Our future selves might look back and wonder how we ever handled having just plain old glass in our windows. Curtains or blinds might get the flick in favor of a variety of smart windows that can tint themselves or turn opaque on command, and now a team of German engineers has demonstrated a new design. Dubbed Large-Area Fluidic Windows (LaWin), the system uses iron particles suspended in liquid to block sunlight at different levels and harvest heat energy from the Sun.
Most of the smart window systems we’ve seen in the past are electrochromic, meaning they change tint or opacity in response to electrical signals passing through wires embedded in the glass. That lets users cloud the window over if they want both privacy and natural light, or darken the glass to keep the house cool.
This new system has similar applications but takes a completely different approach. To make a fluidic window, magnetic iron nanoparticles are suspended in a liquid, which is contained inside vertical channels in the glass itself. These particles cloud up the window, blocking light to different degrees and soaking up heat as needed. When you want to make it transparent, switching the LaWin on triggers magnets to pull these particles out of the liquid.