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Cool Solar Thermal Panels

Posted: Thu Jul 09, 2009 9:41 am
by sjknuj
I'm looking at a solar thermal system for house heating via in floor
radiant heat. The solar folks tell me I need a large tank to hold the
excess heat generated in the summer. Could I use a Stirling engine to
dissipate the heat, cool my home or generate electricity? It seems
there must be a green solution that is cost effective. I'm not
looking at efficiency in home cooling or electricity the main goal is
to dissipate excess heat. Of course, I need a reasonable payback on
the dissipation technology.

Is this feasible? Has anyone ever heard of this sort of Stirling
engine use or know of someone who could reasonably create this sort of
system?

Response to Cool Solar Thermal Panels

Posted: Mon Jul 13, 2009 8:37 am
by stan.hornbaker
The large tank would have to be VERY LARGE for proposed application. The use of a Stirling engine would be totally impractical as it would have to generate power to drive a Stirling or other cooling machine.

There are no Stirling engine available in today's market to even consider.

Response to Cool Solar Thermal Panels

Posted: Mon Jul 13, 2009 1:44 pm
by bptdude___2569

I try to bite my lip lately, and be quiet, but think about what you are being told. Your solar thermal will create 'too much' heat? To them, it is a problem if temperatures go above what would turn the fluid in the system, water, to steam.

Some industrial evacuated tubes are relatively cheap to make compared to photovoltaic. They also collect energy better in areas that are temperate and often cloudy. If let loose to what they can do, they can heat the hot end up to several hundred degree C, and not break down.

If you used oil instead of water, as a transfer fluid, storing it in a tank, there are in fact several Stirlings out there already or about to come to market, that could have the hot end inserted into this tank, and run fine to produce a steady flow of power, even overnight, when there is no sun, if designed right.

Now I creap back into my hole.


Response to Cool Solar Thermal Panels

Posted: Mon Jul 13, 2009 2:19 pm
by bptdude___2569

Oh, one more thing.

You probably will neither be able to ask the people selling the solar thermal about these temperatures nor the Stirling engine people about the heating method.

The evactuated tubes you are probably looking at, have much better infomration about them and high end units, found on open source U.S. government lab data found with some googling. The numbers are impressive, indicating it is absolutely the best way to recover solar energy. You will have to dig that yourself, sorry, but trust me.

The Stirling engine people will not have heard of putting the hot end in oil, which they should do anyways. It makes the engine run more consistently, with less heat, and also makes the engine last longer compare to what they typically do, light a direct fire under the metal heat collector.

Now, truly, I have to run for my hole... bye bye