The present research situation of CO2 heat pumps at home and abroad is reviewed

and the important problems in its application process are summarized in the paper. The characteristics and drawbacks of the components and systems

such as the compressor

heat exchanger

and throttle device

are introduced in detail. The latest technological means to improve the efficiency of the system are analyzed

and its development in China is forecasted. The primary reasons for restricting promotion of the CO2 heat pump is high development cost

strict processing technology

and immature

costly

dedicated compression technology. The main research content of the CO2 heat pump in the future is to improve the system

optimize the components

and to combine accurate computer control technology with the achievement of the simultaneous development of hardware and software

so that CO2 heat pump will be operated efficiently

safely

and reliably. It can be predicted that the CO2 heat pump will have promising development in China.