Monitoring the Performance of a Residential Central Air Conditioner under Reduced Evaporator Air Flow on a Test Bench

Abstract

This report presents results from degraded performance measurements of a residential air conditioning system operating under reduced evaporator air flow. Experiments were conducted using a R-22 three-ton split-type cooling system with a short-tube orifice expansion device. Results are presented here for a series of tests in which the air flow across evaporator was reduced by 25%, 50%, 75%, and 90% of normal amount of air flow as specified by ARI. Return air temperature was maintained at 80 F dry bulb for all the standard and degraded experiments. Experiments were conducted for three different return humidity conditions of20% RH, 45% RH, and 65% RH and three outdoor conditions of70°F, 85°F, and 100°F dry bulb temperature. At present, very little information has been published which quantifies the degraded performance of a residential cooling system operating under reduced evaporator air flow. Degraded performance measurements can provide information which could help electric utilities evaluate the potential impact of system-wide maintenance programs.