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Among many responsibilities, ensuring the efficient and safe operation of HVAC systems is a key obligation of building managers and owners. One of the major components serving a significant role in the maintenance of these systems is the use of glycol.
Propylene glycol is an integral chemical in HVAC applications across the northeast where winter temperatures frequently drop below freezing. By lowering the freezing point of water, glycol prevents pipes and equipment from being at risk in the cold.
This article will examine how propylene glycol enables heat transfer and protects components in closed-loop systems, cooling towers, and chillers.
Glycol proves essential for allowing water-based cooling systems to operate through freezing conditions by preventing burst pipes, equipment icing, and loss of performance in chillers, cooling towers, and chilled water distribution.
Chilled water loops circulate water year-round to provide cooling to a building's air handlers and other equipment. During winter, if piping is exposed to outside air, there is a risk of pipes freezing and bursting when outdoor temperatures drop below the water's freezing point.
Adding propylene glycol to the chilled water also lowers its freezing point below the expected winter minimum temperature, allowing the distribution pipes to keep flowing even in frigid conditions. Glycol also prevents slushing, which occurs when ice begins to form but does not completely freeze, impeding flow through the pipes, and in turn forcing your pumps to work harder.
For cooling towers that operate continuously through the winter instead of seasonally, glycol may also be used. During cold weather, glycol lowers the freezing point of the circulating water so ice does not accumulate in the fill or sump.
Preventing freezing protects the tower from frost damage, allows for proper water distribution, and maintains heat transfer efficiency by avoiding mineral scale formation that occurs when water evaporates but cannot drain from the system.
Chillers require glycol when at risk of water freezing, such as in cold climates, when producing chilled water below 45°F, or supplying air handlers with below-freezing coil temperatures.
Water-cooled condensers also need glycol to stop expansion damage from freezing. Any chiller application allowing water to drop below its freeze point should use glycol to keep the system operational and avoid equipment damage during winter.
As buildings in the northeast rely heavily on propylene glycol to avoid HVAC disruption in frigid conditions, undertaking measures to ensure correct glycol use is essential.
This includes following recommended concentrations, testing and monitoring inhibitor levels regularly, and flushing your system when necessary. When applied and maintained properly, propylene glycol is an indispensable fluid that keeps heating and cooling operations running smoothly through the coldest northeast winter.
Propylene glycol concentration should be checked regularly, such as before the start of each cooling season, to ensure the solution provides adequate freeze protection. A glycol refractometer is the most accurate way to test concentration, but glycol test strips can also be used for a quick reading.
The ideal propylene glycol concentration for HVAC applications is 30-50% by volume, which provides freeze protection down to -15°F to -60°F depending on the exact percentage.
The concentration percentage is also important because too little glycol will not prevent freezing, while too much can impede heat transfer, increase pump strain, and lead to additional efficiency issues. Keep an eye out for leaks in your system that could potentially allow fluid to escape or allow air or moisture to degrade your glycol mix.
Glycol solution contains corrosion inhibitors that prevent fluid degradation of system metals when maintained properly. In addition to testing inhibitor levels every 3-6 months, glycol's pH and presence of contaminants should also be checked.
Glycol pH should fall between 7.0-9.5, and contaminants like sediment, biofilm or oil will reduce effectiveness. If inhibitors drop below 30-50% of initial concentration, if the pH is outside the acceptable range, or if contaminants are present, the entire glycol charge should be replaced to prevent corrosion, biological growth, and loss of heat transfer capability. Using a reputable lab to analyze glycol samples can help determine if replacement is needed.
Contact us to discuss your requirements of Glycol Temperature. Our experienced sales team can help you identify the options that best suit your needs.
If glycol begins to break down toward the end of its lifecycle, a full system flush should be performed to remove old glycol, and prevent buildup of particulate contaminants within the system. Flushing circulates fresh water through the system to wash away sediment, scale, oils, and other debris that can accumulate over time.
It also removes any biofilm growths that can inhibit flow and heat transfer, or contaminate future refills. It is important to understand that when flushing, if any glycol residue remains in the system, it will continue to break down, altering the chemistry of the water in your pipes. Chemical cleanings can be performed in these situations, as opposed to just using water, to prevent glycolic acid.
Partnering with professional water treatment companies provides the testing, chemicals, and expertise required to properly maintain your HVAC glycol. Their extensive knowledge, lab relationships, routine assessments, and preventative recommendations keep your system running at peak efficiency, and help avoid expensive repairs.
Trusting glycol maintenance to experienced water treatment specialists ensures your HVAC system continues operating reliably through freezing weather. At Tower Water, our ability to combine our expansive reach with a personal touch helps set us apart, ensuring that each client feels valued.
Our seasoned professionals are adept at guiding you through every facet of cooling tower operation. We pride ourselves on being a one-stop solution for all your water treatment needs, crafting tailored solutions that directly address your unique challenges.
Contact Tower Water today, at 212.518., or toll-free at 212.518., or schedule a consultation online to explore the array of water treatment services we offer.
If your cooling system operates at below 6°C, or is based in a location where the ambient temperature can approach 0°C, Glycol provides protection against the water in the pipework of the system freezing. This will cause the unit to operate inefficiently and could cause the pipework to burst damaging your equipment and stopping your process in its tracks.
If you're completely new to the application of Glycol and need a reference for the future, you will find below a few vital points to keep in mind when selecting the right Glycol for your unit.
Automotive Antifreeze is formulated specifically for automotive engines operating at much higher temperatures. It is therefore unable to maintain the levels of heat transfer required for a chiller.
Automotive Glycol can also contain other non-glycol chemicals, including alcohol or glycerin. These differences can lead to clogging in your system's pipework, causing your unit to under perform and fail over time. Automotive Glycol might be more readily available, but you should always buy Glycol from a specialist provider.
You should consider toxicity as a major factor when purchasing Glycol, because depending on what product you produce or service you provide, the Glycol will need to meet minimum toxicity requirements. If you're working in an industry that does create products that are consumed, an ethylene-based Glycol, such as Flowcool IG will likely be suitable.
Glycol, due to its chemical composition is corrosive to metal in its uninhibited form, meaning it will cause the internal pipework in your chiller to corrode, scale and rust ' sometimes too quickly to be noticed before there's a problem. By using inhibited Glycol, (which contains inhibitors that bind to the internal pipework of your system), a thin molecular layer will be created that protects your system but doesn't effect your system's efficiency.
Because of the chemical differences and variances in formula between brands, it is important that you not only use the correct type of Glycol, but also the same brand. Failure to maintain consistency can cause the inhibitors in the formula to stop working. This will clog up your pipework because of incompatibility.
Every aspect of manufacturing is under scrutiny by environmental agencies. Chiller water systems are no different due to the danger they pose to the environment. Much like refrigerants, Glycol and its environmental impact is under constant scrutiny. Ensure that you have an environmentally responsible plan for storage and disposal of Glycol or you could face a fine.
It is important to ensure that you use the correct concentration of Glycol for your unit. Too little can lead to bacteria growth or freezing in the pipes ' which will cause damage to the internal pipework of your system. Too much Glycol can lead to the fluid in your unit becoming thicker than the internal pump can handle. This can damage your equipment and lower its lifecycle. Concentrations over a certain threshold can even cause the freezing temperature of the liquid to rise. This can reverse the benefit of using Glycol in the first place.
Many businesses use water that comes directly from the tap or ground mains. These can contain deposits ' that are invisible to the human eye ' or additives such as fluoride that can interact poorly with the Glycol and internal systems of the unit. This can shorten their lifespan and increase the cost of servicing the unit.
Because of the above issues, it's recommended that you use 'pure' water that has been distilled, demineralized, deionized or reverse osmosised. This is a process that removes the salt in the water of your system and will reduce the unpredictability associated with tap water.
The chilled water system must be flushed, cleaned and sanitised prior to adding a new water/glycol solution.
Are you interested in learning more about Glycol to Water Ratio in Chiller? Contact us today to secure an expert consultation!