STTR Phase I: Autonomous Electrochromic Windows Enabled by Visibly Transparent Energy Harvesting Coatings

This Small Business Technology Transfer Phase I project explores an autonomous electrochromic (EC) window enabled by a visibly transparent photovoltaic coating technology. EC windows, which transition from a transparent state to a dark state (and vice-versa) based on an electrical input, represent a promising pathway to increasing building energy efficiency by effectively regulating the solar flux into the building. Though well-developed technologically, broad adoption of EC windows is limited by installation challenges rooted in a lack of autonomy (i.e. wiring to an external energy source, sensors, and control systems). The team has identified a key solution in which visibly-transparent photovoltaic coatings are integrated over the EC to serve as (1) an onboard energy source that harvests ambient light to power EC transitions, and (2) a photodetector that enables dynamic transparency control in response to changes in external lighting conditions. This project will demonstrate relevant performance and durability specifications of the photovoltaic coating to initiate large-area window integration and commercial deployment of autonomous EC windows. The broader impact/commercial potential of this project is embodied by unprecedented freedom for architectural EC window adoption, which can reduce electricity consumption for cooling, lighting, and peak power demands in buildings by up to 15%-50%. By integrating power and sensing functionalities onboard with the EC window without impacting visual aesthetics, a fully autonomous insulated glazing unit (IGU) can be constructed that requires no specialized installation or external balance of systems. Ultimately this will significantly broaden adoption of EC windows, by eliminating concerns related to the cost and complexity of EC installation, thus improving payback period and simplifying the decision-making process within the supply chain of the built environment. Moreover, this project will result in the development of knowledge that will guide future generations of visibly-transparent photovoltaics for other products in which a local energy source and light detection functionality can provide significant value (e.g. electronic displays and mobile electronic accessories), enhancing the functionality of those products without impacting aesthetics.