A fully coupled, transient double-diffusive convective model for salt-gradient solar ponds

0017-9310/$ see front matter 2010 Elsevier Ltd. A doi:10.1016/j.ijheatmasstransfer.2010.01.017 * Corresponding author. Tel.: +1 775 784 4986; fax E-mail addresses: [email protected] (F. Su Tyler), [email protected] (A.E. Childress). A fully coupled two-dimensional, numerical model that evaluates, for the first time, the effects of doublediffusive convection in the thermal performance and stability of a salt-gradient solar pond is presented. The inclusion of circulation in the upper and lower convective zone clearly shows that erosion of the nonconvective zone occurs. Model results show that in a two-week period, the temperature in the bottom of the solar pond increased from 20 C to approximately 52 C and, even though the insulating layer is being eroded by double-diffusive convection, the solar pond remained stable. Results from previous models that neglect the effect of double-diffusive convection are shown to over-estimate the temperatures in the bottom of the solar pond. Incorporation of convective mixing is shown to have profound impacts on the overall stability of a solar pond, and demonstrates the need to actively manage the mixing and heat transfer to maintain stability and an insulating non-convective zone. 2010 Elsevier Ltd. All rights reserved.