A team of researchers at Pennsylvania State University has investigated the effectiveness of a coating for single-glazed windows that could lead to energy savings in the winter months. Tests showed that the coating can achieve the level of double-glazed windows fitted with an insulating air layer.
The window coating (close-up of the molecules) improves heat transfer from outdoor sunlight (orange arrows) to the interior of the building while ensuring sufficient light transmission (yellow arrow) Graphic: Penn StateHowever, coating single-pane windows with translucent metal films, which can absorb some of the sun's heat in winter without compromising the clarity of the glass, is significantly less expensive than switching to double-pane windows. The energy-saving properties of a coating with nanoscale components that can reduce heat loss and absorb heat better were investigated. The research team carried out the first comprehensive energy-saving analysis of the material in the building sector. Compared to the low-emissivity coating of a standard single-pane window, the photothermal coating absorbed most of the light in the near-infrared region of the spectrum, while the conventionally coated window reflected it outwards. This near-infrared absorption led to a reduction in heat loss of around 12 - 20 % compared to the other coatings and an overall energy saving potential of up to around 20 % compared to a building without coatings on single-pane windows. In Germany, the Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology (FEP) is also conducting research into window coatings that are designed to save heating energy in summer and cooling energy in winter - more on this in an upcoming issue.
The researchers published their findings in the journal "Energy Conversion and Management".
