Experimental Investigation on Condensation Heat Transfer of R404A and R407C outside Horizontal Enhanced Tubes

Experimental Investigation on Condensation Heat Transfer of R404A and R407C outside Horizontal Enhanced Tubes

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The condensation heat transfer performance outside horizontal enhanced tubes of near-azeotropic refrigerant R404A and zeotropic refrigerant R407C was investigated in this study.The experimental data were analyzed using Wilson graphical method.The results show that the coefficients of condensation heat transfer outside horizontal enhanced tubes of R404A and R407C increase with the increase of supercooling degree of tube wall, which is different from pure refrigerant.

For near-azeotropic or zeotropic refrigerant, some components will encounter the gas film resistance caused by Baby Bowl the condensation of other components.With the increase of supercooling degree of tube wall, the volatile components begin to condense and the gas film becomes thin, thus the coefficient of condensation heat transfer will increase.The coefficient of condensation heat transfer outside horizontal enhanced tubes of R407C is 70% lower than R404A, which is due to the fact that the temperature glide of R407C is larger than R404A, and the impact of gas film outside tubes Knife is greater.

The heat transfer coefficient of R407C is improved obviously at higer heat flux condition, which is suitable for practical application.