Why use glycol instead of water?

GLYCOL CHILLER VS. WATER CHILLER - WHY USE GLYCOL?

The global demand for industrial process cooling remains consistently high. Reliability and minimal downtime are key to ensuring efficient and profitable industrial and commercial operations.

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This article explores the optimal methods for achieving the necessary temperatures in production processes across various industries, such as metal finishing, medical, brewing, and agriculture.

How Does A Chiller Function?

So, how does a chiller work? The operation follows a loop, beginning where the cooling medium connects with your process equipment.

The coolant absorbs thermal energy from the process, generally leading to a phase change into a gas. This gaseous refrigerant is then directed to a condenser that expels the heat through evaporative condensation or a cooling tower. This heat exchange causes the coolant to revert to a cooler liquid, which is then sent back to the process heating source for the cycle to continue.

What Type of Coolants Are Used in Chillers?

The choice of coolant in a chiller is influenced by process requirements and cost considerations. The most common coolants are water or a mixture of water and a substance with suitable thermal conductivity, such as glycol compounds.

Water

Water is often used as chiller fluid due to its economical nature, as it can usually be sourced inexpensively. Additionally, purified water (deionized, reverse osmosis) can enhance cooling efficiency in water-based chillers.

Glycol

Glycol-based coolants consist of ethylene glycol or propylene glycol. Although they share similar properties, they should never be mixed. Glycol coolants offer significant advantages, including better corrosion resistance and antifreeze properties.

Why Is Glycol Used for Cooling

Using a glycol-water blend as a chiller coolant offers various benefits over plain water due to its unique properties, like a lower freezing point.

Water vs. Glycol Heat Transfer

Pure water freezes at 32°F, whereas pure ethylene glycol solidifies at 8.9°F. Altering the glycol-water mixture though changes its freezing point. For instance, a 10% ethylene glycol solution freezes at 25.9°F, while a 60% solution can withstand temperatures as low as -63°F.

This analysis demonstrates that glycol has refrigerant properties better suited for chillers operating in low-temperature conditions. Water coolants, if frozen, can obstruct circulation and reduce overall efficiency.

In contrast, glycol's antifreeze properties ensure the coolant remains in a liquid state, enhancing the chiller's effectiveness.

Glycol Chiller vs. Water Chiller

Both glycol and water chillers can effectively dissipate heat from production processes, but they differ in their freezing points and heat conduction capabilities. For more information on Glycol Water System, feel free to contact us.

Pure glycol or a glycol-water mix has a much lower freezing point than water, making glycol chillers preferable in low-temperature environments. Water excels in heat retention and transfer, resulting in higher efficiency for water chillers compared to glycol variants.

Operators should consider the ambient temperatures of their setup when choosing the appropriate chiller type.

How Does a Glycol Chiller System Work?

A glycol chiller plant includes a refrigeration component and tubing filled with a glycol-water mixture. The chilled fluid from the refrigeration unit flows through a thermal exchanger surrounding the heated process. After absorbing heat, the warmed coolant returns to the refrigeration unit for cooling, thus repeating the process.

Percentage Glycol in Chilled Water Systems

Many chiller systems utilize a 60/40 mixture of ethylene glycol and water, significantly enhancing the antifreeze properties. This is particularly beneficial for rapid cooling processes that need to reach low temperatures without freezing the coolant in the pipes.

How Does a Water Chiller System Work?

A conventional water chiller operates based on heat transfer principles between different mediums, both fluid and solid. These cooling systems function through heat absorption or vapor compression. The basic components include a refrigeration unit and a piping system that circulates the chilled coolant.

See Cold Shot Chillers' Line of Performance Chillers

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When should glycol be used in a closed-loop system? Glycol possesses antifreeze properties that protect coils in a closed-circuit cooler from freezing during winter in colder regions. In warmer areas like Florida or Arizona, glycol solutions are used primarily for corrosion inhibition.

Typically, about half of closed-circuit cooling applications use water, and half utilize glycol. Which is better for a closed-loop system? Due to its superior heat transfer capabilities, water is more frequently used in warmer climates and is generally more cost-effective, leading to smaller units with lower pumping horsepower requirements.

In most situations, companies opt for glycol only to prevent freezing and subsequent coil damage in low temperatures. If water is used in colder regions, maintaining minimum flow and temperatures above 45°F is crucial to avoid freezing risks.

Considerations against converting from water to glycol include the costs associated with glycol (especially for larger systems), diminished heat transfer rates requiring larger units, and increased pump horsepower for glycol.

All these factors must be weighed when deciding on water versus glycol for your closed-loop system. For more assistance, please reach out to your local EVAPCO sales representative.

Contact us to discuss your requirements regarding How Does a Glycol Chiller Work. Our knowledgeable sales team is ready to help you find the best options tailored to your needs.