Glycol

Glycol or propylene glycol is used in cooling or chiller systems. It is used in a mixture of distilled water and propylene glycol. The mixture depends on what your cooling needs are for the end user. The final mixture should be mixed so the rating on the glycol is at least 10-15 degrees lower than your desired temperature setting on your thermostat. The reason for this is so the glycol in the bath does not freeze since the refrigerant in the system is colder than the glycol bath itself.

There are many less expensive alternatives in the marketplace, such as RV antifreeze, or car antifreeze, but these are not designed for a re-circulating system and can break down fairly quickly and cause a buildup of sludge in your system or gum up your heat exchanger, causing your system to fail. You may also want to use a professional to work on your glycol that has the right tools and equipment to check and maintain the proper mixture in the chiller bath so it will work properly.

When purchasing glycol you want to make sure that you use a glycol that is marked USP (United States Pharmacopeia) which is the official standard setting authority for medicines, supplements, and health care products in the US. If the glycol is carrying the USP grade it provides assurance that the product is approved for food applications and is of the highest quality. Depending on the age of your equipment (check with your service company) it may require the use of the older glycol which is not food grade. If the glycol has a thicker consistency and an oily feel to it, that helps to lubricate the chiller system, so always check with your service company before changing brands of glycol to make sure it will work with your cooling system and does not void any warranties that you or your customer might have on the equipment.

Glycol comes in a wide range of colors; blue, orange, yellow, pink, and even clear. We recommend using a colored glycol to make it easier to determine if you have any leaks, so you can identify them quickly and repair the problem. The purpose of the glycol, or heat transfer fluid, is to remove the heat from one medium to another. The glycol is placed into a chiller ranging from 1/5 to 400 horsepower depending on the end customers specific needs. Every chiller has a reservoir that utilizes coils or a heat exchanger to chill down the glycol before it is circulated through the particular system. In a coil system you have soft copper lines wrapped around the inside of the glycol bath. A refrigerant is circulated through the compressor to chill down the glycol before it is pumped through the coolant lines to chill down the system. The other type of system uses a heat exchanger that is a piece of equipment built for the efficient heat transfer from one medium to another. Think of it as your car's radiator which has antifreeze in the coils (heating system) and air flows over the coils, cooling the antifreeze which is circulating through your engine and is removing the heat and then the radiator cools the antifreeze and the cycle starts over again.

The glycol chillers with heat exchangers are typically more energy efficient since they are not trying to keep the glycol in the bath cold all of the time so they use less electricity. It is important to do a regular maintenance schedule on all of your customer's refrigeration equipment so the equipment is operating at the highest levels and also, so you can find a problem before it shuts down the entire system and is costly to repair. You should have a service company come in and check out your system at least once a quarter to keep the coils cleaned and blown out, depending on the location of the chiller unit, it might be beneficial to have it done on a monthly basis if it is in a hot, dirty location, so the life of your equipment will be as long as possible. The service company will check the levels of glycol and strengths of the solution to make sure it is operating at the highest level. In the long run it will benefit you to spend a little every month or so to do the upkeep on the equipment, than replacing it when it breaks down, because it will never break at a convenient time for you or your customer.