Closed-Loop Certification


Manufacturers of products certified by the Air-conditioning and Refrigeration Institute (ARI ) Standard 330 for ground source closed-loop heat pump equipment, publish a capacity rating for each model cataloged at the standard entering water rating conditions of both 77°F for cooling and 32°F for heating. The cooling EER, heating COP and fluid flow for both is also published.

In calculating the cooling Standard Energy Efficiency Rating (EER) and the heating Coefficient of Performance (COP), a penalty for the water pump effect of 0.8 watts per gallon per minute per foot of head is added to the measured power input. This approximates a 25% total pump efficiency. Further more, a 17 foot pressure drop shall be added for the loop to determine the total pressure drop of the system for the pumping penalty.

You should not confuse the ARI Standard Energy Efficiency Rating with the expression SEER. The latter stands for Seasonal Energy Efficiency Ratio. SEER is a measure of seasonal cooling efficiency under a range of weather conditions, assumed to be typical for a location, and of performance losses due to cycling under part load conditions.

Ground-coupled units for use in Canada should be also rated in accordance with the Canadian Standards Association (CSA) and the Canadian Earth Energy Association (CEEA).