Design and Simulation Analysis of a Small-Scale Compressed Air Energy Storage System Directly Driven by Vertical Axis Wind Turbine for Isolated Areas

Abstract

Increasing interest is being paid to the exploitation of wind power to supply stable electricity for the microgrid. The microgrid system coupled with wind turbines is available to generate power for local residents, especially in isolated areas. Being suitable for a microgrid, a 30-kW compressed air energy storage (CAES) system directly driven by a vertical axis wind turbine (VAWT) is presented in this paper. A high-pressure storage tank was used to store the compressed air in order to guarantee continuous operation. In addition, a control strategy was designed for the system to make full use of wind energy and enhance system stability. Moreover, a mathematical model was established to simulate the system with hourly wind speed data, which were randomly selected from Zibo in the Shandong province of China. Variations in gas turbine temperature, operation pressure, and the mass flow rate of compressed air with wind speed over two weeks in winter and two weeks in summer are shown in the paper. The results indicate that the adoption of the VAWT control strategy enables the round-trip efficiency to increase by 5.21% and the number of hours in the protection mode to decrease by 22 h in four weeks. Moreover, the system absorbed zthe fluctuant wind power and generated stable output (30 kW) for consumption.