中文摘要：

为提高热泵热水器的效率，扩大CO2跨临界循环的应用领域，建立了CO2热泵热水器实验系统．实验结果表明：该系统在不同季节工况下均可正常运行，且均能制取出较高温度的热水，但在夏季工况运行时的性能系数和水流量均最高；从健康角度考虑，当该系统运行于夏季工况，且出水温度达到65℃时，性能系数在3．45以上；若系统冷量同时被利用（即空调热水两用机），其综合性能系数可达5．9．可见，CO2热泵热水器在制取热水方面具有独特的优势，从能量利用角度分析，CO2空调热水器两用机在夏季运行时有很好的经济性．

英文摘要：

To expand the application field of CO2 transcritical cycle and enhance the efficiency of heat pump water heater, a CO2 heat pump water heater test system was built. The results show that this test system can nm on different seasons＇ working conditions and get high-temperature hot water, with the highest coefficient of performance （COP） and water flux in stammer; inview of health, in summer when the output water temperature reaches 65 ℃, the COP is above 3.45 ; as the cooling capacity is used at the same time, the total COP of this test system reaches 5.9. It is concluded that the CO2 heat pump water heater has unique advantage for hot water and amphibious machine with air conditioner（AC） and heating water has better economical energy usage in summer.