Windows play a crucial role in the overall energy efficiency of buildings. They allow natural light to enter and provide views to the outside world. However, traditional windows also contribute to heat gain, glare, and increased energy consumption for cooling. In recent years, researchers have been exploring the concept of dynamic windows, which offer the ability to switch between different modes to address these issues. A recent study has demonstrated a new material that expands the possibilities for dynamic windows, offering three modes: transparent, heat blocking, and tinted.
Dynamic windows based on electrochromism have been researched for some time. This technology allows windows to change their opacity in response to electric stimulus. Most dynamic windows developed thus far were limited to being either clear or dark, and researchers wanted to explore more options. Veronica Augustyn, a distinguished scholar in Materials Science and Engineering at North Carolina State University, led a team of researchers in developing a new material for dynamic windows.
The key to the development of this new material is water. The researchers discovered that when water is bound within the crystalline structure of tungsten oxide, forming tungsten oxide hydrate, the material exhibits a previously unknown behavior. Tungsten oxides have long been used in dynamic windows because they are normally transparent. However, when an electrical signal is applied, and lithium ions and electrons are injected into the material, it becomes dark and blocks light. The researchers found that by injecting lithium ions and electrons into tungsten oxide hydrate, they could effectively tune the wavelengths of light that are blocked.
The injection of lithium ions and electrons into tungsten oxide hydrate leads to two distinct modes of operation. Initially, the material transitions into a “heat blocking” phase, allowing visible wavelengths of light to pass through while blocking infrared light. This mode helps to keep the building cool while still allowing light into the space. With further injection of lithium ions and electrons, the material transitions into a “dark” phase, blocking both visible and infrared wavelengths of light. This mode provides complete privacy and glare control while maintaining the view from the window. The incorporation of water in the crystalline structure makes the material more resistant to deformation when the ions and electrons are injected, allowing for these dual functionalities.
The discovery of dual-band light control in a single material is a significant breakthrough in the field of smart windows. This new material with enhanced features could accelerate the development of commercial products. The ability to switch between different modes of operation offers building occupants more control over their environment and energy consumption. As energy efficiency becomes increasingly important in building design, dynamic windows have the potential to make a significant impact.
The research team’s findings open up new possibilities for the development of dynamic windows. By incorporating water into the crystalline structure of tungsten oxide, the material exhibits unique properties that allow for heat blocking and light control in a single material. This advancement brings us closer to the realization of highly efficient and customizable window solutions that can contribute to the energy efficiency of buildings. With further research and development, dynamic windows could become a standard feature in the construction of sustainable and environmentally friendly buildings.
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