Exergoeconomic optimization of a solar driven system with reverse osmosis desalination unit and phase change material thermal energy storages

The goal of the current article is to suggest a novel solar system to produce power, fresh water, and cooling. As solar energy is unavailable at nights, a novel thermal storage system (TES) based on phase change material (PCM) is used to store the required energy for night demands. The main novelty of the current configuration for the PCM is on the dynamic modelling of the PCM to capture the performance of the system during a day and perform the exergoeconomic analysis. After receiving the solar energy, a gas turbine and a Kalina cycle would supply the electricity of the grid. Additionally, the cooling capacity would be provided by the LNG stream for the domestic users, while reverse osmosis (RO) unit would produce the fresh water. To examine the performance of the system, the output parameters of the exergoeconomic analysis in addition to exergy destructions for each sub-system are computed. The output results indicate that the exergy efficiency is about 21.19%, while that of the energy is 41.00%. The cooling load of the suggested system is also 0.709 MW, while the rate of generated electricity and fresh water are 5.73 MW and 7905.7 m3/day, respectively. The exergoeconomic analysis also showed that the total cost rate of the system is equal to 25.20 $/GJ, and the levelized cost of electricity is 0.1275 $/kWh. Moreover, the impacts of input parameters on the respective output parameters are analyzed and optimized to reach the best performance of the system. Results indicated that the gas turbine’s pressure ratio should be approximately 8, while the needed values for the basic ammonia concentration and LNG pressure ratio are about 0.53 and 8.23, respectively.