Study of the CO2 Adsorption Performance of a Metal–Organic Frameworks: Applications in Air Conditioning

Solid adsorption air conditioning use MOFs to adsorb carbon dioxide, which significantly reduces the energy consumption of the air conditioning system. In this work, the adsorption mechanism of three MOFs (MIL-101 (Cr), MIL-101 (Fe) and MIL-100 (Fe)) for carbon dioxide were analysed. The results show that all three adsorbent materials are capable of carbon dioxide adsorption and meet the requirements of solid adsorption air conditioning systems.

Abstract

Air conditioning systems introduce fresh outdoor air mainly to dilute indoor CO₂ and meet the high demand for interior environment quality. However, in some cases, introducing fresh outdoor air cannot be done, because of high pollution of the outdoor air or because there is no fresh air. In these cases, limiting CO₂ concentration can be done only through adsorption devices. In this study, innovative metal-organic frameworks (MOFs) were employed as adsorbents to handle CO₂ independently in air conditioning systems. Three different MOFs, MIL-101 (Cr), MIL-101 (Fe), and MIL-100 (Fe), were compared using a dynamic adsorption experimental device. The dynamic adsorption patterns of CO₂ on the three adsorption materials and the corresponding performance index parameters were obtained. According to the experimental findings, when the temperature was raised from 298 K to 313 K, the adsorption breakthrough times for CO₂ on the three adsorbent materials decreased from 590 s, 470 s, and 295 s to 305 s, 270 s, and 160 s, respectively. When the relative humidity was 30 % and 60 %, the carbon dioxide removal capacity of MIL-100(Fe) increased to 1.92 and 1.79 times that under dry conditions.

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