[Stoves] Heat transfer and in-line water heater

[Thomas Reed]

Dear Steve, Andrew and All:

Radiation goes as

    W = seA (T2^4 -T1^4 )

where s is the Stefan-Boltzmann constant, (5.670 400(40)×10^-8 W 
<http://en.wikipedia.org/wiki/Watt>·m^-2 ·K^-4  [I prefer to remember is 
at 5.67 Watts/cm2 (K * .001), thinking in thousands of Kelvins] e is the 
effective emissivity, (1 for carbon and .01 for silver);  A is the area 
of the emitter and T2 is the emitter and T1 the receiver.

Because of the fourth power dependency you can usually ignore T2 if it 
is less than 3/4 of T1.

Let's all be grateful to Stefan and Boltzmann.

TOM REED    BEF


Since

Steve Taylor wrote:
> andrew wrote:
>   
>>>>>    
>>>>>         
>>>>>           
>>> Temperature DIFFERENCE.
>>>     
>>>       
>> I don't think so Steve, that's true of conduction (where adjacent 
>> atoms jostle each other to exchange energy) but radiation is 
>> absolute and is related to the 4th power of the absolute 
>> temperature.
>>   
>>     
> So do two objects at identical temperature radiate to each other ?
> I thought thats why a black body radiator works, and why you can't see 
> the inside of a fire very well
>
> Steve
>
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