subcooling refers to a liquid whose temperature is below its saturation point . As a general rule, all refrigeration systems have a subcooling stage, which can take place both inside and outside the heat exchangers.

In a refrigeration system, subcooling is used to bring the refrigerant from the condenser to the thermostatic expansion valve (VTX) in a completely liquid form.

When exiting the compressor, the refrigerant is in a high temperature and high pressure state. Therefore, upon reaching the condenser, it will absorb the heat and release it to the environment, so that when the refrigerant leaves it, it is in saturated liquid phase and can access the expansion valve thermostatic. If the coolant temperature is lowered one degree, its capacities will increase.

To improve efficiency, a heat exchanger could be used in this phase of the cooling system. When the liquid refrigerant reaches the evaporator, it is subcooled. After this phase, when it returns to the compressor, the refrigerant will go in gaseous form and the process will be repeated.

The use of subcooling leads to potential energy savings . Furthermore, by reducing the flow rate of the refrigerant both in liquid and gaseous state, subcooling allows the use of smaller interconnection pipes .

Subcooling systems
As we mentioned, subcooling occurs in the condenser. There are different types of condensers that use different subcooling systems .

Water-cooled condensers
Pipes are introduced into the condensed liquid through which cooling water circulates, which will reduce the temperature of the liquid.

Air-cooled condensers
A section is added to the condenser that separates the gas and the liquid and where the cooling air will be added.

Evaporative condensers
This type of condenser is used when it is not going to be possible to reuse the absorbed heat, which is eliminated through the evaporation of the water.

In addition to the drop in temperature that occurs in the condenser, the subcooling of the liquid can also occur naturally as it passes through the pipeline.