The next important part of the heat pump is condenser. The function of the heat pump is to heat the room, and it is the condenser that produces the heating effect inside the room. The main purpose of the refrigerator is to cool the substance or materials and this effect is produced by the evaporator. Thus, while the evaporator acts as the main component in refrigerators producing the cooling effect, the condenser acts as the main component of the heat pump producing the heating effect. In the air conditioner the condenser is placed outside the room which is to be cooled, but in the heat pump the condenser is placed inside the room which is to be heated.
The refrigerant leaving the compressor is at very high pressure and high temperature. This refrigerant then enters the condenser, which is usually made up of copper coil. Due to high temperature of the refrigerant the condenser coil also becomes very hot and it becomes the source of heat which can be delivered inside the room.
There is a fan or the blower behind the condenser coil that absorbs the room air or atmospheric air and blows it over the hot condenser coil. As the air is passed over the condenser coil, it gets heated and the heated air flows to the room making the room hot. The air is absorbed continuously by the fan and the hot air is thrown into the room keeping it at temperature much higher than the atmospheric temperature. There are two types of fans that can be used with the condenser coil: forced fan and induced fan.
Since the air passing over the condenser absorbs the heat from the condenser, the temperature of the condenser and the refrigerant inside it reduces. The refrigerant leaves the condenser at high pressure, but medium temperature in partially liquid state and partially in the gaseous state. It then enters the next important part, the expansion valve or capillary tube.