Browse > Article

Effects of Evaporation Water Flow Rate on the Performance of an Indirect Evaporative Cooler  

Choo, Hyun-Seon (Department of Mechanical Engineering, Graduate School, Hanyang University)
Lee, Kwan-Soo (Department of Mechanical Engineering, Hanyang University)
Lee, Dea-Young (Korea Institute of Science & Technology)
Publication Information
Korean Journal of Air-Conditioning and Refrigeration Engineering / v.18, no.9, 2006 , pp. 714-721 More about this Journal
Abstract
In evaporative cooling applications, the evaporation water is supplied usually sufficiently larger than the amount evaporated to enlarge contact surface between the water and the air. Especially in indirect evaporative coolers, however, if the evaporation water flow rate is excessively large, the evaporative cooling effect is not used for heat absorption from the hot fluid but spent to the sensible cooling of the evaporation water itself. This would result in a decrease in the cooling performance of the indirect evaporative cooler. In this study, the effects of the evaporation water flow rate on the cooling performance are investigated theoretically. The cooling process in an indirect evaporative cooler is modeled into a set of linear differential equations and solved to obtain the exact solutions to the temperatures of the hot fluid, the moist air, and the evaporation water. Based on the exact solutions, it is analyzed how much the cooling performance is affected by the evaporation water flow rate. The results show that the decrease in the cooling effectiveness is substantial even for a small flow rate of the evaporation water and the relative decrease is more serious for a high-performance evaporative cooler.
Keywords
Inditect evaporative cooler; Evaporation water flow rate; Evaporation water temperature; Film Reynolds number; Effectiveness;
Citations & Related Records
Times Cited By KSCI : 1  (Citation Analysis)
연도 인용수 순위
1 Yang, W. J., and Clack, D. W., 1975, Spray cooling of air-cooled compact heat exchangers, Int. J, of Heat Mass Transfer, Vol. 18, pp.311-317   DOI   ScienceOn
2 Sweetland, M. and Lienhard, J. H., 2000, Evaporative cooling of continuously drawn glass fibers by water sprays, Int. J. of Heat and Mass Transfer, Vol. 43, pp.777-790   DOI   ScienceOn
3 Lee, D.-Y., Lee, J. W. and Kang, B. H., 2005, An experimental study on the effects of porous layer treatment on evaporative cooling of an inclined surface, Korean Journal of Air-Conditioning and Refrigeration Engineering, Vol. 17, pp.25-32   과학기술학회마을
4 Wang, T. A. and Reid, R. L., 1996, Surface wettablity effect on an indirect evaporative cooling system, ASHRAE Transaction, Vol. 102, No.1, pp.427-433
5 Kettleborough, C. F. and Hsieh, C. S., 1983, The thermal performance of the wet surface plastic plate heat exchanger used as an indirect evaporative cooler, ASME J, Heat Transfer, Vol. 105, pp.366-373   DOI
6 Gou, X. C. and Zhao, T. S., 1998, A parametric study of an indirect evaporation air cooler, Int. Comm. Heat Mass Transfer, Vol. 43, pp.777-790
7 Facao, J. and Oliveira, A. C., 2000, Thermal behavior of closed wet cooling towers for use with chilled ceilings, Applied Thermal Engineering, Vol. 43, pp.777-790
8 Peterson, J. L., 1993, An effectiveness model for indirect evaporative coolers, ASHRAE Trans., Vol. 99, pp.392-399
9 Brown, W. K., 1996, Application of evaporative cooling to large HV AC system, ASHRAE Transaction, Part I, pp. 895-907
10 Cangel, P. A., 2003, Heat Transfer: A Practical Approach, 2nd ed., McGraw-Hill, pp. 128-131, 515-553
11 Maclaine-Cross, I. L. and Banks, P.J., 1981, A general theory of wet surface heat exchangers and its application to regenerative evaporative cooling, ASME J. Heat Transfer, Vol.103, pp.579-585   DOI
12 Incropera, F. P. and DeWitt, D. P., 2002, Fundamentals of Heat and Mass Transfer, John Wiley and Sons, pp. 647-665