This study is concerned with computer modeling of flow and thermal analysis of solar ponds with a salinity gradient. Solar ponds have been used as an efficient and environmentally friendly approach for collection of solar energy for low temperature thermal applications. A two-dimensional unsteady computational fluid dynamic (CFD) model was developed and used for numerical study of stability analysis of the pond, as well as heat and mass transfer in the salt gradient solar ponds. Salinity gradient was created in order to stabilize the pond and to restrict convective motions induced by buoyancy driven solar radiation heating during the period of operation.
Fluent® commercial software was enhanced with the implementation of User Defined Functions (UDF) and was used in these simulations. The user defined scalar model was included for analyzing the convection and diffusion of the salt concentration in the solar pond. In addition, user defined functions were developed for relating the water density to temperature and salt concentration, as well as, the amount of solar radiation absorption in the solar pond as functions of thermo-physical properties. In the absence of flow exchange, the natural convection in the pond was simulated and the stability of the pond was verified. Development of salt concentration was also studied, and time evolution of temperature distribution in a small scale salinity gradient solar pond was analyzed. For the case of flow exchange at the bottom of the pond, the energy production was evaluated, and the temperature, concentration and flow field were simulated.