Heat pump and refrigeration cycle
At the start of the cycle, the refrigerant enters the compressor as a low pressure and low temperature vapor. The pressure is then increased and the refrigerant leaves as a higher temperature and higher pressure gas. This hot pressurized gas then moves through the condenser coil, where it releases heat to the area as it cools and condenses completely. The cooler high-pressure liquid next passes through the expansion valve which lowers the pressure suddenly and causes the temperature to drop a lot. The cold low pressure mixture of liquid and vapor next travels through the evaporator coil where it vaporizes completely when accepts heat from the area around it before returning back to the compressor as a low pressure low-temperature gas to start the cycle again.