Quantitative evaluation of carbon materials for humidity buffering in a novel dehumidification shutter system powered by solar energy

Abstract Recently, solid dehumidification systems have been widely used in various industries and are effective in buffering the humidity in the environment. The dehumidification materials and structure of the system have a significant influence on the over system performance. This study aims to quantitatively evaluate dehumidification materials produced from activated carbon fibre cloth (ACFC) and coconut-shell activated carbon (CAC) for suitability in a dehumidification shutter system. First, the physical and chemical properties of ACFC and CAC were characterised via N2 adsorption–desorption isotherms, thermogravimetric analysis, and Fourier transform infrared spectroscopy. Second, the adsorption of water vapour was experimentally investigated, including adsorption kinetics, adsorption isotherms, and thermodynamics, and fitted by various models. The results show that the specific surface areas of ACFC and CAC were 1425 m2/g and 986 m2/g, respectively, while the total pore volume were 0.748 cm3/g and 0.554 cm3/g, respectively. At a relative humidity of 98% and an adsorption temperature of 298 K, the maximum water vapour adsorption capacities of ACFC and CAC were 395.6 mg/g and 277.6 mg/g, respectively. More importantly, ACFC retained a high adsorption capacity after five adsorption/regeneration cycles, indicating that it is an effective and renewable adsorbent for dehumidification. Third, a novel dehumidification shutter system was designed and constructed. The dehumidification performance and thermal comfort indices of the system were then analysed. In conclusion, the dehumidification shutter system fabricated using ACFC is a feasible and effective way to buffer the indoor humidity when solar energy is chosen as the renewable regeneration heat source.