A nominal 2-ton capacity ground-source heat pump was tested in cooling mode with and without fresh air to characterize its moisture removal and cooling capabilities in both cases. Tests were first performed with the heat pump only, to characterize its performance in accordance with ARI Standard 330, and later, in the cases using fresh air, tests were performed with and without an enthalpy exchange unit. Fresh air was supplied at a humid state above that of the conditioned air and in accordance with the guidelines of ASHRAE Standard 62-1999. Without fresh air, under ARI conditions, the heat pump performed in line with expectations. At the cooling standard rating condition--77ºF fluid temperature and 80/67ºF (dry bulb/wet bulb) return air state--the measured air-side capacity was 32,815 Btu/h with a condensation rate of 9.76 lb/h. Following ARI testing, fresh air at temperatures between 55ºF and 90ºF and at 90% RH was introduced at a rate of 320 cfm, with and without the enthalpy exchange system. The heat pump was tested in cooling mode with two indoor air states--ARI and 70ºF/50% RH. Rates of moisture introduction from fresh air, moisture removal from the enthalpy exchange wheel, and moisture removal by the heat pump were all monitored, as were sensible transfers of heat in both cooling and heating modes. Resulting from this study is a characterization of the moisture removal and sensible cooling abilities of the combined system working in a variety of modes under a variety of indoor and fresh air conditions. With information gained from this parametric study, coupled with knowledge of the thermal loading characteristics of the conditioned space, a designer is better able to match equipment capabilities with desired classroom conditions.

Units: Dual