When purchasing industrial water chillers for your industrial applications, a wrong system type can lead to unstable cooling, higher costs, and unexpected downtime. In this article, we break down how closed loop chillers function and why they are widely preferred, helping you make more efficient cooling decisions.
What Is a Closed Loop Water Chiller?
The closed loop water chiller system is a type of circulating cooling system. It transports the coolant (usually water or a water-ethylene glycol mixture) through a sealed and independent circuit, removing heat from the process or your equipment.
Core Components of Closed Loop Water Cooling System
Essential Components
Components in Water Circuit
- Pump
The water pump is used to make coolant flow in the circulating pipeline. It must have sufficient pressure to overcome the resistance caused by water blocks and long-distance pipeline transportation.
- Heat Exchanger
A heat exchanger is used to transfer the heat from the coolant to air or a secondary water source. There are plate type and shell and tube types. In an air-cooled chiller, its fans blow over thin metal sheets (usually copper or aluminum) to dissipate the heat.
- Expansion Tank
The expansion tank is a sealed liquid storage container that can contain the liquid when it is thermally expanded, and the tank can also prevent air from entering the main pipeline of the cooling system.
- Insulated Water Tank
In a closed-loop water cooling system, an insulated water tank is a water tank with an insulating layer. It is used to store the coolant and reduce its heat exchange with the external environment.
Components in Refrigeration Circuit
- Compressor
The power source of the refrigeration system.
- Condenser
A heat dissipation component.
- Evaporator
The place where the two circuits exchange heat.
- Expansion Valve
A throttling device that instantly reduces the pressure and temperature of the high-pressure refrigerant.
Ancillary Control Components
- Coolant
The coolant in a closed loop glycol cooling system is always composed of purified water and glycol with inhibitory properties. Such a mixture can provide anti-freezing protection and prevent internal corrosion.
- Filtration System
With a filtration system in your closed-loop water system, suspended solids and other impurities can be prevented from entering.
- Sensors
There are various chiller sensors for different functions. They ensure the operation of thermometers, flow meters, and pressure switches of your closed-loop cooling systems. They can monitor the operating conditions of your chiller and trigger alarms or shut down the system in case of leakage or pump failure.
Typical Applications of Closed Loop Water Chillers
Because of excellent sealing properties, the closed-loop water system is widely applied in high-end machinery. Usually, typical applications include medical and healthcare, data centers and IT, industrial manufacturing, and energy and utilities.
Healthcare
You can use closed loop water cooling systems to cool high-tech diagnostic and therapeutic devices, preventing overheating, including imaging equipment (such as MRI, PET, CT, etc.), linear accelerators used in radiotherapy, gene sequencers, and analytical testing equipment.
They can also provide a stable temperature environment for blood banks, vaccines, and organ preservation.
IT (Intelligent Technology)
The closed loop chiller system is an ideal choice for controlling the temperature of high-density computing technology servers. It can not only manage the large amounts of heat but also avoid significant consumption of local water resources because it uses a fixed volume of fluid.
Precision Industrial Manufacturing
Applying closed loop water coolers can help you protect expensive machinery stably.
A closed loop chiller system can provide high-purity, precision cooling for injection molding, plastic processing, and chip fabrication. In metalworking, you can use a closed water system to cool CNC spindles, EDM machines, and laser cutting equipment. It can also manage the temperature for breweries, wineries, and food processing plants.
Energy and Utilities
Power plants and the renewable energy industry always use a closed cooling water system. In nuclear facilities, redundant closed loops can provide crucial backup cooling functions. What’s more, closed loop water chiller systems can provide cooling for bearings, lubricants, and air compressors in power plants, and provide centralized chilled water systems for large commercial buildings and government facilities.
Common Problems of Closed Loop Water Chillers
- Insufficient Cooling
The dust accumulation in the condenser can lead to frequent shutdown of your compressor, lowering your cooling capacity. To avoid this, you can clean the condenser regularly and keep good ventilation.
- Circulation Obstruction
If you use poor-quality antifreeze or if impurities are mixed when replenishing water, there may be sediment. You can regularly inspect and clean the Y-type filter and strictly use distilled water or deionized water to prevent obstruction.
- Water Quality Deterioration
If water is not replaced for a long time, the ion concentration increases. This may cause internal electrochemical corrosion or leakage. So it is recommended that you replace the circulating water every 3-6 months.
- Condensation
When the water temperature is set much lower than the indoor environmental dew point temperature, there may be condensation on the equipment pipes and the surfaces of the cooled components. This can cause short circuits. It’s better for you to set the water temperature to 3-5℃, and you can add insulation cotton to the exposed cold water pipes as extra protection.
- Pump Seal Leakage
Operating the pump in a water-deficient state for a long time (dry running) will wear the mechanical seal of your pump. The liquid level sensor can automatically cut off the power when the water level is low, so you need to ensure it is always working properly.
Besides, before starting, it is necessary for you to confirm that the system is fully filled with water and all air has been discharged.
Closed Loop vs Open Loop Chiller
Generally, the open-loop chiller usually requires a lower initial cost, but it needs stable water availability. Although the above problems may occur, a closed loop water system still has obvious advantages in long-term efficiency, water savings, and system reliability in comparison.
You can read the following chart to get more details.
| Comparison Aspect | Closed Loop Water Chiller | Open Loop Water Chiller |
| System Design | Sealed system with recirculating water | Open system exposed to the external environment |
| Water Consumption | Low (water is reused in a closed circuit) | High (continuous water loss and replenishment) |
| Cooling Efficiency | More stable and consistent over time | Can fluctuate due to contamination and evaporation |
| Temperature Control | Precise and stable | Less stable, affected by external conditions |
| Maintenance Requirements | Lower (less scaling, fouling, and contamination) | Higher (frequent cleaning and water treatment needed) |
| Risk of Contamination | Very low | High (risk of algae, debris, scaling) |
| Operating Cost | Lower long-term cost due to efficiency and reduced maintenance | Higher long-term cost due to water usage and maintenance |
| Initial Investment | Higher upfront cost | Lower upfront cost |
| System Lifespan | Longer (less internal wear and corrosion) | Shorter (more exposure-related damage) |
| Typical Applications | Industrial processes, laser cooling, food processing, and medical equipment | Cooling towers, HVAC systems, and large-scale water circulation |
How Does a Closed Loop Chiller Work?
The working principle of a closed loop water system is to continuously move heat away from your equipment and dump it into the atmosphere. This is completed by two cycles: the Water Loop and the Refrigeration Loop.
The Water Loop
The main function of the water loop is to move the heat.
Heat Absorption
In the water loop, the cold water is pumped from the chiller into your equipment. During this process, the water absorbs waste heat and cools your machine, so the water is warmed.
Return
Warm water flows back through the sealed pipes to your chiller evaporator.
Cooling
In the evaporator, the warm water transfers its heat to the cold refrigerant and is cooled again. Then the cooled water is pumped back into your equipment.
The Refrigeration Loop
Different from the water loop, the refrigeration loop is used to eliminate the heat, which is responsible for achieving the actual cooling effect.
Compression
The compressor compresses the refrigerant gas, making it extremely hot and under high pressure.
Condensation
This hot and high-pressure gas flows through the condenser. Here, fans blow air over the tubes of the condenser, discharging the heat into the external air. So the refrigerant returns to a liquid.
Expansion
When the liquid refrigerant passes through the expansion valve, the pressure drops instantly, and the refrigerant become extremely cold
Evaporation
Then, a cold refrigerant enters the evaporator, absorbs the heat carried by the returning warm water, and becomes gas, which is ready to enter the compression again. Finally, a new cycle starts.
Key Benefits of Closed Loop Water Chillers
Sustainability
Open water cooling systems always cause a large loss of water during operation, but the closed-loop water cooling system is different. It only needs to inject the liquid one time. The liquid will be recycled infinitely. This can significantly reduce your water bills.
Internal Cleanliness
In a closed loop cooling system, the coolant never comes into contact with the external air. Therefore, there’s no sunlight or oxygen to promote the growth of living organisms.
In addition, in an open system, evaporation leaves behind scale (calcium and minerals) that can clog the pipes. While the closed-loop system can keep internal cleanliness, ensuring a stable efficiency.
Lower Maintenance Costs
The maintenance of a closed loop chilled water system is very easy, because you do not need to clean dust, pollen, or bird debris collected by the open tower with disinfectants or softeners. You only need to regularly check the quality of the liquid.
Operation in Sub-Zero Environments
In a low-temperature environment, if an open cooling tower is not being drained or heated sufficiently, it will freeze and crack. In comparison, the closed-loop cooling tower or chiller can operate in a temperature range of -20℃ with a glycol mixture. This enables facilities in cold climates to use ambient cold air for cooling, largely saving energy.
Pressure Stability
Compared to open systems, which operate based on gravity or variable municipal water pressure, closed loop cooling systems maintain pressure through pressurization and balancing. This ensures a consistent flow rate for your equipment.
Zero “Blowdown” Waste
Closed loop water system is very suitable for applications with strict wastewater discharge permit requirements and weak drainage infrastructure. However, if you use open-loop cooling systems, you have to discharge wastewater regularly.
Key Factors When Choosing a Closed Loop Water Chiller
When choosing a closed-loop cooling chiller system, there are multiple factors that you need to take into consideration. The following five are the most important ones you should care about.
Cooling Capacity
The cooling capacity is the most basic factor you need to have a clear recognition of. To calculate a chiller’s capacity, you have to calculate the total heat generated (BTU/hr or kW). It is recommended that you ask professionals to make a strict measurement and calculation.
If your closed loop water chiller is placed in a factory without air conditioning or outdoors, an increase in environmental temperature will reduce the cooling efficiency. This is what you need to take into consideration. And do not forget to add a 20% – 30% safety margin at last to deal with future equipment upgrades.
Flow Rate and Pressure
The flow rate decides whether your closed loop water system has the power to “push” the water to complete the refrigeration cycle. If the flow rate is too low, the heat cannot be removed in time, and your equipment will become locally overheated.
Besides, insufficient pressure is the main cause of many industrial laser machines stopping operation. If the internal pipes of your equipment are very narrow or the pipeline is very long, you may need a high-head pump to overcome the resistance.
Temperature Stability
Different applications, including hydroponic greenhouse project, have different requirements for temperature stability and precision.
An ordinary closed-loop chiller can control the temperature from ±1℃ to 3℃, suitable for applications such as injection molding machines, general hydraulic systems, etc.
A more precise closed-loop chiller can control the temperature from ±0.1℃ to 0.5℃, suitable for laboratory analyzers, medical MRI, or high-end laser cutting machines. In these applications, a higher water temperature fluctuation can lead to mistakes like data drift or cutting burrs.
Material Compatibility
The internal materials of the chiller must match your equipment, or it may not maintain pure water.
If your equipment requires high-purity water or demineralized water, you have to choose chillers with stainless steel, copper, or high-performance plastic pipings. Meanwhile, you should also ensure that the seals and pump bodies of the chiller are compatible with the antifreeze fluid you plan to use.
Condensing Type
Air-cooled chillers and water-cooled chillers have different condensing types.
An air-cooled condenser has a simple installation. It dissipates heat through a fan. So it is suitable for large spaces with good ventilation.
A water-cooled condenser is small and quieter, but it dissipates heat through the cooling tower in the factory area, so you need to connect an additional circulating water system in your factory area.
FAQ
Can a Closed-Loop Chiller Be Customized for Specific Industrial Requirements?
A good supplier can provide flexible closed loop cooling system custom configurations and support different voltages, sizes, control systems, and temperature control accuracy according to your specific requirements.
What are the Installation Requirements for a Closed Loop Water Chiller?
To install a closed loop water chiller, you should prepare a space with a good ventilation system, a reliable power supply, and a solid and level ground. You also need to prepare purified water and equipment to complete an initial fill and expel.
What is the Typical Lifespan of a Closed Loop Water Chiller?
Typically, a well-maintained closed loop water chiller can last for 10 to 15 years. If it operates under low-load conditions, the lifespan can even be extended to 20 years.
Can Closed Loop Chillers be Integrated with My Existing Cooling Systems?
Yes, you can let the closed-loop chiller operate in parallel with your existing cooling equipment. It can take on the cooling load, reducing the pressure on your main system. Or you can install the closed-loop system before the existing mechanical chiller, so it can lower the temperature of the coolant before it reaches the main unit, significantly reducing the energy required for the second stage of cooling.
How Much Does a Closed Loop Water Chiller Cost?
From hundreds to tens of thousands, the prices of closed loop water chillers vary greatly. It’s decided by lots of factors, including the chiller’s temperature control accuracy, pump specification, material requirements, and various additional features, such as remote communication, explosion-proof design, outdoor rainproof enclosures, etc.
Final Thoughts
Understanding the closed loop cooling system and its working principle is crucial for selecting a system that can provide stable performance and long-term efficiency for your industry. With over 20 years of experience, Chillerone always provides a mature closed loop chilled water system design and flexible configuration. Contact us. We promise to customize cooling solutions that meet your actual industrial needs.
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