Written by the Fiveable Content Team • Last updated August 2025
Verified for the 2026 exam
Verified for the 2026 exam•Written by the Fiveable Content Team • Last updated August 2025
Definition
Heat engines are devices that convert thermal energy into mechanical work, typically by allowing heat to flow from a high-temperature region to a low-temperature region.
While heat engines convert thermal energy into useful work, heat pumps transfer thermal energy against its natural flow for heating or cooling purposes.
Efficiency measures how effectively a heat engine converts thermal energy into useful work. It is calculated as the ratio of output work to input heat.