[Stoves] Calculation help

[ajheggie at gmail.com]

On Monday 09 January 2012 20:03:26 Frank Shields wrote:
> For the LHV calculation of methane;  I see wiki says the HHV is product
> of water in liquid form and LLV is product of water in vapor form -
> same way you calculate biomass. But, of course water is never in the
> liquid form (until it completely condenses at below 100c.). Hydrogen is
> held by carbon or then water vapor at the combustion temp. so I am
> surprised they calculate (estimate) it the way they do.

Frank, I may not have been paying enough attention to your posts and 
haven't looked at the wiki page but it is as I understand it and I'd like 
to see where you don't agree.

HHV is the heat released by the combustion including all the heat 
realeased when hydrogen is oxidised to H2O and all the products of 
combustion are referred back to an initial temperature ( so all the H2O 
released as a gas is condensed and gives up its latent heat ( Enthalpy of 
vaporisation). 

LHV is the same but assumes all the H2O from the oxidation of hydrogen 
remains as a vapour above its dew point.

With methane IIRC this amounts to a 6% difference in heats.

AJH