In homes and commercial buildings, about one-third of electricity consumption is attributed to miscellaneous and electronic loads (MELs) — appliances like toasters, printers, fans and clocks. Many devices fall into this category; however, because of the variety of devices and the expense of the technology used to test them, their energy use is not understood very well.
Luckily, Lawrence Berkeley National Laboratory has teamed up with the University of California-Berkeley to develop a better understanding of the variety of small appliance loads, estimate their load growth and to develop inexpensive technologies to monitor them. Knowing which devices use the most energy and what their energy load profiles look like will help researchers, homeowners and manufacturers understand how to better manage their energy use.
The UC-Berkeley team developed a wireless sensor network platform that uses alternating current meters to provide data as frequently as every 10 seconds that are accurate to about 0.5 percent of the actual reading. The meters are less than three inches long and are plugged into an outlet. The device that is to be measured can then be plugged into the meter. Each meter used in the study cost about $80 and used about 1 watt of power, adding very little to the building’s electric load. The meters wirelessly transmit the data back to a central database.
The team tested the energy use of MELs in both residential and commercial settings. Two existing homes in California and one net zero home in Massachusetts made up the residential sample, with 75-80 meters per home. The commercial sample consisted of an 89,000-square foot office building at Berkeley Lab housing about 450 occupants, with about 460 meters placed throughout the building to serve as a representative sample across a wide range of device types.
In the office building, the most common devices were computers, computer displays and other peripherals such as printers and external drives. The team found that most computers are in the “on” mode almost all the time, but a significant number of computers are powered down much of the time. Likewise, displays in the building are rarely left on.
Providing information like this to a building energy manager would allow them to empower employees to take simple steps to improve the efficiency of their work space, such as asking employees that never turn off their computers to enable their energy-saving low power mode.
Now, the research team is exploring low-cost methods to measure electricity use of electronics through technology integrated into the appliance itself. This would allow for a much richer data profile of a building’s energy use. The team is also working with the efficiency community and manufacturers to reduce the energy use of electronic devices by developing advanced controls and reducing power use while the devices are operational.
Learn more about the National Labs and their work to help consumers and businesses save energy and money.