Development of New Zeolite 13X/CaCl2 Composite Adsorbent for Air-Conditioning Application

Composite adsorbents synthesized from zeolite 13X and CaCl₂ were investigated for applications in solar adsorption systems. The effect of Ca-ion-exchange on the adsorption properties of zeolite 13X was studied. Sodium ions in the zeolite structure were replaced by calcium ions by ion exchange. It was found that the Ca-ion-exchange process decreased the specific surface areas of the Ca-ion-exchanged zeolites while the total pore volumes were increased. The optimized Ca-ion-exchange condition existed when soaking zeolite 13X in 46wt% CaCl₂ solution for 36 hours. The increase in the total pore volume is good for further impregnating the zeolite with CaCl₂. A large difference in equilibrium water uptake, 0.404g/g, between 25°C and 100°C under 870Pa was recorded for the 13X/CaCl₂ composite adsorbent impregnated in 40wt% CaCl₂ solution. This was 295% of that of zeolite 13X under the same condition. The 13X/CaCl₂ composite adsorbent showed a high potential in replacing vapor compression chillers in producing chilled water for central air-conditioning systems.