Thermodynamic cycle

A thermodynamic cycle is a series of processes that involve the transfer of heat and work between a system and its surroundings in a way that the system returns to its initial state at the end of the cycle. In other words, a thermodynamic cycle is a closed loop in which a working substance—typically a gas—undergoes various transformations (such as expansion, compression, heating, and cooling) that cause it to absorb and release energy.