[Terrapreta] heat energy: stoves vs. thermo biopiles

[Jeff Davis]

HHV and LHV isn't about the moisture in the fuel it's about the fuel. If you 
took pure H2 and oxidized it, burned it, your end products would be heat 
(energy) and H2O (water). Notice that this fuel is not biomass and has no 
moisture in it from the get go.

The total heat (energy) from burning this fuel is the heat in the steam/water 
plus the heat (energy) from the flame.

HHV = flame energy + steam energy

LHV = flame energy


I'm sure this is over simplified but kind of the idea.


Best wishes,


Jeff


Sean wrote:
> 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.