Heat Transfer Fluid Resources & Calculators
Calculators & Engineering Data
Heat Transfer Fluid FAQ
Q: What is Propylene Glycol?
A: Propylene Glycol (PG) in chemical terms is known as 1, 2-propanediol and is a relatively non-toxic liquid that is colorless, odorless, and tasteless. This is the chemical that prevents water based antifreezes from freezing. Because of its low level of toxicity, it is used in many cooling and heating applications where there may be incidental contact with humans, animals, foods, and beverages. Propylene Glycol is also used in many cosmetic and food products.
Q: Why use an inhibited glycol?
A: Propylene glycol in its pure form is aggressively corrosive to the types of materials (metals, etc.) found in a common heat transfer system. It is for this reason that these glycols must be blended with a high quality anti-corrosion (inhibitor) package of chemicals to create a glycol heat transfer fluid (HTF).
Q: Does the glycol protect the metal in my systems?
A: The glycol in a system does not protect any metal from corrosion. It is only the corrosion inhibitors that are added to the glycol that protect the metal. Glycol will not affect plastic but will affect aluminum (above about 150°F) and galvanized steel. The zinc in the galvanizing will react with most inhibitors and cause loss of the zinc coating leading to localized corrosion.
Q: What is the range for glycol heat transfer fluid (HTF) dilution?
A: CORECHEM Inc. recommends a dilution range of 25% to 65% glycol with the balance being purified water. A concentration of less than 25% glycol will not only increase the freeze point (a warmer freeze point), but will also further dilute the inhibitor package which protects the heat transfer system from corrosion. We highly recommend a minimum concentration of 25% due to possible future water dilution of the heat transfer fluid in the system by untrained maintenance personnel. On the other side, a concentration of greater than 65% reduces the heat transfer efficiency of the mixture.