Using glycol in your chiller may prove to be beneficial.  Glycol reduces the freezing point of process fluid and ensures that it continues to flow at the operating temperature.  Using inhibited glycol in your system will prevent scale and corrosion from forming, algae and bacteria will not grow and metals such as copper, brass, steel cast iron and aluminum are protected.   However, there are some things to know when using glycol in your chiller that if not followed properly, problems may follow.  

1. Don’t Use Automotive Grade Anti-Freeze!

Do not use automotive grade anti-freeze. Automotive glycols are not designed for industrial applications any may foul the heat exchanger and compromise heat transfer.  

2. Don’t Mix Glycols!

Do NOT mix different glycol types or brands.  Mixing of glycols can often result in clogged filters or gelling.  If switching glycol, you will need to thoroughly clean the system to remove the current fluid.  Once it is thoroughly flushed, it is perfectly fine to change the type of brand.   

3. What is the Difference Between Ethylene and Propylene Glycol?

Glycol comes in two varieties: ethylene glycol (EG) and propylene glycol (PG). Though both materials are bad for living things, ethylene glycol is most often used in industrial applications  and is more economical and propylene glycol becomes more viscous at very cold temperatures and is most often used near food.

4. How will Glycol Affect my Chiller?

Glycol is denser than water and the cooling capacity will be slightly reduced which will in turn increase the pumping power and the fluid temperature will increase. 

5. Check Local Regulations.

It’s important to follow all state and local regulations regarding the use and disposal of glycol and antifreeze solutions.  

6. Applications and Locations Determine Water/Glycol Mix Percentages

When determining the percentage of water/glycol mix the location and environment of the chiller (indoors vs. outdoors) is the determining factor.  If your chiller will be located indoors with zero (or no) chance of freezing, the percentage of glycol lessens.  If the chiller is located outside with low temperatures the percentage of glycol will be greater.  Applications that have a very low operating temperature(below 20°F) should use a glycol mixture that is similar to an outdoor system.

 The location of the chiller and environmental concerns must be taken into account when selecting the proper mixture of glycol and water for the chiller process. A process located completely indoors, with no chance of freezing, will require less glycol than a system located outdoors where low temperatures can cause the fluid to freeze and piping to burst. Applications with a very low operating temperature (below 20ᵒ F) should use a glycol mixture equivalent to an outdoor system. 

7. Fluid Maintenance and Filtration.

The secret to extending the life of your chiller and reducing costly down-time is utilizing a fluid filter and performing fluid maintenance.  Keep the process water and correct glycol mix maintained along with filtering dirt out of the system will prove to be the necessary steps to receiving years of service from your chiller.