Development of a design and performance prediction tool for the ground source heat pump system

This paper introduces a novel design and performance prediction tool for the ground source heat pump (GSHP) system. This tool features, a user-friendly interface for data input and graphical output. First, an outline of this tool was described. Next, the authors validated temperature variation calculated by theoretical method of the developed tool compared with one measured in the thermal response test. The thermal response test was carried out in a house garden in Sapporo. Giving the calculated conditions, the calculated temperature variation almost traced the measured value. The developed tool’s preciseness was proved with the results. In final, performance prediction and feasibility study of a residential GSHP system in Sapporo was performed with this tool as an example. Results of the calculations show that the life cycle CO2 emission (LCCO2) of the GSHP system is 2038 kg-CO2/year and it is less than half compared to conventional oil boiler systems. Also, the GSHP system can reduce life cycle cost (LCC) by 50,000–90,000 Japanese-yen/year. The payback time for increased investment cost of the GSHP system is about 9–14 years in comparison with other conventional systems.