Ethylene vs. Propylene Glycol
Early in your fluid selection process, you should consider what local requirements might impact your choice. Local regulations or a specific application may require that you decide between the use of an ethylene or a propylene glycol-based fluid.
In most heat transfer applications ethylene glycol-based fluids are your best choice because of their superior heat transfer efficiency. This efficiency is largely due to the lower viscosity of ethylene glycol solutions. Another benefit of this viscosity advantage is lower power consumption for re-circulation pumps and a lower minimum operating temperature. DOWTHERM™ SR-1, DOWTHERM 4000, or DOWCAL™ 10 fluids are EG based fluids.
Propylene glycols are most commonly used in applications in which low acute oral toxicity is required, or for freeze protection where incidental contact with drinking water is possible. In some areas, use of propylene glycols is required by local regulation. Propylene glycol-based fluids are used extensively in food processing applications, but ethylene glycol-based fluids can also be used in some instances. The ingredients in DOWFROST™ and DOWCAL N inhibited propylene glycol-based fluids are generally recognized as safe by the U.S. FDA1. Since these products also have the appropriate approvals, they can be used in immersion freezing of wrapped foods and other food applications where ethylene glycol is not permitted. See Food Product Chilling/Freezing. Generally Recognized As Safe (GRAS) by the US Food and Administration, propylene glycol based DOWFROST can be used in immersion of freezing wrapped foods and other applications where ethylene glycol is not permitted. DOWFROST HD, DOWFROST, DOWCAL 20 fluids are PG based fluids.
1 You may need to comply with similar or additional legislation in other countries.