By Jody McCutcheon
Sun-worshipers, take note. The Heliotrope houses of Germany literally follow the sun on its daily rotation. Brainchild of architect Rolf Disch, the building prototype is the first of its kind, producing more energy than it consumes—emission-free, 100% renewable and carbon-dioxide neutral. Disch even coined a name, PlusEnergy, to describe buildings with a positive energy balance.
The architect’s personal home in Freiburg was the world’s first PlusEnergy home, followed by a commercial showroom in Offenburg and a dentist office in Bavaria—proving the architecture is suitable for both residential and business. Made mostly of wood, like an industrial-sized treehouse, the Freiburg house rotates 180 degrees throughout the day, tracking the sun to maximize light and natural warmth. What striking, ever-changing views it must offer.
The Heliotrope house consists of two halves. The side with triple-paned windows captures solar heat, while the other side is sheltered and insulated, ensuring a cool environment even at toasty external temperatures.
The Heliotrope’s power sources include a geothermal heat exchanger, a combined heat and power unit, a dual-axis solar photovoltaic tracking panel on the roof providing 6.6kW of power, and solar-thermal balcony railings for heat and warm water. A grey-water system collects rainwater for cleaning dishes and clothes, while wastewater is cleansed in a front-yard, vegetated cascade pond. A dry-compost system eliminates toilet waste. All told, the house produces about five times more energy than it consumes.
The catch, of course, is the price. The estimated two-million–dollar price tag isn’t cheap, but in time (errrmm…a LOT of time!) it likely would pay for itself through heating-cost savings, not to mention the surplus energy that would be fed back into the nation grid.
Plans are in the works for a rotating Heliotrope hotel. Imagine the price for a suite…