CO2跨临界热泵系统热力性能提升与经济性分析

CO₂跨临界热泵系统热力性能优化，往往其设备的初始投资成本会增加，在设备生命周期内其对总体费用的影响不明确。本文建立了常规CO₂跨临界热泵系统（BASE）、CO₂双级压缩热泵系统（TSCHPS）和CO₂/CO₂机械过冷热泵系统（MSHPS）的热力学与经济学模型，其中在经济学模型中定义了综合考虑设备初投资及运行费用的目标函数，研究了3种热泵系统在小温差风机盘管、地暖以及暖气片作为散热终端下热力性与经济性之间的关系，讨论了系统升级后的生命周期经济性变化。研究结果表明：在3种散热终端的系统名义工况下，TSCHPS、MSHPS的能效比（COP）均比BASE系统提升15%以上，但其生命周期经济性却不一定得到改善；BASE系统热力性与经济性之间相互关联，TSCHPS、MSHPS的热力性与经济性之间关联性不强；系统升级后的经济性变化与蒸发温度及供热量有关，给出了3种散热终端下不同应用范围内经济性最优系统。

Thermodynamic performance improvement and economic analysis of CO2 transcritical heat pump system

The optimization of the thermodynamic performance of the CO₂ transcritical heat pump system often increases the initial investment cost of the equipment, and its impact on the overall cost during the equipment life cycle is unclear. In this paper, thermodynamic and economic models of conventional CO₂ transcritical heat pump system (BASE), CO₂ two-stage compression heat pump system (TSCHPS), and CO₂/CO₂ mechanical subcooling heat pump system (MSHPS), were established. In the economic model, the objective function was defined via considering the initial investment and operation cost of the equipment. The relationship between the thermodynamics and economy was studied through using three heat pump systems with small temperature difference fan-coil unit (STD-FCU), floor-coil radiator (FCR), and traditional designed radiator (TDR) as heat dissipation terminals. The economic change during the life cycle after the system upgrade was discussed. The results showed that the COP of TSCHPS and MSHPS were both improved by over 15% than that of the BASE system under the system nominal conditions of the three heat dissipation terminals, but their life cycle economy is not necessarily improved. There is a correlation between the thermodynamic performance and economy of the BASE system, but the correlation between the thermodynamic performance and economy of TSCHPS and MSHPS is not strong. The economic change after the system upgrade is related to the evaporation temperature and heat capacity, and the best economic system in different application ranges under three heat dissipation terminals is provided.