Solar Decathlon team explores whether a net-positive house is possible in middle TN
By Alisha Newton
Dr. Ralph Bruce is alone in a small dining room in a private club in Nashville. Oil paintings line the walls — scenes from the Harpeth River and coastal Maine. The March sky outside is gray and overcast. Bruce drags a table to the center of the room, places a large foamcore model of a house, and begins to arrange the pieces. He nervously fiddles with the angled roof sections as he waits for guests to arrive.
With his white beard and wire-rimmed glasses, Bruce looks like some kind of academic godfather. Himself a professor of electrical engineering at Vanderbilt University, he has invited students and professors from Vanderbilt and Middle Tennessee State universities; local contractors and engineers; and project managers from Habitat for Humanity.
They soon begin to filter into the room. There’s Stefan in his blue company polo, “E3 Innovate” embroidered in neon green. He stands and chats with a couple of men from Habitat, John and Chip. As Vanderbilt undergraduate students arrive, they gather in a circle. Derek is reserved and unassuming; Danny has long hair, a faded magenta; Tucker is warm and quick to smile; and Annie is a fast-talking New Yorker with piercing green eyes. After everyone else is seated, Elizabeth, a soft-spoken blonde graduating from MTSU in May, arrives out of breath, and her mentor, Dr. Janis Brickey, waves in greeting from across the room, her angular glasses slipping down her nose.
Eventually there are eighteen people seated in front of gleaming white plates and heavy glass goblets. These people are more accustomed to working in construction sites and engineering and design labs than to sitting at white tablecloths with two forks, but these professors, students, and professionals are all part of the same team: Team Tennessee.
The foamcore model that Bruce painstakingly displayed represents a year and a half of meetings, builds, proposals, and designs for the sixth national Solar Decathlon competition. Sponsored by the Department of Energy, this high-risk, high-reward competition gives teams from top universities 20 months to design and build energy-efficient homes that are at once affordable and attractive to consumers. The teams that compete in Solar Decathlon are required to raise hundreds of thousands of dollars in order to design and build their houses, but the technology featured in Solar Decathlon houses is typically 10 years ahead of code adoption and 5 years ahead of market, so college students are finding themselves on the leading edge of the clean energy field.
Next to the model is a stack of brochures titled “Harmony House: Redefining the future of housing.” Harmony House was a massive and idealistic effort on the part of these eighteen (and many others) to influence home construction practices at the intersection of affordability and sustainability. However, the mood of the luncheon feels more like forced cheerfulness than celebration. Severely short on funds, the team is dissolving, and the house may never be built.
TEAM TENNESSEE BEGAN with a bold idea. In Spring 2013, a small group of students in the School of Engineering at Vanderbilt asked, “Does the University have what it takes to compete in Solar Decathlon?” They tried to answer their own question for an electrical engineering course, and in doing so, started on the path toward changing the status quo of home-building in Tennessee.
Solar Decathlon has been held every two years since 2002, first in Washington, D.C., and now in the sunny city of Irvine, California. Styled as the Olympics of housing, it requires know-how in architecture, engineering, construction, and communications. Since the first competition, more than 17,000 college students have competed on 112 teams to build the house that best represents the triple threat of affordability, sleek design, and energy efficiency — specifically, it must produce as much energy as it consumes.
While not all of successful Solar Decathlon houses could mesh with mainstream neighborhoods, they are starting conversations about solar energy all over the world. For example, the “Y Container” in Shanghai, China, is made from six retired shipping containers, an example of the up-and-coming “cargotecture.” Closer to home, the “Living Light” house — now sited at the Children’s Museum of Oak Ridge in Tennessee — had more than 50,000 visitors from 2011 to 2014. Thirty-two other houses from past competitions are currently open for tours, continuing to educate the public about clean energy.
Faced with this tall order, in the following fall semester, the students formed an organization with the intent of applying for Solar Decathlon. That October, a handful of students scouted and networked at the 2013 competition in California. The team then reached out to Middle Tennessee State University, which has programs in construction management and interior design with accreditation options that are not available at Vanderbilt.
In addition to MTSU, the team also recruited Habitat for Humanity of Greater Nashville, a non-profit organization. The conception of Harmony House as both sustainable and affordable meshed well with Habitat’s mission to provide quality housing for low-income families in Tennessee. Senior Vice President of Construction for Habitat, Chip Wilson, said that Harmony House would act as an “incubator” for sustainable building practices, especially “active” or more expensive ones like the solar panels and energy modeling. In Tennessee, a 5-kilowatt array costs about 12 thousand dollars after tax rebates, and if a panel quits working, how would a low-income family afford to replace it? “We are always trying to push the limits of sustainability in our houses, but we don’t experiment on the families who buy homes,” said Habitat project manager John Reed. Harmony House would allow for a kind of “experimentation” that is typically cost-prohibitive to Habitat.
Finally, the students and faculty also worked with E3 Innovate, a Nashville-based company. Stefan Peter-Contesse, a “Building Scientist” and project manager for E3, said that they made initial design recommendations for Harmony House and later employed the popular modeling software REM/Rate to approximate the home’s energy usage.
Two months later, a team of nine people — including the founding members, project managers, and principal investigators from Vanderbilt and MTSU — submitted their 30-page proposal to the DOE, outlining their qualifications and their idea for the competition.
On Valentine’s Day in 2014, they got the news that they were accepted to the competition alongside teams from Stanford University, Clemson University, University of Florida, and Yale University, as well as several international universities. One the faculty advisors said, “I thought it could happen, but there was some shock when it actually did happen.”
Derek Phillips presided over the Solar Decathlon student organization at Vanderbilt this year. He said of the process, “It was highly competitive, and we were happy to get accepted. We know of some teams that didn’t get in, because we searched Facebook for ‘Solar Decathlon 2015’ and saw teams that had a page but didn’t end up in the competition.” There’s no way to know how many teams apply each year, but only 20 teams are selected, with each team representing one to four universities.
THE INITIAL EXCITEMENT quickly gave way to tedium with undertones of anxiety. Suddenly, on top of their busy course loads, students also had the additional chore of completing required DOE documentation.
Project manager Danny McClanahan speaks to students at a Solar Decathlon meeting.
One of the project managers, Tiffany Silverstein, recalled this experience: “[The DOE would] have these massive deliverables due, and we’d spend weeks and weeks working on them, and still be cramming at the last minute to get things done. They had very high expectations.”
Collaboration with MTSU provided many of the hard skills necessary for the project. Once when they needed a model, MTSU students built one and Vanderbilt students picked it up the next day in Nashville. Students even spent part of their winter break working in the model studio on MTSU’s campus.
The three groups — Vanderbilt, MTSU, and Habitat — met periodically to design the floor plan, and they all worked together on several Habitat builds. “They teach average Joes how to build a house, and that was exactly what we needed,” said Phillips.
By this time, several of the founding members had graduated from Vanderbilt (one is now studying Nuclear & Radiological Engineering at Georgia Tech, and another stayed for the graduate program in electrical engineering). However, the student organization would eventually accumulate a LISTSERV of about 200 members, which were divided into engineering, communications, or fundraising committees.
Students Marie Armbruster and Tucker Kirven led the engineering committee. Armbruster, who studies chemical engineering, was on her elementary school’s recycling team. She speaks precisely and thoughtfully, and as self-described logical person, she says, “I don’t know how people can deny the fact that we can’t use more resources than we have. We can’t just keep burning fossil fuels.” She first heard about the project at an organization interest fair at the beginning of her first year at Vanderbilt. “At first I thought, ‘They’re building an entire house?’ It seemed really outlandish at the time, but I immediately became involved.”
As Kirven starts talking, he brushes his mop of blonde hair out of his eyes and grins. A student of computer engineering, he speaks energetically about energy modeling for the house. As an independent-study project in Spring 2015, he wanted to design a wall-mounted touchscreen device, inspired by one made by Schneider Electric. This thermostat monitors all of the energy usage, costs, and if applicable, solar-energy production in the house, and it can also remotely control appliances and heating and air conditioning systems. Kirven’s prototype would adapt the technology of Schneider’s $200 device to work with an old smartphone, showing that real-time energy monitoring can be affordable.
THE DESIGN CONCEPT of the house was centered around Nashville and “Southern living.” With input from MTSU students, they homed in on the 19th-century dogtrot style, which would split the house into open cooking and dining areas, and a more private section with two bedrooms. The house would be wrapped with a wide covered front porch and an outdoor garden. The name ‘Harmony House’ alludes to the marriage of sustainability with Tennessee’s historic roots: “Just as notes combine in musical harmony, these two influences fuse synergistically.”
Last summer, Elizabeth Kurtz completed an internship along with eleven other students to work on the floor plans and interior design for the house. “‘Should I be allowed to design a house?’,” she laughed, recalling how she felt at the time. As the project gained momentum, students like Kurtz felt the sense of exhilaration upon realizing that they were doing important work, the kind that matters to the world beyond the college campus and that so many students yearn for.
She worked with Garrett Rome, a graduate student in Vanderbilt’s Department of Civil and Environmental Engineering, to make 3D models in Revit, and renderings in Photoshop. She said it was eye-opening to see which concerns were important to the engineers compared to the designers. “The biggest impact [of the project] on me was the interdisciplinary teamwork: working with people from different backgrounds — the engineers, designers, and architects — and having to balance all of those perspectives.”
Kurtz’s mentor throughout the process was Janis Brickey, known to her students as “Dr. B.” As an undergraduate, Brickey studied passive solar systems at Virginia Tech, and as a professor at MTSU, she guided the design process as students both universities contributed their ideas. Kurtz said that Brickey would call to check in with her throughout her summer internship: “One time I started crying over the phone to her,” she said. At the time, Kurtz was emotionally invested in the project, and stressed by its demands.
Kurtz is originally from Nashville, and she is passionate about the city’s unique aesthetic. “What makes me the most upset is when I see developers come in who don’t know Nashville very well, tearing down these beautiful old homes or Nashville institutions to build high-rise developments that all look the same,” she said. For reasons related to both design and sustainability, she loves repurposed buildings, like Werthan Lofts in Germantown. This residence retains the brick and high ceilings from its first life as a flour-bag factory.
So when designing the house, she was never focused on the competition, but on the family she envisioned: “When I came up with the concept for the house, I [focused on] the idea that this house is for a family and it has to be functional as a gathering place. … A lot of houses built for Solar Decathlon in the past have been über-modern boxes, but I knew that when the house came back to Tennessee, it would be in a neighborhood in East Nashville, and I wanted the façade to fit in.”
The collaboration with Habitat played a critical role in design planning. “We had this idea that Habitat could take our design and reproduce it; to apply low-cost heating and cooling solutions that would be easy to implement but provide efficiency gains,” said Phillips. A home that demonstrated that sustainable building technology is feasible in middle Tennessee would be an important step toward clean-energy homes. To this end, Harmony House was designed to have a white roof to reflect sunlight, with elevated bifacial solar panels that are 20 percent more efficient than regular solar panels, and the engineers planned to incorporate an energy/heat recovery ventilation system that saves energy by relieving the HVAC system.
The porch, as represented in the team’s final renderings.
WHILE STUDENTS DEBATED design details, Ralph Bruce was thinking about the larger field of sustainable technology. As one of the principal investigators of the project, Bruce joked to me that his job as the principal investigator was just to do all of the paperwork. Indeed, all of the free space on his desk was covered with messy stacks of paper.
As an engineer, he sees Solar Decathlon as a testing ground. “It is estimated that it takes roughly 30 years for a new technology to become part of the standard practice. It took at least 20 years for the cell phone to become common,” he said. “But how can you pick winners early on? You have to have enough potential winners out there to be able to pick, and that’s what the DOE is doing with Solar Decathlon: identifying practices and technologies that could successfully improve the way we build houses.”
As a professor, Bruce saw Harmony House as more than just an engineering project. It was, as he said, “an effort to educate students in all ramifications associated with developing the build community and integrating technologies that decrease carbon and increase renewable energy.” Working on the house was pushing students into the real world: they were shaking hands with people who have spent their professional lives thinking about engineering, innovation, and clean energy.
Through heating, cooking, and managing waste, residential and commercial buildings emit 12 percent of the greenhouse gases produced by economic sectors in the U.S., an increase of about one percent since 1990. However, through the need for electricity to power lights, air conditioning, and appliances, buildings eat up an even larger share of the pie, up to 34 percent — the equivalent of 2250 million metric tons of carbon dioxide. This is an increase of 28 percent since 1990.
Most of that electricity is generated by burning high-carbon fossil fuels, but photovoltaics are part of the effort to change the basic energy equation of residential buildings. Since Solar Decathlon began in 2002, the cost to install residential solar panels has dropped from $9 per watt to $5 per watt in 2011 (based on a 5-kilowatt array).
It’s true that less than one percent of energy produced in the U.S. comes from photovoltaics, and in Tennessee, the total energy produced by residential panels is about 3.2 megawatts, enough to power only 525 of the state’s 2.8 million homes. Solar power seems like a drop in the ocean of electricity, but the sector is growing rapidly — and throughout it all, Solar Decathlon has been on the leading edge of this growth.
PLANNING AND PREPARING for Solar Decathlon came with many constraints. For one, MTSU, located in Murfreesboro, is a forty-minute drive southeast of Nashville, posing an inconvenience when it came to design meetings. The house itself had to include ramps for ADA accessibility, and it had to be able to be shipped precisely 2000 miles across the continent and assembled in nine days. “We ran into the problem of designing what we wanted versus designing for the competition,” said Phillips.
Their solution was to take a modular approach — a trend in the construction industry that makes houses more accessible and affordable. “The wall modules would be in a more finished state, such that they could be erected on-site without as much need for interior finishing,” said Bruce. These sections would be trucked separately to their destination, and then bolted together.
So the obstacle that proved insurmountable was not the design, but the funding. The team struggled to find university money that was not already specifically designated for another purpose, and as an official Vanderbilt student organization, they were not allowed to maintain their own bank account (they could take direct donations through calls to a specific phone number at The Calling Center at Vanderbilt).
Otherwise, Phillips told me, they would have used Kickstarter or similar fundraising platforms. “The Dean of Engineering was truly excited about our project,” he said, citing the fact that some other universities fund their Solar Decathlon teams. “But in the end, they just could not support us.”
Some students worked almost exclusively on meeting with the Office of Corporate Relations at Vanderbilt to establish sponsorships, writing grants, and making calls to potential giving partners, but their efforts proved unsuccessful — they were short two or three hundred thousand dollars, according to Bruce.
The end of the project came in two stages. First, the team withdrew from the competition. In an email sent on January 26, 2015, the president Derek Phillips wrote: “We will continue to move forward with the planning and construction of the home with a slightly extended timeline. …We are excited to break free from the many rules and time constraints we previously had to work under, and our greater emphasis on the community will make the project stronger as a whole.”
This was the “first death,” according to Kirven. “At first I was shocked, but then I realized that it actually put us in a better position. We were only losing the name ‘Solar Decathlon.’ Being in the competition did not merit the cost of having to drive the entire house across the country — we were compromising on design and suitability for Nashville.”
But less than a month later, the decision was made to dissolve the project entirely. “That feeling was much worse. It’s not like it fell apart or disbanded because it was disorganized. It was like someone shot it, and it died,” said Kirven.
Armbruster expressed similar frustration: “Someone could pick up materials and start building this house right now using our designs.”
The students wanted to have a local impact locally, but their challenge is the challenge faced by the build community in middle Tennessee: Even if they had successfully built a beautiful conceptual house for the competition, could they really have changed the way low-income housing is designed and constructed?
After the project ended, Bruce realized that Tennessee Valley Authority (TVA) restricts solar power with their policy of dual-metering: Electric companies like Nashville Electric Services (NES) buy homeowner-generated solar power for 15 cents per kilowatt hour, but there is a limit to the amount of energy residents can sell. “This is a major hurdle associated with how NES or TVA allows you to engage or connect to their grid,” said Bruce. Overall, dual-metering would make the goal of a net-positive home difficult for Habitat to replicate affordably. In addition, the DOE defines “affordability” as less than $250,000, which was the median new home sale price in 2010, while Habitat’s houses are constructed for just $60,000.
Phillips is more optimistic. He expects that electricity costs in middle Tennessee will rise, and that construction companies will be forced to focus on energy efficiency. “Today, to put a solar panel on your house makes a statement [about environmentalism], but as panels become cheaper and more efficient, it could be commonplace in just a few years.”
IN THE WAKE of the project, all of the students I met felt that their participation was worth the professional skills and connections they gained, especially in the fields of solar power and sustainable design. Having a real-world application for their skills made students learn quickly, and Derek Phillips has taken an internship for summer 2015 with the local engineering firm Smith Seckman Reid, Inc., the same company that designed the Commons, College Halls, and Featheringill Hall on Vanderbilt’s campus. One of the project managers, Marie Armbruster, will be researching photovoltaics at an Air Force base in New Mexico.
Some of the take-aways are less tangible: collaboration and communication became essential when the project was at its peak. “There was such a cohesion during design meetings. They knew that in order to go on, they needed to work together,” said Janis Brickey, expressing a feeling common among the professors that led the project. It was also exciting and intimidating to work on a “real” project, said Elizabeth Kurtz: “Students were trusted with power.” In the process of stepping out of their comfort zones, they gained incredible knowledge.
Chip Wilson from Habitat thinks that Vanderbilt student and faculty deserve recognition. “What happened here is not a failure by any means. It’s part of scientific research. It’s part of a learning process.”
The day the team met for lunch, there was talk of Sterling Ranch near Denver, Colorado. Over the next 20 years, this project aims to build a town entirely powered by solar energy, including 12 thousand homes, schools, a shopping center, and even a church. Started by a Vanderbilt graduate, it will house Vanderbilt researchers in every field from engineering to education. Inquiring into Sterling Ranch, I received an email stating, “This thoughtfully designed community is committed to fostering, furthering and promoting the extraordinary quality of life inherent in Colorado’s spirit.” Some of the Vanderbilt students who worked on Harmony House plan to apply to work at Sterling Ranch.
Wherever the future takes them, those eighteen people will remember with mixed feelings of fondness and frustration the project that brought them together. After meeting with the harsh reality of funding — and on a larger scale, resistance to renewable energy in the Southeast — they came together one last time for lunch in a room with white tablecloths. Here they said their goodbyes to the idea that inspired them, sustained them, and empowered them all.
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