Performance evaluation of ground-source heat pump system and development of suitability map for its installation

Abstract:

Ground-source heat pump (GSHP) system is an energy efficient and environment friendly technology that uses natural subsurface heat energy stored in the shallow depth for space-heating, space-cooling, snow-melting, hot water supply etc. In Japan, development of this system is gradually increasing, however the rate is still limited due to higher initial cost caused by oversized design of ground heat exchangers. An efficient system that can lower the installation cost should be developed and evaluated for its performance in order to expand the growth of GSHP system in Japan. In addition, development of suitability map to assess appropriate locations for the system installation is essential for optimum design and sustainability. In this study, GSHP system was constructed utilizing an artesian well as ground heat exchanger (GHE) and evaluated its performance. The objective of this study is to develop low cost and high efficiency system. In areas with abundant groundwater and its flow, higher heat exchange rate can be expected leading to cost reduction and energy saving. Further, suitability map was prepared in regional scale to assess the suitable locations where this type of system can be installed. The suitability map was prepared considering local hydrogeological and thermal data. Average coefficient of performance (COP) was found to be 7 during space-cooling operation and 5 during space-heating operation. These values of COP are higher than that of normal air conditioner (air-source heat pump system).