The pros and cons of adding glycol to HVAC systems using chilled water coils or hot water coils

Water-based HVAC systems that are exposed to freezing temperatures may be damaged due to the formation of ice, which causes coil tubes to swell, rupture or burst. As a result, glycol is often added to water to prevent freezing in systems that use

Deciding which type of glycol to use in your HVAC system depends on several things, including local regulations. Let’s look at some of the pros and cons of using ethylene glycol or propylene glycol in systems that have chilled water coils or hot water coils. Ethylene glycol is the most common antifreeze fluid for standard heating and cooling applications because of its outstanding heat transfer efficiency. Ethylene glycol has a high boiling point, low freezing point, and is stable over a wide range of temperatures. It also has a low viscosity, so less power is required for recirculating pumps. However, because of its toxicity, ethylene glycol should be avoided if there is the slightest chance it could leak into water or food processing systems.Propylene glycol is used extensively in food processing applications, where low toxicity is necessary. It is also used for freeze protection where contact with drinking water is possible, and it can be used in enclosed spaces. In some areas, regulations may require the use of propylene glycols instead of ethylene glycols.

For either type of glycol, as the concentration of glycol in the solution increases, the performance of the heat transfer fluid decreases. It is important to use the lowest concentration of glycol necessary to meet your freeze protection needs.

Solutions containing glycol may affect the various types of metals and plastics commonly used in HVAC systems, and corrosion is possible in some metals. Water quality also plays a factor in the performance of the solution.

If you aren’t sure how glycol impacts your system, be sure to ask when ordering your chilled water coils and hot water coils from Emergent Coils.