U.S. Department of Energy Solar Decathlon




Teams at Decathlon Village
 Photo: Stefano Paltera/U.S. Department of Energy Solar Decathlon

I have looked over a couple of my recent posts about the U.S. Department of Energy Solar Decathlon, and feel that some clarification is in order.  While my blog entries focus just on a few aspects of the houses that were particularly attractive, even “subjective” contests like Market Appeal were judged according to clearly defined parameters in a very analytical fashion.

For the Solar Decathlon, collegiate teams design and build energy-efficient houses powered by the sun. These teams spend almost two years creating houses to compete in the 10 contests of the Solar Decathlon. Each house should:

• Be affordable, attractive, and easy to live in
• Maintain comfortable and healthy indoor environmental conditions
• Supply energy to household appliances for cooking, cleaning, and entertainment
• Provide adequate hot water
• Produce as much or more energy than it consumes

Each team built its house for a target client of its choosing. The Market Appeal Jury of which I was a part evaluated the responsiveness of the house design to the characteristics and requirements of the target client. The criteria that we considered were:

• Livability - Does the design offer a safe, functional, convenient, comfortable, and enjoyable place to live? Does it feature intuitive house controls? Does it meet the unique needs and desires of the target client?
• Marketability - Does the house have curb appeal, interior appeal, and quality craftsmanship? How well do its sustainability features and strategies contribute to its marketability? Does the house offer potential homebuyers within the target market a good value?
• Buildability - Would the construction documents enable a contractor to generate an accurate construction cost estimate and then construct the building as the design team intended it to be built? Could the house's materials and equipment be immediately adopted and built in the private sector?

Solar Decathlon 2013 - A Tribute to Trees

Austria - Toward Media Center

Austria - Toward Deck

Team Austria, which was the overall winner for the 2013 Solar Decathlon, also took second prize in the  Market Appeal competition.  The inspiration for and central design element of this beautiful house was the tree, which has special meaning in Austria. About half of the country’s surface area is heavily forested, and a long history of sustainable forestry assures continued availability of this important natural resource. As the team explains, Austria’s plentiful forests have “for millennia provided environ­mental protection against severe climate conditions and natural disasters, indispensable energy sources and habitats for diverse wildlife, as well as an especially valued, lightweight, renewable resource for building construc­tion. The use of wood as a primary construction material is further­more CO2-neutral and beneficially impacts indoor climate.”

We loved the interplay between the clean, minimalistic design of this house and the warm ambience created by its extensive use of wood.  The craftsmanship in this small gem of a house (a mere 639 sq ft., not counting the mechanical room) was exquisite.  The indoor and outdoor spaces form a single harmonious whole with large sliding glass panels that completely disappear when open (they are concealed inside of the cabinets that line the walls).

This prototype for a pre-fabricated house is designed in modules that fit into standard shipping containers.  The team explained that their design follows the organization of a tree’s main components: the floor-to-ground connections that form the sound “root” foun­dation, the main service core that metaphorically comprises the systemic “trunk” of the house, the structural framework that “bran­ches” out to carry the building envelope, and the changeable textile façade layers that act as protective “foliage” when needed. 

The house and its furnishings are const­ructed almost entirely of domestic wood products.  Both affordability and environmental sustainability are maximized by using the whole tree, including the typically wasted bark, wood chippings and shavings.  For instance, the walls of the bedroom and bathroom are specially-treated bark, and the dining chairs are made of compressed wood chips.  

The team also used outdoor textiles in an innovative and elegant way, creating a passive solar mechanism that mimics the effect of deciduous trees. The whole house, including the outdoor space, is surrounded by a textile façade layer consisting of curtains made of white camo cloth combined with retractable horizontal shading devices. The system minimizes solar gain during the summer months, allowing diffuse daylight to reach the interior and creating a delightful dappled effect similar to sunlight filtering through a tree canopy. The vertical and horizontal textile layers can be fully retracted in winter to maximize solar gain.   

Austria - Deck with Curtains Partially Opened

For Additional Information on the U.S. Department of Energy's Solar Decathlon 2013 Visit the Web Site: Solar Decathlon 2013

Photos by: Jason Flakes/U.S. Department of Energy Solar Decathlon

Solar Decathlon 2013 - Viva Las Vegas!

I was honored to recently serve on the Market Appeal jury for the U.S. Department of Energy Solar Decathlon for a second time. The Decathlon challenges collegiate teams to design, build and operate sustainable solar-powered homes that are beautiful, comfortable, and affordable. All 19 houses were net-zero energy or better in the measured competition, and most of them effectively addressed a number of sustainability issues.

My colleagues and I awarded first place to Team Las Vegas’ entry, DesertSol, an eloquent architectural response to the Mojave Desert climate. The architecture creates a sense of place, celebrates the beauty of a unique ecosystem and emphasizes the importance of an increasingly scarce resource, water. The team defined their central inspiration as a commitment to demonstrate the residents’ relationship with water as well as conserving water in many different ways. The focus on water is particularly appropriate, since Las Vegas was originally founded on the site of natural springs that dried up in merely 50 years due to overdrawing, and there’s danger of repeating history by overdrawing the area’s current water reserve in Lake Mead.

The spatial organization and open plan of this compact, 754 square foot home make it seem much larger than it actually is, and it beautifully combines sustainable design and luxurious amenities.

The layout and finishes of the bathroom make it feel like an elegant, rejuvenating spa. Panels of shimmer glass tiles in the shower and behind the custom sink evoke waterfalls.

A particularly striking feature is the central entry, a space framed between the private and public parts of the house. The entry overlooks what is supposed to be a water feature but was actually more effective than originally planned in emphasizing the vital importance of that element. The team envisioned “a shallow pool of water with a bubbling center, reminiscent of the springs, designed to collect the precious four inches of precipitation each year and store the rainwater in a cistern.” But because there was no rain to fill the cachement system, the house centers around an arroyo (dry creek bed).

The rainwater cachement system was to be used, together with grey-water, to provide any water needed for landscape irrigation. But not much water would be required because the team used native desert plants that require virtually no watering once their roots are established. The plumbing fixtures and the appliances all help save water.

The Mojave is a harsh environment, the exceptional dryness, the intense contrast of sunlight and deep shadows have a profound impact, and the team’s material selection responds to these challenges positively by choosing natural, durable materials that age well in the desert. The silver-gray wood (recycled fencing) and rusted metal of the exterior reference the ghost towns of western lore. The connection between the indoor and outdoor spaces is emphasized by the use of the exterior wood on the walls of the entryway.

Movable perforated steel screens provide privacy for the bedroom and shade in the summer. The pattern evokes light filtering through the leaves of mesquite trees.

For Additional Information on the U.S. Department of Energy's Solar Decathlon 2013 Visit the Web Site: Solar Decathlon 2013

Photos by: Jason Flakes/U.S. Department of Energy Solar Decathlon