Energy: Scaling It Up

You hear a lot about zero-energy architecture these days, but at the time of this writing there are only eight commercial buildings in the United States that can truly claim this distinction—that is, buildings that have been proven to the U.S. Department of Energy’s satisfaction to produce as much energy as they use over the course of a year. And none of them are very large; the biggest is 13,600 square feet. But that is set to change dramatically. Last June, the National Renewable Energy Laboratory (NREL), in Golden, Colorado, opened a new, ultra-efficient research-support facility that at 220,000 square feet is poised to take zero-energy buildings to a far vaster scale.

The secret to the building’s efficiency is a mix of high-end technology—like
a 55,000-square-foot array of rooftop photovoltaics—and surprisingly low-tech solutions. One key to the design is an underground “thermal labyrinth,” essentially a crawl space with a maze of concrete walls that stores and slowly releases warm or cool air, depending on the season. The idea for the labyrinth came from the area’s poor soil quality, according to Craig Randock, a principal of the Denver-based firm RNL, which worked with Stantec and Haselden Construction to realize the $64 million project. “You’ve got to dig way down to the rock,” Randock says. “And we thought, Well, we can actually use it as a big thermal battery.”

We asked RNL to create a diagram of the NREL facility’s major sustainable features, which have put it on track to receive LEED Platinum certification and, if it continues to perform at current levels, to become the country’s largest zero-energy building.