Liquid air energy storage(LAES) technology stands out as a large-scale energy storage technology due to its superior energy storage density and adaptability to external energy sources. An LAES system that recovers waste cold of liquid ethylene and introduces an external low-temperature heat source is proposed. Moreover

thermodynamical and economic analysis on key parameters

including isentropic efficiency of the compressor and expander

and temperature of the heat source

are conducted. The results reveal that

when the ethylene flow rate is 34 t/h

the energy storage capacity can reach up to 5 MW/40(MW·h). At isentropic efficiency of the compressor and expander of 90%

the round-trip efficiency can achieve 77.45% by solely relying on an ambient heat source of 25 ℃ for air heating. When the heat source temperature is increased to 125 °C

the system's optimal round-trip efficiency

net present value

and dynamic payback period reaches 106.99%

144.73 million yuan

and 3.56 years

respectively. These findings provide reference for research on the coupling of LAES systems with external cold energy.