A novel hybrid ice storage design applicable for commercial showcase with refrigerator and freezer

Abstract

In this research, a novel hybrid design of ice storage system is proposed in a showcase with refrigerators and freezers. The design concept and performance of the hybrid ice storage system are demonstrated and analyzed in detail. The cold energy is stored in the ice storage tank during off-peak hours, and the cold energy is released during peak hours. This study uses the combination of internal and external melting to supply the cold energy in the ice storage tank, and to the refrigerator and freezer at the same time. It is found that the ice storage system can employ ice melting to reduce the condensation temperature during peak hours, which can effectively improve the coefficient of performance of the refrigerator system (COP). The COP of the freezer and refrigerator system is approximately 2.053 and 2.579 for the refrigerated mode and they were further improved to 2.806 and 4.449 respectively in ice melting mode. The experimental results show that the ice storage system in this research consumes more energy than the general system. However, the design can have 10 % electricity expenditure saving. During the peak period, 22 % of the electricity consumption can be transferred to the off-peak electricity consumption. Yet, the ice storage system can be successfully applied in refrigerator and freezer cabinets with the loading temperatures of 4–7 °C for refrigerator and − 12 to −9 °C for freezer. Note that none of the existing studies were reported with the ice storage systems that are capable of demonstrating cold storage below 0 °C.