Last year, the U.S. Department of Energy sponsored a Solar Decathlon, an event that pitted 14 teams of architecture and engineering students against each other to see which could design, build, and operate the most energy-efficient and aesthetically designed house powered entirely by solar energy. For two weeks during September and October 2002, the National Mall in Washington, D.C., hosted the “Solar Village,” where the teams’ houses were evaluated by industry experts and toured by the public.
To build the best energy-efficient, solar-powered home, the teams focused not only on design and aesthetics, but also on the building products they would use in their houses. The winning team, from the University of Colorado at Boulder, evaluated potential building products—from framing timbers and foundations to windows and photovoltaic panels—based on nine criteria: low-embodied energy; sustainably harvested; environmentally friendly manufacturing process; recycled; recyclable; value-added; non-toxic; low-VOC; and made in the United States. Each building product had to meet at least three of these criteria.
The Colorado team found that at least one currently available, off-the-shelf building material in almost every category met the requirement. The team also found that these materials are priced comparably to conventional building materials while providing improved efficiency.
To gather solar energy, the students chose photovoltaic panels by AstroPower for the surface of the house’s main roof. A standard AstroPower solar energy system of 24 photovoltaic modules can generate nearly half the power consumed by a typical home, says the company.
SUNTube solar thermal evacuated tubes by Sun Utility Network collected solar heat for the house’s hot water system. In this system, solar energy is gathered, converted to heat, and then transferred to water stored in the tubes.
The Colorado team chose Primalite glazing for the skylights because it reduced the penetration of heat-transmitting solar energy into the structure while allowing visible light wavelengths in to illuminate the space. According to Brian Cross, technical support manager at PolyGal USA, maker of Primalite, the product “will reduce the sun’s near-infrared energy so that the interior of the space is cooler.”
Daylighting played a large part in the Colorado team’s design. To reduce the house’s heat gain, the team speced Heat Mirror insulating glass by Southwall Technologies. “As you increase daylighting, you increase the amount of solar heat gain, and that creates a problem,” says Graig Young, vice president of architectural products worldwide for Southwall.
Other teams found solar technology products to suit their requirements as well. For example, the Crowder College (Mo.) team installed solar cell panels from BP Solar, and the University of Virginia team used photovoltaic panels from ASE Americas.
Over the past four years, the demand for solar panels has increased by 20 percent each year, according to the Department of Energy. “Energy is presently a high-cost item,” says Les Hamasaki, executive vice president and sustainable development planner for Sun Utility Network. Solar energy “is the only source of energy that is provided free.”
Southwall Technologies
Heat Mirror Solar Control 75 insulating glass suspends a clear, coated film between two panes of glass to reduce heat gain by more than 50 percent and to block 99.5 percent of ultraviolet radiation and reduce interior fading. Heat Mirror controls noise transmission, says the company, and is available in bronze, blue, green, clear, and gray. 650.962.9111. www.southwall.com.
Phenix Biocomposites
Using renewable, sustainable, and recycled resources, the company’s building materials can be used to create cabinetry or furniture. The Dakota Burl composite material is created from sunflower seed hulls and provides the appearance of natural burled wood. The material can be stained. 800.324.8187. www.phenixbiocomposites.com.
EastPenn Manufacturing
Deka Solar/PV series batteries offer backup power for renewable energy applications such as solar power, with minimum maintenance required, according to the maker. Batteries are available in flooded, gel valve-regulated, and absorbed valve-regulated varieties for many types of solar applications. 610.682.6361. www.eastpenn-deka.com.
AFM
Using only non-exploited raw materials and 0-VOC colorants, and eliminating formaldehyde and formaldehyde precursors, Safecoat paints are low-VOC and non-toxic. Available in an unlimited range of colors for interior or exterior applications, Safecoat paints come in flat, eggshell, semi-gloss, and satin finishes. AFM produces 40 low-VOC products. 800.239.0321. www.afmsafecoat.com.
AstroPower
The company’s SunChoice line offers two scalable solar electric home power systems designed to operate automatically. SunLine and SunUPS systems feature AstroPower solar panel modules, “plug-and-play” wiring, a power management system, and a mounting kit. SunUPS systems are additionally equipped with batteries to store backup power. 302.366.0400. www.astropower.com.
