So I've got this crazy idea. To put it simply, to use the heat from anaerobic composting to power hot-air engine, specifically a Stirling Engine. Based solely on my own reading, the center of a closed composting heap can reach anywhere from 120-160 degrees without killing the microorganisms required to produce methane. By water cooling the cold side of an engine, a temperature differential of >100F. I imagine a gamma configuration with opposed/linear cylinders: hot cylinder down, cold cylinder up out of the heap. Compressed helium as the working gas will increase efficiency. And a properly built Stirling Engine requires a regenerator to further increase efficiency. I'm the guy with the ideas, but I don't know how to do the complex gas equations, cylinder computations, electrical computations and etc. required to calculate the dimensions. As well as the necessary torque to run, say, an alternator. Trying to upload concept sketches. Any help would be much appreciated!