Energy, exergy, and economic analysis of cold energy storage systems in cold storage using polyethylene glycol phase change material

The cold energy storage system using phase change materials (PCMs) is an effective method for reducing energy consumption in cold storage facilities. Its primary objective is to optimize the management of energy storage and consumption. The cold energy, generated from the produced condensate in cold storages, is utilized to cool the air and pre-cool the products. This paper investigates the energy, exergy, and economic performance of both the charge and discharge processes of the energy storage system, as well as the overall integrated system. The aim is to identify and design an efficient cooling energy storage system for cold storage applications. Based on the temperature range of condensates from cold storage and the physical properties of phase change materials, polyethylene glycol 600 has been selected as a suitable PCM for this study. The effect of several parameters, including volumetric flow rate, temperature and humidity of the incoming air to the cold room evaporator coil and the cooling capacity of the cold room refrigeration system, on the energy and exergy efficiency of the process of charging, discharging and energy storage system investigated. The results show that by increasing all these parameters, the energy efficiency and exergy of the charging, discharging and energy storage system are slightly improved. This increase in efficiency varies from 4 to 10 percent. The study of the effect of the cooling capacity of the cold room refrigeration system on the annual cost of the whole system also shows that with the increase of the cooling capacity of the cold room refrigeration system, the annual cost of the whole system increases.