Synthesis and characterization of silica gel composite with polymer binders for adsorption cooling applications

Abstract

The motivation of the present paper is to synthesis high packing density and thermal conductivity consolidated composite using silica gel powder (SGP) almost without affecting its porous properties. The effect of packing density, binder type and amount on porous properties as well as thermal conductivity were studied. Four types of binder, namely Hydroxyethyl cellulose (HEC), Polyvinyl alcohol (PVA), Polyvinyl pyrrolidone (PVP) and gelatin were chosen. SGP composite with PVP 2 wt% as binder showed better performance for both porous and thermal properties. Thermal conductivity for PVP 2 wt% composite was found 32% higher than SGP. Adsorption uptake of water onto SGP and PVP 2 wt% composite at 30–70 °C adsorption temperatures were measured using gravimetric method. Tóth equation is found suitable to fit the isotherm data. Results showed that there is no change in water adsorption uptake between SGP and PVP 2 wt% composite whereas the volumetric uptake increased by 12.5% for the composite. The studied composites were found to be suitable for designing high performance adsorption cooling systems.