Study of boundaries equilibrium in a shallow solar pond

Abstract. One-dimensional mass and heat transfer models have been provided to find salinity and temperature gradients in a gradient layer of a solar pond. Using finite difference method (FDM), heat and mass transfer differential equations were discretized by Crank-Nicolson scheme. The present study is based on the experimental data of a solar pond in Ferdowsi University of Mashhad, obtained in a period of 126 days from May to September 1999. Increase in concentration and temperature gradient, cause increase and decrease in stability, respectively. Time variations of concentration and temperature gradients are affect the dynamic stability and equilibrium of upper and lower boundaries of the solar pond. The equilibrium of the upper and lower boundaries has been compared using Neilson equilibrium boundary criterion. The numerical data of the lower boundary were far from dynamic instability. Those data had good agreement with the Neilson equilibrium boundary criterion. The dynamic stability of the upper boundary was maintained with time, but the numerical data of the upper boundary were not in keeping with the Neilson equilibrium boundary criterion. Therefore the lower boundary has with time, behaved with more equilibrium towards the upper boundary.

Keywords:

Boundary equilibrium, Heat and mass transfer, solar pond Stability,

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Weinberger, H. ( 1964), “ The physics Of the solar pond”, solar Energy, 8 (2), pp. 45-56
Meyer, K.A. (1983), “Numerical model for describing the layer behavior in salt-gradient solar pond”, Journal of Solar Energy Engineering, 105(4), pp. 341-34
Jaefarzadeh, M.R. (2000), “On the performance of a salt gradient solar pond”, Applied Thermal Engineering 20(3), pp. 243–252
Bezir, N.C., Ozek, N., Kayali, R., Yakut, A.K., Sencan, A., and Kalogirou, S., "Theoretical and experimental Analysis of salt gradient solar pond with insulated and reflective covers", Energy Sources, Part A, 31:985-1003, 2009.
Mansour, R.B., Nguyen, C. T., and Galanis, N., "Numerical study of transient heat and mass transfer and stability in a salt-gradient solar pond", Int. J. Thermal Sciences 43, pp. 779-790, 2004.
Busquets,E., Kumar,V., Motta,J., Chacon,R. and Lu,H. "Thermal analysis and measurement of a solar pond prototype to study the non-convective zone salt gradient stability", Solar Energy, Volume 86, Issue 5, May 2012, Pages 1366-1377
Giestas,M.,Pina,H.,Joyce,A.”The influence of radiation absorption on solar pond stability ”,J. Heat and mass transfer 39(18)(1996)3873-3885
Giestas, M., Joyce, A., Pina,H., " The influence of nonconstant diffusivities on solar ponds stability ", Int. J. Heat and Mass Transfer 18, pp. 4379-4391, 1997.
Kaufmann, D.W., " Sodium Chloride. Reinhold ", New York , 1960.
Nielsen ,C.E. ,"Control of gradient zone boundaries" , in: Proceedings of the Int. Solar Energy Society, Atlanta, pp. 1010-1014, 1979.
Rahimpour, M., "Study of gradient layer thickness in solar ponds”, M. S. thesis, School of Engineering, Ferdowsi University of Mashhad, 1999.(Farsi )