Thermal efficiency is a measure of how well a system converts heat energy into useful work or output. It is expressed as a percentage, calculated by dividing the useful energy output by the total energy input. For example, in a steam engine, if 30% of the heat energy from burning fuel is converted into mechanical work, the thermal efficiency is 30%.
Higher thermal efficiency indicates a more effective system, which can lead to reduced fuel consumption and lower emissions. This concept is crucial in various applications, including power plants, automobiles, and refrigeration systems, where optimizing energy use is essential for sustainability and cost-effectiveness.