Re: SFish type concept. Will it actuall work?

In article <Itmmj.458$5K1.59@[EMAIL PROTECTED]
>,
Fred Klingener <gigabitbucket@[EMAIL PROTECTED]
> wrote:
>"Frank Scrooby" <X@[EMAIL PROTECTED]
> wrote in message
news:fnchp1$1j1$1@[EMAIL PROTECTED]
>> Greets
>>
>> Spotted these links:
>> http://www.popularmechanics.com/science/earth/4243793.html
>>
>> http://www.johnsonems.com/jhtec.html
>>
>> Wonder what the residents here would think?
>
>Sign me up. The fundamentals are there. I hate and end up not paying any 
>attention to SF (or listen to political campaign promises) that
violate(s) 
>the first or second laws of thermodynamics. JTEC doesn't, so that
attribute 
>alone sets it apart.

I quote from the article:

"says he can achieve a conversion efficiency rate that tops 60 percent
with a new solid-state heat engine."

Using the aforementioned 2nd law of thermo, the maximum possible
efficiency
of a heat engine is:

      Th -Tc
Eff = ------ 
        Th

If Tc is "room temperature", or 293K, then Th has to be at least 732K or
459C (or 859F).  In order for his "solid state heat engine" to work over
that temperature difference, whatever magic material it is made of has to
retain its magic properties at the high-end temperatures.  Color me very,
very skeptical.

>This is especially true in cases where the heat input is "free" - e.g.
solar 
>or waste heat from a central station power plant (or, as with Watt,
you're 

If you are trying to extract energy from the waste heat of a power plant,
you are getting in the way of the power plant's attempt to dump that heat.
Better to improve the efficiency of the big-ass heat engine that is
dumping the heat (and will work better the lower its "cold side"
temperature
is) than to put a second heat engine between it's exhaust and the ambient
temperature.


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