Development and experimental analysis of CO2 heat pump for DHW production.

This study presents results of two experimental campaigns on a 30 kW air source CO2 heat pump prototype for domestic hot water (DHW) production. The prototype has been realized, tested and optimized within the NxtHPG (Next Generation of Heat Pumps working with Natural fluids), 7th Framework European project. The project aims to reach higher efficiency (10-20% SPF improvement) and lower Carbon footprint (20% lower TEWI) than the current state of the art HFCs/HFOs or Sorption heat pumps, with costs very similar or slightly higher than the latter systems (10%). The tested CO2 heat pump has been designed to produce water at 60 °C/80 °C starting from a return temperature in the range 10 °C/55 °C (winter) and 20 °C/55 °C (summer). First experimental campaign was performed to determine possible issues and potential improvements to be applied on this prototype. In the second experimental campaign, after the required modifications of the prototype, the measured performance, COP and heating capacity, have been in line with objectives. In addition, useful information have been obtained to make additional modifications to further improve the heat pump performance.

本研究针对用于生活热水（DHW）制备的30 kW空气源二氧化碳（CO₂）热泵样机，报道了两次试验研究的相关结果。该样机系在欧盟第七框架研究计划项目NxtHPG（Next Generation of Heat Pumps working with Natural fluids）框架下研发、测试并优化完成的。本项目旨在相较于当前主流的氢氟烃（HFCs）/氢氟烯烃（HFOs）工质热泵或吸附式热泵（Sorption heat pumps），实现更高的能效：季节性能系数（Seasonal Performance Factor，SPF）提升10%~20%，同时降低碳足迹，总等效温室效应（Total Equivalent Warming Impact，TEWI）降低20%，且成本仅比后者略高或基本持平，涨幅不超过10%。本次受试的二氧化碳（CO₂）热泵样机设计可基于冬季工况下10 ℃~55 ℃、夏季工况下20 ℃~55 ℃的回水温度，制备出水温达60 ℃~80 ℃的热水。首次试验旨在排查该样机存在的潜在问题，并探索可行的优化方案。在完成样机必要的改进后，研究团队开展了第二次试验，实测得到的性能系数（Coefficient of Performance，COP）与制热容量均符合项目预期目标。此外，本次试验还获取了可供后续进一步优化该热泵性能的有效参考信息。