When we think about cooling equipment, we usually imagine the typical open-circuit cooling tower—an evaporative cooler that operates through direct contact between air and water. However, at Torraval, we understand that this is not always the optimal solution for public and industrial spaces. In some projects, it is preferable to avoid direct contact between air and water (hydraulic separation), making a closed-circuit cooling tower the ideal choice.
What are closed-circuit cooling towers?
Let’s take a look at what closed-circuit cooling towers are and how they work. Basically, they utilize the same evaporative principle as open-type coolers: the forced evaporation of a minimal amount of water reduces the temperature of the main water mass.
A closed-circuit cooler has two separate fluid circuits:
- One in which the fluid circulates inside smooth tube coils (primary circuit).
- Another where recirculating water (secondary circuit) is sprayed over the coils.
The contact between air (driven by fans) and the sprayed water provides evaporative cooling similar to that of an open-circuit cooling tower, with the key difference that the process fluid is never in direct contact with the air (hydraulic separation).
Three reasons to choose Torraval’s closed-circuit cooling towers
Now that we know the basic elements, we can better understand the 3 advantages of Torraval’s closed-circuit cooling towers:
- No contamination of the primary circuit. Many cooling processes require the process fluid to remain uncontaminated by the external environment; for example, this is crucial for most food production processes. Our closed-circuit cooling towers ensure this need: the coils separate the process fluid from the ambient air driven by the fans, keeping it clean and uncontaminated in a closed loop.
- Reduced risk of freezing. Since the process water circulates inside the heat exchange coils and never comes into contact with air, glycol can be added to lower the fluid’s freezing point. This is a major advantage, especially in cold climates (such as Scandinavian countries, Russia, Canada, etc.) where temperatures frequently drop below zero.
- A simpler system. A closed-circuit cooling tower from Torraval can be an alternative to a system composed of an open-circuit cooling tower and a heat exchanger. This offers several benefits:
- Simpler plant design.
- Smaller footprint.
- Higher thermal efficiency.
Cooling for different needs
There is no “best” cooler in absolute terms, meaning that a closed-circuit cooler is not always preferable to other solutions. However, certain project requirements can strongly support its use.
At Torraval, we have listed some advantages (related to the preservation of the cooling liquid) that make our closed-circuit cooling towers a reliable choice in certain situations and based on specific project requirements.