There's an old joke that the Army Corps of Engineers' solution to any problem is simply to pour more concrete. Well, you wouldn't know it to view the agency's Northwest District headquarters, which not only places in the top 1 percent of energy-efficient office buildings nationwide, but is also light, airy and abundant with wood, glass and flowing spaces -- all on a reclaimed and remediated Superfund site [sources: Gendall; Goodman].
Designed by ZGF Architects and built by Sellen Construction, the building channels light from a central atrium and exterior windows into various meeting spaces, while low-slung cubical walls allow light to penetrate the cubicle bullpen as well. Window shading outside and inside controls heat load, as does the use of clerestory windows. Wooden sections were built in part using materials reclaimed from a nearby decommissioned warehouse. To keep the inside cool, exterior air passes through MERV 15-level filtration to flow through the floors, chilled sails cool the indoors via radiant cooling principles and a thermal storage tank employs a phase-change material (PCM) to pack away cooling energy against future need [sources: Gendall; Goodman].
By the way, minimum efficiency reporting value, or MERV, is an air filter effectiveness rating, and it's based on worst-case-scenario performance. So a MERV 15 filter like the one described here is 85-95 percent efficient at removing particles measuring 0.3-10 microns -- the scale of sneeze particles and individual bacteria [sources: EPA; Wilkinson].