Using Glass To Generate Electricity

At the end of 2019, Ubiquitous Energy's employees in Sequoia, California, United States gathered in a meeting room composed entirely of glass windows.The new glass windows in front of them not only showed the spectacular mountain views and beautiful sky of northern California, Can also be used as photovoltaic cells to provide energy for the company's lighting, computers and air conditioners.

After years of research and development, the company has achieved a technological breakthrough-power generation glass, the secret of which is the multiple organic polymer layers added between the glass sheets, some of which can completely transmit light, while others can absorb Invisible infrared and ultraviolet. When light passes through the glass, the electrons between the polymer layers form a current, which is collected by the thin wires in the glass.

"This is a bit like a transparent computer monitor running in reverse." Position generates current.

At present, at a given light level, the power generation capacity of this glass is about one-third that of conventional roof photovoltaics, and its light transmittance is about half that of ordinary glass.

Hardev said that meeting these indicators is enough to make this glass a practical product, and his company is expected to significantly increase the light transmittance of the glass. As for the lower power generation efficiency, he pointed out that the area covered by the window is larger than that of the roof, so the area advantage can be used to make up for the lack of efficiency. "You can use both, but the windows will generate more power." He added that the biggest challenge is how to expand the window area currently less than 0.19 square meters to about 4.65 square meters.

Clearer Than Glass

The revolution in windows is long overdue. As the world's major cities regain their love for skyscrapers, the glittering high-rise buildings have evolved into fixed attractions everywhere, but the glass on the high-rise buildings has made little technical progress.

Controlling the temperature of buildings is a huge challenge. 18% of funds in the US energy project are used to heat and cool buildings. According to Lawrence Berkeley National Laboratory's estimation, in the cold season, the heating value lost from the windows is equivalent to about 20 billion US dollars; in summer, the cooling value lost from the windows of air-conditioned buildings is greater. In short, more than half of the funds used for heating and cooling of buildings is wasted by the loss through windows.

Michigan-based Mackinac Technology is developing a coated plastic sheet that can be placed on the surface of ordinary glass to improve the thermal insulation and heat reflection properties of the glass without affecting the clarity of the field of view. Among them, the plastic plate traps the air in the middle and improves the thermal insulation performance of the glass. The coating allows visible light to pass through, but reflects infrared light (carrying most of the thermal energy). The company's CEO John Slagter said that the invisible coating reduces the amount of light reflected from the plastic surface, which instead increases the amount of light transmitted through the window and the clarity of the room.

Installing a coated plastic sheet directly on an existing window frame can double the thermal insulation performance of single or double glazing, and it is very light and does not significantly increase the weight of the window. Slagter said the new material has successfully passed tests on windows at Calvin University. Thanks to partial funding from the US government agencies, the plastic sheet will be tested in larger pilot projects before it is officially put into use in 2022.