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PowerPedia:Rotary Moon Stirling



RotaryMoonStirling is a Stirling engine design for solar concentrators, with a rotary displacer (or "shader"). It is hoped that it can get near the magical 1000 EUR / 1kWe cost (when home-built or mass-produced). It is optimized for cost, not for highest efficiency of heat => mechanical power conversion.

"Waste-heat" should be suitable for

ammonia absorption chiller (summer)

or simply to produce warm water (winter)

or possibly even for steam-generation

or a combination

The author thinks that a low-pressure ratio Ericsson cycle (similar to Brayton cycle gas turbine) with recuperator (with Tesla or bladed turbine) can be an even lower cost solution (definitely better power / weight ratio), but at a higher development cost. We seek cooperation for development. Results will be shared with the Archimedes project: open source solar concentrator and accessories

Stirling arrangement with rotary "moon-shaped" displacer, or "shader":

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Linkage between piston and displacer not shown. You can animate the [3D model] (povray and kpovmodeler).

An old drawing ( linkage would be outside in a practical implementation as temperature is quite extreme inside the tube, several hundred C, upto 800C on the sunny side ):

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a tank, similar to that of a compressor (black-iron material might be a good choice), behind glass. Solar concentrator mirrors in front

the opposite side of the tube is insulated. Cooling tubes inside (water, steam or aqeous ammonia inside for absorption chiller)

the rotary shader rotation is syncronised to the piston

o the shader can be a rather thin plate (no need to be hollow)

proposed initial pressure: 500 kPa (later higher)

displacement: with a 50L tank, about 4-8L

in the prototype, chaindrive (1/2 inch chain) is planned: 75 tooth for the displacer and the flywheel. 8 tooth for the alternator

A prototype will be made for appr. 800We, with the potential for upto 2kWe with suitable (15+ m2) mirror.


Project page: [other wiki]