Carnot efficiency

Carnot efficiency refers to the maximum possible efficiency of a heat engine operating between two temperatures. This concept was introduced by Sadi Carnot and is a fundamental principle in thermodynamics.1234

Carnot's theorem states that no engine working in a reversible cycle can be more efficient than any other engine operating between the same temperature limits. The efficiency of such an engine is solely dependent on the temperatures it operates between, not its mechanical design or the substance it uses.53

The efficiency ((\eta)) is calculated as the ratio of work done (W) to the heat absorbed (Q₁), or equivalently, ( \eta = 1 - \frac{T_2}{T_1} ), where (T_1) is the high temperature and (T_2) is the low temperature. This principle implies that 100 percent efficiency is impossible for any heat engine.143