Battery windows. Transparent solar panels

Relatively recently, innovative developments have begun to appear on the solar energy market that involve the use of window glass as solar panels. This is very promising technology, which can find application not only in urban high-rises, but also in many other industries. That being said, there are many companies working on the possibility of converting windows into battery windows.

Some propose installing thin strips of silicon photocells directly between the glass panes in double-glazed windows. By appearance Such battery windows resemble open blinds, as a result they do not block the view from the window. Others suggest using glass with a special translucent coating for windows. This layer is active; it converts light radiation into electrical energy, accumulating in special translucent conductors. Others suggest sticking a film on the glass that has the properties .

Device

Battery windows are currently available in two types: on flexible substrates and on glass bases. But there are other developments.

• Flexible options resemble tinting film; they are glued to transparent structures (facade glazing panels, windows, etc.). Their light transmittance is about 70%, which actually does not reduce the level of illumination in the room. They are made from flexible composite material, which is similar to plastic.

• Second option transparent panels involves applying a two-layer film to tempered glass. A thin film of amorphous silicon is deposited on a tempered glass substrate (in some cases triplex). A transparent silicon microfilm is sprayed on top of it. Microfilm converts infrared rays, and amorphous silicon converts the visible spectrum.

• A number of companies have decided not to create a completely transparent photovoltaic cell. Instead, they decided to go with a TLSC, which stands for Transparent Fluorescent Solar Concentrator. TLSC material consists of organic salts; it absorbs radiation from the infrared and ultraviolet spectrum, which is invisible to the eye, as a result it is converted into infrared waves of a certain length (they are also invisible). Specified infrared radiation goes to the edges of the plate where thin strips of photovoltaic solar panels are installed.
• The latest development by scientists is a completely transparent material that, when absorbing sunlight, can generate electricity. The material is a film of semiconductor polymer, which is saturated with carbon “balls” of fullerenes. The uniqueness of this material is that, under certain conditions, it forms an ordered structure that resembles a honeycomb when viewed repeatedly.

Operating principle

• Transparent films for windows contain an active luminescent layer. Small organic molecules absorb specific wavelengths of sunlight. In this case, it is possible to tune the structure to specific wavelengths. So these materials can absorb only ultraviolet and rays with almost infrared wavelengths, in order to subsequently “illuminate” a different wavelength in the infrared range.
• The "glowing" infrared light can be converted into electricity using thin strips of photovoltaic solar cells. Due to the fact that these materials do not emit or absorb light in the visible spectrum, they look absolutely transparent to the human eye.
• A completely new approach to creating a battery window is demonstrated by the technology of creating a material that creates electricity when it is irradiated. It happens like this:

Microscopic drops of water are directed through a thin layer of material that is in a liquid state.
As the polymer cools, the droplets are evenly distributed over the surface and evaporate.
The result is a texture of hexagons, their density is determined by the rate of evaporation and determines the efficiency of charge transfer. In other words, the tighter the packaging, the more effective the material.
The polymer threads are distributed along the faces of the hexagons. At the same time, they remain empty, and the material itself looks almost completely transparent. However, densely packed threads along the edges perfectly absorb sunlight and also conduct electric current, which is also created by irradiation sunlight material.

Peculiarities

• The main feature is already created panels consists in using the invisible spectrum of solar rays, that is, its ultraviolet and infrared parts.
• Absorption and “processing” of infrared radiation allows one to achieve an important advantage - minimizing thermal impact. This is extremely important for countries with hot climates. It is the IR spectrum of rays that leads to heating of surfaces and the need to cool them. Transparent solar panels absorb infrared rays without heating up. As a result, you can minimize costs for cooling systems.
• On this moment The developed technologies of transparent solar cells demonstrate low efficiency. But as technology improves, efficiency will increase. Even low productivity will pay off in the absence of the need to search for an installation location and ease of installation. A significant area of ​​glass structures, which actually do not bring practical benefit, will allow generating a significant amount of electricity.

Advantages and disadvantages

The advantages include:

• Ease of use, there is no need to look for additional space to deploy batteries, because they themselves are placed in the glass. They don't take up space.
• Ease of installation.
• Environmental friendliness.
• “Electric glass” takes away part of the light energy, as a result of which buildings heat up less. This allows you to reduce ventilation and air conditioning costs. This is especially true in countries with sunny and hot climates.
• Possibility of wide application.

The disadvantages include:

• Battery windows are not perfect and many of them take away part of the light that should enter the room.
• Low efficiency.
• Low prevalence.
• Lack of technology development.

Perspectives and Applications

Battery windows in the near future may well replace conventional glass in:

• Houses and other buildings.
• Electronic devices.
• Cars.

Some companies already produce glass in small quantities for installation in buildings, such as the Japanese corporation Sharp and a number of others. The possibilities for using such an invention are quite extensive, but the effectiveness of the technology is limited this moment limited by imperfect technology. Already proven technologies provide only 1%, and more advanced ones - 5-7%.

However, the prospects for transparent solar cells are vast. Thus, replacing the display of a smartphone or laptop with a new “solar” screen will significantly increase its operating life without recharging. Cities of the future could turn into green power plants without installation additional equipment— buildings will be able to supply themselves with energy.

As you know, classic solar panels are dark in color, either blue or almost black. Because of this, they often stand out very strongly against the background of the building, introducing noticeable dissonance into its architectural style. In addition, designers also have to take color features into account when developing modern energy-efficient buildings and small architectural forms. A solution to this problem was found not so long ago: scientists have developed transparent solar panels for facades and glazing systems.

The scope of application of transparent panels is very extensive:

• Glazing of facades;
• Construction of winter gardens;
• Construction of greenhouses and livestock complexes;
• Glazing of pavilions;
• Creation of glass roofs and courtyards (atriums);
• Glazing of attics and penthouses;
• Creation of various types of sun protection systems (over recreation areas, swimming pools, etc.).

The main feature of such panels is the use of the invisible spectrum of solar rays, its infrared and ultraviolet parts. At the same time, the absorption and “processing” of infrared radiation has another advantage - minimizing the thermal impact. The fact is that overheating of photo panels, due to which they need additional cooling, it is the IR spectrum that causes. Transparent models absorb IR rays, and they do not heat up the panels themselves. This means that it becomes possible to abandon cooling systems and reduce the overall cost of installing a heliofield.

Design nuances

Currently, transparent panels are produced in two types: on glass bases and on flexible substrates. Flexible options resemble tinting film and are designed for gluing to transparent structures (windows, facade glazing panels, etc.). Their light transmittance reaches 70%, which actually does not affect the level of illumination in the room. They are created from a flexible composite material similar to plastic. The use of modern developments allows us to minimize the costs of producing such films and make their production economically profitable.

The second option for transparent panels is applying a two-layer film to a base made of tempered glass. These types of panels are used for the construction of facades. A thin film of amorphous silicon is applied to a tempered glass substrate (often triplex) latest generation. A transparent silicon microfilm is sprayed on top of it. Amorphous silicon converts the visible spectrum, and microfilm converts IR rays.

Moreover, thanks to the use of special dyes, scientists were able to give transparent facade panels almost any shade. This means that with the help of such batteries you can create any façade compositions. In addition, developers actively use organic dyes with photoelectric properties in transparent panels.

This technology allows you to increase the efficiency of the product, while simultaneously giving it the desired color. The organic dye is supplemented with nanocomponents, placed between two glass substrates, and the joints are filled with glass powder. Then the resulting “sandwich” is baked at temperatures of about 600°C. The result is a silicon-free photopanel with an efficiency of about 4%. True, the cost of such products still exceeds the economic benefits of their mass production.

Performance of transparent panels

Despite a lot of advantages, transparent facade panels also have some disadvantages that so far prevent their widespread distribution. The main limitation is low productivity. The efficiency of such products is still only slightly more than 1%. However, scientists lead active work to improve energy production and expect to increase the efficiency to 5% in the near future. This will be enough to get started industrial production and the introduction of transparent facade panels.

Low productivity will pay off with ease of installation and no need to search extra space installations. Ultimately, the cost of installing such panels will be no more than the cost of placing conventional silicon photo batteries. A significant area of ​​glass structures (which in their in the usual form, in fact, do not bring any practical benefit) will allow them to generate quite a noticeable amount of electricity.

Another promising direction, possible with an increase in efficiency, is the use of such “photoglasses” in the screens of laptops, tablets, smartphones, etc.

Ecology of consumption. Science and Technology: Transparent solar panels, which can be used as windows, represent a huge source of untapped energy and can provide more energy than rooftop solar panels.

Transparent solar panels that can be used as windows represent a huge source of untapped energy and can provide more energy than rooftop solar panels.

The study authors argue that the widespread use of such highly transparent solar panels together with rooftop solar systems, could meet U.S. electricity demand and dramatically reduce the use of fossil fuels.

“Highly transparent solar cells represent a new wave in solar energy" said Richard Lunt, a research fellow at the University of Michigan state university(MSU). “We analyzed their potential and demonstrated that by harvesting only the invisible spectrum of light, these devices can provide the same power generation potential as rooftop solar, improving the efficiency of buildings, cars and mobile electronics.”

Lunt and his colleagues at MSU have pioneered the development of a transparent fluorescent solar concentrator that, when placed on a window, generates energy without affecting the transparency of the glass. The thin plastic material can be used on buildings, car windows, cell phones or other devices with a transparent surface.

Such a system uses organic molecules developed by Lunt and his team to absorb invisible wavelengths of sunlight. Researchers can “tune” these materials to collect only ultraviolet and infrared waves, which then convert that energy into electricity.

Changing global energy consumption and moving away from fossil fuels will require just such innovative and cost-effective renewable energy technologies. Only about 1.5% of electricity in the United States and worldwide is produced by solar energy.

But from another point of view, the United States has a huge potential for generating electricity using this technology - from 5 to 7 billion square meters glass surfaces. And with so much glass, transparent solar technology could supply about 40% of the U.S.'s electricity—about the same potential as rooftop solar. “The active implementation of both technologies can cover 100% of electricity needs, but with the condition of improving energy storage technologies,” Lunt said.


High-transparency solar panels have an efficiency of about 5%, while traditional solar panels typically have an efficiency of 15 to 18%. While transparent solar technologies will never be more efficient than their opaque counterparts, they have enormous potential for application on all available glass surfaces.

Current transparent solar technologies are developed at only a third of their real potential, Lunt added.

"That's what we're striving for," he said. “Conventional solar panels have been actively researched for more than five decades, but we have only been working on these transparent solar cells for about five years. This technology offers a low-cost, widely applicable way to convert solar energy on small and large previously inaccessible surfaces.”

Researchers from the University of Michigan have achieved complete transparency of solar panels. This advancement makes it possible to turn any window or screen surface (like your smartphone) into a solar photovoltaic cell. Unlike previous designs that were previously reported, this battery option is almost completely transparent, as you can see by looking at the photo above.

Research leader Richard Lunt said that there is confidence that such solar panels can actually be used in a very wide range: from high-rise windows to screens mobile devices, such as a phone or an e-reader.

From a scientific perspective, a transparent solar panel is something of an oxymoron. Solar cells, operating on the principle of the photoelectric effect, absorb photons (sunlight), then converting them into electrons (electricity). But if the material you see is transparent, it means that sunlight was not absorbed but passed through it to reach the retina of your eye. It was this moment that developers could not bypass before, trying to create completely transparent solar panels. They (the batteries) were partially transparent, and, on top of that, as a rule, had rainbow stains.

To solve this problem, researchers at the University of Michigan used a slightly different technology for collecting solar rays.

Abandoning attempts to create a completely transparent photovoltaic cell (which is almost impossible), they used what is called a transparent luminescent solar concentrator (TLSC)

TLSC is a material consisting of organic salts that absorbs ultraviolet and infrared radiation invisible to the eye, which is then converted into infrared waves of a certain length (also invisible to the eye). The resulting infrared radiation is directed to the edges of the plate, where thin strips of conventional photovoltaic solar cells convert it into electricity.

If you look closely, you will see black stripes on the cut of the plastic sheet. Thus, because organic material makes up the majority of the solar panel, it is highly transparent.

Today, the efficiency of Michigan TLSC plastic is 1%. However, according to scientists, it is likely that it can be increased to 5%.

Similar opaque luminescent concentrators (filling the room with rainbow light) have a maximum efficiency of 7%. In themselves, these numbers are not huge or impressive, but on a large scale - for example, when used in every window of a home or office, the figure quickly increases.

In addition, until the technology is developed to keep your smartphone or phone running continuously indefinitely, replacing the device's display with a TLSC screen can increase its battery life by several minutes or hours on a single charge.

The developers are confident that the technology can become widespread: from use on a global industrial scale to the domestic home level. Until now, one of the biggest obstacles to the widespread use of solar panels has been their bulkiness and unaesthetic quality. Obviously, if it becomes possible to convert sunlight into electricity using sheets of glass or plastic that are no different from ordinary ones, the use of such solar panels will be versatile.

Windows let light into the house, and with it the warmth of the sun. There are many technologies for passively controlling light from windows in order to reduce or increase the amount of incoming heat. But this heat is essentially energy, which theoretically can be converted into electricity. Scientists from the US Department of Energy have developed a transparent solar film that will turn windows into environmentally friendly power generators.

It is clear that for maximum effective use Solar energy collectors should be located in places of direct contact with the sun's rays. Until now, only the roofs of houses were considered such. New development will allow expanding the use of solar technologies on the surface of windows.

A joint development by scientists at Brookhaven National Laboratory and Los Alamos National Laboratory, it is a transparent thin film that can absorb light and generate an electrical charge. The material, described in the journal Chemistry of Materials, could be used to create transparent solar panels or even windows that absorb solar energy and generate electricity.

The new material consists of semiconducting polymers with the addition of fullerenes - molecules consisting of six carbon atoms. Subject to strict compliance with the conditions technological process the material self-structures, creating a repeating pattern of micron-sized hexagonal cells over a relatively large (several millimeters) area (a structure originally characteristic of fullerenes).

“Such thin honeycomb films have already been created from ordinary polymers like polystyrene, but our material is the first to combine semiconductors and fullerenes, which gives it the ability to absorb light, as well as efficiently generate and separate electric charges“,” noted Mirce Cotlet, a physical chemist at Brookhaven’s Center for Functional Nanomaterials (CFN).
In addition, the material remains almost transparent, since when fullerenes are added, the polymer chains line up along the edges of micron-sized hexagons, and in the center their layer remains loose and very thin. As Kotlet explained, the denser edges of the hexagons absorb light more strongly and can help conduct electricity, while their central part is relatively transparent and therefore absorbs very little light.

“The combination of these features while achieving large-scale structuring will make it possible practical use technology, for example to create energy-generating solar windows, transparent solar panels or new types of displays,” said Zhihua Xu, a materials scientist at CFN.
To produce solar cellular film, scientists passed a stream of tiny (micron) drops of water through a thin layer of a mixed solution of polymer and fullerene. In the polymer solution, these water droplets self-organized into large matrices. After complete evaporation of the solvent, the polymer took the form of a hexagonal honeycomb lattice quite large area. According to the developers, this method is effective enough to be used not only in laboratory conditions, but also on an industrial scale.

Scientists checked the uniformity of the honeycomb structure using various methods scanning and electron microscopy, and also tested the optical properties and efficiency of charge formation at different parts of the honeycomb structure (at the edges, in the center of cells, at the intersection of individual cells) using time-controlled confocal fluorescence microscopy.
It turned out that the degree of polymer compaction is determined by the rate of solvent evaporation, which, in turn, affects the rate of charge transfer through the material. The slower the solvent evaporates, the denser the polymer is and the better the charge transfer.

“Our work allowed us to gain a deeper understanding of the optical properties of the honeycomb structure. The next step is to use these thin honeycomb films to make transparent, flexible and environmentally friendly solar cells and other devices,” concluded Mircea Cotlet.