The Stirling engine is an almost two hundred year old patented machine that uses differences in heat to produce kinetic energy. Sounds like magic? It’s not!
Simply put a Stirling engine is much like a gasoline engine only the expansion inside the piston usually made by exploding gasoline is instead made by expanding air. A Stirling engine is sometimes called an external combustion engine as the heat source comes from outside the machine. This makes a Stirling engine handy for burning simple bio-fuels as these fuels don’t need to be refined to fuel quality in order to provide energy since the combustion will take place outside the machine’s system.
But the utilization of a natural external heat force such as solar or geothermal produces less carbon and no toxic waste (only waste heat). A common set up is for a parabolic mirror to be centered upon a Stirling engine which converts the heat of the sunlight to kinetic energy which can produce electricity.
Far from being a novelty the Stirling engine performs at a high level of efficiency, adapts well to different configurations and could easily once again become a mainstay of small-scale, low-impact power production.
Once popular in small home applications and poised for a resurgence, the Stirling engine is a sterling example of how rethinking the physics around us can reveal startling possibilities.