Metal-organic framework MIL-100(Fe) as a novel moisture buffer material for energy-efficient indoor humidity control

Metal-organic frameworks (MOFs) are a new class of porous materials composed of a three-dimensional network of metal ions held in place by multidentate organic molecules. MIL-100(Fe) (molecular formula: Fe3O(H2O)2OH(BTC)2), as one kind of MOFs, has an excellent performance of water sorption due to the large specific surface areas and high porosity. The paper proposes an innovative application of MIL-100(Fe) as a new kind of moisture buffer material to control the indoor humidity passively. MOFs can moderate indoor moisture fluctuation, which will greatly reduce the energy consumption of HVAC systems and improve the building energy efficiency. In the paper, microstructure and moisture characterizations of MIL-100(Fe) have been carried out. The moisture buffer value (MBV) of MIL-100(Fe) has been measured and compared to the typical building materials. The results show that MIL-100(Fe) can absorb up to 15 g m−2·RH−1 at 8 h, which is 33 times higher than the laminated wood. A novel lumped model for building latent load simulation has been developed. The energy saving potential by using MOFs in a typical office in different climates was calculated. The results show that a 5 m2 MOF wall panel can remove most of the latent load in dry and moderate climates without any energy input; MOFs can be regenerated by night ventilation. In the hot and humid climate, the MOF materials can remove 73.4% of the latent load, and can be easily regenerated by using low-grade energy.