Novel Steam Constant-Pressure Pumped Hydro with Compressed Air Energy Storage System and Thermodynamic Analysis

In view of off-design working condition characteristics of the original pumped hydro compressed air (PHCA) system, and based on previous research of PHCA, a novel steam constant-pressure pumped hydro combined with compressed air energy storage system is proposed. The system realizes constant pressure discharge process by using the latent heat and sensible heat released from steam, and steam also serves as working fluid after condensation, which improves energy capacity and energy density of whole system. Following the second-law of thermodynamics, the system performances are analyzed with focus on the dependence of energy efficiency and energy density on each parameter, and the exergy loss of the equipment in each part of the system is evaluated. The results show that with the increasing initial pressure, energy density of the system increases gradually, but the total efficiency decreases; with the increasing volume of a single cylinder, the total efficiency and energy density of the system reach the minimum and maximum successively; the exergy loss of steam generator and cylinder gets the highest. © 2021, Editorial Office of Journal of Xi'an Jiaotong University. All right reserved.