2009 Solar Decathalon

October 17, 2009 5:20 PM

For the second time in two years a team from Germany has won the US Department of Energy's Solar Decathalon. This year's entry was a cube shaped house entirely covered in 300W and 70W solar panels generating a peak of 11.1kW. The DoE has published a complete product directory of all the subsystems and components used to build each house. Another notable design is the Canadian Team North house designed for optimal solar+insulation performance in high latitude climates.
posted by thewalrus (15 comments total)

Metafilter: a cube shaped house entirely covered in 300W and 70W solar panels

(sorry.)
posted by shammack at 5:40 PM on October 17, 2009

I just hope the Solar Decathalon team doesn't test positive for star-oids.

Ouch.
posted by twoleftfeet at 5:46 PM on October 17, 2009

I suppose you could say it has a modular design.

(works with lots of solar panel modules for a living)
posted by SirOmega at 6:13 PM on October 17, 2009

I like the Team North design, although it has a few things in it that either aren't thought through (that I can tell), or have just been overlooked. Ex.: above the kitchen "densepack" area, they have a "sculptural ceiling" made from "translucent fabric." Combine that with the lack of apparent ventilation over the range, and you are going to get one smelly, rancid kitchen once that fabric gets saturated with airborne grease and cooking smell. Also, it doesn't matter if the material itself is fireproof; once it gets loaded with grease and oil, it'll burn like crazy.

It's the relatively small oversights like that which will make the difference between a livable space and something that becomes obnoxious quickly.
posted by Kadin2048 at 6:43 PM on October 17, 2009

I also wonder at the relative insulation value of a building with three glass walls, even if they are double paned, filled with an inert gas, with a multitude of shade/curtains that can cover them at night. It's supposed to be designed for latitudes north of Edmonton, where winters can be pretty brutal from the end of October to early April.
posted by thewalrus at 6:57 PM on October 17, 2009

For maximum energy production you wouldn't want anything casting shadows on it so it couldn't be too close to anything big, like another house. So, direct sunlight all day, no shade trees and a claustrophobic lack of windows?
posted by podwarrior at 7:04 PM on October 17, 2009

According to their blog, Team North's house is coming to Vancouver for the Olympics - can't wait to see it once it's here.
posted by seawallrunner at 7:17 PM on October 17, 2009

Second place went to the "Gable Home," designed at the University of Illinois.
posted by washburn at 8:09 PM on October 17, 2009

I'm glad to see that PCMs were used in Team North's design, but selling it as a more compact thermal mass doesn't really do the science justice. That's a technology that could really come down in price if we cared about it.
posted by adipocere at 8:12 PM on October 17, 2009

I will admit to more than a little moment of -- FSM help me -- school spirit here. Team California is composed of students from California College of the Arts and Santa Clara University. I'm a second-year law student at SCU and can attest that the university is like a proud auntie about Team California's showing at the Solar Decathlon. We're not only beaming, we're plotzing. We're beaming and plotzing.
posted by bakerina at 9:14 PM on October 17, 2009

podwarrior, I don't think the German house lacks windows -- it just looks that way from the front view. Watch the video, it seems to be very well-lit.
posted by creasy boy at 1:47 AM on October 18, 2009

So, solar experts, how quickly are production costs shrinking? I looked into the costs for that for the German house and one of their main panels seems to cost about $2000 per. One side of the house would add up to about $150,000. Add in the roof and that's about $750,000 in addition to all the other costs of the house.
posted by ursus_comiter at 3:45 AM on October 18, 2009

The cost of PV panels has cone down by a factor of 100 since the 1950s (Nemet 2006, Beyond the learning curve: factors influencing cost reductions in photovoltaics', Energy Policy 34 (2006) 3218-3232) though this was from a high base and it would probably be more instructive to look at the last couple of decades, Oliver and Jackson (Energy Policy 28 (2000) 14, 1011-1021) suggest a reduction in costs of around 80% between the 1970s and late 1990s (£15000/kW to £3000/kW) and this will have continued to fall since as a number of nations (most notably Germany) have been investing heavily in driving up capacity and pushing dynamic efficiency.

Projecting forward, Van Der Zwaan and Rabl suggest that PV costs are unlikely to come down sufficently by 2020 to assist in making a significant contribution to climate change mitigation, (Energy Policy, 32 (2004), 13, 1545-1554) though in a previous paper the pair suggest they might make a signifciant contribution by 2030 (Solar Energy, 74 (2003) 1, 19-31).
posted by biffa at 6:11 AM on October 18, 2009

The German cube house 40 300-Watt panels for the roof, and amorphous photovoltaics for the wall. The cost estimate on the decathlon website for the house is $650k-$850k.
In terms of photovoltaics, it seems like a nice demonstration of a few things -- including amorphous panels to keep production up on cloudier days, and incorporating the panels into the design of the house. But that's a lot of panels, and some of them aren't going to produce much based on their orientation. And podwarrior's right that in most real settings some of the panels are going to be shaded by trees, buildings etc. But all competitions like this are going to be a little artificial, and it is still nice to see what's possible.
I was surprised to read that the house uses phase-change materials in the walls, as I hadn't heard about these in a long time. The idea as I understand it is to find a material that freezes at about room temperature. So during the day the walls use absorbed heat to melt the phase-change material that is presumably well encapsulated and stable. At night the material freezes, giving off the heat absorbed during the day.
posted by Killick at 8:54 AM on October 18, 2009

The german house uses rather lousy $/watt panels, $2000 for a 300W panel at 15% efficiency... You can get good Kyocera 210W panels for $595 a piece these days.
posted by thewalrus at 1:40 PM on October 18, 2009