A direct-drive PV pump system based on phase change heat storage is proposed to address the current building energy consumption problem in heating/cooling. The system can solve the problems of unstable solar energy, high battery cost, and short battery service life. Taking a 45m 2 office in Shanghai as the research object, the annual dynamic simulation model of the system is built through TSNSYS. The linear weighted evaluation function method is used for multi-objective optimization analysis of system performance and cost. The results show that the selection scheme with a PV area of 26 m2, a phase change volume of 0.14 m3, and a valley electricity storage ratio of 1 has the best-combined performance and cost of the system.

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The large consumption of nonrenewable energy has caused energy shortages and environmental climate problems, and improper food storage has caused a large amount of food waste. To solve the problem of energy shortage and waste in grain transportation, a photovoltaic direct-drive refrigeration compartment based on apple transportation is designed. The design adopts a 15-foot refrigeration compartment and uses lightweight crystalline silicon PV modules to reduce the overall weight of the refrigeration compartment. According to the room size, eight parallel PV modules are selected for power generation. In conjunction with the PV modules, the rated power of the chosen compressor is 2.6 kW. Based on the storage conditions of apples, the design storage temperature is 0 °C, and HM-EO-2 is used as the refrigerant for cold storage. According to the transportation requirements of apples, the designed cold storage capacity of the cryogen should meet the 48h cold load. The mathematical models of the cold load of refrigeration compartments, refrigerant storage, and solar irradiation are established, which verify that the refrigeration system is correctly selected, and the critical parameters of the cold storage system are designed. It is calculated that the maximum hourly cold load and the daily total cold load of the refrigeration compartment are taken on June 29. The maximum hourly load is 1.355 kW, and the daily total load is 16.781 kW. The selected compressor can meet the real cooling demand.

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