In the heat of summer, office and residential buildings are usually controlled by air conditioning, energy tax increases. In fact, it is estimated that air conditioners use about 6% of the electricity generated in the United States at an annual cost of $ 29 billion, which, of course, increases in the global thermometer level.
Now MIT engineers have developed a heat refining film that can be used in a window that reflects 70 percent of the incoming heat of the sun. The film will be able to be maximally transparent at 32 degrees, or 89 degrees Fahrenheit. At this temperature, researchers say that the film calls the "autonomous system" to deny heat. They believe that if all the windows built in this renovated window were built, the building's conditioning and energy costs decreased by 10%.
The film is similar to transparent plastic rolling and its heat-rejection features from small microphones involved in it. These microprocessors are made from phase variable material, which is reduced when 85 degrees Fahrenheit or higher temperature conditions. In more compact configurations, microprocessors normally provide transparent film more transparent or frost.
In the summer the windows are appealing, the film can keep the building smoothly when it's good. Professor of MIT Mechanical Engineer Nikoloz Pang says that the material implies the existing and energy efficient alternatives of smart window technologies.
"Smart windows are not currently on the market or are not very effective at solar heating, or, like electrochromagnetic windows, they have more power to manage them, so you pay for windows openly," said Fang. "We thought we could have new optical materials and insulating rooms to ensure better smart window options."
Fang and his colleagues, including researchers from Hong Kong University, published magazines Julie.
"Water Bottle Water"
A year ago, Fang started cooperation with researchers at the University of Hong Kong, who expressed their willingness to reduce the energy consumption of city buildings, particularly during the summer months when the region is increasingly hot and air-conditioned.
"The meeting with this challenge is critical for such a metropolitan area, such as Hong Kong, where there is a strict time frame for energy saving," says the phantom, which means Hong Kong's commitment to reduce its energy consumption by 40% by 2025.
After a few quick calculations, Phang students discovered that a significant part of the heat of the building comes through a window through the sunlight.
"It turns out that on every square meter, about 500 watts of energy in the heat of the heat is limited to the sun through the window," Fang says. "It's about five lamps."
Fang, whose group studies the luminous properties of exotic, phase-replacement materials, is interested in whether or not such optical material is placed in the window, passively reflects a significant part of the incoming heat of the building.
Researchers have provided evidence for materials for thermochemistry – sensitive materials that temporarily change the phase or color in response to heat. They finally came from polyester (N-isopropylcararlide) -2-aminethylethylactylate hydrochloride microprocessor. These microprocessors look like a small, transparent, fiberglass fabric and filled with water. In the conditions of 85 F or higher, the fields mostly cut off all their waters and reduce the fibers of the fibers which reflect the transparency of the transformation material.
"It's like a water bottle," said Fang. "Each of them gives the fibers a certain light, but because the fish in the high place of fish, each of the fibers is more difficult, but once more water is warmed."
In previous experiments, other groups discovered that when champagne particles were relatively lightly denied, they were less successful than heat. Fang and his colleagues realized that this limitation was on the particle size: the particles were previously used for about 100 nanometers in diameter – less than the infrared light wavelength, which got the right way of heat.
Instead, Fang and his colleagues expanded the molecular chain of each microprocessor, so that when the heat was replaced, the diameter of the particle was about 500 nanometers, which said Fang is "closer to the infrared spectrum of the sunlight."
Researchers have created a heat-protecting microprocessor that was used on a 12-by-12-inch glass sheet to create a film-covered window. They moved from the solar panel to the window of the sunlight, and found that the film was frozen in response to the heat. When they were on the other side of the window, the researchers found that 70 percent of the heat produced by the film was rejected.
The team set up a small calorimetric chamber with a heat-negative film and assessed the temperature in the chamber as they moved from the sunlight to the light through the movie. Without the film, the internal temperature is heated about 102 F – "the temperature of high fever," Fang notes. In the inner room of the film is more convenient 93 F.
"It's a big difference," said Fang. "You can make a big difference in comfort."
To move forward, the team plans to conduct more tests on the film, how much tweaking its formula and other ways of application can improve its heat-protective properties.
This research is financed by partially by the HKUST-MIT Consortium.