Comparative study on four autocascade refrigeration cycles based on energy, exergy, economic and environmental (4E) analyses

•An ejector enhanced autocascade cycle with two-stage component separation is raised.•The novel cycle and other three autocascade cycles are compared by 4E analyses.•The novel system owns obvious performance improvement over other three cycles.•The effects of main operation parameters on the novel cycle performance are analyzed.•The novel cycle owns the longest payback period and lowest full life cycle cost.