VARIATIONS OF TEMPERATURE, CONCENTRATION, AND SUPERSATURATION IN A LABORATORY-SCALE SATURATED SOLAR POND

A laboratory simulation system of a saturated solar pond using alum potash was operated in a series of experiments of 30 to 120 days' duration. The system consisted of an insulated column 100 cm deep, heated at the bottom by heat exchangers with varying energy output. The supersaturation, temperature and concentration in the upper layer as a function of time are presented. Both insufficient and excessive heat flow cause failure of the layered configuration. Suitably adjusted heat flow allows preservation of the layered structure. The concentration of the upper layer and the supersaturation display cyclic character: after attaining high supersaturation massive crystallization occurs with crystals sinking to the bottom where they are dissolved. The upward diffusion from the highly concentrated bottom solution completes the solute cycle and maintains the stability of the pond. © 1990.