U.S. Purdue University will lead a project of the US Department of Energy. (DOE) to develop sensors designed to reduce the cost and environmental impact of the operation of the heating, air conditioning and ventilation system of a building.
The new sensor is designed to continuously determine how many people are occupying a room or building by measuring changes in carbon dioxide concentration. Such an advance would allow energy savings by greatly restricting air conditioning and heating to occupied areas.
"Disconnecting heating and air conditioning sensibly would save a substantial part of US energy consumption," said Jeffrey Rhoads, a professor at the Purdue School of Mechanical Engineering, who leads the project. "To do that you need to be able to know when there is a room occupied and how many people there are."
The project, which begins in May, is funded by a three-year grant and US $ 1.5 million from the DOE's Energy Research Projects-Energy Agency through its new Saving Energy Nationwide program in Structures with Occupancy Recognition, or SENSOR.
Approximately 13 percent of all the energy produced in the United States today is used to heat, cool and ventilate buildings, and much is wasted; it is used when the buildings are unoccupied or not occupied at all. A building's ambient is to continuously measure the concentration of carbon dioxide, which is exhaled by people, said Rhoads, the principal investigator of the project. He is working with George Chiu, a professor of mechanical engineering; Bryan Boudouris, Robert and Sally Weist Associate Professor of Chemical Engineering; and James Braun, Professor Herrick of Engineering and director of the High Performance Building Center at Ray W. Herrick Laboratories of Purdue.
The new sensor combines two technologies. First, a sensor developed in research directed by Boudouris will detect the presence of carbon dioxide. Then another sensor developed by Rhoads and Chiu will make precise measurements to determine how many people are in the room.
"Our approach is to use these two sensors in concert so that only an accurate measurement of CO2 (carbon dioxide) concentration is made if someone is present in the room, which saves energy in the detection process," Rhoads said. "The first sensor detects CO2 and is used as a switch to turn on the second, and in doing so you save all the power of running the second continuously, and this strategy allows us to satisfy some key metrics on energy consumption and longevity. operate with very little power and it will last several years, we do not want a system that has to be maintained annually or monthly. "
The sensor will be a bit larger than a stamp, it will cost less than 6 cents per square foot of construction space to operate and will last more than three years. The technology is an example of a microelectromechanical system, or MEMS, which are devices that contain small microscale mechanical components. Vibration plates behave differently when in the presence of CO2. They will be coated with a film that absorbs CO2, causing a change in vibration frequency. The sensor will restart by heating the sensor components, eliminating the CO2 gas.
"You might think it's a smoke detector, except we're focused on carbon dioxide and not just detecting, we're also measuring," Rhoads said.
The research will be conducted mainly at Herrick Laboratories. Two associated postdoctoral researchers and a graduate student will also participate in the project.
Source: Purdue University.