A HEAT PUMP is a device that can pump thermal energy either into (heating) or out of (cooling) an enclosed space, for example, a house.
The basic components of a heat pump are:
working fluid (refrigerant)
condenser (inside coil)
expansion valve
evaporator (outdoor coil)
compressor.
The system is designed around the concept of latent heat of vaporisation. Thermal energy from the outside atmosphere is used to boil the working fluid (outdoor evaporator coil). The vapour produced is then allowed to condense (inside condenser coil), releasing thermal energy to the air inside the house.
A REFRIGERATOR is a device that is used to remove heat through the use of work. A refrigerator is a type of heat pump that uses the evaporation of a liquid.
A HIGH PRESSURE GAS leaves the compressor and flows through the heat sink thus becoming a HIGH PRESSURE LIQUID. As it passes through the capillary (expansion valve) it becomes a LOW PRESSURE LIQUID, as it passes through the fridge compartment it evaporates and becomes a LOW PRESSURE GAS then enters the compressor and the cycle repeats.