A condensing unit is a part of a refrigeration or air conditioning system that cools and condenses refrigerant vapor into liquid. It does this by using the pump action of a compressor to compress and raise the pressure of the low-pressure vaporized refrigerant coming from the system’s evaporator. As the refrigerant gas is compressed, it heats up and is then sent to the condensing unit, where it is cooled down by a fan blowing air over a coil containing the high-pressure refrigerant. This cooling process causes the refrigerant to condense back into a liquid. The liquid refrigerant then flows through a metering device, which reduces its pressure and temperature before it enters the evaporator to restart the cycle. The condensing unit is typically located outside a building or room, and is responsible for rejecting the heat absorbed by the evaporator, making it an essential component in refrigeration and air conditioning systems.