Students compete to design solar homes

Full-size 'Solar Decathlon' entries populate Washington's Mall Oct. 12-19.

If the predictions of 1950s futurists had come true, we'd be whizzing to work in hovercrafts as domestic robots cleaned our prefab domes. While such idealistic prophesies are often tempered by time, that hasn't kept academics and inventors from creating bold visions about the home of tomorrow.

That's exactly what brought 20 teams from universities across the country and around the world to Washington, D.C., this week. And rather than presenting Styrofoam renderings or computer images of their visions, they're trucking full-size working models of their homes of the future in a bid to win the third Solar Decathlon, sponsored by the US Department of Energy and taking place on the National Mall.

Beginning Oct. 12 and continuing through the 19th, the 20 solar-powered homes will be viewed by movers and shakers from the world of sustainable housing as well as members of the public.

"These aren't futuristic pods or anything like that," says James Bickford, student leader of the Santa Clara (Calif.) University team. "We just integrated some of the best and most efficient products out there into a house that people would actually want to live in."

The first decathlon was held in 2002 and another in 2005 with the intention to hold the decathlon every two years thereafter. The DOE gives each student team $100,000 to build a house that relies exclusively on solar power and uses products already on the market.

A team of experts will judge the homes in 10 categories (hence, "decathlon"), including communications (how well they explain the technology to the public), architecture, and getting around (how far an electric car charged by the house's solar panels can go). The teams also cook dinner for the judges using energy-efficient appliances. Drying towels is another challenge.

The DOE's goals for the competition are twofold: to arrive at a consensus on what the best "green" design practices are by 2015, and to have a house produce electricity for

10 cents a kilowatt hour – competitive with public utilities. Along the way, the DOE hopes to encourage tomorrow's engineers, architects, and homeowners.

The team from the Massachusetts Institute of Technology (MIT), a first-time competitor, began working on their house, Solar 7, back in February 2006 with the hope of unseating two-time victor University of Colorado. MIT students spent countless hours almost every weeknight and weekend to develop their entry.

Today, their home stands beside other entries on Washington's Mall. Solar 7 is an 800-square-foot cedar clapboard home. The interior is made from bamboo, a material that grows four times faster than wood. It has a bedroom, kitchen, and bathroom with sliding doors that can subdivide the space to make it more versatile. Despite its small size (set by competition rules), Solar 7 has all the labor-saving devices: washer, dryer, oven, refrigerator, TV, computer, and dishwasher.

The walls are made of "wheat board" (ground-up wheat stubble), which made the house "smell like a barn" before the board was fireproofed, says Corey Fucetola, MIT's project manager. The black kitchen countertop is made from paper and resin, and the south-facing wall out of structural insulated panels that create a "warm wall."

Products must be on the market

The insulated panels are set to go on the market this week, and the MIT team thinks they may give them the winning edge. The one-foot-thick panels are made of two sheets of opaque plastic with water sandwiched between them. The panels' exteriors are coated with Aerogel, which transmits sunlight through to the water to heat the interior of the house without letting heat escape.

In the summer, an awning mounted over the warm wall keeps sunlight from hitting it and heating the house.

Unlike the pie-in-the-sky futures of the past, the technology in these homes is not only achievable, proponents say, but urgently needed as a way to deal with global warming and energy shortages.

Skeptics are in­­vited to visit Greg Sachs's house at the US Merchant Marine Academy in New York. It was the New York Institute of Technology's entry to the 2005 Solar Decathlon.

Mr. Sachs, a professor at the merchant marine academy and founder of its alternative-power program, helped design aspects of both the NYIT and USMMA houses two years ago. Part of his reward was getting to keep the house and see how it works for everyday living.

"Something I teach my students," Sachs says by phone, "is that we've been through the Industrial Age and the Information Age. Now we're entering the Age of Energy. This is going to be the defining thing for our generation: How can we power our lives and homes with something other than fossil fuels?" The decathlon hints at how homes may function.

Result: a negative electric bill

Sachs has a negative electric bill. His home produces more than he uses, so he sells the excess back to the power company. That could be the reality for anyone living in any of the homes in Washington's "solar village." Some came from as far away as California and Colorado, Spain and Germany to be in the competition.

All the homes are powered exclusively by solar and designed to operate off the electric grid. But they must produce enough power to juice up an electric car.

This year, Sachs is working with NYIT and MIT (where he's a distance grad student) on their photovoltaic systems.

The MIT students built Solar 7 in a vacant MIT parking lot, hanging up sketches and calculations on the side of a makeshift metal arch. A banner hanging on it reads, "If it exists, it must therefore be possible."

The team lives by its motto, taking existing technology – some of it brand-new – and adapting the energy-efficient products to the typical American home.

"These houses are innovative because they're bringing all these things together – the products, the materials, the engineering, the architecture – into one integrated system that looks and operates pretty much like a normal house," says Santa Clara's Bickford. "It's about finding the best blend of sustainability."

Two factors determine how well the houses will perform, says Kurt Keville, adviser to the MIT project and a researcher at the university. One is the house's load: how much energy the house needs for everyday functions.

In MIT's case, their house features all Energy Star appliances (Energy Star is a government program to promote energy-efficient products) to keep the load down. Other schools will try different tactics, says Keville, which his team won't see until the competition.

The second determinant of a house's self-sufficiency is how much solar energy it can produce. The MIT and NYIT teams have boosted the efficiency of their solar arrays 10 percent by using a new kind of current inverter. Inverters take the DC power generated by the solar cells and convert it to AC.

MIT's 42 solar panels can generate 9 kilowatts of energy per hour in ideal conditions, while the average home in Massachusetts requires only 25 kilowatts per day. The extra wattage is mainly to show the best they can do since it's a "concept" home, says Jim Dunn, MIT's technical adviser.

MIT's team analyzed the winners of the 2002 and 2005 decathlons to help guide their design. They decided that the rainstorms at the 2005 event were less likely than the heat wave at the first decathlon. So the team decided on an efficient solar array and extensive use of passive solar.

While engineering is important, it must be successfully combined with architecture. This was a challenge for SCU, Bick­ford says, since their school has less of an architecture focus than other schools in the competition do. Some of the team's civil engineers had to learn how to become architectural artists and seek the advice of professional architects in the area.

And while the capacities and efficiencies of the homes are more important than aesthetics, the team's architects tried to make the design as attractive as possible. Often the teams' designs include a nod to their university's geographic home: While MIT's exterior cedar siding makes it blend in with many New England homes, SCU's has a "modern mission" feel, a tribute to California's historic mission architecture.

"Every school has a different culture that is really expressed in their house," says Bickford.

While the planning and design for an ecohouse may be right up MIT's alley, the practical concerns proved the most challenging, Dunn says.

One reason the home took so long to build was that many of the obscure products and materials used in the home took months to order and ship to Cambridge.

Another practical issue was the fact that building materials had to withstand a 400-mile truck trip to Washington, D.C. Thus, the team chose to mount the bathroom tiles on a resilient plastic material.

Another part of the competition's challenge came from the fact that the team must include student volunteers with a variety of skill sets. In total, about 60 people have worked on Solar 7 since planning began last year, but the core group was 20, Keville says. One of the most challenging parts of the process was finding students with a background in manual labor and construction.

Home-building priorities changing

One person they found was Samina Ali, a Cambridge resident and environmental studies graduate from Oberlin College in Ohio. She volunteered to help with MIT's house anyway she could. "This is what I want to do as a career – designing and building green homes. I've done carpentry for Habitat for Humanity and other homes before, but this is great experience for me to learn about new products and local materials that are available," she says.

Nick Gayeski, a building technology PhD candidate at MIT, worked on some of the architectural plans for MIT's home even though he didn't have a background in architecture. Part of his interest in participating sprung from his trip to the decathlon in 2002 with Cornell, where he did his undergraduate work. Another incentive for joining the MIT team this year is his interest in pursuing sustainable engineering in the future and perhaps living in such a house himself.

He says the reason zero-energy homes aren't built commercially is not because we lack the ability or technology, but because homes are built with speed and size as the main priorities.

But those priorities are changing as homebuyers want more ecofeatures, says Amy Tighe, a "green" real estate agent and volunteer construction worker at Solar 7, as she labels pieces of cedar siding for reassembly in Washington.

"My friends all ask me where I got my tan and I say, 'I didn't go to the cape; I got in on the job!' " she says, and laughs.