Windows have been part of our buildings for hundreds of years. Glass allows in sunlight and keeps most of the weather out. But windows have a serious drawback when it comes to sustainability – they conduct out heat in the winter and in during the summer– accounting for 25% of building heat losses. Scientists have been working on this problem, and have developed aerogels that can be sandwiched between glass to reduce the problem. Aerogels are materials made up of mostly air with very low thermal conductivity.
Much like your car windshield, these windows are made of layers of glass with other transparent materials that enhance properties like strength and heat transfer. In 2018, a group of scientists created an aerogel from beer wort that was transparent and an excellent insulator. A group from UC Boulder furthered that research with aerogels that can be made with cellulose from food waste and bacteria suitable for windows for future missions to Mars or the Moon. A third group with the US Department of Agriculture created an aerogel with wood pulp that has optical transmittance comparable to glass (~91%) and a thermal conductivity five times less than that of glass. The process is similar to growing crystals used in HDTV’s and smartphone screens.
So, who knows? Your next window may have the flavor of your favorite beer or snack, but it will help keep you warmer in the winter and cooler in the summer. – Steve Terry, DTC HVAC & Refrigeration Instructor
