Expensive startup costs are often cited as a reason building owners and operators don’t install energy saving technology, like building controls and automation, although in general they eventually pay for themselves. As such, lowering initial costs and increasing savings to shrink this payback time is often the focus of reducing energy use.
Now a recent study by the Department of Energy’s Pacific Northwest National Laboratory (PNNL) suggests that getting users to utilize the energy-efficient systems they already have installed should be an important part of energy-saving conversations as well, at least when it comes to commercial buildings.
The study released in May found annual U.S. commercial building energy use could be cut on average by 29 percent by fully utilizing 34 different energy efficiency measures, most of which rely on building controls. These measures included fixing broken sensors, turning off power-using devices in unoccupied rooms and daylight harvesting. Researchers found that these changes could result in between 4 to 5 quadrillion British Thermal Units in national energy savings, which is about 4 to 5 percent of the energy consumed nationwide.
Commercial buildings account for 20 percent of U.S. energy use and 15 percent of these buildings already have automation systems that deploy building controls. Simply helping commercial buildings better use and properly maintain their controls has the potential for significantly lowering overall U.S. energy consumption.
"Most large commercial buildings are already equipped with building automation systems that deploy controls to manage building energy use," said report co-author and PNNL engineer Srinivas Katipamula. "But those controls often aren't properly programmed and are allowed to deteriorate over time, creating unnecessarily large power bills. Our research found significant nationwide energy savings are possible if all U.S. commercial building owners periodically looked for and corrected operational problems such as air-conditioning systems running too long."
Using building models of prototypical commercial buildings, the researchers estimated how each of the 34 measures and packages of the energy-efficiency measures would affect the energy use of buildings in three conditions: efficient buildings with little room for improvement, inefficient buildings with a lot of room for improvement and typical buildings in the middle.
They found that the measures with the greatest energy-saving potential nationwide were lowering daytime temperature set points for heating, increasing them for cooling and lowering nighttime heating setpoints; reducing the minimum rate for air to flow through variable-air volume boxes; and limiting heating and cooling to when building is most likely to be occupied. The results also showed that some commercial buildings have a much higher energy savings potential than the 29 percent average, including secondary schools (49 percent savings) and standalone retail stores and auto dealerships (41 percent).
To read the report in full, visit Impacts of Commercial Building Controls on Energy Savings and Peak Load Reduction.