Numerical investigation on effect of silica nanoparticles on the middle layer of salt gradient solar ponds

Solar pond is the one of the important ways for collecting and storing solar energy in the world. The salinity gradient solar ponds included the three layers of water-salt with different densities. In this study, the effect of the silica nanoparticles in the middle layer of the salt gradient solar pond was investigated for four different solar radiation zones in Iran. The nanoparticles volume concentrations, which were used in this study, were 1, 2, 5 and 10%. The results showed that nanoparticles improved solar pond efficiency and it increased with nanoparticles concentration. The temperature of the lower layer and efficiency of solar pond increased by 10% and 18 %, respectively. The nanoparticles were more efficient at cold zone.