The best of both worlds
Former biology student Doris Sung experiments as an architect with thermobimetal and draws inspiration from the protection mechanisms of the human skin. In this interview, she talks about the fascinating potential that this yields for facades and climate management.
Doris Sung has had a university career marked by diversity. Having initially devoted herself to the natural sciences and studied biology, she discovered architecture for herself. Today she unites the two disciplines. As an architect, she has studied the human skin and compared it with the facades of buildings. Her goal is to apply the extremely effective mechanisms of protection and adaptation of our skin to the skins of buildings. For, like our skin, an intelligently designed facade can provide protection from overheating and regulate energy consumption. The solution is smart materials.
In Los Angeles, Sung and her team at dO|Su Studio Architecture develop thermobimetal and other shape-memory alloys. Even after major deformation, e.g. due to heating, these memory metals return to their original shape. Thermobimetal consists of two metals connected together that act differently on exposure to heat because of their different coefficients of thermal expansion. If, for example, a thermobimetal is heated to a certain temperature on exposure to the sun, it rolls up. Making use of this predictable behavior, the architect has designed self-ventilating buildings and facades with integrated solar protection that operate without external energy or control.
CORPUS: Mrs. Sung, you are a former biology student turned architect. Could you please tell us about the process behind this seemingly huge change of fields? How does your knowledge of biology affect your present work?
DORIS SUNG: There was no rhyme or reason to the switch at that time. My plan was to go to medical school after graduating from college. Unknowingly, the liberal arts education at Princeton opened up a lot of new worlds for me. At graduate school I started to ask crazy questions like: why can’t building skins be an extension of the human body? Why can’t they be kinetic, or even alive? It is not until more recently, looking back on my body of work, do I realize that so much of it has been influenced by my early years in biology. From behavior systems to body mechanisms to cellular distribution and growth patterns to ge-ometry in microorganisms, I subconsciously and constantly look to biology for inspiration.
CORPUS: As an architect you seem to experiment a lot with different materials. How would you describe your approach to architecture?
DORIS SUNG: I am extremely lucky to work in an area of architectural research where I get to ask my own questions and spend much of my time trying to answer them. Having the freedom of not working for a client is liberating. I used to do that for many years – and enjoyed it for different reasons. In many ways, the process of design was very top-down, meaning you start with a bigger idea and spend design development detailing that idea. Now, things are the opposite. Almost all of my projects are bottom-up, where we start with a specific movement behavior of the material, develop a single working unit and then speculate on what it can be when multiplied across a surface or structure. Most times, we have no idea what the final application will be until late in the process. This process is very exciting because the outcome, although seemingly logical in retrospect, is a surprise even to us. It forces us to understand the significance on one small thing in its contribution to the big picture.
CORPUS: When developing your thermal bimetals you compared human skin to building skin. What is special about these materials? Are your findings still relevant for your daily work?
DORIS SUNG: Anything we can make cannot compare to the complexity of human skin. We cannot even come close. But, if we start to think in terms of making building skins breathable instead of hermetically sealing the interior environment of the building from the outside, then we start to consider a whole new way of designing buildings. This attitude begins to influence so many other aspects of architecture such as self-structuring systems, self-assembly systems, automatic propulsion and easy construction methods. Automobile and transportation technology is so far ahead of architecture. Somehow, the building industry has to sprint to catch up to other technologies around us.
CORPUS: Do you use other bionic methods elsewhere?
DORIS SUNG: I have been using thermobimetal, not necessarily because I think it is the most amazing material, but because I don’t feel that I have exhausted all the possible applications. Each time I finish one project, it opens doors to yet another one. I also have been working with other shape-changing polymers like polystyrene. There is so much to work on, but not enough time!
CORPUS: Working with “unstable” materials must be quite different from working with static ones. Are there specific calculations or other aspects that have to be taken into consideration?
DORIS SUNG: Working with unstable materials is very different. With static materials, it is common to draw and delineate in two-dimensions while imagining and designing in three-dimensions. With smart materials, you have to consider the fourth dimension, which has an infinite amount of three-dimensional forms it takes, but rarely the same, day-to-day. Although we use software to simulate the process, it doesn’t take in account problems with simple behavioral elements from gravity, friction or wind-resistance. This is the most challenging part of what we do and something that is not traditionally taught in architecture school or in the sciences.
CORPUS: How could thermal bimetals affect the sustainability of a building? Are changeable materials adaptable to our concept of building and living?
DORIS SUNG: Because thermobimetal reacts to outside temperature or the moving sun, we can program the geometries to respond at certain times of day so that the operation would be optimized when needed. For example, during the sunniest times of day, mechanisms made of thermobimetal can be designed to shade and block out the sun to prevent heat gain. When it is cool outside or overcast, the system will not activate and can even allow the sun to penetrate the building and add welcome heat during the wintertime. It is also important to point out that the material requires no energy and no controls. They respond automatically and cannot be tampered with. A power outage does not affect the operation. We are currently working on a self-shading window unit. It’s very cool and incomparable to any product on the market.
CORPUS: Ms. Sung – many thanks for the exciting interview.
Biography in brief
After receiving her B. A. at Princeton University and M. Arch. at Columbia University, Doris Sung worked in various offices in cities across the U.S. before arriving in Los Angeles in 2001. She developed her research focus while teaching at University of Southern California (USC) and the Southern California Institute of Architecture (SCI-Arc). In 1999, she opened her office, dO|Su Studio Architecture, and soon received many American Institute of Architecture (AIA) and American Society of Interior Designers (ASID) awards for her work, including the prestigious accolades of AIA Young-Designer-of-the-Year, ACSA Faculty Design Award, R+D Honorable Mention from Architect Magazine and [next idea] award from ARS Electronica. Ms. Sung is currently mainly working on the development of thermobimetal. Her work is funded by a variety of institutions.
If somehow we can program building skins to have intelligence of their own, we can move away from making buildings as hermetically-sealed capsules and consider them to be more like organisms, living amongst a complex ecosystem.
Room for ideas - Metal that breathes
Flexible shape changers
Thermobimetals offer a wide range of applications. Although initial research into these shape-changing alloys was carried out many years ago, their range of applications is still being constantly extended today.
Two different sheets of metal – one smart outcome
Thermobimetals or bimetals are layered composites consisting of at least two metals with different coefficients of thermal expansion. On heating, one metal expands more than the other(s) and thus causes temperature-induced bending. The degree of bending depends on the difference in thermal expansion.
A multitude of different material combinations is possible to suit the application and the required change in shape – such as iron and copper or aluminum and iron.
In the production of thermobimetals, suitable sheets of metal are rolled or plated onto one another and thus firmly joined together.
When heated, e.g. in direct sunlight, the thermobimetal changes its shape – it rolls up. The intensity and timing of movement depend on the chosen material combination.
Thermobimetal structures can open at a predetermined minimum temperature in order to generate air flows – and thus provide an autonomous ventilation system.
Moved by heat
Thermobimetals are used in numerous technical applications, e.g. in the production of bimetal switches and in a variety of ways in the construction sector. The architect Doris Sung and her team have started to use thermobimetals as a main element of building structures. For their projects they calibrate and design various thermobimetallic elements so that they change their shape predictably when heated, e.g. on exposure to sunlight. The interconnected thermobimetals are never entirely identical, and each structure is created on the basis of special calculations. This way, initially light-permeable materials change autonomously into a shade-imparting wall; or an initially closed surface opens up in certain areas and thus becomes a self-controlling climate regulator.