What is the Function of the Condenser in the Refrigeration System of Refrigerated Air Dryers for Air Compressors

What is the function of the condenser inside the refrigeration system of a refrigerated air dryer?

Condensers and evaporators are collectively referred to as refrigeration heat exchangers, which are essential supporting components for refrigeration compressors. 

Within a refrigeration system, the refrigeration compressor is generally defined as the main unit, while heat exchangers are auxiliary equipment.

During the refrigeration cycle of a refrigerated air dryer, the condenser dissipates heat to the surroundings and condenses refrigerant into liquid. 

High-temperature and high-pressure discharge gas from the compressor flows into the condenser. It transfers all absorbed heat (heat absorbed in the evaporator, 

heat generated during compression by the compressor, and ambient heat absorbed when refrigerant travels through pipelines) to the surrounding medium, namely air or water, for heat removal.

Refrigerated Air Dryer for Air Compressor
The process in which compressor discharge gas condenses into liquid inside the condenser generally consists of three stages: desuperheating, condensation and subcooling.
The superheat of refrigerant superheated vapor is released until the refrigerant reaches the condensing temperature and turns into saturated vapor. This phase is the desuperheating stage.
Latent heat of condensation is released at a constant condensing temperature, converting saturated vapor into saturated liquid. This phase is the condensation stage.
Additional sensible heat is removed from the liquid to turn saturated liquid into subcooled liquid. This phase is the subcooling stage.
Heat of condensation accounts for the largest share of the total heat load of the condenser.
Common Types of Condensers
Condensers are divided into two main categories based on cooling methods:
Water-cooled Condenser

In water-cooled condensers, heat released by refrigerant is carried away by cooling water. Cooling water can adopt once-through flow or circulating circulation. 

A cooling tower or chilled water tank is required for circulating water systems. Typical structures of water-cooled condensers include shell-and-tube type and double-pipe type.

Air-cooled Condenser

In air-cooled condensers, ambient air removes heat released by refrigerant. They are mainly constructed with multiple serpentine coil assemblies. 

Air features poor heat transfer performance, so fins are installed on serpentine coils to expand the heat transfer area on the air side. Fans are also deployed to accelerate air flow and improve heat exchange efficiency.

Both types of condensers are widely adopted in refrigerated air dryers. Small-size dryers mostly use air-cooled condensers, while medium and large units are mainly equipped with water-cooled condensers.