A thin, transparent, convective cooling layer applied to building windows and solar panels can reduce building temperature by up to 6 degrees and increase thermal regulation, say researchers in a paper published by Solar Energy Materials & Solar Cells.
Borrowing ideas from nature to boost energy efficiency, researchers from Harvard University and the University of Toronto have developed polydimenthylsiloxane (PDMS) sheets that contain microscopic patterns similar to veins on a leaf, that allow the passage of temperature.
Author Ben Hatton, an engineering professor from the University of Toronto, collaborated with colleagues at Harvard to develop the flexible sheets that can be applied to glass in existing windows. He points out how windows are a huge source of inefficiency in buildings and so they represent a huge opportunity for improvement. Also, 40 percent of a building’s energy costs can be linked to windows and the researchers found that emulating nature can boost efficiency significantly.
Hatton told Sourceable that unlike man-made thermal control systems, living organisms have developed a very efficient way to control temperature based on the design of their internal vascular system. Lab experiments have demonstrated that the liquid microscopic channels in the PDMS sheets can reduce a building’s temperature by up to 6 degrees in small and big buildings, he says.
The authors say that the same technology can also be applied on solar panels, to boost their efficiency.
The Department of Energy says that in the winter months, windows can account for 10 to 25 percent of a home’s utility bill through heat loss. It also says that in a typical residential or commercial building, about 42 percent of energy is lost through doors, roofs, attics, walls, floors and foundations – known collectively as the building envelope. To address this, it announced in December 2012 that it will invest $9 million in to tighten building envelopes.