0
Research Papers: Heat Exchangers

The New Mathematical Models for Plain Fin-and-Tube Heat Exchangers With Dehumidification

[+] Author and Article Information
Worachest Pirompugd

Department of Mechanical Engineering,
Faculty of Engineering,
Burapha University,
Saensook, Muang,
Chonburi 20131, Thailand
e-mail: worapiro@gmail.com

Chi-Chuan Wang

Department of Mechanical Engineering,
National Chiao Tung University,
EE474, 1001 University Road,
Hsinchu 300, Taiwan
e-mail: ccwang@mail.nctu.edu.tw

Somchai Wongwises

Fluid Mechanics,
Thermal Engineering and Multiphase
Flow Research Laboratory (FUTURE),
Department of Mechanical Engineering,
Faculty of Engineering,
King Mongkut's
University of Technology Thonburi,
Bangmod, Bangkok 10140, Thailand
e-mail: somchai.won@kmutt.ac.th

Contributed by the Heat Transfer Division of ASME for publication in the JOURNAL OF HEAT TRANSFER. Manuscript received May 29, 2014; final manuscript received October 24, 2014; published online December 2, 2014. Assoc. Editor: Ali Khounsary.

J. Heat Transfer 137(3), 031801 (Mar 01, 2015) (11 pages) Paper No: HT-14-1357; doi: 10.1115/1.4029037 History: Received May 29, 2014; Revised October 24, 2014; Online December 02, 2014

For evaluating performance of fin-and-tube heat exchangers under dehumidifying conditions, the recent lumped approach models are based on the enthalpy potential or equivalent dry bulb temperature. This study proposes a new lumped approach model based on the dry bulb temperature difference. The concept of dry bulb temperature was first presented by McQuiston for derivation of fin efficiency under dehumidifying conditions in 1975. This concept is simpler than the concepts of enthalpy potential and equivalent dry bulb temperature. Nevertheless, it cannot be found that this concept is applied to the fin-and-tube heat exchangers. Moreover, this study also presents the finite circular fin method (FCFM) based on the dry bulb temperature and equivalent dry bulb temperature. The FCFM was first presented in our published literature but it was based on the enthalpy potential. The FCFM is done by dividing the fin-and-tube heat exchanger into many small segments. Then, the segments are divided into three cases: fully dry condition, fully wet condition, and partially wet condition. From the results, the new lumped approach model based on dry bulb temperature gives a good result. It is the simplest method for evaluating heat transfer performance of fin-and-tube heat exchangers under fully wet conditions. For the FCFM, the heat and mass transfer characteristics obtained by dry bulb temperature and equivalent dry bulb temperature are nearly the same as those obtained by the enthalpy potential. However, the heat and mass transfer characteristics by the FCFM based on equivalent dry bulb temperature are higher than those obtained by the FCFM based on dry bulb temperature. This is because of the effect of the nonconstant term in the two methods. The correlations applicable for both fully wet and partially wet conditions for the FCFMs based on equivalent dry bulb temperature and dry bulb temperature are proposed to describe the heat and mass transfer characteristics for the present plain fin configuration.

FIGURES IN THIS ARTICLE
<>
Copyright © 2015 by ASME
Your Session has timed out. Please sign back in to continue.

References

Figures

Grahic Jump Location
Fig. 2

Fin efficiency for a partially wet condition plotted against Mm(ro − ri)

Grahic Jump Location
Fig. 3

di/dT, ζ, and (1 + ξifg/Cp,a) plotted against r for radial fin

Grahic Jump Location
Fig. 1

Comparison of jh between lump approach and FCFM. (a) jh between enthalpy potential and presented dry bulb temperature. (b) jh between lump approach and FCFM.

Grahic Jump Location
Fig. 7

Comparison of predicted data with experimental data. (a) jh by FCFM-EDT, (b) jm by FCFM-EDT, (c) jh by FCFM-DT, and (d) jm by FCFM-DT.

Grahic Jump Location
Fig. 4

Comparison of jh and jm between those obtained by FCFM-DT or FCFM-EDT with FCFM-EP (a) jh obtained by FCFM-EDT versus FCFM-EP, (b) jh obtained by FCFM-DT versus FCFM-EP,(c) jm obtained by FCFM-EDT versus FCFM-EP, and (d) jm obtained by FCFM-DT versus FCFM-EP

Grahic Jump Location
Fig. 5

jh obtained by FCFM-EDT and FCFM-DT. (a) jh for 1 Row with RH = 0.5, (b) jh for 2 Rows with RH = 0.5, (c) jh for 4 Rows with RH = 0.5, (d) jh for 6 Rows with RH = 0.5, (e) jh for 4 Rows with RH = 0.9, and (f) jh for 6 Rows with RH = 0.9.

Grahic Jump Location
Fig. 6

jm obtained by FCFM-EDT and FCFM-DT. (a) jm for 1 Row with RH = 0.5, (b) jm for 2 Rows with RH = 0.5, (c) jm for 4 Rows with RH = 0.5, (d) jm for 6 Rows with RH = 0.5, (e) jm for 4 Rows with RH = 0.9, and (f) jm for 2 Rows with RH = 0.9.

Tables

Errata

Discussions

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In