[Stoves] Calculation help

[Frank Shields]

Think I finally got it - thanks. Not sure why I had so much trouble as it
now seems so simple. ... So thinking we go from 20c up and back down to 150c
for cooking stoves unless there is a better suggestion.


Thanks again for the time.

Frank

Frank Shields
42 Hangar Way
Watsonville,  CA  95076
(831) 724-5244 tel
(831) 724-3188 fax
frank at bioCharlab.com











-----Original Message-----
From: stoves-bounces at lists.bioenergylists.org
[mailto:stoves-bounces at lists.bioenergylists.org] On Behalf Of
ajheggie at gmail.com
Sent: Monday, January 09, 2012 2:12 PM
To: Discussion of biomass cooking stoves
Subject: Re: [Stoves] Calculation help

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



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