Larry's Blog

Stirling Engines

I am very much interested in building Stirling Engines. To start with I had 3 failures: a test tube Stirling Engine, a home brew Stirling Engine built out of a pneumatic cylinder, and a tin can Stirling Engine. Eventually, I got the tin can Stirling Engine to run for 15, 20 and 30 seconds.

I retired at the end of June, 1997. I have set up 2 six foot white countertops in my basement with overhead flourescent lighting. I have constructed some clock escapement mechanisms, a differential gear mechanism made of wood (which is like an analog adder), the Stirling Engines and a water pumping system with plastic tubing and a few solenoid valves for controlling the flow.

The Stirling Engine works on the idea that an enclosed parcel of air will expand when heated, and contract again when the heat is removed. When the air expands it can push an attached piston outward since the air pressure of the air parcel exceeds the outside air pressure. When the heat is withdrawn and the air contracts, the outside air pressure exceeds the pressure of the air parcel, and pushes the piston back in. Now the trick of a Stirling Engine is to move the air rapidly back and forth from the HOT END of an air cylinder to the COLD END of the cylinder. This is accomplished by a mass of material which moves back and forth in the cylinder. The material simply displaces the air from one end to the other for heating or cooling. Notice that the movement of the piston is approximately 90 degrees out of phase with the displacer motion.

For a STIRLING ENGINE project: http://www6.norfolk.infi.net/~babcock/stirling.html

Return to Main Page.