Experimental study of 3D – structured adsorbent composites with improved heat and mass transfer for adsorption heat pumps

The optimal balance of heat transfer, mass transfer, and adsorption capacity is critical to enhancing the performance of adsorption heat pumps. Here, 3D-structuring of adsorbent composites is used aiming to reduce heat and mass transfer resistance to improve the performance of adsorption heat pumps. The composites are produced in a laboratory hot press by consolidating an activated carbon and binder-based suspension. By introducing percolating, thermally conductive aluminum ribs, as well as mass transfer channels into the composites, heat and mass transfer kinetic could be intensified without losing volumetric adsorption capacity to a high extend. Adsorbent composites with different structuring were dynamically investigated in a gram-scale laboratory adsorption chiller by measuring mass fluxes exchanged within an adsorption cooling cycle. For the application in an adsorption chiller, performance increases by 5% after introducing of mass transfer channels, by 42% on addition of 3D-printed aluminum ribs, and by 85% by applying both, mass transfer channels as well as 3D-printed ribs in the composites compared to non-structured composites.