VG SmartGlass is developing a film-based light and heat control window insert called INVISIBLIND that could reduce the energy required to light and cool perimeter spaces by 30% compared with spaces without heat and glare control. A potential advantage of INVISIBLIND is a 75% cost reduction relative to other solutions on the market along with ease of retrofit into existing buildings. In addition, the technology offers other value propositions in the privacy and window branding markets.


Heating, cooling, and lighting represent the three largest energy uses in commercial buildings. Next-generation windows and building envelope technologies can provide substantial energy savings, but current solutions such as electrochromic glass face barriers to adoption, notably high cost. There is a need for cost-effective commercial building window technologies to provide tunable heat control while ensuring visual comfort for occupants.


VG SmartGlass requested design assistance to optimize INVISIBLIND performance and to test and validate the product through demonstration. Additionally, the company sought guidance integrating its system with commercial building facades and lighting control systems. NREL support took the form of a product feasibility assessment. First, simulation using Radiance and OpenStudio software determined the energy impact potential of the current product version across a variety of building types and climates. Guidance on strategic applications given future design improvements was provided. In parallel, the NREL campus served as a demonstration location for the INVISIBLIND unit, enabling VG SmartGlass to evaluate product fabrication, installation, and ongoing maintenance in multiple window types and for different use cases.


Posted on

April 15, 2021