közelreverzibilis

A közelreverzibilis or near-reversible process describes a thermodynamic process that occurs so slowly and in such small steps that it remains infinitesimally close to equilibrium throughout its duration. In an ideal reversible process, the system is always in perfect equilibrium with its surroundings. A near-reversible process approximates this ideal by minimizing the irreversibilities that prevent a truly reversible transformation.

These irreversibilities often arise from factors such as friction, viscous dissipation, and finite rates of heat transfer. For a process to be considered near-reversible, these dissipative effects must be negligible. For example, a gas expanding very slowly against a piston with no friction would be a near-reversible expansion. Similarly, a chemical reaction proceeding extremely slowly under conditions where heat exchange is very efficient could be considered near-reversible.

The concept of near-reversibility is crucial in thermodynamics for defining the maximum possible efficiency of engines and refrigerators. Real-world processes are always irreversible to some degree, meaning their efficiency will always be less than that of an equivalent idealized reversible process. Engineers and scientists often analyze near-reversible processes to understand the theoretical limits of thermodynamic cycles and to identify areas where irreversibilities can be reduced to improve performance.