Cooling towers are used almost everywhere you turn. From data centers to office and residential high-rises to industrial manufacturing, oil refineries, HVAC air-conditioning, refrigeration, and electric power generation, cooling towers are critical to maintaining proper operating temperatures of these facilities.
A cooling tower’s primary function is to throw off excess heat into the surrounding air through the evaporation of water (wet cooling towers) or rely on air alone to dissipate the excess heat (dry cooling towers).
As our concern is preventing the supply lines to wet cooling towers from freezing, we’ll focus on pipe freeze protection for wet evaporative cooling tower systems in this article.
Wet cooling towers work by cooling the warm water generated by HVAC chillers, HVAC condenser pumps, machinery, or heated process material to a temperature lower than the ambient air dry-bulb temperature.
To accomplish this, the cooling tower routes cool water through the area that is generating heat to absorb the excess heat.
The heated water is then passed to the top of the tower where it is sent back down over a fill material.
As the hot water passes down over the fill material, ambient air passes (either naturally or mechanically) upward over the flow of hot water.
The temperature difference between the two causes a small amount of water to evaporate.
The energy used to evaporate that water is taken from the total volume of hot water causing it to cool back down to its original temperature.
The water is then combined with cool water to replace the evaporated water and recirculated back through the system to cool the heat-generating components again through the water supply lines.
Where cooling towers can experience freezing is when the cool water supply lines or recirculated cool water lines are exposed to freezing temperatures.
While wrapping with heat tape and insulation can work that may be difficult or impossible in tight spaces that are exposed to wind chill or freezing temperatures.
As long as the exposed area is fairly straight, a better solution would be to install an internal pipe heater from the start of the freezing area to a point in the structure that stays above freezing consistently.