The sudden emergence of solar power generation is currently taking place. China's thermal power generation is the main cause, and thermal power generation has a huge negative impact on the ecological environment. With the deteriorating ecological environment, disposable energy such as coal and natural gas is increasingly depleted. Solar power is green and pollution-free. , Renewable and other characteristics, become a hot spot for new energy.
According to Shen Wenzhong, director of the Institute of Solar Energy Research at Shanghai Jiaotong University, China is one of the countries with abundant reserves of solar energy resources. The area with more than 2,000 hours of sunshine per year accounts for more than two-thirds of the country's total area, including conditional development. The desert and Gobi area of ​​the solar power station is about 300,000 square kilometers, which accounts for 23% of the total desert area in China. Solar power has great potential for development in China.
In April 2011, the successful results of the 50 MW trough solar project in Inner Mongolia were announced. Datang New Energy Co., Ltd. won the bid at the lowest price of 0.9399 yuan/kWh. Relevant data show that the total investment of the thermal power generation project in Inner Mongolia is about 1.6 billion yuan, and can generate more than 120 million kilowatt-hours per year. Ma Shenghong, a researcher at the Institute of Electrical Engineering of the Chinese Academy of Sciences, believes that this is China's first concession project for solar thermal power concessions. This tender is a "zero breakthrough" and is of great significance to China's development of solar thermal power plants.
The principle of solar thermal power generation is that sunlight is collected by a reflector into a solar energy collecting device, solar energy is used to heat the heat transfer medium (liquid or gas) in the collecting device, and then heated to form steam to drive or directly drive the generator to generate electricity. CSP has three types of systems: trough, tower and dish.
Among them, the trough technology has been commercialized on a large scale in foreign countries, the technology is relatively mature, but the power generation process requires a lot of water; tower technology and trough technology is quite, also need to use a lot of water; only disc technology only needs 1.4 Ascending water, it can adapt to desert and Gobi regions with long sunshine hours, and has the highest conversion rate in three kinds of CSP technologies.
Hu Xuehao, deputy chief engineer of the China Academy of Power Science and Technology Academy, believes that solar thermal power generation is the same as thermal power through steam turbines, and solar thermal power generation with thermal storage systems is more conducive to the stability and regulation of the power system. At present, the cost of solar thermal power generation is the same as the cost of photovoltaic power generation, but there is no thermal storage equipment for photovoltaic power generation, and solar thermal power generation can use thermal storage devices to provide stable power output. If thermal storage is considered, the integrated price of CSP is cheaper than PV.
The solar thermal power generation technology is increasingly mature Solar thermal power generation has become a hot spot for the development of renewable energy in the world. As early as the 1980s, more than 20 different types of solar thermal power stations with installed capacity of 500 kW or more have been built in foreign countries, of which the installed capacity of No. 1 and No. 2 of solar-powered solar thermal power plants in California, USA With 850 MW and 750 MW reached, solar thermal power generation has begun commercial operation.
China started relatively late. On June 1, 2007, the first 70-kilowatt solar tower solar thermal power generation system in China passed the appraisal and acceptance in Nanjing. On July 1, 2010, Asia's first tower solar thermal power station was built in Yanqing, Beijing.
With the country’s increasing emphasis on renewable energy, the development of the CSP industry is very rapid. According to Wang Zhifeng, special expert of the Energy Experts Committee, head of the National 973 Project Experts Group and director of the Key Laboratory of Solar Thermal Energy and Photovoltaic Systems of the Chinese Academy of Sciences, the Institute of Electrical Engineering, Institute of Engineering Thermophysics and other research institutes of the Chinese Academy of Sciences during the 10th Five-Year Plan period. And some solar energy companies have already started research projects on solar thermal power generation technology. At present, Chinese scientists have studied dish-type power generation systems, tower-type power generation systems, and trough-type light concentrating units. They have mastered a number of core technologies for solar thermal power generation, such as high-reflectivity high-precision mirrors and high-precision double-axis. Tracking control systems, heat transfer at high heat flux, solar thermoelectric conversion, etc.
“As far as CSP is concerned, it will take a long time for China to form a solar thermal power generation industry chain from basic materials, host equipment and system design integration.†Ma Shenghong told reporters that many cities in the western part of China are now preparing to launch a light For thermal power generation projects, the country has listed CSP as the first of the new energy incentives in the industry guidance catalogue, which is a significant benefit for the industrialization of CSP systems, and with the scale of production of related equipment, The cost of CSP will also drop rapidly during the 12th Five-Year Plan period.
In view of the future development of China's CSP industry, Ma Shenghong believes that although the CSP system is not high for domestic companies, the domestic companies are still in the hot oil cycle, energy storage and heat exchange technologies. To be further studied, the key is to learn more from Spain and Germany on the technology and experience of the large-scale system. In this regard, he suggested that mobilize the enthusiasm of the relevant units of the industry chain, through the actual training of the power plant projects to improve and strengthen the testing methods and experimental platforms of the industry chain. In addition, the government should strengthen quality control and establish a quality assessment system.
Photovoltaic power generation is expected to become the "leading energy" in the future
The strategic position of solar power in our country is becoming more and more important. In 2010, the "Decision on Accelerating the Cultivation and Development of Strategic Emerging Industries" promulgated by the State Council clearly stated that it would "explore a diversified solar photovoltaic solar thermal power generation market." The "Twelfth Five-Year Plan" outline just released this year also once again clarified the need to focus on the development of new energy industries including solar thermal utilization and photovoltaic solar thermal power generation.
The nuclear power plant accident caused by the Great Earthquake in Japan has caused governments and industry insiders to rethink new energy strategies. There are still many uncertainties in the issue of nuclear safety. While countries are considering plans to reduce nuclear power development, China has begun a comprehensive review of nuclear power plants under construction and suspended the approval of nuclear power projects.
Compared with wind power, the state's fine-tuning of the wind power industry policy has been implemented through the guidance of the industrial structure adjustment. In the future, wind turbines or parts manufacturing companies that do not meet the policy will not be encouraged by policies. Wind energy is a clean renewable energy source, but the wind is intermittent and the wind speed is not stable. Therefore, the amount of electricity generated by wind power generation is also unstable.
The solar thermal power generation is characterized by its good compatibility with the existing power grid, high photoelectric conversion rate, continuous and stable power generation and peaking power generation, and the production process of power generation equipment is green, environmentally friendly, and does not produce any toxic substances. attention. People in the industry generally believe that photovoltaic and solar thermal power generation all have good prospects. The two are not alternatives to each other, but parallel development. The 12th Five-Year Plan outlines that during the "12th Five-Year Plan" period. The state must focus on Tibet, Inner Mongolia, Gansu, Ningxia, Qinghai, Xinjiang, and Yunnan provinces to build more than 5 million kilowatts of solar power stations.
According to Huang Xiangzeng, chief scientist of the solar thermal power generation project and vice chairman of the China Electric Association, if China reaches 30,000 square kilometers of solar thermal power generation by 2020, it will be able to solve 30%-35% of the total electricity consumption in the country. The thermal power generation market can reach 22.5-30 trillion yuan. Based on this calculation, using the existing solar thermal power generation technology and annual conversion efficiency, the establishment of a power station in only about 100,000 square kilometers of sandy land in China can almost satisfy China's annual electricity consumption.
Relevant experts believe that under the general trend of global low-carbon economy and new energy, light-heating electrodes may become China's largest share of the dominant energy in the future.
According to Shen Wenzhong, director of the Institute of Solar Energy Research at Shanghai Jiaotong University, China is one of the countries with abundant reserves of solar energy resources. The area with more than 2,000 hours of sunshine per year accounts for more than two-thirds of the country's total area, including conditional development. The desert and Gobi area of ​​the solar power station is about 300,000 square kilometers, which accounts for 23% of the total desert area in China. Solar power has great potential for development in China.
In April 2011, the successful results of the 50 MW trough solar project in Inner Mongolia were announced. Datang New Energy Co., Ltd. won the bid at the lowest price of 0.9399 yuan/kWh. Relevant data show that the total investment of the thermal power generation project in Inner Mongolia is about 1.6 billion yuan, and can generate more than 120 million kilowatt-hours per year. Ma Shenghong, a researcher at the Institute of Electrical Engineering of the Chinese Academy of Sciences, believes that this is China's first concession project for solar thermal power concessions. This tender is a "zero breakthrough" and is of great significance to China's development of solar thermal power plants.
The principle of solar thermal power generation is that sunlight is collected by a reflector into a solar energy collecting device, solar energy is used to heat the heat transfer medium (liquid or gas) in the collecting device, and then heated to form steam to drive or directly drive the generator to generate electricity. CSP has three types of systems: trough, tower and dish.
Among them, the trough technology has been commercialized on a large scale in foreign countries, the technology is relatively mature, but the power generation process requires a lot of water; tower technology and trough technology is quite, also need to use a lot of water; only disc technology only needs 1.4 Ascending water, it can adapt to desert and Gobi regions with long sunshine hours, and has the highest conversion rate in three kinds of CSP technologies.
Hu Xuehao, deputy chief engineer of the China Academy of Power Science and Technology Academy, believes that solar thermal power generation is the same as thermal power through steam turbines, and solar thermal power generation with thermal storage systems is more conducive to the stability and regulation of the power system. At present, the cost of solar thermal power generation is the same as the cost of photovoltaic power generation, but there is no thermal storage equipment for photovoltaic power generation, and solar thermal power generation can use thermal storage devices to provide stable power output. If thermal storage is considered, the integrated price of CSP is cheaper than PV.
The solar thermal power generation technology is increasingly mature Solar thermal power generation has become a hot spot for the development of renewable energy in the world. As early as the 1980s, more than 20 different types of solar thermal power stations with installed capacity of 500 kW or more have been built in foreign countries, of which the installed capacity of No. 1 and No. 2 of solar-powered solar thermal power plants in California, USA With 850 MW and 750 MW reached, solar thermal power generation has begun commercial operation.
China started relatively late. On June 1, 2007, the first 70-kilowatt solar tower solar thermal power generation system in China passed the appraisal and acceptance in Nanjing. On July 1, 2010, Asia's first tower solar thermal power station was built in Yanqing, Beijing.
With the country’s increasing emphasis on renewable energy, the development of the CSP industry is very rapid. According to Wang Zhifeng, special expert of the Energy Experts Committee, head of the National 973 Project Experts Group and director of the Key Laboratory of Solar Thermal Energy and Photovoltaic Systems of the Chinese Academy of Sciences, the Institute of Electrical Engineering, Institute of Engineering Thermophysics and other research institutes of the Chinese Academy of Sciences during the 10th Five-Year Plan period. And some solar energy companies have already started research projects on solar thermal power generation technology. At present, Chinese scientists have studied dish-type power generation systems, tower-type power generation systems, and trough-type light concentrating units. They have mastered a number of core technologies for solar thermal power generation, such as high-reflectivity high-precision mirrors and high-precision double-axis. Tracking control systems, heat transfer at high heat flux, solar thermoelectric conversion, etc.
“As far as CSP is concerned, it will take a long time for China to form a solar thermal power generation industry chain from basic materials, host equipment and system design integration.†Ma Shenghong told reporters that many cities in the western part of China are now preparing to launch a light For thermal power generation projects, the country has listed CSP as the first of the new energy incentives in the industry guidance catalogue, which is a significant benefit for the industrialization of CSP systems, and with the scale of production of related equipment, The cost of CSP will also drop rapidly during the 12th Five-Year Plan period.
In view of the future development of China's CSP industry, Ma Shenghong believes that although the CSP system is not high for domestic companies, the domestic companies are still in the hot oil cycle, energy storage and heat exchange technologies. To be further studied, the key is to learn more from Spain and Germany on the technology and experience of the large-scale system. In this regard, he suggested that mobilize the enthusiasm of the relevant units of the industry chain, through the actual training of the power plant projects to improve and strengthen the testing methods and experimental platforms of the industry chain. In addition, the government should strengthen quality control and establish a quality assessment system.
Photovoltaic power generation is expected to become the "leading energy" in the future
The strategic position of solar power in our country is becoming more and more important. In 2010, the "Decision on Accelerating the Cultivation and Development of Strategic Emerging Industries" promulgated by the State Council clearly stated that it would "explore a diversified solar photovoltaic solar thermal power generation market." The "Twelfth Five-Year Plan" outline just released this year also once again clarified the need to focus on the development of new energy industries including solar thermal utilization and photovoltaic solar thermal power generation.
The nuclear power plant accident caused by the Great Earthquake in Japan has caused governments and industry insiders to rethink new energy strategies. There are still many uncertainties in the issue of nuclear safety. While countries are considering plans to reduce nuclear power development, China has begun a comprehensive review of nuclear power plants under construction and suspended the approval of nuclear power projects.
Compared with wind power, the state's fine-tuning of the wind power industry policy has been implemented through the guidance of the industrial structure adjustment. In the future, wind turbines or parts manufacturing companies that do not meet the policy will not be encouraged by policies. Wind energy is a clean renewable energy source, but the wind is intermittent and the wind speed is not stable. Therefore, the amount of electricity generated by wind power generation is also unstable.
The solar thermal power generation is characterized by its good compatibility with the existing power grid, high photoelectric conversion rate, continuous and stable power generation and peaking power generation, and the production process of power generation equipment is green, environmentally friendly, and does not produce any toxic substances. attention. People in the industry generally believe that photovoltaic and solar thermal power generation all have good prospects. The two are not alternatives to each other, but parallel development. The 12th Five-Year Plan outlines that during the "12th Five-Year Plan" period. The state must focus on Tibet, Inner Mongolia, Gansu, Ningxia, Qinghai, Xinjiang, and Yunnan provinces to build more than 5 million kilowatts of solar power stations.
According to Huang Xiangzeng, chief scientist of the solar thermal power generation project and vice chairman of the China Electric Association, if China reaches 30,000 square kilometers of solar thermal power generation by 2020, it will be able to solve 30%-35% of the total electricity consumption in the country. The thermal power generation market can reach 22.5-30 trillion yuan. Based on this calculation, using the existing solar thermal power generation technology and annual conversion efficiency, the establishment of a power station in only about 100,000 square kilometers of sandy land in China can almost satisfy China's annual electricity consumption.
Relevant experts believe that under the general trend of global low-carbon economy and new energy, light-heating electrodes may become China's largest share of the dominant energy in the future.
A Screw, or Bolt, is a type of fastener characterized by a helical ridge, known as an external thread , wrapped around a cylinder. Some screw threads are designed to mate with a complementary thread, known as an internal thread, often in the form of a Nut or an object that has the internal thread formed into it. Other screw threads are designed to cut a helical groove in a softer material as the screw is inserted. The most common uses of screws are to hold objects together and to position objects.
A screw will always have a head, which is a specially formed section on one end of the screw that allows it to be turned, or driven. Common tools for driving screws include screwdrivers and wrenches. The head is usually larger than the body of the screw, which keeps the screw from being driven deeper than the length of the screw and to provide a bearing surface. There are exceptions; for instance, carriage bolts have a domed head that is not designed to be driven; set screws have a head smaller than the outer diameter of the screw; J-bolts have a J-shaped head which is not designed to be driven, but rather is usually sunk into concrete allowing it to be used as an anchor bolt. The cylindrical portion of the screw from the underside of the head to the tip is known as the shank; it may be fully threaded or partially threaded.[1] The distance between each thread is called the "pitch".
The majority of screws are tightened by clockwise
rotation, which is termed a right-hand thread; a common mnemonic device
for remembering this when working with screws or bolts is
"righty-tighty, lefty-loosey." Screws with left-hand threads are used in
exceptional cases. For example, when the screw will be subject to
counterclockwise torque (which would work to undo a right-hand thread), a
left-hand-threaded screw would be an appropriate choice. The left side pedal of a bicycle has a left-hand thread.
Screw
Anchor Screw, Chipboard Screw, Machine Screw, Double Screw
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