[Stoves] Stove Material Properties

[Robert Penn Taylor]

Tae,

As Crispin pointed out earlier, the question of whether you want low 
thermal conductivity depends on the flow path through the stove and how 
the combustion is staged.

Consider a stove that has a cylindrical combustion chamber, with a 
second cylinder around that. Overfire air for staged combustion passes 
through the space between the two cylinders and then dumps into the top 
of the inner cylinder (combustion chamber). If you want to pre-heat the 
overfire air, you don't want low thermal conductivity in the inner 
cylinder. Generally though, you do want low thermal conductivity in the 
*outer* walls, because for most cookstoves this is "lost" heat.

If your stove doesn't do staged combustion, and you don't do any 
pre-heating of air, then yes, in general you want to minimize the 
apparent thermal conductivity of the walls. You also want to minimize 
total heat capacity of the walls.

-Penn

-- 

Robert Penn Taylor
Graduate Research Assistant
Department of Mechanical Engineering
Iowa State University
(515) 294-5311

Tae Young Lee wrote:
> Thank you Crispin and Robert.
> 
> I have another question:
> When trying to build an insulative wall for a stove(only focusing on  
> the stove material), is achieving a low thermal conductivity the  
> primary objective since other parameters such as convective heat  
> transfer coefficient depends on the air flow, etc.? From various  
> papers I have looked at, it seems that they all relate the performance  
> to thermal conductivity. Also, I have found numerous papers  
> correlating bulk density or porosity to thermal conductivity, but when  
> I calculated the R^2 values for those, the highest I've found is only  
> 0.19, which is ridiculously low. To me, there is no correlation  
> between those properties. Could you comment?
> Thank you very much.
>