Development of an energy efficient indoor air treatment intelligent system


Gokongwei College of Engineering


Mechanical Engineering

Document Type

Conference Proceeding

Source Title

Proceedings - 9th Asia Pacific Conference on the Built Environment 2007: "Sustainable HVAC and R Technology"

Publication Date



In the field of air-conditioning, trapped carbon dioxide in indoor environment has been contributing to health problems. Because conventional methods of removing carbon dioxide is not acceptable due to the high energy cost it entails, we engineers must find other ways to balance the promotion of a healthier indoor environment and energy conservation. This thesis project aimed to strike a balance between indoor air quality and energy usage through automation of the ventilation system via electronics and computer software. A program was encoded such that the fan will switch on and the dampers open at certain angles as the CO2 concentration approaches threshold of 1000 ppm. The dampers were installed for the recirculating air, make-up air and the exhaust air. In addition, heat exchanger was installed in the HVAC system. This acted primarily as an economizer providing air exchange of temperature of the make-up air and the exhaust air. The target venue for this project was for classrooms and offices. As simulation of such, the Aircon Laboratory of DLSU-Manila was used with an average of 13 occupants based from ASHRAE standard of occupant per floor area. We have proven that CO2 concentration will rise if there is no ventilation for an indoor environment. We introduced an automated air treatment system controlled by a LabVIEW logic computer program that will automatically regulate the amount of CO2 level inside the conditioned space with respect to the power consumption of the air-conditioning system. Furthermore, the researchers tested the system in different angle damper openings representing the various conventional ways of ventilation. As a conclusion, the data proved that the usage of the program has given a balance between energy consumption and good indoor air quality. It has consumed lower energy usage while controlling the amount of carbon dioxide content inside the laboratory. The utilization of the program for the laboratory has saved 3.5KW per day, or 800KW for the whole year in comparison with a fully functional non-automated system. The energy saved is enough to sustain electricity to three to four barangays (of thirty household each) for half a year. On the other hand, a four-year time can shoulder the additional equipment such as the heat exchanger, ducting system, actuators, and the microcontrollers.



Mechanical Engineering


Air conditioning; Energy consumption; Heat exchangers; Indoor air quality; Ventilation

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