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Solution of the Month

A Solar Decathlon house shows off the Building Dashboard, an Internet-enabled energy and water monitoring system.

Team California
November 2009

By David Sokol

In October, visitors to the Solar Decathlon strolled 20 student-designed houses on the  National Mall in Washington, DC. They may have been particularly impressed by the work of Team California, a partnership of Santa Clara University and California College of the Arts. Indeed, the result of their collaboration, Refract House, won the Solar Decathlon’s individual architecture competition, and placed third overall.

Solar Decathlon house
Photo © Jim Tetro, U.S. Department of Energy Solar Decathlon
Team California’s Refract House
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Comprising three modules deploying steel angles, moment frames, and bamboo joists, Refract House effects a gently curved shape hugging a central courtyard. The roof supports an uninterrupted 10.8-kilowatt photovoltaic array; it also directs rainwater into a catchment system that, along with graywater from the shower, bathroom sink, and washing machine, is recycled for irrigation. The building boasts almost too many sustainable elements to list, including a rainscreen made of fire-damaged redwood, a series of clerestory windows that maximizes diffuse daylight, exterior waterproofing membrane salvaged from billboards, and recycled-denim insulation.

One of Refract House’s green features helped portray the others in action. The Building Dashboard, an Internet-enabled interface, monitored Refract House’s energy and water consumption in real time.

The Building Dashboard is a product of Lucid Design Group. Ross Ruecker, Team California’s controls and monitoring lead and a recent graduate of Santa Clara’s bachelor’s program in mechanical engineering, was introduced to the five-year-old company serendipitously and helped adapt Refract House to accommodate its technology.

Doing so meant embedding branch current monitors (also known as CTs, current transformers) in Refract House’s circuit breakers. Ruecker likens CTs to doughnuts of copper coil that wrap around outgoing wires, and which produce a magnetic field proportionate to the number of amps running through each circuit. “You then multiply the voltage across the whole circuit breaker by the current of each circuit to get power consumption,” he explains.

Electricians installed 42 CTs according to Team California’s wiring schematic. That total number includes sensors hooked up to Refract House’s photovoltaic array, to account for energy production. To measure water use, team members installed six flow meters: Internal turbines track the volume of water traveling through the corresponding pipe. Analogous to the PV system’s branch current monitor, a gauge also kept track of graywater storage.

All these measurements were sent to a data logger, and Lucid’s software processed that information, stored it in company servers, and posted the interpreted data on the Web. “Doing this with a dedicated service is more efficient,” Ruecker says, “because we don’t have to provide power for a server and interface in Refract House.”

The Building Dashboard displayed net energy and water consumption. “We broke it down by appliances, lighting, the thermal system, and plug loads,” Ruecker says. “It turns out that the thermal system and HVAC blew everything else out of the water. That really opens your eyes to turning down the thermostat, adding some insulation, covering up air leaks. That’s what I like about the system, it makes the homeowner think.” Currently the Building Dashboard costs a premium, and has been installed in far more commercial and institutional buildings than homes. But once Lucid increases its production and brings down the cost to suit the residential market, imaginably Solar Decathlon attendees will rush to this eye-opening, intellectually engaging product.

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