| Title |
Effects of Tube Diameter and Surface Sub-Cooling Temperature on R1234ze(E) and R1233zd(E) Film Condensation Heat Transfer Characteristics in Smooth Horizontal Laboratory Tubes |
| Authors |
Dong-Soon Jeon ; Ji-Woon Ko ; Seon-Chang Kim |
| DOI |
https://dx.doi.org/10.6110/KJACR.2017.29.5.231 |
| Keywords |
막응축 열전달계수 ; 수평 평활관 ; R1234ze(E) ; R1233zd(E) ; 표면 과냉도 ; 관직경 Film condensation heat transfer coefficient ; Horizontal smooth tube ; R1234ze(E) ; R1233zd(E) ; Surface subcooling temperature ; Tube diameter |
| Abstract |
HFO refrigerants have recently come to be regarded as promising alternatives to R134a for use in turbo chillers. This study provides results from experiments evaluating the film condensation heat transfer characteristics of HFO refrigerants R1234ze(E) and R1233zd(E) on smooth horizontal laboratory tubes. The experiments were conducted at a saturation vapor temperature of 38.0℃ with surface sub-cooling temperatures in the range of 3~15℃. We observe that the film condensation heat transfer coefficient decreases as surface sub-cooling temperatures increase. In the case of laboratory tubes with a diameter of 19.05 mm, the film condensation heat transfer coefficients of R1234ze(E) and R1233zd(E) were approximately 11% and 20% lower than those of R134a, respectively. Furthermore, our investigation of the effect of tube diameter on film condensation heat transfer coefficients, demonstrates an inverse relationship where the film condensation heat transfer coefficient increases as laboratory tube diameter decreases. We propose experimental correlations of Nusselt number for R1234ze(E) and R1233zd(E), which yield a ±20% error band. |