Thermodynamic design and analysis of air-liquefied energy storage combined with LNG regasification system

For cutting down the energy consumption and improving the cold energy conversion efficiency of the traditional liquefied air energy storage system (LAES), a novel energy system integration solution is proposed by combining the LAES with liquefied natural gas (LNG) regasification process. In this paper, the principal energy storage and energy release processes are simulated by Aspen Hysys. The influences of air mass flow rate and LNG regasification pressure on the performance are analyzed. The results indicate that the introducted system can attain 137.82 % round-trip efficiency, which is about 20 % higher than the conventional LAES system. Besides, the energy capacity reaches up to 10.87 MW and the exergy efficiency is 39.58 % during long-distance transportation. It's noteworthy that the power output in the liquefied air energy discharging period far exceeds the power generation from the organic Rankine cycle. The higher LNG transport pressure, the worse LNG-LAES system performance. When the air mass flow rate raises from 40,000 kg/h to 64,000 kg/h, the exergy efficiency is 3.4 % higher than the original, while the round-trip efficiency decreases by 29.79 %. Finally, through economic viability calculations, the dynamic recovery period of the LNG-LAES system is 5.41 years.