The University of Minnesota’s Solar Decathlon team‘s handout to visitors to the DOE Solar Decathlon, which opens Thursday on the Mall in Washington, DC, (which I had a chance to visit earlier today) is subtitled “A New Tradition”. Their ICON Solar House hopefully is just that, a representation and sign of “a new tradition” that will help create a prosperous climate-friendly future for America and Americans.
One of the great problems of the Solar Decathlon is that there are reasons to be enamoured with and enthusiastic about all of the competitors, their homes, their philosophy of design/development, and the technologies that they have applied. Without a doubt, a quick visit highlighted reasons for enthusiasm about ICON and the people behind it.
First off, it is a beautiful sight (inside and out) from the clean, semi-traditional lines, the coloring, to the strong statement of solar paneling signaling that (at least for today) this is something different.
“The public can look at our house and see one they identify with. It’s a house that anyone could live in with things that go in a normal home, not the EPCOT Center,” ICON team member John Quinnell noted.
When it comes to technology, the Minnesota team has a ‘home grown’ desiccant system for dehumidifying the air which reduces the air conditioning burden. (The University of Maryland entry in the 2007 Decathlon used a desiccant system in a very aesthetic way. The ICON team decided to maximize efficiency, although their system (awaiting student patent applications, by the way) seems to have some quite interesting decorative potential. My thought: put the mixing area (clear) piping with some LED lighting to create a ‘fountain’ effect.)
Elsewhere, the technology more closely linked to the aesthetic. ICON has two types of PV panels, traditional, roof-mounted PV panels and dual-sided (bifacial) translucent panels. These panels, with a boosting of production by 30% over traditional panels (manufacturer’s claims), provide privacy outside the building, a ‘wall’ that allows through some light while reducing wind exposure for the entry area.
Considering the lovely Minnesota winters, maxing out with R-70 insulation in ceilings and R-50 in the walls is the sort of path that provides serious efficiency. (By the way, that R-50 might actually understate the full efficiency: the walls are staggered (to eliminate bridging loses) 2 by 2×4 structures with closed-cell insulation (rate this as 8 inches by 6+ R per inch: 48R+ with an additional layer of rigid insulation (another R-7, if I recall correctly) sandwiched within …)
This heavy insulation provides another path of combining technology with aesthetics. Heavily insulated walls can sweat, with the potential for interesting (can we say, very troublesome) problems. First off, rather than a “wall”, there is a rain screen (those beautiful red stripes), which allows airflow to help take moisture away from the house, and a high quality membrane behind it. Highly effective while highly attractive.
ICON provides an excellent example of challenges faced by, essentially, all of the competitors:
First, how to design their homes for year-round conditions in their home area while preparing for the competition environment in the unpredictable October weather of Washington, DC? That creates challenges and opportunities for each team. The Minnesota team, with the Icon House, faced the challenge of being so far north, requiring a different angle for the solar pv plus the challenges of hot summers. Thus, the design to enable effective pv placement and overhangs to cut summer heat gain. However, designing for Minnesota doesn’t mean designed well to compete at the Solar Decathlon which, of course, occurs in Washington, DC.
There is that minor little problem that drilling and digging aren’t exactly encouraged on The National Mall. For example, ICON’s ‘shed’ represents a utility closet that might, more rationally, be in a basement. Many of the houses use geothermal systems — since no drilling on the Mall, lots of large tanks.
No matter how they place in the competition, this observer believes that the ICON team has much to be proud of …