چكيده به لاتين
Energy storage is one of the most important subjects in the realm of electricity production optimization and electricity use such that nowadays different methods have become common for production management and energy use. Cold thermal energy storage is an important group in HVAC systems of buildings including encapsulated ice storage system and encapsulated cold storage system in hydrated salt. In this paper, performance of encapsulated ice storage system and encapsulated cold storage system in hydrated salt are analyzed during charging and discharging modes in partial storage strategy. In this study, thermodynamic, environmental and economic analyses are used. Energy and exergy analyses are the main parts of thermodynamic analyses. Environmental analysis and economic analysis consider the penalty cost due to electricity production and costs of the system respectively. Then, optimization of these systems are carried out by the aid of Non-dominated Sorting Genetic Algorithm, second edition (NSGA II) in MATLAB for a case study. Optimum values of decision variables are reported based on exergy efficiency and total annual cost as objective functions of the optimization. The optimization results show that total exergy efficiency of encapsulated ice storage system is 44.2% with total annual cost of 705364 [$/year]. While, total exergy efficiency and total annual cost of encapsulated cold storage system in hydrated salt are 47.77% and 413205 [$/year] respectively. Finally, sensitivity analysis of the optimization results of encapsulated ice storage system to the change in electricity unit cost is conducted.
Keywords: Cold thermal energy storage, Encapsulated, Phase change material, Hydrated salt, From onpeak to offpeak hours
