Adsorption properties of several materials for solar adsorption cooling system

Abstract

Paper presented to the 10th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Florida, 14-16 July 2014.

It is important for an adsorption refrigeration system to use an appropriate adsorption material and the matched refrigerant. In the present study, the adsorption characteristic of the allochroic silica gel and three kinds of zeolite material to water-vapor have been investigated experimentally. Upon analyzing the variation of the material adsorption capacity exposed in moist air atmosphere of controlled temperature and humidity, the adsorption characteristic to water-vapor is verified, and the influence of the temperature and the pressure are correlated. The results show that the dynamic adsorption characteristic and the adsorption isotherm of the tested material is closely related to its microstructure such as the BET surface area, the distribution of the pore diameter, the porosity, and the bulk density, etc. In view of the application in the solar adsorption air conditioning, 5A-II and 13X-II zeolite shows relatively fast adsorption rate and their time to adsorption saturation state is short. The allochroic silica gel, 5A-II and 13X-II zeolite is of higher adsorption capacity, while the dynamic adsorption characteristic of 5A-I and ZSM-5 zeolite is more sensitive to the change of pressure. The adsorption isotherm of allochroic silica gel follows an exponential function and ZSM-5 and 5A-I zeolites shows a “S" curve, The latter may be more suitable for the solar adsorption cooling system in summer.