[Terrapreta] heat energy: stoves vs. thermo biopiles

[mmbtupr at aol.com]

from  Lewis L Smith

Many years ago, stack gasses were used to dry bagasse before combustion 
in a few cane mills. But one had to be careful not to extract so much 
heat that the exit temperature from the dryer allowed condensation of 
sulfur compounds.  ###

-----Original Message-----
From: Duane Pendergast <still.thinking at computare.org>
To: 'Sean K. Barry' <sean.barry at juno.com>; jeff0124 at velocity.net; 
'terrapreta' <terrapreta at bioenergylists.org>
Sent: Sat, Nov 24  7:40 AM
Subject: Re: [Terrapreta] heat energy: stoves vs. thermo biopiles

          Sean,

 

As I recall from tests done with a “bomb” calorimeter
as part of my engineering education, HHV referred to the amount of 
energy
available when the steam portion of the products of combustion of a dry 
fuel is
condensed. LHV referred to the energy available if the steam is not 
condensed.

 

Wikipedia confirms I’ve not lost all.

 

http://en.wikipedia.org/wiki/Higher_heating_value

 

That’s a little different concept than that of using energy
to drive off moisture pre-combustion – and I see Jeff Davis has already
responded to this effect. Oh well – repetition is the best teacher.

 

Duane

 

-----Original Message-----

From:
terrapreta-bounces at bioenergylists.org
[mailto:terrapreta-bounces at bioenergylists.org] On Behalf Of Sean K. 
Barry

Sent: November 23, 2007 11:51 PM

To: jeff0124 at velocity.net;
terrapreta

Subject: Re: [Terrapreta] heat
energy: stoves vs. thermo biopiles

 





Hi
Jeff,





 





Yes,
I think you are right.  The lower heating value (LHV) is used versus the
higher heating value (HHV) because there is usually energy lost in
driving water out of the feedstock before any energy can be used from 
the
combustion.  This assumes that 100 C heat is not usable.  However, if
there is a use for relatively low quality heat (e.g. green house 
warming in
cold climes), then 100 C might be usable. 





 





Also,
if a feedstock is dry then the LHV and HHV are closer in practice.  The
HHV is, I believe, actually measured as heat generated from the 
combustion of
"bone dry" (0% moisture content) feedstock.





 





Regards,





 





SKB







-----
Original Message -----





From: Jeff
Davis





To: terrapreta





Sent: Friday, November 23,
2007 8:16 PM





Subject: Re:
[Terrapreta] heat energy: stoves vs. thermo biopiles





 



 _______________________________________________
Terrapreta mailing list
Terrapreta at bioenergylists.org
http://tech.groups.yahoo.com/group/biochar/
http://terrapreta.bioenergylists.org
http://info.bioenergylists.org



________________________________________________________________________
Email and AIM finally together. You've gotta check out free AOL Mail! - 
http://mail.aol.com