Performance analysis and multi-objective optimization of PV/T coupled transcritical CO2 heat pump under wide temperature range conditions

The photovoltaic/thermal (PV/T) coupled heat pump system has attracted considerable attention because of its potential energy, environmental, and economic benefits. In this study, simulation models were developed for two configurations of PV/T coupled transcritical CO 2 heat pump systems: a water-source (PV/T-WSHP) and a dual-source (PV/T-DSHP) system. These models were employed to systematically simulate the systems' operational characteristics under three typical winter conditions in Xinjiang, China: sunny, cloudy, and cold sunny days. Furthermore, the influence of environmental parameters on system performance was investigated, and a multi-objective optimization of the key performance for the dual-source system was performed. Results show that, compared to their performance under cloudy conditions, the performance of the PV/T-DSHP and PV/T-WSHP systems under sunny winter conditions is higher. Their PV/T components offer significant power generation advantages, achieving daytime self-sufficiency rates of 63.3% and 66.7%, respectively, as well as a surplus energy. At low temperatures ranging from -28.1 to -19.8 °C, the PV/T-DSHP and PV/T-WSHP systems still maintain high performance, with the average coefficients of performance ( COPs ) reaching 2.41 and 2.48, respectively. Furthermore, based on multi-objective optimization and the Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) decision-making method, this study systematically reveals the synergistic optimization characteristics of the energy efficiency, emissions, and cost of PV/T-DSHP under typical winter conditions.