Effect of turbidity on choice of zonal thicknesses in solar ponds under various performance evaluation criteria

Abstract

A turbid solar pond is investigated to study how turbidity in the insulating zone affects the optimum dimensions of the pond, that suit a concerned design criterion. Four different criteria for the optimization have been undertaken, namely: minimizing the maturation time period, maximizing the extraction power under no constraint, maximizing the extraction power under constraint of fixed pond volume and maximizing the extraction power while simultaneously minimizing the volume. Transient numerical solution is sought for the first criterion, whereas for remaining three, a steady-state analytical model is employed that assesses the year-round extraction performance. Simplified versions of the respective models have been validated with data obtained experimentally and with theoretical data available in the literature. It is revealed that turbidity in the salinity gradient zone can lead to considerable alterations in the optimal pond dimensions, regardless of what the criterion used for optimization. The maximum errors in the optimal insulating zone and heat storage zone thickness values, arising from neglect of turbidity are observed to be about 125% and 60%, respectively. Hence, either attempts should be made to make solar ponds free of any foreign agents that cause turbidity, or if not, then they should be designed considering this factor into account, for which this work can serve as a guiding study.