Stirling Engine
The main positive aspects of a Stirling Engine:
- Is an External Heat Engine. In other words, it functions by having a heat differential applied to it's hot and cold ends from outside the engine itself.
- Is Fuel Source Flexible. So long as the "fuel" can produce heat (or cold!), it can be used. You can also use multiple sources as needed so it is not impossible to use heat from solar concentrates during the day and burn gas or wood during the night and on cloudy days.
- Is Reversible, meaning you can do both of these:
- Put in a temperature difference to generate mechanical motion.
- Put in mechanical motion to generate a temperature difference.
- Is Quiet compared to other engines.
- Is Safe as it doesn't need to contain any high pressures like steam and internal combustion engines.
Some negative aspects of Stirling Engines:
- They require an initial mechanical push to get started if at a stand still.
- They need to be sealed air tight. And air is not the preferred internal working gas, though air is still plenty functional. However, gases with a lower specific heat is better.
Design
Engine Cycle
- Isothermal compression within the cold end as heat is expelled from the system.
- Constant-volume heat addition.
- Isothermal expansion within the hot end as heat is added to the system.
- Constant-volume heat rejection.
Working Fluid Gas Properties
The working fluid, that which is seal inside the engine, effects efficiency of the engine.
Temperature Difference and Efficency
Some Links
DIY projects:
- Older 3D printed design. Has link rot so kinda hard to actualy build.
- Newer 3D printed design
- Plans for stirling engines built from aluminum cans