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This article presents an experimental investigation on condensation heat transfer of R-134a in horizontal straight and helically coiled tube-in-tube heat exchangers. The experiments were carried out at three saturation temperatures(35 ℃ , 40 ℃ and 45 ℃ ) with the refrigerant mass flux varying from 100 kg/m2 s to 400 kg/m2 s and the vapor quality ranging from 0.1 to 0.8. The effects of vapor quality and mass flux of R-134a on the condensation heat transfer coefficient were investigated. The results indicate that the condensation heat transfer coefficients of the helical section are 4%-13.8% higher than that of the straight section. The experimental results were compared with the data available in literature for helical and straight pipes.
This article presents an experimental investigation on condensation heat transfer of R-134a in horizontal straight and helically coiled tube-in-tube heat exchangers. The experiments were carried out at three saturation temperatures (35 ° C, 40 ° C and 45 ° C) with the refrigerant The effects of vapor quality and mass flux of R-134a on the condensation heat transfer coefficient were investigated. The results of that that the condensation heat transfer coefficients of the helical sections are 4% -13.8% higher than that of the straight section. The experimental results were compared with the data available in literature for helical and straight pipes.