太阳能
太阳能(Solar)一般指太阳光的辐射能量。在太阳内部进行的由“氢”聚变成“氦”的原子核反应,不停地释放出巨大的能量,并不断向宇宙空间辐射能量,这种能量就是太阳能。太阳内部的这种核聚变反应,可以维持几十亿至上百亿年的时间。太阳向宇宙空间发射的辐射功率为3.8x10^23kW的辐射值,其中20亿分之一到达地球大气层。到达地球大气层的太阳能,30%被大气层反射,23%被大气层吸收,其余的到达地球表面,其功率为800000亿kW,也就是说太阳每秒钟照射到地球上的能量就相当于燃烧500万吨煤释放的热量。平均在大气外每平米面积每分钟接受的能量大约1367w。广义上的太阳能是地球上许多能量的来源,如风能,化学能,水的势能等等。狭义的太阳能则限于太阳辐射能的光热、光电和光化学的直接转换。
人类对太阳能的利用有着悠久的历史。我国早在两千多年前的战国时期,就知道利用钢制四面镜聚焦太阳光来点火;利用太阳能来干燥农副产品。发展到现代,太阳能的利用已日益广泛,它包括太阳能的光热利用,太阳能的光电利用和太阳能的光化学利用等。太阳能的利用有光化学反应,被动式利用(光热转换)和光电转换两种方式。太阳能发电一种新兴的可再生能源利用方式。
使用太阳电池,通过光电转换把太阳光中包含的能量转化为电能,使用太阳能热水器,利用太阳光的热量加热水,并利用热水发电,利用太阳能进行海水淡化。现在,太阳能的利用还不很普及,利用太阳能发电还存在成本高、转换效率低的问题,但是太阳电池在为人造卫星提供能源方面得到了应用。
主要是硅光电池在吸收太阳所发射出来的光能,硅光电池主要是从沙子里提炼出来的,由贝尔实验室开发。太阳能是太阳内部或者表面的黑子连续不断的核聚变反应过程产生的能量。地球轨道上的平均太阳辐射强度为1367w/㎡。地球赤道的周长为40000km,从而可计算出,地球获得的能量可达173000TW。在海平面上的标准峰值强度为1kw/m2,地球表面某一点24h的年平均辐射强度为0.20kw/㎡,相当于有102000TW 的能量,人类依赖这些能量维持生存,其中包括所有其他形式的可再生能源(地热能资源除外),虽然太阳能资源总量相当于现在人类所利用的能源的一万多倍,但太阳能的能量密度低,而且它因地而异,因时而变,这是开发利用太阳能面临的主要问题。太阳能的这些特点会使它在整个综合能源体系中的作用受到一定的限制。
尽管太阳辐射到地球大气层的能量仅为其总辐射能量的22亿分之一,但已高达173,000TW,也就是说太阳每秒钟照射到地球上的能量就相当于500万吨煤。地球上的风能、水能、海洋温差能、波浪能和生物质能以及部分潮汐能都是来源于太阳;即使是地球上的化石燃料(如煤、石油、天然气等)从根本上说也是远古以来贮存下来的太阳能,所以广义的太阳能所包括的范围非常大,狭义的太阳能则限于太阳辐射能的光热、光电和光化学的直接转换。
太阳能既是一次能源,又是可再生能源。它资源丰富,既可免费使用,又无需运输,对环境无任何污染。为人类创造了一种新的生活形态,使社会及人类进入一个节约能源减少污染的时代。
太阳电池是一对光有响应并能将光能转换成电力的器件。能产生光伏效应的材料有许多种,如:单晶硅,多晶硅,非晶硅,砷化镓,硒铟铜等。它们的发电原理基本相同,现以晶体为例描述光发电过程。P型晶体硅经过掺杂磷可得N型硅,形成P-N结。
当光线照射太阳电池表面时,一部分光子被硅材料吸收;光子的能量传递给了硅原子,使电子发生了跃迁,成为自由电子在P-N结两侧集聚形成了电位差,当外部接通电路时,在该电压的作用下,将会有电流流过外部电路产生一定的输出功率。这个过程的的实质是:光子能量转换成电能的过程。
“硅”是我们这个星球上储藏最丰量的材料之一。自从19世纪科学家们发现了晶体硅的半导体特性后,它几乎改变了一切,甚至人类的思维,20世纪末.我们的生活中处处可见“硅”的身影和作用,晶体硅太阳电池是近15年来形成产业化最快。生产过程大致可分为五个步骤:a、提纯过程 b、拉棒过程 c、切片过程 d、制电池过程 e、封装过程。
太阳能光伏
光伏板组件是一种暴露在阳光下便会产生直流电的发电装置,由几乎全部以半导体物料(例如硅)制成的薄身固体光伏电池组成。由于没有活动的部分,故可以长时间操作而不会导致任何损耗。简单的光伏电池可为手表及计算机提供能源,较复杂的光伏系统可为房屋提供照明,并为电网供电。 光伏板组件可以制成不同形状,而组件又可连接,以产生更多电力。近年,天台及建筑物表面均会使用光伏板组件,甚至被用作窗户、天窗或遮蔽装置的一部分,这些光伏设施通常被称为附设于建筑物的光伏系统。
太阳热能
现代的太阳热能科技将阳光聚合,并运用其能量产生热水、蒸气和电力。除了运用适当的科技来收集太阳能外,建筑物亦可利用太阳的光和热能,方法是在设计时加入合适的装备,例如巨型的向南窗户或使用能吸收及慢慢释放太阳热力的建筑材料。
据记载,人类利用太阳能已有3000多年的历史。将太阳能作为一种能源和动力加以利用,只有300多年的历史。真正将太阳能作为“近期急需的补充能源”,“未来能源结构的基础”,则是近来的事。20世纪70年代以来,太阳能科技突飞猛进,太阳能利用日新月异。近代太阳能利用历史可以从1615年法国工程师所罗门·德·考克斯在世界上发明第一台太阳能驱动的发动机算起。该发明是一台利用太阳能加热空气使其膨胀做功而抽水的机器。在1615年~1900年之间,世界上又研制成多台太阳能动力装置和一些其它太阳能装置。这些动力装置几乎全部采用聚光方式采集阳光,发动机功率不大,工质主要是水蒸汽,价格昂贵,实用价值不大,大部分为太阳能爱好者个人研究制造。20世纪的100年间,太阳能科技发展历史大体可分为七个阶段。
第一阶段(1900~1920年)
在这一阶段,世界上太阳能研究的重点仍是太阳能动力装置,但采用的聚光方式多样化,且开始采用平板集热器和低沸点工质,装置逐渐扩大,最大输出功率达73.64kW,实用目的比较明确,造价仍然很高。建造的典型装置有:1901年,在美国加州建成一台太阳能抽水装置,采用截头圆锥聚光器,功率:7.36kW;1902 ~1908年,在美国建造了五套双循环太阳能发动机,采用平板集热器和低沸点工质;1913年,在埃及开罗以南建成一台由5个抛物槽镜组成的太阳能水泵,每个长62.5m,宽4m,总采光面积达1250m2。
第二阶段(1920~1945年)
在这20多年中,太阳能研究工作处于低潮,参加研究工作的人数和研究项目大为减少,其原因与矿物燃料的大量开发利用和发生第二次世界大战(1935~1945年)有关,而太阳能又不能解决当时对能源的急需,因此使太阳能研究工作逐渐受到冷落。
第三阶段(1945~1965年)
在第二次世界大战结束后的20年中,一些有远见的人士已经注意到石油和天然气资源正在迅速减少, 呼吁人们重视这一问题,从而逐渐推动了太阳能研究工作的恢复和开展,并且成立太阳能学术组织,举办学术交流和展览会,再次兴起太阳能研究热潮。 在这一阶段,太阳能研究工作取得一些重大进展,比较突出的有:1945年,美国贝尔实验室研制成实用型硅太阳电池,为光伏发电大规模应用奠定了基础;1955年,以色列泰伯等在第一次国际太阳热科学会议上提出选择性涂层的基础理论,并研制成实用的黑镍等选择性涂层,为高效集热器的发展创造了条件。此外,在这一阶段里还有其它一些重要成果,比较突出的有: 1952年,法国国家研究中心在比利牛斯山东部建成一座功率为50kW的太阳炉。1960年,在美国佛罗里达建成世界上第一套用平板集热器供热的氨——水吸收式空调系统,制冷能力为5冷吨。1961年,一台带有石英窗的斯特林发动机问世。在这一阶段里,加强了太阳能基础理论和基础材料的研究,取得了如太阳选择性涂层和硅太阳电池等技术上的重大突破。平板集热器有了很大的发展,技术上逐渐成熟。太阳能吸收式空调的研究取得进展,建成一批实验性太阳房。对难度较大的斯特林发动机和塔式太阳能热发电技术进行了初步研究。
Solar
Solar (Solar) generally refers to the sun's radiation energy. Carried out in the solar interior from "H" together into a "helium" the nuclear reaction, kept a huge release of energy, and continue to the space radiation energy, which is solar energy. This solar nuclear fusion reaction inside the can to maintain the hundreds of millions of百亿年first time. Solar radiation to space launch 3.8x10 ^ 23kW power of the radiation, of which 20 billionth of the Earth's atmosphere to reach. Solar energy reaching the Earth's atmosphere, 30% of the atmosphere reflectance, 23% of atmospheric absorption, and the rest to reach the Earth's surface,
Its power of 80 trillion kW, that is to say a second exposure to the sun's energy on Earth is equivalent to five million tons of coal combustion heat release. The average per square meter in the atmosphere outside the area of energy per minute to receive about 1367w. A broad sense of the solar energy on earth many sources, such as wind energy, chemical energy, potential energy of water and so on. The narrow sense is limited to solar radiation of solar light thermal, photovoltaic and photochemical conversion of the directly.
At this stage, the world's solar energy is still the focus of the study of solar energy power plant, but the diversification of the use of the condenser, and the introduction of flat-plate collector and a low boiling point working fluid, the device gradually expanded up to maximum output power 73.64kW, Objective To compare the clear and practical, cost remains high. The construction of a typical device are as follows: 1901, California built a solar-powered pumping devices, the use of truncated cone condenser power: 7.36kW; 1902 ~ 1908 years, built in the United States five sets of double-cycle solar-powered engines, the use of flat-panel collector and a low boiling point working fluid; in 1913,
Human use of solar energy has a long history. China more than 2000 years ago, back in the Warring States period, one will find that the use of four steel mirror to focus sunlight ignition; use of solar energy to dry agricultural products. The development of modern, solar energy has become increasingly widespread use, it includes the use of solar energy solar thermal, solar photovoltaic and solar energy use, such as the photochemical use. The use of solar photochemical reaction, a passive use (photo-thermal conversion) and the photoelectric conversion in two ways. A new solar power and renewable sources of energy use.
Silicon photovoltaic cells mainly in the absorption of solar light energy emitted by silicon photocell is mainly extracted from the sand by the development of Bell Labs. Solar energy is the internal or the surface of the sun sunspot continuous process of nuclear fusion reactions produce energy. Earth's orbit on the average solar radiation intensity for the 1367w / ㎡. Circumference of the Earth's equator to 40000km, and thus calculated the Earth's energy can be obtained 173000TW. At sea level standard for peak intensity 1kw/m2, a point on the Earth's surface 24h of the annual average radiation intensity 0.20kw / ㎡, which is equivalent to have 102000TW energy
Human dependence on these energy to survive, including all other forms of renewable energy (except for geothermal energy resources), although the total amount of solar energy resources is the human equivalent of the energy used by ten thousand times, but low energy density of solar energy, and it vary from place to place, from time to time change, the development and utilization of solar energy which is facing a major problem. These features will make solar energy in the integrated energy system of the role of subject to certain restrictions.
The use of solar cells, through the photoelectric conversion to solar energy conversion is included in electricity, the use of solar water heaters, the use of solar heat hot water and use water for power generation, using solar energy for desalination. Now, the use of solar energy is not very popular, the use of solar power costs are high there, the problem of low conversion efficiency, but for satellite solar cells to provide energy has been applied.
Although the Earth's atmosphere solar radiation to the total energy only 22 billionths of a radiation energy, it has been as high as 173,000 TW, that is to say a second exposure to the sun's energy on Earth is equivalent to five million tons of coal. Earth wind energy, hydropower, ocean thermal energy, wave energy and tidal energy as well as some comes from the sun; even in the face of the earth's fossil fuels (such as coal, oil, natural gas, etc.) that is fundamentally Since ancient times the storage of solar energy down, so by including a broad range of solar energy is very large,
The narrow sense is limited to solar radiation of solar light thermal, photovoltaic and photochemical conversion of the directly.
Solar energy is the first time, but also renewable energy. It is rich in resources, can use free of charge, and without transportation, without any pollution to the environment. For mankind to create a new life, so that social and human energy into a era of reducing pollution.
Solar cells have to respond to a light and convert solar energy to power the device. Photovoltaic effect can produce many kinds of materials, such as: single crystal silicon, polycrystalline silicon, amorphous silicon, gallium arsenide, copper indium selenium. They are basically the same principle of power generation is now crystal as an example to describe the process of light generation. P-type crystalline silicon available after phosphorus-doped N-type silicon, the formation of P-N junction.
When the surface of solar light, the silicon material to be part of photon absorption; photon energy transfer to the silicon atom, electronic transitions have taken place, as a free-electron concentration in the PN junction formed on both sides of the potential difference, when the external circuit connected when the effects of the voltage, there will be a current flowing through the external circuit have a certain amount of output power. The substance of this process are: photon energy into electrical energy conversion process.
"Si" is our planet's abundance of storage materials. Since the 19th century, scientists discovered the properties of crystalline silicon semiconductor, it almost changed everything, even human thought, end of the 20th century. Our lives can be seen everywhere, "silicon" figure and role of crystalline silicon solar cells is the formation of the past 15 years the fastest growing industry. Production process can be divided into five steps: a, purification process b, the process of pulling rod c, slicing the process of d, the process of system battery e, the course package.
Solar photovoltaic
Is a component of photovoltaic panels in the sun exposure will generate direct current power generation devices, from virtually all semiconductor materials (eg silicon) are made of thin photovoltaic cells composed of solid. Because there is no part of activity, and would thus be a long time operation would not lead to any loss. Simple photovoltaic cells for watches and computers to provide energy, and more complex PV systems to provide lighting for the housing and power supply. Photovoltaic panels can be made into components of different shapes, and components can be connected to generate more power. In recent years, the surface of the roof and building will be the use of photovoltaic panels components,
Even be used as windows, skylights or sheltered part of devices, which are often called photovoltaic facilities with PV systems in buildings.
Solar thermal
Modern technology solar thermal polymerization sunlight and use its energy produced hot water, steam and electricity. In addition to the use of appropriate technology to collect solar energy, the building can also make use of the sun's light and heat energy is added in the design of appropriate equipment, such as large windows or use of the south can absorb and slowly release the sun heat the building materials .
According to records, human use of solar energy has more than 3,000 years of history. To solar energy as an energy and power use, only 300 years of history. The real solar as "the near future to add much-needed energy," "the basis of the future energy mix" is the latest thing. Since the 20th century, 70s, solar technology has made rapid advances, solar energy use with each passing day. Solar energy utilization in modern history from the French engineers in 1615 in the Solomon and Germany Cox invented the world's first solar-powered engines run. The invention is a use of solar energy heating the air to the expansion and pumping machines acting.
In 1615 ~ 1900, between the developed world and more than one solar power plant and a number of other solar energy devices. Almost all of these power plants collect the sun means the use of condenser, engine power is not, the working fluid is water vapor, which is very expensive, not practical value, the majority of individual studies for manufacturing solar enthusiasts. 100 years of the 20th century, the history of the development of solar energy technology in general can be divided into seven stages.
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