Numerical and Experimental Analysis on the Water Harvester using Peltier Effect

Abstract

Condensation of water vapor from humid air is a promising technique to produce water for drinking, cleaning, and other purposes. Several techniques can be used to cool hot and humid air and obtain water from it. For this purpose, Water Harvester is proposed in this study. The process of humid air condensation in this study depends on the performance of experimental and numerical analyses of the fluid flow and condensation performance. The experimental was performed in different operation conditions of working time, air temperature, and relative humidity. The condensation starts and sustains as the surface temperature maintains less than the dew-point temperature. As the relative humidity (RH) of air increased, the amount of condensed water also increased. There is a proportional relation between the condensation rates and the temperature difference. There is also a proportional relation between the cooling surface and air temperatures. It was found that the amount of heat rejected by the system increased as the condensation rate increased. As more heat was rejected, more water vapor was cooled and converted to water. Numerical predictions of the mass fraction of water and air on the cooling surface and condensation rate were performed. Before conducting these analyses, a 3D model of a condensation system to obtain water vapor from humid air through a thermoelectric cooler was built using SolidWorks software and then tested with ANSYS software. The obtained results of numerical analyses showed that the maximum value of the water fraction over the surface was measured as 98.7%, which indicates that 98.7% of the surface was wet. However, the maximum mass fraction of air was measured as only 1.4%. The Sherwood and Reynolds numbers are linearly related; as one increases, so does the other. Good agreement among the two analytical methods was observed during a comparison. Moreover, there was also good agreement between these results and those found in a literature review.