Alternative Energy Sources

Now here's a new use for grayfields: The Dutch engineering firm Ooms Avenhorn BV has developed a thermal loop system that siphons solar energy from asphalt and uses it to heat homes and office buildings. The company's patented Road Energy System consists of an underground framework of flexible pipes held in place by a grid and topped off with a heat-absorbing black tarmac. Water passing through the pipes is heated by the asphalt (which is heated by the sun) and then stored in a subterranean aquifer for immediate or future use. In the Dutch village of Avenhorn, heat generated by a 200-yard stretch of road and a small parking lot is helping to power a 70-unit, four-story apartment complex. Click here for more details.

Meanwhile, the Swedish state-held property administration company Jernhuset is looking to harness human body heat to warm buildings, as reported by Agence France Presse. If all goes according to plan, thermal energy generated by the 250,000 commuters who pass daily through the Stockholm Central Station (the nation's largest train station) will be used to heat water in mechanicals behind the station's walls. That heated water will then be pumped to a nearby commercial complex (to be completed by 2010), supplementing HVAC systems for a small hotel, retail shops, and offices. The thermal loop system is expected to reduce the commercial building's heating costs by 20 percent.

The Sustainable Dorm

MTV was the first to document the dynamics of college students living in close quarters, but Duke University has no doubt improved upon the concept. In January, 10 Blue Devil students took up residence in the university's newly constructed Smart Home, a 6,000-square-foot house designed by students from the Pratt School of Engineering and Trinity College, and outfitted with a slew of high-tech, environmentally friendly features.

Planned and built in partnership with the Home Depot-with $2 million worth of cash sponsorship and in-kind donations-the structure stands not only as a handsome addition to campus housing, but as a showcase for green living. Its eco features include a green roof, two solar power systems (one generating electricity; the other, hot water), two rainwater collection systems (providing property irrigation and graywater for toilets and washing machines), and a paperless, mold-resistant drywall system. The home is constructed of sustainable lumber, including Southern Yellow Pine trim harvested from the university's own forest.

Organizers describe the Smart Home as a living laboratory whose inhabitants will explore new building methods, products, and technologies not yet commercially available. Its green features will be constantly evolving. For more details, visit the Duke Smart Home Program.

What's Behind the Label?

The USDA maintains strict labeling standards for food manufacturers wishing to tout their products as "natural" or "organic." But the parameters for building products, processes, and businesses claiming green status aren't so clear. Dozens of third-party green building certification programs have hatched into existence in recent years, each with its own scope and criteria, and some are more rigorous than others. For the mystified, Environmental Building News offers a nifty primer on green certification programs in its January 2008 issue. The overview breaks down various designations for forestry products, indoor air quality, and energy performance, as well as programs that are multifaceted. Click here for the full article.

Speaking of green certification programs, the NAHB is poised to launch its Certified Green Professional designation on Feb. 14 at the International Builders' Show in Orlando, Fla. Intended as a green seal of approval for builders and remodelers, this new form of accreditation will be available to those with at least two years of building experience (including the construction of at least one home in the 24 months prior to the application) following completion of a two-day green course. Candidates must also complete a University of Housing management course, agree to continuing education requirements, and adhere to a code of ethics.

More than 700 builders have completed their preliminary coursework through a pilot launched two years ago. The first class of Certified Green Professionals will receive their designations in May at the NAHB National Green Building Conference in New Orleans. For program details, visit