Propylene Glycol: Essential for HVAC Protection

When it comes to the complex world of heating, ventilation, and air conditioning (HVAC) systems, one of the most critical components isn’t a machine but a fluid: propylene glycol. At VAPCO, we understand that protecting your HVAC equipment is paramount, especially in cold climates. That’s why we provide superior propylene glycol solutions.

Manufacturers use both ethylene and propylene glycol as heat transfer fluids. However, propylene glycol has become the industry standard for residential and commercial applications because of its significantly lower toxicity. This makes it the safer choice for systems where an accidental leak could pose a risk to people, pets, or the environment. Though it may be slightly more viscous and have a higher freezing point than ethylene glycol, its safety benefits far outweigh these minor differences.

The Science Behind Propylene Glycol

First, propylene glycol is a colorless, odorless, and viscous liquid with a slightly sweet taste (don’t taste it). Additionally, its unique chemical properties make it an ideal heat transfer fluid and protectant for a variety of systems.

Freeze Protection: For instance, when you mix propylene glycol with water, it dramatically lowers the solution’s freezing point. Therefore, this is its most critical function. For HVAC systems in colder climates—from the snowy Midwest to the chilly Northeast—a properly treated glycol solution prevents water from freezing, expanding, and causing catastrophic damage to pipes and coils. A higher concentration, for example, offers more robust protection against freezing and bursting.
Corrosion Inhibition: Water alone is highly corrosive to the metal components in HVAC and boiler systems, leading to rust, scale, and costly equipment failure. In fact, propylene glycol is less corrosive than water, but for complete protection, we add specially formulated corrosion inhibitors. These inhibitors create a protective barrier on metal surfaces, extending your system’s lifespan and ensuring optimal performance.
Bio-stability: Without a doubt, water in a closed-loop system can become a breeding ground for bacteria, algae, and fungi. These microbes form a slimy film, or biofilm, that clogs pipes and reduces heat transfer efficiency. Fortunately, propylene glycol, particularly in concentrations of 20% or higher, actively inhibits the growth of most microbes and fungi, which keeps your system clean and running smoothly.
Heat Transfer Efficiency: Finally, as a heat transfer fluid, propylene glycol excels at moving thermal energy throughout a system. Whether it’s removing heat from a building on a hot summer day or distributing warmth from a boiler in the dead of winter, its thermal conductivity contributes to the overall efficiency of the HVAC unit.

HVAC Glycol: Essential Applications in Chillers, Boilers, and More

Propylene glycol’s versatility makes it a foundation of modern climate control technology. Its applications are broad, ensuring systems remain operational and efficient across various industries.

Applications in HVAC and Boiler Systems

Closed-Loop Systems: These systems circulate water in a continuous loop and rely on propylene glycol to prevent freezing and bursting. Technicians base the concentration of glycol in these systems on the lowest expected ambient temperature.
Chillers: In large commercial and industrial buildings, chillers are essential for cooling. Propylene glycol protects the internal coils and tubing of these systems from freezing, especially during low-load operation or in cold weather.
Cooling Towers: You can add propylene glycol to cooling tower water to prevent freezing during off-season or nighttime operation. It can also help control scale formation.
Boilers: Beyond just HVAC, manufacturers use propylene glycol widely in boiler systems as a heat transfer fluid, protecting internal components from corrosion and freezing.

Key Industries That Rely on Commercial Glycol

Hospitals and Healthcare Facilities: These buildings have complex HVAC systems for climate control in patient rooms, operating theaters, and labs. The need for consistent temperature and system reliability makes them heavy users of glycol.
Schools and Universities: Large campuses with multiple buildings and central plant systems often utilize glycolfor heating and cooling. This protects their extensive infrastructure from freezing, especially in colder climates.
Data Centers: These facilities generate immense heat and rely on highly efficient chillers to maintain a stable environment for their servers. Glycol is a critical component in these cooling systems to prevent downtime.
Industrial Plants: Manufacturing and processing facilities, particularly those in the food and beverage, pharmaceutical, or chemical industries, use glycol for process cooling and to protect sensitive equipment.
Large Commercial Buildings: High-rise office buildings, shopping malls, and large commercial complexes with centralized HVAC plants are prime targets. They use glycol in their chiller and boiler systems to manage climate control across a wide area.

Other Uses of Propylene Glycol

Although VAPCO specializes in HVAC solutions, propylene glycol’s unique properties are leveraged across many other fields:

Automotive: Found in water-based and waterless engine antifreeze formulations.
Deicing: A key component in deicing fluids for aircraft and runways, ensuring safe operation during winter.
Plastics & Polymers: Both ethylene and propylene are used to produce fibers for clothing and fabrics as well as certain plastics.
Consumer Products: Used as a humectant to maintain moisture in food and tobacco, and as a primary ingredient in RV and pool winterizing solutions. It’s also commonly used as a base for creams, lotions, and ointments.

Glycol Concentration and Annual System Maintenance

Determining the correct concentration of a propylene glycol solution is paramount. It’s a careful balancing act:

Higher Concentration: Provides a lower freezing point, offering greater protection against extreme cold.
Lower Concentration: Has a lower viscosity, which can improve pump performance and overall heat transfer efficiency.

Using the wrong concentration can lead to insufficient freeze protection or a solution that is too thick, overworking pumps and reducing the system’s efficiency. For this reason, VAPCO provides a detailed glycol calculator and encourages regular testing to ensure your system’s fluid is perfectly balanced for its specific environment and application.

Consequently, you should test your system’s glycol solution annually for optimal performance. The solution’s color can be a good initial indicator—new solutions are typically clear or dyed blue for easy detection. However, a professional test is the only way to confirm concentration, pH balance, and the inhibitor levels needed to prevent corrosion and microbial growth.

VAPCO Solutions: Quality Propylene Glycol You Can Trust

At VAPCO, we don’t just supply chemicals; we provide comprehensive solutions for the HVAC industry. Therefore, we offer two distinct grades of propylene glycol to meet your specific needs:

Standard Glycol: This GRAS (Generally Recognized as Safe) formulation is suitable for most closed-loop HVAC and boiler systems. Arctic Protection – Available in: 1, 5, 55, 275 gallons and tanker loads.
NSF-Listed HT-1 Glycol: For applications in food and beverage facilities where incidental contact with food or potable water could occur, our NSF-listed HT-1 propylene glycol is the safe and certified choice. Available in: 5, 55, 275 gallons and tanker loads.
DIW: Deionized water is vital for topping off your system with clean, pure water to help prevent corrosion and maximize efficiency. Available in: 5, 55, 275 gallons
GI: Glycol inhibitor is a powerful solution designed to protect glycol systems. Available in: 1, 5, 55, 275 gallons.
HSC: Hydronic System Cleaner is a metal-safe cleaner that effectively removes contaminants in new and old systems alike. Available in: 1, 5, 55, 275 gallons.