A Living Laboratory for Energy Systems Integration
NREL is collecting, storing, analyzing, and displaying its building energy performance data to manage and optimize campus energy use.
The National Renewable Energy Laboratory (NREL) often prides itself on being a "living laboratory" for clean energy technologies. This became most apparent in 2011 with the opening of the Research Support Facility (RSF), an award-winning, energy-efficient office building that generates enough electricity to meet its energy needs over the course of a year. But now a new effort is bringing all of the buildings on the NREL campus—old and new—into the fold, making the entire campus a living laboratory.
This effort, called the Campus Energy Portfolio, is part of a growing NREL emphasis on energy systems integration, which ensures that all the energy-generating and energy-consuming technologies work together as efficiently as possible to yield the optimal benefits for the laboratory. The Campus Energy Portfolio tapped experts from several analysis and research centers across NREL to study how to optimize the campus's energy use.
The Energy DataBus
The backbone of this project portfolio is the Energy DataBus—software that collects and stores information from all sensors and meters on campus. In early 2011, NREL embarked on a project to gather data from the hundreds of electric, natural gas, and water meters throughout the campus. It collects information from these meters, as well as from heating, lighting, electric vehicle charging, and renewable energy systems, at second-by-second intervals, 24 hours per day, and stores it all in one giant database. And the use of the word "giant" is no exaggeration.
"Historically, when you have facilities looking at data, they may look at data from their meters every 15 minutes. We wanted to look at very high-resolution data," says Aaron Beach, Energy Informatics researcher.
As a result, nearly half a million data points stream into the database over the course of an hour. That adds up to more than 4 trillion data points per year. Fortunately, the people working on the project had the foresight to plan for the large volume of data.
"We didn't want to just go collect data and stick it into whatever database we had available and then realize a month later that the amount of data we were collecting was so large no regular database could handle it," says Beach.
Instead, the team developed an open-source solution that is designed for large, scalable databases.
"It's similar to the one that Facebook and Twitter use to collect all this data and information on people. We're using the same giant, scalable capability to collect energy data," says Beach.
The trick is to make sense of all that data. The NREL project team's timing was excellent, though, in that right now, "big data" is a buzzword in science, and researchers from a wide range of scientific disciplines are working to "mine" those valuable nuggets of information hidden in large databases. In fact, NREL's Brian Bush was working on just such a project when he was brought on board for the Energy DataBus project.
"No matter what you do, when you start collecting data off meters, you get bad data, you get data dropouts, you get all sorts of issues," Beach explains. "So we worked with Brian to create some tools that would eventually be used to clean and pull out relevant information from the datasets. Brian used some advanced computational techniques to do things such as fill in missing data and identify bad data in the system.
"Being able to mine the data and perform some analytics on it helped us pinpoint where potential issues were with some of the control strategies in RSF, for instance. So it's helping us refine the control strategies in the existing buildings."
Campus Energy Visualization
So what does NREL do with all this data? As another part of the Campus Energy Portfolio, the laboratory is developing a number of visualization applications that interact with the database. From campus heat maps to displays of current weather conditions, these applications help "behind the scenes" facility managers optimize campus energy usage. Perhaps the most visible of these applications is the campus energy dashboard, which presents a big-picture view of energy use on the campus, and also allows users to drill down into the data to examine specific trends.
For the campus as a whole, the dashboard displays a single analog dial, like the speedometer on a car dashboard, but instead showing energy use in kilowatts. The dial has a small, tightly defined white area that shows the campus's expected range of energy use at that moment.
"The white sector is the expected range based on energy simulations and energy usage for the past couple of years," says NREL's Larry Brackney, whose group helped create the dashboard. "It's based on the time of day, the day of the week, whether it's a holiday or not, and the current weather."
If more energy is used than expected, the dial moves into a red zone, while lower than expected energy use lands in a green zone. The campus display also shows the energy use for each building, so if campus energy use is high, users can tell at a glance which buildings are responsible.
Selecting one building causes the dashboard to display the building's energy performance as a set of analog dials. These dials reflect subcategories of energy use within that building, such as heating, cooling, lighting, plug loads (the energy used by items plugged into outlets, including computers), and mechanical equipment such as fans and pumps.
For each building on campus, users will be able to drill down into the data by clicking on one of the energy subcategories. Doing so yields a trend plot of recent performance data that can be viewed at scales as short as an hour and as long as an entire day, or users can view all of the data available. These detailed trend plots allow facility managers to identify when energy trends deviate from expected patterns, suggesting that equipment may need maintenance or adjustments.
Engaging the Building Occupants in Building Energy Use
The Energy DataBus also interacts with an application that encourages the occupants of each building to contribute to that building's energy savings. The application, called the Building Agent, was initially launched as a stand-alone application for the RSF that was loaded on all the building occupants' desktop computers.
"Building Agent allows occupants to give feedback more quickly to building energy managers, which can substantially improve occupant comfort and reduce energy use" said Nick Long, NREL research engineer.
An example is the fact that the RSF is equipped with operable windows, but the building energy manager wanted to restrict the opening of these windows to times when it would benefit the building's energy profile. To achieve that goal, the Building Agent displays a message on office residents' computer desktops, telling them when they can open windows (if they so choose) and when they need to close them.
That desktop tool has since been expanded, allowing occupants to also give feedback on their comfort levels. They can indicate whether their environment seems hot or cold, humid or dry, stale or breezy, quiet or noisy, or if they are dealing with glare. This data feeds back into the Energy DataBus. In the near future, the energy dashboard will allow building managers to view a spatial representation of this data against the building's floor plan, with the option of overlaying temperature and humidity sensor data from the building with the comfort levels the building's occupants report.
The Building Agent will eventually expand to include the entire NREL campus, and it may also expand to include more occupant interaction. For instance, most of NREL's office workers now use laptops that plug into desktop work stations. During times of peak power demand, one option to cut energy use would be to ask occupants to unplug their laptops and run them on battery power for a short while.
"Our goal here is to come up with ways so that anybody—not just facility people, not just researchers—can understand how they affect energy use," says Long. "It's finally connecting people to energy use, and it's making it easier for them to understand what their impact is on the rest of the system."
Looking to the Future
The NREL Campus Energy Portfolio and all of its associated applications will certainly help NREL manage energy use on its campus. Yet the project leaders have bigger goals in mind. One is to use building energy models such as EnergyPlus to model the energy performance of all the buildings on the NREL campus. Energy modeling is a valuable tool for understanding the complex synergies between building design, operation, and energy use.
Taking it to the next level, NREL researchers are designing tools to investigate how to design and control larger interconnected energy systems, beyond single campuses, for integrated energy management. This integrated approach could include making decisions about dispatching energy-generating systems, performing system diagnostics, and enabling continuous improvement.
NREL also takes a unique market-relevant approach to all its efforts, and the Campus Energy Portfolio is no exception. Campus Energy Portfolio software has been designed to be a platform for sharing with others, allowing organizations to adopt the platform for their campuses and to customize their energy application interfaces. This customization will allow others to easily use applications such as the energy dashboard and NREL's Building Agent.
To achieve that goal, the Energy DataBus uses open-source software. Open-source software allows for maximum collaboration, because outside users can customize the system and add new features, if they wish. In addition, the scalable nature of the database allows it to be scaled up for larger applications, such as for a community.
"The plan is to roll this platform out to the public in open source format so that university campuses and other institutions can tap into these tools and build off of them," says Beach.