Solar energy storage by salinity gradient solar pond: Pilot plant construction and gradient control

An experimental solar pond pilot plant was constructed in Solvay-Martorell, facilities, Catalonia (NE part of the Iberian Peninsula) to capture and store solar energy. The body of the pond is a cylindrical reinforced concrete tank, 3m height, 8m diameter and total area of 50m 2. Salinity and thermal gradient were properly established by using the salinity distribution methodology. The gradient in the pond was maintained by feeding salt (NaCl) through a cylindrical salt charger to the bottom at a height of 80cm from the pond floor. Continuous surface washing using tap water supply maintained the salinity of the top convective layer at a low level and compensate loses by evaporation.