While glycol is not as efficient of a heat transfer medium as water and also reduces pumping capabilities, it does provide freeze protection for the cooling system. Thermal Care recommends using a glycol solution whenever process water set point temperatures drop below 45°F.
You might wonder why you need freeze protection starting at such a high process water set point temperature? You must keep in mind that the refrigerant temperatures will be 10°F to 15°F below the glycol chiller’s process set point. Since most breweries and distilleries operate with process set point temperatures at 25°F to 27°F they will see refrigerant temperatures of around 10°F to 15°F. Maintaining the appropriate percentage of food grade glycol will ensure appropriate freeze protection.