IntroductionArchitects are reconsidering natural ventilation due to environmental concerns and increasing energy consumption in recent years. An atrium building with a large glass area is now incorporated with the content of modern building design to make best use of solar energy and buoyancy-controlled ventilation. The excellent design of the atrium building will contribute to respecting the environment and minimizing energy demands. The natural ventilation strategy in atrium building includes buoyancy and solar-driven air flows through the interior, a multi-storey atrium building with solar chimney system requires further research to study the reduction of energy consumption using the buoyancy-driven ventilation. will simulate the air flow and heat transfer of the building design and examine natural ventilation strategies, computational fluid dynamics (CFD) technology will be used. CFD can successfully simulate the air fluid and related temperature distribution within the building and produce sufficient data to analyze heat transfer and turbulence while the building is subjected to natural ventilation. Thermal comfort can be expressed as “satisfaction with the thermal environment is expressed by the conditions of mind” by ISO 7730. The predicted mean rating (PMV) and the predicted percentage of dissatisfied (PPD) are the most common standards for evaluating thermal comfort. This thesis aims to study the heat transfer and air flow and temperature distribution of a multi-storey atrium multi-building environment with buoyancy-driven ventilation and evaluate how the thermal comfort of occupants changes in atrium buildings with different construction elements. This thesis plan is divided into 5 parts, the first...... half of the sheet...... The relevant calculation procedures for calculating the PPD value and evaluating comfort thermal Expected results Building design Figure 9 shows the visualization of the building design drawing with Sketch up The buildings are made up of different structural and decorative elements, which involve the glass area, the opening dimensions and the height. of the fireplace, etc. Temperature. The expected result of the thesis would include details of the graphical temperature distribution in the entire building produced by CFD. (Figure 9) Predicted Percent Dissatisfied (PPD) The parameter to measure thermal comfort, PPD, which should be generated as an XY graph, which should contain several construction components to analyze the effect on the performance of natural ventilation in the building atrium. (Figure 10) Working hours