An industrial chiller is a machine that removes heat from a process and holds it at a precise temperature by circulating a chilled liquid through a closed loop. It uses a refrigeration cycle to cool the fluid, which is then pumped to the equipment, absorbs unwanted heat, and returns to be cooled again — continuously. This guide explains what a chiller is, how it works, its main components, the different types, and where it is used.
What is an industrial chiller?
An industrial chiller is a cooling system that produces and circulates chilled liquid to remove heat from machinery, processes, or laboratory equipment. Rather than cooling the air in a room like an air conditioner, a chiller cools a fluid — usually water or a water/glycol mixture — and delivers it exactly where heat needs to be carried away.
Most industrial chillers are recirculating chillers: the same coolant flows in a closed loop, picking up heat at the equipment and releasing it back at the chiller. This makes the temperature stable and repeatable, which is essential for sensitive processes where even a few degrees of drift can affect quality, accuracy, or yield.
Eldrotec designs and manufactures industrial recirculating chillers ranging from compact benchtop units up to 30 kW systems for demanding production environments, including fully custom configurations.
How does an industrial chiller work?
At its core, a chiller works on the vapor-compression refrigeration cycle — the same principle behind a refrigerator or air conditioner, but engineered to cool a process fluid to a controlled set point. The cycle moves heat away from the coolant and rejects it to the surrounding air or to a separate water supply. It runs continuously in four stages.
First comes compression: the compressor draws in low-pressure refrigerant vapor and compresses it, raising its pressure and temperature. Next is condensation, where the hot, high-pressure refrigerant flows into the condenser and releases its heat — to ambient air in an air-cooled unit, or to a water circuit in a water-cooled unit — and condenses into a liquid. The third stage is expansion: the liquid refrigerant passes through an expansion valve that drops its pressure sharply, causing it to cool rapidly and become a cold, low-pressure mix of liquid and vapor. Finally, in evaporation, the cold refrigerant absorbs heat from the process fluid inside the evaporator. The refrigerant boils into vapor, the process fluid is chilled, and the cycle returns to the compressor to begin again.
Meanwhile, a separate coolant loop handles the user side. A pump pushes the chilled fluid from a reservoir out to the equipment, where it absorbs the machine’s waste heat. The now-warmer fluid returns to the evaporator to be cooled again, while a temperature controller constantly compares the fluid temperature to the set point and adjusts the system to keep it stable.
Because the same fluid recirculates in a closed loop, the chiller can hold a precise, repeatable temperature and keep the coolant clean — unlike single-pass tap-water cooling, which wastes water and offers no real temperature control.
Key components of a chiller
A typical industrial chiller combines a refrigeration circuit with a fluid-handling circuit. The main parts are:
- Compressor — the heart of the refrigeration cycle; it raises refrigerant pressure and temperature to drive heat rejection.
- Condenser — releases the collected heat to ambient air or a water circuit, condensing the refrigerant back to a liquid.
- Expansion valve — drops refrigerant pressure so it cools sharply before entering the evaporator.
- Evaporator — where the refrigerant absorbs heat from the process fluid; this is the point at which cooling actually happens.
- Pump and reservoir — store the coolant and circulate it to the equipment at the required flow rate and pressure.
- Controller — monitors fluid temperature and regulates the system to maintain the set point, often to within a fraction of a degree.
Types of industrial chillers
Chillers are most often grouped by how they reject heat. An air-cooled chiller uses fans to blow ambient air across the condenser, carrying the heat away. Because it needs no external water supply, it is simpler to install and maintain — a strong choice where water is scarce or expensive and where ambient conditions are reasonable.
A water-cooled chiller, by contrast, rejects heat into a separate water circuit, usually connected to a cooling tower. These units tend to be more efficient at higher capacities and perform well in hot environments, but they require water infrastructure.
Eldrotec’s standard PWN and high-precision PWNH chillers are offered in both versions — air-cooled (designated with an A suffix) and water-cooled (a W suffix) — so the heat-rejection method can be matched to the facility. You can see the full lineup on the recirculating chillers page.
Chiller vs cooling tower vs air conditioner
These three are often confused because they all move heat, but they do different jobs. An industrial chiller cools a process fluid and can hold it well below ambient temperature, to a precise set point. A cooling tower only rejects heat from water by evaporation, and cannot cool below the ambient wet-bulb temperature. An air conditioner cools room or building air for comfort, not for process precision.
In practice a chiller and a cooling tower often work together: in a water-cooled setup, the cooling tower rejects heat from the chiller’s condenser, while the chiller delivers the exact temperature the process demands. A chiller can reach temperatures far below what a tower alone can achieve — which is why precision processes rely on chillers rather than towers.
Coolant fluids and glycol
Plain water is an excellent heat-transfer fluid, but it freezes at 0°C and can cause corrosion or biological fouling. When a process must run cold — or when the chiller sits in a cold environment — the coolant is switched to a water/glycol mixture. Glycol lowers the freezing point and protects the loop, at the cost of slightly reduced heat-transfer efficiency, so the concentration is tuned to the target temperature.
Capacity and temperature range
Industrial chillers span a very wide performance range. Two figures define most selections: cooling capacity — how much heat the unit can remove, measured in watts or kilowatts — and temperature range and stability, meaning the set point it holds and how tightly it holds it.
Eldrotec’s chiller lineup illustrates the spread. Compact units start at around 1 kW and scale up to 30 kW process chillers. Standard models typically operate in the 5°C to 40°C range, high-precision models hold stability as tight as ±0.1°C, and extended-range models reach from -20°C up to 90°C. Both air-cooled and water-cooled configurations are available, and for requirements that fall outside the standard envelopes, custom power, temperature, and dimensional specifications can be engineered to order. The full range and series breakdown is available on the recirculating chillers page.
Common applications
Anywhere a machine generates heat that must be removed precisely, a chiller is likely involved. Typical applications include:
- Laser and RF systems — stable cooling protects optics and maintains beam quality and power output.
- Medical imaging — MRI, CT, and ultrasound equipment rely on chillers to stay within spec. See medical industry solutions.
- Semiconductors and electronics — wafer processing, test, and burn-in demand tight thermal control. See semiconductors & electronics.
- Manufacturing — injection molding, plating, and CNC machining use chillers to hold process temperature and improve cycle times.
- Defense and aerospace — ruggedized cooling for demanding environments, including MIL-STD systems.
- Laboratory and R&D — compact benchtop chillers cool instruments and experiments with repeatable accuracy.
How to choose the right chiller
Selecting a chiller comes down to matching the unit to the heat load and the fluid conditions of the process. The essentials to define are the cooling load (the amount of heat the process generates), the set-point temperature and the precision required, the flow rate and pressure the equipment needs at the coolant connection, the coolant type (water or a water/glycol mix), and the heat-rejection method (air-cooled or water-cooled).
Getting the cooling load right is the single most important step. If you are unsure, the Eldrotec engineering team can size a system for your application — and because every model can be customized, the final unit can be matched exactly to your power, temperature, and integration requirements.
Frequently Asked Questions
What is an industrial chiller used for?
An industrial chiller removes unwanted heat from a process or piece of equipment and holds it at a stable temperature. It circulates chilled liquid — water or a water/glycol mix — through machinery, heat exchangers, or cold plates, then carries the absorbed heat back to be rejected. Typical uses include laser systems, MRI and medical imaging, semiconductor testing and fabrication, injection molding, and laboratory equipment.
How does a chiller work in simple terms?
A chiller cools liquid using a refrigeration cycle. A compressor pressurizes refrigerant, which releases heat in the condenser, expands and cools through an expansion valve, then absorbs heat from the process fluid in the evaporator. The chilled fluid is pumped to the equipment, picks up heat, and returns to repeat the loop continuously.
What is the difference between air-cooled and water-cooled chillers?
The difference is how the chiller rejects the heat it collects. An air-cooled chiller blows ambient air across the condenser, while a water-cooled chiller uses a separate water circuit, often paired with a cooling tower. Air-cooled units are simpler to install; water-cooled units suit higher capacities and hot environments. Eldrotec’s PWN and PWNH Series are available in both air-cooled (A suffix) and water-cooled (W suffix) configurations.
What is the difference between a chiller and a cooling tower?
A chiller actively refrigerates fluid and can hold it well below ambient temperature with tight precision. A cooling tower only rejects heat through evaporation and cannot cool below the ambient wet-bulb temperature. In many water-cooled systems the two work together: the tower rejects heat from the chiller’s condenser, while the chiller delivers the precise process temperature.
What temperature can an industrial chiller reach?
It depends on the series. Eldrotec standard chillers operate from about 5°C to 40°C, high-precision models hold to ±0.1°C, and extended-range models reach from -20°C up to 90°C. Custom liquid temperature ranges are available to meet specific process requirements.
Do industrial chillers use glycol?
Yes. When a process must run below the freezing point of water or needs freeze protection, the chiller circulates a water/glycol mixture instead of plain water. Glycol lowers the fluid’s freezing point and protects the loop, though it slightly reduces heat-transfer efficiency, so the concentration is matched to the required temperature.