How do Cooling Towers Operate in Cold and Sub-Zero Weather

Suppose you asked most operators or a layman with a rudimentary understanding of how a cooling tower works. In that case, they could likely tell you that a cooling tower’s main purpose is to lower water temperature within the tower to its lowest possible point so the cooling tower can cool the air where it is working, whether it be a smaller industry, such as a hospital or school, or a larger one, like industrial plants and factories. However, many people wonder how cooling tower operation in freezing weather can occur because if the water freezes, then, of course, the tower would cease to function properly.

Operating Cooling Towers in Winter

Cooling towers in some industries must operate year-round, and because of this, they must operate in winter. However, many climates have subzero temperatures.

A cooling tower with a wet-bulb temperature exposed to temperatures below the freezing point (32°F/0°C) for more than 24 hours will not be exposed to a daily freeze-thaw cycle and can be dangerous for the tower’s operation.

Generally, the lowest temperature you want your cooling tower to reach is 32°F, and this wouldn’t be optimal for a sustained period. Still, cooling towers operate in Montreal, Canada, which regularly see temperatures of 5°F(-15°C). So, what prevents the water in a cooling tower from freezing in cold weather?

Many cooling towers that work year-round are made for industries such as data centers, which have a high load factor.

Knowing this from the outset, the cooling tower’s size and design would have been oversized to begin with, allowing the operator to run the tower in economizer mode in colder weather. This can also boost cooling tower efficiency in winter.

Ensuring Smooth Cooling Tower Operation in the Cold

The colder the weather is outside, the more vigilant you must be with keeping an eye on the tower. The first thing you must do is always maintain the heat load.

Without doing so, water can end up icing over, or the water will become the same as the wet-bulb temperature, which will also be exceedingly cold.

Also, even if your system is automated, regular visual inspections should be made of cooling tower operation to ensure everything is in smooth working order. This should be performed at least once a shift during below-freezing temperatures. You may even want to inspect more often if the weather is particularly cold.

If you find that you cannot maintain your heat load and ice begins to form, you can bypass operating water and direct it to the cold water basin. Do not let water flow back up again until it has arrived at the target heat load temperature.

It is natural to have some icing on the cooling tower during subzero temperatures, which will not harm the cooling tower.

While they have different designs, both counterflow and crossflow cooling towers experience many of the same issues with icing when the heat load temperature is too low.

The main issue is not to let ice form on the components of the cooling tower, which is why it should be watched. This can cause damage.

What Is the Coldest Temperature a Cooling Tower Can Produce?

Knowing cooling tower temperatures, temperature ranges, and wet-bulb temperatures can help gauge how efficiently your cooling tower is performing. For some industries, cooling is essential year-round because of the heat produced inside large industrial plants.

However, many plant managers are interested in how to increase cooling tower efficiency in summer. To best understand this, you have to know a little about how a cooling tower works in general and what range and approach is.

The coldest temperature that a cooling tower can reach is 4-5° Fahrenheit, higher than the wet-bulb temperature. This is calculated by measuring the water temperature that enters the cold basin and the wet-bulb temperature (this is also known as measuring the approach). Read on to learn more about cooling tower temperatures.

How Does a Cooling Tower Work?

Cooling towers are essentially large systems that cool through evaporation, recirculating water to cool HVAC or industrial process equipment. Without the cooling towers that provide cool water, this expensive equipment would overheat or have to shut down.

Understanding Approach and Range

When speaking of cooling tower temperatures, it’s not quite the same as when you’re discussing what the temperature is outside. Several factors go into measuring cooling tower temperatures, such as its approach and range.

When cooling tower temperature is measured, a psychrometric chart is used to determine the effect of both temperature and humidity. This is used to determine the wet-bulb temperature.

Approach measures the temperature of the water that enters the cold basin and the wet-bulb temperature. This approach can vary inversely with the size of the cooling tower and is typically used as a benchmark to measure the capability of a cooling tower’s cooling. The approach is also directly influenced by the cooling tower’s performance.

Range measures the difference between the water temperature that enters the cooling tower and the water that leaves the cooling tower. For example, if the water going into the tower was 95° Fahrenheit and the water leaving the tower was 85° Fahrenheit, the range would be 10°.

You can use a formula to figure out the efficiency of the cooling tower with the expression μ = (ti – to) 100 / (ti – twb). When you put in the parameters, (95-85) / (95-80) = 66% tower efficiency. In the above example, 80° stands for wet-bulb temperature.

This is why it is important to know how a cooling tower works.

What Are Cooling Tower Temperature Ranges?

The standard wet bulb temperature of a cooling tower is 78° Fahrenheit. However, this is not the highest temperature that a cooling tower can withstand. The water temperature that enters the cooling tower is typically 95° Fahrenheit.

However, cooling tower companies ensure that cooling towers are structurally sound enough to withstand entering water temperatures of 120° Fahrenheit. In some cases, cooling towers can withstand higher temperatures. Still, it’s best to discuss your project with the cooling tower manufacturer beforehand, as you likely will need to use alternative fill materials for the tower to withstand higher levels of heat.

For more information about the installation, repair, and replacement, or maintenance of cooling towers, contact Delta Cooling Towers, Inc. today. We use the latest technology to construct our towers, such as high-density polyethylene, and our towers come complete with an industry-leading 20-year warranty.

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