Energetic and exergetic assessment of a ground source heat pump system using low temperature resources in a tropical climate

Abstract

The energy crisis is a global issue which all nations are involved with it. To this purpose, scientists are developing new energy sources that have less downsides than traditional energy sources. In the current investigation, a ground source cooling system is built in a 234 m2 office building at the gas company bureau in Qom province, Iran, which has a tropical environment. In this climate, which the ground temperature is almost 21 ◦C, some closed vertical type ground coil with about 170 m depth is constructed for the system, and then some measurements are recorded. The system has been evaluated using the extracted data and energy and exergy evaluations have been conducted. The outputs show a great sensitivity of the coefficient of performance to the outlet ground coil temperature and the exergy analysis demonstrates that the exergy loss of the ground coil is slightly increased over the workday and the heat pump with exergy dissipation and exergy loss coefficient of 6.4 kW and 0.22 has higher rate of irreversibility compared to other components. Moreover, the average values of Coefficient of Performance (COP) and outlet temperature of ground coil during a workday were obtained as 4.43, 27.43C respectively.