SAN JOSE, Calif. — Researchers at PARC aim to develop a platform for distributed sensors made on a flexible substrate and powered by a 900-MHz RF link. The work is one of 18 building-automation projects funded by the U.S. Department of Energy geared to reduce wasted energy.
PARC hopes to stage demonstrations within 18 months of peel-and-stick temperature and humidity sensors and an RF hub to power them. The sensors target costs of less than $10 while the hub would send micro-joules of energy distances initially up to 10 meters and cost less than $100.
The RF hub will use multiple antennas in different combinations to detect when a sensor receives a signal and automatically steer power to it. The approach enables anyone to deploy and move the sensors and hubs as needed without needing to calibrate the system.
An RF hub powering distributed sensors could cover a room or a floor of a building. (Images: PARC)
The sensors will use as many as 10 chips mounted on a plastic substrate, including a capacitor to store energy. Another group at PARC aims to develop automated techniques for mounting chips of different sizes on flexible substrates. Traces between chips are printed on the plastic using inks with silver nanoparticles.
Overall, “it’s really a platform that could include gas sensors for air quality or other things,” said David Schwartz, who manages the energy devices and systems group at PARC, a research subsidiary of Xerox. To the best of his knowledge, “no one is using RF to power distributed flexible sensors.”
Among the other 18 projects announced in July, Oak Ridge National Lab also is developing a distributed network of peel-and-stick sensors, but the lab is using indoor photovoltaics to power it. Schwartz said that PV tends to be more expensive and requires lights to be on.
Only four of all of the DoE grant winners are private-sector companies. Others working on sensors include a system at Carnegie Mellon to sense occupants in a building and adjust HVAC settings accordingly. Berkeley researchers are designing wireless sensors to enable a demand/response electrical system.
Buildings are the country’s largest energy consumer, racking up a total annual energy bill of $430 billion, the DoE said. Nearly a third of the energy is wasted, setting up the potential to save $80 billion a year with just a 20% savings.
Other projects in the program include an electrical and thermal storage system for buildings being developed at Oak Ridge and a new and more efficient type of insulation in the works at Lawrence Berkeley Lab. In addition, Glint Photonics of Burlingame, CA is developing a system that uses optics and light guides to maximize daylight inside a building, and the University of Miami is creating a tool to design more energy-efficient data centers.
Sensors link through the RF hub to a building management system.
— Rick Merritt, Silicon Valley Bureau Chief, EE Times