Enhancing energy efficiency of air conditioning system through optimization of PCM-based cold energy storage tank: A data center case study

Phase change material (PCM)-based cold energy storage systems (CESS) offer a promising solution for improving energy efficiency and cost-effectiveness in air conditioning systems. However, their limited heat transfer efficiency hinders widespread adoption. This study focuses on investigating the impact of key factors, including plate size, arrangement, and fin structure, on the charging and discharging processes of a PCM-based CES tank. The findings highlight the significant influence of PCM plate configuration and inlet flow rate on heat transfer performance in the storage tank. Notably, reducing the height of PCM plate from 50 mm to 10 mm while maintaining a consistent volume resulted in a remarkable reduction in charging/discharging time by 84.6 % and 87.9 %, respectively. Response surface models were developed to establish correlations between the number of fins, plate height, and inlet flow rate with the charging/discharging time of PCM plates, enabling the identification of the optimal solution for achieving faster charging/discharging times. Moreover, a case study in a data center retrofit project was conducted to evaluate the thermal performance of different PCM plate configurations. Despite the higher initial investment, the optimized solution demonstrated a higher effective utilization rate of the PCM-based CESS, leading to substantial energy savings and reduced carbon emissions.