Evaporative Condenser – Construction and Working , Advantages

An evaporative condenser is a condenser integrated into a cooling tower which rejects the latent heat of condensation of refrigerant (Ammonia/Freon) through a coil to the surroundings by means of evaporation.
Water sprayed onto the coil exchanges heat with the refrigerant. A small quantity of water is evaporated into the air thereby cooling the remaining water cascading to the basin at the bottom. Post evaporation the saturated air passes through the drift eliminators and then forced out using a fan.

Construction And Working Of Evaporative Condenser :

In evaporative condensers, both air and water are used to extract heat from the condensing refrigerant. Figure shows the schematic of an evaporative condenser. Evaporative condensers combine the features of a cooling tower and water-cooled condenser in a single unit. In these condensers, the water is sprayed from top part on a bank of tubes carrying the refrigerant and air is induced upwards. There is a thin water film around the condenser tubes from which evaporative cooling takes place. The heat transfer coefficient for evaporative cooling is very large. Hence, the refrigeration system can be operated at low condensing temperatures (about 11 to 13 K above the wet bulb temperature of air). The water spray counter current to the airflow acts as cooling tower. The role of air is primarily to increase the rate of evaporation of water. The required air flow rates are in the range of 350 to 500 m3/h per TR of refrigeration capacity.

Diagram of Evaporative Condenser

Evaporative Condenser construction and working

Benefits Of Evaporative Condenser

Continuous coil without welded joints
Robust corrosion resistant structural material for long life
Large diameter laminar flow nozzles for clog free operation.
Air Flow – Parallel at coil side and cross at fill side for efficient heat transfer
Optimized spray water flow to coil for maximum heat transfer