Tuesday, October 09, 2007

Solar Decathlon: pregame show

Gandolf (my parrot) and I went down to the National Mall to check out the Solar Decathlon setup. We've gone together to every show so far. The 2002 show was her first major public outing. I've got a couple groups to show around next weekend when the houses are open and I wanted a preview to prepare myself. Sorry, I didn't take the camera this time. Next weekend, I promise.

There seems to be less diversity in design than in other years. It's all pretty much a box with south facing solar panels on the roof. The differences should be more clear on the inside.

Texas has some artwork on the sides and some plastic panels covering it. I saw a few flapping up in the wind. I couldn't quite figure out why so I asked a young lady on break. The short answer is that they're there for aesthetic purposes. Some are clear and some are opaque and they're arranged in an artistic manner, but they're real purpose is just to keep the rain off the real art.
Texas also stands out in that their hard hats are shaped like stetsons.

A couple of the houses have vertical planters stuck to the southern exposure. They're dirt and peat in a plastic housing which is turned vertically so the plants stick out the side. One has an elaborate system welded together to hold their trays in a rack with a big plastic grey water tank mounted near the top to water them. Grey water is used water sans-sewage. Stuff from the sink and shower, but not the toilet.

It looks like all the houses are using evacuated tubing for their hot water. These are replacements for the old fashioned pipes in a black box that I grew up with. They're supposed to be arranged with one end higher than the other so that convection currents convey the heat to the top and into the water pipe. The first year some of the schools had to start covering theirs or taking it apart because they were getting so much hot water. One school this year covered their southern exposure with these pipes. They have enough to power a turbine, it seems. But they installed them horizontally so I think they'll have trouble getting the heat to the correct end.
Having had time to think about this I think I know what's going on. One school had what appeared to be a hot tub as part of the design. Maybe that's this school.

Besides ingenuity in energy savings the students must be creative in design for transport. One school put their panels in wooden frames to make them easier to put up and take down. The rest of the schools are assembling theirs on site. You may notice on this house the shadow that these boxes cast. Some of the boxes act as awnings over the southern windows. During the summer time when the sun is high (you can reach right up and touch the sky) the shadow covers the windows completely. But in the winter they provide nearly no shade so the sun shines in to make the most of the winter sun.

The Germans have an all glass southern exposure and nearly no awning. I thought they were gonna cook in there. But they have folding doors with screens on them that can be opened and closed to provide as much or as little light as possible.

The Solar Decathlon officially opens on October 12 and runs through the 20th. It's located near the Smithsonian Metro stop at the Mall exit. They're open for tours 10:00 AM - 5:00 PM on weekends and only until 3:00 PM on weekdays. If you find yourself near there after dark they typically have plenty of solar lighting making it an attractive place even at night.

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