Air-Con Metal–Organic Frameworks in Binder Composites for Water Adsorption Heat Transformation Systems
journal contributionposted on 07.11.2019, 14:37 by Serkan Gökpinar, Sebastian-Johannes Ernst, Emrah Hastürk, Marc Möllers, Ilias El Aita, Raphael Wiedey, Niels Tannert, Sandra Nießing, Soheil Abdpour, Alexa Schmitz, Julian Quodbach, Gerrit Füldner, Stefan K. Henninger, Christoph Janiak
Metal–organic frameworks (MOFs) currently receive high interest for cycling water adsorption applications like adsorption heat transformation for air-conditioning purposes. For practical use in adsorption heat pumps (AHPs), the microcrystalline powders must be formulated such that their high porosity and pore accessibility are retained. In this work, the preparation of millimeter-scaled pellets of MIL-160(Al), Al-fumarate (Basolite A520), UiO-66(Zr), and Zr-fumarate (MOF-801) is reported by applying the freeze granulation method. The use of poly(vinyl alcohol) (PVA) as a binder reproducibly resulted in highly stable, uniformly shaped PVA/MOF pellets with 80 wt % MOF loading, with essentially unchanged MOF porosity properties after shaping. The shaped pellets were analyzed for the application in AHPs by water adsorption isotherms, over 1000 water adsorption/desorption cycles, and thermal and mechanical stability tests. Furthermore, the Al-fum pellets were applied in a fixed-bed, full-scale heat exchanger, yielding specific cooling powers from 349 up to 431 W/kg (adsorbent), which outperforms the current commercially used silica gel grains in AHPs under comparable operating conditions.
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air-conditioning purposesMILfreeze granulation methodAHPwater adsorption isothermsadsorption heat transformationsilica gel grainsmicrocrystalline powdersMOF porosity propertiesheat exchangerAl-fum pelletsPVAadsorption heat pumpsstability testscycling water adsorption applicationsBinder Compositesmillimeter-scaled pelletspore accessibilitycooling powers