| | How Electrochromic technology Work
Electrochromic windows consist of up to seven layers of materials. The essential function of the device results from the transport of hydrogen or lithium ions from an ion storage layer and through an ion conducting layer, injecting them into an electrochromic layer.
The electrochromic layer is typically tungsten oxide (WO3). The presence of the ions in the electrochromic layer changes its optical properties, causing it to absorb visible light. The large-scale result is that the window darkens.
The central three layers are sandwiched between two layers of a transparent conducting oxide material. To protect the five layers of materials, they are further sandwiched between two layers of glass. All of the layers, of course, are transparent to visible light.
 | A cross-section of an electrochromic window:
A voltage applied across the transparent
conducting oxide layers causes hydrogen
or lithium anions (A+) to be injected
into the electrochromic layers. |
To darken (or "color") the windows, a voltage is applied across the two transparent conducting oxide layers. This voltage drives the ions from the ion storage layer, through the ion conducting layer and into the electrochromic layer.
To reverse the process, the voltage is reversed, driving the ions in the opposite direction, out of the electrochromic layer, through the ion conducting layer, and into the ion storage layer. As the ions migrate out of the electrochromic layer, it lightens (or "bleaches"), and the window becomes transparent again. Technical Approach:
This project has two major complementary elements:
The first is the exploration and assessment of glazing performance in commercial buildings leading to development of design strategies that reduce unnecessary energy use.
Although the emphasis is energy impacts, e.g. annual energy use, the performance issues addressed in the guides and tools include all that impact the final glazing selection process, e.g. appearance, glare.
The second element is an exploration of daylighting strategies for commercial buildings since lighting energy use is the major energy end use in most buildings
Nanoshells can be chemically attached to a wide variety of materials, including plastics, liquids, aerosols, epoxies, glasses and even fibers.
New products could include energy-efficient smart windows, powerful solar collection and solar cells, coatings for cars, airplanes or buildings, biomedical sensors, and optical switches, steering light to different points in futuristic computer architecture. An additional by product of this research will be new concepts that can be applied in other parts of the spectrum such as the visible or ultraviolet.
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