The Influence of the Inlet Conditions on the Airside Heat Transfer Performance of Plain Finned Evaporator
A numerical study has been conducted to investigate the influence of fin pitch and relative humidity on the heat transfer performance of the fin-and-tube heat exchangers having plain fin geometry under dehumidifying conditions. The analysis is done using the ratio between the heat transfer coefficients in totally wet conditions and those in totally dry conditions using the appropriate correlations for both dry and wet conditions. For a constant relative humidity, it is found that the heat transfer coefficient increases with the increase of the air frontal velocity. By contrast, the fin efficiency decreases when the face velocity is increased. Apparently, this phenomenon is attributed to the path of condensate drainage. For the influence of relative humidity, the results showed an increase in heat transfer performance and a decrease in wet fin efficiency when relative humidity increases. This is due to the higher amount of mass transfer encountered at higher relative humidity. However, it is found that the effect of fin pitch on the heat transfer performance depends strongly on the face velocity. At lower frontal velocity the heat transfer increases with fin pitch. Conversely, an increase in fin pitch gives lower heat transfer coefficients when air velocity is increased.
Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1085569Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 2000
 A. H. Elmahdy, R.C. Biggs, "Performance simulation of multi-row dry (and/or wet) heat exchangers", Sixth International Heat Transfer Conference, held in Toronto, 7 - 11 August 1978, pp. 327-332.
 D. R. Mirth & S. Ramadhyani, "Prediction of cooling-coil performance under condensing conditions", Int. J. Heat and Fluid Flow, Vol. 14, No. 4, December 1993, pp 391-400.
 A.H. Elmahdy & R.C. Biggs, "Efficiency of Extended Surfaces with Simultaneous Heat and Mass Transfer", ASHRAE Transactions, 1983, pp. 135-143.
 Han-Taw Chen & Hung-Chih Wang, "Estimation of heat transfer characteristics on a fin under wet conditions", International Journal of Heat and Mass Transfer 51, 2008, pp. 2123-2138.
 W. Pirompugd, C. C. Wang, S. Wongwises, "Finite circular fin method for heat and mass transfer characteristics for plain fin-and-tube heat exchangers under fully and partially wet surface conditions", International Journal of Heat and Mass Transfer 50, 2007, pp. 552-565.
 C. C. Wang, Y. T. Lin and C. J. Lee, "An airside correlation for plain finand- tube heat exchangers in wet conditions", International Journal of Heat and Mass Transfer 43, 2000, pp. 1869-1872.
 C. C. Wang, Y. J. Chang, Y. C. Hsieh, Y. T. Lin, "Sensible heat and friction characteristics of plate fin-and-tube heat exchangers having plane fins", Int. J. Refrig. Vol. 19, No. 4, pp. 223- 230, 1996.