For a long time, people have been trying to study and use solar energy. The solar energy received by our earth only accounts for about one billion of the total energy emitted by the sun's surface, which is equivalent to 30,000-40,000 times of the total energy needed by the world, which can be described as inexhaustible. Secondly, there is no distinction between day and night and four seasons, and there are no dark clouds and shadows, so the radiation energy is very stable. Therefore, the power generation system is relatively simple on the ground, and the strength requirements for equipment components are not too high in the cosmic environment of weightlessness and high vacuum. Moreover, unlike fossil fuels such as oil and coal, solar energy will not cause "greenhouse effect" and global climate change, nor will it cause environmental pollution. Because of this, the utilization of solar energy has attracted the attention of many countries, and everyone is competing to develop various new photoelectric technologies and materials to expand the application fields of solar energy utilization. Especially in the past 10 years, we are increasingly looking forward to the arrival of the "solar energy era" under the attack of two major crises: the bottom of recoverable oil and the deterioration of ecological environment. From power generation, heating, water supply to various solar power generation devices, its application is very extensive, and in some fields, the utilization of solar energy has begun to enter the practical stage.
From 1974 to 1997, the power generation cost of silicon semiconductor photovoltaic cells in developed countries such as the United States and Japan decreased by an order of magnitude: from $50 to $5 per watt. Since then, most experts in the world believe that there is still a long way to go before solar power plants can compete with traditional power plants (mainly coal-fired power plants) economically-the cost can only be reduced by another order of magnitude. At present, the United States and other countries have established many projects using solar pools to generate electricity. On the shore of the Dead Sea, there is a 7000m2 experimental solar pond built in 1979, which provides heat for a150kW generator. The United States plans to build 8.3% of its salt lake area (about 8,000 square kilometers) into a solar pond to provide heat for a 600 MW generator set. In June this year, experts from Armenian Institute of Radio Physics announced that they had started to build its "first small-scale experimental model" industrial solar power station in the mountainous area of the country. The turbine used in this power station is not new, but was detached from the helicopter at the end of its service life. The installed capacity is only100KW, but the power generation cost is only 0.5 cents/kWh, and the efficiency is as high as 40%-50%.
Russian scholars have also made remarkable progress in the study of solar ponds. A company combines the solar water jet propeller and jet cooling propeller developed by it with the solar pond project, and designs a new type of solar pond suitable for farmers by attaching facilities such as ice tanks to the solar pond. According to this design, a farmer with 6 to 8 people can build a 70-square-meter solar pool, which can meet the annual electricity demand of his 100-square-meter house. Another institute put forward the design idea of combined solar pool power station, that is, using heat pump, heat pipe and other technologies to comprehensively utilize solar energy, geothermal energy and indoor waste heat, so that the cost of solar pool power generation is greatly reduced, which can be comparable to that of thermal power stations in the North Caucasus, and can be used all year round, air conditioning in summer and heating in winter.
For countries lacking fresh water resources, the solar pond has another rare benefit: according to experts' calculation, a solar pond with an area of 2 163 square kilometers and a depth of 1.2 meters will be built in the offshore shallow water area, which can supply heat for 10 GW generating 2 cubic kilometers of fresh water every year.
In some advanced countries in Europe and America, "photoelectric glass curtain wall product" is being widely used, which is a new type of ecological building material that seals solar energy conversion silicon wafer in double-layer tempered glass (especially laminated glass) and safely converts solar energy into electric energy. The "Photovoltaic Building Plan" in the United States, the "Million Roof Photovoltaic Plan" in Europe, the "Asahi Plan" in Japan and the "Bright Project" that has been carried out in China will set off an upsurge in the development and application of energy-saving and environmental-friendly ecological building materials in the building field, which will greatly promote the application of solar energy in new building materials products.
In developing countries, countries are also actively developing and utilizing solar energy. For example, in the Philippines, as early as 1999, the government approved the first solar energy project, and with the assistance of the Australian government's overseas aid program, 1000 solar energy systems were installed in 263 communities across the country. At present, the Philippine government is implementing the world's largest solar energy application plan, costing 48 million US dollars, which is by far the largest solar energy plan in the world. The solar power generation plan is divided into two phases, which not only benefits residential buildings, but also benefits 25 irrigation systems, 97 water purification and distribution systems, 68 schools and community centers and 35 clinics.
From this point of view, the solar energy era that all human beings dream of is actually close at hand, including collecting solar energy in space, transmitting it to the earth, transforming it into electric energy, and solving the energy crisis facing mankind. With the progress of science and technology, this is no longer a dream. The world's first solar power station, built by NASA and the Department of Energy, will be assembled in space in the near future and will soon start supplying power to the ground.
In China, the utilization of solar energy has always been the hottest topic. After years of development, domestic solar collectors (including solar water heaters) have become one of the most widely used and industrialized industries. 1998 has a total sales of 3.5 billion yuan, ranking first in the world in output. China's solar energy industry has started to operate. The Chinese Academy of Sciences announced the launch of the West Action Plan, and will invest 250 million yuan in research within two years to establish a number of demonstration projects such as solar power generation, solar energy heating and solar air conditioning. At present, Baoding National High-tech Development Zone is accelerating the construction of the largest polysilicon solar cell production base in China. The project integrates solar cells, components and application systems. After the completion of the first phase project, the annual output of 3 MW polysilicon solar cells can be reached, which fills many gaps in the development and application of solar energy in China and will greatly promote the production and sales market of low-iron glass for solar cells. On the whole, however, the domestic solar photovoltaic power generation system started late, especially in the research and development and production of solar cells, which is still in the primary stage with small output, narrow application, single product and backward technology. According to rough statistics, there are only five (monocrystalline silicon) solar cell factories in China, with an annual output of about 4.5 MW (note: 1 MW is 1000 kW), and the factory facilities are still on the imported production line. Many foreign companies have turned their attention to the development and production of more advanced thin-film crystalline solar cells. The conversion efficiency of this new generation of advanced thin film crystal solar cells can reach 18.3%, which is 3 percentage points higher than the current average conversion efficiency. According to industry insiders, the average conversion efficiency of solar cells in China is not high, mainly because of the low degree of localization of special materials, such as packaging glass completely dependent on imports. The market of high transmittance substrate glass with low iron content still can't meet the demand, and the scientific research achievements can't be quickly and completely transformed into industrial advantages.
At present, the State Planning Commission and the State Science and Technology Commission have given strong support to the development of solar energy technology and its application, and many domestic enterprises have also set foot in it. Beixin Group is one of the first organizations to organize experts to investigate the solar photovoltaic power generation industry at home and abroad. 1998 took the lead in introducing the international advanced 76 kW rooftop solar power generation system in China, which has been running stably and achieved good results. The average daily power generation of the system is more than 12 kwh, which can meet the electricity demand of 1 well-off families. The Group also established Beijing Atlan Solar Energy Technology Co., Ltd. with Swiss ATLANTIS Company as a joint venture to jointly produce two series and multiple varieties of photovoltaic power generation products, and introduced this world-leading new solar energy utilization technology into China.
Hebei Zhenhai Aluminum Group Co., Ltd. is the exclusive distributor of Pikington Solar International Co., Ltd. in China, and has put into production the world-advanced glass packaging equipment and supporting materials for solar cells, such as the high-quality wet glass laminating equipment and wet grouting liquid (packaging medium) of Kemmett Chemical Products Co., Ltd. Zhenhai Group's June base 1999 1 1 has been installed first 100 square meters.
Solar collector tube is a patented technology in Tsinghua University, which is industrialized by Tsinghua Sunshine Company. At present, the annual output ranks first in the world, and the product performance leads the world. It took Tsinghua Sunshine Company six or seven years to complete the small-scale, pilot-scale and large-scale production of solar collector tubes and collectors. At present, the world's largest solar collector tube factory has been built, which can produce 5 million all-glass vacuum collector tubes with the highest thermal efficiency in the world every year. It is expected that the business volume of this project will be very fast.