Towers with internal and external heat exchangers

Cooling towers work in two main ways – Open Circuit and Closed Circuit

Open Circuit

In anOpenCircuitTowerthe water enters the tower through nozzles and onto the filling material.  There, water is cooled by a flow of air distributed by blowers.  The water then arrives cold to the pool of the cooling tower and gets transferred to the consumer.

An open circuit with external heat exchanger performs the same as a regular open circuit but instead of transferring the water to the consumer the water is transferred to and adjacent hear exchanger.  There is no direct water contact with the water of the tower and the water of the consumer but a transfer of heat as needed.  The water form the heat exchanger returns cold to the consumer and warm to the tower.

Closed Circuit

In a Closed Circuit Tower there is a complete separation of the water of the tower and the water from the consumer.  The water arriving form the consumer enters a heat exchanger made from Copper and later, cooled by both water sprayed form the nozzles and air from the blowers before being returned to the consumer.

The advantages of  using an external or internal heat exchanger is the security of the water quality that is returned to the consumer and that the cooling compartments and machinery will not be clogged by hard water or other causes from the water arriving from the tower.  Also, in areas where the temperature is below 0 degrees Celsius, there is a concern that the water arriving at the consumer will freeze; thus closed circuit is used only with the addition of antifreeze and other chemicals that will mix with the water of the heat exchanger.  In this case the usage of an internal heat exchanger is need only.  Most towers used inEuropeare of this kind.