Design and Modelling of Heat-Coupled Storage System with High- and Low-Pressure Bypass: Electrothermal Characteristics and Peak Regulating Performance

Abstract

To achieve a balance between supply and demand during cogeneration system operation, it is necessary to improve the peak regulation capacity and regulatory flexibility of the unit. Considering the excellent performance of energy storage systems, a heat-coupled storage system with high- and low-pressure bypass is proposed to increase peak regulation capacity. Employing a 300 MW heating unit as the research object, thermal system models of a traditional-pumping steam-heating system, a high- and low-pressure bypass heating system, and a coupled system were built using Aspen Plus software. The electric heating characteristics of the three systems, as well as the peak regulation capacity and peak regulation depth of the coupled system, were analysed under different storage and heat release loads. Results indicate that the high- and low-voltage bypass system and the coupled system both improve the peak capacity and control flexibility of the unit. Moreover, the coupled system has a greater influence on the maximum thermoelectric ratio and minimum charge rate than the high- and low-voltage bypass heating system, thereby extending the range of safe operation. The peak capacity and depth of heat storage are 65.55 MW and 21.85%, respectively, while the peak capacity and the depth of the heat-release process are 39.32 MW and 13.10%.