RotaryMoonStirlingEngine

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.

Apparently others have invented the same concept independently. mousedown="yt.analytics.urchinTracker('/Events/VideoWatch/ChannelNameLink');" href="http://www.youtube.com/user/mdevink">mdevink also built a working prototype: video

"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. Result will be shared with the Archimedes project: open source solar concentrator and accessories

Arrangement with rotary "moon-shaped" displacer, or "shader":

img src="http://www.ideje.hu/images/Energy/StirlingMotor/RotaryMoonShaderStirling.png"

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 ):

img src="http://www.ideje.hu/images/Energy/StirlingMotor/MarcellGal_StirlingMotor_m.jpg"

• 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
  • 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.