Structural Optimization And Simulation Analysis Of The Condenser Of Heat Pump System With R744/R290

In recent years,along with the rapid development of the global economy,the issue of energy has increasingly attracted the attention of various countries.Energy conservation and emission reduction and the promotion of low-carbon HVAC are increasingly the theme of today's society.Heat pump technology is an energy-efficient technology.Technology has been widely used.With the advancement of society,heat pump water heaters have gradually entered the field of vision.Generally speaking,the characteristics of the refrigerant and the heat transfer effect of the condenser directly affect the effect of the heat pump water heater.The spiral casing condenser has a secondary flow.The reason is that it has a good heat transfer effect,and it is of great significance to study the condensation heat transfer of the spiral casing condenser.In this paper,the spiral casing condenser of R744/R290 heat pump water heater was optimized and a steady-state distribution parameter model was established,and the heat transfer performance of the combined spiral casing condenser was analyzed.In order to analyze the heat transfer performance of the spiral casing condenser in detail,this paper establishes a simulation study on the spiral casing condenser of the direct heating type R744/R290 heat pump system.The main research work is:(1)Based on the phenomenon that the heat exchange mismatch on the condenser side was found in the previous experimental station,the structural analysis and selection of the condenser were carried out,and the selected spiral casing condenser was optimized.The results show that the performance of the combined spiral casing condenser is the best.The best combination is the refrigerant in the supercooling zone.The structural size is ?16*1mm for the outer pipe and ?10*0.8mm for the inner pipe.The length is 4m;the two-phase and overheating zone take the refrigerant outside the water,the structural size is ?15*1mm,the inner pipe is ?9.52*0.8mm,and the pipe length is 13.32 m.(2)The steady-state distribution parameter model of the casing condenser was constructed,and its reliability was verified by experimental data.The results show that the model can reflect the heat transfer performance of the condenser well,the heat transfer error is within ±7.7%,the water flow error is within ±7.1% and the error of the refrigerant outlet temperature is Within ±1.93 °C,the model has good accuracy.Based on this,a steady-state distributed parameter model is established for the combined spiral casing condenser of R744/R290 heat pump system.(3)Using the established simulation model,the effects of various structural parameters and operating parameters of the combined spiral casing condenser on the heat transfer performance of the condenser were analyzed.Compared with the original casing,the new combined condenser has higher heat exchange efficiency and better heat exchange matching,and the pipe length is shortened by 22% compared with the original casing heat exchanger.