio and sliced it in two. I squeezed the
juice out and added it to the cells putting in the pulp as well hoping
that it might keep things acid.

Then I connected the two output wires to a pair of multimeter leads (the
meter itself having disappeared some time ago). With these two leads I
connected the Lemon Light battery to the LED panel.

Nothing at all happened. I reversed the leads and still a complete
blank. Not enough voltage.

Next I put one of the dry cells in series with my battery to see if mine
would give it enough of a boost to start the current flowing. This was
successful and the lights would blink on as I rubbed the lead up and
down the multi-lead strip that the manufacturers used to plug the panel
into the motherboard.

I was able to hold the power wire onto two contacts at the same time and
both of the LED's lit up. The illumination was weak (low current)
however my generating area was no more than 280 sq mm per cell.

I did manage to get a photograph of the LED working by turning off the
room light and raising the brightness of the resulting JPG. I am
attaching a photo of the whole device and the picture taken in the dark
which you, Paul, will receive but which will get stripped from the
message posted to the group. In case you were wondering, the thing for
taking stones out of horses hooves on the Swiss Army knife is clamping a
thin solder wire onto the common lead and the black lead is lying on one
of the green LED's contact. The other contacts are twisted and the
battery is taped to its leads.

Conclusion:
The 6-Cell Lemon Light Battery was generating 1 volt in spite of the
very poor choice of metals. When put in series with the 1.6 volt dry
cell it was able to illuminate 2 small LED's which probably require 2.5
volts to fire.

I have built Lemon batteries in Abidjan using only wires (copper and
galvanized steel) plugged into lemons and used them to run a 1.5 volt
clock. The typical clock requires 2 banks of 6 lemons in series.

I will leave my Lemon Light runing to see what happens in the next few
days.

It occurred to me today that one of the best ways to make such a cell in
a remote location with enough power to run a small fan or LED's is to
take an old car battery apart with a hacksaw and make two double cell
batteries, or more appropriately, separate and use only two of the
plates and make many batteries of two plates each! Of course it will
help to have a citrus tree nearby...

Illuminatingly yours,
Crispin

From crispin at NEWDAWN.SZ Tue Jun 8 03:59:06 2004
From: crispin at NEWDAWN.SZ (Crispin)
Date: Tue Aug 10 18:31:14 2004
Subject: Absortion chillers using our heat
Message-ID: <TUE.8.JUN.2004.095906.0200.CRISPIN@NEWDAWN.SZ>

Dear Stove-powered refrigerators

Around here you are not allowed to use commercially or sell a heat-powered
device (or air compressor) that operates at a pressure above 4 Bars
(atmospheres) unless it is inspected (inside) annually by a certified
inspector of pressure vessels.

As the ammonia fridge runs at pressures up to 240 psi (intimidating enough
as that is for the experienced craftsman) I doubt that it is a low cost
option for rural areas, even though the technology seems most suitable in
principle.

Regards
Crispin

From TOMBREED at COMCAST.NET Tue Jun 8 14:09:08 2004
From: TOMBREED at COMCAST.NET (TOMBREED@COMCAST.NET)
Date: Tue Aug 10 18:31:14 2004
Subject: Heat from radiation v.s. conduction using shiny (real) pots
Message-ID: <TUE.8.JUN.2004.180908.0000.>

Dear Crispin, ADK and All:

Excellent pragmatic experiment on radiation/convection components in cooking.

You mentioned that the black pot is more easily heated by radiation, but also re-radiates the heat better. We need a Greenhouse Effect for Cooking to change this.

Visible light peaks at 0.5 microns (micrometers); 1000K radiation peaks at ~ 3 microns; 400 K (pot temperature) peaks about 10 microns.

So we need soot that is highly absorbtive at 3 microns, but does not re-radiate at 10 microns. This may or not be possible.

~~~~~~
The physics of the black body radiation curve lays the foundation for quantum mechanics and is based at long wavelength on radiation from classical oscillators but at short wavelength on quantum limited radiation.

"Soot" is formed from single atoms aglomerating together in the gas phase, while charcoal is formed in the solid phase. Soot has a diameter typically less than 0.1 microns.

I have long speculated that the soot in a candle flame does NOT follow the black body radiation curve because the particles are too small to radiate well below their own size (0.1 micron). As far as I know no one has attempted to measure the radiation from a candle or from soot at very long wavelengths.

So, maybe soot has the right properties to absorb the short wavelength IR from the hot charcoal, but no reradiate it at the longer wavelength of the pot temperature.

Comments?

Yours truly, TOM REED BEF STOVEWORKS

> Bravo Crispin! A fantastic set of experiments. Now we have to discourage
> housewives from scrubbing the pots to a shine :-). I always thought that
> placing a pot on the Plancha stove would be less efficient than placing the
> pot directly on the fire. But your experiments indicate that the hot plate
> of the Plancha was just what the doctor ordered, at least in the case of
> shiny new pots. Your experiments give a new direction to stove designing.
> Yours
> A.D.Karve
> ----- Original Message -----
> From: Crispin Pemberton-Pigott <crispin@newdawn.sz>
> To: <STOVES@LISTSERV.REPP.ORG>
> Sent: Saturday, June 05, 2004 12:10 AM
> Subject: [STOVES] Heat from radiation v.s. conduction using shiny (real)
> pots
>
>
> > Dear Stovers
> >
> > I have been checking out the difference in heat received from radiation
> and
> > conduction when cooking with ordinary shiny aluminum pots, seeing as that
> is
> > what people use.
> >
> > I have hear various figures bandied about with regard to how many times
> more
> > heat is yielded to the pot when it is radiated instead of conducted either
> > from touching a metal surface or from touching hot gases. My thumb-suck
> > experiments were somewhat surprising.
> >
> > First, I went to a pot spinning shop and had them make me a lipped
> > handle-less pot 152 deep and 220 in diameter. This I sunk into a small
> > downdraft coal stove so that the whole area of the pot was exposed to hot
> > gases with passage gaps of about 10mm.
> >
> > In a regular stove like a Rocket 2-pot with a fire under the first pot
> (Pot
> > 1) the gases then pass around Pot 2 to pick up heat otherwise wasted.
> There
> > was a good picture posted some time ago of a stainless steel 2-pot Rocket
> > stove with integrated oven. It was at the ETHOS meeting. I have used
> that
> > particular unit so I had some idea of what it was like and what my stoves
> > are like with a similar heat-collection pot.
> >
> > My plan was to see what happens if the pot is highly polished. It will
> tend
> > not to pick up radiated heat and then it will tend to keep heat in once it
> > gets hold of it because its radiation coefficient is so poor.
> >
> > Second, I put 5 litres of water into the pot in position 2 (collecting
> waste
> > heat). This took 33 minutes to come to a vigorous boil. By the time it
> did
> > the mirror finish was covered with a light dusting of white ash which
> wasn't
> > all that surprising. I suppose it insulated it a tiny bit. The part of
> the
> > pot which was not exposed to the front or side of the gas stream remained
> > clean and shiny. I suspect that nearly none of the heat that was in the
> pot
> > radiated away towards the chimney from that 'back' surface. In other
> words,
> > it was partially self-insulating by being reflective.
> >
> > Third, I balanced a large (240mm) diameter pot over the fire so that the
> > bottom was about 50mm away from the red coals. This was a sanded aluminum
> > finish on the bottom with highly polished sides. The idea was to pick up
> > heat and boil a small amount of water. It was about 2 litres and boiled
> in
> > about 11 minutes.
> >
> > Fourth, I got tired of holding the pot and rested it on two 12mm steel
> bars
> > spanning the fire. This resulted in a higher boiling rate which
> interested
> > me as the huge amount of radiated heat was, according what I have heard
> > about the effectiveness of radiation, supposed to *way* outweigh the
> effect
> > of conducted heat from sitting on the thin bar contact area.
> >
> > Looking in I could see that the boiling was coming not from the bottom
> where
> > all the radiation hit the pot but from 2 clearly defined lines of bubbles
> > corresponding to where it sat on the rods. The water bubbled like crazy
> > along those two lines and hardly at all from the rest of the bottom, even
> > though it was 50mm from at least 4 to 5 KW of radiant heat. The silvery
> > bottom is an effective reflector.
> >
> > Fifth, I placed over the coals an old battered aluminum pot with a burned
> > black bottom (230 mm diameter, 4 litre). It heated far faster than the
> new
> > pot did, but it still liked the contact with the rods.
> >
> > Sixth, I placed a black 3mm thick mild steel plate over the fire
> (completely
> > removing radiation) and put the large pot on top of it. Surprisingly, in
> > spite of the shrinking fire it brought 6+ litres of water to a low boil.
> I
> > expected that would not be possible because of the low power input through
> > the plate, however the ability of the pot to retain heat insides its
> > polished walls was amazing.
> >
> > Conclusion: I think this radiated heat business needs a good looking into.
> > On the face of it, conduction was a far stronger deliverer of heat to a
> > clean aluminum pot than radiation was. If I had used polished stainless
> > steel the effect would have been even more pronounced. It is possible
> that
> > conduction of heat to shiny pots is much more important, perhaps by an
> order
> > of magnitude, than it has been given credit for. As distance from the
> fire
> > to the pot is often a 'defining criterion' of stove manuals, it is likely
> > that significant changes are needed in the approach to heat transfer
> theory
> > given in DIY manuals.
> >
> > This has a lot of interesting implications for people cooking with
> paraffin
> > (clean burning ones) and charcoal. People like charcoal because it
> doesn't
> > dirty the pots, but I'll bet they don't know that they should use a black
> > plate in between a shiny pot and the fire to save fuel. Perhaps it should
> > be perforated. Who knows? Has anyone been looking?
> >
> > I think this is something everyone should try at home to see what they
> find.
> > Use a shiny stainless steel pot and put it on a flat black plate over a
> gas
> > fire, charcoal fire, wood fire and an electric hot plate. I will bet that
> > the heat transfer and heat retention when using an electric stove without
> a
> > plate in between is excellent, and that when using a charcoal fire it
> > improves with some form of a plate.
> >
> > I wouldn't be all that surprised to see an increase in heat transfer
> > efficiency over a gas flame with a plate in between. It probably depends
> a
> > lot on the flame gas velocity towards/at the pot.
> >
> > This all goes to show that the pot is an intergal part of the cooking
> > experience and a variable of underrated significance in the evaluation of
> a
> > stoves performance.
> >
> > Sincerely
> > Crispin

From TOMBREED at COMCAST.NET Tue Jun 8 14:19:13 2004
From: TOMBREED at COMCAST.NET (TOMBREED@COMCAST.NET)
Date: Tue Aug 10 18:31:14 2004
Subject: which emission is more important measuring
Message-ID: <TUE.8.JUN.2004.181913.0000.>

Dear Paul and All:

Paul has a good suggestion here. I think Das and Tami should devise an experiment to test the Das hypothesis.

Here's a puzzle whose solution may be part of the answer.

The dominant components of high temperature tars are typically primarily poly nuclear aromatics such as naphthalene, anthracene etc., all WHITE in the visible spectrum. (Benz a pyrene maybe yellow). Yet the filter spots are all black.

If you extreact the tars with benzene, they will glow colored in UV light. I have tried using paper chromatography to "develop" the tars away from the soot spot but didn't seem to have the right conditions for paper chromatographic separation.

I presume this is because the conditions for making tars are close to the conditions for making soot, so to the extent they occur together measurement of blackness also is a measure of tar. The tars in downdraft gasifiers are all PNAs; those formed at lower temperatures have other structures.

It would be good for both the gasification and stove group to get more scientific about tars.

Comments?

Yours truly, TOM REED BEF STOVEWORKS IN LONG BEACH

> At 05:59 PM 6/5/04 -0500, Tami Bond wrote:
>
> >Das and I have a disagreement on this-- he thinks smoke shade is okay, I
> >don't. I don't like smoke shade because some of the particles from wood
> >combustion aren't black, so there's not a great relationship between total
> >mass and color.
>
> What about doing the test twice, once on white filter, and once on black?
>
> Paul
> Paul S. Anderson, Ph.D.
> Dept of Geography - Geology (Box 4400), Illinois State University
> Normal, IL 61790-4400 Voice: 309-438-7360; FAX: 309-438-5310
> E-mail: psanders@ilstu.edu - Internet items: www.ilstu.edu/~psanders
> NOTE: Retired from teaching. Active in Stoves development.
> For fastest contact, please call home phone: 309-452-7072

From ajh at SYLVA.ICUKLIVE.CO.UK Tue Jun 8 17:27:49 2004
From: ajh at SYLVA.ICUKLIVE.CO.UK (AJH)
Date: Tue Aug 10 18:31:14 2004
Subject: Lights--especially CFL
In-Reply-To: <8n47c0tdrjih3td24qtrev07b9r5tcd33k@4ax.com>
Message-ID: <TUE.8.JUN.2004.222749.0100.AJH@SYLVA.ICUKLIVE.CO.UK>

On Sun, 6 Jun 2004 23:13:44 +0100, Andrew Heggie wrote:

>
>This is my take, the high frequency CFL is the most electricity
>efficient at domestic lighting levels.
>>
>>In my opinion, LED lights are best where portability or
>>very long life are more important than individual cost.
>
>Which just goes to illustrate that there is more in the total life
>cost than energy efficiency alone.

I have had a quick web search to illustrate a point and it seems to me
that the smallest CFLs are 3W devices, now ken Goyer's project looks
at using 3 LEDs consuming ~100mA with a redundant cellphone battery. I
am guessing this gives just sufficient light for the purpose with
~250mW, so the luxury of the extra lumens from the CFL become un
affordable in terms of power consumption.

Has anybody else tried metal-metal seebeck effect generators, Ken
managed 0.02V from 9 junctions of copper-iron, would adding extra
junctions be counter productive in that the additional voltage would
be countered by increased series resistance. I posted on this back in
February where it looked like a series of nickel-iron junctions would
be better.

AJH

From list at SYLVA.ICUKLIVE.CO.UK Tue Jun 8 17:27:49 2004
From: list at SYLVA.ICUKLIVE.CO.UK (Andrew Heggie)
Date: Tue Aug 10 18:31:14 2004
Subject: use of outside air with analysis KR
In-Reply-To: <7us6c0t01dbnjscbub1k5k98pvdci3sgls@4ax.com>
Message-ID: <TUE.8.JUN.2004.222749.0100.>

On Sun, 6 Jun 2004 22:22:36 +0100, Andrew Heggie wrote:

>We may be talking at cross purposes here, I was meaning air changes
>for the comfort and health of the occupants, which I felt was best
>incorporated into the combustion air, I've come back to nearly 100
>messages on Stoves (well done all) so I will take a while to catch up,
>I shall see what the recommended air changes are for a kitchen in UK.

I have been directed to
http://www.vent-axia.com/sharing/requirements.asp

the minimum range seems to be 1-2 air changes per hour up to over 10
with crowded smoky atmospheres.

Which gives some suggestions for necessary air changes, so given
Rajendra's rate of biomass burning and knowledge of the size of room
and occupancy we should be able to calculate the practicality of
having a balanced room sealed, vented system.

It also occurs to me that Laren may be able to comment on the
possibility of both conserving heat and making use of passive solar
techniques using the vernacular building materials we can see in
Sjoerd's pictures. I imagine just as in my society conservation will
give more bangs per buck.

AJH

From mheat at MHA-NET.ORG Tue Jun 8 18:07:26 2004
From: mheat at MHA-NET.ORG (Norbert Senf)
Date: Tue Aug 10 18:31:14 2004
Subject: which emission is more important measuring
In-Reply-To: <060820041819.22283.40C6032100020EB20000570B2200750744BBBAB
AADBDB3B1AB@comcast.net>
Message-ID: <TUE.8.JUN.2004.180726.0400.MHEAT@MHANET.ORG>

At 06:19 PM 2004-06-08 +0000, TOMBREED@COMCAST.NET wrote:
>(snip)
>I presume this is because the conditions for making tars are close to the
>conditions for making soot, so to the extent they occur together
>measurement of blackness also is a measure of tar. The tars in downdraft
>gasifiers are all PNAs; those formed at lower temperatures have other
>structures.

Hello Stovers:

A few years back, we did some PM measurements on masonry heaters and
fireplaces. We used a small "Condar" dilution tunnel which extracted a part
of the exhaust at a fixed flow rate and mixed it with 10 parts air before
running it through filters. We then weighed the filters. It is roughly
compatible with US-EPA method 5.

We got some useful qualitative info by examining the filters afterwards and
smelling them. There seemed to be three categories:

- no smell -- black filter, light weight, all soot
- "campfire smell" - black filter, medium weight, mix of soot and tar
- "creosote" or strong chemical smell - yellowish brown filter, heavy weight

So, bad combustion with high PM emissions also seemed to correlate with
more tarry, PAH type emissions.
Good combustion resulted in a bit of soot during the cold start phase, low
PM, and sometimes black filters.

These observations may be valid for this type of appliance only, where we
burn a 60 lb batch of cordwood from a cold start and at a high burn rate.
Also, there was a strong correlation between the measured particulate
emissions and the amount and type (black or blue) smoke visible from the
stack. Low emissions correlated with the absence of visible smoke (other
than condensed steam). For a 2 hour burn, roughly half the PM happened
during the 15 minute cold start.

Best ...... Norbert

----------------------------------------
Norbert Senf---------- mheat@mha-net.org-nospam
Masonry Stove Builders (remove -nospam)
RR 5, Shawville------- www.heatkit.com
Quebec J0X 2Y0-------- fax:-----819.647.6082
---------------------- voice:---819.647.5092

From kenboak at STIRLINGSERVICE.FREESERVE.CO.UK Tue Jun 8 20:05:42 2004
From: kenboak at STIRLINGSERVICE.FREESERVE.CO.UK (Ken Boak)
Date: Tue Aug 10 18:31:14 2004
Subject: Simple charcoal stove designs?
Message-ID: <WED.9.JUN.2004.010542.0100.KENBOAK@STIRLINGSERVICE.FREESERVE.CO.UK>

Stovers,

Today the temperature in London reached 29 C in the shade at noon, which
encouraged me to try some simple charcoal stove ideas tonight using my cheap
Chinese pot-bellied barbeque - a cast iron pot about 20cm (8") in diameter,
a 20cm grate and with a wok-like top and a cast-iron grid.

I have a supply of excellent English lumpwood charcoal, thanks to fellow
Stover David Reynolds Lacey.

I tried some boiling tests using an 18cm stainless steel pan, with a 1cm
steel plate on the bottom and a glass lid.

My first test was 1 lite of water and 250g of potatoes and 3g of salt. In
the unmodified barbeque with an 20cm (8") diameter of burning charcoal
the pot boiled in 15 minutes exactly.

After eating, I tried to make a more compact 15 cm (6") charcoal burner from
an old coffee tin. Sadly the boil time for 1250 ml of water increased to 22
minutes.

I tried a 15cm diameter sleeve made from perforated steel sheet to contain
the charcoal in a makeshift brazier and this seemed to work OK as long as
the fuel level was kept up close to the bottom of the pan.

Should I be looking towards riser sleeves for this type of stove - if so
what diameter.

Can I burn charcoal efficiently without forced draught?

Here are some facts and figures:

Fuel type: English lumpwood charcoal
Fuel Charge: 325g
Cold water starting temp: 15.5 C
Pot diameter: 18 cm
Pot height 8.5 cm. and 1cm thick steel bottom.
Volume of water 1250ml
Best boil time: 15:00 minutes
Altitude 30m above sea level
Ambient temp 22 C

If anyone can advise me how to make a tincan stove for better burn
efficiency of charcoal I would love to hear some practical advice.

regards,

Ken

(London)

From kenboak at STIRLINGSERVICE.FREESERVE.CO.UK Wed Jun 9 05:43:57 2004
From: kenboak at STIRLINGSERVICE.FREESERVE.CO.UK (Ken Boak)
Date: Tue Aug 10 18:31:14 2004
Subject: Simple Charcoal Stove designs
Message-ID: <WED.9.JUN.2004.104357.0100.KENBOAK@STIRLINGSERVICE.FREESERVE.CO.UK>

Dear Stovers,

Following yesterday's post, I have had a few further thoughts about the basic problems of efficient burning of charcoal in a small stove. I also have learnt the significance of the roles of the primary and secondary air supply.

My tests are based on a standard stainless steel 18cm pot containing 1.25l of water - with a starting temperature of 15.5 C.

The fuel is English lumpwood charcoal, and I found that 325g can be loosely packed into a 500gram coffee tin.

With the calorific value of charcoal being about 33kJ/g - I ought to get much more heat from my 325g charge - almost 3kWh.

These coffee tins are a nominal 15cm (6") diameter by 12.7 cm (5") tall and make a convenient size for experiments on this scale. They are also readily available - as I have been collecting them for some time.

I would like to try and keep the burning area to that which can be contained within a 15cm diameter - or smaller.

My overall aim is to minimise the charcoal consumption and minimise the boil time for the pan of water.

Barbeques work well by generally spreading the charcoal over a large surface area, perhaps to a depth of only 1 or 2 lumps. This maximises the amount of oxygen that can reach the burning pieces. This is ideal for grilling - but not so good for concentrating the heat into the base of a pot.

As such, confining the charcoal within a can, where there is really only good mixing of the primary air source at the base of the column around the grate area, means that the charcoal closest to the grate consumes all the oxygen and starves the upper strata of primary air. So the upper strata must receive sufficient secondary air in order to burn and contribute heat.

Where the charcoal does burn in the lower section of the can, it creates a lot of heat and this is generally radiated from the metal walls of the can. I discovered this whilst burning charcoal in the main "pot" of my barbeque - much of the heat went straight into the cast iron wall, with little actually contributing to boiling the water in the pan above.

I tried to reduce the heat loss into the walls of the barbeque by burning the charcoal in an inner can (150mm dia coffee tin - with both ends removed). Although reducing the heat loss - this caused further problems by lack of primary air.

I tried to eliminate this air starvation by making up a second "can" made from perforated steel sheet (2.3mm holes on a 4.75mm pitch - like the screen material from an old meat-safe). This I hoped would encourage more primary air to mix with the charcoal in the upper strata. I hope to be able to prove this later today. This should also act as an air pre-heater, so that air rising between the inner and outer would be heated and reach the secondary combustion zone already quite hot.

So a column of charcoal will really only generate heat at the top and at the bottom, where the air is available. The bit in the middle, although receiving a lot of heat from the combustion of the lower bed is likely to be starved of oxygen - but hopefully will be undergoing reduction into CO and H2. Getting the balance between primary and secondary air correct is difficult, and I am sure that the ratio of diameter of the charcoal column to its height has a great significance on the performance of this type of stove.

If anyone has experience of burning charcoal within the confines of a 150mm (6") can - I would be interested to know. Any web links to simple charcoal stoves also appreciated

If the conventional method of a primary air source at the base is not satisfactory, I may try introducing some forced draught both at the primary and secondary zones.

I had a certain amount of success with my simple "Aardvark" burner (built 2002) where air was introduced through a nozzle at the top of the can - and created a cyclone of turbulent airflow across the top of the fuel bed.

There is a small picture of the "Aardvark" on this web page - www.geocities.com/wastewatts/index.html

regards,

Ken

From list at SYLVA.ICUKLIVE.CO.UK Wed Jun 9 06:38:22 2004
From: list at SYLVA.ICUKLIVE.CO.UK (Andrew Heggie)
Date: Tue Aug 10 18:31:14 2004
Subject: which emission is more important measuring
In-Reply-To: <4.3.1.2.20040607173509.02522160@mail.ilstu.edu>
Message-ID: <WED.9.JUN.2004.113822.0100.>

On Mon, 7 Jun 2004 17:36:55 -0500, Paul S. Anderson wrote:

The opacity of a black filter would be at the end of the scale anyway,
so any more darkening from any source would make no difference.

I think the point that Tami was making is that the simple soot spot
test, whereby you suck a known volume of gas through the filter and
then compare the spot against a calibrated (in shades of grey) chart
to estimate the particulates in the flue gas, is only comparable if
the particulates involved are the same colour. Further she says that
particulates from wood burning are often less black than from other
fuels. So that by doing this test with a woodburning device the result
may well under estimate the particulate load because the spot will not
be as dark.

Basically it underestimates the PAH fraction of the flue gas
particulates and probably fly ash also.

Her links suggest a more correct way to estimate it is to suck a cool
sample through a filter and then weight the change in weight of the
filter. This is very difficult to do in the field. She also refers to
methods using light back scatter techniques, again requiring
sophisticated equipment.

AJH

From crispin at NEWDAWN.SZ Wed Jun 9 07:08:09 2004
From: crispin at NEWDAWN.SZ (Crispin Pemberton-Pigott)
Date: Tue Aug 10 18:31:14 2004
Subject: Simple charcoal stove designs?
Message-ID: <WED.9.JUN.2004.130809.0200.CRISPIN@NEWDAWN.SZ>

Dear Ken

I read that your pot is a stainless steel 18cm unit with a "1 cm thick
bottom".

This is possible but unlikely to be a stainless steel bottom even if it
looks like it is.

If you see a joint between the bottom covering of the pot and the bottom
corner of the side wall of the pot, there is probably an aluminum filled
cavity across the bottom to spread heat rapidly and evenly.

The pot is made by pressing a flat sheet into a pot shape. The bottom is a
thin stamping. The filler is an aluminum plate which is spun welded between
the two stainless parts until it melts and then the two parts are pressed
together while the aluminum cools and glues them together. You can
sometimes separate the two parts by heating the pot with nothing in it.

Regards
Crispin

From hseaver at CYBERSHAMANIX.COM Wed Jun 9 07:43:33 2004
From: hseaver at CYBERSHAMANIX.COM (Harmon Seaver)
Date: Tue Aug 10 18:31:14 2004
Subject: use of outside air with analysis KR
In-Reply-To: <7us6c0t01dbnjscbub1k5k98pvdci3sgls@4ax.com>
Message-ID: <WED.9.JUN.2004.064333.0500.HSEAVER@CYBERSHAMANIX.COM>

On Sun, Jun 06, 2004 at 10:22:36PM +0100, Andrew Heggie wrote:
> On Mon, 31 May 2004 00:18:57 +0545, Kanchan Rai wrote:
>
> >For the passage of air on the ground might be insulated using locally
> >available material. A tree called silver porch is available in that
> >area, which has a paper like layers which is very good insulator. People
> >use such thing to insulate their roof.
>
> Kanchan, this sounds like silver birch, the betula family,
> characterised by an oily bark which finds many uses (canoes in the US)
> >

Silver birch is Betula pendula and isn't used for its bark, AFAIK. And
a much smaller tree than the White Birch (also called Paper Birch), Betula
papyrifera, which is native all around the globe, at least in the north. Paper
Birch is the tree bark used for water proofing roofs, also to make canoes,
baskets, etc. Also excellent fire-starter. The bark can be harvested for canoes,
roofing, etc. without harming the tree, if done properly. Once widely used in
Sweden and Norway for a waterproofing layer beneath the sod roofs, perhaps
elsewhere.

--
Harmon Seaver
CyberShamanix
http://www.cybershamanix.com
Hoka hey!

From jeff.forssell at CFL.SE Wed Jun 9 08:29:48 2004
From: jeff.forssell at CFL.SE (Jeff Forssell)
Date: Tue Aug 10 18:31:14 2004
Subject: Birch bark (and Root "Beer"!)
Message-ID: <WED.9.JUN.2004.142948.0200.JEFF.FORSSELL@CFL.SE>

Birch bark called "n?ver" in swedish:

Classic Campfire starter

Pictures of use as roof waterproofing
http://www.lappland.ac/www.unc.se/foretag/bild/torvsjo/to7.jpg
http://www.byggtradition.se/stuga_tak.jpg

Harvesting:
http://www.new-renaissance.eenet.ee/hemslojden/pix-pages-svenska/5-material.htm

It has been traditionally used for making useful things: shoes, containers

Some examples of modern "hobby craft" using the same techniques.
www.finurliga-myran.com/naver.htm

> -----Original Message-----
> From: The Stoves Discussion List
> [mailto:STOVES@LISTSERV.REPP.ORG] On Behalf Of Harmon Seaver
> Sent: Wednesday, June 09, 2004 1:44 PM
> To: STOVES@LISTSERV.REPP.ORG
> Subject: Re: [STOVES] use of outside air with analysis KR
>
> On Sun, Jun 06, 2004 at 10:22:36PM +0100, Andrew Heggie wrote:
> > On Mon, 31 May 2004 00:18:57 +0545, Kanchan Rai wrote:
> >
> > >For the passage of air on the ground might be insulated
> using locally
> > >available material. A tree called silver porch is
> available in that
> > >area, which has a paper like layers which is very good insulator.
> > >People use such thing to insulate their roof.
> >
> > Kanchan, this sounds like silver birch, the betula family,
> > characterised by an oily bark which finds many uses (canoes
> in the US)
> > >
>
> Silver birch is Betula pendula and isn't used for its
> bark, AFAIK. And a much smaller tree than the White Birch
> (also called Paper Birch), Betula papyrifera, which is native
> all around the globe, at least in the north. Paper Birch is
> the tree bark used for water proofing roofs, also to make
> canoes, baskets, etc. Also excellent fire-starter. The bark

Birch bark called "n?ver" in Swedish has had thousands of uses:

Classic Campfire starter

Pictures of use as roof waterproofing
http://www.lappland.ac/www.unc.se/foretag/bild/torvsjo/to7.jpg
http://www.byggtradition.se/stuga_tak.jpg

Harvesting:
http://www.new-renaissance.eenet.ee/hemslojden/pix-pages-svenska/5-material.htm

It has been traditionally used for making useful things: shoes, containers

Some examples of modern "hobby craft" using the same techniques.
www.finurliga-myran.com/naver.htm

I discovered when making root handicraft of birch roots that the reddish root bark we scraped off had the aroma of Root Beer (a classic US soft drink that [unfortunately for me] has not invaded Sweden {like Coke & Pepsi}). I cooked a "tea" with it and mixed with sugar and yeast. And bottled up after a couple days. Perfect!

Jeff Forssell
SWEDISH AGENCY FOR FLEXIBLE LEARNING (CFL)
Box 3024
SE-871 03 H?RN?SAND /Sweden
http://www.cfl.se/?sid=60
+46(0)611-55 79 48 (Work) +46(0)611-55 79 80 (Fax Work)
+46(0)611-22 1 44 (Home) ( mobil: 070- 35 80 306; [070-4091514])

From dstill at EPUD.NET Wed Jun 9 12:48:53 2004
From: dstill at EPUD.NET (Dean Still)
Date: Tue Aug 10 18:31:14 2004
Subject: plancha vs open fire
Message-ID: <WED.9.JUN.2004.094853.0700.DSTILL@EPUD.NET>

Dear Friends,

> A.D. Karve said," I always
> thought that placing a pot on the Plancha stove would be less
> efficient than placing the pot directly on the fire."

We have done a lot of experiments here and in Central America with plancha
stoves. A cold plancha or griddle can take a longer time to boil water
compared to an open fire. But, a red hot spot on the plancha in contact with
a pot can boil the water slightly faster than an open fire. The expertly
operated open fire can be a lot more fuel efficient compared to a cold start
boil on a plancha stove. Plancha stoves can be made to efficiently heat the
griddle but if only one pot is on the griddle a lot of the heat is wasted.

Plancha stoves are inherently inefficient compared to stoves that force the
hot flue gases to scrape against the bottom and sides of the pot. We use
plancha designs in Central America because folks insisted that pots stay
clean. The small fuel magazine plus cooks using multiple pots made the
plancha fuel saving compared to very badly made open fires, the practice in
many communities. But the optimized stove is twice as fuel efficient
compared to the plancha. 17% PHU vs 35% PHU. (Tami Bond scored around 30%
PHU with her award winning open fire test.)

Studies show that the plancha stove saves a lot of wood in practice but it
is a compromise and has some trade offs due to consumer preference.

All Best,

Dean

From phoenix98604 at EARTHLINK.NET Wed Jun 9 14:46:14 2004
From: phoenix98604 at EARTHLINK.NET (Art Krenzel)
Date: Tue Aug 10 18:31:14 2004
Subject: Lemon Light...by night
Message-ID: <WED.9.JUN.2004.114614.0700.PHOENIX98604@EARTHLINK.NET>

Crispin,

This thread is beginning to sound like an international Science Fair
Project. :-)

Keep up the great enthusiasm.

Art Krenzel

----- Original Message -----
From: "Crispin" <crispin@newdawn.sz>
To: <STOVES@LISTSERV.REPP.ORG>
Sent: Tuesday, June 08, 2004 12:28 AM
Subject: [STOVES] Lemon Light...by night

> Dear Paul
>
> The Lemon Light Ice Cube Tray Battery
>
> I attempted to wrest a set of red and green LED's from a Toshiba
> Satellite Pro (which I might add is a laptop you should not ever try to
> open with anything less than a hammer) and a couple of cuts and bruises
> later I had the power control panel in my hand and a large number of
> broken parts scattered on the floor. The board has several LED's on it.
>
> I tested them by hooking a single 1.6 volt dry cell battery (a new one)
> in series with a brake light bulb (12 ohms). If I had a soldering iron
> at home it would have been easier. Nothing at all happened.
>
> I tried two dry cells in series and the LED's worked very well (one or
> two at a time) and did not burn out. It absolutely would not work with
> one battery so clearly the forward breakdown voltage is between 1.6 and
> 3.2 volts. Perhaps it is 2 volts at a minimum. By this time I really
> wished I had a soldering iron.
>
> The LED's worked well and did not blow. They were pretty bright. If
> the forward breakdown voltage is 2 volts, then the current flowing is
> 1.2v/12 ohms = 100 ma which seems a bit high. If the breakdown voltage
> is 2.5v the current flowing is 0.7v/12 ohms = 58ma which is believable.
>
> Next, I found some tinned copper wire (silver in colour but copper
> inside). Knowing this is not as good as a galvanized wire I proceeded
> because that is all I could find in the junk box. I made 6 small
> rectangles with one end poking up and sat each on in the 'cell' of a
> plastic icecube tray.
>
> Next, I made a smaller rectangle out of some thick solder (lead+tin) and
> sat one in each cell so that it did not touch the copper wire and
> connected each pair to make a 6 cell copper/lead battery.
>
> Next, I went into the garden and picked a large lemon from the tree in
> the round flowerbed off the patio and sliced it in two. I squeezed the
> juice out and added it to the cells putting in the pulp as well hoping
> that it might keep things acid.
>
> Then I connected the two output wires to a pair of multimeter leads (the
> meter itself having disappeared some time ago). With these two leads I
> connected the Lemon Light battery to the LED panel.
>
> Nothing at all happened. I reversed the leads and still a complete
> blank. Not enough voltage.
>
> Next I put one of the dry cells in series with my battery to see if mine
> would give it enough of a boost to start the current flowing. This was
> successful and the lights would blink on as I rubbed the lead up and
> down the multi-lead strip that the manufacturers used to plug the panel
> into the motherboard.
>
> I was able to hold the power wire onto two contacts at the same time and
> both of the LED's lit up. The illumination was weak (low current)
> however my generating area was no more than 280 sq mm per cell.
>
> I did manage to get a photograph of the LED working by turning off the
> room light and raising the brightness of the resulting JPG. I am
> attaching a photo of the whole device and the picture taken in the dark
> which you, Paul, will receive but which will get stripped from the
> message posted to the group. In case you were wondering, the thing for
> taking stones out of horses hooves on the Swiss Army knife is clamping a
> thin solder wire onto the common lead and the black lead is lying on one
> of the green LED's contact. The other contacts are twisted and the
> battery is taped to its leads.
>
> Conclusion:
> The 6-Cell Lemon Light Battery was generating 1 volt in spite of the
> very poor choice of metals. When put in series with the 1.6 volt dry
> cell it was able to illuminate 2 small LED's which probably require 2.5
> volts to fire.
>
> I have built Lemon batteries in Abidjan using only wires (copper and
> galvanized steel) plugged into lemons and used them to run a 1.5 volt
> clock. The typical clock requires 2 banks of 6 lemons in series.
>
> I will leave my Lemon Light runing to see what happens in the next few
> days.
>
> It occurred to me today that one of the best ways to make such a cell in
> a remote location with enough power to run a small fan or LED's is to
> take an old car battery apart with a hacksaw and make two double cell
> batteries, or more appropriately, separate and use only two of the
> plates and make many batteries of two plates each! Of course it will
> help to have a citrus tree nearby...
>
> Illuminatingly yours,
> Crispin
>

From crispin at NEWDAWN.SZ Wed Jun 9 17:50:53 2004
From: crispin at NEWDAWN.SZ (Crispin Pemberton-Pigott)
Date: Tue Aug 10 18:31:15 2004
Subject: plancha vs open fire
Message-ID: <WED.9.JUN.2004.235053.0200.>

Dear Plancha users

Improving the performance of plancha-type cooking surfaces with pots on
them:

If the plancha has holes in it like a standard cast iron stove (cut out
of the plancha and then re-inserted with a rolled 10mm square bar
underneath to support it and close the gap) the heat transfer to the pot
is much better than with a 'whole sheet' top surface with pots sitting
on it.

An example of this approach built into a stove is show at:

http://www.newdawnengineering.com/website/stove/bakingstove/basintuthub.
htm

The larger of the two plates is directly over the fire (which is a
Tsotso style controllable combustion chamber). This top surface of this
plate reaches 350 degrees quite rapidly because it is not physically
connected to the main deck of the stove.

The smaller plate is over the oven and is used for simmering.

Taking this approach to a larger or longer plancha you can make holes
that are suited to accepting 3-legged (or other) pots which can hang
down into the holes, and regular pots can be placed over a hole with the
disc removed if the user doesn't mind getting some smoke on it.

One can put baffles in the 'right place' to ensure the discs heat up
more than the rest of the plancha, and it a simply lever is added, the
baffle can be dropped down to allow even heating over the whole thing
for pancake making etc.

Where one wants extra heat on the disc part of the time and normal heat
the rest, two or more thin(er) discs can be placed into the hole. They
conduct heat less efficiently from one to another than a solid disc.

Regards
Crispin

From crispin at NEWDAWN.SZ Wed Jun 9 18:08:14 2004
From: crispin at NEWDAWN.SZ (Crispin Pemberton-Pigott)
Date: Tue Aug 10 18:31:15 2004
Subject: Lemon Light...by night
Message-ID: <THU.10.JUN.2004.000814.0200.>

Dear Art

Wednesday night.

The light is still on! It just isn't very bright because the current is
so low.

Because the voltage required to keep an LED running is lower than the
voltage required to start it, I worried that the lemon light was being
'driven' by the 1 dry cell. I disconnected the wires to see of it would
re-start the LED and it did, indicating that the battery is still
generating enough power to take the voltage from 1.6 to whatever the
starting voltage is. Two point something.

When reconnnecting the wires I could distinctly hear the crackle of the
sparks on the FM radio on the fridge nearby as the LED lit up.

Regards
Crispin

++++++++++++++++

This thread is beginning to sound like an international Science Fair
Project. :-)

Keep up the great enthusiasm.

Art Krenzel

From rbadhi at HOTMAIL.COM Wed Jun 9 21:19:40 2004
From: rbadhi at HOTMAIL.COM (Rajendra B Adhikari)
Date: Tue Aug 10 18:31:15 2004
Subject: White LED and CFL Lamps
Message-ID: <WED.9.JUN.2004.211940.0400.RBADHI@HOTMAIL.COM>

On June 8, 2004 Andrew Heggie wrote:

>This is my take, the high frequency CFL is the most electricity efficient
at domestic lighting levels.
> In my opinion, LED lights are best where portability or very long life
are more important than > individual cost. Which just goes to
illustrate that there is more in the total life cost than energy >
efficiency alone. I have had a quick web search to illustrate a point and it
seems to me that the > smallest CFLs are 3W devices, now ken Goyer's
project looks at using 3 LEDs consuming >~100mA with a redundant cellphone
battery. I am guessing this gives just sufficient light the >
purpose with ~250mW, so the luxury of the extra lumens from the CFL become
unaffordable
> in terms of power consumption.
>>

First of all we should be clear that our main goal is to replace the
existing kerosene lamps or the pine rosin lamps used by the poor people in
the developing world, and not in Europe or in America. In other words our
benchmark is the light given by the kerosene lamps in pitch dark conditions
of the villages. Any thing just better than the kerosene lamp at a
reasonably affordable cost should satisfy our requirements/efforts.
If the source of available energy is sufficient for running CFL /FL lamps
for 3 to 4 hours a day, we should definitely go for CFL/FL lamps. But
unfortunately this is not the case at present in many villages of the Third
World. Then what is the next alternative? Of course White LEDs.

I myself have conducted a few demonstrations of White LED lamps in the
villages of Nepal .I have lived with the villagers during the evening
periods ; and given the housewives , school teachers, shopkeepers,
hotelowners, healthpost technicians , etc. the portable white LED lamps for
comparative use. We unanimously found that White LED lamps were far better
than the kerosene wick lamps and even better than the hurricane type
kerosene lanterns. Housewives and the students liked them very much. These
white LED lamps were assembled locally and fitted with just 3 Nos of Nichia
(Japan) LEDs, each of 5,000 millicandela luminous intensity , powered by 3
Nos. of Ni-Cd rechargeable batteries connected in series.
In one demonstration a friend of mine from Vietnam, who is working in solar
home systems, was also present. Initially he did not like the White LED
lamps; but after the village level trial, he also appreciated the overall
usefulness of this low power illumination technology. LED illumination
technology has no doubt a very bright future; and its application is
finding more coverage even in Europe and America. Since White LEDs are now
manufactured in China and Taiwan, prices are coming down quickly enabling
the customers of the poor countries to enjoy evening light. Charging of
those lamps is done either by pedal power or by small solar PV module or by
the batteries of solar home systems owned by the richer families in the
village.

One of the main disadvantages of White LED lamp is that the light comes out
like a cinema projector; and behind the lamp it is almost dark. Viewing
angle of White LED is very low (in the range of 20 to 30 degree). We could
technically utilize the waste heat of cookstoves to run a 5 or 7 watt TEG
and using suitable DC-DC converters power the white LED lamps. But I
think TEG will be costlier that solar PV modules for the same range of power
output.

Regards

R. B. Adhikari

From tmiles at TRMILES.COM Wed Jun 9 22:08:15 2004
From: tmiles at TRMILES.COM (Tom Miles)
Date: Tue Aug 10 18:31:15 2004
Subject: University Stoves Interest in Nepal
Message-ID: <WED.9.JUN.2004.190815.0700.TMILES@TRMILES.COM>

Following is a message from Bryan Wilson to ETHOS regarding university stoves interest in Nepal. See his photos on the stoves website at
http://www.repp.org/discussiongroups/resources/stoves/Willson/nepalstoves.htm

Tom
----- Original Message -----
From: Bryan Willson
Sent: Wednesday, June 09, 2004 12:02 PM
Subject: University Stoves Interest in Nepal

All -

I'm currently in Kathmandu for a few more weeks working to help set up a Fulbright-funded hydrogen research laboratory at Tribhuvan University. Chandra Joshi from Tribhuvan visited Colorado State University in January on the same project and then accompanied me to the Ethos conference in Seattle. Chandra's son, Sachin, received in BS in Mechanical Engineering a year or so back and has since been working on a relatively large "improved cookstove" dissemination project in rural Nepal. I took Chandra to some "Engineers Without Borders" meetings while he was here, and his son Sachin then started a chapter after Chandra returned. Today, they held a meeting with a speaker on improved cookstoves from a local NGO (Center for Rural Technology) and almost 50 students showed up.

There is a recognition by many that the cookstoves currently being disseminated in Nepal (somewhere around 180,000 in the past few years!!) provide substantial health improvement (because of the use of a chimney), but provide little improvement in efficiency. In fact, due to high draft (perhaps from excessively tall chimneys) on some stoves, the wood usage often increases. Sjoerd Nienhuys is the Nepal representative for SNV, a Netherlands funding agency. He is aware of the potential efficiency improvements. Through the web he found the REPP stoves website, the Stoves listserve, and is aware of the Ethos group. I think he's posted a few times on the Stoves listserve. He is providing some funding to have the EWB student group fabricate some "rocket-like" stoves for evaluation in Nepal. [Interesting side note: Sjoerd told me he asked for a larger diameter for the firebox to allow use of bigger wood. I gave him what I could remember of Larry's arguments against large entry holes - including the problems of chimney fouling that Rogeria discussed in Seattle.]

Partway into the lecture, I started to think about the potential implications of a meeting like this. 50 engineering students in a developing country (with a huge need for new cookstove technology) asking very insightful questions about cookstove design. I snapped a few pictures and thought you folks might like to see them.

The students asked for a more technical discussion of stove design, so I've been enlisted to give some lectures next week on combustion, pyrolysis, gasification, and principles of stove design. I think I know enough to be dangerous, but could do a better job with a few diagrams, and slides with temperatures and such. If anyone has some PowerPoint slides and/or handout materials that they could e-mail that would really help. Since yesterday, all schools are "shut down" due to a general education strike called by the Maoist insurgency. The strike affects both "K-12" and higher education. The duration of the strike is indefinite so the students have lots of time to spend on this. I guess my lecturing doesn't count against the strike.

- Bryan Willson

_____________________________________________________

_______________________________________????______________

Dr. Bryan Willson

Professor of Mechanical Engineering

Research Director, Engines & Energy Conversion Laboratory

Department of Mechanical Engineering

Colorado State University

Phone: (970)-491-4783

Mobile: (970)-227-5164

Text Messaging: 9702275164@mobile.att.net

EECL Web Site: www.engr.colostate.edu/eecl/

Alternate Engines Lab Contact: Ms. Kathy Nugent - (970)-491-4785

From ventfory at IAFRICA.COM Thu Jun 10 03:35:02 2004
From: ventfory at IAFRICA.COM (Kobus)
Date: Tue Aug 10 18:31:15 2004
Subject: Simple charcoal stove designs?
Message-ID: <THU.10.JUN.2004.093502.0200.VENTFORY@IAFRICA.COM>

Dear Ken,

I also started experimenting with tin cans and found that the taller the
string of cans was (i.e. the more draft) the more visibly "cleaner" the charcoal
burned and the faster it started up. Off course, I was bottom-lighting at
the time with newspaper and was experimenting with small fuel loads. I
figured if I was going to design a stove for poor folks it had to use less
fuel and top lighting will be hard to do by uninformed users. The results
were encouraging as there was minimal PM in the smoke due to the fast
start-up time and small fuel charge. The burn duration was short-lived
though and I later learned that high amounts of CO was being released.
Adding more fuel at start-up and top-lighting it, coupled with better
insulation and separated primary and secondary air did make it safer to use
indoors though. Teaching top-lighting to people here was not so difficult
to do after all as they could visibly see less smoke in doing so, and paraffin,
relative cheap here was used in conjunction with newspaper. The tin can
set-up could be quite useful for outdoor barbeques, especially if you place a
wok on it, just make sure it does not fall over. The only remaining
problem is durability of the cans. Using a riser sleeve as insulation in
combination with tin can liners, like Tom Reed is doing seems to offer the best
solution. I may speak under correction but the fan on his stove supplies
the required airflow to the char mostly, as the natural airflow through the
stove is determined by the length of the chamber which is preset for biomass
burning. Increase the chamber to a fixed height for charcoal burning and you do not need a fan in my experience. Crispin's stove is an example of that, as his taller chamber allows for gasification of charcoal from start-up and of charred biomass
without forced draft. Brightcross Insulation Ltd in Derby, DE23 8XA, sells
1260 grade risers. Your 150 mm ID will work, but smaller down to 100 is
more preferred. The riser / tin can length is crucial though.

Regards

Kobus
South Africa

----- Original Message -----
From: Ken Boak <kenboak@STIRLINGSERVICE.FREESERVE.CO.UK>
To: <STOVES@LISTSERV.REPP.ORG>
Sent: 09 June 2004 02:05
Subject: [STOVES] Simple charcoal stove designs?

> Stovers,
>
> Today the temperature in London reached 29 C in the shade at noon, which
> encouraged me to try some simple charcoal stove ideas tonight using my
cheap
> Chinese pot-bellied barbeque - a cast iron pot about 20cm (8") in
diameter,
> a 20cm grate and with a wok-like top and a cast-iron grid.
>
> I have a supply of excellent English lumpwood charcoal, thanks to fellow
> Stover David Reynolds Lacey.
>
> I tried some boiling tests using an 18cm stainless steel pan, with a 1cm
> steel plate on the bottom and a glass lid.
>
> My first test was 1 lite of water and 250g of potatoes and 3g of salt. In
> the unmodified barbeque with an 20cm (8") diameter of burning charcoal
> the pot boiled in 15 minutes exactly.
>
> After eating, I tried to make a more compact 15 cm (6") charcoal burner
from
> an old coffee tin. Sadly the boil time for 1250 ml of water increased to
22
> minutes.
>
> I tried a 15cm diameter sleeve made from perforated steel sheet to contain
> the charcoal in a makeshift brazier and this seemed to work OK as long
as
> the fuel level was kept up close to the bottom of the pan.
>
> Should I be looking towards riser sleeves for this type of stove - if so
> what diameter.
>
> Can I burn charcoal efficiently without forced draught?
>
> Here are some facts and figures:
>
>
> Fuel type: English lumpwood charcoal
> Fuel Charge: 325g
> Cold water starting temp: 15.5 C
> Pot diameter: 18 cm
> Pot height 8.5 cm. and 1cm thick steel bottom.
> Volume of water 1250ml
> Best boil time: 15:00 minutes
> Altitude 30m above sea level
> Ambient temp 22 C
>
> If anyone can advise me how to make a tincan stove for better burn
> efficiency of charcoal I would love to hear some practical advice.
>
>
> regards,
>
>
> Ken
>
> (London)

From hseaver at CYBERSHAMANIX.COM Thu Jun 10 10:01:56 2004
From: hseaver at CYBERSHAMANIX.COM (Harmon Seaver)
Date: Tue Aug 10 18:31:15 2004
Subject: Absortion chillers using our heat
In-Reply-To: <003901c44d2e$7c7fc840$cb83fea9@md>
Message-ID: <THU.10.JUN.2004.090156.0500.HSEAVER@CYBERSHAMANIX.COM>

I've worked on a number of old propane and kerosene fridges, and don't see
anything dangerous about them. Some have blown the refrigerant due to rusted
coils and it was no big thing, just a "pop" and "hiss". The icy-ball design
looks a bit more hazardous, but I would certainly think that a simple, safe,
cheap design could be created. I'm surprised at the regs there -- no such
problem here in the ultra-safety-paranoia US that I know of, perhaps for
commercial refrigeration units, but certainly not for home ones, AFAIK.

On Tue, Jun 08, 2004 at 09:59:06AM +0200, Crispin wrote:
> Dear Stove-powered refrigerators
>
> Around here you are not allowed to use commercially or sell a heat-powered
> device (or air compressor) that operates at a pressure above 4 Bars
> (atmospheres) unless it is inspected (inside) annually by a certified
> inspector of pressure vessels.
>
> As the ammonia fridge runs at pressures up to 240 psi (intimidating enough
> as that is for the experienced craftsman) I doubt that it is a low cost
> option for rural areas, even though the technology seems most suitable in
> principle.
>
> Regards
> Crispin

--
Harmon Seaver
CyberShamanix
http://www.cybershamanix.com
Hoka hey!

From psanders at ILSTU.EDU Thu Jun 10 13:31:13 2004
From: psanders at ILSTU.EDU (Paul S. Anderson)
Date: Tue Aug 10 18:31:15 2004
Subject: Lemon Light...by night
In-Reply-To: <000001c44ce6$9319b0e0$e49dfea9@home>
Message-ID: <THU.10.JUN.2004.123113.0500.PSANDERS@ILSTU.EDU>

Crispin and Stovers,

S L I C K !!!!

Your written description is so good that I (with the picture) am able to
understand it.

Just imagine one side (6 cubes) of an ice cube tray with lemon juice, then
wires of appropriate metals (that do not touch each other) connecting them
in series alone the tray. He has a battery booster because of the
metals/size, but otherwise the + and - ends are connected to the LED, and
the light goes on.

Definitely worth further experimentation. I will do some of the
experiments. I assume that galvanized (zinc coated steel) and some lead
sheeting would be best. Surface area is important (but I cannot calculate
what areas might be appropriate, so just trial and error unless someone
else can provide that info. Thanks in advance.)

Concerning taking apart old car batteries, does anyone have experience (or
inclination) to do something about that option.

Just remember, to objective is to get just enough power to run some LEDs or
a very small motorized fan/blower. Tom's Woodgas Campstove uses a 1.5 volt
AAA battery and is said to need 1 watt of power to drive a 4 inch diameter
fan blade.

Where we want to use this device, you can assume that the acid needed
literally "grows on trees."

Crispin, please remember to tell us how long the light keeps burning.

Paul

At 01:24 AM 6/8/04 +0200, Crispin Pemberton-Pigott wrote:
>Dear Paul
>
>The Lemon Light Ice Cube Tray Battery
>
>I attempted to wrest a set of red and green LED's from a Toshiba
>Satellite Pro (which I might add is a laptop you should not ever try to
>open with anything less than a hammer) and a couple of cuts and bruises
>later I had the power control panel in my hand and a large number of
>broken parts scattered on the floor. The board has several LED's on it.
>
>I tested them by hooking a single 1.6 volt dry cell battery (a new one)
>in series with a brake light bulb (12 ohms). If I had a soldering iron
>at home it would have been easier. Nothing at all happened.
>
>I tried two dry cells in series and the LED's worked very well (one or
>two at a time) and did not burn out. It absolutely would not work with
>one battery so clearly the forward breakdown voltage is between 1.6 and
>3.2 volts. Perhaps it is 2 volts at a minimum. By this time I really
>wished I had a soldering iron.
>
>The LED's worked well and did not blow. They were pretty bright. If
>the forward breakdown voltage is 2 volts, then the current flowing is
>1.2v/12 ohms = 100 ma which seems a bit high. If the breakdown voltage
>is 2.5v the current flowing is 0.7v/12 ohms = 58ma which is believable.
>
>Next, I found some tinned copper wire (silver in colour but copper
>inside). Knowing this is not as good as a galvanized wire I proceeded
>because that is all I could find in the junk box. I made 6 small
>rectangles with one end poking up and sat each on in the 'cell' of a
>plastic icecube tray.
>
>Next, I made a smaller rectangle out of some thick solder (lead+tin) and
>sat one in each cell so that it did not touch the copper wire and
>connected each pair to make a 6 cell copper/lead battery.
>
>Next, I went into the garden and picked a large lemon from the tree in
>the round flowerbed off the patio and sliced it in two. I squeezed the
>juice out and added it to the cells putting in the pulp as well hoping
>that it might keep things acid.
>
>Then I connected the two output wires to a pair of multimeter leads (the
>meter itself having disappeared some time ago). With these two leads I
>connected the Lemon Light battery to the LED panel.
>
>Nothing at all happened. I reversed the leads and still a complete
>blank. Not enough voltage.
>
>Next I put one of the dry cells in series with my battery to see if mine
>would give it enough of a boost to start the current flowing. This was
>successful and the lights would blink on as I rubbed the lead up and
>down the multi-lead strip that the manufacturers used to plug the panel
>into the motherboard.
>
>I was able to hold the power wire onto two contacts at the same time and
>both of the LED's lit up. The illumination was weak (low current)
>however my generating area was no more than 280 sq mm per cell.
>
>I did manage to get a photograph of the LED working by turning off the
>room light and raising the brightness of the resulting JPG. I am
>attaching a photo of the whole device and the picture taken in the dark
>which you, Paul, will receive but which will get stripped from the
>message posted to the group. In case you were wondering, the thing for
>taking stones out of horses hooves on the Swiss Army knife is clamping a
>thin solder wire onto the common lead and the black lead is lying on one
>of the green LED's contact. The other contacts are twisted and the
>battery is taped to its leads.
>
>Conclusion:
>The 6-Cell Lemon Light Battery was generating 1 volt in spite of the
>very poor choice of metals. When put in series with the 1.6 volt dry
>cell it was able to illuminate 2 small LED's which probably require 2.5
>volts to fire.
>
>I have built Lemon batteries in Abidjan using only wires (copper and
>galvanized steel) plugged into lemons and used them to run a 1.5 volt
>clock. The typical clock requires 2 banks of 6 lemons in series.
>
>I will leave my Lemon Light runing to see what happens in the next few
>days.
>
>It occurred to me today that one of the best ways to make such a cell in
>a remote location with enough power to run a small fan or LED's is to
>take an old car battery apart with a hacksaw and make two double cell
>batteries, or more appropriately, separate and use only two of the
>plates and make many batteries of two plates each! Of course it will
>help to have a citrus tree nearby...
>
>Illuminatingly yours,
>Crispin
>

From psanders at ILSTU.EDU Thu Jun 10 13:35:15 2004
From: psanders at ILSTU.EDU (Paul S. Anderson)
Date: Tue Aug 10 18:31:15 2004
Subject: Absortion chillers using our heat
In-Reply-To: <003901c44d2e$7c7fc840$cb83fea9@md>
Message-ID: <THU.10.JUN.2004.123515.0500.PSANDERS@ILSTU.EDU>

Crispin and All,

JUST for modest cooling (but not freezing), are there any options at
sufficiently low pressures that safety is possible?

Paul

At 09:59 AM 6/8/04 +0200, Crispin wrote:
>Dear Stove-powered refrigerators
>
>Around here you are not allowed to use commercially or sell a heat-powered
>device (or air compressor) that operates at a pressure above 4 Bars
>(atmospheres) unless it is inspected (inside) annually by a certified
>inspector of pressure vessels.
>
>As the ammonia fridge runs at pressures up to 240 psi (intimidating enough
>as that is for the experienced craftsman) I doubt that it is a low cost
>option for rural areas, even though the technology seems most suitable in
>principle.
>
>Regards
>Crispin

From crispin at NEWDAWN.SZ Thu Jun 10 17:24:25 2004
From: crispin at NEWDAWN.SZ (Crispin Pemberton-Pigott)
Date: Tue Aug 10 18:31:15 2004
Subject: RE Lemon Light...by night
Message-ID: <THU.10.JUN.2004.232425.0200.>

Dear Paul

Thursday night - the light is still on.

Regards
Crispin

From crispin at NEWDAWN.SZ Thu Jun 10 17:24:25 2004
From: crispin at NEWDAWN.SZ (Crispin Pemberton-Pigott)
Date: Tue Aug 10 18:31:15 2004
Subject: Absortion chillers using our heat
Message-ID: <THU.10.JUN.2004.232425.0200.>

Dear Paul

>JUST for modest cooling (but not freezing), are
>there any options at sufficiently low pressures
>that safety is possible? [ammonia+water fridge]

I have been giving this a little thought and there is another option
that has not been done as far as I know.

There is a roaring trade around here in what are called "TV Batteries"
which are brought in once a week and charged, often at petrol stations
and battery dealers. They often have 20 to 30 charging at once. They
charge about $1.50 for the service. The batteries are basically car
batteries with handles attached on top so they are easily transported.
They probably have a little extra gap under the plates so that powder
and junk falling off the plates (which happens each time it is charged,
discharged and hammered around) does not short out the plates before the
guarantee expires.

It is interesting to note that a Canadian Tire 5 year guarantee battery
is a 3 year guarantee battery with more free space under the plates!

Anyway, that is my model. People are using 'electricity' at home -
millions of them - using stored power in lead-acid batteries.

So...why not a portable ammonia fridge 'charging' business? It is not
the whole mechanism that needs to be charged, basically, the system
works by absorbing the ammonia, not necessarily by using the same water
over and over. Because the separation is not done in the fridge, the
pressure at which the systems runs would be very low - probably less
than 1 bar positive.

If the water+ammonia can be returned to the shop for a refund, the
ammonia can be removed and and ammonia pack sold in exchange. You would
need to actually get or rent your own container - just a bottle of
ammonia. To get you money back you need to bring in your water+ammonia
'discharged' cell.

The shop would have a system for safely separating the ammonia from the
water and it could be done slowly or in a large cheap lower pressure
process involving bubblers or stirrers etc.

Even a modest amount of ammonia (with a hydraulic quick-disconnect type
connector as you see on tractors) would keep a small fridge cool for a
week.

Obviously there are transport isues, but perhaps all you need is a
wheelbarrow and a shop with the separating equipment in the
neighbourhood to bring safe refrigeration to an entire community.

A nice project, and not much actualy science to find out, only the
implementation.

Regards
Crispin

From psanders at ILSTU.EDU Thu Jun 10 17:49:25 2004
From: psanders at ILSTU.EDU (Paul S. Anderson)
Date: Tue Aug 10 18:31:15 2004
Subject: Absortion chillers using our heat
In-Reply-To: <6.1.1.1.2.20040606172538.02d00b58@pop.sonic.net>
Message-ID: <THU.10.JUN.2004.164925.0500.PSANDERS@ILSTU.EDU>

Matthew,

I had not seen this before. The second reference ( ...pdf ) is
exceptionally interesting. My question now is:

Instead of a solar collector to heat the zeolith, the heating could be
accomplished by some small stove.

Matthew, are you "into this stuff" enough to want to do some
development? Is anyone else interested? Reply either via the list serve
or directly to me "off-list".

Paul

At 05:48 PM 6/6/04 -0700, Matthew Takeda wrote:
>Paul S. Anderson wrote:
>>NOW my question is, what can be made at LOW cost for developing
>>countries? I am thinking of cool, not cold, (to freeze water would be
>>nice, but that is not as important as cool so that milk, etc does not spoil.)
>
>Paul -
>
>Have you looked into intermittent zeolite sorption cooling?
>
><http://www.eg-solar.de/english/products/solarrefrig.htm>
><http://193.175.120.23/an/pt/solar/publish/euros-00.pdf>
>
>
>Matthew Takeda
>the JOAT

From LButtner at WINROCK.ORG Thu Jun 10 17:44:20 2004
From: LButtner at WINROCK.ORG (Lisa Buttner)
Date: Tue Aug 10 18:31:15 2004
Subject: [ethos] Partnership for Clean Indoor Air
Message-ID: <THU.10.JUN.2004.174420.0400.LBUTTNER@WINROCK.ORG>

Dear Dean and Friends,

I wholeheartedly endorse Dean's encouragement to all of you to help grow
the Partnership for Clean Indoor Air. It is largely due to the work
that so many of you do that will enable the Partnership to make a
difference in people's lives.

I would just like to point out that the link Dean provided gives a
summary page on the Partnership. The PCIA website, including Partners,
events, etc., is now live and will be evolving: www.pciaonline.org
Please send your comments and suggestions on how this site can best
serve you in your efforts!

Best,

Lisa

-----Original Message-----
From: Dean Still [mailto:dstill@epud.net]
Sent: Sunday, May 30, 2004 11:25 AM
To: STOVES@LISTSERV.REPP.ORG; ethos@vrac.iastate.edu; 'Grant
Ballard-Tremeer'; mitchell.john@epamail.epa.gov
Subject: [ethos] Partnership for Clean Indoor Air

Dear Friends,

Many of us know the EPA folks at the Partnership for Clean Indoor Air.
The Partnership, responding to the UN resolution that indoor air
pollution caused by combustion must be reduced, has done a great job
creating a powerful coalition worldwide. I think that most members of
our stove community have had some exposure to their work. I see a much
more active interest in stoves these days which often constellates
around the Partnership.

We can make this effort more successful by bringing in new members:
countries, organizations, ngo's, non profits. Membership is free,
brochures are available from John Mitchell or print out the web page...

mitchell.john@epamail.epa.gov

I hope that we can pass around the information and double the size of
the Partnership each year. Here is the web page address:

http://www.epa.gov/iaq/pcia.html

Please make the connection personally and have the organization contact
John or the PCIA.

Let's help the millions who need better stoves!

Best,

Dean

---
To unsubscribe, send email to majormail@vrac.iastate.edu with this as
the first line in the BODY of the message: unsubscribe ethos
---

From list at SYLVA.ICUKLIVE.CO.UK Thu Jun 10 17:55:53 2004
From: list at SYLVA.ICUKLIVE.CO.UK (Andrew Heggie)
Date: Tue Aug 10 18:31:15 2004
Subject: White LED and CFL Lamps
In-Reply-To: <BAY22-DAV18KpRcTCi90000213e@hotmail.com>
Message-ID: <THU.10.JUN.2004.225553.0100.>

On Wed, 9 Jun 2004 21:19:40 -0400, Rajendra B Adhikari wrote:

> >>
>
> First of all we should be clear that our main goal is to replace the
>existing kerosene lamps or the pine rosin lamps used by the poor people in
>the developing world, and not in Europe or in America.

Rajendra this I understand.
<snipped experience of LED use>

>One of the main disadvantages of White LED lamp is that the light comes out
>like a cinema projector; and behind the lamp it is almost dark. Viewing
>angle of White LED is very low (in the range of 20 to 30 degree). We could
>technically utilize the waste heat of cookstoves to run a 5 or 7 watt TEG
>and using suitable DC-DC converters power the white LED lamps. But I
>think TEG will be costlier that solar PV modules for the same range of power
>output.

I imagine you are right, we still have to consider the cost of the
rechargeable battery and its efficiency compared with the teg which
might make power as it is needed. I still wonder if the life of a
nicad battery justifies its environmental cost, in the absence of
sensible reuse of its components.

I received this comment off list:

"Just to mention that with a Canadian group more than a 100 units were
installed in a faraway village in Peten department of Guatemala . More
than 200 in Bolivia and more than 250 in Peru. All contain a Solar
Cell, a recharable battery and two fixtures containing 13
WLEDs.operating on 12volts DC"

I'd like to know a bit more about the costs and life of these lights
and how they fared if DC would care to follow up on this.

AJH

From pverhaart at IPRIMUS.COM.AU Fri Jun 11 07:17:17 2004
From: pverhaart at IPRIMUS.COM.AU (Peter Verhaart)
Date: Tue Aug 10 18:31:15 2004
Subject: Absortion chillers using our heat
In-Reply-To: <000001c44f31$6a096950$e49dfea9@home>
Message-ID: <FRI.11.JUN.2004.211717.1000.PVERHAART@IPRIMUS.COM.AU>

Crispin,

You mention yearly tests for pressure vessels. Does that apply to
vessels of any size? Your ammonia idea, if I understand it, involves a
cylinder of ammonia, The liquid ammonia expands through a capillary into
the cold part, the so-called evaporator. The low pressure is provided by
water in which ammonia gas dissolves readily. The water has to be cooled as
the absorption is exothermic. From Google the pressure of liquid NH3 at 70
F is 114 psi or 7.85 bar.
If no freezing is required you could think of ammonium nitrate or even
urea. When the crystals are dissolved in water the solution falls in
temperature. Recovery by letting the solution evaporate in the sun.

Peter Verhaart

At 23:24 10/06/2004 +0200, you wrote:
>Dear Paul
>
> >JUST for modest cooling (but not freezing), are
> >there any options at sufficiently low pressures
> >that safety is possible? [ammonia+water fridge]

From rmiranda at INET.COM.BR Fri Jun 11 07:58:26 2004
From: rmiranda at INET.COM.BR (Rogerio Carneiro de Miranda)
Date: Tue Aug 10 18:31:15 2004
Subject: plancha vs open fire
In-Reply-To: <20040609164854.766F175C@telchar.epud.net>
Message-ID: <FRI.11.JUN.2004.085826.0300.RMIRANDA@INET.COM.BR>

Dean, A.D. Karve, et al:

In Nicaragua we have commonly seeing that plancha stove can save up to 60%
in fuel in comparation to open fires, if use wisely. It better performs if
you use as much as of the griddle area and for as long as possible, then
the savings is great. Of course just boiling water for coffee you dont see
any energy neither saving time..

Other advantages of the plancha as mentioned by Dean, is the clean
environment, no sot neither smoke indoors, and its multiple use. I called
it a heat extractor, which transfered to the griddle the heat, can be used
by the cooker as pleased, cooking with many smaller pots, or just one
large pot, or even cook directly on it as pancakes, tortillas, tapiocas
and barbecue..It also can be a space heater, since the really hot griddle
radiates heat into the room. The idea behind the plancha stove (Dona
Justa or Ecosotve) is that what we want from he wood is its energy as
heat, not the smoke neither the sot....

Here in Brazil we are these days presenting for the first time the Ecostove
to the public, trough the Minas Gerais agriculture state fair and it is
amazing how people really admire the new features and concepts of the
Ecostove: savings and clean. The traditional woodstove used here in Minas
Gerais for the past 50 + years is the plancha stove, the same stove as you
might know from Guatemala, the model being used by Kirk Smith in
his research there. However many urban families here has abandoned its
use due the smoke exposured, which even though is much less than open fire
for instance. At the AG fair, many mid class urban families has
manifested their interest now to have a woodstove again with the Ecostove,
because it is portable, compact, clean and use minimial firewood, which is
hard to find in urban settings.. Of course for them the Ecostove is a
complement or combination with the GLP stove, to save in GLP (which price
is increasing slowly) and to have the pleasure of wood cooking. Here in
Minas there is a culture of woodstoves, people really enjoy cooking with
woostoves in weekends in their back yards as recreational, having the
family around, drinks and enjoy the better tasted food...

Here at my home for instance, one 13 kg GLP (US$ 10,00 ea) cylinder would
last 21 days before installing the Ecostove, but now for the past 14
months using the Ecostove to prepare the lunch meals everyday, the GLP
cylinder last about 5 months, while I spend only US$ 5,00 in firewood per
month ( mostly 3 bags).

Cheers

rogerio

At 13:48 9/6/2004, Dean Still wrote:
>Dear Friends,
>
> > A.D. Karve said," I always
> > thought that placing a pot on the Plancha stove would be less
> > efficient than placing the pot directly on the fire."
>
>We have done a lot of experiments here and in Central America with plancha
>stoves. A cold plancha or griddle can take a longer time to boil water
>compared to an open fire. But, a red hot spot on the plancha in contact with
>a pot can boil the water slightly faster than an open fire. The expertly
>operated open fire can be a lot more fuel efficient compared to a cold start
>boil on a plancha stove. Plancha stoves can be made to efficiently heat the
>griddle but if only one pot is on the griddle a lot of the heat is wasted.
>
>Plancha stoves are inherently inefficient compared to stoves that force the
>hot flue gases to scrape against the bottom and sides of the pot. We use
>plancha designs in Central America because folks insisted that pots stay
>clean. The small fuel magazine plus cooks using multiple pots made the
>plancha fuel saving compared to very badly made open fires, the practice in
>many communities. But the optimized stove is twice as fuel efficient
>compared to the plancha. 17% PHU vs 35% PHU. (Tami Bond scored around 30%
>PHU with her award winning open fire test.)
>
>Studies show that the plancha stove saves a lot of wood in practice but it
>is a compromise and has some trade offs due to consumer preference.
>
>All Best,
>
>Dean

From crispin at NEWDAWN.SZ Fri Jun 11 19:16:55 2004
From: crispin at NEWDAWN.SZ (Crispin Pemberton-Pigott)
Date: Tue Aug 10 18:31:15 2004
Subject: Lemon Light
Message-ID: <SAT.12.JUN.2004.011655.0200.>

Dear Stovers Working by Night

I have become bored waiting for the battery to run down and suspicious
that the light was running on the dry cell battery even though it
doesn't have enough voltage to turn it on. So I brought a multimeter
from work to see how the system was performing.

As he helpers at work had been using the meter and left it turned on the
9 volt battery was dead so I first have to locate a 9 volt power suppy
in the junk room, otherwise known as my study. Wiring this into the
multimeter was accomplished with a Swiss Army knife and I was in action.

There were several remarkable things I discovered about the Lemon Juice
battery made in an ice cube tray.

The first was the enormous difference in voltage produced by he
different cells - a factor of 12:1 is some cases. It was clear before
long that the difference was the presence or otherwise of the fruit
pulp. Fruit pulp is apparently a very good insulator. When I took the
lemon pulp out of the cells the current went up by a factor of 5 or 7.
So there is a good piece of information - use juice!

The next surprise was that the voltage started FAR higher than it was
when it was running. This is not so surprising as it is a chemical
reaction that is being captured, but still, the no-load voltage went up
to 1560 mV while under load it dropped to 160 mV for 6 cells.

The current was surprisingly low. When initially connect there was a
surge of current of about 450 microamps which then settled at 140
microamps as the voltage dropped. That was the current lighting up the
LED.

I made two cells using bronze and aluminum by taking a heat sink out of
the ill-fated Toshiba and breaking off a rectangular piece and forming
it to the bottom of the ice cube cell. On top of this I put a small
piece of cloth cut from one of my older shirts and then put in a coil of
bronze wire which I de-coiled from an old guitar string (the E string if
you are interested).

These cells put out a remarkable 560 mV each under no load.

Conclusion:

The lemon cell boosting a dry cell battery works by building up a much
higher voltage than it can sustain when connected to a load - rather
like a chemical capacitor. This initial burst of voltage and current
can overcome the forward breakdown voltage of the LED and get the
current to flow. Once it is flowing, the current from the dry cell
battery was keeping the system going, almost entirely. The voltage
supplied by the lemon juice cells was reduced to a trickle, but was
still required.

Without the lemons it LED would not start, but it is possible that it
would continue without it, so when I tried shunting it out The light
went out, i.e. the LED could not keep going on 1.45 volts from the
battery.

The power generated by the lemons was 10 to 20 milliwatts on a
continuous basis, but without its voltage kick, the LED would not start
and run. Most interesting.

Regards
Crispin

From list at SYLVA.ICUKLIVE.CO.UK Fri Jun 11 19:42:26 2004
From: list at SYLVA.ICUKLIVE.CO.UK (Andrew Heggie)
Date: Tue Aug 10 18:31:15 2004
Subject: Lemon Light
In-Reply-To: <000001c4500a$34c4e330$e49dfea9@home>
Message-ID: <SAT.12.JUN.2004.004226.0100.>

On Sat, 12 Jun 2004 01:16:55 +0200, Crispin Pemberton-Pigott wrote:

>
>The next surprise was that the voltage started FAR higher than it was
>when it was running. This is not so surprising as it is a chemical
>reaction that is being captured, but still, the no-load voltage went up
>to 1560 mV while under load it dropped to 160 mV for 6 cells.
>

Doesn't this just point to a high internal resistance?

How much of the metal electrodes are being consumed?

AJH

From psanders at ILSTU.EDU Fri Jun 11 14:19:08 2004
From: psanders at ILSTU.EDU (Paul S. Anderson)
Date: Tue Aug 10 18:31:15 2004
Subject: plancha vs open fire
In-Reply-To: <000001c44e6b$daaacb70$e49dfea9@home>
Message-ID: <FRI.11.JUN.2004.191908.0100.PSANDERS@ILSTU.EDU>

Stovers. (I am not in Africa, but using a computer that thinks that I am
there.)

Quoting Crispin Pemberton-Pigott <crispin@newdawn.sz>:

> snip

> Where one wants extra heat on the disc part of the time and normal heat
> the rest, two or more thin(er) discs can be placed into the hole. They
> conduct heat less efficiently from one to another than a solid disc.
>
Could we get a desired result (of some type yet to be defined) if the
replacement disks were made of different materials. I am thinking of

a copper disk for quicker heat transfer

an aluminum disk (??) might not take the heat in some part of the stove, but
might work elsewhere.

a ceramic disk

a disk with a special shape (such as concave) to match a particular pot

an insert (not even a disk, but an insertable chamber that hangs down into the
path of the heat) such as a "well" for water to be quickly brought to a boil)

a disk with a special bottom such as

fins to redirect the heat flow to the sides,

or copper tubes/coils that connect to a gravity-fed hot water heater.

IF this makes sense, then the size of the hole (and the disks) could be larger
so that more types of disks could be used with the same hole. Big pots and
little pots could have their corresponding disks. (We have seen concentric
rings used in this way for a few hundred years to accommodate different sizes
of pots.)

Paul

------------------------------------------------------------
Illinois State University Webmail https://webmail2.ilstu.edu

From list at SYLVA.ICUKLIVE.CO.UK Sat Jun 12 10:19:17 2004
From: list at SYLVA.ICUKLIVE.CO.UK (Andrew Heggie)
Date: Tue Aug 10 18:31:15 2004
Subject: Flaming Resin For Jumla
In-Reply-To: <20040604221333.59898.qmail@web41606.mail.yahoo.com>
Message-ID: <SAT.12.JUN.2004.151917.0100.>

On Fri, 4 Jun 2004 15:13:33 -0700, Rajendra Adhikari wrote:

>Dear Stovers
>
>I am giving below the composition of pine resin usually found in Jumla, Nepal:
>
>The pine species are: (a) Pinus roxburghii and (b) Pinus wallichiana. The oleoresin on distillation yields about 16-20%w/w turpentine oil and 76-80% solid resin.
>Gas Liquid chromatography analysis of turpentine oil is roughly as follows:
>Hydrocarbons Mol. Formula %
>Delta-3-carene C10H16 48.90
>Alpha PInene C10H16 27.97
>Beta Pinene C10H16 16.07
>Para Cymene C10H14 6.83
>Gamma Terpinene C10H16 0.23
>Limonene C10H16 Trace
>
>May be somebody will find it useful to make smokeless resin lamp.
>

I suspect we all went quiet about this when we realised the resin
harvesting was not sustainable and led to the death of the tree, I
realised it was damaging but assumed the tree was harvested after the
ability to harvest resin was uneconomic because the bark was so
wounded.

Anyway I have done some further experiments.

Firstly
http://people.ouc.bc.ca/woodcock/molecule/modelfiles/c10h16.html

seems to have an applet that could be useful to view molecules,
unfortunately I have not located the plug ins or browser that can view
it, any ideas?

Secondly

<http://environmentalchemistry.com/yogi/chemicals/formula/C10H16%20(approx).html>

suggests this is a fairly nasty compound, any views on this?

I loaded a small amount of resin into a small brass cylinder sealed at
on end (these are readily available throughout most of the world :-().
Then I added a brass top with a slit from a paraffin burner, this is
one of the many bits of useful junk we acquired from a friend Kit
Wallis along with my manometer, lucas apu and the beginnings of a gas
turbine built with a lorry turbocharger.

I pre heated the reservoir until smoke came from the slit and then lit
this. It was a smoky flame with the soot forming strings of carbon
floating away. The flame did not burn clear until it was only 5mm
tall. This suggests that even with a number of holes along a thin
horizontal tube the light when the flame was clean burning would be
low.

http://www.wokingnursery.co.uk/resin/nosmoke.jpg
http://www.wokingnursery.co.uk/resin/nosmoke2.jpg

My thoughts on this are:

It is a nasty chemical to burn and the PICs are likely to be PAHs
which are worse than wood smoke.

From solar1 at ZUPER.NET Sat Jun 12 11:24:27 2004
From: solar1 at ZUPER.NET (Fundacion Centro para el Desarrollo con Energia Solar)
Date: Tue Aug 10 18:31:15 2004
Subject: Lemon Light
In-Reply-To: <000001c4500a$34c4e330$e49dfea9@home>
Message-ID: <SAT.12.JUN.2004.112427.0400.SOLAR1@ZUPER.NET>

Dear Crispin,
Your resent writing is very entertaining and enjoyable reading.
in a previous message, Crispin Pemberton-Pigott on 6/11/04 19:16 at
crispin@newdawn.sz wrote:

> Dear Stovers Working by Night
>
> I have become bored waiting for the battery to run down and suspicious
> that the light was running on the dry cell battery even though it
> doesn't have enough voltage to turn it on. So I brought a multimeter
> from work to see how the system was performing.
> Regards
> Crispin
>

--
"Just remember we have enlisted for the duration in service to the truth."
Chuck Colson's friend

David Whitfield

solar1@zuper.net
aguaviva@zuper.net
dewv@yahoo.com

http://www.solarcooking.org/media/broadcast/whitfield/bio-whitfield.htm

http://www.thehungersite.com

From pverhaart at IPRIMUS.COM.AU Sun Jun 13 00:17:08 2004
From: pverhaart at IPRIMUS.COM.AU (Peter Verhaart)
Date: Tue Aug 10 18:31:15 2004
Subject: Absortion chillers using our heat
In-Reply-To: <007701c44fd6$9c25b8d0$d3c3f204@7k6rv21>
Message-ID: <SUN.13.JUN.2004.141708.1000.PVERHAART@IPRIMUS.COM.AU>

Art,
Just as I thought. there is a lower limit to the size of pressure
vessels that have to comply with the regulations. On reflection the
pressure of 240 psi Crispin mentioned seems rather high. Not possessing a
Mollier chart for Ammonia I can't say for sure but if the saturation
pressure at 70 F is 114 psi, surely it would not increase more than 100 psi
in the next 30 F.

Peter Verhaart

At 10:07 11/06/2004 -0700, you wrote:
>Peter,
>
>I believe the way the absorption refrigerator gets through without the
>annual inspection is that they are below the radar screen for pressure
>vessels.
>
>There are at least three codes involved in the design of pressure containing
>vessels. There are fired vessels (boilers), pressure vessels and piping,
>each with their own regulations. Because most of the refrigerant is in
>tubing and not in a large volume vessel, they do not meet the requirements
>to be considered a "pressure vessel". They must meet piping or tubing codes
>which do not carry the annual inspection requirement. The industry has
>corrosion resistance requirements but knowledge in that area is quite old
>and well understood. The operating temperatures are only moderate so that
>does not trigger safety requirement for the annual "pressure test" either.
>
>Art Krenzel

From phoenix98604 at EARTHLINK.NET Sun Jun 13 01:47:35 2004
From: phoenix98604 at EARTHLINK.NET (Art Krenzel)
Date: Tue Aug 10 18:31:15 2004
Subject: Absortion chillers using our heat
Message-ID: <SAT.12.JUN.2004.224735.0700.PHOENIX98604@EARTHLINK.NET>

Peter,

The absorption refrigerator produced here in the US uses a gas mixture of hydrogen and ammonia in a water solution and depending upon the reservoir temperature can have a pressure varying from:

Vapor pressure in psig
70 degrees F: 127
100 degrees F: 196
105 degrees F: 210
130 degrees F: 287

See www.rvmobile.com

Art
Art,
Just as I thought. there is a lower limit to the size of pressure vessels that have to comply with the regulations. On reflection the pressure of 240 psi Crispin mentioned seems rather high. Not possessing a Mollier chart for Ammonia I can't say for sure but if the saturation pressure at 70 F is 114 psi, surely it would not increase more than 100 psi in the next 30 F.

Peter Verhaart

From dstill at EPUD.NET Sun Jun 13 12:36:55 2004
From: dstill at EPUD.NET (Dean Still)
Date: Tue Aug 10 18:31:15 2004
Subject: Absortion chillers using our heat
In-Reply-To: <003201c45109$ff512500$51baf204@7k6rv21>
Message-ID: <SUN.13.JUN.2004.093655.0700.DSTILL@EPUD.NET>

Dear Friends,

Larry and I spent two years building prototypes of ammonia absorption
refrigerators. We found an Icy Ball in a museum and patterned our
experiments after it. We also had the patent drawings and a bunch of books.
There are several hidden tricks necessary to making the Icy Ball function
not obvious in the descriptions.

Mostly you need to strip the water when you are boiling off the ammonia and
then, have all the right angles when tipping the left over weakened ammonia
water back into the boiling container. It was not an easy job for us.

Our number 15 prototype cooled 18 pounds of water 45 degrees using 8 pounds
of ammonia after a 45 minute heating using a 14 Kw burner.

Larry eventually thought that the Icy-Ball was too dangerous for general
use. We had a pressure gauge and saw 300 psi during hot weather. We have
very cool water in Oregon to help dissipate heat but not so in the tropics.
It could blow up if the user forgot to take it off the heat after the
ammonia boiled over.

Luckily, there is a factory very close to us that repairs Servel
refrigerators. The Servel system uses only tubing which can withstand high
pressure. It is a constant system not cyclical requiring if I remember
properly only 1400 watts of heat supplied in propane refrigerators by a
small flame.

One of these days we would like to get the working parts from the nearby
factory and run the Servel on solar. Shouldn't be too hard unless we forgot
something. If a student wants to do it, I'll get you the parts, you can live
at Aprovecho and do the development...should take less than a year.

All Best,

Dean

From psanders at ILSTU.EDU Sun Jun 13 16:56:34 2004
From: psanders at ILSTU.EDU (Paul S. Anderson)
Date: Tue Aug 10 18:31:15 2004
Subject: Lemon Light
In-Reply-To: <000001c4500a$34c4e330$e49dfea9@home>
Message-ID: <SUN.13.JUN.2004.155634.0500.PSANDERS@ILSTU.EDU>

Crispin,

Very interesting. Now help me understand where this is taking us. Can we
get meaningful power (micro-power) from the "lemon light" concept?

You wrote:
>The current was surprisingly low. When initially connect there was a
>surge of current of about 450 microamps which then settled at 140
>microamps as the voltage dropped. That was the current lighting up the
>LED.

If 140 microamps is sufficient (plus presence of a small battery that seems
to be needed but not actually being consumed by the LED), THAT seems to be
significant considering the "ice cube tray plus wire" of this early testing.

Is it a question of size of the container of juice and area size of the two
metal "plates" in each power cell?

And what amount of power is needed? 1000 microamps to get one amp,
right? What can we do with 1 amp? or with 1/10th amp? I am after the
power to run a very small motor to drive a fan like in Tom's Woodgas
Campstove. What are the prospects of getting to that power with "lemon-aid"?

Paul

At 01:16 AM 6/12/04 +0200, Crispin Pemberton-Pigott wrote:
>Dear Stovers Working by Night
>
>I have become bored waiting for the battery to run down and suspicious
>that the light was running on the dry cell battery even though it
>doesn't have enough voltage to turn it on. So I brought a multimeter
>from work to see how the system was performing.
>
>As he helpers at work had been using the meter and left it turned on the
>9 volt battery was dead so I first have to locate a 9 volt power suppy
>in the junk room, otherwise known as my study. Wiring this into the
>multimeter was accomplished with a Swiss Army knife and I was in action.
>
>There were several remarkable things I discovered about the Lemon Juice
>battery made in an ice cube tray.
>
>The first was the enormous difference in voltage produced by he
>different cells - a factor of 12:1 is some cases. It was clear before
>long that the difference was the presence or otherwise of the fruit
>pulp. Fruit pulp is apparently a very good insulator. When I took the
>lemon pulp out of the cells the current went up by a factor of 5 or 7.
>So there is a good piece of information - use juice!
>
>The next surprise was that the voltage started FAR higher than it was
>when it was running. This is not so surprising as it is a chemical
>reaction that is being captured, but still, the no-load voltage went up
>to 1560 mV while under load it dropped to 160 mV for 6 cells.
>
>The current was surprisingly low. When initially connect there was a
>surge of current of about 450 microamps which then settled at 140
>microamps as the voltage dropped. That was the current lighting up the
>LED.
>
>I made two cells using bronze and aluminum by taking a heat sink out of
>the ill-fated Toshiba and breaking off a rectangular piece and forming
>it to the bottom of the ice cube cell. On top of this I put a small
>piece of cloth cut from one of my older shirts and then put in a coil of
>bronze wire which I de-coiled from an old guitar string (the E string if
>you are interested).
>
>These cells put out a remarkable 560 mV each under no load.
>
>Conclusion:
>
>The lemon cell boosting a dry cell battery works by building up a much
>higher voltage than it can sustain when connected to a load - rather
>like a chemical capacitor. This initial burst of voltage and current
>can overcome the forward breakdown voltage of the LED and get the
>current to flow. Once it is flowing, the current from the dry cell
>battery was keeping the system going, almost entirely. The voltage
>supplied by the lemon juice cells was reduced to a trickle, but was
>still required.
>
>Without the lemons it LED would not start, but it is possible that it
>would continue without it, so when I tried shunting it out The light
>went out, i.e. the LED could not keep going on 1.45 volts from the
>battery.
>
>The power generated by the lemons was 10 to 20 milliwatts on a
>continuous basis, but without its voltage kick, the LED would not start
>and run. Most interesting.
>
>Regards
>Crispin

From jeff.forssell at CFL.SE Mon Jun 14 03:28:28 2004
From: jeff.forssell at CFL.SE (Jeff Forssell)
Date: Tue Aug 10 18:31:15 2004
Subject: plancha vs open fire
Message-ID: <MON.14.JUN.2004.092828.0200.JEFF.FORSSELL@CFL.SE>

Swedish woodstoves had wavy parallell finns under the round "potholes"
cast iron covers (with concentric about 1 cm wide loose rings for
fitting different sized pots (and waffle griddles, (clothes-)iron
heaters.). The cast irom "plancha" usually had 2-4 of these and you
could change their temp by twisting the finns so they were parallell or
across the hot gas flow. The finns could foul up with soot quite rapidly
with poor combustion.

> a disk with a special bottom such as
>
> fins to redirect the heat flow to the sides,

From takeda at SONIC.NET Mon Jun 14 06:14:07 2004
From: takeda at SONIC.NET (Matthew Takeda)
Date: Tue Aug 10 18:31:15 2004
Subject: Absortion chillers using our heat
Message-ID: <MON.14.JUN.2004.031407.0700.TAKEDA@SONIC.NET>

Art Krenzel wrote:

>See www.rvmobile.com

Similar information at:

<http://www.gasrefrigeration.net/how_they_work.htm>

I had this link in my bookmarks because they're in the next town from me.

FWIW, I've had the US version of this
<http://www.dometic.com/node1123.asp?Model=RC%203000%20PowerFridge> running
almost continuously on either electricity or propane for about two years
now. When it's not traveling with us, it sits in the house, plugged into
the mains power. Aside from needing to be defrosted occasionally, it's
required no maintenance whatsoever.

Matthew Takeda
the JOAT
From crispin at NEWDAWN.SZ Mon Jun 14 17:31:14 2004
From: crispin at NEWDAWN.SZ (Crispin Pemberton-Pigott)
Date: Tue Aug 10 18:31:15 2004
Subject: plancha vs open fire
Message-ID: <MON.14.JUN.2004.233114.0200.>

Dear Paul

>> Where one wants extra heat on the disc part of the time and normal
>> heat the rest, two or more thin(er) discs can be placed into the
hole.
>> They conduct heat less efficiently from one to another than a solid
>> disc.

>Could we get a desired result (of some type yet to be
>defined) if the replacement disks were made of different
>materials.

Yes

I am thinking of a copper disk for quicker heat transfer.

That is probably the best available material - as opposed to materials
that are unavailable.

>an aluminum disk (??)

No chance - melts at too low a temperature and gets quite soft before
that. It would deform before it melted.

>a ceramic disk

I am looking for a highly conductive ceramic material. Remember the
discussion we had about an Enjera cooking plate that would conduct heat
better than the clay plate now used?

>a disk with a special shape (such as concave) to
>match a particular pot

Good suggestion! Perhaps an aluminum plate formed to suit the pot and
the right diameter to suit the stove, at a place not directly over the
fire, would transfer the most heat with available materials to a
non-flat surface. Somehow I doubt that it would be more efficient than
a well shaped heat shield with the hot gasses passing through, with the
possible exception of a shaped plate with fins on the bottom (high
surface gas contact area). Such a steel plate could be made quite
easily by welding ribs on the bottom of a standard flat plate. How
about trying that? The welds should be continuous to maximize heat
movement to the upper surface. It wil probably have to be flattened
after welding.

>an insert (not even a disk, but an insertable chamber
>that hangs down into the path of the heat) such as
>a "well" for water to be quickly brought to a boil)

I did this with an updraft coal stove and it has the great advantage of
keeping the pots clean which raising heat transfer efficiency by about
2/3 (from 15% to 25%). I likd it a lot and even draw some tooling for
producing the shapes required quickly.

>a disk with a special bottom such as fins to redirect
>the heat flow to the sides,

Or simple to collect heat preferentially to the round plate upon which
the pot sits.

>or copper tubes/coils that connect to a gravity-fed hot water heater.

Waste heat collection - OK if you are not too efficiet about it. We
have an interesting test burn today in JHB during which it because clear
that maximizing stack heat collection interfered with stove lighting!

>...the size of the hole (and the disks) could be larger
>so that more types of disks could be used with the
>same hole.

Another possiblity is to make heat shields with flared (conical) bottoms
to collect heat from a larger surface than the pot footprint and
channel/contain the air nest to the sides.

I ma a bit worried about people trying to cook a pancake-type food on
the top of the plate without any pan, and then balancing that desire
with a need to collect heat into concentrated area where a pot site.
The best looking and cheapest way to have both is a smooth surface (no
holes) and an inverted cone into which the pot sits (as described
above).

Regards on a chilly night in Ezulwini
Crispin

From Gavin at AA3GENERGI.FORCE9.CO.UK Mon Jun 14 18:25:53 2004
From: Gavin at AA3GENERGI.FORCE9.CO.UK (Gavin Gulliver-Goodall)
Date: Tue Aug 10 18:31:15 2004
Subject: Lemon Light
In-Reply-To: <4.3.1.2.20040613154438.020b3250@mail.ilstu.edu>
Message-ID: <MON.14.JUN.2004.232553.0100.GAVIN@AA3GENERGI.FORCE9.CO.UK>

I have been watching this one with interest.

There are numerous very small , low power fans available - like the one
cooling my laptop, at very low prices - if you buy enough of them, which may
be enough to control the fire in a stove,

I guess ther are many acid fruit to make batteries from.

In a way we are going back to the experiments of Voltaire & co. perhaps
referring to their work would be useful as they had limited raw materials
and manufacturing resources and so their early developments might be readily
transferable to Crispins experiment.

Keep the love-light shinin'

Every clouds got a sil-ver linein'

Gavin

-----Original Message-----
From: The Stoves Discussion List [mailto:STOVES@LISTSERV.REPP.ORG]On Behalf
Of Paul S. Anderson
Sent: Sunday, June 13, 2004 21:57
To: STOVES@LISTSERV.REPP.ORG
Subject: Re: [STOVES] Lemon Light

Crispin,

Very interesting. Now help me understand where this is taking us. Can we
get meaningful power (micro-power) from the "lemon light" concept?

Is it a question of size of the container of juice and area size of the two
metal "plates" in each power cell?

Paul

From phoenix98604 at EARTHLINK.NET Mon Jun 14 18:27:25 2004
From: phoenix98604 at EARTHLINK.NET (Art Krenzel)
Date: Tue Aug 10 18:31:15 2004
Subject: Lemon Light
Message-ID: <MON.14.JUN.2004.152725.0700.PHOENIX98604@EARTHLINK.NET>

Paul,

The battery/charger sizing problem becomes smaller when you consider the
duty cycle of the fan and the stove. The fan/battery might be used 6 - 8
hrs per day whereas the "juice powered" charger could operate 24 hours per
day recharging it. The battery would act as a capacitor in the fan/charger
circuit.

Go Science Fair!!

Art Krenzel
----- Original Message -----
From: "Paul S. Anderson" <psanders@ILSTU.EDU>
To: <STOVES@LISTSERV.REPP.ORG>
Sent: Sunday, June 13, 2004 1:56 PM
Subject: Re: [STOVES] Lemon Light

> Crispin,
>
> Very interesting. Now help me understand where this is taking us. Can we
> get meaningful power (micro-power) from the "lemon light" concept?
>
> You wrote:
> >The current was surprisingly low. When initially connect there was a
> >surge of current of about 450 microamps which then settled at 140
> >microamps as the voltage dropped. That was the current lighting up the
> >LED.
>
> If 140 microamps is sufficient (plus presence of a small battery that
seems
> to be needed but not actually being consumed by the LED), THAT seems to be
> significant considering the "ice cube tray plus wire" of this early
testing.
>
> Is it a question of size of the container of juice and area size of the
two
> metal "plates" in each power cell?
>
> And what amount of power is needed? 1000 microamps to get one amp,
> right? What can we do with 1 amp? or with 1/10th amp? I am after
the
> power to run a very small motor to drive a fan like in Tom's Woodgas
> Campstove. What are the prospects of getting to that power with
"lemon-aid"?
>
> Paul
>
> At 01:16 AM 6/12/04 +0200, Crispin Pemberton-Pigott wrote:
> >Dear Stovers Working by Night
> >
> >I have become bored waiting for the battery to run down and suspicious
> >that the light was running on the dry cell battery even though it
> >doesn't have enough voltage to turn it on. So I brought a multimeter
> >from work to see how the system was performing.
> >
> >As he helpers at work had been using the meter and left it turned on the
> >9 volt battery was dead so I first have to locate a 9 volt power suppy
> >in the junk room, otherwise known as my study. Wiring this into the
> >multimeter was accomplished with a Swiss Army knife and I was in action.
> >
> >There were several remarkable things I discovered about the Lemon Juice
> >battery made in an ice cube tray.
> >
> >The first was the enormous difference in voltage produced by he
> >different cells - a factor of 12:1 is some cases. It was clear before
> >long that the difference was the presence or otherwise of the fruit
> >pulp. Fruit pulp is apparently a very good insulator. When I took the
> >lemon pulp out of the cells the current went up by a factor of 5 or 7.
> >So there is a good piece of information - use juice!
> >
> >The next surprise was that the voltage started FAR higher than it was
> >when it was running. This is not so surprising as it is a chemical
> >reaction that is being captured, but still, the no-load voltage went up
> >to 1560 mV while under load it dropped to 160 mV for 6 cells.
> >
> >The current was surprisingly low. When initially connect there was a
> >surge of current of about 450 microamps which then settled at 140
> >microamps as the voltage dropped. That was the current lighting up the
> >LED.
> >
> >I made two cells using bronze and aluminum by taking a heat sink out of
> >the ill-fated Toshiba and breaking off a rectangular piece and forming
> >it to the bottom of the ice cube cell. On top of this I put a small
> >piece of cloth cut from one of my older shirts and then put in a coil of
> >bronze wire which I de-coiled from an old guitar string (the E string if
> >you are interested).
> >
> >These cells put out a remarkable 560 mV each under no load.
> >
> >Conclusion:
> >
> >The lemon cell boosting a dry cell battery works by building up a much
> >higher voltage than it can sustain when connected to a load - rather
> >like a chemical capacitor. This initial burst of voltage and current
> >can overcome the forward breakdown voltage of the LED and get the
> >current to flow. Once it is flowing, the current from the dry cell
> >battery was keeping the system going, almost entirely. The voltage
> >supplied by the lemon juice cells was reduced to a trickle, but was
> >still required.
> >
> >Without the lemons it LED would not start, but it is possible that it
> >would continue without it, so when I tried shunting it out The light
> >went out, i.e. the LED could not keep going on 1.45 volts from the
> >battery.
> >
> >The power generated by the lemons was 10 to 20 milliwatts on a
> >continuous basis, but without its voltage kick, the LED would not start
> >and run. Most interesting.
> >
> >Regards
> >Crispin
>
> Paul S. Anderson, Ph.D.
> Dept of Geography - Geology (Box 4400), Illinois State University
> Normal, IL 61790-4400 Voice: 309-438-7360; FAX: 309-438-5310
> E-mail: psanders@ilstu.edu - Internet items: www.ilstu.edu/~psanders
> NOTE: Retired from teaching. Active in Stoves development.
> For fastest contact, please call home phone: 309-452-7072
>

From list at SYLVA.ICUKLIVE.CO.UK Mon Jun 14 19:48:16 2004
From: list at SYLVA.ICUKLIVE.CO.UK (Andrew Heggie)
Date: Tue Aug 10 18:31:15 2004
Subject: Lemon Light
In-Reply-To: <MABBJLGAAFJBOBCKKPMGAENKDKAA.Gavin@aa3genergi.force9.co.uk>
Message-ID: <TUE.15.JUN.2004.004816.0100.>

On Mon, 14 Jun 2004 23:25:53 +0100, Gavin Gulliver-Goodall wrote:

>
>There are numerous very small , low power fans available - like the one
>cooling my laptop, at very low prices - if you buy enough of them, which may
>be enough to control the fire in a stove,

I was interested in how these little electronically commutator fans
worked, in theory they should have a good life, though I have had some
fail in my limited use of PCs since 1995.
>
>I guess ther are many acid fruit to make batteries from.

Are these cells all primary? With a high internal resistance and
mismatched low impedance load most of the energy will be dissipated in
the cell as heat, so they may be restricted to loads like the led.
Still with polarisation effects I imagine they have limited potential.

>Keep the love-light shinin'
>
>Every clouds got a sil-ver linein'

But I won't make a fuss
Though it's obvious

(lyrics from a british pop song from the hippy era)

AJH

From kchisholm at CA.INTER.NET Tue Jun 15 01:09:17 2004
From: kchisholm at CA.INTER.NET (Kevin Chisholm)
Date: Tue Aug 10 18:31:16 2004
Subject: plancha vs open fire
Message-ID: <TUE.15.JUN.2004.020917.0300.KCHISHOLM@CA.INTER.NET>

Dear Jeff
----- Original Message -----
From: "Jeff Forssell" <jeff.forssell@CFL.SE>
To: <STOVES@LISTSERV.REPP.ORG>
Sent: Monday, June 14, 2004 4:28 AM
Subject: Re: [STOVES] plancha vs open fire

> Swedish woodstoves had wavy parallell finns under the round "potholes"
> cast iron covers (with concentric about 1 cm wide loose rings for
> fitting different sized pots (and waffle griddles, (clothes-)iron
> heaters.). The cast irom "plancha" usually had 2-4 of these and you
> could change their temp by twisting the finns so they were parallell or
> across the hot gas flow. The finns could foul up with soot quite rapidly
> with poor combustion.

What about if you used Swedes, rather than Finns? Swedes don't foul things
up rapidly, do they? :-)

Seriously, the sooting is the proof of "cold and incomplete combustion."
There is a serious problem with the design of a stove that soots up.

Fix the "cold combustion problem" and the sooting will not be a problem.

Kindest regards,

Kevin
>
> > a disk with a special bottom such as
> >
> > fins to redirect the heat flow to the sides,

From pverhaart at IPRIMUS.COM.AU Tue Jun 15 02:23:19 2004
From: pverhaart at IPRIMUS.COM.AU (Peter Verhaart)
Date: Tue Aug 10 18:31:16 2004
Subject: Lemon Light
In-Reply-To: <4.3.1.2.20040613154438.020b3250@mail.ilstu.edu>
Message-ID: <TUE.15.JUN.2004.162319.1000.PVERHAART@IPRIMUS.COM.AU>

At 15:56 13/06/2004 -0500, you wrote:
>Crispin,
>
>And what amount of power is needed? 1000 microamps to get one amp,
>right? What can we do with 1 amp? or with 1/10th amp? I am after the
>power to run a very small motor to drive a fan like in Tom's Woodgas
>Campstove. What are the prospects of getting to that power with "lemon-aid"?

You are a factor 1000 off. Not an uncommon thing for Americans calling a
milliard a billion.
Micro means 10 ^-6.

Cheers,

Peter Verhaart

From crispin at NEWDAWN.SZ Tue Jun 15 07:46:16 2004
From: crispin at NEWDAWN.SZ (Crispin)
Date: Tue Aug 10 18:31:16 2004
Subject: Lemon Light
Message-ID: <TUE.15.JUN.2004.134616.0200.CRISPIN@NEWDAWN.SZ>

Dear Paul

How about using a large capacitor instead of a battery? It would cost less
and could withstand millions of charges.

Regards
Crispin

From larencorie at AXILAR.NET Tue Jun 15 09:03:12 2004
From: larencorie at AXILAR.NET (LarenCorie)
Date: Tue Aug 10 18:31:16 2004
Subject: Lemon Light
Message-ID: <TUE.15.JUN.2004.090312.0400.LARENCORIE@AXILAR.NET>

Gavin Gulliver-Goodall <Gavin@AA3GENERGI.FORCE9.CO.UK>wrote;

> I guess ther are many acid fruit to make batteries from.

There are also batteries made from potatoes.
Another approach that seems interesting, is
a similar battery that uses the ground.

I found this:

"Yesterday I pushed a 6" dia HVAC duct section about 12" long
(available at any hardware store) into the ground, then pushed
a 3/4" copper pipe (like you would use for house plumbing)
into the middle of that. It created 0.95 V. I made another one,
and in series they generated 1.35 volts and 0.3 MilliAmps. I
tried hooking up a flashlight bulb to it but it did not light. A
typical 1.5 AA battery creates 70 MilliAmps. A coffee can
filled with mud and the copper tube generated 0.3 volts. I
didn't measure the amperage. I'd like to try to make a
StubbleField Earth battery. Lyle "

http://en.wikipedia.org/wiki/Earth_battery

http://tinyurl.com/2hnsl

http://www.amasci.com/miscon/miscon4.html#lemon

http://www.icehouse.net/john1/stublefield1.html

http://geoffegel.tripod.com/earth.htm

-Laren Corie-

From kchisholm at CA.INTER.NET Tue Jun 15 14:38:14 2004
From: kchisholm at CA.INTER.NET (Kevin Chisholm)
Date: Tue Aug 10 18:31:16 2004
Subject: Lemon Light
Message-ID: <TUE.15.JUN.2004.153814.0300.KCHISHOLM@CA.INTER.NET>

Dear All

With all due respect, the boat is being missed. Lemon juice is NOT the
battery. Earth is NOT the battery. It is the iron, copper, zinc, aluminium,
etc that is "the battery", or the basic source of energy.

These batteries will work very well until all their metal is converted to
oxides, or other "lower energy state products of reaction."

You can get as much current as you want, simply by enabling an adequately
large area of metal to be available for corrosion at any one time. You can
get as much voltage as you want simply by connecting an adequate number of
such cells in series to form a "battery."

Best wishes,

Kevin Chisholm

----- Original Message -----
From: "LarenCorie" <larencorie@AXILAR.NET>
To: <STOVES@LISTSERV.REPP.ORG>
Sent: Tuesday, June 15, 2004 10:03 AM
Subject: Re: [STOVES] Lemon Light

> Gavin Gulliver-Goodall <Gavin@AA3GENERGI.FORCE9.CO.UK>wrote;
>
> > I guess ther are many acid fruit to make batteries from.
>
> There are also batteries made from potatoes.
> Another approach that seems interesting, is
> a similar battery that uses the ground.
>
> I found this:
>
> "Yesterday I pushed a 6" dia HVAC duct section about 12" long
> (available at any hardware store) into the ground, then pushed
> a 3/4" copper pipe (like you would use for house plumbing)
> into the middle of that. It created 0.95 V. I made another one,
> and in series they generated 1.35 volts and 0.3 MilliAmps. I
> tried hooking up a flashlight bulb to it but it did not light. A
> typical 1.5 AA battery creates 70 MilliAmps. A coffee can
> filled with mud and the copper tube generated 0.3 volts. I
> didn't measure the amperage. I'd like to try to make a
> StubbleField Earth battery. Lyle "
>
> http://en.wikipedia.org/wiki/Earth_battery
>
> http://tinyurl.com/2hnsl
>
> http://www.amasci.com/miscon/miscon4.html#lemon
>
> http://www.icehouse.net/john1/stublefield1.html
>
> http://geoffegel.tripod.com/earth.htm
>
> -Laren Corie-

From crispin at NEWDAWN.SZ Tue Jun 15 16:42:57 2004
From: crispin at NEWDAWN.SZ (Crispin Pemberton-Pigott)
Date: Tue Aug 10 18:31:16 2004
Subject: Lemon Light
Message-ID: <TUE.15.JUN.2004.224257.0200.>

Dear Stove Lighters

RE Andrew's questions:

>Are these cells all primary? With a high internal
>resistance and mismatched low impedance
>load most of the energy will be dissipated in
>the cell as heat, so they may be restricted to
>loads like the led.

I have just returned from an interesting apple crumble with Rooibos tea
with Reginal Barrow which went down well while discussing in some detail
the meaning of 'internal resistance' with reference to chemical
batteries. We were strong on theory but weak on conclusions.

Essentially we can't see a practical difference between an internal
resistance in a battery and an inability of the acid (in our lemon case)
to transport electrons off one plate onto another. If one agrees that
the 'current' is the movement of these electrons, and that the ability
of the chemicals to accomplish this is variable according to agitation,
concentration and temperature, then one can impute a 'chemical
resistance' as a way of describing the overall behaviour, but to assign
the name 'internal resistance' to this inadequacy may be convenient
rather than technically accurate. So we defer to those who study these
things. Heat is generated by the chemical action, but to describe this
_as_ resistance without it _being_ resistance in regular regular sense
causes some logical problems.

I brought another sensitive meter home from work so that I can measure
current and voltage simultaneously. It is apparently a freebie given to
me by E&E the TSI agent in Canada who tossed it into the box as a
'Sorry" for taking 2 months to send me my CA-6203 which has _finally_
arrived. It is more complicated than I remember.

I also now proudly (no kidding) possess 4 (count them!) HE-LED's brought
in by Tycho Schelart from Eindhoven (hello Dr. Prasad). I have 4
different colours including a 20 milliamp white one with I think 10
times the light output of the more ordinary kind. They are rated at 3.5
volts max and 20 mA so the efficiency is pretty high as that is a very
low maximum current.

It is unlikely that I will get to make a multi-cell lemon light battery
with 3.5 volts during the course of the week but it is probably possible
in a standard ice cube tray. I promise to get around to it now that my
kitchen table is even better equipped (good job my wife is in Ontario -
it is a mess).

The LED has been running weak for a week so I will give up on that. Let
us just agree that is goes on for ages. I do not observe any visible
deterioration of the metals.

>>Keep the love-light shinin'
>>Every clouds got a sil-ver linein'

>But I won't make a fuss
>Though it's obvious

There once was a stover from Bristol
Who started his fires with a pistol
Though some expressed fears
'Bout the pain in their ears,
The feeling he got was quite visceral.

(Just one from a collection of unwritten poems)

Regards
Crispin

From dbneeley at YAHOO.COM Tue Jun 15 18:46:56 2004
From: dbneeley at YAHOO.COM (David Neeley)
Date: Tue Aug 10 18:31:16 2004
Subject: A small question on the "Rocket Stove"
In-Reply-To: <200406150400.i5F401714559@ns1.repp.org>
Message-ID: <TUE.15.JUN.2004.154656.0700.>

As I feel I am still very much a "newbie", perhaps this has
been addressed before...but...

I am looking with great interest at the "Pyromid" stove
that is so efficient and I wondered...Could the "Rocket"
stove design be amended to have a reflective chamber below
and to the sides of the point of burn to help concentrate
the heat?

I've noticed that many of these are being cast in several
pieces and then assembled; would it thus be worthwhile to
make such a shape variation--perhaps to be lined with foil
of some sort that, when dirty, could be cheaply replaced?

Secondly, also from the same speculation, could the
fuel/air intake be made more horizontally oval so that the
individual sticks to be burned could be spaced to take
advantage of the sort of heat intensification that takes
place in the Pyromid design?

Sorry if this has been tried, or if it does not make sense
because of my present level of ignorance!

Regards to all,

David

__________________________________
Do you Yahoo!?
Yahoo! Mail is new and improved - Check it out!
http://promotions.yahoo.com/new_mail

From list at SYLVA.ICUKLIVE.CO.UK Tue Jun 15 19:04:42 2004
From: list at SYLVA.ICUKLIVE.CO.UK (Andrew Heggie)
Date: Tue Aug 10 18:31:16 2004
Subject: Lemon Light
In-Reply-To: <00b001c45308$fb70e460$da9a0a40@kevin>
Message-ID: <WED.16.JUN.2004.000442.0100.>

On Tue, 15 Jun 2004 15:38:14 -0300, Kevin Chisholm wrote:

>Dear All
>
>With all due respect, the boat is being missed. Lemon juice is NOT the
>battery. Earth is NOT the battery. It is the iron, copper, zinc, aluminium,
>etc that is "the battery", or the basic source of energy.

This is true, hence my earlier posts, but it does not necessarily make
the concept unsupportable, because in the absence of using these scrap
materials in this manner what will happen to them? Will they not
simply return to their lower energy state ( be it oxide, sulphate or
whatever) without the benefit of giving light? Mins overall I agree,
using primary cells has little future in this circumstance, coupling a
rechargeable battery to a non scheduled form of renewable energy seems
a better prospect.

http://science.howstuffworks.com/battery.htm

AJH

From sushim45 at HOTMAIL.COM Wed Jun 16 00:28:50 2004
From: sushim45 at HOTMAIL.COM (Sushim Amatya)
Date: Tue Aug 10 18:31:16 2004
Subject: Metal Stoves for Hill hill regions of Nepal
Message-ID: <WED.16.JUN.2004.002850.0400.SUSHIM45@HOTMAIL.COM>

One of the priority for United Nations Millennium Development Goal is
providing clean energy for the developing communities. With regard to the
local context, this clean energy can be provided to the people of Nepal are
provided with clean sources of fuel. However, the privilege of having an
access to clean energy is limited only to the urban areas. Most of the
people of Nepal are forced to be satisfied using firewood as fuel. Not
surprisingly, fuel wood constitutes of about 74% of total energy demand
thus putting a huge pressure not only on the reducing forests but also on
the commitment of Nepal to reduce GHG emissions and the government's and
NGOs, INGOs initiative to reduce the deaths due to ARI (Acute Respiratory
Infection). Few researches are directed onto finding out the actual
scenario on the extent of the effect of cook stoves in health. The
researches done outside Nepal have proved the case whereas; it is corollary
that the same case exists in Nepal too. In this regard, promotion of
Improved Cook Stoves by the government has been commendable. However, the
model so being promoted is restricted to a very old design on which
unfortunately no further research has been conducted. Nonetheless, the
program has been going on to meet its objectives.

Promotion and Dissemination of Improved Cook Stoves in the hilly region has
however a different approach. Room and Space Heating coupled with the
ability of the cook stove for reduced consumption of firewood demands cook
stoves different than those which are disseminated in mild climates in the
terai region. The improved cook stoves for hilly cold areas are made of
metal while those in the hot terai regions are made from mud and brick.
However, the dissemination of metal stoves faces a huge problem. This
problem arises from the high cost of transportation that is associated with
transporting of already prefabricated and manufactured steel stoves from
the manufacturers in urban areas to the far away rural places high up in
the hills. This high cost inevitably leads to the price hike of cook
stoves, which puts an unbearable financial pressure on the poor economy of
people in high hilly areas. This has led to the people stick to the
traditional cook stoves and doing so unwillingly bear the consequences of
cancerous indoor air pollution.

If the improved metal cook stoves are so designed so that the bulky stoves
need not be carried one by one and instead are knocked down into flat
sheets that can be assembled using minimal welding (or no welding at all)
technique or folding technique in the regions where they are to be
disseminated, they might provide a drastic reduction in the cost of cook
stoves thus leading to an effective and wide dissemination of improved
metal cook stoves. Furthermore, mass manufacturing of such models of stoves
along with increased versatility, will reduce the cost of the cook stoves
in multiple proportion also providing creation of jobs in the areas. This
will prove to be a good boost to the government and foreign donors
initiative to provide effective clean energy to the people of Nepal.

In this regard, Sustainable Technology ? Adaptive Research and
Implementation Center, Nepal (STARIC/N) with its aim to effectively utilize
the huge untapped engineering resources into the development of Nepal, is
conducting series of projects relating to research and promotion of
cookstoves in collaboration with foreign partners.

From crispin at NEWDAWN.SZ Wed Jun 16 04:12:29 2004
From: crispin at NEWDAWN.SZ (Crispin Pemberton-Pigott)
Date: Tue Aug 10 18:31:16 2004
Subject: Lemon Light
Message-ID: <WED.16.JUN.2004.101229.0200.CRISPIN@NEWDAWN.SZ>

Dear Stovers with Light in Mind

Thanks AJ.

http://science.howstuffworks.com/framed.htm?parent=battery.htm&url=http://members.aol.com/dswart/index.html

will take you to a whole website devoted to running things on lemons
including a Radio Shack LED running on two (count them!) lemons.

Kevin:
>With all due respect, the boat is being missed. Lemon juice is NOT the
>battery.

No...in that case above the lemon is!

Regards
Crispin

From list at SYLVA.ICUKLIVE.CO.UK Wed Jun 16 04:24:09 2004
From: list at SYLVA.ICUKLIVE.CO.UK (Andrew Heggie)
Date: Tue Aug 10 18:31:16 2004
Subject: Metal Stoves for Hill hill regions of Nepal
In-Reply-To: <LISTSERV%2004061600285028@LISTSERV.REPP.ORG>
Message-ID: <WED.16.JUN.2004.092409.0100.>

On Wed, 16 Jun 2004 00:28:50 -0400, Sushim Amatya wrote:

>If the improved metal cook stoves are so designed so that the bulky stoves
>need not be carried one by one and instead are knocked down into flat
>sheets that can be assembled using minimal welding (or no welding at all)
>technique or folding technique in the regions where they are to be
>disseminated, they might provide a drastic reduction in the cost of cook
>stoves thus leading to an effective and wide dissemination of improved
>metal cook stoves.

Welcome to the stoves discussion Sushim. We are still waiting for an
idea of what is affordable in your region and what practical means of
measuring stove flue gas and air quality measurements are available to
workers there.

I hope Crispin can offer some advice on the possibility for a flat
pack tincanium (a word coined by a list member to describe use of used
tinplated steel containers) stoves. The alternative is to consider
nesting bucket shaped stoves.

> Furthermore, mass manufacturing of such models of stoves
>along with increased versatility, will reduce the cost of the cook stoves
>in multiple proportion also providing creation of jobs in the areas. This
>will prove to be a good boost to the government and foreign donors
>initiative to provide effective clean energy to the people of Nepal.

Again, from A.D. Karve in India, we have had discussion that mass
production in high capital intensive factories may not benefit a local
region and, despite lower economies of scale, a simple local workshop
may be of more local benefit.
>
>In this regard, Sustainable Technology ? Adaptive Research and
>Implementation Center, Nepal (STARIC/N) with its aim to effectively utilize
>the huge untapped engineering resources into the development of Nepal, is
>conducting series of projects relating to research and promotion of
>cookstoves in collaboration with foreign partners.

Is this the organisation you work with?

AJH

From ajh at SYLVA.ICUKLIVE.CO.UK Wed Jun 16 04:54:49 2004
From: ajh at SYLVA.ICUKLIVE.CO.UK (AJH)
Date: Tue Aug 10 18:31:16 2004
Subject: Lemon Light
In-Reply-To: <003801c45379$b1bcb8a0$cb83fea9@md>
Message-ID: <WED.16.JUN.2004.095449.0100.AJH@SYLVA.ICUKLIVE.CO.UK>

On Wed, 16 Jun 2004 10:12:29 +0200, Crispin Pemberton-Pigott wrote:

>Dear Stovers with Light in Mind
>
>Thanks AJ.
>
>http://science.howstuffworks.com/framed.htm?parent=battery.htm&url=http://members.aol.com/dswart/index.html
>
>will take you to a whole website devoted to running things on lemons
>including a Radio Shack LED running on two (count them!) lemons.
>
>Kevin:
>>With all due respect, the boat is being missed. Lemon juice is NOT the
>>battery.
>
>No...in that case above the lemon is!

Crispin in the link you posted the zinc anode is still being oxidised
whilst the copper is not.

I believe there are zinc air cells that can be recharged though I am
not sure what limits the number of charging cycles, contamination or
build up of un wanted chemical structures seems to limit most of the
electro chemical cells, I believe this is why fuel cells require such
pure hydrogen to run them, otherwise there life is too short.

I read of a continuous flow redox cell, which had the potential to be
a long term energy store with the chemical regenerated outwith the
cell but cannot remember details.

As with any form of energy conversion there is no free lunch when it
comes to batteries. The energy has to come from somewhere, I am still
unsure of how the potato cell generates electricity, is it from
oxidising the starch?

The only direct conversion of biomass to electricity seemed to be the
"fused carbonate" cell, from memory, though I have not seen it
discussed recently.

Now with the declared preference for NimH batteries and the resource
in the west of these from obsolete mobile phones (I believe Tom Miles
was involve in a gasification project to utilise the plastics in
discarded mobile phones), 30 million people use them in UK and I
expect the average use is <3 years, how much utility is left in these
batteries for re use storing power for these LEDs?

Most cell phones seem to use lithium ion batteries now, will these be
an acceptable battery for this use?

Is recharging at a centralised point acceptable? Schools were
mentioned as recharging points. In UK in the 1920s the local garage
would have a genset and recharge "accumulators" for home use. I think
they were used for light but IRRC they were used in radios too, with
packs of dry (non rechargeable) cells providing the high voltage
necessary to run the tubes.

AJH

From Kanchan at KU.EDU.NP Wed Jun 16 17:33:54 2004
From: Kanchan at KU.EDU.NP (Kanchan Rai)
Date: Tue Aug 10 18:31:16 2004
Subject: which emission is more important measuring
Message-ID: <THU.17.JUN.2004.031854.0545.KANCHAN@KU.EDU.NP>

> Tami wrote:

>
> At this point there is NOT an easy way to measure particulate matter.
> I have looked, a lot. But maybe you could tell us what is 'affordable'
> for a university like yours.
>
> Kirk Smith is working on a particle measurement package, which will be
> available sometime. And we are trying to get a relatively inexpensive
> setup installed at Aprovecho, but I think it is still expensive by
> Kathmandu standards. My hope is that by iterating with testing places
> that are close by us (like Apro) we can work out the bugs of what we
> have proposed. Then we eventually come up with something workable for
> universities who are less well funded overseas.
>
> We are also setting up one of these university labs of skeptical value
> (wink, AJH) and the idea is to compare the results from fancy
> equipment with cheaper equipment to determine just how cheap we can
> go, and still be useful to stovers like you.
>

Sorry for the late response, I have been busy for last 2 weeks. still
plenty of emails of stove discussion I didn't opened.

Thanks for taking interest. My university is very young, research
is very new here and we are very much limited with equipements.
At least, I am hoping to get a gas analyser for my stove research soon
after 2 years of waiting. At the moment I can't afford the methods in
the way you are asking for my affodability. But I like to know about
Kirk Smith particle measurement methods and the costs if possible.

best regards,
kanchan rai
RDC unit
research assistant
kathmandu university

From tombreed at COMCAST.NET Wed Jun 16 08:17:20 2004
From: tombreed at COMCAST.NET (TBReed)
Date: Tue Aug 10 18:31:16 2004
Subject: [GASL] Ecalene(tm) from syngas
Message-ID: <WED.16.JUN.2004.061720.0600.TOMBREED@COMCAST.NET>

Dear Arnt and All:

I worked with Gene Jackson, president of Power Energy for 5 years in the
1985-90 period and we have kept in touch. We had lunch a few months ago.
He claims to have a new improved catalyst for conversion of syngas to mixed
higher alcohols rather than the methanol has been commercial for 80 years.

I wish Power Energy and Ecalene the very best. But don't consider it a done
deal.

The production of clean synthesis gas (CO + H2) by any means is technically
difficult, but necessary to make ammonia, methanol, FT diesel ... and
ECALENE (mixed alcohols).

The catalytic conversion of syngas to any of these is a major technical and
economic job for chem engineers and capitalists.

Meanwhile the rest of us can easily make producer gas (CO + H2 + 50% N2) for
many useful applications.

~~~~~~~~~~~
The BEF has recently received a subcontract for converting waste to WoodGas
for army field kitchen cooking. As a spinoff I'm sure it will work for the
rest of us.... A principal part of the problem will be to get the waste
into usable fuel form. Any suggestions?

TOM REED BEF GASWORKS BEF STOVEWORKS

----- Original Message -----
From: "Arnt Karlsen" <arnt@C2I.NET>
To: <GASIFICATION@LISTSERV.REPP.ORG>
Sent: Tuesday, June 15, 2004 7:20 PM
Subject: Re: [GASL] Ecalene(tm) from syngas

> On Mon, 14 Jun 2004 12:49:27 -0400, Matthew wrote in message
> <opr9lfopv26c175d@localhost>:
>
> > Hey guys. I am seriously interested in ethanol from syngas
> > technologies, as I feel it is a more practical transportation fuel
> > than pure hydrogen. Recently, I came across this. Just posting it to
> > see what you think of it.
> >
> > Quote from the web site:
> >
> > "There is no other known catalytic process available in the world that
> > is capable of converting carbonaceous sources into higher mixed
> > alcohols at the conversion rate achieved by the Power Energy System___
> > ."
> >
> > http://www.powerenergy.com/index.html
>
> ..sure, their process works allright, Herrmann G?ring had Luftwaffe
> fly on that stuff too. ;-)
>
> > --
> >
> > Matthew Pottinger
> >
> > Student
> > Environmental Technology Program
> > Durham College
> > Ontario, Canada
> >
> > "Never underestimate people's
> > ability to suppress inconvenient realities."
> >
> > "We could avoid the extinction of the human race,
> > but it just wouldn't be economically feasible."
>
> ..so, why is it not? Show us how you are more worth doing your own
> homework, rather than producing gas, heat and electric power in a
> thermochemical gasifier hooked to a genset and the grid, for that we
> need a baseline; How much do you weigh? ;-)
>
> --
> ..med vennlig hilsen = with Kind Regards from Arnt... ;-)
> ...with a number of polar bear hunters in his ancestry...
> Scenarios always come in sets of three:
> best case, worst case, and just in case.

From hotspringfreak at HOTMAIL.COM Wed Jun 16 15:17:20 2004
From: hotspringfreak at HOTMAIL.COM (Chris Smith)
Date: Tue Aug 10 18:31:16 2004
Subject: Lemon Light
Message-ID: <WED.16.JUN.2004.151720.0400.HOTSPRINGFREAK@HOTMAIL.COM>

Greetings though I have no LED's yet, I can still Google for now!

A methodology for making a 3 potato LED light is presented in at:

http://www.fofweb.com/Onfiles/SEOF/Science_Experiments/5-40.pdf

A demonstration project using 500 lbs (!) of "battery-ified" potatoes is to
run a PA system is shown at:

http://latteier.com/potato/

Beyond it's novelty, what's most interesting to me about the 500 lb. potato
battery is that groups of "UberTuber"-cells are wired in series to get
sufficient voltage and then these smaller battery groupings are further
wired in parallel to increase amperage. I believe this series/parallel
configuration should be sufficient to overcome resistance in lighting a LED
lemon-light.

best,

Chris Smith

From Carefreeland at AOL.COM Thu Jun 17 15:50:35 2004
From: Carefreeland at AOL.COM (Carefreeland@AOL.COM)
Date: Tue Aug 10 18:31:16 2004
Subject: [GASL] Gasification of biosolids
Message-ID: <THU.17.JUN.2004.155035.EDT.>

In a message dated 6/11/04 12:38:25 PM Eastern Daylight Time,
list@SYLVA.ICUKLIVE.CO.UK writes:

DD This is my response to a Gasification topic.

> Right on Matthew, it's still my ambition to earn some money from this
> wood burning before I retire ;-), note the wood burning rather than
> biosolids. It's chopping the trees down that's kept the roof over so
> far. I suspect Dan the carefree bloke is in a similar position, he
> heats greenhouse with wood and wanted to make electricity also, though
> I haven't heard from him for a while.
>
>
DD Dan the Carefree bloke is still here, reading mail from 6/11/04 on
6/17/04. I am working today on the most important part of all of this
experimentation, creating a financial market for all of the free solar, biomass and someday
maybe wind energy I can harness. In this case, today I am building a market
for greenhouse products.
No mon,(ey) no fun, so they say.
DD To explain entrepreneurial spirit, I can compare it in a lot of ways to
exploring those multi-mile long Kentucky caves. It is dark all the time, the map
doesn't always help and there is little help those outside can lend. Often
the only way to eliminate a path is to go there till you can't. Lastly, you
sometimes have to crawl a long time before you can stand up and walk.
DD On the first of July I quietly celebrate surviving 25 years in business.
I am small guy in the competitive big city landscaping business. It's all
about the Journey, not the destination. If I quit every time I thought about
doing it, I would have restarted my business on a daily basis.
DD The best reason to move ahead is because you can and want to. If you don't
want to move ahead, find out why and act accordingly. All else is immaterial
in the long run.

Daniel Dimiduk
Owner :Carefree Landscape Maintenance Company

From adkarve at PN2.VSNL.NET.IN Fri Jun 18 02:27:41 2004
From: adkarve at PN2.VSNL.NET.IN (adkarve)
Date: Tue Aug 10 18:31:16 2004
Subject: Fw: bamboo in the North-east of India
Message-ID: <FRI.18.JUN.2004.115741.0530.ADKARVE@PN2.VSNL.NET.IN>

There were reports about bamboo flowering in the north-eastern parts in India. In that part of India, the locals cultivate land by clearing forests. Such soil has high fertility in the beginning, but later the yield starts declining. Therefore, after about 5 years of cultivation, the land is abandoned and a new piece of land is cleared for cultivation. The land that is no longer under cultivation is invaded by bamboo. Bamboo is a very fast growing plant and it most probably suppresses the growth of other species. As a result, we have in the North-eastern part of India, vast tracts of land covered by bamboo. Bamboo has many uses and it fetches a good price anywhere in India, but since all this bamboo is in one corner of India, transporting it to other parts of India becomes very costly. Now that all of it is flowering, the only thing that can be done with this bamboo is to convert it into charcoal. Charcoal is chemically and biologically inert, so that it can be stored indefinitely without spoiling. As fuel, bamboo charcoal can be compared to high grade coke.Therefore this charcoal can be used over the years as fuel, either for domestic or even for Industrial purposes.
Yours
Dr.A.D.Karve, President,
Appropriate Rural Technology Institute
Pune, India

From adkarve at PN2.VSNL.NET.IN Fri Jun 18 02:30:14 2004
From: adkarve at PN2.VSNL.NET.IN (adkarve)
Date: Tue Aug 10 18:31:16 2004
Subject: Illuminating with LED
Message-ID: <FRI.18.JUN.2004.120014.0530.ADKARVE@PN2.VSNL.NET.IN>

Dear Stovers,
I got this message today, which might be of interest to some in cotext with
lighting with LED.
A.D.Karve
> ----- Original Message -----
> From: Kelvin Orr <newsdatasource@address.com>
> To: <adkarve@pn2.vsnl.net.in>
> Sent: Friday, March 07, 2003 2:08 AM
> Subject: Offer Notice
>
>
> The revolutionary NightStar? magnetic force flashlight transforms simple
> motion into light.
> When gently shaken, a high strength magnet passes smoothly through a wire
> coil efficiently generating electrical energy. A heavy duty capacitor
stores
> the energy and delivers power to a bright white LED - just 30 seconds of
> shaking provides 20 minutes of light!!
>
> Superior to a battery, the capacitor will never corrode, can be re-charged
> several hundred thousand times and will power the LED even under extreme
hot
> and cold temperatures.
>
> Equally impressive, the solid state LED is practically unbreakable and has
a
> rated lifetime of tens of thousands of hours; in total darkness the
> NightStar? illuminates a 12ft diameter area from a distance of 50ft. The
> state of the art components are all contained within a lightweight
> polycarbonate casing, which is waterproof, corrosion proof, and virtually
> indestructible
>
> In Short the best torch in the world, EVER!
>
> Visit us for more information at http://www.nightstartorch.com
>
>
>

From crispin at NEWDAWN.SZ Fri Jun 18 07:43:31 2004
From: crispin at NEWDAWN.SZ (Crispin Pemberton-Pigott)
Date: Tue Aug 10 18:31:16 2004
Subject: bamboo in the North-east of India
Message-ID: <FRI.18.JUN.2004.134331.0200.CRISPIN@NEWDAWN.SZ>

Dear Karve

Is it true that the bamboo flowers about every 150 years? Then it dies,
right? I seem to remember reading this caused a lot of famine in the 19th
century.

Thanks
Crispin

From snkm at BTL.NET Fri Jun 18 08:29:59 2004
From: snkm at BTL.NET (Peter Singfield)
Date: Tue Aug 10 18:31:16 2004
Subject: Simple solution to lighting
Message-ID: <FRI.18.JUN.2004.062959.0600.SNKM@BTL.NET>

This came in as spam a few minutes ago -- certainly sounds very interesting!!

Peter Singfield -- Belize

Return-Path: <newsdatasource@address.com>
From: "Irma Chaney" <newsdatasource@address.com>
To: snkm@btl.net
Subject: Product Offered
Date: Fri, 07 Mar 2003 00:00:55 +0500
X-CS-IP: 38.203.221.56
X-MASF: 0.00%

Content-Type: text/plain;

The revolutionary NightStar? magnetic force flashlight transforms simple
motion into light.

When gently shaken, a high strength magnet passes smoothly through a wire
coil efficiently generating electrical energy. A heavy duty capacitor
stores the energy and delivers power to a bright white LED - just 30
seconds of shaking provides 20 minutes of light!!

Superior to a battery, the capacitor will never corrode, can be re-charged
several hundred thousand times and will power the LED even under extreme
hot and cold temperatures.

Equally impressive, the solid state LED is practically unbreakable and has
a rated lifetime of tens of thousands of hours; in total darkness the
NightStar? illuminates a 12ft diameter area from a distance of 50ft. The
state of the art components are all contained within a lightweight
polycarbonate casing, which is waterproof, corrosion proof, and virtually
indestructible

In Short the best torch in the world, EVER!

Visit us for more information at:

http://www.nightstartorch.com

From snkm at BTL.NET Fri Jun 18 08:49:11 2004
From: snkm at BTL.NET (Peter Singfield)
Date: Tue Aug 10 18:31:16 2004
Subject: Illuminating with LED
Message-ID: <FRI.18.JUN.2004.064911.0600.SNKM@BTL.NET>

Dear A.D.;

I to picked up on this -- see appended for text dump of their WWW site.

Note this:

"Only ?33.95 including postage and packing"

Very expensive!! Still -- a concept easy to reverse engineer --

Many years back we played with linear alternators. I still have some
excellent papers on this subject.

At the Url below one sees nice pictures of this present device. Hard to
understand this high price!!

Guess we wait for India or China to start production??

Peter / Belize

At 12:00 PM 6/18/2004 +0530, adkarve wrote:
> Dear Stovers,
> I got this message today, which might be of interest to some in cotext with
>lighting with LED.
> A.D.Karve

*****************appended*************

http://www.nightstartorch.com/

The revolutionary NightStar? magnetic force flashlight transforms simple
motion into light.

Superior to a battery, the capacitor will never corrode, can be re-charged
several hundred thousand times and will power the LED even under extreme
hot and cold temperatures.

Only ?33.95 including postage and packing

From rbadhi at HOTMAIL.COM Fri Jun 18 19:27:46 2004
From: rbadhi at HOTMAIL.COM (R. B. Adhikari)
Date: Tue Aug 10 18:31:16 2004
Subject: LISTSERV PASSWORD
Message-ID: <FRI.18.JUN.2004.192746.0400.RBADHI@HOTMAIL.COM>

I want to get a new LISTSERV password as follows to log in:

TANSEN
Please confirm.

Regards

R. B. Adhikari

From adkarve at PN2.VSNL.NET.IN Fri Jun 18 09:55:18 2004
From: adkarve at PN2.VSNL.NET.IN (adkarve)
Date: Tue Aug 10 18:31:16 2004
Subject: bamboo in the North-east of India
Message-ID: <FRI.18.JUN.2004.192518.0530.ADKARVE@PN2.VSNL.NET.IN>

Dear Crispin
the flowering cycle period changes from species to species. In the case of
the North-east Indian bamboo, the last flowering occured around 1950. The
rodent population encreases due to the abundance of bamboo seed, and after
the rodents have eaten all the bamboo seed in the forests, they invade the
fields of the local farmers, causing a famine. The way suggested by me is to
harvest all the bamboo before it has flowered, convert it into charcoal, so
that it does not rot, and prevent the multiplication of rodents.
Yours
A.D.Karve
----- Original Message -----
From: Crispin Pemberton-Pigott <crispin@newdawn.sz>
To: <STOVES@LISTSERV.REPP.ORG>
Sent: Friday, June 18, 2004 5:13 PM
Subject: Re: [STOVES] bamboo in the North-east of India

> Dear Karve
>
> Is it true that the bamboo flowers about every 150 years? Then it dies,
> right? I seem to remember reading this caused a lot of famine in the 19th
> century.
>
> Thanks
> Crispin

From takeda at SONIC.NET Sat Jun 19 06:05:09 2004
From: takeda at SONIC.NET (Matthew Takeda)
Date: Tue Aug 10 18:31:16 2004
Subject: Simple solution to lighting
In-Reply-To: <200406190401.i5J41V728339@ns1.repp.org>
Message-ID: <SAT.19.JUN.2004.030509.0700.TAKEDA@SONIC.NET>

Peter Singfield wrote:
>This came in as spam a few minutes ago -- certainly sounds very interesting!!
>
>From: "Irma Chaney" <newsdatasource@address.com>
>Subject: Product Offered
>
>The revolutionary NightStar? magnetic force flashlight transforms simple
>motion into light.

Ken Boak posted a link to one of these and Laren Corie posted a couple of
links to do-it-yourself versions less than two weeks ago in this list.

I have a NightStar that someone gave me for Christmas a couple of years
ago. It works as advertised, but with only one white LED, it's useful but
not terribly bright.

Matthew Takeda
the JOAT
From larencorie at AXILAR.NET Sat Jun 19 05:41:34 2004
From: larencorie at AXILAR.NET (LarenCorie)
Date: Tue Aug 10 18:31:16 2004
Subject: Illuminating with LED
Message-ID: <SAT.19.JUN.2004.054134.0400.LARENCORIE@AXILAR.NET>

> > The revolutionary NightStar? magnetic force flashlight
> > transforms simple motion into light. When gently shaken,
> > a high strength magnet passes smoothly through a wire
> > coil efficiently generating electrical energy. A heavy
> > duty capacitor stores the energy and delivers power to
> > a bright white LED - just 30 seconds of shaking
> > provides 20 minutes of light!!

http://www.creative-science.org.uk/gensimple1.html
http://www.amasci.com/amateur/coilgen.html

-Laren Corie-

From Gavin at AA3GENERGI.FORCE9.CO.UK Sat Jun 19 13:51:19 2004
From: Gavin at AA3GENERGI.FORCE9.CO.UK (Gavin Gulliver-Goodall)
Date: Tue Aug 10 18:31:16 2004
Subject: Lemon Light
In-Reply-To: <LISTSERV%2004061615172064@LISTSERV.REPP.ORG>
Message-ID: <SAT.19.JUN.2004.185119.0100.GAVIN@AA3GENERGI.FORCE9.CO.UK>

Come on chaps,
All batteries are ion exchange (electron exchange devices, the acid is the
medium to facilitiate this. In a copper-zinc battery the zinc is eaten away
and deposited on the copper ..
Zinc- copper is not a reversible reaction whereas the lead -acid , li-ion
etc are . LI-ion has a larger charge density and low mass- great for phones
but not otherwise the best for other applications.
So apotato or other fruit is a facilitor for ion exchange between 2
disimilar metals.

Slowly we remember our fundamental physics!!

So to summarise you need not to look for exotic fruit but indigenous (or
readily available without an alternative high value)Ion exchange pairs (not
pears) with a high potential difference

Good luck

Gaivn

From crispin at NEWDAWN.SZ Sat Jun 19 18:21:41 2004
From: crispin at NEWDAWN.SZ (Crispin Pemberton-Pigott)
Date: Tue Aug 10 18:31:16 2004
Subject: Fertilizer powered refrigerator
Message-ID: <SUN.20.JUN.2004.002141.0200.>

Dear Stovers

I received the following today from David Christer in Johannesburg:

"I have attended an interesting conference run by the Design Institute
of South Africa. It started with design awards for young designers. The
winner from Pretoria had designed a insulated cooler box which was
cooled by fertiliser. The fertiliser was then sold onto the farmer to
subsidise costs."

Urea powered perhaps?

Regards
Crispin

From snkm at BTL.NET Sun Jun 20 15:02:08 2004
From: snkm at BTL.NET (Peter Singfield)
Date: Tue Aug 10 18:31:16 2004
Subject: Wastewater-Fueled Device Produces Electricity
Message-ID: <SUN.20.JUN.2004.130208.0600.SNKM@BTL.NET>

Why this might be of interest:

He notes that they have hooked up an MFC built on the Penn State design
principles to run a three-milliWatt fan. Calculations show that a typical
wastewater treatment plant that had a Penn State MFC in place could power
the fan with just 5.5 oz of wastewater or a reactor smaller than a teacup.

The new prototype consists of carbon paper placed on opposite ends of a
plastic tube about an inch and a half long and a little over an inch in
diameter. Carbon paper on one end is the anode and carbon paper, which also
contains a small amount of platinum, forms the cathode on the other end.
Platinum wire completes the circuit. The carbon paper allows oxygen in air
to directly react at the cathode. So, there is no need to bubble air into
the water at the cathode as is required in a typical two chamber MFC.

**************************************************

http://www.spacedaily.com/news/energy-tech-04zq.html

(picture of device at that Url)

ENERGY TECH

Cheaper Wastewater-Fueled Device Produces More Electricity

just add water

University Park PA - Jun 16, 2004

Penn State environmental engineers have removed and replaced one of the
most expensive parts of their prototype microbial fuel cell and the device
now costs two-thirds less and produces nearly six times more electricity
from domestic wastewater. Earlier this year, the Penn State team was the
first to develop a microbial fuel cell (MFC) that can generate electricity
while simultaneously cleaning domestic wastewater skimmed from the settling
pond of a sewage treatment plant.
Now, they've shown that by modifying their original MFC to make it cheaper,
they can also boost electricity production from about 26 milliwatts per
square meter to about 146 milliwatts per square meter.

Dr. Bruce Logan, the Kappe professor of environmental engineering, directs
the project. He says, "The new design has moved the technology closer to
our goal of 1000 milliwatts per square meter."

The advance is described in a paper, Electricity Generation Using an
Air-Cathode Single Chamber Microbial Fuel Cell in the Presence and Absence
of a Proton Exchange Membrane, released online and scheduled for a future
issue of Environmental Science and Technology. The authors are Dr. Hong
Liu, postdoctoral researcher in environmental engineering, and Logan.

The Penn State team modified their original fuel cell by removing the
polymeric proton exchange membrane (PEM) that previously was bonded to the
cathode and substituting carbon paper for the electrodes.

Microbial fuel cells produce current through the action of bacteria that
can pass electrons to an anode, the negative electrode of a fuel cell. The
electrons flow from the anode through a wire to a cathode, the positive
electrode of a fuel cell, where they combine with hydrogen ions (protons)
and oxygen to form water.

The naturally-occurring bacteria in wastewater drive power production via a
reaction that allows them to transport electrons from their cell surface to
the anode. In addition, a reaction (oxidation) that occurs in the interior
of the bacterial cell lowers the biochemical oxygen demand, cleaning the
water.

Logan notes, "By eliminating the PEM, which was one of the most expensive
components, we bring the cost down significantly. Substituting carbon paper
for graphite rods further reduces the cost. I'm optimistic that MFCs may be
able to help reduce the $25 billion annual cost of wastewater treatment in
the U.S. and provide access to sanitation technologies to countries
throughout the world."

From psanders at ILSTU.EDU Sun Jun 20 16:16:53 2004
From: psanders at ILSTU.EDU (Paul S. Anderson)
Date: Tue Aug 10 18:31:16 2004
Subject: Illuminating with LED
In-Reply-To: <3.0.32.20040618064809.00984b00@pop.btl.net>
Message-ID: <SUN.20.JUN.2004.151653.0500.PSANDERS@ILSTU.EDU>

Stover.

We have been hit by SPAM about a device of interest, and Peter mentions
"reverse engineering". Interesting: reverse engineering of a Spam item!!

Seriously, we need to consider if the technique can benefit our target
populations, and at a cost that is manageable for the benefits gained.

Yesterday (before seeing this spam item) I bought my first LEDs and am
anxious to get experimenting with the Lemon Light.

Can a capacitor assist with the Lemon Light concept? A capacitor is sort
of like a small battery (storage of power), right?

Paul

At 06:49 AM 6/18/04 -0600, Peter Singfield wrote:
>Dear A.D.;
>
>I too picked up on this -- see appended for text dump of their WWW site.
>
>Note this:
>
>"Only ?33.95 including postage and packing"
>
>Very expensive!! Still -- a concept easy to reverse engineer --

From snkm at BTL.NET Sun Jun 20 17:56:25 2004
From: snkm at BTL.NET (Peter Singfield)
Date: Tue Aug 10 18:31:16 2004
Subject: Illuminating with LED
Message-ID: <SUN.20.JUN.2004.155625.0600.SNKM@BTL.NET>

Reverse engineering --

As in you now considering using a capacitor -- so -- study how to make one
that stores enough. It can be done easily.

As for a reciprocating alternator -- try a thin walled tube with a round
magnet inside. Make the tube 3X the lengh of the magnet -- wrap a coil of
sufficent turns around the middle outside -- hook up the coil to the cap --
the LED from the cap.

Take tube and shake.

Peter

At 03:16 PM 6/20/2004 -0500, Paul S. Anderson wrote:
>Stover.
>
>We have been hit by SPAM about a device of interest, and Peter mentions
>"reverse engineering". Interesting: reverse engineering of a Spam item!!
>
>Seriously, we need to consider if the technique can benefit our target
>populations, and at a cost that is manageable for the benefits gained.
>
>Yesterday (before seeing this spam item) I bought my first LEDs and am
>anxious to get experimenting with the Lemon Light.
>
>Can a capacitor assist with the Lemon Light concept? A capacitor is sort
>of like a small battery (storage of power), right?
>
>Paul
>
>At 06:49 AM 6/18/04 -0600, Peter Singfield wrote:
>>Dear A.D.;
>>
>>I too picked up on this -- see appended for text dump of their WWW site.
>>
>>Note this:
>>
>>"Only ?33.95 including postage and packing"
>>
>>Very expensive!! Still -- a concept easy to reverse engineer --
>
>Paul S. Anderson, Ph.D.
>Dept of Geography - Geology (Box 4400), Illinois State University
>Normal, IL 61790-4400 Voice: 309-438-7360; FAX: 309-438-5310
>E-mail: psanders@ilstu.edu - Internet items: www.ilstu.edu/~psanders
>NOTE: Retired from teaching. Active in Stoves development.
>For fastest contact, please call home phone: 309-452-7072
>
>

From Gavin at AA3GENERGI.FORCE9.CO.UK Sun Jun 20 19:18:19 2004
From: Gavin at AA3GENERGI.FORCE9.CO.UK (Gavin Gulliver-Goodall)
Date: Tue Aug 10 18:31:16 2004
Subject: Illuminating with LED
In-Reply-To: <3.0.32.20040620142809.00a417a0@pop.btl.net>
Message-ID: <MON.21.JUN.2004.001819.0100.GAVIN@AA3GENERGI.FORCE9.CO.UK>

Peter,
To charge and discharge the capacitor you will need 2 diodes and a switch
(one can be the LED) or better a bridge of 4 diodes so that both strokes
will help charge the device.

It is still, not hard and not expensive.
Good luck
Gavin

Reverse engineering --

As in you now considering using a capacitor -- so -- study how to make one
that stores enough. It can be done easily.

Take tube and shake.

Peter

At 03:16 PM 6/20/2004 -0500, Paul S. Anderson wrote:
>Stover.
>
>We have been hit by SPAM about a device of interest, and Peter mentions
>"reverse engineering". Interesting: reverse engineering of a Spam
item!!
>
>Seriously, we need to consider if the technique can benefit our target
>populations, and at a cost that is manageable for the benefits gained.
>
>Yesterday (before seeing this spam item) I bought my first LEDs and am
>anxious to get experimenting with the Lemon Light.
>
>Can a capacitor assist with the Lemon Light concept? A capacitor is sort
>of like a small battery (storage of power), right?
>
>Paul
>
>At 06:49 AM 6/18/04 -0600, Peter Singfield wrote:
>>Dear A.D.;
>>
>>I too picked up on this -- see appended for text dump of their WWW site.
>>
>>Note this:
>>
>>"Only ?33.95 including postage and packing"
>>
>>Very expensive!! Still -- a concept easy to reverse engineer --
>
>Paul S. Anderson, Ph.D.
>Dept of Geography - Geology (Box 4400), Illinois State University
>Normal, IL 61790-4400 Voice: 309-438-7360; FAX: 309-438-5310
>E-mail: psanders@ilstu.edu - Internet items: www.ilstu.edu/~psanders
>NOTE: Retired from teaching. Active in Stoves development.
>For fastest contact, please call home phone: 309-452-7072
>
>

From snkm at BTL.NET Sun Jun 20 19:17:27 2004
From: snkm at BTL.NET (Peter Singfield)
Date: Tue Aug 10 18:31:16 2004
Subject: Illuminating with LED
Message-ID: <SUN.20.JUN.2004.171727.0600.SNKM@BTL.NET>

Right on Galvin!!

At 12:18 AM 6/21/2004 +0100, Gavin Gulliver-Goodall wrote:
>Peter,
>To charge and discharge the capacitor you will need 2 diodes and a switch
>(one can be the LED) or better a bridge of 4 diodes so that both strokes
>will help charge the device.
>
>It is still, not hard and not expensive.
>Good luck
>Gavin
>

From bakaryj at GAMTEL.GM Mon Jun 21 04:40:53 2004
From: bakaryj at GAMTEL.GM (Bakary Jatta)
Date: Tue Aug 10 18:31:16 2004
Subject: STOVES Digest - 5 Jun 2004 to 6 Jun 2004 (#2004-134)
Message-ID: <MON.21.JUN.2004.084053.0000.BAKARYJ@GAMTEL.GM>

----- Original Message -----
From: "Automatic digest processor" <LISTSERV@LISTSERV.REPP.ORG>
To: "Recipients of STOVES digests" <STOVES@LISTSERV.REPP.ORG>
Sent: Monday, June 07, 2004 4:00 AM
Subject: STOVES Digest - 5 Jun 2004 to 6 Jun 2004 (#2004-134)

> There are 13 messages totalling 874 lines in this issue.
>
> Topics of the day:
>
> 1. Heat from radiation v.s. conduction using shiny (real) pots (4)
> 2. use of outside air with analysis KR
> 3. Flames for lighting
> 4. Flaming Resin For Jumla
> 5. which emission is more important measuring
> 6. Lights--especially CFL
> 7. Bricks from Ken Goyer
> 8. [ethos] Bricks from Ken Goyer (2)
> 9. Absortion chillers using our heat
>
> ----------------------------------------------------------------------
>
> Date: Sun, 6 Jun 2004 15:59:28 +0200
> From: Crispin Pemberton-Pigott <crispin@NEWDAWN.SZ>
> Subject: Re: Heat from radiation v.s. conduction using shiny (real) pots
>
> Dear Dr AD
>
> >Now we have to discourage housewives from
> >scrubbing the pots to a shine
>
> Quite so. I am not sure where the scrubbing should stop, but perhaps we
> need to look carefully at pot heat acquisition and retention.
>
> >I always thought that placing a pot on the Plancha
> >stove would be less efficient than placing the pot
> >directly on the fire.
>
> It probably is of the pot is battered. I was doing something that was
> going to show the influence of a reflective surface as I feel the
> subject is barely explored. Certainly nothing can be concluded in
> general just yet.
>
> >But your experiments indicate that the hot
> >plate of the Plancha was just what the doctor
> >ordered, at least in the case of shiny new pots.
>
> Yes. I have wondered about a black copper disk under new pots. I
> encourage everyone to try this experiment and see what results they get.
> Surely there will be some conflicting results which need to be discussed
> until we find a more efficient set of hardware.
>
> Suppose, for example, a No. 2 (nine litre) 3-legged pot were to be
> inverted in a plating plant and chromed from the top lip down to the
> midline. This may prevent a huge amount of energy from radiating from
> the upper charcoal-black, rough, cast iron surface. And the lid too for
> that matter. The bottom should be left black to pick up heat, the top
> chromed to retain it.
>
> What would be the maximum efficiency of a three stove fire when using
> such a pot? Surely it would be above the 33% figure Piet Visser got
> with his 'little-at-a-time' woodshaving-feeding experiments? That is
> why I keep mentioning the device-dependant nature of experimental
> results.
>
> >Your experiments give a new direction to stove designing.
>
> Well I agree with the assessment.
>
> I have written separately to Tami and Dr Prasad about the possiblity
> that the way in which heat shields work is not clear and also the
> possible over-rating of the effect of surface 'scrubbing' in the
> pot-to-heat shield gap.
>
> In very brief, if the heat shield is black, not shiny, is more heat
> transferred from the passing gas stream because the heat shield is able
> to radiate (by conversion) conductive heat directly to the pot a few mm
> away? If it is shiny and picks up hear from physical contact with
> shaking molecules of gas, and from radiating molecules and from the
> re-radiating pot surface, how will it radiate that heat over to the pot?
> The heat shield will get very hot but it will not be able to 'send' it
> to the pot if it is shiny.
>
> If we believe that only scrubbing is involved in assisting heat transfer
> from the gas stream to the pot, then the heat shield is primarily there
> to bring that gas stream into high velocity contact with the pot. If we
> accept that the heat shield is itself a potent radiator of conductive
> heat gathered from the passing gas stream, a radiator which is
> inherently higher in temperature than the water-cooled pot, one may
> indeed take a different approach to stove construction.
>
> For example - should the lower part of the heat shield be jet-black and
> the upper part chromed? This is to convert as much heat as possible
> from the convecting gases into radiated heat aimed at the pot. At some
> point as the gases cool, the effectiveness of this conversion to
> radiation drops to a point at which there should rather be a highly
> reflective surface to reflect heat radiating from passing hot molecules
> and re-radiation from the pot surface towards the pot. Where is this
> dividing line?
>
> Simlarly, at some point, a pot should change from an absorbtive to a
> retentive coating or finish.
>
> The pot is part of the stove.
>
> Regards
> Crispin
>
> ------------------------------
>
> Date: Sun, 6 Jun 2004 22:22:36 +0100
> From: Andrew Heggie <list@SYLVA.ICUKLIVE.CO.UK>
> Subject: Re: use of outside air with analysis KR
>
> On Mon, 31 May 2004 00:18:57 +0545, Kanchan Rai wrote:
>
> >For the passage of air on the ground might be insulated using locally
> >available material. A tree called silver porch is available in that
> >area, which has a paper like layers which is very good insulator. People
> >use such thing to insulate their roof.
>
> Kanchan, this sounds like silver birch, the betula family,
> characterised by an oily bark which finds many uses (canoes in the US)
> >
> >>
> >> So your numbers need to reflect the planned air changes for that size
> >> of room and the number of occupants as well.
> >
> >How much do you suggest the air changes for the room of size 10 feet *
> >12 feet with 8 feet height when burning rate is 2kg/hr ?
>
> We may be talking at cross purposes here, I was meaning air changes
> for the comfort and health of the occupants, which I felt was best
> incorporated into the combustion air, I've come back to nearly 100
> messages on Stoves (well done all) so I will take a while to catch up,
> I shall see what the recommended air changes are for a kitchen in UK.
>
> AJH
>
> ------------------------------
>
> Date: Sun, 6 Jun 2004 22:22:35 +0100
> From: Andrew Heggie <list@SYLVA.ICUKLIVE.CO.UK>
> Subject: Re: Flames for lighting
>
> On Thu, 27 May 2004 13:25:14 +0100, Peter Verhaart wrote:
> >I have changed the thread name to see if we can continue the
> >discussion of this aspect, I think it is still relevant to stoves even
> >though no longer relevant to cooking.
> >On Thu, 27 May 2004 09:45:20 +1000
>
> Snip
>
> >Anyone care to elaborate on what and how these nasties are formed,
> >currently I believe they are PICs formed when a hydrogen atom finds an
> >oxygen atom preferentially to the remaining carbon compound it split
> >from. So it is basically a lack of oxygen but why is it that this
> >sooty particle, probably with some nasty aromatic compound attached to
> >it, becomes so difficult to burn out? because the benzene ring, of the
> >attached aromatic is a stable one?
>
> I think polycyclic compounds are even more stable, like PCB's .
>
> > >Before you or I were even thought of, people burned aethyn (acetylene)
for
>
> >As you say an un premixed acetylene flame is very sooty, does it have
> >any especial luminance advantage over a candle flame? Definitely as
> >you add oxygen in the premix it firstly goes a brighter white before
> >the stable two cones of pale blue flame at stoichiometric mix.
>
> The acetylene flame is much hotter than the flame of straight chain
> alkanes
> because of the heat of dissociation of C2H2. This results in a much
> brighter flame and if it can be kept small enough it will not soot.
> Acetylene on the least provocation dissociates into, not surprisingly,
> hydrogen and carbon and quite a lot of heat. Added to this the heat of
> combustion of the hydrogen and some of the carbon and you have a
> bright
> almost white flame.
>
> >As to the small flame having better surface area I note that if you
> >light a single sheet of polythene it burns both cleanly and with a
> >bluish flame, put fire to a lot of polythene sacks and the result is a
> >smoky yellow flame.
>
> Between the single sheet and a lot of sacks there should be a luminous
> flame without soot or visible smoke.
>
> ------------------------------
>
> Date: Sun, 6 Jun 2004 22:24:01 +0100
> From: Andrew Heggie <list@SYLVA.ICUKLIVE.CO.UK>
> Subject: Re: Flaming Resin For Jumla
>
> On Fri, 4 Jun 2004 15:13:33 -0700, Rajendra Adhikari wrote:
>
> >Dear Stovers
> >
> >I am giving below the composition of pine resin usually found in Jumla,
Nepal:
> >
> >The pine species are: (a) Pinus roxburghii and (b) Pinus wallichiana.
>
> Rajendra, for the record the species I tapped was Pinus sylvestris.
>
> >The oleoresin on distillation yields about 16-20%w/w turpentine oil and
76-80% solid resin.
>
> What temperatures are used for distillation? In my time away the small
> amount I collected has solidified into a crumbly resin, do I take it
> this means these (valuable) volatile fractions have evaporated away?
>
> >Gas Liquid chromatography analysis of turpentine oil is roughly as
follows:
> >Hydrocarbons Mol. Formula %
> >Delta-3-carene C10H16 48.90
> >Alpha PInene C10H16 27.97
> >Beta Pinene C10H16 16.07
> >Para Cymene C10H14 6.83
> >Gamma Terpinene C10H16 0.23
> >Limonene C10H16 Trace
> >
> >May be somebody will find it useful to make smokeless resin lamp.
> >
> >In Nepal turpentine is costlier than kerosene.
>
> In which case as Kevin suggested it may better be collected as a cash
> crop and the remaining resin concentrated on for lighting, mind I feel
> the LED approach may be more benefit.
>
> Thanks for the chemical analysis.
>
> AJH
>
> ------------------------------
>
> Date: Sun, 6 Jun 2004 22:24:01 +0100
> From: Andrew Heggie <list@SYLVA.ICUKLIVE.CO.UK>
> Subject: Re: which emission is more important measuring
>
> On Sat, 5 Jun 2004 17:59:47 -0500, Tami Bond wrote:
>
> >Hello friends,
> >
> >Sorry to chime in late. I have been out of town too much, and the
> >discussion got really 'hot' after I left... Guess I should go out more...
>
> Tell me about it...
>
> Still better late than never, thanks.
>
> >There are some of my presentations at the last 3 years ETHOS meetings at:
> >http://cee.uiuc.edu/research/bondresearch/stoves.html
>
> Another one for my "to do" list ;-)
>
> >
> >We are also setting up one of these university labs of skeptical value
> >(wink, AJH) and the idea is to compare the results from fancy equipment
> >with cheaper equipment to determine just how cheap we can go, and still
be
> >useful to stovers like you.
>
> OK you misquote me slightly, I am skeptical of the cost benefit of
> work done in UK universities compared with the workers on the ground
> doing practical work, based on being "burnt" here, fundamental
> research is a different matter.
>
> Anyway over to the workers in Nepal now Tami has asked the 64 dollar
> question....
>
>
> >
> >Andrew wrote:
> >>I think you could do comparative tests by sucking a known volume of
> >>air through a tissue of fixed cross section. Then you can look at the
> >>dark disc formed by the particulates.
> >
> >Das and I have a disagreement on this-- he thinks smoke shade is okay, I
> >don't. I don't like smoke shade because some of the particles from wood
> >combustion aren't black, so there's not a great relationship between
total
> >mass and color.
>
> Thanks that's well worth considering.
>
> AJH
>
> ------------------------------
>
> Date: Sun, 6 Jun 2004 22:24:02 +0100
> From: Andrew Heggie <list@SYLVA.ICUKLIVE.CO.UK>
> Subject: Re: Heat from radiation v.s. conduction using shiny (real) pots
>
> On Sat, 5 Jun 2004 00:54:38 +0200, Crispin Pemberton-Pigott wrote:
>
> >Dear Lanny
> >
> >>I had not thought about radiant heat reflecting back
> >>off of the pot.
> >
> >You are not alone. The 'books' seem to understand that it is a black
> >body receiving heat and remaining at a low temperature because of the
> >water inside.
>
> Crispin, I am too way behind to catch up on all this, I still have 44
> unread stoves messages, so I'll just add a few further points and
> maybe pick up on your specific ones later. I'm not a teacher and I may
> well be wrong, I am willing to play Aunt Sally to provoke a bit of
> discussion, though this was going well enough before I returned.
>
> Firstly I am sure most heat transfer in domestic cooking stoves takes
> place via convection and conduction. However in industry the opposite
> is often the case, this is caused by a number of factors, not least of
> which is that industrial scale burning takes place as near to
> stoichiometric as possible, so the flame temperatures are much higher,
> as radiation effects are related to the fourth power of the absolute
> temperature you can see how a 2200K flame can emit a lot of radiative
> power compared with a 900K wood stove.
>
> Another point is that reflectivity and emissivity are two different
> physical properties, so a good reflector may also radiate its heat
> away. Also I agree your point that the angle subtended by the pot
> looking at the flame is less than the angle through which the pot can
> radiate away its heat, so again the radiation effect is asymmetrical
> BUT the pot is at a lower temperature (normally <370K) so it emits
> radiation at a less energetic wavelength than the fire.
>
> AJH
>
> ------------------------------
>
> Date: Sun, 6 Jun 2004 13:38:08 -0400
> From: LarenCorie <larencorie@AXILAR.NET>
> Subject: Re: Heat from radiation v.s. conduction using shiny (real) pots
>
> Crispin Pemberton-Pigott <crispin@NEWDAWN.SZ> wrote;
>
> > How's this: heat radiates from any surface after conductive heat has
> > been picked up. Heat is radiating all over the place all the time. It
> > radiates off houses and reflects back from trees at night.
>
> It doesn't reflect back from trees very much.
> Trees are seldom warmer, and absorb infrared quite well.
>
> > The problem is if you make the surface optimized to pick up heat,
>
> Absorb.
>
> > you are possibly also losing more than you used to.
>
> Emit
>
> > There is little point in working hard to pick up more heat
> > if you are going to lose it again.
>
> > Now think about this: suppose you make a surface 10 times more
> > effective at picking up conductive heat from hot gases passing by.
>
> The is not "conduction." That is "convection"
>
> It can be increased by increasing 1) surface area (relative
> to the gas interface. 2) velocity of the gas over the surface,
> thereby reducing the Rvalue of the surface film.
>
> > And you accidentally, by chance, increase the radiation
> > coefficient by a factor of 20.
>
> That would be impossible. Very shiny polished metal only
> has an emissivity of about .05 20 time that would 1, or
> the emissivity of a "perfect black body" a perfect emitter.
>
> > Will it will gain more heat and lose even more?
> > Surely there is a model to maximize this gain and
> > minimize the loss?
>
> That basic problem is that the temperature you wish to absorb,
> and the temperature that you wish to not emit, are very similar.
> Therfore their wavelength is also very similar. There are selective
> surfaces, which function very well to distingush the difference
> between visible light, and log wave length infrared. IIRC they
> are in the range of about 20 microns or 1/10,000 inch. (might
> be off) Anyway, it is relatively easy to make a surface that will
> absorb light very well (up to 96%) yet have an emissivity as
> low as even 6%. However, such a surface cannot be exposed
> to any amount of particulates, or the surface quickly becomes
> fouled, and loses its low emissivity. As a result, cheaper, less
> selective surfaces are more popular. Not only are selective
> surfaces used on solar collector absorbers, but they are even
> more poplar as glass coating. The "E" in Lo-E glass stand for
> "emissivity" It is a very then layer of metal (copper based
> I believe) that is sputtered out onto the glass, so thinly that
> it can be seen through. There is also selectivity in paints.
> Laquers tend to emit less than the same color enamels or
> acrylics. There are special low emissivity paints with
> Es as low as 0.4. White is an interesting color. It can
> absorb as little as 10% of visible light, yet still emit
> basically as well as any other color, like a black that
> absorb 95% of the visible light. Again, this works
> because of the great difference in wavelength between
> visible light and the long wave length, relatively cool,
> infrared that is emitted in livable human environments.
> We may think a gasifier gets hot, but the sun it is not.
> The pot surface is about the same temperature as the
> gas, and it is too easy to foul, so a selective surface
> is not practical.
>
> > One thing is for sure, don't polish the bottom of your pots.
>
> That really depends. Since it is not possible to be selective
> about the gains from radiation, or even convection, then we
> must look to the option of conductive gain. If we can bring
> the heat to the pot via direct contact with a hot object, then
> the super low emissivity of the polished surface will help it
> to retain the heat and get much hotter before reaching
> equalibrium. Notice how much hotter a piece of polished
> metal will get, out in the sun, than one that is painted white,
> even though the white one will be absorbing about twice
> as much energy. The white one, however, emits at a rate that
> is as much as 18 times greater than the polished surface.
> It you can get the heat into the pot, it will stay there far
> better, if the pot is polished.
>
> So, We want to.......
>
> 1) absorb radiant energy into a burner
> 2) absorb into the burner via convection
> 3) transfer the heat from the burner to the pot via conduction.
> 4) reduce radiant heat loss from the pot via a polished surface
> 5) reduce convective heat loss from the pot
> 6) perhaps reduce evaporative heat loss from the pot contents
>
> > Today I received 2 sheets of 3CR12 - 3mm. They are as black
> > as good old scale-covered mild steel. In fact I wasn't sure they
> > were stainless and we complained. I suspect these had missed
> > getting into the pickling bath. They would be far better at
> > picking up heat than the regular silvery finish.
>
> Just in absorbing radiation.
>
> > When you weld stainless steel it goes black on the surface from
> > high temperature oxidation. It is 'shiny' because it is smooth
> > (even a black car can be shiny) but it is probably possible to
> > blacken the bottom of a stainless steel pot with some sort of
> > treatment.
>
> Surfaces like that sometimes are in the right thickness range
> to exhibit selective radiation properties. Black chrome is a
> very popular selective surface for solar collectors. It is also
> used on things like cameras and furniture. Black chrome
> furniture can be literally dangerous in the sun. It can
> reach temperatures high enough to cause injury.
>
> > What about gun blue?
>
> There would doubtfully be no advantage. There is no selectivity.
>
> > Low tech electroplating? Hard chroming is pretty dark.
> > When I made IMAX camera parts back in my youth they
> > were all hard chromed and are not bright. The case was
> > anodized flat black
>
> Again, it is possible to control the process to the point where
> the surface can distiguish between the tiny wavelength of
> visible light, and the long wavelength of fairly cool infrared,
> but it is not going to be able to tell the difference between
> the flame and the pot. Even if it could the exposed surface
> would very quickly become fouled, and lose its selectivity.
>
> > Aluminum can be anodized several different colours. Can
> > we anodize the bottom part of polished aluminum pots flat
> > black?
>
> Using a polish surface on the sides, and a colored surface on
> the bottom is a good idea. It need not be black. We are not
> dealing with enough visible light for that to matter. It could
> be blue, or red, or green, or gray. They all absorb and emit
> IR basically the same. I like this idea of "selective orientation"
> It is sort of like bonding the "burner" I referred to above,
> permanently to the bottom of the pot. I am pretty sure that
> there are pans on the market that use a rough cast dark surface
> on the bottom, that even has veins to increase turbulence, as
> well as surface are, then the sides are polished. Good design.
>
> > With what? Car batteries in parallel? Who knows about
> > black anodizing?
>
> Perhaps the bottom should not be polished, but cast with a
> rough finish. That would increase the heat exchanger surface
> area, but may capture a thin film of dead air, which might
> reduce heat flux, however the orientation of the pot above
> the heat source, plus the degree of convection should be
> able to break up most any surface film. This get complicated.
> I can not even venture a good guess as to the optimal degree
> of surface texture. It needs empirical testing.
>
> > The solar cooker pots available in RSA are painted black.
> > Not very satisfactory.
>
> It is an interesting thought, that they might be more efficient
> with the side toward the reflector colored black, and the side
> facing the sun, which would not have the concentration, as a
> polished surface. It would reflect back the direct sunlight,
> but it would also reduce the emissision, from that front
> surface (50% view factor), by as much as 90%, so it
> would have a higher net gain/loss ratio, and would be
> able to hit higher temperatures. Lose a litte, gain a
> little more.
>
> > Cooking over wood gives a nice even black finish
> > which will bake on well if you don't wash it too
> > hard on the outside. How much more effective
> > is such a pot at picking up and retaining heat?
>
> Isn't it nice, that things happen so naturally, if you just
> let them ;O) Of course the sides can also get covered
> with soot too, Don't wash those pans ;O)
>
> > It seems obvious to me that the pot should sit into the
> > heat shield at least part way and that part should be black,
> > especially flat/matte black. Outside it should shine like a
> > mirror to retain the heat.
>
> Yes
>
> > All this raise another question: should the heat shield be
> > reflective to send heat radiating from the pot surface back,
> > or black to pick up heat from the passing gasses and radiate
> > it to the pot?
>
> It depends on which is hotter. It can be said that heat only
> moves in one direction, toward cold. If it is hotter than the
> pot, it is by definition, not a shield, and if it is really a shield,
> then it will serve its function better if it is also a radiant
> shield, so polished.
>
> > A black heat shield can get very hot and will re-radiate what
> > comes from the pot,
>
> Re-radiate to what?
> Black is not a factor. It will function the same in any color.
> This is the IR spectrum. Polished is not a color.
>
> > and accumulate and radiate heat from passing gasses.
>
> Yes. It will not function as a heat shield if it is hoter than the pot.
> It will also convect and radiate much heat from its exterior side,
> unless it is insulated.
>
> > A shiny silver heat shield around a shiny silver pot is
> > nearly useless.
>
> It is at least redundant, when they are new. A 95%
> reduction, of a 95% reduction is hardly worthwhile.
> However, in the real world of cooking polished
> surfaces get fouled, which happens extremely easily.
> When they do, they lose most of their effectiveness,
> and a backup polished surface is a very good idea.
>
> > Interesting.
>
> Very........great subject, and discussion. this is fun ;O)
>
> -Laren Corie-
> Passive Solar Building Design Since 1975 (retired)
>
> ------------------------------
>
> Date: Sun, 6 Jun 2004 23:13:44 +0100
> From: Andrew Heggie <list@SYLVA.ICUKLIVE.CO.UK>
> Subject: Re: Lights--especially CFL
>
> On Tue, 1 Jun 2004 15:15:36 -0700, David Neeley wrote:
>
> >
> >All of which said, if you can produce sufficient
> >electricity from the stoves, I would completely agree that
> >a CFL that runs on the current produced would be the most
> >cost-efficient light source available today.
>
> This is my take, the high frequency CFL is the most electricity
> efficient at domestic lighting levels.
> >
> >In my opinion, LED lights are best where portability or
> >very long life are more important than individual cost.
>
> Which just goes to illustrate that there is more in the total life
> cost than energy efficiency alone.
>
> >Thus, traffic signals, automotive brake lights,
> >flashlights, and similar applications are becoming very
> >popular.
>
> OK this is a special case where the LED has the advantage of
> outputting light at the required frequency (colour), most other
> (rapidly switching) lights would require a colour filter which
> effectively block light, thus reducing the lumens leaving the device
> for the input wattage.
>
> AJH
>
> ------------------------------
>
> Date: Sun, 6 Jun 2004 15:28:05 -0700
> From: Dean Still <dstill@EPUD.NET>
> Subject: Re: Bricks from Ken Goyer
>
> Dear Kanchan Rai,
>
> Ken is off to Ghana to help with a stove project. We give the bricks to
> local brick makers who usually fire for a day at around 850 to 1050C.
These
> are wood or trash burning kilns.
>
> Best,
>
> Dean
>
> ------------------------------
>
> Date: Sun, 6 Jun 2004 16:50:27 -0700
> From: ken goyer <kgoyer@COMCAST.NET>
> Subject: Re: [ethos] Bricks from Ken Goyer
>
> Dear Kachan, I started making ceramics test pieces and bricks using an
> electric kiln such as potters use. At first, I fired very slowly to
> eliminate water and burn out organic matter and then raised the
> temperature faster. Usually I took about twelve hours to reach 1050 oC
> or cone 03. Now I am amazed to discover that just about anything you do
> to fire bricks works as long as you can get them to be red hot. Even if
> you go fast. I'm sorry that I don't have the time right now to post some
> pictures of kilns that have worked. Like I said, I am amazed, almost any
> contained space to which you can apply heat long enough seems to work.
> The economy of scale with bricks is in making thousands of them at once.
> Best regards, Ken Goyer
>
> Kanchan Rai wrote:
>
> >Dear ken goyer,
> >thanks for providing information on clay and bricks. Could you tell me
> >what kind of kiln are you using for baking bricks, how long do you bake
> >at what temperature?
> >
> >kanchan
> >
> >
> >
> >>Dear Friends, If the brick is particularly weak or won't hold
> >>together when fired it is probably the fault of the clay. All clays
> >>are not equal. Brick makers should know their clay body and how to
> >>adjust it. If you don't have the luxury of someone else's experience
> >>then making experiments is the best way to find out. Good clay has
> >>certain well known properties which vary depending on the use that you
> >>have in mind. Fortunately, our ceramics are very forgiving of much of
> >>the criteria that potters expect.. We don't care what color it becomes
> >>when fired or how thin you can turn it on a wheel. If you can make a
> >>ball of wet clay in your hand and it sticks together, that is a good
> >>sign. If you can drop the ball to the ground and it flattens but
> >>doesn't splatter, that is a good sign. Many other tests can be
> >>performed to determine it's shrinkage and firing point etc. These
> >>tests are described in most beginning pottery books.
> >> Clay can be improved by processing if necessary. One method would
> >>be
> >>to stir up a pond of clay with a beast (an animal like a horse or
> >>oxen). The mud that goes into suspension is decanted off to another
> >>pond where it is allowed to settle. This way sand and other impurities
> >>are removes and the smaller clay particles are hi-graded. Potters
> >>sometimes use a barrel with a motor driven propeller to stir up a
> >>slurry of clay allowing heavies to settle and then drain off the fine
> >>particles into another barrel. But this will not produce enough clay
> >>for a high production operation. The best solution is to find a good
> >>clean clay body sufficient for your needs for a long time.
> >> I don't understand why your bricks won't dry, unless it's raining
> >>all of the time or the humidity is extremely high. I have never had
> >>drying problems when using sawdust. I have had drying problems when
> >>using paper, newspaper, cardboard, flour, and some types of ground up
> >>vegetables. I like to use cement in a brick. The brick will harden in
> >>a day and then it can be handled and turned so more sides are exposed
> >>to the air. Also the brick will shrink less. I have made many
> >>successful bricks with no cement as well. It might take a brick a week
> >>to dry completely. Here in Oregon in the rainy season (most of the
> >>time) I like to dry bricks indoors. Often times, due to lack of
> >>patience, we are trying to fire wet bricks. If you proceed very slowly
> >>this seems to work. The brick is force dried and then the temperature
> >> is raised to burn out the organic matter and so on.
> >> The important thing is that you keep on experimenting and
> >>eventually
> >>the solution will appear. Keep asking questions too! Best of luck!
> >>Ken Goyer
> >>
> >>
> >
> >
> >
> >
> >
> >
>
> ------------------------------
>
> Date: Sun, 6 Jun 2004 17:37:05 -0700
> From: David Neeley <dbneeley@YAHOO.COM>
> Subject: Re: Heat from radiation v.s. conduction using shiny (real) pots
>
> Crispin's account was fascinating. However, I have one
> question. In his conclusion:
>
> "Conclusion: I think this radiated heat business needs a
> good looking into.
> "On the face of it, conduction was a far stronger deliverer
> of heat to a clean aluminum pot than radiation was. If I
> had used polished stainless steel the effect would have
> been even more pronounced. It is possible
> that conduction of heat to shiny pots is much more
> important, perhaps by an order of magnitude, than it has
> been given credit for."
>
> Why do you think the polished stainless would have an "even
> more pronounced effect" than the aluminum pot?
>
> I presume you assume the more reflective surface would
> absorb less radiant heat...and with that I would agree.
>
> However, aluminum is a superior *conductor* of heat to
> stainless steel...so perhaps the difference would not be as
> substantial as you may assume?
>
> As for radiant heat, I think the conclusion should not be
> so surprising. Solar cookers have long used black pots for
> this very reason...the solar energy hits the black pot and
> its wavelength is changed to heat.
>
> Perhaps the best solution within a fairly reasonable cost
> might be a black-anodized aluminum pot--to get the best of
> both worlds of radiation and convection.
>
> Regards,
>
> David
>
>
>
>
> __________________________________
> Do you Yahoo!?
> Friends. Fun. Try the all-new Yahoo! Messenger.
> http://messenger.yahoo.com/
>
> ------------------------------
>
> Date: Sun, 6 Jun 2004 17:48:41 -0700
> From: Matthew Takeda <takeda@SONIC.NET>
> Subject: Re: Absortion chillers using our heat
>
> --=======4474FB=======
> Content-Type: text/plain; x-avg-checked=avg-ok-681B379B; charset=us-ascii;
format=flowed
> Content-Transfer-Encoding: 8bit
>
> Paul S. Anderson wrote:
> >NOW my question is, what can be made at LOW cost for developing
> >countries? I am thinking of cool, not cold, (to freeze water would be
> >nice, but that is not as important as cool so that milk, etc does not
spoil.)
>
> Paul -
>
> Have you looked into intermittent zeolite sorption cooling?
>
> <http://www.eg-solar.de/english/products/solarrefrig.htm>
> <http://193.175.120.23/an/pt/solar/publish/euros-00.pdf>
>
>
> Matthew Takeda
> the JOAT
>
> --=======4474FB=======--
>
> ------------------------------
>
> Date: Sun, 6 Jun 2004 20:32:43 -0700
> From: Tom Miles <tmiles@TRMILES.COM>
> Subject: Re: [ethos] Bricks from Ken Goyer
>
> Kanchan Rai
>
> Use the "FIND" search on the stoves web page. Of the 53 links some will =
> be helpful. I can tell that we need to do a good section on kilns.
>
> Regards,
>
> Tom Miles
> http://www.repp.org/discussiongroups/resources/stoves/
> ----- Original Message -----=20
> From: ken goyer=20
> To: Kanchan Rai ; STOVES@LISTSERV.REPP.ORG ; ethos=20
> Sent: Sunday, June 06, 2004 4:50 PM
> Subject: Re: [STOVES] [ethos] Bricks from Ken Goyer
>
>
> Dear Kachan, I started making ceramics test pieces and bricks using an =
> electric kiln such as potters use. At first, I fired very slowly to =
> eliminate water and burn out organic matter and then raised the =
> temperature faster. Usually I took about twelve hours to reach 1050 oC =
> or cone 03. Now I am amazed to discover that just about anything you do =
> to fire bricks works as long as you can get them to be red hot. Even if =
> you go fast. I'm sorry that I don't have the time right now to post some =
> pictures of kilns that have worked. Like I said, I am amazed, almost any =
> contained space to which you can apply heat long enough seems to work. =
> The economy of scale with bricks is in making thousands of them at once. =
> Best regards, Ken Goyer
>
> Kanchan Rai wrote:
>
> Dear ken goyer,
> thanks for providing information on clay and bricks. Could you tell me
> what kind of kiln are you using for baking bricks, how long do you bake
> at what temperature?
>
> kanchan
>
> Dear Friends, If the brick is particularly weak or won't hold
> together when fired it is probably the fault of the clay. All clays
> are not equal. Brick makers should know their clay body and how to
> adjust it. If you don't have the luxury of someone else's experience
> then making experiments is the best way to find out. Good clay has
> certain well known properties which vary depending on the use that you
> have in mind. Fortunately, our ceramics are very forgiving of much of
> the criteria that potters expect.. We don't care what color it becomes
> when fired or how thin you can turn it on a wheel. If you can make a
> ball of wet clay in your hand and it sticks together, that is a good
> sign. If you can drop the ball to the ground and it flattens but
> doesn't splatter, that is a good sign. Many other tests can be
> performed to determine it's shrinkage and firing point etc. These
> tests are described in most beginning pottery books.
> Clay can be improved by processing if necessary. One method would
> be
> to stir up a pond of clay with a beast (an animal like a horse or
> oxen). The mud that goes into suspension is decanted off to another
> pond where it is allowed to settle. This way sand and other impurities
> are removes and the smaller clay particles are hi-graded. Potters
> sometimes use a barrel with a motor driven propeller to stir up a
> slurry of clay allowing heavies to settle and then drain off the fine
> particles into another barrel. But this will not produce enough clay
> for a high production operation. The best solution is to find a good
> clean clay body sufficient for your needs for a long time.
> I don't understand why your bricks won't dry, unless it's raining
> all of the time or the humidity is extremely high. I have never had
> drying problems when using sawdust. I have had drying problems when
> using paper, newspaper, cardboard, flour, and some types of ground up
> vegetables. I like to use cement in a brick. The brick will harden in
> a day and then it can be handled and turned so more sides are exposed
> to the air. Also the brick will shrink less. I have made many
> successful bricks with no cement as well. It might take a brick a week
> to dry completely. Here in Oregon in the rainy season (most of the
> time) I like to dry bricks indoors. Often times, due to lack of
> patience, we are trying to fire wet bricks. If you proceed very slowly
> this seems to work. The brick is force dried and then the temperature
> is raised to burn out the organic matter and so on.
> The important thing is that you keep on experimenting and
> eventually
> the solution will appear. Keep asking questions too! Best of luck!
> Ken Goyer
> =20
>
> ------------------------------
>
> End of STOVES Digest - 5 Jun 2004 to 6 Jun 2004 (#2004-134)
> ***********************************************************

From hseaver at CYBERSHAMANIX.COM Mon Jun 21 08:31:00 2004
From: hseaver at CYBERSHAMANIX.COM (Harmon Seaver)
Date: Tue Aug 10 18:31:16 2004
Subject: Illuminating with LED
In-Reply-To: <3.0.32.20040618064809.00984b00@pop.btl.net>
Message-ID: <MON.21.JUN.2004.073100.0500.HSEAVER@CYBERSHAMANIX.COM>

I have one of these -- or perhaps one made by someone else, it wasn't nearly
that expensive, but I'm not sure exactly how much as my son picked it up
somewhere and gave it to me. It does work, although I think maybe the "30
seconds = 20 minutes" is a bit of an overstatement. Or maybe mine is a cheaper
version and thus not as effective??? I keep it in my camper for emergency use,
but I tend not to use flashlights much, perfering to walk around in the dark
using my natural night vision as much as possible. No poisonous snakes to step
on hereabouts. 8-)
I'll have to try to remember to look at the brand later on today.

On Fri, Jun 18, 2004 at 06:49:11AM -0600, Peter Singfield wrote:
> Dear A.D.;
>
> I to picked up on this -- see appended for text dump of their WWW site.
>
> Note this:
>
> "Only ?33.95 including postage and packing"
>
> Very expensive!! Still -- a concept easy to reverse engineer --
>
> Many years back we played with linear alternators. I still have some
> excellent papers on this subject.
>
> At the Url below one sees nice pictures of this present device. Hard to
> understand this high price!!
>
> Guess we wait for India or China to start production??
>
> Peter / Belize
>
>
> At 12:00 PM 6/18/2004 +0530, adkarve wrote:
> > Dear Stovers,
> > I got this message today, which might be of interest to some in cotext with
> >lighting with LED.
> > A.D.Karve
>
> *****************appended*************
>
> http://www.nightstartorch.com/
>
> The revolutionary NightStar? magnetic force flashlight transforms simple
> motion into light.
>
> When gently shaken, a high strength magnet passes smoothly through a wire
> coil efficiently generating electrical energy. A heavy duty capacitor
> stores the energy and delivers power to a bright white LED - just 30
> seconds of shaking provides 20 minutes of light!!
>
> Superior to a battery, the capacitor will never corrode, can be re-charged
> several hundred thousand times and will power the LED even under extreme
> hot and cold temperatures.
>
> Equally impressive, the solid state LED is practically unbreakable and has
> a rated lifetime of tens of thousands of hours; in total darkness the
> NightStar? illuminates a 12ft diameter area from a distance of 50ft. The
> state of the art components are all contained within a lightweight
> polycarbonate casing, which is waterproof, corrosion proof, and virtually
> indestructible.
>
> Only ?33.95 including postage and packing

--
Harmon Seaver
CyberShamanix
http://www.cybershamanix.com
Hoka hey!

From hseaver at CYBERSHAMANIX.COM Wed Jun 23 08:02:43 2004
From: hseaver at CYBERSHAMANIX.COM (Harmon Seaver)
Date: Tue Aug 10 18:31:16 2004
Subject: Dr. Karve's CD on charcoal making and bamboo growing
Message-ID: <WED.23.JUN.2004.070243.0500.HSEAVER@CYBERSHAMANIX.COM>

If anyone else want's a copy of this CD, they need to tell me fairly soon as
I'm going to be leaving for an extended stay in the northwoods in a couple of
weeks and won't have any way to make them -- or even get email except on trips
to town sporadically.

--
Harmon Seaver
CyberShamanix
http://www.cybershamanix.com
Hoka hey!

From snkm at BTL.NET Wed Jun 23 12:27:58 2004
From: snkm at BTL.NET (Peter Singfield)
Date: Tue Aug 10 18:31:16 2004
Subject: Illuminating with LED
Message-ID: <WED.23.JUN.2004.102758.0600.SNKM@BTL.NET>

>
>If you connect a rectifyer between the coil and the LED (and forget about
>the capacitor),you'll get a flash of light at a shake in each direction. Or
>none if the polarity is wrong.
>
>Peter Verhaart
>
>

Obviously a small switch is required -- even if just tho pieces of metal --
maybe copper plated -- that when pressed complete a circuit.

Now -- it seems to me a lot more economical and practical to use a small DC
electric motor (extremely economic) that could have a spool fitted to the
shaft to accept a "pull" string -- as in spinning a top -- etc -- with a
flywheel attached.

One short/sharp pull -- charges the capacitor!!

Or attach a small propeller/wind turbine to the shaft -- for wind charging.
Make charger separate unit.

In this area they make interesting wind turbines from used two liter
plastic water or soft drink bottles which are sold extremely cheap -- as toys!

And for the stovers -- this kind of "power-plant" should also serve purpose
of powering a small fan.

Finding a magnet -- tube -- winding coil -- is much more complicated than
using small DC motors -- off-the-shelf -- as generators.

A DC motor as used for a tape cassette drive --- probably would be over
kill!! But should supply the right voltage.

Now -- we need more info on that capacitor!!

But do believe those can be home made using wax and aluminum foil??

Certainly -- Plante style lead acid storage batteries can easily be
produced in any 3rd world country -- using the almost unlimited amount of
scrap car batteries piled up.

Plante style is the original lead acid storage batter -- exceptionally
thick pure lead plates. They can't deliver high amps -- or starting amps --
but are the best for slow discharge -- deep cycling -- and live 20 years or
more.

Would be easy to make small unit for such a proposed lighting system.

Kevin -- a list member -- is well acquainted with recycling lead acid car
batteries. But the very basic is heating lead alloys with charcoal in
reaction vessel.

Modern batteries are all based on plates being a lead alloy -- and sintered
-- etc -- very difficult to make.

Further -- Plante style batteries -- once worn out in 20 years or more --
are even easier to recycle!!

One problem would be lead acid leakage -- as these batteries must be
vented. Though probably not as much when discharging so slowly through an
LED -- as when charging.

Peter / Belize

*******************appended***********

Rechargeable batteries, also known as secondary batteries, were developed
by French scientist, Gaston Plante. The theory explored by Plante was that
primary cell batteries eventually lost all of their electricity when the
chemical reations were spent. In a rechargeable or secondary battery,
electricity from another source is introduced to reverse these chemical
reactions, restoring the battery's charge. Unfortunately, the science of
lead acid batteries had progressed hardly at all since 1859, when Gaston
Plante immersed lead plates in diluted sulfuric acid and proved current
repeatedly through them.

A good starting Url:

http://www.geocities.com/bioelectrochemistry/plante.htm

And search this term in Google for lot's more:

"plante battery"

By the way -- today -- for lead acid power plants -- the Plante battery is
still being produced and is regarded as the very best system of all.

Sometimes the more you spin technology -- the more you dig the hole you
stuck in deeper!!

For the use of lead in storage batteries -- better go back in time --

From list at SYLVA.ICUKLIVE.CO.UK Wed Jun 23 15:31:26 2004
From: list at SYLVA.ICUKLIVE.CO.UK (Andrew Heggie)
Date: Tue Aug 10 18:31:17 2004
Subject: Dr. Karve's CD on charcoal making and bamboo growing
In-Reply-To: <20040623120243.GB24646@cybershamanix.com>
Message-ID: <WED.23.JUN.2004.203126.0100.>

On Wed, 23 Jun 2004 07:02:43 -0500, Harmon Seaver wrote:

> If anyone else want's a copy of this CD, they need to tell me fairly soon as
>I'm going to be leaving for an extended stay in the northwoods in a couple of
>weeks and won't have any way to make them -- or even get email except on trips
>to town sporadically.

I have now received the CD, thanks Harmon and Dr.Karve. I can make
copies for people in UK, a quid should cover costs, if Dr. karve is
happy with this. I shall supply it as two straight .mpg files.

I have a friend who hosts a local charity site who can temporarily
loan some space so an ftp download is a possibility, if the demand is
there.

If there are any video experts out there perhaps we could see about
having it in instalments, like a multiple zip file. I suspect the cost
from a dial up would exceed the postage fee on a CD though.

AJH

From w.burroughs at VERIZON.NET Wed Jun 23 22:54:53 2004
From: w.burroughs at VERIZON.NET (Hank)
Date: Tue Aug 10 18:31:17 2004
Subject: Dr. Karve's CD on charcoal making and bamboo growing
Message-ID: <WED.23.JUN.2004.195453.0700.W.BURROUGHS@VERIZON.NET>

My son Evan and I have watched the Charcoal CD several times. Seems we get
new ideas each time! The cooking system that uses the round briquettes is
also very interesting. The CD is worth the cost if you have any kind of
"waste" biomass available.

BTW the bamboo file is also very interesting. Don't know what kinds we can
grow in Oregon but will be looking in to it.

Hank in the high desert
now home in Oregon

From list at SYLVA.ICUKLIVE.CO.UK Thu Jun 24 16:05:47 2004
From: list at SYLVA.ICUKLIVE.CO.UK (Andrew Heggie)
Date: Tue Aug 10 18:31:17 2004
Subject: Illuminating with LED
In-Reply-To: <MABBJLGAAFJBOBCKKPMGEECCDLAA.Gavin@aa3genergi.force9.co.uk>
Message-ID: <THU.24.JUN.2004.210547.0100.>

On Mon, 21 Jun 2004 00:18:19 +0100, Gavin Gulliver-Goodall wrote:

>Peter,
>To charge and discharge the capacitor you will need 2 diodes and a switch
>(one can be the LED) or better a bridge of 4 diodes so that both strokes
>will help charge the device.

The trouble with capacitors is they have very little charge capacity
at safe voltages and the biggest ones I see, 1 farad for sound
systems, cost a lot.

Getting the power out is not straightforward either because the
potential drops as it discharges. That's what's so handy about electro
chemical and thermo chemical devices, their output can be constant.

Now there is the possibility of a chemically recharged cell

http://news.bbc.co.uk/1/low/technology/3837585.stm

It's vapourware at present and probably not relevant to the needs of
those who depend on biomass for cooking, but interesting. The figures
quoted suggest a thermal to electric conversion of about 23%. This is
working on the MJ/litre of methanol at ~16, giving 31664J over
20hours.

AJH

From list at SYLVA.ICUKLIVE.CO.UK Thu Jun 24 17:07:06 2004
From: list at SYLVA.ICUKLIVE.CO.UK (Andrew Heggie)
Date: Tue Aug 10 18:31:17 2004
Subject: Dr. Karve's CD on charcoal making and bamboo growing
In-Reply-To: <008201c45996$a3baa0a0$6601a8c0@domain.actdsltmp>
Message-ID: <THU.24.JUN.2004.220706.0100.>

On Wed, 23 Jun 2004 19:54:53 -0700, Hank wrote:

>My son Evan and I have watched the Charcoal CD several times. Seems we get
>new ideas each time! The cooking system that uses the round briquettes is
>also very interesting. The CD is worth the cost if you have any kind of
>"waste" biomass available.

I agree Hank, I have always believed that the western world could make
use of similar techniques to its benefit.

At struck me that Tom Reed's recent post about making fuel from waste
could take note of the pragmatic approach used by ELK and Dr Karve.

AJH

From psanders at ILSTU.EDU Thu Jun 24 19:07:44 2004
From: psanders at ILSTU.EDU (Paul S. Anderson)
Date: Tue Aug 10 18:31:17 2004
Subject: Dr. Karve's CD on charcoal making and bamboo growing
In-Reply-To: <p1dmd0l41qptqc28klpgfr4emnva5g7kin@4ax.com>
Message-ID: <THU.24.JUN.2004.180744.0500.PSANDERS@ILSTU.EDU>

At 10:07 PM 6/24/04 +0100, Andrew Heggie wrote:

>At struck me that Tom Reed's recent post about making fuel from waste
>could take note of the pragmatic approach used by ELK and Dr Karve.

I must disagree. Somewhere between 60% and 80% (depending on biomass) of
the heat / energy value is given up (thrown away) when making the charcoal
briquettes from waste biomass. When that biomass is ABUNDANT, then the ELK
and Karve systems can be appropriate. But Reed is trying to get the most
energy from a limited supply of waste materials (including packaging for
camp supplies) and with almost immediate usage (not much transport or
storage issues).

Keeping with the Subject of these messages, the issues of bamboo and other
surplus biomass as fuels should be considered in relation to TOTAL energy
and CHAR energy. The reduction of weight for char versus the full energy
with full (dried, chipped) biomass needs further study. The ACTUAL
practice especially in urban areas that PREFER char briquettes is mainly
based on the "cleanliness" of the char burning. In some cases, there are
laws against burning the raw biomass, but burning char is allowed. BUT,
when the stoves are found that can take the full biomass (but chopped and
dried to be appropriate for the stove) and burn it with the same
cleanliness as charcoal, THEN we might find it economically much better to
not go to the intermediary step of the char production.

And certainly there are enough diverse cultures and environments that
simultaneously some places will
1. stay with rough wood/biomass
2. stay with char
3. go with moderately processed full biomass in stoves that actually are
clean burning.

Paul

From elk at WANANCHI.COM Fri Jun 25 02:20:54 2004
From: elk at WANANCHI.COM (Elsen Karstad)
Date: Tue Aug 10 18:31:17 2004
Subject: Fw: [hedon news] Stoves and Carbon Trading Research Project
Announcement
Message-ID: <FRI.25.JUN.2004.092054.0300.ELK@WANANCHI.COM>

This Just in from the HEDON list.

elk
--------------------------------
Elsen L. Karstad
elk@wananchi.com
www.chardust.com
Nairobi, Kenya

----- Original Message -----
From: "Jonathan Avis" <jonathan.avis@eci.ox.ac.uk>
To: <news@hedon.info>
Sent: Thursday, June 24, 2004 5:38 PM
Subject: [hedon news] Stoves and Carbon Trading Research Project
Announcement

> Carbon trading under the Clean Development Mechanism could present a
> valuable new opportunity to fund Improved Cooking Stove (ICS)
> projects. This could bring substantial benefits, not only in reducing
> emissions of greenhouse gases, but also in significant sustainable
> development benefits of ICS such as reduced indoor air pollution and
> less time spent gathering fuelwood.
>
> I am currently undertaking a dissertation thesis, researching whether
> Carbon Trading could be used to promote and fund ICS programmes. If
> you have any interests in this field, please contact me on
> jonathan.avis@eci.ox.ac.uk - I am particularly looking for data on
> greenhouse gas emissions from ICS, methods of determining baselines,
> monitoring of ICS projects, and methods of successful dissemination
> and spreading of ICS.
>
> Please see
>
>
www.hedon.info/goto.php/ImprovedCookingStovesAndTheCleanDevelopmentMechanism
>
> for full information.
>
> Jonathan Avis
> MSc Environmental Change and Management
> Environmental Change Institute, University of Oxford
> 5 South Parks Road, Oxford, OX1 3UB
>
> -----------------------------------------------------------------------
>
> jonathan.avis@linacre.ox.ac.uk
> tel. 07830158 589
>
> About me: www.hedon.info/goto.php/User:JonathanAvis
>
>
>
www.hedon.info/goto.php/ImprovedCookingStovesAndTheCleanDevelopmentMechanism
>
>
>
>
>
>
>
> --
> Please forward this email to any of your colleagues or business partners.
> We rely on users to spread the word about HEDON to the entire Household
> Energy community. In addition, please consider adding your own material
> to the HEDON web page resources. This is a simple process and can go a
> long way towards generating publicity for your activites among a select
> audience of professionals.
>
> For more information about HEDON visit: http://www.hedon.info
>
> You can change your subscription to the HEDON email list (as well as other
> relevant email lists) - for example unsubscribe - through the online HEDON
> User Centre. Visit www.hedon.info and login using your email address and
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> Energy Network. If you have questions or concerns about this please email
> us.
>
> Please direct any queries to Grant Ballard-Tremeer <grant@ecoharmony.com>
>
>

From hseaver at CYBERSHAMANIX.COM Fri Jun 25 07:46:23 2004
From: hseaver at CYBERSHAMANIX.COM (Harmon Seaver)
Date: Tue Aug 10 18:31:17 2004
Subject: Dr. Karve's CD on charcoal making and bamboo growing
In-Reply-To: <suljd0duk6r8e638jtkmsrln1eil2l4ss1@4ax.com>
Message-ID: <FRI.25.JUN.2004.064623.0500.HSEAVER@CYBERSHAMANIX.COM>

On Wed, Jun 23, 2004 at 08:31:26PM +0100, Andrew Heggie wrote:
> On Wed, 23 Jun 2004 07:02:43 -0500, Harmon Seaver wrote:
>
> > If anyone else want's a copy of this CD, they need to tell me fairly soon as
> >I'm going to be leaving for an extended stay in the northwoods in a couple of
> >weeks and won't have any way to make them -- or even get email except on trips
> >to town sporadically.
>
>
> I have now received the CD, thanks Harmon and Dr.Karve. I can make
> copies for people in UK, a quid should cover costs, if Dr. karve is
> happy with this. I shall supply it as two straight .mpg files.
>
> I have a friend who hosts a local charity site who can temporarily
> loan some space so an ftp download is a possibility, if the demand is
> there.
>
> If there are any video experts out there perhaps we could see about
> having it in instalments, like a multiple zip file. I suspect the cost
> from a dial up would exceed the postage fee on a CD though.

My son, who plays around with video a lot, tells me that there is software
that will reduce the size tremendously and without reducing the picture/sound
quality, however it would also require people to download and install a special
codec and player, both also very small. But unless it were made a very simple
operation, like a batch file that people could just click on that would do it
all for them, I think a lot of people wouldn't be able to get it to work.
I haven't had time to look into that, and won't be able to for quite awhile,
but I can ask him for the instructions if your interested in trying that.

--
Harmon Seaver
CyberShamanix
http://www.cybershamanix.com
Hoka hey!

From list at SYLVA.ICUKLIVE.CO.UK Fri Jun 25 09:24:42 2004
From: list at SYLVA.ICUKLIVE.CO.UK (Andrew Heggie)
Date: Tue Aug 10 18:31:17 2004
Subject: Dr. Karve's CD on charcoal making and bamboo growing
In-Reply-To: <4.3.1.2.20040624175007.01aa8f00@mail.ilstu.edu>
Message-ID: <FRI.25.JUN.2004.142442.0100.>

On Thu, 24 Jun 2004 18:07:44 -0500, Paul S. Anderson wrote:

Nothing like a bit of disagreement to provoke an enlightening
discussion ;-)

> Somewhere between 60% and 80% (depending on biomass) of
>the heat / energy value is given up (thrown away) when making the charcoal
>briquettes from waste biomass.

Not necessarily, the heat need not be wasted, it's a matter of finding
something that can use it.

> When that biomass is ABUNDANT, then the ELK
>and Karve systems can be appropriate.

Yes, I said it was pragmatic, in Karve's case the sugar cane trash
would be burned to waste anyway, in ELK's case the sawdust would rot
(a mixture of anaerobic and aerobic composting/digestion). In both
cases reducing it to a char product facilitates the briquetting (the
other option of densification implying both a large capital spend and
sophisticated power use) and increases the energy density whilst
giving a burning characteristic the customer wants.

> But Reed is trying to get the most
>energy from a limited supply of waste materials (including packaging for
>camp supplies) and with almost immediate usage (not much transport or
>storage issues).

In fact tom Reed did not specify his waste, I assumed it more to be
the high moisture content chiefly vegetable waste. Aside from Tom's
particular client's requirement it is not much different from
municipal rubbish disposal. The standard option seems to be bury it,
next burn it and finally sort it out and deal will the various
fractions more appropriately. Packaging, in the form of cardboard and
simple plastics, could contribute a lot of extra energy, as long as
the ash content did not get too high (like with glossy magazines).

Now in UK the putrescible bits can be burned, composted or digested.
Composting is the easiest hoop to jump through but yields a low value
bulky product.

Anaerobic digestion is used a lot, with the biogas being used for
power in sewerage plants and from landfill, rather than flared.

All these techniques need large structures and long retention times. A
sophisticated pyrolysis plant is fast, compact, energy efficient,
portable plus the output is a high added value fuel. Change the size
of briquettes produced from the 38 gramme pillow briquette or the
extruded "meat mincer" briquette down to an 8mm pellet with a coating
and you have a product that can be metered into a controllable cooking
device.

>
>Keeping with the Subject of these messages, the issues of bamboo and other
>surplus biomass as fuels should be considered in relation to TOTAL energy
>and CHAR energy. The reduction of weight for char versus the full energy
>with full (dried, chipped) biomass needs further study. The ACTUAL
>practice especially in urban areas that PREFER char briquettes is mainly
>based on the "cleanliness" of the char burning. In some cases, there are
>laws against burning the raw biomass, but burning char is allowed. BUT,
>when the stoves are found that can take the full biomass (but chopped and
>dried to be appropriate for the stove) and burn it with the same
>cleanliness as charcoal, THEN we might find it economically much better to
>not go to the intermediary step of the char production.

I agree with this but feel you miss the point that char making can be
clean and the energy balance can favour a pyrolised product when using
biomass at around 50% mc.
>
>And certainly there are enough diverse cultures and environments that
>simultaneously some places will
>1. stay with rough wood/biomass
>2. stay with char

OK
>3. go with moderately processed full biomass in stoves that actually are
>clean burning.

This must be the area where Richard Stanley sits differing from Dr.
Karve and ELK in that his biomass has undergone only slight rotting
and then drying.

It looks to me that in between there is a grade of charcoal product
that is made in the right part of the temperature curve to react fast
enough (i.e. some internal feedback of heat in the "autopyrolysis
region) and with sufficient enthalpy in the offgas to "prepare" the
rawstock for pyrolysis.

AJH

From rstanley at LEGACYFOUND.ORG Fri Jun 25 14:22:17 2004
From: rstanley at LEGACYFOUND.ORG (Richard Stanley)
Date: Tue Aug 10 18:31:17 2004
Subject: Dr. Karve's CD on charcoal making and bamboo growing
In-Reply-To: <4.3.1.2.20040624175007.01aa8f00@mail.ilstu.edu>
Message-ID: <FRI.25.JUN.2004.202217.0200.RSTANLEY@LEGACYFOUND.ORG>

Paul AD, and other stovers,

When we were fced with the problem of decomposing resistant biomass
such as bamboo leaves for the wet low pressure briquetting process,
local exerrience in Mangochi district Malawi came up with the insight
that certain grasses when mixed with the bamboo will tend to break it
down rapidly. The same was discovered Miumbuni women's group in Makweni
District Kenya and by a produciton group we trained in the township of
Qquea, Cusco district Peru both were faced with the need for efficient
decomposition of eucalyptus leaves.
I agree with Paul that the Karve Eklk solution applies to areas of
abundant biomass but not necessarily to the more stressed areas. While
a wet process briquette may have only 75% the heat value of charred
material, not a calorie of its inherent energy potential is wasted in
its preparation.

Richard Stanley

. But I offer little new here eh ?

Paul S. Anderson wrote:

> At 10:07 PM 6/24/04 +0100, Andrew Heggie wrote:
>
>> At struck me that Tom Reed's recent post about making fuel from waste
>> could take note of the pragmatic approach used by ELK and Dr Karve.
>
>
> I must disagree. Somewhere between 60% and 80% (depending on biomass) of
> the heat / energy value is given up (thrown away) when making the
> charcoal
> briquettes from waste biomass. When that biomass is ABUNDANT, then
> the ELK
> and Karve systems can be appropriate. But Reed is trying to get the most
> energy from a limited supply of waste materials (including packaging for
> camp supplies) and with almost immediate usage (not much transport or
> storage issues).
>
> Keeping with the Subject of these messages, the issues of bamboo and
> other
> surplus biomass as fuels should be considered in relation to TOTAL energy
> and CHAR energy. The reduction of weight for char versus the full energy
> with full (dried, chipped) biomass needs further study. The ACTUAL
> practice especially in urban areas that PREFER char briquettes is mainly
> based on the "cleanliness" of the char burning. In some cases, there are
> laws against burning the raw biomass, but burning char is allowed. BUT,
> when the stoves are found that can take the full biomass (but chopped and
> dried to be appropriate for the stove) and burn it with the same
> cleanliness as charcoal, THEN we might find it economically much
> better to
> not go to the intermediary step of the char production.
>
> And certainly there are enough diverse cultures and environments that
> simultaneously some places will
> 1. stay with rough wood/biomass
> 2. stay with char
> 3. go with moderately processed full biomass in stoves that actually are
> clean burning.
>
> Paul
>
> Paul S. Anderson, Ph.D.
> Dept of Geography - Geology (Box 4400), Illinois State University
> Normal, IL 61790-4400 Voice: 309-438-7360; FAX: 309-438-5310
> E-mail: psanders@ilstu.edu - Internet items: www.ilstu.edu/~psanders
> NOTE: Retired from teaching. Active in Stoves development.
> For fastest contact, please call home phone: 309-452-7072
>
>
>

From list at SYLVA.ICUKLIVE.CO.UK Fri Jun 25 15:17:45 2004
From: list at SYLVA.ICUKLIVE.CO.UK (Andrew Heggie)
Date: Tue Aug 10 18:31:17 2004
Subject: Dr. Karve's CD on charcoal making and bamboo growing
In-Reply-To: <suljd0duk6r8e638jtkmsrln1eil2l4ss1@4ax.com>
Message-ID: <FRI.25.JUN.2004.201745.0100.>

On Wed, 23 Jun 2004 20:31:26 +0100, Andrew Heggie wrote:

>I have now received the CD, thanks Harmon and Dr.Karve. I can make
>copies for people in UK, a quid should cover costs, if Dr. karve is
>happy with this. I shall supply it as two straight .mpg files.

I have received Dr. Karve's approval for this.
>
>I have a friend who hosts a local charity site who can temporarily
>loan some space so an ftp download is a possibility, if the demand is
>there.

Thanks to an offer from a list member I have now managed this, it took
about 2 hours for each file! He is away for two weeks now so I shall
be unsure if he manages to download them or whether he will make them
available via anonymous ftp, I will await his return but for anyone
with un metered broadband it seems to be a painless method.

AJH

From stephen.gitonga at UNDP.ORG Fri Jun 25 16:43:12 2004
From: stephen.gitonga at UNDP.ORG (Stephen Gitonga)
Date: Tue Aug 10 18:31:17 2004
Subject: Fw: [hedon news] Stoves and Carbon Trading Research Project
Announcement
In-Reply-To: <003101c45a7d$a921e840$c348083e@toshibauser>
Message-ID: <FRI.25.JUN.2004.164312.0400.STEPHEN.GITONGA@UNDP.ORG>

Dear Stovers

The report at
http://www.iesd.dmu.ac.uk/contract_research/publications/kb1.pdf has some
insights on potential opportunities and constraints for Stoves and Carbon
Trading based on studies in Kenya, Tanzania and Ghana. There are good
examples of stoves programmes as it relates to baselines, bundling of
projects, carbon trading, UNFCCC guidelines and CDM.

Cheers

Stephen

-----Original Message-----
From: The Stoves Discussion List [mailto:STOVES@LISTSERV.REPP.ORG]On Behalf
Of Elsen Karstad
Sent: 25 June 2004 02:21
To: STOVES@LISTSERV.REPP.ORG
Subject: [STOVES] Fw: [hedon news] Stoves and Carbon Trading Research
Project Announcement

This Just in from the HEDON list.

elk
--------------------------------
Elsen L. Karstad
elk@wananchi.com
www.chardust.com
Nairobi, Kenya

From paul.akangah at OSGH.ORG Sun Jun 27 06:12:20 2004
From: paul.akangah at OSGH.ORG (Paul Akangah)
Date: Tue Aug 10 18:31:17 2004
Subject: Dr. Karve's CD on charcoal making and bamboo growing
Message-ID: <SUN.27.JUN.2004.061220.0400.PAUL.AKANGAH@OSGH.ORG>

Hello Sir,

Please I will like a copy of Dr. Karve's CD on Charcoal making and bamboo
growing.

Regards
Paul Akangah

From jeff.forssell at CFL.SE Mon Jun 28 08:34:29 2004
From: jeff.forssell at CFL.SE (Jeff Forssell)
Date: Tue Aug 10 18:31:17 2004
Subject: SV: [STOVES] Dr. Karve's CD-video compression
Message-ID: <MON.28.JUN.2004.143429.0200.JEFF.FORSSELL@CFL.SE>

> My son, who plays around with video a lot, tells me that there is software
>that will reduce the size tremendously and without reducing the picture/sound
>quality, however it would also require people to download and install a special
>codec and player, both also very small. But unless it were made a very simple
>operation, like a batch file that people could just click on that would do it
>all for them, I think a lot of people wouldn't be able to get it to work.

Usually you don't need a special videoplayer. The MS Media Player that most people have can usually handle most codecs. Most machines probably already have eg. the INDEO codecs installed. Even they can give a big compression (it depends on the content how much).

Maybe a snippet of the video could be compressed with a common Codec. Then the interested party could see if his/her machine could handle it directly, without intalling another codec..

Otherwise the idea of an installation bundle (like a a ZIP file with a suitble install.bat) is good, for those whose machines don't handle it. (How many stovers use MAC?)

Jeff Forssell
SWEDISH AGENCY FOR FLEXIBLE LEARNING (CFL)
Box 3024
SE-871 03 H?RN?SAND /Sweden
http://www.cfl.se/?sid=60
+46(0)611-55 79 48 (Work) +46(0)611-55 79 80 (Fax Work)
+46(0)611-22 1 44 (Home) ( mobil: 070- 35 80 306; [070-4091514])
residence:
Gamla Karlebyv?gen 14 / SE-871 33 H?rn?sand /Sweden
e-mail: every workday: jeff.forssell@cfl.se
(travel, visiting: jeff_forssell@hotmail.com & MS Messenger)
Personal homepage: http://www.torget.se/users/i/iluhya/index.htm
My village technology page: http://home.bip.net/jeff.forssell
Instant messengers Odigo 792701 (ICQ: 55800587; NM/MS M use hotmail address)

From solar1 at ZUPER.NET Sun Jun 27 09:34:50 2004
From: solar1 at ZUPER.NET (Fundacion Centro para el Desarrollo con Energia Solar)
Date: Tue Aug 10 18:31:17 2004
Subject: SV: [STOVES] Dr. Karve's CD-video compression
In-Reply-To: <BA468CE631F86A4D831FCBD4EB1C692C0ACDCC@floyd.cfl.local>
Message-ID: <SUN.27.JUN.2004.093450.0400.SOLAR1@ZUPER.NET>

We use Mac
in a previous message, Jeff Forssell on 6/28/04 08:34 at
jeff.forssell@CFL.SE wrote:

>> My son, who plays around with video a lot, tells me that there is software
>> that will reduce the size tremendously and without reducing the picture/sound
>> quality, however it would also require people to download and install a
>> special
>> codec and player, both also very small. But unless it were made a very simple
>> operation, like a batch file that people could just click on that would do it
>> all for them, I think a lot of people wouldn't be able to get it to work.
>
> Usually you don't need a special videoplayer. The MS Media Player that most
> people have can usually handle most codecs. Most machines probably already
> have eg. the INDEO codecs installed. Even they can give a big compression (it
> depends on the content how much).
>
> Maybe a snippet of the video could be compressed with a common Codec. Then the
> interested party could see if his/her machine could handle it directly,
> without intalling another codec..
>
> Otherwise the idea of an installation bundle (like a a ZIP file with a suitble
> install.bat) is good, for those whose machines don't handle it. (How many
> stovers use MAC?)
>
>
> Jeff Forssell
> SWEDISH AGENCY FOR FLEXIBLE LEARNING (CFL)
> Box 3024
> SE-871 03 H?RN?SAND /Sweden
> http://www.cfl.se/?sid=60
> +46(0)611-55 79 48 (Work) +46(0)611-55 79 80 (Fax Work)
> +46(0)611-22 1 44 (Home) ( mobil: 070- 35 80 306; [070-4091514])
> residence:
> Gamla Karlebyv?gen 14 / SE-871 33 H?rn?sand /Sweden
> e-mail: every workday: jeff.forssell@cfl.se
> (travel, visiting: jeff_forssell@hotmail.com & MS Messenger)
> Personal homepage: http://www.torget.se/users/i/iluhya/index.htm
> My village technology page: http://home.bip.net/jeff.forssell
> Instant messengers Odigo 792701 (ICQ: 55800587; NM/MS M use hotmail address)
>

David Whitfield V.
Director Ejecutivo Fundaci?n CEDESOL.
Centro de Desarrollo en Energ?a Solar.
Av. Petrolera Km. 0 Cochabamba ? Bolivia.
Tel: (591 ? 4) 4258093.
Cel: (591) 77424269 m?bil.
La Paz - Bolivia.
Tel: (591 - 2) 2414882.

solar1 at zuper.net.

From tombreed at COMCAST.NET Tue Jun 29 09:20:21 2004
From: tombreed at COMCAST.NET (TBReed)
Date: Tue Aug 10 18:31:17 2004
Subject: Bioconversion is ...?
Message-ID: <TUE.29.JUN.2004.072021.0600.TOMBREED@COMCAST.NET>

Dear Paul:

Glad to have you on Bioconversion. I do Gasification.

What do you see as the area of Bioconversion over and above Stoves,
Gasification, Ethanol, Digestion etc.? It would be nice if you could draw
us a map.

Thanks,

TOM REED GASIFICATION
----- Original Message -----
From: "Paul Harris" <paul.harris@ADELAIDE.EDU.AU>
To: <BIOCONVERSION@LISTSERV.REPP.ORG>
Sent: Monday, June 28, 2004 10:56 PM
Subject: [BIOC] G'day

> G'day,
>
> Having looked at the posts for this year I see that not many messages are
> received, because not many are sent.
>
> I have just joined this list (I moderate the anaerobic digestion list) to
> see what goes on in the wider world and as I have an increasing
involvement
> in renewable energy.
>
> In my other life I am a lecturer at The Univerity of Adelaide, trying to
> teach agricultural engineering to agriculture students.
>
> All the best,
> HOOROO
> Paul Harris,
> Roseworthy, South Australia

From psanders at ILSTU.EDU Tue Jun 29 18:43:22 2004
From: psanders at ILSTU.EDU (Paul S. Anderson)
Date: Tue Aug 10 18:31:17 2004
Subject: Dr. Karve's CD on charcoal making and bamboo growing
In-Reply-To: <5dtnd0hpnurithc4b0vdvsaunbcg6r5fbd@4ax.com>
Message-ID: <TUE.29.JUN.2004.174322.0500.PSANDERS@ILSTU.EDU>

At 02:24 PM 6/25/04 +0100, Andrew Heggie wrote:
>(with lots of snips)
>Nothing like a bit of disagreement to provoke an enlightening
>discussion ;-)
>(snip)
>I agree with this [about bamboo and char] but feel you miss the point that
>char making can be
>clean and the energy balance can favour a pyrolised product when using
>biomass at around 50% mc.
>(snip)
>This must be the area where Richard Stanley sits differing from Dr.
>Karve and ELK in that his biomass has undergone only slight rotting
>and then drying.
>(snip)
>It looks to me that in between there is a grade of charcoal product
>that is made in the right part of the temperature curve to react fast
>enough (i.e. some internal feedback of heat in the "autopyrolysis
>region) and with sufficient enthalpy in the offgas to "prepare" the
>rawstock for pyrolysis.

Andrew has interesting comments. just to mention 50% mc (moisture content,
right?) as being possibly viable does change the picture. and his last
paragraph lays open the question of some processing of "junk" biomass (such
as bamboo in extensive areas) that there is a balance generated and needed
that would simplify the whole process and give good benefits to everyone.

But has anyone found that balance point? and can it be put into practice?

Worth thinking about.

Paul

From snkm at BTL.NET Wed Jun 30 15:33:20 2004
From: snkm at BTL.NET (Peter Singfield)
Date: Tue Aug 10 18:31:17 2004
Subject: Bioconversion is ...?
Message-ID: <WED.30.JUN.2004.133320.0600.SNKM@BTL.NET>

At 07:20 AM 6/29/2004 -0600, TBReed wrote:
>Dear Paul:
>
>Glad to have you on Bioconversion. I do Gasification.
>
>What do you see as the area of Bioconversion over and above Stoves,
>Gasification, Ethanol, Digestion etc.? It would be nice if you could draw
>us a map.
>
>Thanks,
>
>TOM REED

Then this should be of interest (Peter in Belize)

June 28, 2004

Note to Journalists: A publication-quality file photograph of Nancy Ho
is available at http://ftp.purdue.edu/pub/uns/+2004/ho.ethanol.jpg.
Writer Emil Venere will be out of town from July 1-9. During that
period, reporters can contact public affairs representative Jeanine
Phipps for assistance at (765) 494-0748,
jsphipps@purdueresearchfoundation.org.

PURDUE YEAST MAKES ETHANOL FROM AGRICULTURAL WASTE MORE EFFECTIVELY

WEST LAFAYETTE, Ind. - A strain of yeast developed at Purdue University
more effectively makes ethanol from agricultural residues that would
otherwise be discarded or used as animal feed, and the first license
for the yeast has been issued to the biotechnology company Iogen Corp.

Purdue's genetically altered yeast allows about 40 percent more ethanol
to be made from sugars derived from agricultural residues, such as corn
stalks and wheat straw, compared with "wild-type" yeasts that occur in
nature.

The agricultural residues are primarily made up of cellulose and
"hemicellulose," which are known as cellulosic materials. Unlike
traditional ethanol feedstocks, such as corn kernels, the cellulosic
materials contain two major sugars, glucose and xylose, which cannot
both be fermented into ethanol by natural Saccharomyces yeast, the
microorganism used by industry to produce ethanol, said Nancy Ho, a
senior research scientist and leader of the molecular genetics group in
Purdue's Laboratory of Renewable Resources Engineering, or LORRE.

Iogen specializes in producing ethanol from cellulosic material.

A team led by Ho developed the more efficient yeast during the 1980s
and 1990s. Conventional yeast can ferment glucose to ethanol, but it
cannot ferment xylose. Xylose makes up about 30 percent of the sugar
from agricultural residues, and the inability to ferment xylose would
represent a major loss of ethanol yield, Ho said.

The Purdue researchers altered the genetic structure of the yeast so
that it now contains three additional genes that make it possible to
simultaneously convert glucose and xylose to ethanol. The ability to
ferment xylose increases the yield of ethanol from straw by about 40
percent. Being able to simultaneously ferment glucose and xylose is
important because both sugars are found together in agricultural
residues, Ho said.

"It would cost too much money to separate the two sugars before
proceeding with fermentation to ethanol, so being able to ferment both
sugars together to ethanol is critical," she said. "To be more cost
competitive with gasoline, the two sugars have to be converted together
to ethanol.

"Until we developed our yeast, no suitable microorganism could convert
these two sugars together."

Iogen has obtained a non-exclusive license from the Purdue Research
Foundation for the yeast and related patents. Its Ottawa, Canada,
demonstration facility is the first plant in the world to produce
ethanol from cellulosic materials. Iogen is using the Purdue yeast to
produce ethanol from the sugars the company derives from wheat straw.

"We have confirmed that Purdue's recombinant glucose- and
xylose-fermenting yeast is the most effective microorganism available
for the production of ethanol from cellulosic materials," said Jeffrey
S. Tolan, senior research scientist for Iogen. "The ethanol yield and
productivity from the Purdue yeast in our plant matches that obtained
by Dr. Ho's group in the lab at Purdue. The Purdue yeast is also easy
to work with and is favored by our plant operators because of this."

The ethanol made in Iogen's plant is blended into gasoline at the
Petro-Canada refinery in Montreal. Cars use the ethanol-gasoline blend
without any modifications; typically, drivers are not even aware of the
presence of the ethanol, except for the label on the gas pump. The
Ottawa plant represents the latest step toward Iogen's goal of making
ethanol from cellulosic materials widely available as a fuel, Tolan
said.

In Iogen's process, about two-thirds of the straw is converted to
ethanol, with a yield of about 75 gallons of ethanol per ton of straw.
Most of the remaining one-third of the agricultural residue, which
cannot be fermented, is burned to generate power to run the plant, and
there is little waste or use of fossil fuels, he said.

"The use of cellulose ethanol offers advantages to the environment that
are not obtained with other transportation fuels that are available,"
Tolan said.

Also known as ethyl alcohol, ethanol can be used as fuel by itself or
blended with gasoline. The Purdue yeast is used in combination with
other technologies under development that first convert agricultural
materials to xylose and glucose, said Purdue's Michael Ladisch,
Distinguished Professor of Agricultural and Biological Engineering and
director of LORRE.

"Iogen's efforts are beneficial to companies in Indiana and elsewhere
in the United States by providing an industrial test bed for the
fermentation part of the cellulose conversion technology, hence
speeding its development for uses on a range of crops and crop residues
once the other technologies, including preprocessing of the cellulosic
materials and converting these materials to sugars, are developed and
proven in the industry," Ladisch said.

Ethanol is environmentally friendly and a cleaner fuel than gasoline,
he said.

"The carbon dioxide that is generated from burning ethanol is recycled
back into plant material because plants incorporate CO2 into cellulose
as part of the photosynthesis cycle," Ladisch said. "This reduces the
net generation of the greenhouse gas since part of it is recycled."

Ethanol currently is produced when yeast ferments glucose and related
hexose - or six-carbon sugars in food crops such as cane sugar, corn
and other starch-rich grains. However, Ho said, because these crops are
expensive and in relatively limited supply, they can't yield sufficient
amounts of ethanol for transportation needs.

Cellulosic materials represent an opportunity to address this problem,
she said. Cellulosic materials cost only about half as much as corn per
ton but are more difficult than corn to convert to ethanol. Part of the
difficulty is the fermentation to ethanol of the xylose, which is a
five-carbon sugar. This sugar is not naturally fermented by yeast or
other microorganisms.

"Corn-based ethanol production in the United States currently is about
3 billion gallons per year," Ho said. "According to conservative
estimates, 30 percent of the residue left behind in the cornfield after
harvest could produce another 4 billion to 5 billion gallons annually.

"The use of cellulosic materials also could open up new markets for
crops such as grasses, which can be grown on marginal lands, creating
jobs and providing more energy independence."

An added advantage of yeast strains developed by Ho is that they are
based on environmentally safe Saccharomyces yeast, which has been used
for centuries to make wine and bread and is the only microorganism used
by industry for large-scale ethanol production from glucose.

Ho has worked for 20 years to produce and perfect a yeast that can
effectively convert more of the sugars in plant matter - corn stalks,
tree leaves, wood chips, grass clippings, and even cardboard - into
ethanol.

"Ethanol produced from cellulosic materials is an ideal, domestically
available fuel," Ho said.

In 1993, Ho's group became the first in the world to produce a
genetically engineered Saccharomyces yeast that can effectively ferment
both glucose and xylose.

Ho's research has been funded by the U.S. Department of Agriculture,
the Department of Energy, the Consortium for Plant Biotechnology
Research Inc., the U.S. Environmental Protection Agency and industry
sources.

Ho holds a doctoral degree in molecular biology from Purdue, a master's
degree in organic chemistry from Temple University and a bachelor's
degree in chemical engineering from the National Taiwan University.

Writer: Emil Venere, (765) 494-4709, venere@purdue.edu

Sources: Nancy Ho, (765) 494-7046, nwyho@ecn.purdue.edu

Michael Ladisch, (765)494-7022, ladisch@purdue.edu

Jeffrey S. Tolan, (613) 733 9830 (Ext. 3407), jefft@iogen.ca

Simran Trana, Purdue Research Foundation licensing contact, (765)
494-6725, strana@purdueresearchfoundation.org

Related Web sites:

Laboratory of Renewable Resources Engineering:
https://engineering.purdue.edu/IIES/LORRE/

Iogen Corp.: http://www.iogen.ca

PHOTO CAPTION:

A genetically engineered form of yeast developed at Purdue's Laboratory
of Renewable Resources Engineering can produce about 40 percent more
ethanol from sugars derived from agricultural residues that would
otherwise be discarded or used as animal feed. Nancy Ho, a senior
research scientist and leader of the lab's molecular genetics group,
holds cultures of the new yeast strain (in the Petri dish) and a sample
of ethanol. (Purdue News Service file photo/David Umberger)

A publication-quality photo is available at
http://ftp.purdue.edu/pub/uns/+2004/ho.ethanol.jpg

------------------------
Purdue University News Service
400 Centennial Mall Drive Room 324
West Lafayette, IN 47906-2016
purduenews@purdue.edu
Office (765) 494-2096
Fax (765) 494-0401

From crispin at NEWDAWN.SZ Wed Jun 30 16:36:30 2004
From: crispin at NEWDAWN.SZ (Crispin Pemberton-Pigott)
Date: Tue Aug 10 18:31:17 2004
Subject: Testing with a CO + CO2 Meter
Message-ID: <WED.30.JUN.2004.223630.0200.>

Dear Stovers and Testers

I have been keeping my nose to the grindstone here in Swaziland and
practising collecting measurements - something about which I know little
other than what I have read, mostly on this list. I found that I was
confused by certain numbers, ratios and claims for different stoves.

Having Tami around is a blessing because she thinks about these things
and does much to boot. After a number of emails passed back and forth
between the members of this mutual appreciation club, I am venturing out
into the sunshine to start making reports on useful aspects of my work.
I am writing this for all the people who have never used fancy equipment
to measure what is going on in a stove - I have just started too!

First, something that I was confused about: I have heard different
numbers quoted for the 'amount of carbon-monoxide (CO) a stove produces'
and while it was illogical in certain respects, it sounds simple and
thus a good method of evaluating the effectiveness of combustion and the
usefulness of the stove design or application.

There are two places where CO is important: in the stove, and in the
room. If there is a lot of CO in parts per million (ppm) in the room,
it is bad, but if it is in the stove (I will say 'in the chimney'), it
is not necessarily bad. It depends on how much CO2 there is mixed with
it. This I didn't understand initially. I thought it was analogous to a
heat transfer efficiency - a better number means a better stove.

CO2 in the chimney is evidence of the combustion of a carbon-containing
fuel in the combustion chamber. The contentration of that CO2 in ppm is
irrelevant. If you burn carbonaceous fuel there will be CO2 in the
chimney at some concentration or other. If you let in a LOT of excess
air, the CO2 will be diluted so there is no value in comparing the CO2
concentrations of different stoves. Unless you know exactly how much
unneeded air is passing through the stove, the CO2 concentration is just
a number. For example, if you have a stove and measure 5.5% CO2 in the
chimney, it only means that 94.5% of the gases are something else. It
does not tell anything useful about the fire or the stove.

CO in the chimney is evidence of incomplete combustion of a
carbon-containing fuel in the combustion chamber. Again. The
concentration of the CO in the chimney is not a meaningful figure.
There is nothing you can decide about one stove that has 650 ppm CO in
the chimney and another that has 225 ppm CO using that figure on its
own. The one with the lower figure might be drafting large amounts of
air through the stove and diluting the CO.

What is very useful is to know how much of the carbon that is being
burned is emerging from the combustion chamber as CO and how much as
CO2. If the CO is high and the CO2 is low, this indicates incomplete
combustion. For example when lighting a coal fire with newspaper and
wood, I got CO figures of as much as 15% of the CO2 level. This is
expressed by my meter as a proportion of CO to CO2, for example the CO2
might be 6.23% of the chimney gases and the CO level might be 0.023 of
that. The South African Bureau of Standards (SABS) wishes CO from
paraffin stoves to be at a 0.02 of the CO2 level.

Collecting the gases with a hood and extracting them and measuring the
absolute CO level in ppm tells you almost nothing unless you are
measuring other things as well. If the exact dilution is not known, the
figure has no value. It is the RATIO that is important as it tells us
what the efficiency and completeness of combustion is.

The CO level in a room in ppm is a totally different matter altogether.
The health risk from exposure to CO from breathing smoke in a room is
given a danger rating based on the concentration and the exposure time.
Briefly, you can live in 9 ppm, get by for 8 hours at 50 ppm and you
have to leave the room at 100 ppm. At 1000 ppm you will not live more
than a few minutes.

All this CO in a room story bears no direct relationship to the stove CO
numbers because you might be burning a large clean fire or a small dirty
fire and the result for the room would be the same. An example of this
would be burning a rather large amount of wood in a room in a fire with
an average 3% (0.03) CO level or exactly 1/2 as much charcoal at a 6%
(0.06) CO level. One might say the charcoal is twice as polluting. It
is no more polluting if the amount of fuel used to cook the same meal is
half.

Dr Karve's 100gm-per-time charcoal cooker could be very polluting in
terms of CO per Kg of fuel burned, but it would not matter if the only
alternative was burning 500 gm of wood, even if the total CO output was
more than 1/5 as much per gram. If someone measures the CO levels in
his stove at 1250 ppm CO it tells us exactly nothing about the
combustion. He might be burning all the charcoal in a very small amount
of air quickly and efficiently with very little excess air. The
combustion products might be very concentrated. If you harassed him
about the CO level he could make the air inlet door a little larger and
get a 'better CO level' without improving the combustion at all, or
perhaps even making it worse. The only way to know is to compare the
CO/CO2 ratio.

With this background, I will report on three different types of
experiment that I have measured so we can talk about how to standardize
stove emission testing in a meaningful way.

Test Type 1
I lit a downdraft coal stove using a dreadful oily coal from Witbank
using 1 sheet of newspaper and 200 gm or wood. In the initial lighting
phase the CO level was 15% of the CO2 level and there was dense white
smoke in the chimney.

Once the wood and paper had mostly burned away and the coal was lighting
(short, dark, red flames with a lot of black smoke from the flame tips)
the CO level dropped to 4.4%. The reason that is was that low is that
is just the nature of a downdraft stove. The flames are drawn over the
hot coals and the smoke is burned.

As the coal got going (still lots of black coals on fire) the CO level
dropped lower and lower until it stabilized at 1.5 to 1.8%. This means
that the whole smoke volume could have been vented into a kitchen and it
would still be 7.5/1.5 = 5 times cleaner than a Panda paraffin stove.

When the coal finished 'coking' and was nothing but red hot coals, the
chimney gasses were completely clear and one would expect that the stove
would finish burning the fuel over the next couple of hours without
'smoke'. Well after the coal finished going from black to red coals,
the CO level steadily rose. The heat output also increased (double to
triple) and the absolute CO concentration in ppm increased. This means
that more carbon was being burned per minute, and that it was not
getting enough air. The CO stabilized at 9% when the fire appeared
visually to be in its 'cleanest' phase. It is this condition that the
South African mbaula (open-topped paint can stove) is taken indoors for
space heating! Yikes!

In general, except for the initial lighting, the visibility of smoke
(visible PIC's) did not correlate to CO levels at all.

When I added a few new lumps of coal to the combustion chamber to creafe
more red flames, the CO level dropped to 7% as it ignited. This bears
further investigation.

Test Type 2
I lit a wood fire in a Vesto and got all sorts of figure depending on
how much fuel was in it, what type of wood, how small it was split how
short it was cut and whether or not the air controller was closed or
open. As one might expect, dry hard wood in chunks that did not heat
and gasify too quickly was the best performer in terms of emissions with
1-2% being achievable for long periods of time. In the 'dying embers'
stage the CO rises to 10% or more unless it is allowed extra air by
raising the can slightly (as the manufacturer recommends). The worst
figures (12-15%) are seen when overloading the combustion chamber with
very dry or small or smokey branches with bark. There simply isn't
enough air getting in to burn the smoke properly.

In general, there was a good correlation between visible smoke and CO
except at the end when there is only a small amount of charcoal left.
The absolute concentrations of CO in the Vesto are high compared with
open fires because it does not allow in a large amount of excess air (it
remains undiluted) but the combustion efficiency is very high.

Test Type 3
I use one of the newest gasifier conversions of the Vesto to check the
CO level when it was in 'gasifying mode' as described in an earlier
message to this list. Paul A must take notice of this test!

Once the fire was established and the wood was burning well, the primary
air was closed off and the stove thus turned into a wood gasifier. A
deck of bluish-yellow flame is established at the level of the secondary
air inlets (a circle of holes above the fuel). In this condition the CO
level dropped to 0.1% to 0.3% (0.003) of the CO2 level - a ratio of
1:333. The sample was drawn 'hot' from a point about 100mm above the
flames in the centre of the combustion chamber. This is extraordinarily
clean. (BTW the meter discounts the background CO and CO2 levels and is
H2 compensated.)

When the wood finally burned to charcoal, the CO began to rise. It
still continued to burn as a 'charcoal gasifier' but the CO level rose
to 5-6%. I lifted the stove to allow air to flow freely underneath and
up through the combustion chamber. The fire immediately jumped up in
intensity, the flames shortened and became intense, and the CO portion
nearly doubled! This bears further investigation. The Vesto burning as
a charcoal gasifier was cleaner than as a free-flowing-air charcoal
burner.

There was no meaningful correlation between visible smoke and CO
emissions.

CONCLUSIONS
Truly minimizing CO emissions seems to required one or more of these
guidelines:
1. Gasify the wood and burning the gas - close to the wood in the
case of the Vesto (to maintain the ignition). Total CO levels and CO
ratios are extremely low in wood gasifiers.
2. Quench the charcoal and saving or selling it to avoid the high
CO phase altogether - an approach favoured by some. It could perhaps be
burned in a more appropriate device with lower CO.
3 Add fresh fuel to the wood gasifier just as it reaches the
charcoaled stage. It works by mixing the CO from the charcoal with the
gases from the wood volatiles. Ideally refuel it a couple of minutes
before the volatiles run out when the flames change to mostly blue.
This can only be done in a stove designed to be refuelled 'on the fly'.
The batch load gasifiers are a problem in this regard.
4. Learn what causes CO to be high as visible smoke is nearly
useless as an indicator of CO levels except in the very beginning.
Without a meter you are whistling in the dark.

Best regards
Crispin

BioEnergy Lists: Improved Biomass Cooking Stoves

June 2004 Biomass Cooking Stoves Archive