Optimization design of multi-sources significant temperature lift steam generating heat pump using renewable heat sources

Autocascade steam generating heat pumps (ASGHPs) offer a promising avenue for industrial decarbonization due to their capacity to achieve substantial temperature lifts when producing high-temperature steam from low-temperature air. However, conventional thermodynamic optimization methods often prove inadequate for maximizing ASGHP efficiency, primarily because they do not effectively address exogenous exergy destruction, particularly under non-steady operating conditions. This study proposed an exogenous optimization strategy based on advanced exergy analysis to enhance ASGHP performance through systematic integration of intermittent renewable heat sources such as solar energy to overcome this limitation. A multi-source ASGHP model was developed with optimized integration points, and its performance is evaluated across energy, exergy, economic, and environmental dimensions. Results demonstrated that the exogenously optimized ASGHP sequence—the compressor first stage, evaporator-condenser, and condenser—proposed via the advanced exergy method exhibits greater feasibility than conventional thermodynamic approaches. The proposed strategy increases the coefficient of performance (COP) by at least 28.64 % and enhances economic benefits by 59.63 %. Furthermore, intermittent utilization of low-temperature renewable heat sources boosts COP by 15.92 % and economic returns by 266.32 %. These results provide critical insights and theoretical guidance for optimizing significant temperature lift heat pumps powered by renewable energy sources.