ANSI - American National Standards Institute
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Catching Rays: Spotlighting Solar Technology Standards

New York, Jul 28, 2003

The debate over global warming and environmental policy is rising with the mercury in 2003, which happens to be one of the hottest years on record. Arguments behind reducing greenhouse gasses by embracing renewable energy sources support a new focus on the technologies that can harness them.

According to Shell Solar, the Earth receives as much energy from sunlight in 20 days as is believed to be stored in the Earth’s entire reserves of coal, oil and natural gas. To capitalize on this amazingly abundant resource, applications of solar technology continue to expand their reach. As solar energy systems are increasingly incorporated into designs to power everything from lawn mowers to skyscrapers, standards for these technologies play an important role.

One of the most common solar technologies is photovoltaic: the conversion of sunlight directly into electricity via semiconductors such as crystalline silicon or various thin-film materials. Groups of PV cells are electrically configured into modules, which can be used to charge batteries, operate motors, and to power any number of electrical loads. Underwriters Laboratories standard, UL 1703-2000, Flat-Plate Photovoltaic Modules and Panels, covers flat-plate photovoltaic modules and panels either intended for attached installation on buildings, or freestanding construction. The standard works in accordance with the National Electrical Code, ANSI/NFPA 70-1999, as well as Model Building Codes.

International Electrotechnical Commission (IEC) Technical Committee 82, Solar Photovoltaic Energy Systems, develops International Standards for crystalline silicon and thin film PV devices, concentrator modules, certification of PV products and accreditation of PV test laboratories, and balance-of-system components such as charge controllers and power conditioners. Future projects of TC 82 will address several system and component safety issues including grid-connected systems on buildings and utility-connected inverters. A new working group is planned to deal with various aspects of environmental protection, including safeguarding the natural environment and disposal of toxic PV materials.

Passive solar heating (as well as cooling and daylighting) is another type of solar technology. Many large commercial and government buildings utilize passive solar collectors for heating of air. A solar ventilation system can preheat air as it enters a building by way of a "solar wall": a south-facing solar collector constructed of dark-colored sheet metal and perforated with tiny holes. Outdoor air is drawn through the holes and heated as it absorbs the wall's warmth, then circulated through the building’s ventilation by ducts and fans. A solar ventilation preheating system is the most efficient solar air-heating system available today, but still must conform to safety standards such as ANSI/ASHRAE 62-2001, Ventilation for Acceptable Indoor Air Quality, which specifies minimum ventilation rates and indoor air quality to minimize the potential for adverse health effects.

Passive solar technologies also incorporate design features such as large south-facing windows and building materials that absorb and slowly release the sun's heat. Some structures have achieved the ultimate benefits from passive solar heating and cooling. The Solar Living Center is a 12-acre property in Hopland, CA, that serves as a demonstration site for renewable energy and sustainable living technologies. The Solar Living Center is so adept in its capture of the varying angles of the sun that additional heat and light are nearly unnecessary. In fact, the building is able to sell the excess power it generates to the electric company and buy it back as needed.

Americans could find themselves shopping for homes similar to the Solar Living Center in the near future. The U.S. Department of Energy's Zero Energy Homes research initiative is partnering with various organizations – like ANSI member, the NAHB Research Center – to encourage innovations in homebuilding. A Zero Energy Home (ZEH) employs state-of-the-art, energy-efficient construction and appliances with commercially available renewable energy systems such as solar water heating and solar electricity. This combination can result in net zero energy consumption.

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