Green-Roofed Minneapolis Central Library is a Civic Lesson on Eco Design

Minneapolis has the third largest library collection per capita in the US -- and one of the greenest libraries to tuck that collection into. The Minneapolis Central Library by <a href="http://www.pcparch.com/#">Pelli Clark Pelli</a> features a huge atrium that cleaves the building into layers of light-filled spaces to help catalyze visitors to search for the perfect book and sit down with it for a spell. A series of <a href="http://inhabitat.com/mecanoos-tu-delft-library-crowned-with-a-massive-green-roof/">green roofs</a>, advanced cooling and heating systems, and low-energy lights slash the library's energy use by nearly a third, making the building a lesson in how deep green design benefits everyone.

The Central Library links the arts district to the west and a major shopping and business district to the east.

The striking design is centered around the huge<a href="http://inhabitat.com/anz-centre-is-australias-largest-greenest-office-building/"> atrium</a> and the projecting <a href="http://inhabitat.com/photos-denvers-first-leed-gold-school-and-zero-energy-community-campus/">cantilevered awnings</a> on either end. The jutting “wings” are welcoming features that invite the community to come on in and take a look.

nside is a main lobby, where light scoops fill five open floors with<a href="http://inhabitat.com/crystalline-domed-mansueto-library-features-robotic-book-retrieval-system/"> natural illumination</a>.

The interior has no supporting walls so the spaces can be adapted to whatever current and future needs dictate.

The light elements such as the self-supporting stair and glass railings and elevator makes the interior feel very much connected.

Local Minnesota limestone is layered in-between the exterior glass plates as well as the interior floors, giving the library a sense of place. Other materials were chosen for their low-VOC ratings or high levels of recycled content.

The top of the building features three prodigious<a href="http://inhabitat.com/seattles-ballard-library-pairs-a-sweeping-green-roof-with-natural-light/"> green roofs </a>totaling 18,500 square feet that help the library stay cool inside.

The roof serves as a huge sponge during the rainy season, when it infiltrates and cleans storm water.

The roof also provides natural habitat right in the middle of downtown and reduces the dreaded heat island effect, keeping the local environment from overheating on a mid-summer day.

Underfloor displacement cooling technology adds 20% running efficiency, and the entire building is 27% more energy-efficient than code.