Abstract: Through the thermodynamic analysis of R290 refrigerant, conclude that the pressure drop should be decreased in the design of R290 outdoor heat exchanger. Through theoretical analysis, obtained in the same process, the φ5 heat exchanger pressure drop is the φ7 heat exchanger 4 times, should be increased the numbers of flow path to reduce the pressure drop. EVAP-COND process simulation software is used to verify and optimize the numbers of flow path. Finally, the experimental results show that the ratio of heat capacity to cold capacity is achieved 1.1 times in the 2HP cooling and heating system within the limited range of R290 refrigerant charge.

Key words: EVAP-COND, Flow path of heat exchanger, Flow path arrangement, R290, Φ5 tubes heat exchanger, Ratio of heat capacity to cold capacity