Preparation and characterization of metal-organic framework/microencapsulated phase change material composites for indoor hygrothermal control

Building materials with high thermal and hygric inertia can moderate the fluctuation of indoor temperature and relative humidity, and thus can improve the indoor thermal comfort and reduce the building energy consumption passively. In this study, a novel hygrothermal control material was prepared based on Metal-Organic Frameworks (MOFs) and microencapsulated phase change material (MicroPCM). The new MOF/MicroPCM composite has a dual functionality of adsorption and desorption of both heat and moisture, can offer an accurate passive control of the indoor hygrothermal environment. N-octadecane was encapsulated by polymethylmetracrylate (PMMA) as MicroPCM for the thermal buffering. MIL-100(Fe) was prepared by the hydrothermal reaction method as the humidity buffering material. A series of hygrothermal control composite materials were obtained by grinding MicroPCM and MIL-100(Fe). Physicochemical properties of the synthesized materials were characterized by SEM, TEM, XRD, FTIR, N-2 physisorption, Water vapor sorption isotherm, DSC and TGA techniques. Hygrothermal properties of the composites were analyzed in comparison to pure MicroPCM and MIL-100(Fe). The thermal and humidity buffering behavior of the composites containing 50% MicroPCM was analyzed by numerical simulations. The results show that the composites possess an excellent thermal and humidity buffer capacity, which can be used for building energy-saving and improving thermal comfort.