Built originally in 1994 as the private residence and special project of Rolf Disch, the Heliotrope is a one-of-a-kind design. The Heliotrope in Freiburg was the first building in the world to create more energy than it uses, of which is entirely renewable, emissions free and CO2 neutral. The structure physically rotates to track the sun, which allows it to harness the maximum natural sunlight and warmth possible. Several different energy generation modules are used in the building including a 603 ft dual-axis solar photovoltaic tracking panel, a geothermal heat exchanger, a combined heat and power unit (CHP) and solar-thermal balcony railings to provide heat and warm water. These innovations in combination with the superior insulation of the residence allow the Heliotrope to produce anywhere between four to six times its energy usage depending on the time of year. The Heliotrope is also fitted with a grey-water cleansing system and built-in natural waste composting. At the same time Freiburg’s Heliotrope was built, Hansgrohe contracted Rolf Disch Solar Architecture to design and build another Heliotrope to be used as a visitor’s center and showroom in Offenburg, Germany. A third Heliotrope was then contracted and built in Hilpoltstein, Bavaria to be used as a technical dental laboratory. Disch’s unique design accommodates different utilization from private residences to laboratories, and nevertheless maintains the structure’s positive energy balance. In addition to the original Heliotrope design, Rolf Disch has drawn plans for larger versions of the project to be built as a rotating hotel, which gives every guest a beautiful view, as well as administrative buildings and even an exhibition pavilion for the EXPO 2010 in Shanghai.