Kuggen, an office building in Gothenburg, Sweden is coated in bold shades of red and unlike any sustainable building you've ever seen before. Inspired by both cog wheels (kuggen means cog) and the saw-toothed edge of a leaf, the circular building was designed by Winngårdh Arkitektkontor and is composed of six floors each skewed to the south to provide shade for the floor below. A high performance facade and efficient window placement are combined with solar power on the roof as well as a moving photovoltaic shade screen on the top floor. Aiming for energy efficiency and a cool place to hang out, the office building serves the Chalmers University community and includes public meeting space and a coffee shop too.
Kuggen is located in Lindholmsplatsen and is surrounded by traditional gray buildings on a lively public plaza. The formerly windy site is made more friendly as a result of the circular building, which helps calm the breezes as they wrap around the facade. Inside, the bottom floor serves as a coffee shop and meeting space for employees, faculty and students of the University, with the second floor serving as public space and the top 4 floors holding offices. Each floor is 1.5 meters larger in circumference growing by two windows per floor and is shifted towards the south to provide shade for the floor below.
The dramatic facade is shaped like a cog wheel or the saw-tooth profile of a leaf. The triangular shaped windows let in light where it is needed most, which is at the ceiling, so that daylight can penetrate into the center of the building. Long-lasting ceramic panels serve as the facade’s cladding, which were then painted in bold shades of red. The building’s structure is composed of prefabricated concrete panels that provide thermal mass. Motion-activated natural ventilation and lighting systems help reduce energy use to where and when it is needed.
On the roof, a solar thermal system generates hot water for use inside the building. And the most impressive feature of the building is the rotating sun screen for the top floor. Since the top floor has no shade, a metal track and sun screen was installed on the facade, which tracks the sun, providing shade for the spaces behind. Photovoltaics are integrated into the screen to produce electricity for the building’s use. With all the energy efficiency measures, daylighting and the facade, the building uses less then 60 kWh/sq meter.