24 June 2014

Measured water heating performance of a vertical-bore water-to-water ground source heat pump (WW-GSHP) for domestic water heating over twelve months under simulated occupancy loads

This paper presents monthly performance metrics of a 5.275 kW (1.5 ton) WW-GSHP providing 227 L·day-1 domestic hot water at 49°C. Daily water use is simulated as stipulated in the Building America Research Benchmark Definition capturing the living habits of the average U.S household. The 94.5m vertical-bore ground loop is shared with a separate GSHP for space conditioning the 251m2 residential home. Data on entering water temperatures, energy extracted from the ground loop, delivered energy, compressor electricity use, COP, WW-GSHP run times, and the impact of fan and pump energy consumption on efficiency are presented for each month. Factors influencing performance metrics are highlighted.