Photovoltaics Solar The dish on the Solar Decathlon Within only one week, 19 collegiate teams had to build their technically-advanced, solar- powered, energy-efficient houses to wow judges and the public at this year’s US Department of Energy’s (DOE’s) Solar Decathlon. The unassembled homes began arriving at the West Potomac Park of the National Mall in Washington, DC, at 11 p.m. on September 13. From then on it was a to finish construction and compete in a gauntlet of 10 events to test the designs.

t was the fifth iteration of the popular biennial ability. Four contests – comfort zone (ability to main- event on US soil, which drew collegiate teams tain narrow temperature and humidity ranges), hot Ifrom around the world to design, build and show- water, appliances and energy balance (ability to pro- case solar-powered homes on the country’s so-called duce as much energy as used or even more) – were “front yard”. With its location near the Capitol, the measured with sensors. Entertainment features of event drew an international crowd and was conveni- each house were measured with sensors and juried. ent for US policymakers and other government Each contest was worth 100 points, with a total of ­officials to­visit. 1,000 points available. This year’s competitors hailed from five countries The homes ranged from the eclectic, like CHIP on four continents. It was the first time teams from (Compact Hyper-Insulated Prototype), made by the ­, China and New Zealand’s Victoria University Sci-Arc/Caltech team, to more conventional designs, of Wellington, which came in third, participated in the like that of Perdue University’s INhome. CHIP used a Decathlon. Other competitors included: The University unique “Outsulation”, recycled denim insulation cov- of Maryland, which ultimately won; Purdue University, ered in vinyl sheets, wrapped with steel cables in a Indiana, which came in second; Appalachian State, diamond pattern. It resembled a large quilted pillow. North Carolina, which won the People’s Choice Award; The inside was no less radical. The only walls in CHIP Middlebury College, Vermont; Ohio State; Parsons NS housed the bathroom. The home’s features included Stevens, New Jersey and New York; SCI-Arc/Caltech, sensors that turned on the entertainment center California; Team Florida, etc. when someone sat on the couch. The team designed Some teams were composed of students from just it for young professionals in California and to meet one college or university, like the team from Appalachi- Los Angeles‘ Small Lot Ordinance. an State College. Others consisted of numerous uni- On the other hand, INhome could have passed for versities that chose to work together. “We encourage a home in most US suburbs. “The home was really in- teams to get together with different universities,” said spired by suburban mid-western design. As well as DOE’s Solar Decathlon Director Richard King. Such trying to make a home that would fit into a normal teams can build off member schools’ strengths in de- neighbourhood and make it sustainable and energy signing their house. efficient. We have a lot of natural daylight, a lot of nat- The houses were designed with PV arrays theoret- ural ventilation. We tried to make everything in this Left picture: Team ically capable of providing enough for all their energy home something that‘s readily available to any con- Florida’s FLex House, needs. Beyond that the teams focused on reducing en- sumer,” Matt Hebdon, a structural engineering stu- Team New Jersey’s ENJOY ergy use within the houses, through their choice of in- dent at Perdue. “Aside from [the biowall] everything House and Perdue’s sulation, appliances, solar thermal and passive solar you can get here is from Lowe’s or Home Depot [i.e., INhome (f.l.t.r.)during the design and other features more. The houses had to US home improvement stores]. And the purpose of last day of construction; stay within budget and perform in 10 contests, some that is that anyone can take our ideas and implement right picture: Visitors juried, some measured. them. Not only someone who‘s building a new home, touring Perdue’s INhome. The five juried contests were in architecture, mar- but someone who lives in an existing home who Photos (5):Chris Meehan ket appeal, engineering, communications and afford- wants to upgrade or remodel,” he explained.

130 Sun & Wind Energy 11/2011 The dish on the Solar Decathlon Team Belgium’s (Ghent University’s) E-Cube also Previous events had no cost limit, despite limit- tested the boundaries of what’s traditionally thought ing the size of the homes to 1,000 square feet of liv- of as a home. “We want people to be able to construct able space. The winner of the 2009 Solar Decathlon, their own house and therefore we designed the house Team Germany from the Technische Universität Darm- as a do-it-yourself building kit,” said Project Architect stadt, benefitted from not having a cost restriction. Toon Vermeir. “So you can compare it to a piece of fur- They built a house with a 19 kW PV array (a typical so- niture you buy at Ikea. You get a manual, you have all lar array for a US home ranges from 2 to 5 kW) and an the different components and then you can construct estimated cost of US$ 800,000. The team had also the entire house yourself,” he said. E-Cube’s Inter- won the 2007 event with a different design. locking, prefabricated insulated panels, window and “We wanted to put a halt to this escalating cost, door panels, were all the same size and comprised so we put an affordability contest in this year,” King both the exterior and interior of the home. It allowed explained. Under the contest, teams could spend up the homeowner to configure it how they wanted and to US$ 250,000 on the house and its construction be- for future expansion as needed. The two-floor interior fore being fined – costs external to the house itself was similarly designed. According to Vermeir, “the were not included. Teams that spent more on the structure is a cheap pallet racking system you can find house were docked points on a sliding scale. When in warehouses. They are very cheap because they are costs reached the border of US$ 600,000 the teams mass produced and they are very easy to assemble.” lost all 100 points. According to King, material dona- Teams also brought other innovations to the con- tions, like PV and appliances were considered part of test. Appalachian State University of North Carolina’s the affordability challenge – teams said they chose to Solar Homestead, an innovation in itself, consisted of forgo such donations when they realized they would one main building for living in and a series of smaller exceed their budget. out-buildings that were under its “Great Porch” – a The affordability contest brought more parity to canopy covered with an 8.2 kW bifacial PV array. The the decathlon, King asserted. “It‘s actually made the structure and design, though cozy as a home, could contest smarter. It‘s been a challenge and been a de- be repurposed as a visitors’ center for a park. The light.” At first he feared that the cost restrictions team patented three technologies used in the home, would limit the innovation power of the entries, but including its method for using phase-change materi- the homes remained unique and diverse. al to store thermal energy, a technology other teams used in other ways. Emerging competition leaders The University of Maryland’s WaterShed house featured a patent-pending liquid desiccant waterfall No team really dominated the competition. But three (LDW), which reduces the amount of energy required teams, Ohio State with its enCORE house, Maryland to cool the home in humid areas like in Maryland. and Perdue were the top three through most of the “The wall reduces the amount of humidity in the air competition. However, in the waning days, Ohio State and reduces the load on your air conditioner,” said stumbled and New Zealand’s Voctoria University Joey Ijjas, a Master of Architecture Student at the Uni- picked up steam. Maryland was in its fourth Solar De- versity of Maryland. cathlon. Ohio had previously competed in the event, but it was the first time for Perdue and New Zealand. Affordable solar homes It’s INhome design fared well among its peers. Maryland’s WaterShed home was inspired by the The newest contest, the affordability contest, likely imperiled Chesapeake Watershed. As such, in addi- Left picture: Fellow decathletes had a large influence on this year’s designs. It’s also tion to being solar powered, it incorporated water re- visit Maryland‘s WaterShed.; among the most difficult to asses. “We often thought use from showers, sinks and rainwater that would right picture: DOE officials about putting costs in but it’s very argumentative and otherwise end up in a sewer. Greywater collected talks with members of the CHIP its tough to do,” said DOE’s King. ­onsite was remediated by native plants before return- team.

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Solar Decathlon Final Scores ing to the ecosystem. The de- 2002. The site was steps from a metro stop and on sign also included three distinct one of the most heavily traveled parts of the National Place Team Score out of 1,000 units a living area, a rest/work Mall. It was sandwiched between the Smithsonian 1 Maryland 951.151 area and a bathroom. museums in eyeshot of the Capitol and close to the 2 Purdue 931.390 It was the second time the White House. People working in the area could visit 3 New Zealand 919.058 Ohio team participated. “I par- the houses and learn about solar and energy efficien- 4 Middlebury College 914.809 ticipated in the previous event cy during a lunch break. It was the location that teams 5 Ohio State 903.938 and we learned a ton actually. It had designed their homes for. Teams had already 6 SCI-Arc/Caltech 899.490 mostly pertains to the construc- started promoting the location of the event and used 7 Illinois 875.715 tion,” said project engineer Matt the prominent location to help attract project spon- 8 Tennessee 859.132 O‘Kelly. “We were much smarter sors and donors. 9 Massachusetts 856.351 about the racking of the PV sys- When the park service and DOE announced that 10 Canada 836.423 tem. It also inspired some of the the event needed a new home, which could have 11 Florida Int’l 833.159 decisions in the house, such as been anywhere in the US, Chicago, Illinois, New York 12 Appalachian State* 832.499 the core.” Hence the home’s City, ect., teams banded together – a hallmark of the 13 Parsons NS Stevens 828.816 name was enCORE. competitive yet friendly contest – to keep the compe- 14 Tidewater Virginia 774.910 The Ohio team used the core tition on the National Mall. “There was a pretty good 15 Team China 765.471 model to concentrate mechani- cohesion between the entire group of teams when we 16 Team Belgium 709.843 cal features in one part of the found out we were kicked off the Mall,” Joey Ijjas from 17 Team New York 677.356 house. “Last time it spread out Team Maryland said. “Most teams really did a good 18 Team New Jersey 669.352 all over the place. We had plumb- job of contacting their Senators and local Represent- 19 Team Florida 619.006 *Winner of People’s Choice Award ing connections, we had hun- atives to get as many people mobilized as possible. dreds of control wires across That was nice because there was a lot of cohesion to these breaks, up in the insula- that.” tion. We said never again. So now we have remote in Elected officials like Menendez sent letters to the and outputs for the control center. And every breaker Obama Administration and the park service request- is monitored so we can check everything every- ing to keep it on the Mall. Menendez said he was glad where,” O’Kelly said. The Ohio team was also the on- to work with the students, and that he had worked out ly team to use thin-film CdTe PV, which were made by with the administration in order to forge “a sensible First Solar. solution so that the competition can be in a place of prominence that it deserves on the National Mall.” Solar Decathlon experiences It took more than a month of uncertainty until they growing pains won, sort of: West Potomac Park is about a mile away from the former location on the Mall, two miles from Visitors congregate under Since the first event in the US in 2002, the competi- the Capitol and has no nearby stops for public trans- Appalachian’s Great Porch. tion has garnered international interest and is quick- portation. The organizers arranged a free shuttle serv- ly growing into an international ice to and from the event site to facilitate visitors. It’s family of events. “Solar Decathlon also less than two miles from the Ronald ­Reagan is growing. Last year the first Euro- Washington National Airport, jets scream overhead as pean decathlon was held in Ma- they take off and land. The site is frequented by tour drid, Spain. It was a huge success,” busses, but gets nowhere near the natural foot traffic King said. Madrid will host another the event saw at its former location. Solar Decathlon Europe again in From the beginning, teams were a bit wary about 2012. And in 2013, China will host the site. They were concerned about the number of it’s first Solar Decathlon. people coming through. But while there may have Even as the Solar Decathlon been less foot traffic in terms of passersby than in grows internationally it’s previous years, the event saw more visitors than ever into difficulties in the US. “It‘s not before. The organizers count how many people visit long ago that we were wondering, the homes. “There were 357,000 visitors this year as if the competition would be here in opposed to 307,000 in 2009,” King said. “There were Washington at the National Mall,” several times when the sun was out, that the place said New Jersey Senator Robert was mobbed, you had to wait half an hour for some Menendez, a Democrat, during the houses.” Still, the location was a bit more difficult for event’s opening ceremony. the teams, because distance to food, hotels, trans- Earlier this year the teams had portation and taxis had grown. the rug – or in this case the ground, Where the US event will take place in 2013 is literarily – pulled out from under still up in the air. “We‘re putting a request for pro- them. The US National Park Serv- posals on the street to take bids from anywhere. ice, which maintains the National Washington, DC, can put a bid in that should come Mall, determined that the event out in ­October – to find a new home for us,” King was too damaging to the park, de- said. spite having hosted the event since Chris Meehan

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