Direct Air Capture of CO₂ in Enclosed Environments: Design under Uncertainty and Techno-Economic Analysis

CO₂ capture from enclosed environments such as commercial buildings can result in reduced ventilation, thereby leading to decreased energy loads on the HVAC systems. We propose a model which regulates the air quality inside the room by adsorption of CO₂ on monoliths coated with zeolite 13X, and water adsorption on packed beds with silica gel. We perform a modeling study and energy assessment by simulating a multi-component, multi-bed system which controls carbon dioxide level inside the room on a 24 hr basis. The results obtained indicate a 75% reduction in energy load with the CO₂ capture system as compared to the conventional ventilation system. We have identified areas of uncertainty in the model and compared non-intrusive polynomial chaos method with Monte Carlo simulations to quantify the model uncertainties. The results show improvement in computational efficiency with non-intrusive methods as compared to Monte Carlo simulations. We conclude that the CO₂ capture system can lead to improvement in building energy performance and application of polynomial chaos methods can result in reduction of computational time.