由曹祥、张春路（通讯作者）和张子杨撰写的论文Stepped pressure cycle – A new approach to Lorenz cycle在国际制冷学报International Journal of Refrigeration, 2017年第74卷在线发表。论文首次提出了蒸气压缩式梯级吸排气循环的概念，并从理论上证明了N级梯级吸排气循环可以逼近变温热源最高效率的Lorenz循环。通过数值计算及实验系统的初步测试，证实了梯级吸排气循环巨大的节能潜力。本文研究为发展高效的蒸气压缩式制冷/热泵系统提供了一条切实可行的新途径。（注：本文工作受到国家自然科学基金项目“梯级吸排气制冷循环与系统特性的基础研究”资助）

论文链接：http://www.sciencedirect.com/science/article/pii/S0140700716303462

免费下载链接：https://authors.elsevier.com/a/1U6TuV-TmDmHc(有效期至2017年1月14日)

论文摘要：

Refrigerant vapor-compression cycle usually works with variable temperature heat sources in reality, which causes remarkable irreversible losses in heat exchange process. This paper proposed the stepped pressure cycle to modify the vapor-compression cycle using refrigerant, particularly pure refrigerant. Refrigerant is designed to flow through a series of heat transfer units with stepped pressures so that the irreversible losses can be reduced. Theoretical proof confirmed the stepped pressure cycle with pure refrigerant can approach the Lorenz cycle, the most efficient cycle under variable temperature heat sources. Numerical analysis on cycle performance demonstrated that a dual-step suction and discharge pressure cycle using R32 can achieve 11.5% cooling COP improvement for residential air conditioner, while a dual-step discharge pressure cycle using R134a can bring 9.8% heating COP increase for heat pump water heater. A pilot system was made and preliminarily tested. Compared to the single cycle system, 12.3% and 18.7% COP increase were achieved in the pilot system by applying dual and triple subcycles, respectively.