Comparison of performance of compressed-air energy-storage plant with compressed-air storage with humidification

Abstract

In this work, the use of compressed-air storage with humidification (CASH) system, instead of using the compressed-air energy storage (CAES) system, to increase the generated power (W_gen) and primary energy efficiency (η_pe) is discussed. Performance is calculated for CAES and CASH systems. The operating variables in this study are discharged air mass flow (m_t), ambient air temperature (T_a), and overall pressure ratio (Rc). The effect of these variables on the generated power (W_gen), energy ratio (ER), and primary energy efficiency (η_pe) is evaluated. The efficiencies are based on lower heating value.

The result showed superior performance of CASH system relative to CAES. For example, at m_t= 200 kg/s, W_gen= 243.029 MW, ER = 45.41 per cent, η_pe= 43.2 per cent for the CAES; whereas for the CASH system, W_gen= 277.083 MW, ER = 39.8 per cent, η_pe= 47.1 per cent.

The generated power (W_gen), energy ratio (ER), and primary energy efficiency (η_pe) for the CASH system at the design point, are about 14 per cent more, 14 per cent less, and 9 per cent more than that for the CAES system, respectively.