Closed circuit cooling towers are becoming more and more popular in the cooling industry due to their efficient two-part system. As more of these pieces of equipment continue to be implemented into cooling systems across the nation, it has become increasingly more important to have proper testing and acceptance test codes. In this blog, we’ll discuss:

• What are closed circuit cooling towers?

• How do they operate?

• Testing procedures

What Are Closed Circuit Cooling Towers?

Closed Circuit Cooling Towers closely resemble open circuit towers in both form and function. The main difference is that closed circuit towers contain two separate fluid circuits:

• An external circuit where recirculating water is exposed to the outside surface of a tube bundle/heat exchanger

• An internal circuit where cooled process fluid is circulated inside the tubes of the tube bundle/heat exchanger

How Do They Operate?

Closed circuit cooling towers operate very similarly to open cooling towers, except that the rejected heat load is transferred from the process fluid to the ambient air through a heat exchange coil. The coil isolates the process fluid from the outside air, keeping it clean and contaminate free in a closed loop. 

Testing Procedures

To ensure your closed circuit cooling tower is functioning properly, it’s important to undergo routine testing. These test include the following procedures:

• Testing properties of the process fluid

  • If properties differ from the specified contract documents by 10% or more, the test will not be considered valid

• Checking flow rate of the process fluid

  • A pitot tube is used to test the flow rate of your process fluid to ensure that he system functions properly and your metal doesn’t corrode from the fluid

• Determining temperature and flow rate of recirculating water in the external water circuit 

• Checking overall condition of equipment and amount of fouling

How Can CTI Assist With Your Cooling Tower Needs?

Cooling Technology Institute has published a plethora of papers about various cooling topics. CTI is also an advocate in promoting the use of environmentally responsible Evaporative Heat Transfer Systems (EHTS), cooling towers, and cooling technology for the benefit of the public. Additionally, CTI is an independent, third-party thermal performance testing to help participating manufacturers and owners/operators achieve the best performance from their cooling towers. Visit our website today for more information on cooling technologies!