Closed chamber Stirling engine generator.

[Groundloop]

Hi All,

I have got an idea on how to convert solar heat to electricity. My proposal is to use an completely closed cycle Stirling engine and convert the solar heat direct to electricity by the use of a powerfull Neo magnet and a pickup coil. The Stirling engine has just one moving part. The engine is cooled by water and the hot water byproduct can be used to heat your home or for hot water usage. The Stirling engine can use other gasses than air. Hydrogen, Helium, Nitrogen is some. The solar energy can be collected by a parabolic disk or by Fresnel lens.

I have not build this motor generator and probably never will because I lack the tools and skills to do that. In any case, this is open source information. I hope that someone with the right tools, materials and skills can take this idea into reality.

Groundloop2003.

[Groundloop]

All,

At mid day in the summer the Sun will provide approx. 800 Watt of energy pr. square meter area.
A solar panel of approx. a square meter area will give you approx. 100 Watt of energy. An Stirling
engine is very effective. Maybe it is possible to convert more of the 800 Watt to electricity when we
compare the area exposed to the Sun.  What do you think?

Groundloop.

[tinu]

Hi Groundloop,

Stirling usually needs two pistons. One piston variation can be imagined, though.
However, in the variant proposed I think the piston will barely move at best (very small amplitude and tiny motive force) and if it does move at all it will end stuck to the right (cold) side. I can?t see why it would leave that position once getting there.

I?ve also got excited over the time by the idea of solar-heat-electricity but shortly afterward I realized that the efficiency of a thermodynamic engine will be limited to approx. 10% (max. Carnot) considering a reasonable temperature difference of 30Celsius that can be achieved. 10% of >1Kw/sqm of solar energy may not sound too bad on paper but it actually poses a lot of technical challenges in practice because of the cumbersome cylinder and pistons which will weight proportionally to their size (about 1sqm for the displacer), thus generating a lot of friction especially also when considering the sealing requirements for the main piston. Also because at smaller temperature gradients the heat transfer is much slower, any engine of this kind will have a very low RPM ? another nightmare to be overcome.

I?ve seen enough movies of various Sterling engines but not a single one to run on solar energy, although many seemed to happily work above a cup of coffee. I wonder why.

Anyway, I am open for contributing to a thoroughly debate regarding solar-heat-electricity conversion if enough interest exists. After all, solar energy is quite abundant and at about 5USD/W in photovoltaic panels there is at least a theoretical chance to come with something cheaper.

Cheers,
Tinu

[Groundloop]

@tinu,

First, you havent seen much I bellive. 

http://www.sandia.gov/news/resources/releases/2004/renew-energy-batt/Stirling.html

The difference with my design is that there is just ONE moving part.

Next, the temprature difference will be some 1000 Degrees or more in a solar powered Stirling.
The cold side will be approx 90 Degrees Centigrade. (Water cooling, remember.)

A closed cycle Stirling with one piston is no problem to manufacture.


Before you "doom" a project please get some information first!

Groundloop.

[tinu]

@ Groundloop,

Don?t be that sensitive, now!
Figures are welcome. One moving part is great but it won?t make it workable more than 1RPD (rotation per day) or 1 RPC (per cloud  ). I know it because I?ve also designed my own stirling 1 moving part variant. It simply takes more than what's depicted in the above schematic.

Your project is not doomed. Who said it was? Instead, just keep elaborating on it and developing the subject to see how far it/you can go.
As about competing with Sandia that would be another story?

Cheers,
Tinu