You Mean This is a Competition?

The more I see of the houses in the Solar Decathlon, the more I realize that this is not a competition with a level playing field.  Or to put it another way, every one of the twenty entries makes such a unique and independent contribution to the further deployment of solar power that they could be considered winners even before the judging starts.

Today I spent some time with David Siguenza of the Universidad Politecnica de Madrid, learning about the unusual structure that is Team Spain's entry in the event.  One of the first buildings a visitor sees after emerging from the Smithsonian Metro station, the 'Black and White House' appears as a flattened cube wearing a house-size mortar board at a jaunty angle. 

The 'mortar board' is really an inverted pyramid pivoting on a ball-and-socket joint a couple of feet above the house's flat roof, with a PV array covering its entire upper surface.  Nine times a day the pyramid moves to align itself with the sun's changing position, so as to maximize the efficiency of the panels' monocrystalline cells.  It's a perilous-looking arrangement, one that's easy to visualize taking off in a high wind like the farmhouse in 'The Wizard of Oz', but that contingency has been considered by the designers.  The structure is stressed to accommodate winds up to 120 mph, and at 90 mph it automatically levels itself and is secured by hydraulic jacks.

The walls of the Black and White House also contribute to its electrical output.  Floor-to-ceiling panels of polycrystalline silicon cells provide extra power, optimized for cloudy days, and shading for interior spaces.  And the theme of following the sun is taken up here too, since the panels pivot at the house’s corners to follow the progress of the sun in the sky.  It’s hardly surprising that the designers of the Black and White House have applied for a total of five patents for the various systems that run it.

The aggregate output of the roof- and wall-based PV systems is 14.9 kW, exceeding the needs of the house by a factor of six.  This is augmented by a solar hot water system for domestic hot water and radiant floor heating. 

So how are we – or, more realistically, the juries – supposed to judge between a house like this and that of Rice University, intended for low-to-middle-income use in housing projects?  By design, that house deploys only as much PV as is needed to balance its expected energy consumption.  Or the Puerto Rican entry, designed to mimic traditional Caribbean building styles while being energy-efficient and affordable?  Or Wisconsin-Milwaukee’s Meltwater house, in which an emphasis was placed on using locally obtained waste materials?

The short answer is that they will, but the final scores the juries assign cannot possibly reflect the disparate values applied by teams to their efforts.  In effect, the twenty teams took off in twenty different directions – Iowa State to design a home specially for seniors, Ontario to craft a solution for higher northern latitudes, Louisiana-Lafayette to reflect Cajun traditions and customs in its design.  For each team, a unique concept. 

As for Team Spain, the students don’t regard the surplus energy produced by their ‘pyramid’ as excessive, more as an amount of power waiting for a user.  This could be a plug-in hybrid car, or a doubling in size of the family living in the house (for which purpose the house is of modular design, and can be expanded outwards or upwards).  In fact, the pyramid with its support structure can be used without a house beneath it;  it could be used as a power-generating carport, or as a mini-generator for several buildings, or as a mobile power source for field operations.  Applications, in short, far beyond the scope of the Solar Decathlon.

Since no scoring system could possibly level the playing field for all these players, we feel constrained to regard the ‘competition’ element of the Solar Decathlon as little more than an incentive for the teams to apply their creativity to the best possible ends.  Looking around the houses in the solar village (and if you haven’t yet made the journey to Washington to experience them, don’t delay much longer!), we’d say it’s done an excellent job of that.

About one hundred of the reasons why you shouldn't wait to visit the Solar Decathlon:  Crowds lining up today to visit (left to right) the Team California, Puerto Rico, and Illinois solar houses.