为提高跨临界CO2空气源热泵热水系统运行性能，对不同压缩机频率、电子膨胀阀开度和水流量下的系统及部件运行特性进行了实验研究，并对循环加热模式下的调节方式进行了优化。结果表明：当阀开度减小时，系统性能系数COP和制热量随过热度的增大而减小；压缩机存在最大电效率点，并且电效率极值点会随着运行频率的增大而向低过热度段发生移动；与电子膨胀阀调节方式相比，水流量调节方案下系统COP提升了13.22%；在循环加热模式下不同加热时期的最优阀开度并不相同，根据最优高压理论对其调节方式进行了优化，最大优化率为15.96%。

In order to improve the working performance of carbon dioxide transcritical air source heat pump system, the operating characteristics of the system and components under different compressor frequencies, electronic expansion valve (EEV) openings and water flow rates were studied experimentally. The control method under the circulating heating mode was also optimized. The results show that as the valve opening decreases, the system coefficient of performance (COP) and heat production will decrease with the increase of superheat. There is a maximum electrical efficiency point of the compressor, and the maximum electrical efficiency point will transfer to the low superheat section with the increase of operating frequency. Compared with the electronic expansion valve control method, the system COP increases by 13.22% with the water flow control method. Under the circulating heating mode, the optimal valve opening is different in each heating period. The control method is optimized according to the optimal high pressure theory, and the maximum optimization rate is 15.96%.

TK124