Characterisation and heat losses from a laboratory salt gradient solar pond

A salt gradient laboratory solar pond made of concrete-cement having dimensions 40 × 40 × 90 cm³ has been used for this experimental study. The pond was initially filled with 15% and 20% brine solution up to one-fourth and one-third height from the bottom of the pond, respectively, and the remaining depth of the pond was filled with fresh water. The density distributions were measured several times at room temperature at intervals of ten days. Having thus obtained the stable salt density gradient, the pond was then heated from the bottom at various fixed temperatures. These fixed temperatures were raised in steps of 5°C. Salinity distribution and temperature distributions along the depth of it were measured for every operating (heating) temperature. Temperature distributions at the outer surface of the walls of the pond were also observed at each (fixed) operating temperature. Dry dune sand has been used as an insulator with different thickness surrounding the walls of the pond. Behaviour of this insulation was studied for a 45°C heating temperature by calculating the heat losses from the walls of the pond.