Zollverein School has "Active Thermal Insulation"
One would think twice about setting a building next to an abandoned mine shaft, but the Zollverein School of Management and Design takes advantage of it. There is a lot of hot water in the mine that used to be dumped into the River Emscher in the Ruhr Valley. Now the 30 degree C (90F) water is pumped up a thousand metres, put through a heat exchanger, and then circulated through pipes cast the concrete walls, which have no insulation inside or out. Why bother when the heat is free? Designed by SANAA architects Kazuyo Sejima and Ryue Nishizawa, winners of a 2002 international competition. ::Azure Magazine Christine gives tips for visiting the area here