Antifreeze Measures for Closed Circuit Cooling Tower Coils

When the closed circuit cooling tower operates during cold weather conditions, taking reasonable antifreeze measures is a relatively simple and cost effective way to prevent or reduce icing.

The simplest and most effective way of protecting the heat exchanger coil from freezing is to use an inhibited ethylene or proylene glycol antifreeze. If this is impossible, an auxiliary heat load shall be added on the coils and minimum flow rate must be maintained in the coil at the same time so that the water temperature will not drop below 10 °C when the cooler is shut down.
If an antifreeze solution is not used in the coils, the coil must be drained immediately whenever the pumps are shut down or fluid in the coils stops flowing. This can be achieved by having automatic drain valves and air vents in the piping to and from the cooler. Cares must be taken to ensure that the piping is adequately insulated and sized to allow the water to flow quickly from the coil. This protection method shall be used only in emergency situations. It is neither a practical nor recommended method of freeze protection. Coils shall not be drained for an extended period of time as the pipe inside may be corroded easily.
When the unit operates in cold weather conditions, some type of capacity control is generally required to keep water temperature from dropping below 10 °C. Operating dry with a remote sump is an excellent way of reducing the heat rejection capacity of the cooler at low temperatures. Other methods of capacity control include two-speed motors, variable frequency driving and fan on/off. These methods can be used individually or in combination with dry/remote sump operation.

Taking the above measures can effectively avoid the coils of the closed circuit cooling towers from freezing. In this way, it not only extends the service life of the cooling towers, but also saves the operation costs.

What Measures Are Taken to Prevent Closed Circuit Cooler Coils from Freezing?