This study describes sensitivity studies of a kg-scale fixed bed reactor model via cycle simulations to capture CO2 from ambient air. The model involves temperature vacuum swing adsorption (TVSA) cycles and Lewatit® VP OC 1065 amine-functionalized adsorbents. In order to examine the effectiveness of direct air capture (DAC) processes, it is essential to build a comprehensive DAC model to optimize process design and cost. However, this is missing in the literature and as a result, the cycle performance of a DAC model treating CO2-containing airflows, based on transparent mass and heat transfer assumptions with adsorption isotherm descriptions is developed in Aspen Adsorption in an attempt to address the gap. TVSA capture steps (adsorption, evacuation, desorption, and cooling) are studied using the DAC model to enhance performances in terms of energy consumption, recovery, and operating costs. Lastly, to assess the viability of large-scale DAC system deployment and its significance in comparison to point source CO2 capture technologies, a kg-scale fixed bed model is scaled up and preliminary results indicate that a capture cost of 620.7 €/tCO2 can be expected which is in agreement with the current literature values.