Dark glasses: Soladigm demonstrates an electrochromic window at its headquarters in California. An electric current has been applied to the pane on the left, limiting the amount of light and heat that can pass through.
Soladigm
"Tunable" windows would let people adjust light and heat levels, but so far it's been hard to make them affordable.
Windows that absorb or reflect light and heat at the flick of a switch could help cut heating and cooling bills. A company called Soladigm has developed methods for making these "electrochromic" windows cheaply, making them more viable for homes and office buildings.
Existing electrochromic window designs cost around $100 per square foot. Soladigm has not disclosed how much its windows will cost, but some experts say the method could reduce the cost to around $20 per square foot.
The Milpitas, CA-based company uses a thin-film deposition process that creates conducting layers between two panes of glass for controlling the amount of sunlight and heat that can pass through. A homeowner or office dweller could control how much light or heat a window lets in or absorbs and reflects.
The company's windows contain two transparent conducting oxide films sandwiching an ion storage layer, an electrolyte, and an electrochromic layer--all between two layers of glass. Applying a low voltage to the conductive oxide kicks the ions out of the storage layer and across the electrolyte to meet with the electrochromic layer. The collision prompts the electrochromic material to absorb or reflect light. It also causes the material to darken, giving the window a tinted look. Reversing the voltage sends the ions back to its storage layer, causing the window to lighten in color and let more light in.
"We did a case study in five cities, and the average savings in commercial buildings are about 25 percent of the heating, ventilation, and air-conditioning energy use annually," says Rao Mulpuri, CEO of Soladigm.
The trick to making electrochromic windows cheaply is the right materials and latest manufacturing method, says Mulpuri. Today's thin-film deposition equipment--the same used to make flat panel display and thin-film solar panels--is much better than that used a few decades ago, when the electrochromic window concept emerged.
Soladigm will use a tungsten oxide-based electrochromic layer for its first windows. Tungsten oxide can endure repeated cycling between ion-rich and ion-free stages-which makes it durable, says Delia Milliron, a Lawrence Berkeley National Laboratory (LBNL) researcher in electrochromic materials. However, using tungsten oxide can heat up a window until it's too hot to touch; it also doesn't block infrared light very well, meaning it lets plenty of heat through.
The company says its future is in energy products for the Chinese market.
Where this is most useful is in cars. The massive cost of a vehicle which is replaced in full allows those people who replace cars fairly frequently to add this tech into the vehicle pool much faster than these windows can be added to the home pool.
If the windows are designed to black out whenever the car is turned off, it functions as both a security measure (no one will notice if you forgot your laptop on the passenger seat) as well as an energy conservation/cooling measure. Keeping the car cool means less AC use when the car is restarted and more comfort for occupants. When running, it can be designed so that it is impossible for the window to be turned dark again, but the heat is still adjustable by the driver for AC efficiency in the summer or heating efficiency in cooler times.
When will this make a debut in vehicle glass?
Yes vehicle and military applications might be worthwhile considerance as well as extreme architectures; space and arctic bases
cheap but other options available now
The average homeowner probably won't be able to afford smart windows until the market becomes saturated. There are things like window tint that are affordable and can be purchased an installed by regular folks like myself. We got some affordable window tint kits from SnapTint to cut down on the glare and heat coming in our western facing windows. They work asa advertised and have helped keep the room cooler and AC running less. Check out their website if your interested in something to save on your electric bills now.
The smart windows should also be smarter than birds so that birds do not fly into them. This happens to be one of the main causes of bird losses in places such as New York that are along a major migratory bird route.
Manufacturing in the United States is in trouble. That's bad news not just for the country's economy but for the future of innovation.
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mattgroom
284 Comments
light, heat...and
Whats that i hear you say?
Cheap is just a start. There have been many incredible building improvements over the years and yet we dont see many of them in new housing.
I remember the day..i don't really...but in olden japan if a house was made badly or collapsed the builder was executed. I wonder how many builders would be executed if they lived back then.
The only benefit today is the roof has additional insulation.
The "foundations" and building of houses over 100 years ago far surpass todays buildings which crack easily.
At this slow rate its possible in another 100 years those windows will be used in new housing...
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rsanchez1
213 Comments
Re: light, heat...and
It may take 100 years for the housing market to pick up again. The housing sector is very stagnant right now and doesn't look like it will pick up steam for a long time. Without the incentive, builders won't build new houses. Without new houses, these windows won't be implemented. The only way to get these in every house would be through government regulation, which could be imposed on new house construction, but good luck getting homeowners struggling to keep their homes to fit the bill.
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