Thermoelectric power generation showed great potential - pure sine wave inverter 5000w

Imagine, in the near future, to capture solar energy, no longer need expensive panels, just buy a few barrels of paint, painted on the roof, walls or any contact with the sun's surface, you can turn them into a huge solar energy solar panels.

One way to reduce electricity costs is to use ubiquitous free energy - sunlight. But first of all, you have to come up with a lot of money, experts come to your house to install heavy and inefficient solar panels on the roof. Now, there is a method of high-power inverter can use free solar energy, and do not have experts, do not have to spend big money to buy solar panels. If you only need to buy a bucket on the shop paint, spend an afternoon to paint the roof to buy their own new paint, and then please an electrician to connect the roof on the wire, you can make your home completely out of the grid to achieve energy self-sufficiency?

This is the promise of a new solar material promise. This material uses the temperature difference between the two sides of the material to produce current, once because of the efficiency is too low, expensive, is considered difficult for practical applications. But the new study found that thermoelectric power generation materials can save the solar energy industry, to solve the deadly light-electricity conversion efficiency of the panel. Thermoelectric generation materials can help solar panels out of the trough, play a greater use, but on the other hand, they may also lead to the decline of the battery.

As early as half a century ago, people have begun to dream of thermoelectric power generation materials and solar materials combined. In 1954, solar pioneer Maria Turks with a thermoelectric power generation materials to absorb solar heat, and the success of heat energy into electricity. Material side of the thermal energy to release the electron flow to the lower side of the temperature, resulting in a high temperature side of the positive, the lower the temperature side of the negative. Turks succeeded in generating the current in this way, but only a little. The efficiency of photo-electricity conversion is very low, the most successful one-time experimental conversion rate is only 1%, which is the silicon solar panels at the time the efficiency difference is not much. However, by the end of the 1950s, the efficiency of silicon solar cells doubled to 6-8%, while the efficiency of solar thermal power generation materials remained at 1% .Therefore, the nascent solar industry quickly abandoned this Technology, vigorously develop silicon solar panels. 70 to 80 years of the last century, a large number of silicon solar panels began to appear on the roof.

In the next few decades, thermoelectric power generation materials are almost completely ignored. In addition to poor power generation efficiency, this material itself - the raw materials are usually used bismuth telluride and other rare elements - expensive, relative to humble output is not worth. Only in extremely rare cases can they be adopted without any other choice. For example, in the "Traveler" space probe, the thermoelectric power generation material using a small piece of radioactive material and the cold outer space temperature difference for the detector to provide power.

Photovoltaic panel intelligent cleaning robot However, shortly after the development of silicon solar panels also suffered bottlenecks. Although the researchers tried every means, today the sale of photovoltaic solar panels efficiency is still between 15% to 20%. This is related to how they convert sunlight into electrical energy. When the light irradiation solar cell surface, a part of the photon absorption by the silicon material; photon energy transfer to the silicon atoms, so that electrons move to form the current. But the problem is that the photon must carry the right amount of energy. Exceeding this energy range can cause problems. If the photons carry too much energy - such as the energy carried by high-energy ultraviolet light - their heat can cause material chaos. On the other hand, if photons carry too little energy - such as photons of microwaves or infrared light - to pass directly through the panel, they do not react with any electrons.

Unfortunately, these low-energy photons account for nearly half of the solar spectrum, so the efficiency of solar panels can not exceed 50% .Worse still, high-energy photon photovoltaic materials will cause damage to the electronic structure: under high heat electron Began to scurry around, rather than orderly flow. Therefore, about half of the solar photons can not be used, a small number of energy sufficient photon but will affect the efficiency of the panel. Although the side effects of overheating of the panels can be reduced by cooling. But this will lead to cost and volume increases, the cooling process also need to consume energy, constitute a limit photovoltaic solar panels efficiency of the three enemies.

Perhaps with thermoelectric power generation materials to help solve these problems? In 2007, Chen Gang of Massachusetts Institute of Technology began to think whether to re-excavate this has long been neglected materials, solar cells to help make full use of a variety of wavelengths of sunlight.

This is a tempting idea. Theoretically also been confirmed. Combined with thermoelectric power generation materials and photovoltaic materials, solar cells can divert high-energy photons, thereby cooling the battery, and the thermoelectric power generation materials can capture low-energy photon power generation, make full use of all the sun.
Theoretically, the best way to combine the two materials is "split-spectrum solar cells." It is similar to traffic (here xx instead, you know), according to the wavelength of the sun will be separated. According to Chen's calculations, similar to the efficiency of hybrid silicon solar cells will be standard 1.5 times, such a leap may eventually make solar energy prices in competition with fossil fuels. But there is the question: "To achieve 'spectral splitting' requires a solar concentrator and a dichroic prism." The added cost is already higher than the efficiency gains.

Perhaps a better choice is a simpler thing. Instead of building a complex structure to divert low-energy photons, why not let them go straight through the solar cell into the underlying thermoelectric generation layer? And then the following cooling pipe can absorb the high-energy photon heat. The hot plate and cold water provide the ideal temperature difference for the thermoelectric power generation layer in the middle. But even so, the excess energy captured by the thermoelectric power generation layer is still insufficient to cover the cost of the material. Must solve the most fundamental problem: thermoelectric power generation materials are expensive prices.

Its power generation is also the culprit leading to inefficiency. As the material heats up, the electrons move away from the atom and migrate to the cold side. Difficulty is to maintain the temperature difference between the two sides of the material. The electron is not the only thing that penetrates the material: heat travels in the form of photons, passing from one atom to another. The cold side will soon heat up because of heat conduction, this time, the electron will no longer flow in a particular direction, but disorderly scurrying. Of course no longer generate electricity.

In half a century, this problem has not been resolved. Until the emergence of nanotechnology. Now, researchers can control the structure of the material from the finest levels.

In the crystalline material such as silicon, all the atoms are arranged in an orderly manner. So that electrons and photons can be unimpeded through. On the other hand, in a material such as a glass or the like having a disordered arrangement of atoms, the flow of electrons and photons is hindered. Nanotechnology allows the creation of synthetic materials that allow only electrons (rather than photons) to pass through. Yin Huiming and Yang Dajiang of Columbia University in New York used a quantum dot base material. Quantum dot materials were born about 30 years ago, like traditional solar cells, it can capture light energy, into electricity. It can make the efficiency of ordinary thermoelectric power generation materials close to double. Caught in the middle of the water-cooled photovoltaic power generation system, this material can improve the efficiency of solar cells to more than 50%.

Charles Stafford of the University of Arizona, in creating a similar device in the process realized that there is a possibility, it may even reshape the entire solar energy industry. If you can completely abandon the critical of the photovoltaic cells? If you can find a high-efficiency solar capture material, which completely replace the solar cells? If it is cheap enough, it does not matter if its peak efficiency is less than 50%.

To this end, he must abandon the semiconductor, looking for a new material. He found a polymer called polyphenylene ether may meet the requirements. "They're cheap," he says, "and you can buy a few cans and brush on any surface that can be sunlit." Stafford says he can process the molecules of the material and interfere with the flow of photons, Electrons through. He estimated that this new material can be 20% to 25% of the photons into electricity, the efficiency of today's thermoelectric power generation materials 6 times. If he succeeds, the results will be staggering. Photovoltaic solar cells may be eliminated from this.

Many researchers have seen the prospect of solar coatings. Canadian nanotechnology researcher Ted Sargent years ago began to study solar energy coatings. The key material in his paint is also the quantum dot. The biggest advantage of this coating is the low price. Covering 1 square meter of film only need 15 to 20 dollars. When making coatings, heat the industrial olive oil first, then add the main raw materials - tin, bismuth, lead, sulfur and selenium - and wait for the quantum dot to form. The finished product is like an oily black ink, but there are quantum dots that are several nanometers across and each is a small crystal. Sargent's team in 2005 proved that quantum dots not only capture the energy of visible light, but also capture the energy of infrared light, and half of the solar energy arrived in the Earth is carried by infrared light. Sargent's solar technology is not yet mature, but has attracted to the rich and poor investors. King Abdullah University of Science and Technology (KAUST) is one of the few schools in the Arab world that has invested heavily in attracting the world's top talent. Sargent has been working with KAUST since 2008. KAUST has invested $ 10 million in his research. And access to this technology in the Middle East, West Asia, Russia, India and other 38 countries the right to use.

University of Notre Dame researchers in solar coatings research also made a breakthrough. They created a kind of semiconductor nanoparticles capable of producing electrical energy. "We want innovation to move away from today's silicon-based solar technology," said Pratacam Carter, a professor of biochemistry at the University of Notre Dame's Center for Nanotechnology for Chemistry and Photovoltaics. "By combining nanoparticles and a smearing material , We have created a solar coating that can be applied to any conductive surface. "

The research team after repeated trials, and finally selected the titanium dioxide nanoparticles, wrapped in cadmium sulphide or cadmium selenide, and finally add water and alcohol, forming a paste. Smear on a transparent conductive material, exposed to sunlight, can generate electricity. "The best optical-to-electrical conversion efficiency is now only 1%, well below the 10 to 15% of silicon solar cells," explains Karte, "but the cost of this coating is low and can be mass-produced, Optical-to-electrical conversion efficiency, we may be able to change the way the future of energy access. "

In fact, this day may be in sight. In May 2011, Chen Gang published a paper, indicating that solar panels without solar power systems will soon become a reality: This is because the thermoelectric power generation materials provide a new way of gathering solar energy. Until now, small-scale roof solar panels still can not achieve this. Because the gathering sunlight requires a complex lens system to track the sun's trajectory, it is too expensive to use only commercial-scale solar power stations.

However, the gathering sunlight is very simple, a piece of copper into the sun can be done. The copper into the cheap glass vacuum cover, can be trapped in the heat within the cover, only need to be a small piece of thermoelectric power generation material attached to the back of the copper can be heat into electricity. Even with the use of conventional thermoelectric generation materials, the photoelectric conversion efficiency can reach an unprecedented 5% .If the material cost is low enough, even if such efficiency is worth producing. If the efficiency of thermoelectric power generation materials has increased, photovoltaic solar cells may soon be replaced.