Stirling Cycle Engine, Two-Cylinder Alpha Type

Invented by Scottish inventor Robert Stirling in 1816, the Stirling Cycle Engine is a practical 'external combustion' engine that transforms any heat source to mechanical energy. It is one of the most efficient mechanical methods of doing this. While it has been useful in niche applications for many decades, and remains so today, it is not as widely known as internal combustion engines and other kinds of external combustion engines, such as steam engines. It is best when running continuously in applications where the exact speed is not critical, and where rapid changes in its speed are not required. Because of this is has not found use so far in automobiles, but with the return of electric cars, it my find some application as a way to generate the electric power needed by the cars. Otherwise, it has traditionally found use for pumping water, for remote electrical generation, as well as other situations.

All Stirling Cycle engines use an enclosed fluid, usually air, that simply moves back and forth in the engine. Most types use two cylinders, one whose job is primarily to do the 'work', and the other whose job is to help move the fluid back and forth in the engine. All Stirling Cycle engines use the difference in temperatures between two parts of the engine as their source of energy .

The Alpha type engine shown here uses two cylinders, moving the fluid back and forth between them. One cylinder is kept warm (in this case by a small alcohol burner) while the other cylinder is kept relatively cooler (in this case by an air cooled heat sink). The speed of the engine is controlled by the difference in the two temperatures.

The engine in this video is machined from aluminum, with a wooden base and glass 'hot' cylinder. It was obtained from Sci-Supply.com, and is a ready-to-go engine that does not require assembly.

Wikipedia and HowStuffWorks have good descriptions of exactly how Stirling Cycle engines work.

Category:

Science & Technology

Tags:

• Stirling cycle
• Sterling cycle
• external combustion

[youtuuba]

The question is, is this engine an Alpha or a Gamma type?

Not being an expert on the fine distinctions between types of Stirling Cycle Engines, my classification is based on two things:

- On Wikipedia, another engine that appears to be functionally the same but with a different physical layout is identified specifically as as Alpha.

- A Gamma engine is a Beta engine in which the power piston and displacer piston are separated into two cylinders. But this engine seems to not have a displacer.

[producedIbyIts]

It is a gamma type, because the displacer is in the heated piston and the other piston is the powerpiston.

[mistergrady]

Is gamma type.

[charly1gi]

Paul, this engine surely performs well.

[simi112]

Is this not a gamma? 5*