{"id":19667,"date":"2016-11-02T10:00:27","date_gmt":"2016-11-02T14:00:27","guid":{"rendered":"http:\/\/www.constructionspecifier.com\/?p=19667"},"modified":"2016-12-13T14:21:47","modified_gmt":"2016-12-13T19:21:47","slug":"daylighting-with-dynamic-glass","status":"publish","type":"post","link":"https:\/\/www.constructionspecifier.com\/daylighting-with-dynamic-glass\/","title":{"rendered":"Daylighting with dynamic glass"},"content":{"rendered":"
\"frost-school-of-music\"
Photo \u00a9 Moris Moreno<\/span><\/figcaption><\/figure>\n

by Helen Sanders, PhD
\n<\/strong>As long as humans have built shelters, windows have been an important design element to bring in daylight. In the second half of the 20th<\/sup> century\u2014facilitated by advances in structural engineering and the advent of electric lighting\u2014buildings became larger, deeper, and increasingly isolated occupants from the outside world, especially with the arrival of high-walled workstations. As we have now come to realize, having a connection with the outside world and access to daylight is very important for human health and well-being.<\/p>\n

The World Health Organization (WHO) predicts that by 2020 cardiovascular disease and mental health disorders will be the top two causes of death worldwide; both are impacted by lifestyle and environmental factors. Since we now spend 90 percent of our time indoors, the built environment is a highly influential factor on human health. As a result, in a century where the impact of global warming will also become acute, the design community is wrestling with the dual, and often conflicting, sustainability challenge of creating energy-efficient buildings to minimize environmental impact, and creating human-centric buildings sustaining the health and wellbeing of occupants.<\/p>\n

Daylighting a building not only provides occupants access to needed daylight and a connection with the outside world, but it also offsets the need for electric light and can save significant amounts of energy if automatically dimmable lighting controls are used. The problem with daylight admission involves the accompanying heat and glare\u2014both of which have to be controlled to deliver energy performance and human comfort. To deliver effective daylighting, the envelope\u2019s thermal and solar control performance becomes increasingly critical. Today\u2019s solutions are often insufficient to control the sun\u2019s heat or glare without compromising the daylight design by some means\u2014whether it be by blocking the view, inadequate admission of daylight, or insufficient control of solar gains.<\/p>\n

Electrochromic glass
\n<\/strong>According to the U.S. Department of Energy (DOE), fenestration with dynamic solar control is a key component of a net-zero energy fa\u00e7ade solution. (For more information, see D. Arasteh et al\u2019s report, \u201cZero Energy Windows, Proceedings of the 2006 ACEEE Summer Study on Energy Efficiency in Buildings,\u201d available online at aceee.org\/files\/proceedings\/2006\/data\/papers\/SS06_Panel3_Paper01.pdf<\/a>.) Electrochromic (EC) glazing provides dynamic solar control since it has the ability to change its visible light transmission (VLT) and solar heat gain coefficient (SHGC) at the touch of a button, or automatically based on the input of sensors (e.g.<\/em> for light or occupancy). The ability to tune the SHGC allows:<\/p>\n