Adsorption kinetics of zeolite coatings directly crystallized on metal supports for heat pump applications (adsorption kinetics of zeolite coatings)

A series of theoretical studies had previously indicated that the utilization of zeolite coatings directly crystallized on metal surfaces might improve the performance of adsorption heat pumps significantly. In this study, for the first time, kinetic measurements were performed to determine the rate of adsorption of zeolite coatings, which is the relevant parameter for increasing the power density of heat pump applications. The zeolite coatings investigated were prepared by using the substrate heating method. A scale-up of the substrate heating system was made in order to be able to grow zeolite coatings on 5 x 5 cm(2) stainless steel plates, instead of the 1 x 1 cm(2) plates, conventionally used in synthesis experiments. Two different reactors were constructed in which zeolite A and X coatings, with mass equivalent thicknesses of about 38 mu m and 230 mu m, respectively, could be obtained. The zeolite X coating, which had a quite open nature, exhibited quite favorable overall adsorption kinetics when compared to a reference sample, a paper-like polymer structure containing zeolite laminated on a metal layer.