Wärmemaschinen

Wärmemaschinen, also known as heat engines, are devices that convert thermal energy into mechanical work. This process typically involves a working fluid that undergoes a cycle of heating, expansion, cooling, and compression. The fundamental principle behind their operation is the second law of thermodynamics, which states that heat naturally flows from a hotter region to a colder region, and not all of this heat can be converted into useful work.

The basic components of a heat engine include a heat source, a heat sink, and a working substance. The heat source provides the thermal energy, often through combustion or nuclear reactions. The working substance, such as steam or gas, absorbs heat from the source and expands, performing work by pushing a piston or rotating a turbine. After performing work, the working substance releases waste heat to the heat sink, a colder reservoir, and then returns to its initial state to repeat the cycle.

Common examples of heat engines include internal combustion engines found in vehicles, steam engines used in power plants and historically in locomotives, and jet engines used in aircraft. The efficiency of a heat engine is limited by the Carnot efficiency, which depends on the temperatures of the heat source and the heat sink. Higher temperature differences generally lead to higher efficiencies, but practical limitations and energy losses always result in efficiencies below the theoretical maximum. Heat engines are crucial for transportation, electricity generation, and many industrial processes.