Basic Piping for Glycol Chilling

There are a variety of materials that can installed for you glycol piping system. GF Coolfit, Pre-Insulated PVC80, welded stainless steel, copper tubing etc.

With the above, PVC80 and Coolfit tend to be the most prevalent. It really comes down to budget. Pre-insulated PVC80 is a good economical choice. As with all materials proper installation is key for durability, function and aesthetics.  A closed cell insulation similar to Armaflex is recommended on all exposed areas, including hose drops and tank piping.

It’s ideal for glycol piping systems to be installed in a reverse-return (first-in, last-out) to balance flow across all tanks or pieces of equipment being serviced with glycol (or whatever cooling medium applies).

In the case of a reverse-return (vs. direct return) the cooling medium travels the same distance to and from the chiller no matter where it is on the supply feed. There are many ways to orient equipment in a space and this will dictate the design of the reverse-return and the degree it can be utilized or installed.

For atmospheric glycol systems the equipment is filled from the bottom up (I.e. tank jackets). It is always best to install glycol flow control valves on the supply side of all equipment, so when a valve is in the closed position it isn’t leaving the equipment pressurized.

Glycol flow control and pressure can be regulated in the system with variable frequency drives on pumps, external bypass loops and with internal spring-loaded relief valves. Spring-loaded bypass valves are installed in all G&D Chillers even as a redundant back up for VFD controlled pumps.

Pipe sizing depends on the required total flow all pieces of equipment require or how many pieces of equipment will require glycol at any given moment. Pressure drop throughout the system as well as velocity through the piping system needs to be taken into account.

It is highly recommended to install isolation valves at all equipment locations off the primary, secondary line sets- depending on how the system is set up. This can be as simple as a tee with a reducing bushing out of the branch of the tee with an isolation valve installed just downstream of the bushing. Like-wise it is beneficial to isolate secondary lines from primary lines and secondary from tertiary…

With all piping systems it is a good idea to keep serviceability in mind. If your glycol mains are installed up high (above vessels/equipment) it would be ideal to install flow control valves in-line on the tank piping, if the main line sets are out of reach. The more serviceable the piping components the better.

To learn more about basic piping or other glycol chiller questions visit our Frequently Asked Questions page or contact us anytime.