Modelling and performance analysis of a regenerative solar desalination unit

In this paper, a regenerative solar desalination unit is modeled and its performance evaluated. The unit consists of two basins (effects), with provision for cooling water to flow in and out of the second effect. This arrangement has the advantages of increasing the temperature difference between water and glass cover in the first effect and utilizes the latent heat of water vapor condensing on the glass of the first effect to produce more fresh water in the second effect. The performance of the regenerative still is evaluated by comparison with the performance of the conventional still under the same weather conditions. The results of the simulations show that the productivity of the regenerative still is 20% higher compared to the conventional still. Making the stills perfectly insulated increases their productivity two and one half folds. Insulation has higher effect on the regenerative still compared to the conventional still. The wind speed has a significant effect on the productivity of the stills; it can increase the productivity by more than 50% if the wind speed is increased from 0 to 10 m/s. The thickness of water on top of the first glass cover and the mass flow rate of water going into the second effect have marginal effect on the productivity of the regenerative still.