Thermal performance of an active single basin solar still (ASBS) coupled to shallow solar pond (SSP)

In order to enhance the productivity of single basin solar stills especially during the night, a shallow solar pond (SSP) was coupled to the still. An analytical model for the various elements of the system (the pond and the still) was performed. Numerical calculations were carried out under Tanta prevailing weather conditions. The daily productivities of the active single basin solar still (ASBS) were found to be 5.740 and 1.830 (kg/m(2) day) with and without the SSP, respectively. The daily productivity P-d and efficiency eta(d) of the active still were found to decrease with increasing the thickness d(w) and mass flow rate <(m)over dot> of the water flowing over the basin liner of the still up to typical values of 0.030 m and 0.015 kg/s. Moreover, the monthly average of the daily productivity (P) over bar (d) had minimum values of 3.0 and 1.570 (kg/m(2) day) in December with and without the SSP, respectively. The maximum values of (P) over bar (d) were found to be 6.68 and 5.29 (kg/m(2) day) in July with and without the SSP, respectively. To validate the proposed mathematical models, comparisons between experimental and theoretical results had been performed. Good agreement had been achieved. (C) 2011 Elsevier B.V. All rights reserved.