Comparison of long-term performance and initial cost of a horizontal ground source heat pump with an air source heat pump in hot regions

Ground source heat pumps (GSHPs) have received much attention due to their high coefficient of performance (COP). In these systems, the ground is used as a sink/source for heat pumps and the heat transfers between the ground and the heat pump is performed by the ground heat exchanger (GHE). In this study, the long-term performance and initial cost of these systems have been compared with conventional air-source systems in a hot region. To evaluate the performance of the GSHP, using fluent software, numerical modeling of a linear horizontal GHE was carried out in Bandar-Abbas. Also, the effect of various system operating parameters, i.e., length, distance, buried depth, and diameter of GHE pipes have been studied. According to results, the five-year COP and exergy efficiency of GSHP systems is 19.9% to 24.30% and 5.95% to 6.55%, respectively, more than that of the air-source system. However, 1.2 to 2.5 million Tomans is needed as the installation cost for each kW of maximum building load per year. Also, it is demonstrated that by reducing the length of the GHE, the initial cost is reduced, and the performance increases, the pipe spacing is the most important factor in the required ground surface, the depth has the most impact on the initial cost and the performance, and the pipe diameter does not affect the system performance.