MORPHOLOGICAL ANALYSIS OF VAPOR ADSORBENT ZEOLITE COMPOSITE FOAMS BY X-RAY MICROTOMOGRAPHY

Thermally driven zeolite adsorption heat pumps (AHP) are an environment-friendly alternative to conventional electrical heat pumps. In this field several efforts have been done to enhance the volume specific power while maintaining a reasonable thermodynamic efficiency. In this concern, a new approach by using a composite zeolite-siloxane foam to fill open space in a traditional heat exchanger was proposed. This foam, with large surface area to volume ratio, could be a promising candidate as adsorbent material for adsorption heat pumps applications. Aim of the present work is to assess the influence of morphology and filler amount on the adsorption performances of zeolite filled siloxane composite foams for AHP applications. Digital image analysis and statistical analysis of cell size distribu- tion were performed and on this basis a water vapor diffusion model through foam was proposed.