All about Glycol used for Process Chiller Systems

Back in the day, when I was in the process chiller manufacturing and contracting business, the subject of heat transfer fluid, also knows as glycol, was one of the least understood topics that we had to deal with.

This blog post covers key Q&A from a recent Master Class Podcast with Scot Kuscey of Thermal Fluids Inc.

Back story about Scot..

Back in 2002, Scot contacted me just out of the blue about providing heat transfer fluid (glycol) for wineries that I was providing a lot of process chillers for at the time.

One thing led to another, and I started using his propylene glycol products quite often.

On with the Q&A..

Host: What type of customers do you serve to require the use of glycol?

Scot Kudcey: Mostly mechanical contractors and HVAC. These folks include:

> Companies that are installing process chillers and piping systems.
> System that requires heat exchangers and pumps
> Hospitals
> Schools
> Office buildings
> Arenas
> MRI equipment

Mainly any mechanical system that uses fluid (water) as a cooling medium located in colder climates.

Host: What is one of the more interesting projects you have provided glycol for recently?

Scot Kudcey: MetLife field where the Giants play in New York we sold them, I think was six tanker trucks of glycol. Apparently, they needed it to keep the field from freezing up.

Host: What are some of the most common misunderstandings in your long career doing this so that your customers have or people that call you for your products?

Scot Kudcey: Many people don’t know glycol what it does and know to use it for some reason. A while back, I quoted someone on some glycol for their process chiller. When they saw my price, they said to me, “Why can’t I just use an automotive antifreeze like prestone?”. I needed to explain you can’t use automotive antifreeze and heat transfer systems and vice versa. I explained the main differents is the corrosion inhibitor package. Using an over-the-counter antifreeze in a process chiller or any other heat transfer system will cause serious damage for sure.

Host: What are the most common types of glycol used in heat transfer systems such as process chiller?

Scot Kudcey: Propylene and ethylene glycol. About 95% of the glycol we sell these days is propylene glycol and 5% ethylene glycol. The main difference is, for the most part, propylene glycol is non-toxic. Ethylene glycol is listed by many municipalities as a hazardous material these days.

Interesting fact, a lot of people don’t know about it. Next time you are in the shower, look at the back of your shampoo or conditioner bottle. It is very common to see propylene glycol as one of the ingredients.

Host: Can you give me a rundown on the top items that HVAC technicians and contractors could take away from this podcast experience to make it possible for them to provide better service to their clients who use a heat transfer fluid?

Scot Kudcey: First, you want to make sure that you get it from a trustworthy and reliable source when you get glycol for a system. Stick with the people who specialize in glycol uses for process chiller systems.

Next, make sure to compare product spec sheets. There can be a significant difference in price based on the quality of the inhibitor used. These same spec sheets should indicate that the glycol is new (as in never used) compared to recycled glycol.

Lastly, there is some shady stuff going on in the glycol market. Unfortunately, glycol is not regulated as much as you would think.

Host: Can you use glycol in process chiller systems piped with PVC?

Scot Kudcey: We found that the propylene glycol does not impact the PVC itself. The issue is with the glue joints. There can be some chemical reaction with the propylene glycol and the glue resulting in leaks.

Host: How often should glycol be testing in a process chiller system?

Scot Kudcey: Running into extreme changes in temperatures change, extreme changes in flow rates, and things like that, where it beats up everything, you might want to test yearly.

Host: Can you use DI water in a process chiller system.

Scot Kudcey: Yes, as long as your glycol is a quality inhibitor with no less than 20% concentration.