I have a question for you:

- How is the best air flow efficiency related to the orientations, positions, and sizes of openings ?

Normally the atrium of the building can be used as a stack for naturally ventilate the building.

Have this study take this driving force into calculation ?

Well, I think  this research is very useful for designing tropical architecture. However I have a question due to the results.

The question is;

What is the optimized ratio of opening size and the volume of the artium?

Khun Sasikan, my answers to your question are as follows;

1. Building orientations: The cross ventilation results showed that the inlet openings facing toward the major wind direction could provide better ventilation efficiency results. The more inlet openings opened to the wind direction, the more amount of airflow into the building.
2. Opening positions: When the positions of inlets and outlets are more direct on the opposite side, they provide a higher amount of airflow. But when the positions of them are angled or obliqued, it causes a lower amount of airflow but having better airflow distribution.
3. Opening sizes: If the inlet to outlet sizes were about the same or the inlet is smaller than the outlet, the average speed of the airflow would be high. On the other hand, if the inlet is larger than the outlet, the airspeed would be lower but could distribute better.

It's useful reseach and good presentation that encourage me to understand how sustainable atrium designing causes many natural airflow formations in building. Strongly confirm that why Thai vernicular architectural design concept for group of family houses always have open court known as "Ruen Moo".

What is mainly concern in sustainable atrium design, in your opinion, among natural airflow, opening size,volume,orientation or others? 

Thanks to khun Korapong, my answer to your question is that my research did take wind-driven force into the simulations since natural wind affects the airflow patterns inside the atriums most.

Khun Suwicha, since my research has just analyzed the 4 existing case studies, there was no modification experiments to find the optimization results. However, the issue that you mentioned is very interesting and could be my further studies. Thank you very much.

Thanks to khun Rangsit, I agree with you that traditional Thai house is a role model for Thai sustainable architecture. Nowadays, semi-open atrium buildings have provided more comfort by; 1) optimizing the heat from the sun while still having much natural sunlight at the wide-span transparent roof. 2) providing more appropriate openings with adequate natural ventilation. 3) creating more semi-outdoor green environments, such as a garden. I think that passive-green buildings in Thailand should be promoted to have these 3 natural conditions.

Its very useful research. By the way, my question is there is any suggestion for design atrium form and volume for the best ventilation result in your opinion. 

Thanks to Khun Thee. Your question is simple but hard to tell since architectural requirements and contexts are different. By the rule of thumb, the building should perform well to catch the wind and generate airflow to all usable areas, not just pass through at the upper space. For example, the RSU building 6 (Student Center) is one of the best building forms to catch the wind through the atrium. But the multi-purpose areas under the 2 towers could not have enough ventilation because there are few openings which cause air pockets.