Cooling towers are a prominent feature on the British skyline. These huge, convex structures punctuate both rural and urban landscapes, and have done so for decades.

Nevertheless, many people are still unaware of what cooling towers are and the role that they play in industry. If you’re in the dark about cooling towers, here’s a quick guide to how they work.

What are cooling towers?

Cooling towers are often found in power stations, factories and chemical plants. Their basic function is to remove excess heat. In a chemical plant, for instance, certain processes may generate excess heat. Using a heat exchanger and cool water passed through a cooling tower, this is removed.

In this way, cooling towers help control the temperature of a workplace, as is required by law. However, cooling towers may also be instrumental in industrial processes themselves. For example, electricity is generated in a power station when steam passes through a turbine. In order to maintain this cyclical process, the steam must condense before passing into the boiler and then back through the turbine. Condensation happens in a heat exchanger, which requires water cooled through a cooling tower.

The large convex cooling towers seen prominently in the UK are called natural draft towers. The height of these towers – which often exceeds 100m tall – creates the conditions for a natural process by which air is lifted and then condensed into water droplets as it falls back down. So the large smoke-like plumes often seem emanating from these towers are not smoke at all, but water vapour.

Another type of cooling tower found in industry is the forced draft tower. These contain fans which force air through the tower, in order to condense it into water. Forced draft towers are typically more box-shaped and much shorter than natural draft towers, and therefore are often less noticeable.

Smaller cooling towers

Although they are most commonly found in industry, cooling towers have many other applications too. For instance, smaller forced draft towers may be found on office buildings, as a temperature control mechanism. And in a domestic setting, cooling towers are most frequently found in air conditioners, to get rid of hot air.

Although cooling towers are often a permanent fixture on factories or offices, temporary cooling tower rental is also widespread. Hired cooling towers are particularly useful if permanent fixtures have broken or are undergoing maintenance. They can also be used if a factory or plant needs extra capacity to supplement its existing cooling infrastructure.