Carnotciklus

The Carnot cycle is a theoretical thermodynamic cycle that describes the most efficient possible heat engine operating between two temperature reservoirs. Proposed by Sadi Carnot in 1824, it serves as a benchmark for the performance of real-world engines. The cycle consists of four reversible processes: two isothermal processes and two adiabatic processes.

The first step is an isothermal expansion where the working substance absorbs heat from a high-temperature reservoir. This is followed by an adiabatic expansion, where the substance's temperature drops without any heat exchange. Next, the substance undergoes an isothermal compression, releasing heat to a low-temperature reservoir. The cycle concludes with an adiabatic compression, returning the substance to its initial state and temperature.

The efficiency of a Carnot engine depends solely on the temperatures of the hot and cold reservoirs. It is given by the formula: Efficiency = 1 - (T_cold / T_hot), where T_cold and T_hot are the absolute temperatures of the cold and hot reservoirs, respectively. This means that to achieve higher efficiency, the temperature difference between the reservoirs must be maximized.

While no real engine can achieve Carnot efficiency due to irreversibilities like friction and heat loss, the Carnot cycle provides a fundamental limit for heat engine performance. It is a cornerstone of thermodynamics, illustrating the relationship between heat, work, and efficiency, and has profound implications for the design and understanding of all heat engines.