Research progress on model and optimization of solar-assisted heat pump systems

With rising global temperatures, deteriorating environmental conditions and energy shortages, countries around the world are actively developing renewable energy. The combination of solar energy and heat pumps is an important way for the development of new energy utilization technologies, including the solar-assisted heat pump system supplying hot water, heating and drying. Reviews the research progress of solar-assisted heat pump systems from the aspects of structure, model, exergy analysis and optimization improvement. Puts forward the suggestions for the further research direction of solar-assisted heat pump systems. There is still much research space in terms of improving system performance and reducing costs.