Quote from: K-Dog on Apr 03, 2024, 11:42 AM46 minutes in Alister Hamilton mentions Sterling Engines.  I am going to build one.  I have been looking at them recently.  That part of the discussion is off point.  But interesting to me.  I want something that will use the earth as a heat ballast and take the air temperature difference to operate from.  On a hot day perhaps the cool reservoir could be cooled with evaporation.  All I am after is a few watts which I think I can do.

Stirling Engies have long been my favorite low-tech means of converting Solar-Mechanical energy directly, or Solar-Mechanical-Electric by using a simple electric generator instead of needing silicon wafers grown in a laboratory.

Fresnel lenses provide a cheap means of concentration the solar radiation to heat your liquid reservoir to vaporization temprature, then you use the vapor pressure to do the mechanical work of turning a pump or a generator magnet-coil for the electricity.



alternatively or in combination with the fresnel lens, you can use solar heated piping to preheat the cool liquid as it returns from the condenser to the storage tank for heating to vapor stage.



If you can't get your water tank to boiling temperature, you can use a heat exchanger to take the hot water and vaporize a liquid like methanol with a low boiing point.  You work with lower pressure so not as much power per stroke, but at lower temperatures it does the job of converting heat to work.

A nice goal to start I think is enough juice to keep cell phones charged, then move up to laptops.  Also run a water pump to raise water up to a high storage tank.  Then you could use that as a battery to drive a micro-hydro electric generator to make electricity as the water coming down turns a turbine, like a waterfall.

Take some pics or make a video when you get going on the project!

RE