Theoretical and experimental investigation on characteristics of adsorption cooling systems using advanced porous materials

Bonyadi, Nima
The solid sorption cooling systems are getting more popular around the globe due to their benign behavior and possibility to work with renewable energy. Despite many advantages, the overall efficiency of adsorption cooling systems is still low in comparison to vapor compression chillers. Researchers declare that heat and mass transfer and adsorption capacity inside the adsorbent bed have dominant role on the performance of the cooling unit. One way to increase both adsorption capacity and heat distribution inside the bed is by improving the characteristics of the adsorbents. Enhancing the adsorption characteristics of adsorbent materials can be achieved by developing new composites and mixtures. Using impregnation method and metal piece additives increase the adsorption capacity and thermal conductivity of the adsorbent. This thesis is an integration of three related works. In the first place, the influence of thermal conductivity on adsorption and desorption processes were investigated numerically. Next, the silica gel adsorbent was modified using metal mixture and impregnation methods. In the last step, the thermo physical and adsorption properties of new materials like adsorption capacity, thermal conductivity, heat capacity and pore size were determined in a set of experimental studies. The numerical results show that thermal conductivity affects the equilibrium adsorption behavior and using materials with higher thermal conductivities yield to lower cycle time. Higher thermal conductivity values have been obtained for new materials in comparison to silica gel. Also, pore size and diameter of the impregnated materials have been increased. On the other hand, water adsorption capacity of impregnated materials increased significantly. However, addition of metal additives decreased the adsorption rate slightly which is mainly due to the lower mass of adsorbent and higher mass transfer resistances.


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Citation Formats
N. Bonyadi, “Theoretical and experimental investigation on characteristics of adsorption cooling systems using advanced porous materials,” M.S. - Master of Science, Middle East Technical University, 2014.