Heating, ventilating, and air-conditioning (HVAC) technology keeps growing towards providing people with good thermal comfort and indoor air quality. Most buildings use a centralized air-conditioning system in which the air-handling configuration of variable air volume (VAV) system focuses on controlling the zone temperature. But, some of the areas in the zone facing under-actuated and over-actuated airflow lead to the distortion of thermal comfort. Some indoor areas get too cold, and some get too hot due to improper air distribution. The indoor temperature inconsistency will affect the occupants' productivity and work performance. The main focus of this research is to improve the indoor environment's thermal performance by implementing an active air damper as an air controlling device for a centralized air-conditioning system. Indirectly, this will provide the control of temperature for a specific area in the zone with a VAV system. This paper presents the simulation results on the effect of the air damper pattern and its opening parameter against the temperature and airflow distribution in enhancing the thermal comfort performance. The simulation was performed using Ansys FLUENT to analyze three types of air damper patterns: iris, butterfly and radial. The comparison of CFD simulation results shows that the iris damper pattern can provide an acceptable range of temperature of 22 ºC to 24 ºC, which is significant to the desired thermal comfort. The uniform airflow distribution across the indoor area is obtained with no back-flow form in the ducting. Besides, there is a substantial temperature increment when the opening area of inlet airflow is reduced. Therefore, it can be concluded that the iris damper pattern is the best selection for an active air damper since it can provide the best temperature and air flow distribution performance compared to the butterfly and radial air damper.

The topic of maintaining thermal comfort efficiency in the heating, ventilation and air conditioning (HVAC) sector has always been tricky due to numerous challenges. The study focused on the challenge of under-actuated zones in non – residential and commercial buildings. The active iris damper with the integration of thermal controller is proposed to control the indoor temperature. Besides, integration of PID control strategy will be a tempting control system in enhancing the thermal performance of the building. Again, the PID controller has proven good compatibility as a primary closed-loop mechanism to maintain a comfortable room temperature. The development of the control system is done through the Arduino platform with LabVIEW as the front panel and data logging platform. The Heuristic tuning method was employed to obtain optimal gains for P, PI and PID controllers. The performance of each controller was tested by observing their ability to maintain steadily at the desired temperature set point. These tests conveyed that the best controller for this application is the PID controller. It reached the desired temperature set point and maintained it even with a temperature disruption. This study indicates that an active iris damper can effectively maintain the thermal comfort performance of indoor environment with the implementation of PID strategy, thus remedying some of the problems faced by centralized air-conditioning systems.