Let's discuss condensers in refrigeration units. They can be broadly classified into two categories based on their cooling method:

1. Water-cooled condensers: In this type of condenser, the heat released by the refrigerant is carried away by cooling water. The cooling water can flow through continuously or be recycled. When using circulating water, a cooling tower or chilled water tank is required. Water-cooled condensers have shell-and-tube and coaxial tube structures.

2. Air-cooled condensers: In this type of condenser, the heat released by the refrigerant is carried away by ambient air. Its structure mainly consists of multiple sets of serpentine coils. Because air has poor heat transfer properties, fins are usually added to the outside of the serpentine coils to increase the heat transfer area on the air side. A fan is also used to accelerate airflow and further enhance the heat transfer effect on the air side.

Both types of condensers are widely used in refrigerated air dryers. Small refrigerated air dryers primarily use air cooling, while medium and large refrigerated air dryers mainly use water cooling.