Comparative analysis of microfin vs smooth tubes in R32 and R410A condensation. (August 2021)

• Record Type: Journal Article
• Authors: Longo, Giovanni A.; Mancin, Simone; Righetti, Giulia; Zilio, Claudio
• Is Part Of: International journal of refrigeration. Volume 128(2021)
• Page Start: 218
• Page End: 231
• Publication Date: 2021-08
• Subjects: Condensation -- Microfin -- R32 -- R410A -- Smooth -- Small-diameter; Condensation -- Micro-ailettes -- R32 -- R410A -- Lisse -- Faible diamètre; Refrigeration and refrigerating machinery -- Periodicals; 621.56
• DOI: 10.1016/j.ijrefrig.2021.04.011
• Languages: English
• ISSNs: 0140-7007

Abstract

Highlights: This paper investigates R32 and R410A condensation inside a 4.2 mm microfin tube. The microfin tube exhibits a maximum heat transfer enhancement around 3.5−3.6. The optimum mass velocity for the microfin tube is in the range 150−300 kg m −2 s −1 . R32 exhibits heat transfer coefficients and pressure drops higher than R410A. R32 is a very promising low GWP substitute for R410A. Abstract: This study performs the comparative analysis of R32 and R410A condensation inside a 4.2 mm ID microfin tube: the effects of saturation temperature, vapour quality and mass velocities are evaluated. The heat transfer coefficients show a great sensitivity to vapour quality, a non-negligible sensitivity to saturation temperature/pressure, and a non-monotonic trend versus mass velocity. The microfin tube exhibits a maximum heat transfer enhancement with respect to the smooth tube around 3.5−3.6 at a mass velocity of 200 kg m −2 s −1 and a vapour quality of 0.8. The optimum mass velocity for R32 and R410A condensation inside the microfin tube is in the range 150−300 kg m −2 s −1 . R32 exhibits condensation heat transfer coefficients 20 − 30% higher and frictional pressure drops 10 − 20% higher than those of R410A and it seems a valuable low GWP substitute for R410A.