Nature-inspired 'skin' paves the way for smarter, more efficient buildings

Is it possible to build a smarter building without installing loads of expensive sensors? According to two Berkeley professors, yes.
Written by Andrew Nusca, Contributor

Is it possible to build a smarter building without installing loads of expensive sensors?

According to two University of California Berkeley professors,yes. In a new project recently proposed to the National Science Foundation, bioengineer Luke Lee and architect Maria-Paz Guttierezsuggest that a building's skin needs to become as smart as nature -- that is, adaptable.

The solution? Enough sensors, actuators and information to provide real-time feedback loops, layered on top of a flexible building design that shuns braces, gussets and other rigid engineering inventions.

Architecture, meet bioengineering.

The project is called Biologically Inspired Self-Activated Building Envelope Regulation, or SABER for short. In it, Lee and Guttierez suggest the development of a thin-film membrane to act as a building's "skin," allowing control of humidity, light and temperature.

That's important, because heating, ventilating and air-conditioning (HVAC) systems account for 39 percent of the energy used in commercial buildings in the United States, according to the National Institute of Building Sciences.

What's more, buildings account for 36 percent of total energy use, 65 percent of electricity consumption and 30 percent of greenhouse gas emissions in the United States, according to the U.S. Green Building Council.

Writing for GreenerBuildings, Berkeley professor Tom McKeag explains that the SABER project uses the environment as an actuator. For example, excess moisture triggers the membrane to open and equalize, reducing humidity to an acceptable comfort level.

It's not the first time researchers have thought to automate a building, but the scientists say it's the first bio-inspired way about it -- no mechanical elements necessary.

The film in question is made of several passive layers that work by material properties. Two alternating rows of cells that provide openings actuated by either external light or internal humidity. The film is also protected by an external moisture barrier to keep water out -- with a high contact angle, it functions much like the wax on some types of leaves -- and an internal layer of silica gel to reduce moisture inside.

In the first type of cell, micro-lenses embedded in the film direct light to tiny pockets of photoactive hydrogels that contract in light and open elastomeric microventuri tubes that allow for greater airflow.

In the second type of cell, a hygroreactive polymer expands with increased moisture to open microvalves to allow for more airflow.

McKeag explains why this nature-inspired approach is "fundamentally different" than previous approaches:

Many have long argued that we design and make buildings in a flawed way. It is only relatively recently, however, that alternatives have been proposed that employ paradigms, rather than just forms, from nature. Are these paradigms just extensions of the old “building as machine” utopian dream? I think they are fundamentally different and will outline below why I think so and describe one of the pioneering partnerships that may change the way we make buildings.

In his essay, McKeag suggests the following:

  • Current building techniques "top down blueprints" and nature's method "bottom up recipes" are at complete odds with each other.
  • Modular construction is nature's foundational element.
  • "We combine building materials; nature integrates them...solutions in nature flow through the hierarchy of scales to facilitate function."
  • We build for stability and stiffness; nature builds for toughness and durability.
  • For nature, "'unchanged' means 'dead.' "

Perhaps the most important point: with a smart, nature-inspired building, you've not only saved all that energy used to control a building's environment, but you've also built a more durable system in the first place.

More information: USGBC - A National Green Building Research Agenda (2008; .pdf)

Illustration: Blake Kurasek/Jacob K. Javits Convention Center, New York, NY

This post was originally published on Smartplanet.com

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