This paper presents the analysis of two-dimensional heat transfer in an annular finned tube assembly during the process of dehumidification. All possible fin surface conditions, namely, dry, fully wet, and partially wet, have been studied and fin efficiency under these conditions have been modeled. Computations have been carried out using a control volume-based finite-difference method and compared with past one-dimensional analytical studies and available experimental data. The parameters that influenced the heat transfer rate in the finned tube structure are ratio of fin and wall thermal conductivities, ratio of fin thickness to fin pitch, ratio of wall thickness to fin pitch, ratio of fin length to fin pitch, cold fiuid Biot number, ambient Blot number, the relative humidity and dry bulb temperature of the incoming air, and the cold fluid temperature inside the coil. It was found that the heat transfer increased with increment in both dry bulb temperature and the relative humidity of the air. The fin efficiency changed rapidly with relative humidity under partially wet condition. The results suggest that coil performance can be very significantly altered by the condensation phenomenon on the fin surface and designs with dry fin data may not be adequate. The present results are expected to be very useful for the design of dehumidifier (cooling) coils for air conditioning applications.

1.
ASHRAE, 1997, Handbook of Fundamentals, Atlanta, GA.
2.
Chen
L. T.
,
1991
, “
Two-Dimensional Fin Efficiency with Combined Heat and Mass Transfer between Water-Wetted Fin Surface and Moving Moist Airstream
,”
International Journal of Heat and Fluid Flow
, Vol.
12
, No.
1
, pp.
71
76
.
3.
Coney
J. E.
,
Kazeminejad
H.
, and
Sheppard
C. G. W.
,
1989
a, “
Dehumidification of Air on a Vertical Rectangular Fin: A Numerical Study
,”
Journal of Mechanical Engineering Science
, Vol.
203
, pp.
165
175
.
4.
Coney
J. E.
,
Kazeminejad
H.
, and
Sheppard
C. G. W.
,
1989
b, “
Dehumidification of Turbulent Air Flow over a Thick Fin: An Experimental Study
,”
Journal of Mechanical Engineering Science
, Vol.
203
, pp.
177
188
.
5.
Kays, W. M., and London, A. L., 1964, Compact Heat Exchangers, McGraw-Hill, New York, NY.
6.
Kazeminejad
H.
,
1995
, “
Analysis of One-Dimensional Fin Assembly Heat Transfer with Dehumidification
,”
International Journal of Heat and Mass Transfer
, Vol.
38
, No.
3
, pp.
455
462
.
7.
Kern, D. Q., and Kraus, A. D., 1972, Extended Surface Heat Transfer, McGraw-Hill, New York, NY.
8.
Kraus, A. D., 1982, Analysis and Evaluation of Extended Surface Thermal Systems, McGraw-Hill, New York, NY.
9.
Hong
T. K.
, and
Webb
R. L.
,
1996
, “
Calculation of Fin Efficiency for Wet and Dry Fins
,”
International Journal of HVAC and R Research
, Vol.
2
, No.
1
, pp.
27
41
.
10.
McQuiston
F. C.
,
1975
, “
Fin Efficiency with Combined Heat and Mass Transfer
,”
ASHRAE Transactions
, Part 1, Vol.
81
, pp.
350
355
.
11.
McQuiston, F. C., and Parker, J. D., 1994, Heating, Ventilating, and Air Conditioning, 4th Edition, John Wiley & Sons, New York, NY.
12.
Rosario
L.
, and
Rahman
M. M.
,
1998
a, “
Overall Efficiency of a Radial Fin Assembly Under Dehumidification Conditions
,”
ASME JOURNAL OF ENERGY RESOURCES TECHNOLOGY
, Vol.
120
, pp.
299
304
.
13.
Rosario, L., and Rahman, M. M., 1998b, “Modeling of Partially Wet Radial Fin Assembly Used as a Dehumidifier Coil,” Proceedings, 33rd Intersociery Energy Conversion Engineering Conference, CD-Rom, American Nuclear Society. LaGrange Park, IL.
14.
Threlkeld, J. L., 1970, Thermal Environmental Engineering, Prentice-Hall, Englewood Cliffs, NJ.
15.
Schmidt
T. E.
,
1949
, “
Heat Transfer Calculations for Extended Surfaces
,”
Refrigerating Engineering
, Vol.
49
, pp.
351
357
.
16.
Wang
C.
,
Hsieh
Y.
, and
Lin
Y.
,
1997
, “
Performance of Plate Finned Tube Heat Exchangers Under Dehumidifying Conditions
,”
ASME Journal of Heat Transfer
, Vol.
119
, pp.
109
117
.
17.
Webb, R. L., 1994, Principles of Enhanced Heat Transfer, John Wiley & Sons, New York, NY.
18.
Wu
G.
, and
Bong
T. Y.
,
1994
, “
Overall Efficiency of a Straight Fin with Combined Heat and Mass Transfer
,”
ASHRAE Transactions
, Part 1, Vol.
100
, pp.
367
374
.
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