The purpose of a condenser in an air conditioner unit is to transform the hot, gaseous, and high pressure refrigerant into a cool liquid form so that it is ready to be used in the evaporator. The condenser does it by removing sufficient heat from the hot gas, to ensure its condensation at the pressure available in the condenser. The rejected heat is shifted into another medium, like water or air, to cool the condenser. The condenser types of an air conditioner depend on how it rejects the heat to the environment. If it rejects it to the air then it is an - air cooled condenser. On the other hand if the heat is rejected to the water, then it is called a water cooled condenser.

Let’s first take a look at the types of water cooled condenser-

Double Pipe Condenser: These have a system of a pipe inserted in another pipe. The pipes are arranged in horizontal position to form a vertical bank. These condensers use a solution of water and ammonia for cooling. The condenser unit is mounted on a wall. A mixture of water md ammonia enters the system through the bottom and goes up through the inner pipe. The compressed refrigerant vapor goes through the top section flowing downward. A counter flow is generated as a result of this. The vapor is cooled by the ammonia mixture.

Double Tube Condenser:This is same as a double pipe condenser. The only notable difference is that these have a tube inside another tube. The refrigerant flows through the annular space between the two tubes.

Shell and Coil Condenser:These condensers have a copper coil that is situated inside a steel shell. Water is circulated through this coil. On the other hand the refrigerant vapor is discharged by the compressor. The water through the coil helps in condensing the vapor that happens outside of the cold tubes. This type of condenser is cheaper. However maintaining these is a big issue. If leakage occurs on the coil, taking it out from the steel shell is not an easy task. The head of the shell requires to be removed for this purpose.

Shell and Tube Condenser: It is same as shell and coil condenser. The only difference is that in this case a large number of tubes are located in a steel shell. Through this tubes water flows. The vaporous refrigerant is discharged around the tubes. The vapor condenses on the exterior surface of the tubes, and drops to the bottom of the condenser. This design provides lots of surface for condensation in a compact space.

The condenser unit of an A/c also has compressor that is used to compress the refrigerant in order to raise it temperature and pressure. There are tubes that move from the condenser unit to the evaporator to conduct refrigerant back and forth.

Capacity of water cooled condensers

The capacity of water cooled condensers depends on three factors - the temperature of the water, the amount of water circulated, and the temperature of the refrigerant gas. The more the difference in temperature between the refrigerant gas and water, the more will be the capacity. This can be achieved by increasing the condensation pressure, or reducing the temperature of the water entering, or by increasing the amount of water to maintain a low water temperature.

There are two types of air cooled condenser. They are tube and fin condenser and plate condenser. In the former the hot refrigerant flows through the tubes which have fins outside. The fins are used to provide additional heat transfer area, which will increase the heat transfer rate. The air is blown over the tube by a fan which is used to cool the refrigerant inside.

The plate condenser are shaped like metallic plates that transfer the heat from the fluid to the air.