Published on August 5th, 2013 | by James Ayre


Energy-Efficient Windows Inspired By Nature — New Bio-Inspired Approach To Thermal Cooling Could Be Applied To Solar Panels

August 5th, 2013 by  

A new type of energy-efficient window — inspired by and recreating the vascular networks found within living organisms — has been created by researchers at the University of Toronto. The new windows work effectively to limit heat loss during the winter and provide a cooling effect during the summer. The new design has resulted in 7–9 degrees of cooling in laboratory experiments. The researchers also think that their new technique/design could be applied to solar panels, working to increase their functional efficiency thanks to the cooling effect.

The new process is, in the words of the researchers themselves, a “bio-inspired approach to thermal control for cooling (or heating) building window surfaces,” one that works through the action of optically clear, flexible, elastomer sheets, which are attached and bonded to normal glass window panes. The attached elastomer sheets — which are composed of polydimethylsiloxane (PDMS) — feature ‘channels’ through which room-temperature water is free to flow. It’s this flowing water that provides the thermal controlling effects.

“Our results show that an artificial vascular network within a transparent layer, composed of channels on the micrometer to millimeter scale, and extending over the surface of a window, offers an additional and novel cooling mechanism for building windows and a new thermal control tool for building design,” stated Ben Hatton, lead researcher and a professor of engineering at the University of Toronto.

energy efficient windows thermal cooling solar energy

“A. Schematic of the composite window structure. B. The artificial vascular network layer.”
Image Credit: University of Toronto Faculty of Applied Science & Engineering

As the researchers note, windows currently account for around 40% of all building energy costs — any improvements with regard to their thermal regulatory abilities would be valuable. Hatton continued: “In contrast to man-made thermal control systems, living organisms have evolved an entirely different and highly efficient mechanism to control temperature that is based on the design of internal vascular networks. For example, blood vessels dilate to increase blood flow close to the skin surface to increase convective heat transfer, whereas they constrict and limit flow when our skin is exposed to cold.”

As Hatton notes — the new technique could probably very effectively be applied to solar panels, and could also function well as a means of supplying heated water to existing hot water or heat storage systems.

The new research was just published in the journal Solar Energy Materials & Solar Cells.

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About the Author

's background is predominantly in geopolitics and history, but he has an obsessive interest in pretty much everything. After an early life spent in the Imperial Free City of Dortmund, James followed the river Ruhr to Cofbuokheim, where he attended the University of Astnide. And where he also briefly considered entering the coal mining business. He currently writes for a living, on a broad variety of subjects, ranging from science, to politics, to military history, to renewable energy. You can follow his work on Google+.

  • Alessandra Ribeiro

    Innovations in all
    areas of sustainable energy supply and energy consumption are among the most
    effective tools we have to fight the negative consequences of climate change.
    Existing technologies allow us to substantially reduce greenhouse gases in
    the U.S. by increasing energy efficiency and saving energy, leading to a
    sustainable use of resources. Intelligent climate solutions with clean energy
    provide ecological benefits as well as economic advantages.

  • Biomimicry applied to windows

  • sambar

    propylene glycol or glycerol, 2 non-toxic antifreeze products. We need more info to see if the fluid has to be moved elsewhere or can be cycled within the window structure. This layer would likely be added to the interior glass pane so freezing wouldn’t be a problem, and circulation could be by convection or capillary action.

    I’m sure the minds that came up with this have considered the obstacles.

    • Matt

      Maybe, maybe not. Notice As Hatton notes — the new technique could probably very effectively be applied to solar panels, and could also function well as a means of supplying heated water to existing hot water or heat storage systems.
      But “existing hot water” implies that the heat was moved somewhere. Notice the little tube on the top and bottom. And solar panel are 99.999% outside.

      Note that there isn’t a use for this, but if to work the liquid is moved elsewhere then there is a need for plumbing, which adds complexity and make retro fitting harder.

  • Matt

    Can you say freeze / leak? Sound like the fluid is moved else where to cool off, share its heat. That means plumbing. For PV or window got to worry about it being cold enough to freeze water. If you use anti-freeze now that plumbing has toxic water in it. Sounds like limited applications.

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