First, the characteristics of solar energy

As a new solar energy and conventional energy sources such as fossil fuels (coal, oil, natural gas) and fuel, compared with many unmatched features.

1, solar energy directly or indirectly as energy, human play a very important role: One of the advantages is that it continued to supply a steady flow. Scientists concluded that the life of the sun a few billion years can be considered, solar will be inexhaustible. Therefore, it generated by the solar and other forms of energy are called renewable energy.

2, extensive solar energy: solar energy everywhere, locally available, in the mountains, deserts, islands and other remote areas of the superiority of the more obvious people as long as one-time investment in power generation equipment installed, the average cost of maintaining smaller than other energy sources so much solar energy affordable.

3, solar energy is scattered features: solar radiation, despite the global, but the power per unit area is small, so to get more power, there must be a larger area by the light, which makes equipment, materials, structure, increase the cost of occupying land, thus affecting the popularization and application.

4, solar energy is clean and nature: using solar energy, not emissions, waste, pollution, therefore, solar energy is known as clean energy, green energy.

Regional solar energy: near the equator, the sun is direct ground in the noon time, and therefore greater strength. In the polar regions, the sun seemed to glide like a slanting surface, which in the unit area received less sunlight, the intensity was also smaller. In addition, the time when the sun slanting through Lenovo N100 battery the thickness of the atmosphere than the direct time, it consumes heat in the atmosphere have more, get less of on the ground. Because of these two reasons, the Earth is divided into tropical, temperate and boreal, their order is the equator to the poles gradually change.

Intermittent solar energy: the sun’s elevation angle for a day and constantly changing within a year, plus the climate, the seasons change, the amount of solar energy can be very unstable, very random. In addition to use of solar power generation and power generation, in general, must have a considerable capacity storage devices such as batteries, etc., which not only increase the equipment and maintenance costs, but also limits the power scale.

Second, solar energy use Method

Advantage of the sun, there are three methods:

The sun’s radiant energy into heat energy, called solar thermal conversion;

The sun’s radiant energy into electrical energy, called the photoelectric conversion;

The sun’s radiant energy into chemical energy, called photochemical conversion.

1. Photothermal conversion: This method is the use of solar collector or concentrator to be 100 degrees below the low temperature heat source and heat source temperature 1000-4000 degrees. It is more common application of an approach is widely used in cooking, drying grain, supply hot water for indoor heating, air conditioning, sun

Thermal power generation, the output mechanical compaq mini 700 battery energy and heat treatment and so on. Direct use of solar radiation in agriculture example is the solar greenhouse and solar water pumps. In addition, solar energy can also be used in desalination and so on.

High temperature solar furnace is a rare high-temperature heat source of impurities, can be used in scientific research and metallurgical industries. This heat can only be achieved within a short time several thousand degree heat, they can in a very short period of time to cut off the heat source

Photoelectric conversion: This method is the solar energy directly into electrical energy. Photoelectric conversion is the use of solar radiation is an important way, to date, this approach has just 40 years old. It is the use of certain substances in the photoelectric effect to the direct solar radiation into electrical energy, its core is the solar cell. At present, the major solar cell has silicon cells, CdS cells, GaAs cells and GaAs – AlGaAs battery.

Conversion efficiency, due to different materials, generally about 10%, only as a special small power supply. At present solar cells have been used in lighthouses, beacons, microwave relay stations, electric fences, railway signals, mobile phones, TV transmission, television receivers, no weather stations, cathodic protection of metal and electronic toys, calculators, electronic watches and so on. With the technology and reduce the price of materials, solar cells will power the application to the larger development.

Photochemical Conversion: green plants photosynthesis is a photochemical conversion process. Photosynthesis is the plant use sunlight to carbon dioxide and water into organic material.

Currently, many scientists are using this approach produce fuel. The approach is, in those who do not compete with food production in the barren hills, wasteland, wasteland and lake areas, planting green plants, green plants and then harvested to use chemical or biological means, and can be solid fuel, liquid fuel, fertilizer and petrochemical substitutes. For example, the Philippines, a large number of plant Leucaena trees (growing particularly fast), to provide firewood for the industry. Brazil’s use of its large-scale cultivation of sugar cane to the development of ethanol fuel industry. 1983 Brazil 1 / 4 by 280 motor fuel is ethanol plants provide.

2. Collector

Solar energy is more dispersed, to try to put it together to use. All use of solar energy collector is a key part of the device.

What is a collector do? Collector is to absorb solar radiation to the working fluid (water) heat transfer device. It is the water heater’s “heart.” Because the collector of the working fluid (water) and long-distance exchange of the Sun, so it is a heat exchanger.

We know that the sun is composed of different wavelengths, different materials and different colors on different wavelengths of light absorption and reflection capability is not the same. Black color of the strongest ability to absorb sunlight, so wear a coat in winter most of the people is made of dark or black clothing. The strongest reflection of white sunlight, so the summer shirt fabrics are produced using light-colored or white. Study in the use of solar energy, so that parallel light through the focusing lens gathered in one point, a line or a small area on the collector can achieve the purpose. We all know that paper in the sun, no matter how strong the sun, even during the hot summer sun will not be lit. However, if the use of concentrator, the light gathered in the paper, soon, the focus of Department will burn the paper. Based on these life and scientific practice, under the guidance of the theory, the scientists created a variety of collectors, their characteristics, are generally divided into the following.

1. Flat-plate collector: Cover the vegetable greenhouse on the transparent plastic film is such a case, heating room, a few fans that belong to a large glass window plate solar collector. It will not only collect the sun’s direct radiation, and scattering the sun’s radiation can be collected. Flat solar collector is based on “hot box principle” design. The so-called hot-box, is the side facing the sun and the transparent cover, use glass, fiberglass or plastic film to cover the other three sides ProBook 4210s battery of blackened walls and the gas-tight insulation. When the sunlight through the glass into the box, so that the inner wall coating is absorbed into heat energy. If the box filled with water, the water is heated.

2. Vacuum tube solar collectors: flat plate solar collector is based on the developed device. Vacuum insulation, and selective absorbing coating to improve the collector efficiency and collector temperature of the new solar collector device. Constitute the core components of this collector is the vacuum tube ‘which mainly absorbs heat within the body and the outer layer of the glass composition.

By heat-absorbing body of material is different from vacuum tube solar collectors can be divided into all-glass vacuum tube solar collector and a metal glass vacuum tube solar collector into two categories.

All-glass vacuum tube solar collectors of simple structure, and the convenience, reliability, low cost, has many outstanding advantages, it is elongated like a thermos bottle, glass tube formed by the two concentric circles, drawn into the vacuum between the inside and outside the tube, solar selective absorbing coating (surface film) deposition, including the outer surface of tube body composition absorbs heat, the solar energy is converted to heat energy, heating the heat transfer fluid within the tube. Glass, a metal tube is all glass vacuum tube, following the international developed a new generation of vacuum tubes after. As the heat-absorbing body of metal material, and vacuum tubes are used between the metal pieces to connect, so, the composition of these vacuum tube collector with high temperature, pressure capacity, and good thermal shock resistance.