The stepped pressure cycle has been proven high energy-saving potentials in refrigeration and heat pump applications. However, recently we found that the conclusion of energy-saving is conditional on the evaporator superheat. To in-depth understand the effect of evaporator superheat on stepped pressure cycle performance, we did investigation by using the analytic method, numerical analysis and lab experiment in this paper. Theoretical proof confirmed that the dual suction pressure (DSP) cycle can always achieve higher COP (coefficient of performance) than the simple cycle at zero superheat. When parallel-flow evaporators are used and the superheat exists, the DSP cycle still reaches higher COP than the simple cycle at the same superheat. Maximum 9.0% COP improvement with 4K superheat was found in the lab test. However, with counter-flow evaporators, the DSP cycle can be less efficient than the simple cycle at large superheat. Moreover, the inherent relation between the COP improvement and the uniformity of temperature difference field in evaporators was discussed.

在制冷和热泵应用中，阶梯式压力循环已被证明具有很高的节能潜力。但是，最近我们发现，节能的结论取决于蒸发器的过热度。为了深入了解蒸发器过热对阶跃压力循环性能的影响，我们采用分析方法，数值分析和室内实验进行了研究。理论证明证实，在零过热状态下，双吸压（DSP）循环始终可以比简单循环获得更高的COP（性能系数）。当使用平行流蒸发器并且存在过热时，在相同的过热情况下，DSP循环仍比简单循环达到更高的COP。在实验室测试中，发现4K过热可使COP最高提高9.0％。然而，使用逆流蒸发器，DSP循环的效率可能比过热较大的简单循环要低。此外，还讨论了COP改善与蒸发器温差场均匀性之间的内在联系。