1. Closed Cycle: Unlike a steam engine, a Stirling engine operates on a closed cycle, meaning that the working fluid (usually a gas such as air or helium) is sealed within the engine and undergoes a series of processes without escaping.
2. Heating and Cooling Process: The engine consists of two cylinders: a hot cylinder and a cold cylinder. In the hot cylinder, the working fluid is heated by an external heat source, causing the gas molecules to move faster and expand. In the cold cylinder, the working fluid is cooled, causing the gas molecules to slow down and contract.
3. Regenerator: Between the hot and cold cylinders is a component called the regenerator, which is a porous material that stores heat. As the working fluid moves from the hot cylinder to the cold cylinder, it passes through the regenerator, transferring some of its heat to the material. Similarly, as the working fluid moves back from the cold cylinder to the hot cylinder, it absorbs heat from the regenerator, reducing the amount of heat required from the external heat source.
4. Expansion and Compression: The heating and cooling processes cause the working fluid to expand and contract, driving the engine's pistons. When the working fluid expands in the hot cylinder, it pushes the piston outward, generating power. When the working fluid contracts in the cold cylinder, the piston moves inward, compressing the gas.
5. Power Generation: The reciprocating motion of the pistons is converted into rotational motion through a crankshaft, which can be used to generate power or perform mechanical work.
The Stirling engine is a thermodynamically efficient engine that can operate on various heat sources, including solar, biomass, or waste heat from industrial processes. However, due to its complex design and relatively high cost compared to other internal combustion engines, it has limited commercial use. Nevertheless, it's a unique and interesting example of heat engine technology.
