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 ( Wgen) and primary energy efficiency (ηpe) is discussed. Performance is calculated for CAES and CASH systems. The operating variables in this study are discharged air mass flow (mt), ambient air temperature ( Ta), and overall pressure ratio (Rc). The effect of these variables on the generated power ( Wgen), energy ratio (ER), and primary energy efficiency (ηpe) is evaluated. The efficiencies are based on lower heating value. The result showed superior performance of CASH system relative to CAES. For example, at mt= 200 kg/s, Wgen= 243.029 MW, ER = 45.41 per cent, ηpe= 43.2 per cent for the CAES; whereas for the CASH system, Wgen= 277.083 MW, ER = 39.8 per cent, ηpe= 47.1 per cent. The generated power ( Wgen), energy ratio (ER), and primary energy efficiency (ηpe) 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.