Researchers are testing an innovative control approach to improve efficiency in buildings

Pacific Northwest National Laboratory provided original content for this article.

Early results from an experiment at Pacific Northwest National Laboratory strongly suggest that a new method known as Intelligent Load Control, or ILC, rapidly reins in a building's energy demand—without harming the comfort of building occupants. The results could help advance transactive energy concepts nationwide.

Transactive energy is achieved by implementing transactive control strategies. These strategies enable energy-related devices in buildings to continuously exchange electricity consumption and price information and negotiate and respond to that information to optimize energy use in real time. In addition to transactive energy applications, ILC can be deployed in buildings to help manage traditional utility rate structures, which include monthly demand charges.

As part of the Clean Energy and Transactive Campus project, PNNL researchers lead an experiment that employs their ILC algorithm to reduce peak electricity loads in PNNL buildings and meet a specific demand limit. The goal is to accomplish this objective in a manner that concurrently ensures occupant comfort.

Implemented earlier this year in PNNL's large 350 Building, ILC began controlling the operation of multiple heat pumps serving offices and other work spaces. Test results show that when building energy consumption peaked at different times during the day—such as the first thing in the morning —ILC quickly prioritized heat pump operations, shutting down some units while running others. The approach successfully dropped demand in some spaces to meet the established limit, and occupants did not indicate any comfort impacts.

Priorities Balance Peak Demand

One key to ILC is its use of the Analytic Hierarchy Process. AHP provides a method for prioritizing actions for the best results. For example, AHP strategies can help determine whether shutting down or turning on heat pumps in a certain sequence will achieve optimum energy savings.

To validate the initial results, PNNL researchers soon will be testing ILC in at least three other PNNL buildings. "The experiment results have been promising. We believe ILC offers significant potential to save energy costs. But more work must be done to improve and advance this technology and make it easy to configure and scale to other buildings with different types of end uses," Woohyun Kim, a PNNL controls engineer, says.

This experiment, along with others being conducted in CETC, will inform development of a "recipe" that allows entities across the country to adopt transactive energy practices. Other experiments at PNNL include:

• Deployment of diagnostic control algorithms in buildings to commission and run “calisthenics,” which identify equipment problems and correct operational control issues
• Demonstration of other market-based transactive control within buildings
• Control of commercial building loads to absorb short-term generation loss from distributed renewable generation resources

The CETC project also plans to create a research and development test bed in Washington state that will facilitate future transactive research in the emerging buildings-grid discipline. The project continues into 2017 and is funded by the U.S. Department of Energy and the State of Washington’s Department of Commerce.