Comparative analysis of geothermal-solar hybrid heat pump systems for residential applications in Afyonkarahisar, Türkiye

Afyonkarahisar is located in the inner regions of Türkiye and exhibits pronounced continental climate characteristics. The long and cold winters and the hot and dry summers make electricity, space heating, and domestic hot water (DHW) requirements a significant energy burden for residential buildings. Therefore, meeting these energy demands through renewable energy sources is of great importance.This study presents a performance analysis of a geothermal solar assisted hybrid energy system designed to meet the electricity, space heating, and domestic hot water demands of a residential building located in Afyonkarahisar. Three different system configurations with identical photovoltaic (PV) and solar collector layouts namely, a ground-coupled collector system, a geothermal probe system, and a groundwater-source heat pump system were compared through simulations under regional climatic conditions.The results indicate that the groundwater-source system achieved the highest performance due to the stable temperature of the groundwater and the effective integration of the PV system. This system emerged as the most efficient configuration, with an SPF of 4.38 and a VDI-SPF of 7.51, while also achieving the lowest annual electricity consumption (944 kWh) and the highest self-sufficiency ratio (67.7%). The geothermal probe system ranked second with an SPF value of 3.83, whereas the ground-coupled collector system provided a balanced alternative in terms of performance and cost. Overall, it was concluded that the groundwater-source system represents the most efficient and sustainable solution for electricity generation, space heating, and domestic hot water production in residential buildings located in Türkiye’s regions with high geothermal potential.