OT-88-04-3 -- Power Cost Comparisons: Evaporative vs. Refrigerative Cooling PDF

Evaporative cooling and refrigerative air conditioning generate cold air for comfort cooling in very different ways. Accordingly, most past attempts to compare their relative power costs have been little more than hearsay.

This paper suggests a simple arithmetic method for such comparisons, based less on the two differing modes for cooling air than on their comparable abilities to cool rooms. Some new terms are necessarily introduced, and wide usage depends upon evaporative cooling manufacturers developing EER data for their products: specifically, EER per degree of coincident design wet-bulb depression.

With that data, this system’s accuracy seems assured. No alternative quick method seems known. For simplicity, only direct evaporative cooling is covered. Sample calculations are provided.

Units: Dual