Carnot Cycle Efficiency

The Carnot cycle efficiency (η) is a theoretical maximum efficiency that a reversible heat engine operating between two reservoirs can achieve. The formula is derived from the Carnot theorem, which states that no engine can be more efficient than a reversible heat engine (the Carnot engine) operating between the same high temperature (T_hot) and low temperature (T_cold) reservoirs. It is essential that temperatures are in the same units (e.g., Kelvins) when calculating the efficiency.

In practical applications, real engines cannot reach this efficiency due to irreversible processes such as friction and heat loss. However, the Carnot cycle represents an idealized model that provides a benchmark for the efficiency of real heat engines. In the thermodynamic formula, the temperatures are absolute temperatures, measured in Kelvin (K).