NY-14-C060 -- Aerogel-Coated Metal Foams for Dehumidification Applications PDF

Dehumidification is an important feature of HVAC systems because of its thermal-comfort and energy-efficiency implications. Silica aerogels are deployed as solid desiccants in many dehumidification devices, such as enthalpy wheels, due to their superior adsorption and desorption characteristics compared to other desiccant materials. Metal foams are novel materials with a complex repetitive structure and high surface-area-to-volume ratio, which results in better thermal performance relative to existing compact fins. In this paper, a study is conducted on the use of metal foams as substrates for silica aerogels. Silica aerogels are prepared by the Sol-Gel process, coated on metal foams by a dip coating technique and dried under super-critical conditions. Mass diffusion coefficients for silica-aerogel coated metal foams are determined by Dynamic Vapor Sorption (DVS) experiments. An analytical model is developed for the desiccant-coated metal foam for simultaneous heat and mass transfer, including metal foam and desiccant characteristics. The model is used to predict the dehumidification performance of desiccant coated metal foams.