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PRI's Environmental News Magazine

Solar Decathlon

Air Date: Week of August 24, 2007

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The contender, shining in the sun. (courtesy Bruce Gellerman)

Host Bruce Gellerman visits MIT where students are putting the finishing touches on a solar-sufficient home. It’s the school’s entry in this year’s Solar Decathlon, sponsored by the Department of Energy. The homes in the contest must be built with off-the shelf technology that run entirely on solar energy.

Transcript

GELLERMAN: This week in Washington, well actually not much happened. It’s late August after all. Congress is on vacation, the President is on vacation, even our own Washington correspondent Jeff Young is on vacation. So, at least on this program you’ll hear no news this week out of Washington. Instead here’s a story closer to home about some people working hard to get to Washington.

[DRILL SOUNDS]

GELLERMAN: There’s a fenced in parking lot on the campus of the Massachusetts Institute of Technology that looks like a scene out of the TV series MASH. There’s a metal Quansat hut, a sign pointing the way to distant places, and in the air a sense of improv and irreverence. In fact on the MIT campus here in Cambridge they call this place MASH. It stands for Modern All Solar House.

MIT is one of 20 teams of college and universities students competing in the Department of Energy’s Solar Decathlon. It challenges students to construct houses powered entirely by the sun. It means squeezing every watt of energy from the solar homes they built. And like the show MASH rules are, well, creatively flexible.

DECOLA: My name is Jonah DeCola and I’m a construction manager and I’ve been brought in to help the Solar Decathlon team sort out all the chaos of this new technology.

GELLERMAN: Are you an MIT student?

DECOLA: No, I’m not. I’m a freelance construction manager.

GELLERMAN: You’re a ringer!

DECOLA: I’m a ringer, yes.


L-R) Jonah DeCola, Hugo Lukacs, and Kurt Keville working on their decathlon entry.

GELLERMAN: Is that allowed by the rules?

DECOLA: For support, absolutely. Sure. To consult with experts.

GELLERMAN: Have you ever built anything like this house?

DECOLA: Green affordable housing has been a passion of mine. I’ve been doing some projects in Boston for a number of years. So, bringing this technology to market is the key. And so how is that transition going to happen without folks being able to familiarize themselves with the products so that it has a seamless transition. What we’re facing as far as the future green building, in practical, terms is the ability to bring this technology to market.

[SAWING SOUNDS]

GELLERMAN: The Solar Decathlon requires teams to use off-the-shelf products in new and creative ways. The idea: to demonstrate solar energy is technically and economically feasible today.

[DRILL SOUNDS]

GELLERMAN: MIT students have been building their house since spring. It’s almost done but almost as soon as it’s finished they’ll have to take it apart, truck it to Washington DC and re-assemble it on the National Mall where the 20 solar decathlon homes will be judged in 10 contests just like the Olympic decathlon.

The categories include architecture, livability, comfort, appliances, and hot water production. The solar self-sufficient homes even have to power an electric car using energy produced only by the house.

Kurt Keville, the principle investigator for MIT’s entry in the Solar Decathlon details the rules:

KEVILLE: So, the competition favors a levalized energy analysis for your locale.

GELLERMAN: You sound like somebody who’s from MIT.

KEVILLE: Ok, sorry. You have to build a 800 square foot house that’s completely off grid. You have to power a car as well as all of your appliances: washer, dryer, stove etc., off of any energy that you generate from the sun.

GELLERMAN: Ok, so let’s take a tour.

KEVILLE: Sure.

[TRAFFIC SOUNDS]

KEVILLE: Ok, we’re walking up a flight of stairs, we’re simulating where we’re going to be on the mall with stilts. On the mall we’re not allowed to dig into the ground so we’re building it on diamond pier pin foundations.

GELLERMAN: Now, I noticed that you’re not using that white stuff that they usually put on the outside of houses before they put on the finish. You’ve got this green guard. What is that?

KEVILLE: That’s right. This is a new style of house wrap that actually wicks the water, if you look on the inside of this material it actually wicks the water from the top to the bottom. It’s got this nice sort of plastic capillary system that brings the water down. This will keep our OSB, our plywood good and dry.

GELLERMAN: OSB?

KEVILLE: OSB, yeah it’s the plywood that’s on the outside of our structural insulated panels. I think you can see on that gap there, a sip is two pieces of plywood separated by six, eight or ten inches of polystyrene, of styrofoam. And it turns out that’s a really good way to not only get high thermal R values but it’s also quite light. It’s very easy to work with. I mean all these walls were put up with basically two man lifts and we just clicked them together like legos.

GELLERMAN: And you’re going to unclick them to get them to Washington.

KEVILLE: That’s right, yeah. That’s another thing we would do differently. We use screws in this house rather than nails because we’re going to have to disassemble it, reassemble it and then one more disassemble-reassemble, at the end of the competition.

GELLERMAN: Now how efficient is this house going to be?

KEVILLE: Well, that’s where we think we’re going to make our bones. We have a really good, you can see how the light is falling right now, we have a really good way to capture day lighting so we won’t have to turn the house lights on at all during the day. We also have a fairly innovative cross flow of air. We got windows down low to bring in cold air on the cold side of the house and windows up high to blow it out. We’ve got skylights and clear story windows up in our eaves here to carry the air through and that will give us some good natural convection.


The contender, shining in the sun. (courtesy Bruce Gellerman)

GELLERMAN: Now, this is New England. It gets cold.

KEVILLE: That’s right.

GELLERMAN: Now, those walls look like standard sized walls. Anything special in the walls?

KEVILLE: These sips are rated quite highly. We uh, we can specify the thickness of a sip. Our roof, the structurally insulated panels on the roof are a couple more inches thick than our walls. We think we’re going to have plenty of heat in the house so our walls are six inches thick and our roof is ten inches.

GELLERMAN: What’s the R value then in the walls?

KEVILLE: Twenty-seven for the walls. Now that’s pretty good. We also have really, really high-end triple pane krypton gas separated windows. And those are R values about 15 to 17.

GELLERMAN: Wow

KEVILLE: Yeah.

GELLERMAN: What about this big window? It looks like, I don’t know, it must be ten feet by four feet, five feet high?

KEVILLE: That’s right. We’re calling that our warm light wall.

GELLERMAN: But it looks unlike any window I’ve ever seen.

KEVILLE: That’s right. It’s an innovative tile design. Each one of those tiles has a couple pints of water in it as well as a thin layer of aerogel.

GELLERMAN: Aerogel?

KEVILLE: Aerogel, yeah. Aerogel is a very very thermally insulated material developed at Cabot Corporation. Very light, easy to handle, and it lets light go through it. That was one of our key things here, is to let the visible spectrum come through the wall and it will take all the infrared and the UV out. So you’ve got a very good thermal barrier on the exterior of the house and I’m very interested to see what this house does in January. We’ve done calculations so that this house will be net energy positive year round. And January is going to be our big test I think.

GELLERMAN: Net energy positive meaning that it will generate more energy than it needs and it will put it back into the grid.

KEVILLE: That’s right. In January we’ll have to dial down our usage but I think we’re going to be wildly net positive this month and next.

GELLERMAN: What is it going to cost you to build this house?

KEVILLE: Well, we are tracking both our real costs and our retail costs. We’ve gotten quite a bit of financial sponsorship with this. So, to that extent this is probably a $250,000 house, which is a lot for 800 square feet, but we’re generating probably twice the amount of electricity you would generate if you were actually building a 800 square foot house.

GELLERMAN: One bedroom.

KEVILLE: One bedroom. One office. This section here is a long kitchen/dining room section. That wall there is the bathroom and utility room in the very back.

GELLERMAN: What’s the prize?

KEVILLE: Bragging rights. The history of this competition is there’ve been two previous competitions, alternating years, odd years and Colorado’s won both of them. Colorado is far and a way the team to beat.

GELLERMAN: Do you have any spies out in Colorado watching what they’re doing?

KEVILLE: No, kind of the opposite we have people coming back to graduate school at MIT that have participated in previous years on other teams and that kind of experience is invaluable to us.

GELLERMAN: MIT’s Kurt Keville. In a sense you could be a winner in the Solar Decathlon because many of the construction materials and methods demonstrated in the contest could be used to build an energy efficient home in your future. This year’s Solar Decathlon promises to be close.

[MUSIC: Johnny Mandel/Bob James. Theme from M.A.S.H. from the soundtrack to the film M.A.S.H.]

GELLERMAN: There’s only so much innovation you can jam into one small house. But by one measure MIT’s entry is unique. It’s measured in Smoots. The Smoot is named for Oliver Smoot, MIT class of ’62. As a freshman his fraternity brothers initiated him by turning him head over heals to measure a bridge connecting MIT to Boston. One Smoot equals 5 feet 7 inches. Making MIT’s MASH, Modern All Solar House, about 47 square Smoots, give or take a square here.

For pictures and more information about the Solar Decathlon check out our Web site: loe dot org.

 

Links

Solar Decathlon Website

MIT's Solar Decathlon Website

 

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