Research: Engineering News

Device Raises Awareness of Energy Use

Did you know that a DVR can use more energy than a television?

Anthony Rowe, assistant research professor in the Electrical and Computer Engineering Department, knows exactly how much energy his home appliances use. "My DVR is the third biggest energy consumer in my apartment today," said Rowe, pointing to a graph on his computer. He can pull up an energy profile for his refrigerator to make sure it is working correctly and can even turn on his bedroom light from his office.

Rowe's home appliances are all connected to wireless sensor nodes, individual sensors that gather remote information and link to a larger network. The nodes are little black boxes that function like adaptors, plugging into an outlet and connecting to an appliance. Inside each node are sensors that measure an appliance's energy output while recording the area's environmental conditions like light, temperature and vibration. The nodes also contain wireless transmitters that send signals to a receiver, which collects and delivers the data to a web interface, called Sensor Andrew Gateway Agent (SAGA). It is through this interface that Rowe observes and controls his appliances.

The sensor nodes are part of Carnegie Mellon University's FireFly Wireless Sensor Network, a low-cost and low-power hardware platform that collects and transfers data in real-time. It is only in the last two years that Rowe and his collaborators began developing energy monitoring applications for the FireFly technology with funding from the National Science Foundation.

The purpose of the sensor nodes is to generate awareness about energy use. Right now there are six houses being detected and the data from these homes will reveal important information about energy habits. Like Rowe, participants can access their accounts through the SAGA interface and observe their own appliances. "In the future," says Rowe, "this technology and the data it collects will be vital in helping utility companies shift peak usage periods for power-hungry appliances." This would help avoid blackouts and reduce the need for new power plants. The information can also be shared "to educate homeowners about energy waste and encourage them to cut down or divert their usage to off-peak times."

One major concern for broader application is privacy because the sensors are capable of exposing information about lifestyle patterns. To investigate this, Carnegie Mellon CyLab is dedicating a student to study the privacy issues.

Collaborators on this interdisciplinary project are professors Raj Rajkumar of ECE, Lucio Soibelman and Mario Berges from CEE, and CEE Department Head and Co-Director of CenSCIR James Garrett. Carnegie Mellon | Portugal is also involved, but working on independent research.

So back to our question: How does that DVR use more energy than a TV? "It's on all the time," says Rowe. While his TV requires more power to operate, the SAGA energy profile reveals that his DVR's total energy usage is greater.

By Rebekka Blaha

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