Analysis of the performance of a refrigerated display cabinet fitted with a thermosiphon thermal accumulator for demand-side management

Abstract

Demand-side management (DSM) is a key strategy for regulating electricity demand, especially in grids incorporating renewable energy sources. Like electrical batteries, thermal energy storage acts as a flexible load to alleviate grid stress. Therefore, to support demand response programs, an innovative Thermosiphon Thermal Accumulator (TTA) has been developed and integrated into vapour compression refrigeration systems to store and supply cold energy to the evaporator during power cuts. This article examines the performance of the TTA, integrated into a closed-door refrigerated display cabinet, during a 1.5-hour DSM event under varying operating conditions, using five key performance indicators. The results show that the accumulator successfully supplied cold energy to the evaporator during power cuts, while also mitigating product temperature rise during DSM event, ensuring compliance with regulatory temperature limits under all tested conditions. For all experiments, energy consumption during DSM with accumulator discharge was comparable to regular operation, with even a slight reduction (up to 7 % lower in some cases). This decrease in energy consumption is attributed to the lasting impact of DSM-related savings, which outweigh the short-term rebound effect. Experiments involving high thermal loads required up to 8 h to recharge the accumulator after DSM due to defrosting cycles. Interactions between door openings, defrost cycles, and thermostat settings were observed in some cases. With an ambient temperature of 19 °C, a thermostat setting of −1 °C, and 50 % product occupancy, the TTA can sustain two to three 1.5-hour DSM events in 24 h.