Library of the University of Technology in Delft
The university campus is dominated by a concrete structure dating from the 1960s by van den Broek & Bakema. In order not to enter into visual competition with this, the new library was conceived as a continuation of the topography and pushes itself in wedge-like form beneath the surface of the ground. A 40-metre-high truncated concrete cone forms a striking contrast to the gently moulded landscape. The cone is supported on six V-shape pairs of raking columns and houses a four-storey reading space, which is naturally lighted from above via a central void. On its eastern edge, the curved roof is supported by slender, raking steel struts; to the west, it flows into the natural topography of the site. The relatively large area of the reinforced concrete roof with its great storage mass ensures a pleasant indoor climate. In summer, the library is naturally cooled by the evaporation of rainwater in the vegetation layer. To avoid service structures on the roof and for ecological reasons, too, groundwater in an aquifer reservoir at a depth of 45–70 m below ground level is used to warm the building in winter and cool it in summer. As a result of the natural insulation of the reservoir, the water retains virtually the same temperature over the period of the annual cycle. The double-façade construction, with different angles of slope, also supports the natural conditioning of the indoor climate. Air enters the intermediate space at the base and is removed at ceiling level.