GREATLAB最近在International Journal of Refrigeration上连续发表两篇关于跨临界二氧化碳制冷/热泵系统的研究论文。论文简介如下：

由梁星宇、成家豪、何宇佳、王磊、李慧、邵亮亮和张春路（通讯作者）撰写的论文Study on annual energy performance of transcritical CO2 heat pump water heating systems in Shanghai 在International Journal of Refrigeration 2019年第107卷在线发表。论文基于实地调研与仿真分析相结合，研究了二氧化碳热泵热水器在上海的实际运行情况，发现实际运行能效远低于设计值（注：这也是制冷空调设备实际运行中普遍存在的严重问题！值得引起全行业的高度重视并制定有效的对策！）。对此，论文分析了其原因并给出了改进建议。

论文链接

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论文摘要：

CO2 heat pump water heating is an energy-efficient technology and being widely applied in Shanghai. However, its energy efficiency after long-term operation has not been well evaluated so far. In this paper, the energy efficiency and potential issues of CO2 heat pump water heater after multi-year service are in-depth investigated. In-situ study of CO2 heat pump water heating systems in Shanghai was carried out. Operating data were collected and field test was conducted. A typical case was chosen for comprehensive analysis. The results show that the annual performance factor (APF) of the actual system is 2.57, relative to 4.12 in its perfect shape. To find out what happened to this system, a simulation model was developed, calibrated and validated with field test data and operating data. In terms of simulations, suggestions were made on the system design and control for long-term performance improvement.

由梁星宇、何宇佳、成家豪、邵亮亮和张春路（通讯作者）撰写的论文Difference analysis on optimal high pressure of transcritical CO2 cycle in different applications在International Journal of Refrigeration 2019年第106卷在线发表。最优高压控制一直被认为是跨临界二氧化碳系统高效运行的关键，论文基于响应面方法研究了跨临界二氧化碳循环在制冷和制热应用上的最优高压特性。研究表明，对于制冷应用而言，气冷器出口制冷剂温度是主导性影响因素，达到96.38%的贡献率；而对于制热应用而言，多个参数都对最优高压有重要影响，其中供热温度的影响最大，但也只达到55.42%的贡献率。因此，论文针对制热应用提出了从单变量到四变量的多种高压控制方程，并给出相应的误差估计。

论文链接

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论文摘要：

Optimal high pressure has a key role in transcritical CO2 system performance. In this work, we conducted a quantitative difference analysis on optimal high pressure between CO2 refrigeration system and heat pump water heater (HPWH) using response surface methodology. It revealed that temperature of CO2 leaving gas cooler, with 96.38% contribution, is the predominant factor to optimal high pressure in CO2 refrigeration system. However in HPWH, multiple factors affect optimal high pressure. Water outlet temperature, evaporating temperature, pinch point temperature difference and water inlet temperature account for 55.42%, 25.65%, 5.67%, 3.72% contributions, respectively. Furthermore, new quadratic correlations for HPWH with different number of variables were developed. As a result, when the number of variables increased from 1 to 4, mean error of COP almost linearly decreased from 5.28% to 0.22%.