Research on the characteristics of photovoltaic-driven refrigerated warehouse system under different ice storage modes

Abstract

This research aims to explore the performance of ice storage modes in a photovoltaic (PV)-driven refrigerated warehouse. The ice storage modes were concisely clarified into series match (SM) and parallel match (PM), which were clearly defined and theoretically, experimentally and economically analysed under various working conditions and system configurations. The analysis reveals that the SM mode demonstrates an enhanced coefficient of performance (COP) under no and full-load conditions using utility electricity and PV power as energy supply, with COP for the vapour compression refrigeration cycle and whole PV-driven system reaching 2.66 and 0.28, respectively. The SM mode outperforms the PM mode in suppressing PV fluctuations, while the PM mode exhibits deficits of cooling energy consumption during variable solar irradiance. Therefore, the SM mode excels in suppressing PV fluctuations and saving more cooling capacity compared to the PM mode. In addition, the PV system is more energy-efficient than a utility-electric driven system, and the economic cost of the SM mode is lower than that of the PM mode. Furthermore, the feasibility of suppressing PV fluctuations in the SM mode was verified by preserving 1500 kg of green grapes for 14 consecutive days. Results indicate that maintaining the storage temperature of the system at 5 °C prevented a decrease in grape quality, resulting in a 5.186 % decrease in water content and a 3.61 % decrease in sugar content.