Life-cycle thermo-economic-environmental analysis of a PV-driven heat pump with and without refrigerant leakages

Achieving near-zero emissions by 2050 requires residential air-conditioning systems to integrate renewable energy sources, aligning with energy community principles. Additionally, the forthcoming F-Gas regulation will phase out fluorinated gases in domestic heat-pumps, promoting natural refrigerants like propane. However, heat pump performances may degrade up to 50 % overtime due to undetected soft faults, such as refrigerant leakage. These aspects make the optimization of future small-scale heat pumps coupled with renewables challenging, since optimal total cost and environmental impact solutions may diverge. This paper presents a multi-criteria analysis for a 2.5 kW domestic heat-pump driven by photovoltaic solar panels. A preliminary design optimization compared two refrigerants, R32 and propane, by permuting several design parameters, revealing 25–32 % lower production costs for R32 compared to propane. Optimal designs were then simulated over their lifetime, considering varying photovoltaic panel and battery sizes, European climates and refrigerant leakage scenarios. Results confirm a misalignment between cost-minimizing and environmentally optimal solutions, underscoring the need for incentive politics aimed at reducing design costs. However, these policies may be insufficient under high refrigerant leakage scenarios, having 11 %–20 % cost increase, and 70 %–85 % life cycle climate performance increase with the fault-free case. Therefore, fault detection, diagnosis and evaluation strategies become essential.