Doris Kim Sung looking on over her breathable metal skin.

Isn’t air conditioning in temperate climates an unnecessary waste of energy? Bearing in mind that 30-40% of all the energy we consume around the world goes into fueling buildings, it does make you wonder, wouldn’t it be more efficient to open a window instead? Frustratingly however, it’s simply not possible to open windows in many high-rise office blocks even if you wanted to.

Modeled on humans

That is why biologist turned architect, Doris Kim Sung, is working on another energy efficient and passive method of ventilating buildings, taking inspiration from the human body in search of a more sustainable design. She is advocating the fairly simple yet ingenious idea of a breathable skin, like that of the porous human skin, to encase buildings.

I found a material that was so simple and has been around for about a hundred years

Sung says, “A lot of the things that my colleagues were doing required some kind of energy. They had some very cool ideas but I was looking for a material that would be smart but could just do it automatically. I looked high and low at all kinds of stuff and I found a material that was so simple and has been around for about a hundred years and I couldn’t understand why no one had applied it to this idea yet.”

The material she is talking about is a thermo bimetal strip (two thin pieces of metal such as copper and steel stuck together). These two metals expand and contract differently when heated and cooled which causes the metal to bend one way when hot and the other way when cold.

An ancient idea

According to Sung, this is not a new design but has been in use for various applications for over a hundred years. She says, “The most common application for it is in thermostats. If you open up a residential thermostat, there is a metal coil and that is made out of bimetal. You also see it in thermostats in machinery and automobiles. There are different alloys you can laminate so that they can react at different temperatures. Obviously, in an automobile it will react at a much higher temperature than a residential thermostat.”

There are two main applications that Sung has in mind for the bimetal, both of which are ways of cooling the building without requiring any additional energy other than the sun – this approach in architectural parlance is called passive solar.

“I’m proposing to use it on the skin of buildings for a few different purposes. One is as an automatic sun-shading screen and the second basic application is for ventilation as a way to release hot air from the building.”

The definite hope is to reduce the necessity to require air conditioning

Taking the first application, when direct sunlight hits the bimetal strips they bend inwards and close together, shading the building. This can be especially useful with buildings that are largely made of glass and can turn into boiling sun traps in the summer. Similarly, with the second application, the metal could bend in such a way when the building heats up to open pore like holes in the skin of the building and release some of the heat.

Goodbye to air conditioning?

While it maybe ambitious to be entirely rid of air conditioning in the near future, it could certainly help in reducing energy consumption. Sung says, “I don’t know if we will ever get to the point where we can truly be rid of air conditioning, especially in certain parts of the world, but the definite hope is to reduce the necessity to require air conditioning. It is trying to move to a more holistic way of building architecture. If we could reduce the amount of air conditioning or heating used just by making buildings more passively designed then we have saved a lot for buildings.”

Check out Doris Kim Sung’s TED talk to see the bimetal in action:

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The End
  • JackT

    Interesting idea, but impractical. Further, I must disagree with the closing claim these tiles will work efficiently and endlessly. As a mechanical engineer I look at all this complexity (thousands of unique tiles? Really?) as near countless opportunities for failure.

    • Anonymous

      Good point Jack. As an engineer in what ways do you reckon the indivdual parts could fail?

      • Will Dissolver

        Metal fatigue, for one…

    • John Anderson

      Seems like thousands of bendy pieces of metal (especially if placed so they can’t collide) are less complex or fault-prone that the mechanical systems needed to power a fleet of air handlers.

      • Anonymous

        I agree. Thousands of individual units (even if say, 50% fails), means that you’re getting at least half efficiency.

        If you rely on a single air conditioning unit as most structures are now) and that one unit fails, you are getting 0% efficiency until fixed.

        Additionally, replacing a window is much easier than a compressor + control electronics.

        What you DO lose is a degree of control. There’s no “cooler” or “warmer” switch.

        Granted “endlessly” is a bit of an exaggeration, as things eventually will rust or fail.

  • Alex Dureich

    uh…you know, if you live in a humid climate, opening the window just lets all the humidity into your home? then you have to worry about mold and mildew…damp paper that curls as it dries…etc etc…

  • Dan M.

    I guess I’m firstly concerned with that this would basically bring the outdoors inside. How are you going to filter the air of allergens, dirt, ‘smell’, next door’s cooking against yours, and let’s not forget the biggest of all: rodents and pests. Guess I’ll have a permanent dust buster connected to my electronics for the quintuple in build up.

  • Anonymous

    I wonder how well these panels hold up to the weather. Even the most hardened surfaces need maintenance every 4-5 years due to weathering effects, these don’t seem that robust in comparison. Interesting idea though, might work well in areas that don’t experience extremely uncomfortable weather on either extreme.

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