[Terrapreta] heat energy: stoves vs. thermo biopiles

[Sean K. Barry]

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<mailto:jeff0124 at velocity.net> 
  To: terrapreta<mailto:terrapreta at bioenergylists.org> 
  Sent: Friday, November 23, 2007 8:16 PM
  Subject: Re: [Terrapreta] heat energy: stoves vs. thermo biopiles


  Dear All,

  When one burns fuel, for the most part, you use the lower heating value of the 
  fuel.


  Jeff



  On Friday 23 November 2007 3:06 pm, Sean K. Barry wrote:
  > Hi Gerrit,
  >
  > I suspect its 80% of the released heat, not 80% of the combustible energy
  > in the biomass feed.  Capturing 80% of the combustible energy is about as
  > good as any complete combustion (burning) process could ever do.  That
  > would leave just ash.  It even 25 or 30% of the original carbon is left in
  > the biomass, then this constitutes at least 60% of the energy content of
  > the feed also.  I'm sure the total energy harvest efficiency from making
  > compost is much much lower than 80%.
  >
  > Compost does make better fertilizer, to be sure, than charcoal does, even
  > low temperature charcoal.  It has been suggested more than once on this
  > site that charcoal could be combined with compost to make a soil amendment
  > which is initially more fertile than fresh charcoal.
  >
  > Regards,
  >
  > SKB
  >   ----- Original Message -----
  >   From: Gerald Van Koeverden<mailto:vnkvrdn at yahoo.ca<mailto:vnkvrdn at yahoo.ca>>
  >   To: jeff0124 at velocity.net<mailto:jeff0124 at velocity.net<mailto:jeff0124 at velocity.net%3Cmailto:jeff0124 at velocity.net>>
  >   Cc: terrapreta<mailto:terrapreta at bioenergylists.org<mailto:terrapreta at bioenergylists.org>>
  >   Sent: Friday, November 23, 2007 12:19 PM
  >   Subject: [Terrapreta] heat energy: stoves vs. thermo biopiles
  >
  >
  >   Jeff,
  >
  >   I like the idea of hyour thermo biopile.
  >
  >   Composting to produce energy definitely has the advantage of
  >   producing a much better fertilizer- the compost - than ash from
  >   burning.  But it seems that less total energy is available by
  >   composting, though if the biomass had to be dried before burning, the
  >   resultant net energies might be conquerable?
  >
  >   A company in Canada (Global earth Services/Products) sells a compost-
  >   maker with a built-in heat exchanger.  They claim to capture 80% of
  >   the energy.  I interpret this "80%" to be 80% of what would be the
  >   combustible energy.
  >
  >  
  > http://www.globalearthproducts.com/heat_extraction.htm<http://www.globalear<http://www.globalearthproducts.com/heat_extraction.htm%3Chttp://www.globalear>
  >thproducts.com/heat_extraction.htm>
  >
  >   Gerrit
  >
  >   On 23-Nov-07, at 12:34 AM, Jeff Davis wrote:
  >   > Dear All,
  >   >
  >   > Right now all my time is going into the Thermo Biopile:
  >   > http://www.puffergas.com/pile/pile.html<http://www.puffergas.com/pile/p<http://www.puffergas.com/pile/pile.html%3Chttp://www.puffergas.com/pile/p>
  >   >ile.html>

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