What is a Heat Pump system?

A heat pump transfers thermal energy from one location, which is at a lower temperature to another which is to a higher temperature. The “reversible-cycle heat pumps” are designed to work in either thermal direction, it simply operates in a way that changes which coil is the condenser and which coil is the evaporator, rather than physically turn it around. This function is normally achieved by a reversing valve. In HVAC applications, the term heat pump refers to a reversible vapor-compression refrigeration system that includes a reversing valve and optimized heat exchangers so that the direction of thermal energy flow may be changed without loss of efficiency. A heat pump through the refrigerant absorbs heat as it vaporizes and releases the heat when it is condensed. It uses the evaporator to absorb heat from the room and rejects it outside through the condenser. The key component that makes the difference between a heat pump and a cooling only air conditioner is the reversing valve, which allows the change of the refrigerant’s flow direction.