Energy optimization of photovoltaic-thermal-coupled ground-source heat pumps across Iraqi climates

This research investigates the performance and cost-efficiency of hybrid ground source heat pump systems integrated with photovoltaic-thermal collectors across Baghdad, Mosul, and Basra. Simulations conducted using TRNSYS demonstrated that PVT integration reduced borehole length requirements by up to 45% and installation area by 53%. Energy savings reached 25.7%, while net present value increased by 13.2%. In Baghdad, the combined system delivered 155 MWh annually from the heat pump, accounting for 93% of total production, with an additional 45 MWh from thermal output. Seasonal performance factors in integrated systems showed a rising trend over 40 years, in contrast to a steady decline in standalone configurations. Ground temperatures dropped less drastically in PVT-supported scenarios, with a 35.83% reduction at 10-meter spacing in Baghdad, compared to 68.43% without PVT. PVT panels lowered surface temperatures by over 20°C and improved electrical efficiency by 9.5%. Solar electrical fraction peaked at 340% in July, showcasing surplus solar production. The system achieved a 408% renewable fraction during summer months. Investment analysis revealed that Scenario II-1 increased initial cost by 16.47%, yet reduced referenced cost by 27.14% through borehole optimization. In extreme climates like Mosul, energy demand for space heating reached 40.68 kWh/m 2 annually, highlighting the necessity for high-efficiency solutions. Results confirm that coupling PVT and GSHP technologies offers strong potential for sustainable thermal energy in dense residential areas, delivering improved efficiency, reduced operational costs, and enhanced ground sustainability across Iraq’s diverse climatic regions.