Performance analysis of a novel hybrid solar photovoltaic - pumped-hydro and compressed-air storage system in different climatic zones

Abstract

It has been proven that the future of energy demands for human society is related to renewable energy sources such as solar energy. However, the operation of solar energy systems is associated with some challenges, such as naturally uncertainty, instability, and intermittently at different hours of the day, which has caused problems with their widespread use. One of the most innovative ways to overcome these challenges is to use energy storage systems. The Pumped-Hydro and Compressed-Air (PHCA) system is a new energy storage system which can be coupled with power generation from renewable energy sources such as wind and solar. The aim of the present study is to evaluate the performance of the PHCA system is coupled with power generation from photovoltaic (PV) system from the energy and exergy points of view. The proposed energy system is able to generate electricity and storing energy. The solar PV system absorbs solar energy and converts it to the electricity. This electrical energy is then fed to the pump of storage system. Then, the required energy is produced by the turbine of storage system when needed. To examine the energy system performance, two different scenarios are considered: the first determines the required number of solar PV panels for a constant capacity of the PHCA storage system. In the latter, the storage system volume is determined for a solar PV system with a capacity of 1 kW. To evaluate the energy system performance the climatic conditions of two different cities in the Middle East (Dubai and Yazd) are considered. The results of the scenario I revealed that, the required pump work, which must be supplied by solar PV system, is equal to 3.69 and 4.0 MJ/m3 for isentropic and isothermal processes, respectively. In such a context, the total efficiency of the energy system is equal to 63.75%. In addition, the total exergy destruction of energy system for isentropic process is 8.36% and 8.39% less than that isothermal process in Dubai and Yazd, respectively. From scenario II, it was fond that the storage system should have a fixed capacity of 7.79 and 7.19 m3 for isentropic and isothermal processes, respectively. Based on research findings engineers must establish the right balance between the storage system and the solar system according to the energy needs for storage, storage volume, storing water method, and hours of operating and geological requirements.