由成家豪、何宇佳、张春路（通讯作者）撰写的论文New scenario of CO2 heat pump for space heating: Automatic mode switch between modified transcritical and cascade cycle in one system在Applied Thermal Engineering 2021年第191卷在线发表。论文巧妙地在同一CO2热泵供热系统中实现了过热回收复叠循环和机械过冷跨临界循环两种运行模式，并探讨了系统设计和模式切换中的关键技术问题，实现了全工况下的系统高效运行，对于这类新型CO2热泵供热系统的推广应用具有指导意义。本文工作受国家自然科学基金项目“基于拓扑同胚循环构造与换热器网络化重构的二氧化碳热泵供暖系统原理及应用”的资助。

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论文摘要：

Hot water production and space heating consume huge amounts of energy. CO2 heat pump has been proven more efficient in hot water production, but less efficient in space heating. In the paper, we proposed a new scenario of CO2 heat pump for space heating. Wherein the same system can automatically switch between transcritical cycle with dedicated mechanical subcooling (DMS) and cascade cycle with desuperheating heat recovery (DHR), making it possible to combine the advantages of transcritical and cascade system in different ambient conditions and heating terminals. With the aid of modeling and simulation, main application concerns on system design and operation are discussed. Recommendations for matching design of key components are made. A correlation for automatic mode switch is developed. At last, the proposed scenario is numerically evaluated with weather data of six typical cities in China, verifying the improvement of at most 8.7% and 19.4% in the whole heating season compared to transcritical system with DMS and cascade system, respectively.