Zeolite coated copper foams for heat pumping applications

The preparation of a metal supported in situ grown adsorbent bed for adsorption heat pump applications is discussed. The active phase, the zeolite 4A, was directly grown by hydrothermal synthesis on a on-purpose prepared, open-cell, copper foam. The metal foam was obtained by foaming a mixture of epoxy resin, copper powder and a foaming agent in a microwave oven. Subsequently, the metal/polymer foamed composite was heated up to burn the resin matrix and to sinter the metal powder. The so prepared copper foam was preliminary seeded and then exposed to a low temperature (368 K) hydrothermal synthesis in a reactor flask. The accretion treatment was repeated again and an extensive multilayer zeolite 4A coating covering the copper foam surface was obtained. The coating was characterized by SEM, XRD analysis and water adsorption measurements by a Cahn thermobalance. The results in terms of zeolite water uptake in the range of temperatures (328–493 K) and pressures (10–65 mbar) tested, demonstrated a promising performance of the zeolite/foam composite.