Due to the heat transferring properties of windows, efforts to improve energy efficiency have been ongoing. Over the past decades, many of these efforts proved successful. For example, it is reported that the Empire State Building in New York saved $2.4 million after installing smart windows.
As building codes tighten across the country, energy-efficient windows become more of a requirement than an extra. Smart consumers understand the benefits, including a more comfortable living space and long-term cost savings. They want – even expect – every energy savings measure to be taken. According to the US Department of Energy, buildings account for more than 40% of the energy consumption.
Any scientific advancement that would reduce this consumption would be welcome by consumers and environmentalist.
Reflective Window Technology Breakthrough
There has been a breakthrough in energy-efficient windows technology. A doctorate student at the Eindhoven University of Technology has developed a technology that allows visible light to pass through glass while blocking the invisible infrared spectrum.
Two advancements make this energy-saving technology different from what has previously existed:
The Glass Remains Clear
The first new important feature is that the glass remains clear. The transparency is nearly 90%, which is similar to double glazing.
Currently, windows that filter light tend to be dark or discolored, blocking out much of the visible light that produces brightness in a home, car and greenhouse. A special feature of Hitesh Khandelwal invention allows the windows to remain clear while still reflecting out the unwanted invisible spectrum that does not aid in visibility but does contribute to warming the air inside the window.
The Sun Blocking Feature Can be Turned On and Off
The second innovative energy-saving feature in this new technology is that the blockage can be turned on and off with a switch. This allows users to block much of the heat-generating sunlight in the summer, reducing air conditioning costs. In the winter, when the feature is turned off, the invisible spectrum is allowed to pass through the glass bringing its heating properties into the building, reducing heating costs.
The blocking feature can also be switched on and off automatically with a timer. The house can maintain a steadier temperature by setting the timer to block the hot summer sun in mid-day. The timer can be set to switch off the blocking features in the evening.
A smart home can take this automation a few steps further. The blocking effect can be turned on and off using a temperature sensor. Or, an owner of a smart home can turn it on and off remotely using his computer and internet connection.
This advancement will allow energy consumption to be reduced by 12%.
How the New Technology Works
Khandelwal’s development uses organic liquid crystals on double pane windows. When an electric charge is sent through the crystals, they align in such as way as to block out the invisible light but not the visible light. These crystals are similar to those used smartphones to selectively block certain light waves.
The crystals on these smart reflective windows block nearly 100% of the light waves in the infrared, invisible range, specifically the 700 nm to 1400 nm wavelengths. Although this range is invisible, it contains nearly 50% of the energy from the sun.
For Use on Existing Windows
The inventor has developed a prototype that can be applied to existing windows. When marketed, this will prove valuable with cars, greenhouses and buildings already in use.
