The Stirling engine, a solution to our energy problems?
The Stirling engine runs on heat and is very safe. Is this the solution to our energy crisis?
The Stirling engine was invented in the early 19th century by the Scottish Reverend Robert Stirling. He noticed that quite a few of his parishioners were seriously injured by accidents involving steam engines. Instead of seeking refuge in theology, he decided to find a practical solution to this problem. The result was this heat-powered engine, an absolutely safe alternative to the steam engine.
How does a Stirling engine work?
A Stirling engine works by draining a temperature difference between a hot and a cold heat reservoir. As the heat flows from hot to the engine, the air in a piston is heated up. This causes this air to expand.
This pressure difference sets the piston in motion, causing it to come into contact with a cold reservoir. As a result, the heat from the Stirling engine flows to the cold reservoir, causing the air in the piston to cool down and the piston to move back.
The movements of the piston drive a wheel. There are several variations on this principle, but they all boil down to the fact that heat flows from hot to cold, air expands and contracts, causing a flywheel to move.
What can you do with a Stirling engine?
Unlike, say, a gasoline engine or a diesel engine, which are very picky about their fuel, a Stirling engine is very versatile. All he asks is a temperature difference. You can run this type of engine on any heat source, even your body heat.
The greater the temperature difference, the more power the Stirling engine can deliver. Connect a generator, for example a bicycle dynamo, to your wheel and voilà! There is your electricity source. Also, this type of motor is very quiet and reliable because there are few moving parts in it.
Why don’t we see them everywhere yet?
The main disadvantage of the Stirling engine is that this engine produces relatively little power. It is not a powerhouse such as a petrol engine or a gas turbine. You also have to generate a temperature difference if there isn’t already one, and that, of course, also costs energy.
Still, the Stirling engine is interesting. For example, you can put a Stirling engine on a stove and let it pump the heat from a stove into the room. That heat eventually ends up in the room anyway, so you can also get extra electricity from it. This way you can enjoy your stove twice as much.
