Analysis of Coupled Liquid Air Energy Storage and Liquefied Natural Gas Cold Energy Cascade Utilization System

The vaporization of liquefied natural gas (LNG) liberates a substantial quantity of cold energy. If left unutilized, this cold energy would cause significant energy waste. Currently, both domestic and international cold energy utilization strategies are rather simplistic and unable to fully capitalize on the wide temperature range feature inherent in LNG cold energy. This study presents a three-tiered cold energy utilization system that integrates liquid air energy storage (LAES), cold energy power generation, and cold energy air conditioning. Moreover, during the LNG vaporization process, the thermal discharge from the power plant is utilized as a heat source to boost energy utilization efficiency and environmental performance. This research develops thermodynamic and economic evaluation models for the coupled system. It uses Aspen HYSYS V14 software to conduct process simulation, analyze cycle efficiency and exergy efficiency, and assesses the system’s economic feasibility by applying the net present value (NPV) method, which is based on the regional electricity prices of an LNG receiving station in Tangshan. The results show that the system attains a cycle efficiency of 105.83% and an exergy efficiency of 55.89%, representing a 6.18% improvement over traditional LAES systems. The system yields an annual revenue of CNY 77.06 million, with a net present value (NPV) of CNY 566.41 million and a capital payback period of merely 2.53 years, demonstrating excellent economic feasibility. This study offers crucial references and a foundation for the engineering application of LNG cold energy in energy storage and power plant peak regulation.