Wall profile optimisation of a salt gradient solar pond using a generalized model

Abstract

This study carries a generalized model-based constrained analysis to optimise the wall profile of a solar pond. For this analysis, different profiles are studied which include linear, concave parabolic and convex parabolic walls with circular and square cross sections. The present optimisation is particularly aimed at maximizing the efficiency of the pond with reference to a given volume of water and top area. At first, the available literature model is modified to incorporate the variation of the local cross sectional area of the pond. A scaled down and unconstrained version of the present model has been then validated against theoretical and experimental results available in the literature. The constrained optimisation analysis reveals that, each of the profiles converges to the vertical shape towards maximizing the power output. For a fixed volume pond of any geometry, the pond efficiency is driven by a mutual trade-off between the available solar energy, its absorption and energy lost by conduction. It is envisaged that a vertical wall offers more output from the pond than an equal volume pond of any other geometry. The present work provides a direct procedure to assess the performance of solar pond involving any geometry and offers a cost effective alternative to other performance enhancing techniques.