Heat Transfer Enhancement in Cool-thermal Discharge Systems from Ice Melting with Producing Chilled Air under Time-velocity Variations and External Recycles

Chii-Dong  Ho; Ho-Ming Yeh; Jr-Wei  Tu; Ying-Sian Su

doi:10.6180/jase.2005.8.4.05

Heat Transfer Enhancement in Cool-thermal Discharge Systems from Ice Melting with Producing Chilled Air under Time-velocity Variations and External Recycles

Chii-Dong Ho This email address is being protected from spambots. You need JavaScript enabled to view it.¹, Ho-Ming Yeh¹, Jr-Wei Tu¹ and Ying-Sian Su¹

¹Department of Chemical and Materials Engineering, Tamkang University Tamsui, Taiwan 251, R.O.C.

Received: March 4, 2005
Accepted: April 27, 2005
Publication Date: December 1, 2005

Download Citation: ||https://doi.org/10.6180/jase.2005.8.4.05

ABSTRACT

A mathematical model of cool-thermal discharge systems with external recycle by melting ice with producing chilled air to supply on-peak daytime air-conditioning needs was developed and studied analytically. The estimation of the outlet chilled air temperature and air mass velocity with convective transfer on free water surface under air time-velocity variations for specified inlet temperatures was illustrated. Theoretical results show that the recycle effect can effectively enhance the heat transfer efficiency compared with that in the device without recycle. Three numerical examples of ambient air temperatures varied with time in practical systems were simulated, and the result of air mass velocity with air traversed length as a parameter was also delineated.

Keywords: Heat Transfer, Cool Thermal Discharge, Chilled Air, External Recycles

REFERENCES

[1] Hasnain, S. M., “Review on Sustainable Thermal Energy Storage Technologies Part I: Cool Thermal Storage,” Energy Convers. Mgmt., Vol. 39, pp. 11391153 (1998).
[2] Yeh, H. M. and Cheng, C. Y., “Cool Thermal Storage by Vacuum Freezing of Water,” Energy, Vol. 16, pp. 10451049 (1991).
[3] Ho, C. D., Yeh, H. M. and Wang, W. P., “Thermal Characteristics of Ice under Constant Heat Flux and Melt Removal,” Heat Transfer Eng., Vol. 23, pp. 36 44 (2002).
[4] Ho, C. D., Yeh, H. M. and Wang, W. P., “Cool Thermal Discharge with Time-velocity of Flowing Air in situ Contact on Water Surface,” J. Chin. Inst. Chem. Engrs., Vol. 29, pp. 249255 (1998).
[5] Siegel, M. H., Merchuk, J. C., and Schugerl, K., “Air-lift Reactor Analysis: Interrelationships Between Riser, Downcomer, and Gas-liquid Separator Behavior, Including Gas Recirculation Effects,” AIChE J., Vol. 32, pp. 15851596 (1986).
[6] Jones, A. G., “Liquid Circulation in a Draft-tube Bubble Column,” Chem. Eng. Sci., Vol. 40, pp. 449462 (1985).
[7] Marquart, R., “Circulation of High-viscosity Newtonian and Non-newtonian Liquids in Jet Loop Reactor,” Int. Chem. Eng., Vol. 20, pp. 399407 (1981).
[8] Ho, C. D., Yeh, H. M. and Su, Y. S., “Improvement in Performance of Cool-thermal Discharge Systems from Ice Melting with Producing Chilled Air Under Constant Heat Flux and External Refluxes,” Numerical Heat Transfer, Part A, Vol. 45, pp. 505516 (2004).
[9] Penner, S. S. and Sherman, S., “Heat Flow Through Composite Cylinders,” J. Chem. Phys., Vol. 15, pp. 569 574 (1947).
[10] Carslaw, H. S. and Jaeger, J. C., “Conduction of Heat in Solids,” 2nd ed., Oxford Univ. Press, New York, NY, U.S.A. (1959).
[11] Eckert, E. R. G. and Drake, R. M. Jr., “Analysis of Heat and Mass Transfer,” McGraw-Hill, New York, NY, U.S.A. (1972).
[12] Mercer, W. E., Pearce, W. M. and Hitchcock, J. E., “Laminar Forced Convection in the Entrance Region Between Parallel Flat Plates,” J. Heat Transfer, Vol. 89, pp. 251257 (1967).
[13] Kays, W. M. and Crawford, M. E., “Convective Heat and Mass Transfer,” McGraw-Hill, New York, NY, U.S.A. (1993).