INVESTIGATION OF WATER-VAPOR ADSORPTION ONTOMETAL-ORGANIC FRAMEWORKS (MOFS) FORGREENHOUSE AIR-CONDITIONING APPLICATION

摘要

Metal-organic frameworks (MOFs) are provid- ing a new class of organic desiccant materials thatpossess interesting physical and adsorption charac-teristics. In this study, MOFs of type (i) HKUST-1,(ii) CPO-27(Ni), (iii) MIL-101(Cr) and (iv) MIL-53). are studied for greenhouse desiccant air-condition-ing application. Water vapor adsorption equilibrium data of the MOFs are obtained from the literature. The adsorption equilibrium models of Dubinin-Asta- khov (D-A) and Guggnheim-Anderson-de Boer (GAB) are used to represent the adsorption uptakedata, and thereby adsorption isotherms are devel- oped for various temperatures. Optimized parame- ters of the models are provided accordingly. Among the studied MOFs. the MIL-101(Cr) shows the high- est water vapor adsorption uptake of 1.45 kg/kg at a relative pressure of 0.90 and temperature of 25°CC The CPO-27(Ni) exhibits type-l adsorption isothermaccording to IUPAC classification. Greenhouse air- conditioning application is studied for three demand categories based on required relative humidity of 60%, 40%, and 20%. Steady-state moisture cycled by the MOF based desiccant system is estimated. It has been found that different MOF adsorbents pro- vide optimum desiccant unit based on available re- generation temperature. Results showed that the CPO-27(Ni) is not found applicable for required RH < 20%, whereas, MIL-101(Cr) and MIL-53 are ap- plicable for all RH ranges.