Studies on equilibrium and dynamic characteristics of new adsorption pairs
In this thesis, research on kinetic and equilibrium state properties of some new adsorption pairs and non-equilibrium models are investigated. In the first part, the equlilibrium characteristics of adsorption pairs using carbon dioxide as adsorbate are studied. The results showed that the performance of this kind of adsorption system is poor due to the low latent heat of carbon dioxide. New composite ammonia adsorbents, 12.3 wt. % CaCl2/C (3C), 17 wt. % CaCl2/Aluminia (SWS), and 59 wt. % BaCl2/vermiculite, were synthesized and studied. It was found that the modification of host matrices by the salt dramatically increases the ammonia uptake. Hysteresis between the synthesis and decomposition reaction was found and the van't Hoff equation was applied to describe the hysteresis. In the second part, kinetic experiments of the composite ammonia adsorbent, 59 wt. % BaCl2/vermiculite, were performed under isothermal conditions and conditions that would be experienced in a real system. Based on the experimental data, a modified linear driving force (LDF) model is used to simulate the dynamics of adsorption pair. In the model, two resistant constants were obtained empirically from the experimental data. In the third part, the dynamic model of concentration change with heat and mass transfer equation were used to simulate the performance of adsorption system. The results were very encouraging with a maximum COP of around 0.8 and a maximum SCP of around 600W kg-1 in an air conditioning application with one-bed basic cycle. Further studies could focus on the commercial analysis of this promising material in air conditioning. A real lab-scale compact bed could be set up and tested for the performance of adsorption pairs.