Pictured here is Michael Brambley in front of equipment that supplies chilled water to PNNL Building Diagnostics Laboratory's air handler. The cooled air from an air handler is distributed to terminal boxes, which are the last point for controlling air temperature and flow before distributing it throughout a building zone. In a new control strategy for commercial buildings, the terminal boxes would process the information collected by occupancy sensors to control the air handler's fan speed for energy savings. | Photo courtesy of Kristin Nolan, freelancer.
Every year, the United States spends about $200 billion to power commercial buildings. Yet, more than 30 percent of that energy could be saved with more efficient technologies and better building maintenance. As a researcher at the Pacific Northwest National Laboratory (PNNL), Dr. Michael Brambley is working to improve the energy efficiency of our nation’s buildings. From using computer models to analyze potential energy savings to developing tools to monitor a building’s energy use, Dr. Brambley is marrying engineering and computer technology to cut energy waste in commercial buildings.
Question: How did you end up working on building energy efficiency?
Michael Brambley: That goes way back to graduate school. I had funding from my advisor to work on a regional energy problem that turned out to be building energy efficiency. One of the major things I looked at was the performance and impact of window devices -- such as shade screens or films -- on the energy consumption of homes. It wasn’t until I got to PNNL that I started working on computer-based applications and developing automated tools that promote energy efficiency in building design and operation.
Q: You helped author a new report that finds that commercial buildings could save tens of thousands of dollars on their energy bills by adding an occupancy sensor to their ventilation fans. Can you explain how this small change leads to big energy savings?
MB: Today during a building’s operating hours, the minimum airflow (or ventilation) provided to spaces is the amount required for a fully occupied room -- whether there are people in that room or not. The problem is, when no one is in the room, you don’t need all that ventilation -- there's nobody there to benefit from it. If we can reduce the speed of the fans to match the number of occupants in spaces when we’re just ventilating, we can save a lot of energy.
In the report, we propose using sensors under development that count the number of people in a room -- these are different than the lighting motion sensors that we’re familiar with -- to control the rate of airflow into the room. And we found that on average large buildings across the country would save 18 percent of the building’s total energy consumption by making this change -- with a small portion of that savings coming from using occupancy sensors to also turn the building’s lights on and off.
Q: What can you never start your day without?
MB: The first thing is waking up -- I can’t start my day without that. But the key thing is the communications brought to me by email. The first thing I do when I get to the office is to go through my email.
Q: What are you currently working on?
MB: I am working on demonstrating in the field a technology called a smart monitoring and diagnostic system. This technology is a hardware package that you put on a rooftop unit (RTU) air conditioner or heat pump on commercial buildings to track the unit’s performance. When there’s a change in performance (good or bad), it gives off an alarm. The purpose is to alert building owners and operators that there is degradation in the unit and inform them of how much extra they are spending when they don’t service the equipment.
The other project that is really exciting is the RTU network. We’re looking at enabling RTUs and other appliances in commercial buildings to interact (or transact) with the electric power grid and other outside organizations to improve the energy efficiency of the building. It will also help improve the interaction between the grid and the buildings, minimizing electricity costs.
Q: What technology have you developed that has made the biggest difference in energy efficiency?
MB: The projects that I am working on now will probably have the biggest impact.
But about 10-15 years ago, I led a team that developed something we called the Whole-Building Energy Diagnostician and it later became known commercially as Energy Expert. The system monitors the energy consumption of a building, automatically detects when the building’s energy consumption goes up and then shows you how much you saved by fixing the problem in the building. PNNL and the company that commercialized the technology won a Federal Laboratory Consortium Award for Technology Transfer -- an award given to recognize excellence in transferring U.S. government-sponsored technologies to the public and private sectors.
Q: What’s your favorite tool in the lab?
MB: PNNL’s Intranet and access to the Internet -- it is amazing the amount of information we have access to at our fingertips now compared to when I was a graduate student.
Q: What is better when it comes to saving energy: intelligent buildings or informed users?
MB: Both are critically important. For homes, it’s informed users because there is a more manageable number of things that consume energy, and it is easier to change your individual behavior. In commercial buildings, there is so much equipment and such a small maintenance staff that it is impossible to stay informed of all the equipment that is running. If we are going to have any hope of keeping commercial buildings in peak operating efficiency, we need to have smart systems that do some of that work for us.
Q: What is one piece of advice for students interested in a science career?
MB: Get engaged in a real project by either deploying things in your field of interest or working side-by-side with scientists and researchers. This will allow you to see how the [scientific] process works, share your ideas with professionals and start making contributions in your career as early as possible.
Q: What do you enjoy doing in your free time?
MB: Free time? When I can find a little bit, I like to ride my motorcycle, visit my three granddaughters in California or go out to dinner with my wife.
Q: What is your best tip for saving energy?
MB: Make sure you’re not consuming energy when you don’t need to. You only need to run your home’s equipment -- whether it’s your lights, heating and cooling systems, or electronics -- when you benefit from it.