Comparison of Control Methods and Performance Evaluation of the Combination System of PVT and GSHP for Greenhouse Applications

Ground source heat pump (GSHP) systems face long-term ground temperature decline and COP reduction due to imbalanced heating and cooling loads, which are further exacerbated in high-heating-load environments such as greenhouses. Additionally, conventional flat-plate and evacuated tube collectors utilize solar energy only as heat, limiting overall system efficiency. This study proposed a PVT-GSHP system that integrated photovoltaic thermal (PVT) technology to address these challenges and developed a solution tailored for greenhouse environments. Using TRNSYS 18, the conventional GSHP system (Case 1) was compared with two PVT-GSHP configurations (Case 2 and Case 3). Case 3 demonstrated a BTES heat emission of 47.18 MWh and a heat storage capacity of 16.63 MWh, maintaining stable ground temperatures over five years. In addition, GSHP power consumption in Case 3 was reduced by 11.5% compared to that in Case 1, with the PVT system generating 14.54 MWh of thermal energy and 7.28 MWh of electricity, offsetting 36.4% of the GSHP's energy consumption. Finally, the PVT system reduced CO₂ emissions by 6444.8 kg_CO₂, equivalent to the annual absorption of 658 pine trees, demonstrating its effectiveness in greenhouse gas mitigation.