[Stoves] Energy loss into stove walls

[Dean Still]

Dear Paul,

Ken's bricks are usually close to .8 grams per cc.

I used a rule of thumb when thinking about mass that most earth stuff is
around .25 cal/gram degree C...

Water is 1.0

I used to use something like the following with my students: You can evolve
an answer, I think.

http://www.scienceteacherprogram.org/chemistry/bodha00.html


"the pot was about 15 to 20 cm above the ideal position."

15cm is 6 inches! By the time the heat gets to the pot it might have cooled
off? We use 4cm between the pot and the insulated combustion chamber. Can
you try this and see if your fuel use is reduced?

Best,

Dean
-----Original Message-----
From: Paul S. Anderson [mailto:psanders at ilstu.edu] 
Sent: Saturday, August 04, 2007 9:01 PM
To: Discussion of biomass cooking stoves; Dean Still
Cc: 'Discussion of biomass cooking stoves'
Subject: Re: [Stoves] Energy loss into stove walls


Quoting Dean Still <dstill at epud.net>:

> Dear Paul,
>
> What is the temperature of the gases right below the pot?

At the combustor of the gases, the temperature should be about 900 to 
1000 C. But the pot support that I was using was too tall, so the pot 
was about 15 to
20 cm above the ideal position.  That situation is another factor
contributing
to the high fuel consumption, but separate from the heat loss into stove
walls
question.

Can you provide us with the specific heat capacity of the insulative 
bricks?  Or
please check that Ken Goyer has received these messages and see if he has
the
specific heat capacity value.  These were Ken's 6-brick-stove bricks that he
gave me 2.5 years ago when I visited him.

I will send another message very soon (same subject) in reply to what
Crispin
wrote.

Paul


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