Closed‑Loop Cooling Systems: Expert Insights for Industrial Applications

Determining whether an open-loop cooling system or a closed-loop cooling system is best for your application can be tricky; you need to take the application’s specific cooling requirements, as well as the project’s budgetary, environmental, and physical constraints into consideration when making this decision. The first step in the process, however, is becoming acquainted with how each system works! The first system type we’ll be exploring is the closed-loop cooling system.

What is a Closed Loop Cooling System?

A closed-loop cooling system is a cooling system that uses a liquid coolant (which can be water/water-based coolants or oil/oil-based coolants) to exchange heat from the industrial process in a closed-loop setup. In the closed-loop chiller, the coolant is first chilled in a coolant tank, then circulated throughout the process/equipment; during this circulation, the coolant absorbs heat from the application and equipment. Once the coolant reaches the evaporator, this absorbed heat is evaporated, with the liquid coolant then returning to coolant tank to be re-cooled and recirculated throughout the system.

Benefits of Closed-Loop Cooling Systems

The benefits of closed-loop chillers are multifold:

• Precise Temperature Regulation. The sensitive nature of processes and equipment means that being able to regulate the temperature of the coolant (and thereby ensure its ability to effectively absorb heat from these) is vital. Closed-loop cooling systems are adept at maintaining constant temperatures of the coolant liquid, which improves their cooling efficiency.
• Reduced Water Consumption. By recirculating the liquid coolant and not simply using it once (as in a single pass cooling system), you’re reducing the amount of water used for cooling.
• Decreased Environmental Impact. Because closed-loop chillers are a sealed system, you’re minimizing the chance for environmental contamination from contaminants like bacteria, mud, and dust that might otherwise happen with an open-loop chiller system. This also allows your business to avoid any stormwater or wastewater treatment costs, as closed-loop systems don’t discharge the coolant into the environment.

Types of Closed-Loop Cooling Systems

There are three main types of closed-loop cooling systems: closed-loop dry systems, closed-loop evaporative systems, and liquid-to-liquid cooling systems.

1. Closed-Loop Dry (Air-Cooled) Systems. This type of closed-loop system utilizes an air-cooled heat exchanger to release the heat absorbed by the coolant into the atmosphere.
2. Closed-Loop Evaporative Systems. This cooling system employs an evaporative type of heat exchanger and evaporation to remove the heat that has been absorbed by the coolant.
3. Liquid-to-Liquid Cooling Systems. As its name would suggest, liquid-to-liquid cooling systems use heat exchangers to transfer the heat from one coolant to another; typically once the coolant has circulated through the process, it travels to the heat exchanger and then the heat is transferred to the liquid in a cooling tower, body of water, etc.

Want to learn more about Atlas Copco’s portfolio of industrial chillers? Visit us at www.atlascopco.com/industrial-cooling!