Solar Decathlon 2009

It was a great Columbus Day weekend in Washington DC, and Solar Decathlon was making waves on the news… Well, actually it did not. Not even bigger green sites and blogs covered this truly green event. Probably there were much more important things happening in our capital – like Obama’s newly “adopted” dogs :).

So I’ll let the big guys do their things, while I tell you about the event, which so many people waited 2+ years for, and worked so hard to make it happen – ladies and gentlemen – Solar Decathlon 2009!

Solar Decathlon 2009 at the Mall in Washington, DC

This was our first Solar Decathlon, but certainly not the last. Since we were sponsors of Team Boston Solar Home, most of my coverage will be focused on it. However, there were many great solar homes this year: Team California and Team Germany were battling for first place (you can see Team Germany solar home in the picture above – a black house, second from the right).

As I wandered through the Mall, looking at these homes and being hesitant to stand in line to see very similar interior set-ups, my main focus was on the outside. Solar technologies, energy efficiency and exterior design were my main concern, as these factors make a true solar home, while the inside can always be remodeled.

Team Boston Solar Home:

As a future architecture student, and a “construction worker” now, I look at these houses with a slightly different perspective than most people. For me, the ease of construction, highest energy efficiency and reasonable cost are the most important things, followed by a nice design. Unfortunately, many of the innovative approaches used for this competition are not accessible to the masses, and remain to be a privilege for the most extravagant home buyers with deep pockets. While I have no problem with it in general, in my opinion, the purpose of a Solar Decathlon is to move innovative green building technologies into the mass housing market, so that such technologies would actually make a major difference in improving the environment and reducing CO2 emissions.

Team Boston solar home at the Solar Village in Washington DC

It is expected of all these homes to be super insulated and have solar PV panels on their roofs. I was interested in innovative new approaches at achieving maximum effect (energy efficiency or energy generation) using the least expensive methods. In this regard, the Boston Solar home has (had) great potential, if not for the massive glass array on the northern side of the house. All these windows and doors will let all the heat escape in the winter, which makes it that much less efficient. This is a fixable situation however – just remove most windows and put a wall there 🙂

Despite potential heat loss, the liquid-filled glass units on the southern side of the house will collect tremendous amounts of solar heat and store it, making it much easier to heat this house. Find out more about these liquid-filled solar thermal windows and wall panels.

In addition to solar thermal wall panels, Boston solar home has about 6.4 KW solar pv system on the roof and a solar thermal hot water heater, for heating and domestic use. There are many other new and innovative design features used by BAC (Boston Architectural College) and Tufts University students in the construction of this home – too many to list here. You may check out the project’s website –

Team Spain solar home:

Another solar home that attracted my attention was the one build by Team Spain (which for some reason was doing VERY poorly in this competition).

Team Spain solar home: Rotating solar panels array and solar PV cells built into walls.

Apparently, these bi-pv cells are very good at capturing indirect sunlight and help the house generate the most electricity it possibly can.

Team Spain used a very interesting (in my opinion) approach at capturing ALL available solar energy with their powerful solar PV array. This roof mounted array can rotate at the center, following the sun going across the sky, thus always keeping the most efficient angle of the PV panel to the sun. It is basically a gigantic solar tracking system, which is however complicated and expensive to implement, making this house not as competitive in terms of costs and ease of building.

Additionally, the glass walls of this home have integrated solar PV cells, which capture even more solar energy. It is a good idea, but an overkill in my opinion, as the roof mounted solar system should be more than sufficient and, unless they used “dummy” cells on east, west and north sides of the house, it is a waste of solar capacity, as the sun will barely or never hit those solar cells.

Building-integrated solar panels mounted on glass walls.

Cornell University Solar Home:

Another interesting design, which for some reason reminded me of the Water World movie was a solar home built by Cornell University students. It featured three round “rooms” connected to each other, and a large solar PV system, which for some reason was mounted flat to the ground.

Cornell University solar home - round steel frame with flat, roof mounted solar panels.

It may not be the best designed house (in terms of competition rankings), and round rooms make it ever more difficult to build, but the steel frame and a VERY cool vintage design made it very attractive. As I was writing this, Cornell’s solar home was in 6th overall place, with a few more contests to go. You can view current team rankings here:

As a side note, as of Oct. 13th, Team Boston solar home is in 12th position and Team Spain is in 18th place, while 1st place belongs to Team California.

Let the best solar house win!

The Solar Decathlon will continue for another week or so, and there are a lot of contests left in which either team can pull forward dramatically. Therefore, I will not even try to predict the winner. All houses presented in the Solar Village this year were very well designed and built, and the green building technologies used in them will in the (hopefully) near future migrate into traditional construction markets and help home and building owners reduce the overall energy use and make our environment better. This competition is also an inspiration for the new wave of architects who will be literally building our future homes and infrastructure, and as you can see, they all have great ideas. I will continue to cover the Solar Decathlon 2009 in future posts, and soon you will be able to review the IB flat roof installation which we did on the Curio Home – look forward to seeing it soon on our cool roofing blog.

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