Are Stirling engines really the most efficient (heat) engines possible?
In the mid 1800’s a very bright Frenchman named Sadi Carnot figured out the maximum efficiency possible with any heat engine. It is a formula like this (Temperature of the hot side – Temperature of the cold side)/Temp of hot side x 100 equals the max theoretical efficiency. Of course the temperatures must be measured in degrees Kelvin or Rankine. Stirling engines (with perfect regeneration) match this cycle. Real Stirling engines can reach 50 percent of the maximum theoretical value. That is an incredibly high percentage!
