A report from the Solar Decathlon

One team will be named the "winner" at the Solar Decathlon. The first two times,
the University of Colorado team has claimed the honors. At the moment, this favorite is far behind and the odds aren't looking so hot that they will get a hat trick. Yet ... yet ... this helps highlight how every single one of the 20 teams has winning concepts, winning innovations, and winning technologies in their entries.

The Colorado entry is named CORE, as the house designed is built around modular core elements (with heating, cooling, water, electrical systems) around which the rest of the house can be built. And the Colorado team has done a magnificent job of incorporating the elements into the design, with radiant tubing providing a partial screening of the kitchen in a functional decorative element.

But, onto making ice from the sun....

The Colorado solar system is 8.8 kilowatts of PV paneling with the solar hot water system underneath the PV paneling (which actually increases the PV's efficacy due to a cooling effect). During the day, the solar thermal water system will be used to heat water for building heating needs. Obviously, heating is most needed at night. Thus, the system builds up a reservoir of heat in the tanks to be released to meet nighttime demands. (In essence, the house's water tanks are used as the equivalent of the ground for geothermal heating systems.)

In summer, however, the CORE heat pump system will reverse the flow. Cooling is required during the day while the system operates more effectively at night. Thus, during summer nights, the solar thermal system on the roof will be utilized to throw off waste heat from the house. The high-efficiency heat pump will exploit this to make encapsulated ice, which will then carry the heating load during the hot daylight hours even though the tank has relatively limited volume.

The CORE's "storage tanks storage tanks also allow optimization of the interaction between building loads and power sources, both from the sun and from the electric utility."

Ice from the sky. Colorado's Solar Decathlon approach to making hot summer days more tolerable.

Comments (9)

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Nice...
written by Preston , October 17, 2007

Cool report straight from the scene...

Sweet
written by Porter , October 17, 2007

Amazing, I wonder how long it will be before everyone is living in a house like this.

sorry to be cynical
written by johnny , October 18, 2007

or how long until anyone can afford one

...
written by Increase PR , October 18, 2007

The problem with such technologies is that there far from being cheap... indeed

Affordability ...
written by A Siegel . , October 18, 2007

All of these houses are 'prototypes', but a key criteria (new) for this Solar Decathlon is whole house affordability at 10 cents / kwh cost of running the house.

The Colorado team says that, in production, a 2100 square foot home would run $280,000, except for land. That is under $140 per square foot, quite affordable in today's construction market. And, well, for that $140 the owners would have basically zero utility costs (thus a savings of $1500 year, which covers what -- $40k of the mortgage cost when tax implications are included?).

Not to mention
written by Jon , October 19, 2007

Not to mention any tax subsidies and breaks from using renewable energy sources.

modular home
written by Celia , October 20, 2007

If these green houses were taken under the wings of modular house companies, more things could be taken care of more quickly. The cost could be cheaper; more people would know about these houses; fiscal advantages could be accessed more easily. I want one quite badly, yet I can't afford one. If a modular home company had one, I would get one. How convienient could that be? I don't know another method of availability.

...
written by Free houses , October 21, 2007

Fantastic! And how much will such house probably cost??

Container Homes & Off-grid can be under
written by David Bushey , October 22, 2007

Please visit myspace.com/green_homes. We are developing floor plans and homes from re-cycled containers using black/gray water waste treatment, then through "air to water" machines in atrium/greenhouses delivering pure drinking water from the clouds. Our team is developing concentrator solar panels along with our existing panels. We have DC current Solar Air conditioning, 100 gallon solar water heaters under $1000. Through our green architect, we can put together a home that is truly "green" and affordable. My friends electric bill this summer for air conditioning was $700 per month.

Dave

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