On the Polymer Thickener for Viscosity-Stabilized Solar Pond

The optimal physical properties of an ionized polyacrylamide solution, selected as the most suitable thickener for the insulating layer of a viscosity-stabilized solar pond, are described. Light transmittance, viscosity and viscosity degradation were obtained for a range of thicknesses from 1 cm to 15 cm (1–15 cm), weight concentrations of 0.1–0.5% (0.1–0.5 wt%) and temperatures of the polymer of 20–80°C. Onset of co nvection was also measured for a given thickness of the polymer solution. An exposure test was carried out to prevent degradation of the polymer using an antioxidant. It was confirmed that the viscosity was not decreased and, on the contrary, increased slightly after 100 days. It was shown experimentally that the critical Rayleigh number coincided with the theoretical values reported by Tien et al.. [Int. J. Heat Mass Transf. 12 (1969) 1173]. Transmittances of the polymeric gel for the case of vessels greater than 5 cm in thicknesses were better than those of the SPR402 solution (0.5 wt%).