heat pump is a compression refrigeration system that can reverse the circulating flow of refrigerant in order to add heat or remove heat from a conditioned space, depending on its mode of operation. Heat is absorbed by one coil in one location and released by another coil in another location. In this way, heat pumps are similar to standard comfort cooling systems. However, unlike comfort cooling systems, heat pumping to heating. A flow of refrigerant in order to change their operation from cooling to heating. A reversing valve controls the direction be defrigerant flow through a heat pump's refrigerant circuit. The direction of refrigerant flow determines whether the heat pump heats or cools a conditioned space. When the refrigerant flow is reversed, the coil that previously functioned as an evaporator begins functioning as a condenser. The other coil, which functioned as a condenser, now begins functioning as an evaporator. Heat pumps can use a variety of system arrangements and distribution methods. These can be found in residential, commercial, and industrial applications.