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From: Ken James (no email)
Date: Sun Apr 08 2007 - 21:35:50 EDT
>> -----Original Message-----
>> Thermal power extracted from the sun and converted via stirling engines
>> may or may not be a feasible thing at scale up sizes, it is as yet
>> un-proven,
>>
>
> REPLY
> Only in America! Stirling engines have proven themseleves elsewhere in the
> world.
>
>
No one has yet proven that Stirling engines can be a practical and cost
effective method in the large scale 'energy grid' market.
>
>
>> but in any case it will not be entirely 'clean' as it takes
>> much petro chemical usage to make the engines, the stuff needed with
>> them, and lubes and ect to run them, and maintain them. -Ken
>>
>
>
> REPLY
> And the point is. . . .?
>
>
Without cheap oil, no method yet devised will be a 'goer'.
> Solar panels are not entirely clean either in the manufacturing process.
> Nothing is! But a durable product tha tlast twenty years is less polluting
> than something which has to be replaced in five years. Both PV cells and
> Stirling seem to fall into the 20 year usable catagory. How do you repair a
> bad PV cell famaged by hail for exampls
>
My panel is over 20 now and has seen several bad hail storms with no
damage...tempered glass...which takes more energy to mfg....is it more
cost effective than some tech or device that lasts only five years? Prob
yes, but it depends on what that other tech is. I would guess that a
solar panel will be more long lasting than the boilers and associated
equipment that the Stirling engine needs, but that does not mean it
would be more cost effective.
> A Stirling engine can be fixed with new bearings and piston rings.
>
And new boilers, pumps and etc for a more traditional approach that uses
them. Even one that focus the sun right on the engine is more complex
than just rings and pistons, as there are heat dissipating surfaces, gas
seals, aiming equipment all of which can and will wear out. And how long
will the reflective surfaces last exposed to the weather as they are?
Wind generators also have a lot to recommend them, but lots of
disadvantages also. Nothing is free and so far none of this alt energy
is sustainable without cheap oil.
> Individual mirror sections can be replaced.
> The present trend appears to favor solar reflector type generating
> facilites. There must be some technical advantage over a plain PV array.
>
> What I am wondering about is why do they not use reflectors to concentrate
> the suns rays on a solar panel.
>
Some do but why should they if the solar panel can be made cheaply
enough over the larger area? It may well be too expensive to make them
able to take the higher energy level needed for concentration.
> I have a hunch the panels cannot tolerate the high heat.
Most cannot.
> Until this expeiemtn gives good proof
> of concept they are not going to spend money to develop these more eficient
> versions.
>
It may prove itself, I sure hope so we need all the help we can get! -Ken
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