Why is Glycol Used in Chillers?

Introduction

Glycol chillers are widely used in industries like brewing, food processing, pharmaceuticals and HVAC. They use a mixture of glycol and water (rather than just water) to cool equipment, prevent freezing and maintain steady temperatures. They’re ideal for applications where precise and consistent cooling is essential.

A glycol chiller is a refrigeration system that cools a glycol-water solution, which circulates through pipes to remove heat from a process or space. Glycol helps prevent freezing, improves heat transfer and protects system components from corrosion and scaling. The presence of the glycol makes it more effective than water alone in low-temperature applications.

In this blog post, we will explore why glycol is used in chillers, including what type of glycol is used. We will also look at how a glycol chiller works, covering its key parts and benefits, as well as how these systems support industries that rely on precise temperature control.

What is Glycol?

Glycol is a chemical compound commonly used in cooling systems to prevent freezing, improve heat transfer and protect equipment from corrosion. It’s a type of antifreeze that, when mixed with water, lowers the freezing point of the solution. This makes it ideal for chillers operating in low-temperature environments where water alone would freeze and cause damage to pipes and equipment.

Why is Glycol Used in Chillers?

The main reasons glycol is used in chiller systems include:

Freeze protection: glycol prevents ice formation, ensuring the cooling system operates efficiently at exceptionally low temperatures.
Corrosion prevention: glycol contains inhibitors that protect metal pipes and chiller components from rust and scale buildup.
Extended system lifespan: by reducing corrosion and freezing risks, glycol helps chiller systems last longer with less maintenance.

Types of Glycols Used in Chillers

Not all glycol is the same. The two most common types used in glycol chiller systems are ethylene glycol and propylene glycol.

Ethylene glycol: a high-performance coolant that offers better heat transfer. However, it’s also toxic, making it unsuitable for food and beverage applications.
Propylene glycol: a non-toxic alternative used in industries like brewing, food processing and pharmaceuticals - where direct contact with products could occur.

Choosing the right type of glycol depends on what the application requires, safety regulations and cooling requirements.

Using Glycol in Chillers for Different Applications

Glycol is used chillers for industries that require precise temperature control and protection against freezing. Their ability to maintain consistent cooling makes them essential for a range of applications.

Brewery & Beverage Cooling

Using glycol in chillers is critical in the brewing and beverage industry, where maintaining precise fermentation and storage temperatures is crucial.

Fermentation control: beer and wine must be kept at specific temperatures during fermentation to ensure proper yeast activity and flavour development.
Preventing freezing: unlike water, glycol prevents freezing while maintaining the cold temperatures needed for beverage storage.
Rapid cooling in wort chillers: glycol is used in breweries to quickly cool down wort (the liquid extracted from malted grains during mashing) after the boiling stage, helping to preserve flavours.

Many breweries use multi-stage glycol cooling loops, where different tanks can be kept at various temperatures using the same chiller system.

Food Processing & Dairy Industry

Food and dairy production rely on stable cooling to prevent spoilage and maintain safety standards.

Cold storage and refrigeration: glycol chillers are used in walk-in coolers, blast freezers and refrigerated transport to keep perishable items at safe temperatures.
Dairy processing: milk and dairy products require precise cooling during pasteurisation and storage to prevent bacterial growth.
Regulatory compliance: glycol cooling helps food manufacturers meet strict temperature regulations for food safety.

In many food and beverage processing plants, glycol loops are integrated with production lines to maintain consistent cooling across different processes.

Pharmaceutical & Medical Cooling

The pharmaceutical and healthcare industries require precise cooling to maintain the effectiveness of medicines and sensitive equipment.

Drug production and storage: many vaccines, biologics and medications need to be stored at low and stable temperatures.
MRI and medical equipment cooling: MRI machines and other imaging devices produce significant heat and require glycol in chillers to regulate temperature.
Cleanroom environments: pharmaceutical production facilities use glycol in chillers to maintain climate control and prevent contamination.

Pharmaceutical-grade chillers are designed to maintain ultra-low temperatures while preventing condensation and microbial growth.

HVAC & Industrial Cooling Systems

Large-scale cooling systems in commercial and industrial settings benefit from freeze protection and corrosion resistance, and are suitable for low-temperature applications.

Building climate control: many HVAC systems use glycol in chillers to cool air in large commercial spaces like hospitals, office buildings and data centres.
Process cooling in manufacturing: industrial equipment generates heat that must be released to avoid damage, and using glycol in chillers provides steady, controlled cooling.
Data centre cooling: servers and IT infrastructure require constant cooling to prevent overheating and maintain uptime.

Glycol chillers offer a reliable, scalable solution for industries that require precise and uninterrupted cooling.

How Does a Glycol Chiller Work?

To understand how a glycol chiller works, it’s important to look at its basic function. A glycol chiller system follows the vapour compression refrigeration cycle, but instead of cooling water alone, it cools a glycol-water mixture. This chilled glycol solution is pumped through a system of pipes to remove heat from a process, equipment or space.

How Does a Glycol Chiller System Work?

Heat absorption at the evaporator
Warm glycol-water solution flows through the evaporator’s heat exchanger. The refrigerant absorbs this heat and evaporates into a gas.
Compression of the refrigerant
The low-pressure refrigerant gas enters the compressor, where it is compressed to increase its temperature and pressure. The compressor plays a key role in moving refrigerant through the system to provide continuous cooling.
Heat rejection at the condenser
The high-temperature refrigerant moves into the condenser coils, where heat is expelled into the air (or water, depending on the type of condenser). Fans or a cooling tower help release the heat from the system, allowing the refrigerant to condense back into a liquid.
Expansion and recirculation
The expansion valve reduces the refrigerant’s pressure and temperature, preparing it to absorb more heat. The refrigerant enters the evaporator again, and the cycle repeats continuously to maintain the desired cooling temperature.

How a Glycol Chiller Works Compared to Water Chillers

Here’s why glycol makes a difference:

Feature	Using Glycol	Using Water Only
Cooling medium	Uses a glycol-water mixture	Uses water only
Freeze protection	Prevents freezing in low temperatures	Risk of ice formation in cold conditions
Corrosion resistance	Protects pipes and system components	More prone to corrosion and scale buildup
Low temperature performance	More stable cooling at lower temperatures	Works best in moderate temperatures

Conclusion

Glycol has an important part to play in industries that require precise low temperature control and freeze protection. Investing in the right glycol chiller system and routine maintenance can ensure businesses provide reliable operation for years to come.