Water-cooled chillers are a top choice when it comes to large-scale cooling systems, especially in commercial buildings, factories, and industrial facilities.

These systems play a crucial role in air conditioning and process cooling by efficiently transferring heat away from spaces or equipment that needs to stay at a lower temperature.

If you want to understand how a water-cooled chiller system works, you’re in the right place!

In this guide, we’ll break down the working principle of water-cooled chillers in an easy-to-understand way. By the end, you’ll have a clear picture of how these machines operate and why they are preferred over air-cooled chillers in many applications.

Understanding the Basics of Water-Cooled Chillers

Before looking into the working process, let’s first get a grasp of what a chiller is. A chiller is a cooling system that removes heat from a liquid, typically water, and transfers it elsewhere.

This chilled water is then circulated through air handling units (AHUs) or process cooling equipment to maintain the desired temperature.

There are two main types of chillers:

Air-cooled chillers – These use air to remove heat from the refrigerant.
Water-cooled chillers – These use water to absorb and transfer heat efficiently.

While air-cooled chillers are easier to install and maintain, water-cooled chillers are more energy-efficient and suitable for larger cooling loads.

That’s why they are commonly used in large commercial buildings, industrial processes, and high-capacity HVAC systems.

Key Components of a Water-Cooled Chiller

A water-cooled chiller system consists of several essential components that work together to remove heat and produce chilled water. These components include:

Compressor – The heart of the system that circulates refrigerant.
Condenser – Transfers heat from the refrigerant to cooling water.
Expansion Valve – Reduces pressure and controls refrigerant flow.
Evaporator – Absorbs heat from water, cooling it down.

Each of these components plays a crucial role in ensuring the chiller functions efficiently.

Now, let’s break down the working process step by step.

How Does a Water-Cooled Chiller Work?

Step 1: Compression – Getting the Refrigerant Moving

The process begins at the compressor, which is responsible for circulating the refrigerant throughout the chiller.

It compresses the refrigerant gas, raising its pressure and temperature before sending it to the condenser.

Different types of compressors can be used in chillers, including:

Centrifugal Compressors – Ideal for large-scale cooling.
Screw Compressors – Commonly used for mid-sized applications.
Scroll and Reciprocating Compressors – Suitable for smaller systems.

Step 2: Heat Rejection in the Condenser

Once the refrigerant leaves the compressor, it enters the condenser, where its temperature needs to be reduced.

This is where water cooling comes into play.

Cooling water from a cooling tower enters the condenser at approximately 32°C.
This water circulates through copper tubes while the refrigerant flows around them.
Since the refrigerant is at a higher temperature, heat naturally moves from the refrigerant to the water, increasing the water’s temperature.

By the time the cooling water exits the condenser, it has absorbed the refrigerant’s heat and leaves at around 40°C.

Meanwhile, the refrigerant has cooled down and changed from a high-pressure gas to a high-pressure liquid.

Step 3: Expansion – Cooling Down the Refrigerant

Next, the refrigerant moves to the expansion valve. Here, the pressure of the refrigerant is rapidly reduced, causing its temperature to drop significantly.

The expansion valve plays two key roles:

It reduces the pressure and temperature of the refrigerant.
It controls the amount of refrigerant entering the evaporator based on cooling demand.

Step 4: Absorbing Heat in the Evaporator

Now, the refrigerant enters the evaporator, which is where the actual cooling happens. The evaporator is similar in design to the condenser, but instead of cooling the refrigerant, it cools water.

Chilled water from the AHU (Air Handling Unit) enters the evaporator at around 12°C.
As this water flows through coils inside the evaporator, it comes into contact with the low-temperature refrigerant.
Heat naturally moves from the warmer water to the colder refrigerant.

As the water loses heat, its temperature drops to around 6°C before being sent back to the AHU to cool the building.

Meanwhile, the refrigerant absorbs this heat, causing it to evaporate back into a gas.

Step 5: The Cycle Repeats

The now-heated refrigerant gas returns to the compressor, where the process starts all over again.

This continuous cycle ensures that the water remains chilled and provides effective cooling for the building or process.

Why Choose a Water-Cooled Chiller Over an Air-Cooled Chiller?

While both air-cooled and water-cooled chillers serve the same purpose, water-cooled chillers have some significant advantages:

Higher Efficiency – Water conducts heat more efficiently than air, making these chillers more effective for large cooling needs.

Longer Lifespan – With proper maintenance, water-cooled chillers last longer than air-cooled systems

Lower Noise Levels – Since they rely on water for cooling, they operate more quietly compared to air-cooled chillers, which use fans.

Better Performance in Hot Climates – Air-cooled chillers struggle in high-temperature environments, while water-cooled systems maintain efficiency.

However, water-cooled chillers do require additional components like cooling towers and water treatment systems, making their installation and maintenance more complex.

Applications for Water-Cooled Chiller System

Water chillers are widely used in several sectors such as:

Automotive Electronics
Food & Beverage
Pharmaceuticals

Their capacity to deliver continuous and effective cooling renders them indispensable in these industries.

Conclusion

Water-cooled chillers are an essential part of many industrial and commercial cooling systems. By using water to remove heat, these systems provide efficient, reliable cooling for large-scale operations.

Understanding the working principle of a water-cooled chiller helps in making informed decisions when selecting the right cooling solution. Whether you are an engineer, business owner, or facility manager, knowing how these machines operate allows you to optimize performance and ensure energy efficiency.

If you’re considering investing in a cooling system for your facility, you may as well look into the manufacturers of the best-water-cooled chiller in Bangladesh – which might be the best solution for long-term efficiency and sustainability.

Frequently Asked Questions (FAQs)

What type of water is used in a water-cooled chiller system?

Typically, treated water is used to prevent scaling, corrosion, and biological growth inside the system. Water treatment chemicals or filtration systems help maintain clean water circulation and improve efficiency.

Can water-cooled chillers operate in extremely cold climates?

Yes, but precautions must be taken to prevent freezing. In cold climates, glycol mixtures (antifreeze solutions) are often added to the cooling water to prevent ice formation in pipes and coils.

Can a water-cooled chiller be used in residential buildings?

While possible, water-cooled chillers are not common in residential settings due to their size, cost, and need for a cooling tower. They are primarily used in large commercial buildings, hospitals, and industrial applications where high cooling capacity is required.

What is the lifespan of a water-cooled chiller?

With proper maintenance, a water-cooled chiller can last 20-30 years, which is longer than an air-cooled chiller (which typically lasts around 15-20 years). The key to longevity is preventative maintenance, water treatment, and regular system inspections.

Does a water-cooled chiller consume a lot of energy?

Water-cooled chillers are more energy-efficient than air-cooled chillers when running at full capacity. However, they require additional components like pumps and cooling towers, which also consume energy. The overall energy consumption depends on the chiller size, load conditions, and maintenance.

How Does A Water-Cooled Chiller System Works?