Performance of Plate Finned Tube Heat Exchangers Under Dehumidifying Conditions

1997 ◽  
Vol 119 (1) ◽  
pp. 109-117 ◽  
Author(s):  
Chi-chuan Wang ◽  
Yi-chung Hsieh ◽  
Yur-tsai Lin
Keyword(s):  
Heat Exchangers ◽  
Finned Tube ◽  
Fin Efficiency ◽  
Friction Factors ◽  
Inlet Conditions ◽  
Fin Spacing

Systematic studies of continuous fin-and-tube tube heat exchangers under dehumidifying conditions are reported in the present study. The heat exchangers consist of nine fin-and-tube heat exchangers having plane fins. The effects of fin spacing, the number of tube row, and inlet conditions are investigated. Data are presented in terms of j factors and friction factors f. It is found that the inconsistencies in the open literature may be associated with the wet fin efficiency. A correlation is proposed for the present plate fin configuration; this correlation can describe 92 percent of j, and 91 percent of the f data within ±10 percent.

Dehumidification: On the Correlation of Wet and Dry Transport Processes in Plate Finned-Tube Heat Exchangers

1987 ◽  
Vol 109 (3) ◽  
pp. 575-582 ◽  
Author(s):  
P. W. Eckels ◽  
T. J. Rabas
Keyword(s):  
Boundary Layer ◽  
Heat Exchangers ◽  
Transverse Velocity ◽  
Density Variation ◽  
Finned Tube ◽  
Transport Processes ◽  
Condensate Film ◽  
Boundary Layer Suction ◽  
Friction Factors ◽  
Dry Transport

The transverse velocity of the condensing phase during dehumidification is analogous to the transverse velocity at the wall when exercising boundary layer control by fluid extraction through a permeable wall. Wet and dry pressure drop and heat transfer rates are analyzed for correlation using boundary layer suction theory. Data are presented for flat-plate finned-tube heat exchangers during air heating and dehumidification operations and the data show a significant effect of transverse velocity correlated by the boundary layer suction formulation. The condensate film is considered isothermal in this analysis and the results indicate that an improved modeling of the condensate film is required. We find that the transverse velocity of the condensing phase has an important effect on transport phenomena during dehumidification and that the validity of the Chilton–Colburn heat and mass transfer analogy in describing dehumidification is supported by these results. It should be noted that the dry data form the beginning of a plate fin heat exchanger data base. The present data show the effect of tube diameter and, independently, fin density variation on the Colburn and friction factors with all other geometric parameters held invariant.

Performance of Dehumidifying Heat Exchangers With and Without Wetting Coatings

1999 ◽  
Vol 121 (4) ◽  
pp. 1018-1026 ◽  
Author(s):  
K. Hong ◽  
R. L. Webb
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Pressure Drop ◽  
Transfer Coefficient ◽  
Heat Exchangers ◽  
Finned Tube ◽  
Fin Efficiency ◽  
Dry Heat ◽  
Reduction Methods ◽  
Wet Surface

Limited previous work has shown that use of special hydrophilic coatings will provide lower air pressure drop in finned tube heat exchangers operated under dehumidifying conditions. However, no detailed work has been reported on the effect of different coating types, or different fin surface geometries on the wet pressure drop. In this study, wind tunnel tests were performed on three different fin geometries (wavy, lanced, and louver) under wet and dry conditions. All dehumidification tests were done for fully wet surface conditions. For each geometry, the tests were performed on uncoated and coated heat exchangers. For all three fin geometries, the wet-to-dry pressure drop ratio was 1.2 at 2.5 m/s frontal air velocity. The coatings have no influence on the wet or dry heat transfer coefficient. However, the wet surface heat transfer coefficient was 10 to 30 percent less than the dry heat transfer coefficient, depending on the particular fin geometry. The effect of the fin press oil on wet pressure drop was also studied. If the oil contains a surfactant, good temporary wetting can be obtained on an uncoated surface; however, this effect is quickly degraded as the oil is washed from the surface during wet operation. This work also provides a critical assessment of data reduction methods for wet surface operation, including calculation of the fin efficiency.

Optimum fin spacing of finned tube adsorber bed heat exchangers in an exhaust gas-driven adsorption cooling system

2018 ◽  
Vol 232 ◽  
pp. 504-516 ◽  
Author(s):  
Behzad Golparvar ◽  
Hamid Niazmand ◽  
Amir Sharafian ◽  
Amirjavad Ahmadian Hosseini
Keyword(s):  
Heat Exchangers ◽  
Cooling System ◽  
Finned Tube ◽  
Exhaust Gas ◽  
Adsorption Cooling System ◽  
Fin Spacing ◽  
Adsorber Bed

Dimensionless Parameters for the Optimization of Annular-Finned Tubes

2000 ◽  
Author(s):  
Cristóbal Cortés ◽  
Inmaculada Arauzo ◽  
Antonio Campo
Keyword(s):  
Heat Exchangers ◽  
Finned Tube ◽  
Thermal Conductivity Ratio ◽  
Finned Tubes ◽  
Standard Designs ◽  
Design Calculations ◽  
Annular Fins ◽  
Fin Spacing ◽  
Independent Parameters ◽  
Dimensionless Formulation

Abstract This paper addresses the problem of optimizing an array of annular fins starting from an empirical fit of the average convection coefficient that recognizes the influence of the fin spacing. A dimensionless formulation is proposed to reduce the number of independent parameters to only four, being applicable to a rather generic situation. The formulation is illustrated with a parametric study encompassing the ranges of interest of the variables: Reynolds number, thermal conductivity ratio, volume constraint and fin spacing and thickness. Applied to the standard designs of annular-finned heat exchangers, the method predicts fully coherent points of optimum thermal performance. A sequence is suggested to integrate the optimization process within the design calculations of heat exchangers, and several graphs are presented which are suitable to this purpose. The method can be applied to the design and scaling calculations of annular-finned tube bundles for gas-liquid or gas-gas applications.

AIR-SIDE PERFORMANCE OF FINNED TUBE HEAT EXCHANGERS UNDER DEHUMIDIFYING CONDITIONS

2019 ◽  
Author(s):  
Jacqueline Copetti ◽  
Mario Henrique Macagnan ◽  
Anselmo Goulart Gonçalves ◽  
Desirê Lara Mehringer Kreische
Keyword(s):  
Heat Exchangers ◽  
Finned Tube
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