The Marxer building on a rare sun-splashed January morning in Vaduz.
An “active energy building” bristling with new technology has officially spread its sophisticated wings in Vaduz, Liechtenstein.
The six-year project was directed by Anton Falkeis and his wife, Cornelia Falkeis-Senn, world-renowned architects based in Vienna. Their client, Liechtenstein attorney and banker Peter Marxer, challenged them to design a sustainable apartment building that relies as much as possible on renewable energy.
A team that included energy experts from the Lucerne University of Applied Sciences and Arts was assembled for the complex task. Countless hours of planning, research, design work, computer modeling and prototyping produced a number of innovations used in the 12-unit Marxer building, including:
• An array of 13 photovoltaic panels that rise from the roof and track the sun’s path across the sky, optimizing the collection of solar energy.
• Load-bearing structures that mimic nature in appearance and function.
• “Acoustically active” three-dimensional interior lighting elements that act as sound diffusors and absorbers.
Anton Falkeis and one of the PCM-filled climate wings.
• Seven “climate wings” that fold out of the building facade and absorb, store and release thermal energy as needed to keep the interior comfortable.
The computer-controlled solar panels, which measure up to 14 square meters, rise from the roof at sunrise and turn with the sun during the day. When night falls or inclement weather approaches, the panels automatically fold back into the roof. The system is said to collect nearly three times the solar energy of stationary panels.
Anton Falkeis described the project as a “prototype for a decentralized urban energy production system that’s part of a bigger network.”
“We created an energy cluster with the surrounding buildings, some of which are owned by the same client,” he said. “We share the energy generated by our PV trackers embedded in the roof structure first with the cluster. We sell any surplus to the grid. The utility can use the surplus to refill the hydro power plant storage.”
The climate wings contain 1.4 metric tons of Rubitherm PCM enclosed in aluminum tubes.
Each climate wing contains rows of PCM-filled aluminum tubes.
Four wings on the building’s western side are dedicated to heating. They are filled with PCM that has a melting point of 31 degrees Celsius. In cold months, these wings open during the day, exposing the PCM to solar radiation that melts the material. Each wing folds back at night and connects to ventilation systems in the adjoining apartments. The tubes release heat as the PCM solidifies, and low-power fans move the warm air throughout the apartments.
Three wings on the eastern side are dedicated to cooling. The PCM in these has a melting point of 21 degrees C. In summer, the wings open at night, allowing cool air to solidify the PCM. Each wing folds back against the building during the day and connects to the adjoining ventilation systems. Indoor air is cooled as it flows past the frozen PCM in the wing.
Ducts carry air warmed by PCM into the apartments.
With a surface area of 24 square meters, the western wings are said to generate about 10 percent of heating capacity. The eastern wings, with a surface of 15 square meters, generate around 16 percent of cooling capacity.
How did the team address flammability issues associated with biobased PCM?
“We developed the encapsulation so that no oxygen can come in contact with the PCM,” Falkeis said. “The whole thing was tested to 300 degrees Celsius, heating up, cooling down, heating up. And finally we got permission by the building commission, a Swiss testing certificate, to use it in the building envelope. Swiss testing accreditation is valid all over Europe.”
Aside from patent applications, what’s next for all this ground-breaking technology?
“We need to reduce complexity and try to produce more standardized building envelope panels or systems that could be part of a regular building system,” Falkeis said. “This is our next step: Reducing the complexity in terms of form.”
He also hopes to spread awareness. "Active energy building" technology was on display at a New York City exhibition that ended in January. The exhibit opens in Los Angeles on March 1; after that, it will be on display in Vienna and Berlin.
Now that the complex project is complete and the first tenants have moved in, the architect says he is "very happy" with the results.
“There’s a lot of architectural and technological detailing,” he said. “There are more than 800 drawings just on detail. It’s very precise. It’s very well done. Very high standards. It’s really crazy how finally everything came out like we planned it. It was six years of hard work, being on site, checking everything. … It was a sort of never-ending ongoing research project. It was really exciting to be part of this.”
The east side of Marxer building faces a small park, a biking trail and a creek.