The Second Law of Thermodynamics

The second law of thermodynamics states that heat transfer occurs spontaneously only from higher to lower temperature bodies.

In thermodynamics, a heat engine is a system that performs the conversion of heat or thermal energy to mechanical work.

The Carnot cycle is the most efficient cyclical process possible and uses only reversible processes through its cycle.

A heat pump is a device that transfers heat energy from a heat source to a heat sink against a temperature gradient.