Ambient wind direction impacts on the performance of a CO2 direct air capture system determined using large eddy simulations

Direct air capture (DAC) has emerged as a promising technology for the direct removal of carbon dioxide (CO 2 ) from the atmosphere, offering a pathway to mitigate global warming. In this study, we employ the large eddy simulation (LES) approach to predict the combined effects of atmospheric boundary-layer wind speed and wind direction on the performance of a representative DAC system. We use LES coupled with our in-house boundary condition (atmosDacBoundary) code to calculate the total mass of CO 2 captured by the DAC system. The results demonstrate that with the introduction of wind, the DAC inflow velocity begins to fluctuate, resulting in time-varying amounts of CO 2 captured by the DAC unit. It is found that wind speed and direction have a significant impact on the annual amount of CO 2 captured. For a given wind angle, the annual CO 2 capture amount reduces with an increase in wind speed. For all investigated wind speeds, the annual CO 2 capture amount generally reduces with increasing wind angle relative to the DAC unit inlet. It is revealed that in the presence of wind, the maximum CO 2 capture is obtained when the DAC inlet is aligned with the wind direction (wind angle of 0°), while the minimum CO 2 capture amount occurs when the approaching wind angle is nearly perpendicular to the DAC unit inlet. Understanding this process is essential for optimising the location and orientation of DAC facilities, required for optimising the performance of DAC systems for large-scale deployment.