Experimental Investigation of the Helical Condenser for Humidification Dehumidification Desalination Unit Powered by Solar Energy

Abstract

In this paper, built the water desalination unit based on the humidification dehumidification (HDH) process powered by solar energy was examined. The unit uses a humidifier of the packing type (HPT) and the dehumidifier (condenser) made a concentric helically tube and shell heat exchanger was investigated. The dehumidifier was used to condensate water vapor from humid air. The Nusselt number (Nu) inside the helical tube was discussed in many studies before, although it is not mentioned before the Nusselt number outside the helical tube for a mixture fluid. In the current study cold water in passing inside a concentric helical tube, while a hot humid air passing over the external surface of the concentric helical tube. The concentric helical tube is positioned inside an insulated shell. Different air flowrates were used, and the experimental results were used to induce a new empirical equation for the shell’s Nusselt number. The water desalination unit was examined by using the solar collectors as a heating source for the saline feed water and the introduced air to the humidifier, and it is found that the freshwater productivity was 8.60 kg/day and to reduce the carbon dioxide released by 4600 g/day.