Construction trailers are typically built with cheap materials, no insulation and rigid surfaces. They're considered temporary. We move them from one job to the next, and we hold onto them for 30 years. So their lifespan can be as long as the buildings we construct.
Last winter, we held Green Advantage training at a jobsite in Louisville, Kentucky. It was one of those outrageously cold days. The meeting was held inside the jobsite trailer, and though indoors, our team wore their coats, hats and gloves. Vice President of High Performance and Sustainable Construction Susan Heinking took notice.
"It was so cold, people were having a hard time concentrating. If it was affecting their ability to learn that day, imagine how that environment impacted their ability to do their daily jobs - not to mention their health."
Susan Heinking, Vice President, High Performance and Sustainable Construction
If we were going to proceed with this big idea, we had to do it the right way. This wasn't just a prototype. It needed to be practical for our jobsites. That meant it needed to incorporate the right technology to make our people efficient and to be cost competitive with our current fleet.
To plan our Net Zero trailer, we turned to the expertise of our Integrated Construction Services (ICS) team. Together, the team would collaborate on a design that maximized the high-performance and sustainable systems and products, construction techniques and technology, while considering the costs and quality of the end product.
We also tapped the knowledge of our trade partners to provide suggestions regarding materials and methods that would improve performance and keep costs down.
The first step in creating the trailer was to determine the energy load that needed to be offset. The trailer should support 12 people, including their computers, cell phones and other necessary office equipment, such as large monitors. Lights, hot water (tankless water heater), a refrigerator and a microwave were also factored into the equation.
The result: conservatively, we would need to generate 34.71 kwh per day.
Once we had that baseline, we could determine how many photovoltaic panels would be required. Based on a "worst day" scenario, we would get a maximum of 4.5 hours of sunlight a day in the winter.
We knew the numbers, but we weren't finding the right mix of solutions to make the math work. After multiple adjustments, we were about to give up on our goal of Net Zero.
Then, we hit on the right combination:
27 SunPower® E-Series Commercial Solar Panels x 327 watts each = 37.7 kwh per day.
That's enough to generate 108.7 percent of our power daily, making the trailer Net Positive.
The same system and phone app also control the low-consumption lighting. Our strategic placement of smaller LED lighting fixtures (2x2) in areas with more daylight and larger fixtures (2x4) in larger, darker work areas is enhanced by occupancy and daylight sensors.
In addition, the lights can be reconfigured in the future without rewiring. While these features are commonly used in regular buildings, they have never been considered for use in "temporary" trailers.
An opportunity to test technology's limits
It was important to us that the Net Zero trailer be constructed in a sustainable way, and we were committed to a paperless process. We typically create 3D models to both estimate and build our projects. In doing so, installers in the field reference digital plans on centrally-placed screens and handheld tablets instead of paper plans.
Microsoft's HoloLens mixed reality headset is taking paperless to the next level by allowing us to transpose the design over the real environment. So far, we've used it to visualize, problem-solve and confirm installations.
"The HoloLens has been used for installation in a test environment, and we wanted to try using it on a real project. The small project size of the Net Zero trailer and safety of building inside a warehouse allowed us to push the limits of this new technology on a portion of the construction."
Jennifer Suerth, Vice President of Technical Services
After building our framing model for the trailer in BIM, we then loaded it in the HoloLens. Our tradespeople were able to virtually lay out our frames and piping on the trailer base, which essentially eliminated the need for measuring.
We further employed the HoloLens as construction continued to give us "x-ray vision." As the walls and floors closed, we were still able to virtually see through them with the HoloLens so we knew where wires run and studs were placed, as well as other critical elements hidden behind the walls, floor and ceiling. If modifications needed to be made during construction or need to be made in the future, the HoloLens helped us know exactly where to look, cut and correct, saving both time and money.
Watch how we used the HoloLens.
Watch a time lapse of the Net Zero trailer construction.
Bringing it all together
Nine months after our initial conversation about the power strip, GreenBuild contacted us about displaying the trailer at their conference, and we were ready. We spent the next 3 weeks planning, followed by 7 weeks building it. Our self perform team constructed it in our own warehouse, which provided a safer and cleaner environment and prevented potential weather impacts.
The Net Zero trailer is now serving its second jobsite. How well is it meeting the needs of our team?
"When someone enters the Net Zero trailer for the first time, their typical reaction is 'Wow!'," explained the Assistant Superintendent on the Buffalo Grove High School project.
"After working in it for a couple months, I can tell you the wow factor lasts. As someone who likes to be healthy, it's easier to bring good food choices from home and the stand-up workstation gives us a great alternative. Having the natural light really does improve your mood and your productivity. Plus, it just feels good knowing that you're helping the environment."