A solar-powered adsorption cooling system using a silica gel–water mixture

Solar-powered adsorption cooling is an attractive solar energy application. Metallic solar collectors with fins have been used to increase the thermal conductivity in solar collectors. This approach has a negative effect due to solar energy loss by reflection and heat loss resulting from the sensible heat of the metal. For these reasons, a direct-radiation absorption collector is proposed here. The effects of the wavelength of the absorbed light, types of silica gel used and additives to improve the absorptivity have been investigated. We have verified that blue silica gel has a better absorptivity in the near-infrared region than white silica gel. The addition of activated carbon to the silica gel improves the desorption rate and regeneration temperature of the packed bed.