Respect the cold. Your tower will thank you in July.
When ice forms, panic leads to silence. Silence leads to stagnation. Stagnation leads to a tower that looks less like a heat exchanger and more like a frozen waterfall. A frozen cooling tower cannot be thawed with steam hoses; it must be rebuilt in April.
As ambient temperature drops, the cooling tower’s capacity for heat rejection actually skyrockets. A tower designed to cool 100°F water down to 85°F on a 95°F summer day can easily overcool that same water to 40°F or lower on a 20°F winter night. While this sounds like a performance gain, it leads to the "Ice Paradox": The better the tower performs thermally, the faster it self-destructs structurally. cooling tower handbook
Ice formation begins not at the bottom basin, but at the air inlets—specifically on the louvers and fill. As falling water droplets drift into the sub-freezing air stream, they flash into ice crystals that adhere to the leading edges of the fill. This is called accretion . If left unchecked, an ice bridge will form across the air intake, strangling airflow, collapsing the fill, and ultimately toppling the fan deck.
From the Cooling Tower Handbook, 4th Edition Respect the cold
For nine months of the year, the cooling tower is the unglamorous workhorse of the industrial plant—loud, wet, and largely ignored. But when the mercury dips below 32°F (0°C), this same piece of equipment transforms overnight into the plant’s most vulnerable asset. Winter operation is not about efficiency; it is about survival.
If you see ice, do not shut down. Increase heat load. Increase water flow. Do not stop the fan unless you intend to scrap the cell. Silence leads to stagnation
Here it is, the line you should memorize and stencil onto the tower control panel: