The development and performance evaluation of an alternative energy-based hybrid cold storage system

The development of cold storage systems with solar-integrated thermal energy storage (TES) could be an exciting alternative energy solution to fossil fuel-based cold storage. For this novel technology to be commercially applicable, significant scientific research is required. Although few attempts have been made in this area, the limitations of existing studies encourage further investigation to advance the field. This research aims to develop a solar-based hybrid cold storage (SHCS) system and perform the techno-economic analysis (TEA) of the system to address the existing research challenges and enhance the understanding of commercial applications. An SHCS of L 4.88 m × W 2.44 m × H 2.44 m has been developed by integrating 500 kg phase change materials (PCM) of ethylene glycol aquas solution, as latent thermal energy storage (LTES), to store energy and provide backup during off-solar time. Three different modes of the power system, Latent Thermal Energy Storage (LTES)-based, Electrochemical Energy Storage (EES)-based (Battery), and no storage; and three types of construction materials, sandwich polyurethane (PUR) panels, sandwich expanded polystyrene (EPS) panels, and concrete were considered in the TEA of the SHCS. The power mode with LTES showed a nearly 1.5 years shorter payback period and 130 % higher net present value (NPV) than the EES mode. The solidification and melting characteristics of the LTES system are uniform at different levels during charging and discharging, which may enhance the heat transfer rate. The PCM system is remarkable in that it maintains a storage temperature of 3 °C in the fresh food chamber for approximately 13 h without an external source of energy. Regarding the construction material of SHCS, sandwich PUR panels outperformed concrete owing to their lower density (40 kg/m³), improved thermal insulation, and modular nature, though the rate of return of PUR panels is slightly lower (0.26 % and 0.81 %) than its counterparts due to its higher initial cost. Overall, it was found that PUR panel-made SHCS integrated with an LTES system provides better techno-economic performance when energy storage is necessary and could be considered to scale up the system in the future for commercial application.