What does glycol do in a cooling system? If you are a facility manager, building owner, or property management professional seeking to improve temperature control in commercial buildings, prevent freezing in critical HVAC infrastructure, or optimize energy efficiency in your cooling operations, you have likely encountered glycol as a potential solution. Glycol can help with these goals and many more, but it is important to understand what glycol does and how it works so that you can be sure that it is the right fit for your facility.
What Is Glycol?
Glycol is a type of organic compound that belongs to the alcohol family. It primarily exists in two forms: ethylene glycol and propylene glycol, each with distinct properties that determine their applications in commercial buildings.
Ethylene glycol provides superior heat transfer efficiency and freeze protection at a lower cost, making it the preferred choice for closed-loop systems in commercial buildings where human contact is limited. However, it is highly toxic if ingested and requires careful handling and proper disposal according to environmental regulations. With a lower viscosity than propylene glycol, ethylene glycol systems typically require less pumping energy and deliver better heat transfer rates.
Propylene glycol, while approximately 10-15% less thermally efficient, is non-toxic and classified as “generally recognized as safe” (GRAS) by the FDA. This makes it mandatory for systems where there is any risk of contact with potable water, food processing equipment, or areas with high human occupancy. Although more expensive initially, propylene glycol is often required by building codes for certain applications despite its higher viscosity and pumping requirements.
Over time, both types of glycol can degrade through oxidation, especially when exposed to high temperatures. This degradation process produces organic acids that can lower the pH of the solution and potentially cause corrosion in system components. Ethylene glycol can break down into glycolic acid, oxalic acid, and formic acid, while propylene glycol typically degrades into lactic acid and pyruvic acid. Regular testing and maintenance are essential, as degraded glycol cannot be transformed back to its original state and must be replaced to maintain system efficiency and prevent equipment damage.
What Does Glycol Do In HVAC Systems?
HVAC cooling systems benefit significantly from glycol because of how it interacts with water. Water freezes at 32 degrees Fahrenheit; however, by mixing glycol with water, its freezing point can be reduced dramatically – potentially as low as -60 degrees Fahrenheit depending on the concentration. This property prevents pipes from freezing in cold weather and allows equipment to operate at lower temperatures than would be possible using water alone.
Glycol in HVAC systems also provides corrosion protection for the metal components of the system, extends equipment life, and helps maintain consistent cooling performance throughout seasonal temperature changes. These benefits make glycol an essential component in many commercial and industrial cooling applications.
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How Glycol Works In A Closed Loop System
The operation of a glycol cooling system begins with establishing a glycol water chiller in a closed loop configuration. A glycol water chiller is essentially a specialized refrigeration system designed to cool a reservoir of glycol solution to a predetermined temperature. Once cooled, the glycol solution is circulated through a sealed circuit of tubing or piping connected to the central chiller unit.
This circulation system continuously pumps the chilled glycol throughout the network, maintaining the desired low temperature throughout the entire loop. The closed nature of this system is critical for efficiency, as it prevents contamination and evaporation that would otherwise compromise performance. Proper monitoring of closed-loop systems is essential for optimal glycol performance and energy efficiency in commercial buildings.
What Does Glycol Do To Water?
What does glycol do to water in cooling systems? By mixing with water, glycol creates a solution with remarkable thermal properties. First, it lowers the freezing point substantially, allowing the mixture to remain liquid at temperatures far below water’s normal freezing point. This is essential in preventing system damage from frozen and expanding water.
Second, glycol-water mixtures maintain excellent heat transfer properties. The solution efficiently absorbs heat from vessels or spaces being cooled and transports it back to the chiller. This process is more stable and reliable than using water alone, especially in environments with varying temperature requirements.
Additionally, glycol inhibits corrosion and scale formation within the system, extending the life of pipes, valves, and heat exchangers. The typical concentration in most systems is 25-30% glycol to water (approximately one part glycol to three parts water), though this ratio may vary based on specific cooling requirements.
Heat Exchange Process In Glycol Systems
To utilize the cooling capacity of circulating glycol, heat exchangers are integrated into the system. As chilled glycol passes through these heat exchangers, it absorbs heat from vessels or spaces being cooled and returns to the chiller to be re-cooled before continuing through the loop again.
Different heat exchanger designs may be employed based on specific application requirements. Common configurations include jacketed vessels for brewery tanks, stainless steel plate exchangers for food processing, stainless steel cooling coils for immersion cooling, and air handlers for space cooling.
Contact The Glycol Cooling System Experts At Tower Water
The experienced technicians at Tower Water set the standard in water treatment and provide comprehensive support for glycol systems. Our team can perform detailed inspections of your current system and develop personalized recommendations for optimizing what glycol does in your cooling system.
For more information about how Tower Water can help optimize your glycol cooling system, reach out to schedule a consultation with our specialists. Call us at (212) 518-6475 or visit our website to arrange an appointment with our expert team.