Energy improvement and performance prediction of desiccant coated dehumidifiers based on dimensional and scaling analysis

Abstract

The evolution of an in-depth understanding and accurate prediction of the dehumidification performance of a solid desiccant coated heat exchanger dehumidifier (SDHED) is severely limited by the unbalanced and unidentified relationships between the product air's thermal conditions and the combined effect of the geometrical parameters under varying operating conditions. Therefore, this paper employs dimensional and scaling analysis (DASA) to unravel the key underlying relationships, leading to improved prediction and optimization of the SDHED’s performance. Firstly, a theoretical model is developed based on the fundamental principles and experimentally validated by employing a SDHED system prototype. Secondly, a DASA is conducted to identify key dimensionless parameters. Two dimensionless variables, δd/δf and β, are found to significantly impact the product air’s properties. Thirdly, new correlations are established to predict the dehumidifier’s outlet humidity and temperature with R2 = 0.965. The results also indicate that the design parameters, H/L and δd/δf, have significant effects on both latent effectiveness and removed latent energy performance of the SDHED. The removed latent energy can be enhanced from 3.9 kW to 8.5 kW when δd/δf and H/L are reduced to 0.1 and 0.04, respectively. In sum, the developed correlations and model present themselves as invaluable tools to facilitate improved design and engineering of SDHED systems.