| As a new environmentally friendly refrigerant,R1234 yf has potential advantages in replacing high-GWP refrigerant R134 a.The heat transfer performance of different refrigerants in heat exchangers varies.Based on theoretical analysis,numerical simulation and experimental research methods,the heat transfer law of refrigerant R1234 yf in casing condenser was analyzed.In order to improve the performance of the heat pump system,a casing type watercooled condenser was designed.The diameter of the refrigerant pipe is 9.52 mm,the pipe diameter of the water pipe is 28 mm,and the heat pipe length is 11 m.The latent heat value of R134 a is slightly higher than that of R1234 yf refrigerant.The heat pump system test bench was set up to change the cooling water flow rate and temperature to obtain the following heat transfer law: as the cooling water inlet water temperature increased,the condenser heating COP values of the R134 a heat pump system and the R1234 yf heat pump system decreased to varying degrees.The heat exchange efficiency is lowered due to an increase in the temperature of the water side of the condenser.Adjust the test point temperature distribution measurement point to obtain the temperature change trend of the condenser along the tube length direction under different flow rates and temperatures.The heat transfer law of heat exchangers with different pipe diameters and pipe lengths was obtained by simulation analysis.The agreement between the simulation and the test was good.Figure41;Table11;Reference 44... |
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