Antifreeze Testing

Antifreeze solutions are commonly used in geothermal heat pump systems since loop temperatures can approach or even dip below freezing while providing heating during the winter months. The most commonly used antifreeze solutions in closed loop geothermal heat pump systems are propylene glycol and ethanol. Both environmentally friendly antifreeze solutions are approved for use in these systems by the New Jersey Department of Environmental Protection. Like the antifreeze in your car, if antifreeze is installed in a geothermal loop system it needs to be monitored, tested and adjusted at regular intervals.

However, these two different fluids require different testing methods in order to determine if the required level of freeze protection is being provided. Propylene glycol is tested using an instrument called a refractometer, while ethanol can be tested with a hydrometer. Antifreeze levels can be evaluated at the same time water quality testing is completed and should be incorporated into a comprehensive maintenance plan.