URBANA — Designing a "net zero" solar-powered house is challenging enough without trying to do it in two languages across two continents with a 13-hour time difference.
The latest University of Illinois solar house, dubbed "Etho," is being built in conjunction with a team at Peking University for the first-ever Solar Decathlon China competition in early August.
The house is already under construction in Beijing, and members of the UI team will begin arriving there later this week to start work in earnest.
The Solar Decathlon is a biennial competition sponsored by the U.S. Department of Energy that challenges teams of college students from around the world to design and build energy-efficient, fully solar-powered homes. The United States has hosted five competitions since the inaugural event in 2002, and in 2010, Spain launched a companion European event. China later signed an agreement with the DOE and will host the inaugural Asian contest in Datong, about four hours west of Beijing.
A total of 22 teams from 13 countries have entered the contest. Several teams have international partners, including the UI, which also competed in the U.S. Solar Decathlon in 2007, 2009 and 2011.
So why is the UI team participating in China's event?
Professor Xinlei Wang, faculty adviser to the group, said the Illinois Clean Energy Community Foundation, which provided $150,000 to $200,000 for previous UI efforts, was unable to supply any money this year.
Wang didn't want to discontinue the program but wasn't sure he could raise the full $700,000 project cost without the grant.
Then he was contacted by Peking University, which was looking for an experienced partner to design and build a showcase house for Solar Decathlon China, which he had helped organize. Wang felt the collaboration was "a great opportunity" for the UI students, providing a unique educational and cultural experience and enhancing their future careers.
Teams of students from Urbana and Peking have been collaborating on the project for months, using email and Skype. At the UI, almost 100 students participated in some way, with about 50 key members, Wang said.
This year's modular design incorporates traditional and modern Chinese architecture along with smart-energy technology.
Architectural leader Zak Helmick, who just received a master's degree in architecture from the UI, said the Peking students wanted to include a traditional open-air courtyard, and the final design updated that concept.
The shape of the home is reminiscent of a Chinese house with a single sloped roof, but cut into two pieces connected by a dining room that functions as an enclosed courtyard, Helmick said. A "living wall" of greenery, a skylight, and windows at both ends overlooking two outdoor courtyards connect the room to the outdoors, he said.
With just 1,000 total square feet, the house also has two bedrooms, one bathroom, a living room and a fully equipped, energy-efficient kitchen with laundry facilities. The goal was to make it practical for a young Chinese family while conserving energy, Helmick said.
The materials come from around the world, including structural insulated panels from China, a super-efficient heating and air-conditioning system from the United States, and triple-pane thermal windows with built-in blinds from Germany, "the best-insulated glass in the world," said project manager Kevin Donovan, UI graduate student in architecture and construction management. Long-lasting and durable zinc panels wrap the roof and walls, inside and out, accented by bamboo cladding.
Other features that help make the house a "net zero" energy user: an array of solar panels, extra-thick insulation, a solar water heater and a skylight that functions as a solar panel.
A new "phase-change" material is being used in the drywall and insulation to store heat and cut down on energy use by about 7 percent, students said. During the day, the material absorbs heat and melts, and at night when temperatures cool down, it solidifies and releases the latent heat.
The house also incorporates a new style of magnetic LED lights that can be easily moved along a metal fixture, the first house to use the product, Donovan said.
The team added automated systems that monitor energy use, water consumption, temperature, lighting, humidity, solar radiation, even doors and windows left ajar. It can all be controlled from an iPad, said UI mechanical engineering graduate student Mike Wang, who is leading the engineering team.
"It's pretty much Bill Gates' home on steroids," he said, referring to the Microsoft Corp. co-founder.
The Chinese and UI students collaborated at every step, but not without challenges. The U.S. team ordered many of the materials but had to convert measurements to the metric system and ensure the products were certified by Chinese safety labs. Electric voltages and plumbing standards are also different in China.
The house itself cost about $500,000 to build, covered by business sponsors and other donations, mostly from China, students said. But the price would be closer to $200,000 if more conventional materials were used, such as vinyl siding instead of zinc and bamboo, Mike Wang said.
As building codes get "greener" and more companies begin manufacturing energy-efficient materials, prices will come down, he added.
"This is something that is on the horizon," he said. "The purpose is to demonstrate to the public that this is feasible and in the long run makes sense."
Because Peking University is hosting the event, the team can't take home the trophy, but it will be judged in all 10 categories alongside other entries.
Unlike the three previous models, the 2013 solar house won't be returning to the UI campus. Peking University owns the house, and it will be moved there after the contest in Datong to be used for public education, Wang said.
The team considered building a duplicate here, but money ran short, student Mike Wang said.
This year's sponsors include the Grainger Center for Electric Machines and Electromechanics, the Student Sustainability Committee, MetalTech-USA, JAsolar, Quacent, Unilux, Stalwart Green Global, Whirlpool Corp., Phase Change Energy Solutions, Kohler, Wight & Co., Ovan Energy, Molex, the American Institute of Architects Northeast Illinois, Loxone and the UI's UI College of Business, School of Architecture and departments of Agricultural and Biological Engineering and Civil and Environmental Engineering.
Previous UI solar homes
— 2011 "Re_Home": Designed for rapid assembly after a natural disaster, it finished seventh in the Solar Decathlon and is on display on South Race Street, across from the Yankee Ridge subdivision.
— 2009 Gable Home: This farmhouse-inspired entry, which took second place overall, sits just south of the I Hotel and Conference Center.
— 2007 Element House: After placing ninth in the decathlon, this house spent six years at the Chicago Center for Green Technology but is being moved to the energy farm on the Urbana campus.