Modeling and testing of a dew collection system

In this paper a renewable method of obtaining fresh water from the atmospheric air in the form of dew is proposed. This study deals with the dew formation on radiatively cooled pigmented polyethylene foils. Since a large number of variables are involved in the formation of dew, a steady-state mathematical model is formulated using the energy balance equations and the computer program is developed using the iterative procedure to find the mass rate of condensation of dew from the atmospheric air. Experiments are conducted in Dhahran, Saudi Arabia, with 1 m × 1 m dew collecting panel and about 0.22 L/m2 of water is collected during a single night of operation. Further, the model predictions are compared against the experimental results, with very good agreement. It is found that for maximum possible dew collection, a clear sky with a high degree of atmospheric humidity is needed. The effects of relative humidity of air, the ambient temperature, and the wind speed on the dew collection rate are studied and the results are presented in this paper.