Parametric Evaluation of Condensate Water Yield from Plain Finned Tube Heat Exchangers in Atmospheric Water Generation

This article presents the moisture harvesting capability of plain finned tube heat exchangers, used in active atmospheric water generation systems. The study reviews the data and correlations of heat transfer for such heat exchangers in open literature and embed suitable correlations for predicting the yield of water when exposed to humid air. Set of results are obtained at the inlet and exit of an experimental setup at varying inlet conditions at constant air flowrate and heat exchanger geometry. The heat exchanger is analyzed using a characteristic unit cell where computational fluid dynamics is used to predict temperature drop across it, using COMSOL Multiphysics, whereas the repetitive incremental routines have been carried out using MATLAB. The flowchart is verified by the experimental data. The water product as a result of cooling of the heat exchanger, often considered parasitic for effectiveness of the heat exchanger in sensible cooling applications, is given prime importance, which increases the heat exchanger's water harvesting capability. Psychrometric conditions at the inlet under an interval of dry bulb temperature of 20-40 degrees C and relative humidity of 20-70%, with rows ranging 1 through 4, fin density of 8, 10, 12 and 14 fins per inch and forced convection corresponding to 100 through 2000 cfm, have been analyzed. The results are specified as plots of various variables against the yield of water on a per unit frontal area basis. The increase in water yield is, respectively, highest and lowest for increasing number of rows and increasing fin density.