Thermal performance of a residential desuperheater/water heater system

Abstract

A residential desuperheater/water heater system was tested in a laboratory under controlled environmental conditions. The desuperheater, integrated to a thermal storage system, was installed in the Dual-Air Loop Test Facility at The Center for Energy Studies, The University of Texas at Austin. The major components of the system consisted of the refrigerant compressor, domestic hot water (DHW) desuperheater, thermal storage tank with evaporator/condenser coil, DHW storage tank, DHW circulating pump, space conditioning water circulation pump, and indoor heat exchanger. Although measurements were made to quantify space heating, space cooling, and domestic water heating, this paper only emphasizes the desuperheater/water heater performance of the unit. The desuperheater system was tested over a range of outdoor conditions to determine parameters such as desuperheater rate and DHW temperatures. The desuperheater rate decreased with entering water temperature, since the heat transfer between the water and refrigerant decreased as the entering water temperature increased. In addition, the desuperheater coefficients of performance decreased with entering water temperature. The DHW tank first-hour rating, F, was 52.9 gal/h. The recovery efficiency and energy factor were 0.74 and 0.77, respectively.