Guest author: Jonathan Lemmond, Senior Engineer for Baumann Consulting
Today, a commercial building energy audit requires engineers to be on site and usually costs at least $5,000. Without state or utility rebates, most building owners and operators are rarely willing to pay these costs.Then, dollars are lost on energy efficiency improvements that could be as simple as minor human behavioral changes or identifying and replacing the most inefficient equipment or leakiest windows.
In the future, we will improve the effectiveness of energy audits by making building energy data easier to collect and visualize. The information will be in near real-time and small adjustments based on that information will mean major improvements in efficiency, reducing the costs of maintaining and operating a building. Researchers and engineers at the University of California (UC), Berkeley, Lawrence Berkeley National Laboratories (LBNL) and Baumann Consulting are working on making energy audits easier to conduct and visualize once the data is collected. Their invention is called the Rapid Building Energy Modeler (RAPMOD).
The RAPMOD makes a 3-dimensional virtual model of a building and automates much of the work required to conduct various aspects of a traditional building energy audit. At first glance, the device resembles the Proton Pack from Ghostbusters, or perhaps a futuristic jetpack. In reality, RAPMOD is a backpack made of cameras, laser scanners, sensors, and other hardware.
RAPMOD is able to:
- Laser scan the inside of an entire building and generate a 3-D model
- Enable engineers to virtually walk-through a scanned building (like in a first-person video game)
- Calculate plug-load wattage, and place individual loads from appliances, office equipment, and lights into their respective physical locations within the 3-D model
For a week in November and another in February, my colleagues and I put RAPMOD to the test by comparing it to our usual auditing methods. We conducted tests on a relatively accessible UC Berkeley academic building, which did not have any unusual thermal or electric loads. My colleague and I collected data using a thermal imaging camera, a laser distance measurer, a psychrometer, a wattmeter, a light meter, a headlamp, an iPad, and a notebook. The members of UC Berkeley team used one of their three RAPMOD prototypes.
The Manual Energy Audit Process
My colleague and I spent hours each day measuring room dimensions, plug loads, light levels, temperatures, humidity, and more. Scientists from LBNL measured window U-values. I drew diagrams of individual rooms and noted the locations of computers, televisions, and small appliances. I also noticed a surprising number of room-conditioning devices such as space heaters and fans, which generally contribute to large plug loads. I even found, photographed, and documented one desk equipped with two portable heaters, two portable fans, and an operable window. I took thermal and regular photographs of windows, walls, energy-suspicious features, and refrigerators in graduate student caves and undergraduate classrooms. I noted light levels and locations of measurement while navigating many cluttered Professors’ offices. After all our testing, my colleagues and I also spent time labeling photos, scanning notes, and building databases and models.
It has become clear to us that the RAPMOD is able to complete a model of a building in a fraction of the time it takes engineers to collect data and create a model.
The Future with RAPMOD’s Energy Audit Process
While we still need to trudge around the building, the UC team is close to immediately mapping thermal images on all surfaces of the 3D model the RAPMOD creates. When this new technology is released to the public, cash-strapped building owners and facility engineers will be confidently saying things like,
- “These are, by far, the five leakiest windows in the building. Let’s replace those this year.”
- “There is a small chilled water leak above Room 708. Let’s fix that this week.”
- “Between Bob’s small refrigerator, two heaters, and two fans, he costs us more on electricity than anybody else. Can someone please show him how to open the window?”
See how easy reducing energy costs may be in the future? Luckily for future engineering interns, graduate students, and energy auditors, it will definitely be much easier with RAPMOD. The first RAPMOD weighed around 80 lbs. They are now onto the third prototype, which weighs about 30 lbs.
RAPMOD does not replace an engineer’s instincts or skills – it aids them. As someone who has been on more roofs and in more attics and mechanical rooms than the average person, I can attest to the common knowledge that most buildings constantly waste tremendous amounts of energy and money. By improving building data collection and presentation, energy auditors, building owners, and facilities staff can better find the best investments for energy savings, thermal comfort, and overall economy.