Decarbonizing industrial process heat: energy, economic, and environmental analysis of a high-temperature solar-assisted heat pump using low GWP refrigerants

Decarbonizing high-temperature industrial processes is essential to achieve global climate neutrality by 2050. This study evaluates the technical, energy, economic, and environmental performance of solar-assisted heat pumps (SAHPs) for industrial laundry applications, including hot water production at 80 °C and pressurized water (steam economizer) at 140 °C. A validated simulation framework was developed to analyze up to 130 combinations of system configurations and refrigerants. Eight configurations were assessed, comparing single-stage (SS) and two-stage cascade (TSC) cycles using ambient air or solar collectors as heat sources. Low-global warming potential (GWP) refrigerants, including hydrofluoroolefins (HFOs) such as R1233zd(E) and R1336mzz(Z), and hydrocarbons such as R600 and R601a, were considered. For hot water production, solar-assisted systems provide more stable performance than air-source configurations, with photovoltaic-thermal heat pumps (PV/T HP, SS) achieving the highest COP values (3–5), depending on refrigerant and climate. For steam generation, only PV/T HP TSC configurations are technically feasible, with COP values of 1.6–2.0. Economic analysis, compared with conventional gas boilers, systems using R1233zd(E) and R600 achieve the highest profitability, with payback periods of 3.5–7 years over a 20-year lifetime. The best configurations reduce CO 2 emissions by up to 50 %. Overall, optimal system design requires balancing energy efficiency and investment costs, with specific refrigerant–cycle combinations outperforming fossil-fuel technologies across different climates.