As architects and engineers search for ways to make buildings more energy efficient and comfortable for inhabitants, focus turns increasingly towards dynamic building envelopes. Exploiting advances in technology, architects and engineers are becoming more and more ambitious about what the building envelope can accomplish. Not surprisingly, the most ambitious are striving not only to conserve energy but to harvest it.
At Urban Green Council’s recent Author Talk, Russell Fortmeyer spoke about “kinetic” facades—building envelopes that respond to outside conditions and the needs of the people inside. Citing examples of buildings with mechanical louvers, Fortmeyer pointed out that the basic principles of sustainable architecture have been around for hundreds of years. We are “in a sense just rediscovering them and figuring out how to re-integrate them into architecture and engineering.”
Speaking about early automated facades, Fortmeyer referenced two projects from the 1980s. The Occidental Chemical Center in Niagara Falls had automated louvers that would rotate to redirect sunlight during the day and close at night hold heat inside. Unfortunately the building was not appropriately maintained and fell into disrepair rather quickly. The Arab Institute in Paris had a southern façade made up of hundreds of light-sensitive diaphragms that automatically regulated the amount of light entering the building. Unfortunately there is some debate about whether this building “works (now), never worked, or always worked.” Which raises important questions, including: What does it take to maintain these highly responsive buildings? Will automated systems always fall into disrepair more quickly than mechanical systems? Or, should we be optimistic that automation technology is becoming more robust?
Over the past 25 years, advances in sensor technology have allowed architects and engineers around the world to design buildings with a wide variety of building envelope innovations. Serious challenges still exist: How do you position louvers to block sun without blocking views? How do you effectively integrate a responsive facade with a building’s lighting, cooling, and ventilation systems to maximize energy efficiency (reduce solar gain and demand for artificial lighting, cooling, heat) and improve thermal comfort? And, once you construct the building, as Fortmeyer points out, who is responsible for the “operability of each feature of the façade? Who puts the controller in. the electrical engineer or the control contractor? Who wires the controller to the building automation system? What specification does that lie in?”
Four recent projects of particular interest include:
Sony City Osaki in Tokyo, Japan (by Nikken Sekkei, completed in 2011) – featuring a bioskin façade that cools the exterior of the building by running collected rainwater through ceramic pipes.
Al Bahr Towers in Abu Dhabi (by Aedas, completed in 2012) – featuring a lattice of fiberglass triangles that move with the sun, to reduce solar gain and glare, and close completely at night.
Design Hub, Royal Melbourne Institute of Technology in Melbourne, Australia (by Sean Godsell, completed in 2012) - featuring a double-skin facade with passive cooling system and outer layer of 16,000 glass discs, which pivot to block the sun. The discs can be replaced with solar cells when the technology is adequately advanced.
Perhaps the most whimsical project is the recently completed BIQ House in Hamburg, Germany (designed by Splitterwerk Architects, ARUP, Colt International and Strategic Science Consult, completed in 2013), an experimental net-zero apartment that features a bio-reactive façade. The building grows microalgae within the façade that both shades the building and can be harvested to provide energy for the building.
Keep your eyes open for more of this next generation of building envelopes that will generate energy as well as conserve it, including high-efficiency solar power systems like the one being developed at the Center for Architecture, Science and Ecology at Rennselear Polytechnic in Brooklyn, New York, which they call an “Integrated Concentrating Solar Façade” (ICSF).