Numerical Modeling and Analysis of the Performance of a Stepped Solar Still using Multi-phase Method

The modeling of solar stills using CFD is a quick and low-cost way of designing and optimizing these systems. So far, only basin-type solar stills have been numerically analyzed; and it is the first time that a 3-D stepped solar still model has been numerically analyzed in the present work. A 3-D and 3-phase numerical model of a stepped solar still is presented in this research. The exterior of this solar still is exposed to ambient temperature and pressure. The initial conditions and temperatures of the system have been determined by an experimental test. The validation results of the present numerical model have a good agreement with former empirical results. The amount of error between numerical and empirical results varies at different times of the day. At early hours, the difference between the water temperatures obtained by modeling and by experimentation is only 1.6%, which rises to 11.7% at later hours of the day. This amount of discrepancy is due to the change that occurs in the behavior of solar still under ambient conditions.