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Propylene Glycol

What is propylene glycol?

Propylene glycol is a synthetic (man-made) liquid substance belonging to the same chemical group as alcohol. It’s odorless, colorless, nearly tasteless, and has a slightly syrupy consistency. Propylene glycol has excellent heat transfer properties and reduces the freezing point of water. 

What things are made with propylene glycol?

It has industrial, cosmetic, medicinal, even food additive applications. Some examples include:

  • Industrial: anti-freeze, paint, and artificial smoke
  • Cosmetic: moisturizers, hair products, and make-up
  • Medicine: injectable medications and in some creams and ointments that are applied to the skin
  • Food Additives: drink mixes, dressings, cake mix, soft drinks, and popcorn

How is propylene glycol used in geothermal heating and cooling?

Closed loop geothermal systems typically circulate a mixture of water and a small amount of antifreeze to lower the solution’s freezing point. Dandelion’s mixture is 22% food-grade propylene glycol.

Is propylene glycol safe?

According to the US Food and Drug Administration, it’s “generally recognized as safe”. It has very low toxicity and is widely used in medicinal products and processed foods.