Information about solar energy

Solar energy comes from celestial bodies (mainly solar energy) outside the earth. Most of the energy needed by human beings comes directly or indirectly from the sun. It is all kinds of plants that convert solar energy into chemical energy through photosynthesis and store it in plants. Fossil fuels such as coal, oil and natural gas are also formed by ancient plants and animals buried underground after a long geological age. They are essentially the fixed solar energy of ancient creatures. In addition, water energy, wind energy, wave energy and ocean current energy are also converted from solar energy. The energy contained in the earth itself usually refers to the energy related to the internal heat energy of the earth and the energy related to the nuclear reaction. The energy related to nuclear reaction is nuclear energy. When the structure of the nucleus changes, it can release a lot of energy, which is called nuclear energy, or atomic energy for short. It comes from nuclear fission energy such as uranium and plutonium stored in the crust when fission occurs, and nuclear fusion energy such as deuterium, tritium and lithium stored in the ocean when fusion occurs. When a nuclear reaction occurs, these substances release energy. At present, the biggest use of nuclear energy is power generation. In addition, it can also be used as other types of power and heat sources. Tidal energy in the world can be converted into about 3 billion tons of coal every year, but actually only the shallow sea area can be used, which can be converted into about 60 million tons of coal every year. The basic ways of solar energy utilization can be divided into the following four categories. Solar energy is a huge energy released by the fusion of hydrogen nuclei at ultra-high temperature. Solar energy is a treasure house of human energy, such as fossil energy, wind energy on the earth and biomass energy all come from the sun. Utilization of solar energy Indirect utilization of solar energy: Direct utilization of fossil energy (light energy-chemical energy) and biomass energy (light energy-chemical energy) Solar energy collectors (including flat-plate collectors and concentrating collectors) (light energy-internal energy) Solar cells: (light energy-electric energy) are generally used in satellites and spacecraft.

Edit the technical principle of this paragraph.

At present, the use of solar energy is not very popular, and there are still problems of high cost and low conversion efficiency in using solar energy to generate electricity, but solar cells have been used to provide energy for artificial satellites. Solar energy is the energy generated by the nuclear fusion reaction of sunspots inside or on the surface of the sun. Earth Orbit Zhuhai Solar Energy hot water engineering

The average solar radiation intensity in orbit is 1369w/㎡. The circumference of the equator of the earth is 40000km, and it can be calculated that the energy obtained by the earth can reach173,000 tw. The standard peak intensity of sea level is 1kw/m2, and the 24-hour annual average radiation intensity at a certain point on the earth's surface is 0.20 kW/m2, which is equivalent to the energy of 102000TW. Human beings depend on these energy sources for survival, including all other forms of renewable energy (except geothermal energy). Although the total amount of solar energy resources is equivalent to more than 1 10,000 times of the energy currently used by human beings, the energy density of solar energy. These characteristics of solar energy will limit its role in the whole integrated energy system. Although the energy radiated by the sun to the earth's atmosphere is only 2.2 billion times of its total radiation energy, it is as high as 173000 tw, which means that the energy radiated by the sun to the earth every second is equivalent to 5 million tons of coal. Wind energy, water energy, ocean temperature difference energy, wave energy, biomass energy and some tidal energy on the earth all come from the sun; Even the fossil fuels on the earth (such as coal, oil, natural gas, etc. ) are basically solar energy stored since ancient times, so the broad sense of solar energy covers a very large range, while the narrow sense of solar energy is limited to the direct conversion of solar radiation into photothermal, photoelectric and photochemical energy. Solar energy is both primary energy and renewable energy. It is rich in resources, can be used for free, does not need transportation, and has no pollution to the environment. It has created a new life form for human beings, and brought society and human beings into an era of energy saving and emission reduction.

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Solar photovoltaic

Photovoltaic panel module is a kind of power generation device that generates direct current under sunlight, and it is composed of thin solid photovoltaic cells made almost entirely of semiconductor materials (such as silicon). Because there are no moving parts, it can run for a long time without any loss. Simple photovoltaic cells can provide energy for watches and computers, while more complex photovoltaic systems can provide lighting for houses and power for power grids. Solar energy utilization of photovoltaic panels

Components can be made into different shapes, and connecting components can generate more electricity. In recent years, photovoltaic panels have been used on roofs and building surfaces, and even as a part of windows, skylights or shielding devices. These photovoltaic facilities are usually called photovoltaic systems attached to buildings.

solar thermal power

Modern solar thermal energy technology gathers sunlight and uses its energy to generate hot water, steam and electricity. In addition to using appropriate technology to collect solar energy, buildings can also use the light and heat of the sun by adding appropriate equipment in the design, such as giant south-facing windows or building materials that can absorb and slowly release solar heat.

Advantages and disadvantages of editing this paragraph

superiority

(1) Universality: the sun shines all over the earth, and there is no geographical restriction. Both land and sea, mountains and islands can be directly developed and utilized without mining and transportation. (2) Harmless: the development and utilization of solar energy will not pollute the environment, and it is one of the cleanest energy sources, which is extremely valuable in today's increasingly serious environmental pollution. (3) Huge: The solar radiation energy reaching the earth's surface every year is equivalent to about 65.438+0.3 trillion tons of coal, which is the largest energy that can be developed in the world today. (4) Long-term: According to the current speed of nuclear energy generated by the sun, the storage of hydrogen is enough to last for several billion years, and the life of the earth is about several billion years. In this sense, it can be said that the energy of the sun is inexhaustible.

disadvantaged

(1) dispersion: Although the total amount of solar radiation reaching the earth's surface is large, the energy flow density is very low. On average, near the Tropic of Cancer, when the weather is clear in summer, the irradiance of solar radiation is the highest at noon. In the area perpendicular to the direction of sunlight, the average solar energy received is about 1 000 w; If the average day and night of the whole year is only about 200W W, only about half in winter and only about 1/5 on cloudy days, the energy flow density is very low. Therefore, when using solar energy, in order to get a certain conversion power, a set of collection and conversion equipment with a considerable area is often needed, and the cost is high. (2) Instability: Due to the limitation of natural conditions such as day and night, season, geographical latitude and altitude, and the influence of random factors such as sunny, cloudy, cloud and rain, the solar irradiance reaching a certain ground is intermittent and extremely unstable, which increases the difficulty of large-scale application of solar energy. In order to make solar energy a sustainable and stable energy source and eventually become an alternative energy source that can compete with conventional energy sources, it is necessary to solve the problem of energy storage, that is, to store the solar radiation energy in sunny days as much as possible for use at night or in rainy days, but at present, energy storage is also one of the weak links in solar energy utilization. (3) Low efficiency and high cost: The current development level of solar energy utilization is feasible in theory and mature in technology. However, some solar energy utilization devices cannot compete with conventional energy sources economically because of their low efficiency and high cost. In the future, the further development of solar energy utilization is mainly restricted by economy. [1] The "black spring" in 2065438+00 has become a permanent pain in the hearts of some solar water heater enterprises. In the eyes of many enterprises, the decline of the industry is a foregone conclusion. According to Xu, secretary general of Jiaxing Solar Energy Association, "At present, there are 360 vacuum tube hotlines in Haining, Jiaxing, with an annual output of 8 million solar water heaters. Since the beginning of this year, there has been a serious overcapacity, a backlog of products, half-stop and half-work, and even a tragic situation in which machines are sold as scrap iron. " ?

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Photothermal utilization

Its basic idea is to collect solar radiation energy and convert it into heat energy through interaction with matter for utilization. At present, there are three kinds of solar collectors that are used most, namely flat plate collectors, vacuum tube collectors and focusing collectors. Generally speaking, solar photothermal utilization can be divided into low-temperature utilization (< 200℃), medium-temperature utilization (200-800℃) and high-temperature utilization (> 800℃) according to the different temperatures and uses. At present, the low-temperature utilization mainly includes solar water heaters, solar dryers, solar distillers and solar energy.

[2] Solar house, solar greenhouse, solar air conditioner and refrigeration system, etc. , mainly including solar cookers, solar thermal power concentrating and heat collecting devices, etc. And a high-temperature solar furnace.

Solar power generation

The large-scale utilization of solar energy in the future will be used for power generation. There are many ways to use solar energy to generate electricity. At present, there are two kinds of practical ones. ① Optical-thermal-electrical conversion. That is, using the heat energy generated by solar radiation to generate electricity. Generally, solar collectors are used to convert the absorbed heat energy into working medium steam, and then the steam drives the gas turbine to drive the generator to generate electricity. The former process is photothermal conversion, and the latter process is thermoelectric conversion. ② photoelectric conversion. Its basic principle is to directly convert solar radiation energy into electric energy through photovoltaic effect, and its basic device is solar cell.

Photochemical utilization

This is a photochemical conversion method that uses solar radiation energy to directly decompose water to produce hydrogen.

Photobiological utilization

The process of converting solar energy into biomass is realized by photosynthesis of plants. At present, there are mainly fast-growing plants (such as firewood forests), oil crops and giant algae.

Edit the development history of this paragraph.

According to records, human beings have used solar energy for more than 3000 years. The use of solar energy as an energy source and power has only a history of more than 300 years. It is a recent thing to really regard solar energy as "the supplementary energy urgently needed in the near future" and "the foundation of future energy structure". Since 1970s, solar energy technology has advanced by leaps and bounds, and solar energy utilization has changed with each passing day. The history of modern solar energy utilization can be counted from 16 15 when French engineer Solomon de Cox invented the world's first solar engine. The invention is a machine that uses solar energy to heat air to expand it to do work and pump water. During the period of 16 15 ~ 1900, many solar power generation devices and some other solar devices were developed in the world. Almost all of these power plants collect sunlight by concentrating light, and the engine power is not large. The working medium is mainly water vapor, which is expensive and of little practical value. Most of them are developed and manufactured by solar enthusiasts themselves. During the 20th century 100, the development history of solar energy technology can be roughly divided into seven stages.

The first stage (1900~ 1920)

At present, the focus of solar energy research in the world is still solar power station, but the light gathering methods are diversified, using flat plate collectors and low boiling point working fluids. The factory building is gradually expanding, and the maximum output power reaches 73.64kW. The practical purpose is clear and the cost is still high. Typical installation is as follows: 190 1 year, California, USA, built a solar water pumping device with a truncated cone condenser with a power of 7.36kW；; From 1902 to 1908, five sets of dual-cycle solar engines were built in the United States, using flat-plate collectors and low-boiling working fluids; 19 13 years, a solar water pump consisting of five parabolic trough mirrors was built in the south of Cairo, Egypt, each with a length of 62.5m and a width of 4m, with a total lighting area of 1250m2.

The second stage (1920~ 1945)

In the past 20 years, solar energy research has been at a low tide, and the number of people involved in research and research projects has greatly decreased. The reason is related to the extensive development and utilization of fossil fuels and the occurrence of World War II (1935~ 1945), and solar energy can't solve the urgent demand for energy at that time, so solar energy research is gradually ignored.

The third stage (1945~ 1965)

In the 20 years after World War II, some farsighted people noticed that oil and natural gas resources were rapidly decreasing, and called on people to pay attention to this problem, so as to gradually promote the recovery and development of solar energy research, establish solar energy academic organizations, hold academic exchanges and exhibitions, and revive the upsurge of solar energy research. At this stage, some significant progress has been made in solar energy research. It is worth noting that: 1945, Bell Laboratories developed a practical silicon solar cell, which laid the foundation for the large-scale application of photovoltaic power generation; 1955, Taber of Israel put forward the basic theory of selective coating at the first international conference on solar thermal science, and developed practical selective coatings such as black nickel, which created conditions for the development of efficient collectors. In addition, there are other important achievements at this stage, notably: 1952, the French National Research Center built a 50kW solar furnace in the east of the Pyrenees. 1960, the world's first ammonia absorption air conditioning system with flat plate collector was built in Florida, USA, with a cooling capacity of 5 cold tons. 196 1 year, schematic diagram of solar energy utilization.

Stirling engine with time window came out. At this stage, the research on the basic theory and materials of solar energy has been strengthened, and major breakthroughs have been made in technologies such as solar selective coating and silicon solar cells. The flat plate collector has made great progress and the technology is gradually mature. The research of solar absorption air conditioning has made progress, and a number of experimental solar houses have been built. The stirling engine and tower solar thermal power generation technology, which are difficult, are studied preliminarily

The fourth stage (1965~ 1973)

At present, the research of solar energy is stagnant, mainly because the technology of solar energy utilization is in the growth stage, immature, and the investment is large, and the effect is not ideal, so it is difficult to compete with conventional energy sources, so it has not received the attention and support of the public, enterprises and the government.

The fifth stage (1973~ 1980)

Since oil has occupied a dominant position in the world energy structure, it has become a key factor affecting the economy and determining the survival, development and decline of a country. When the Middle East War broke out in June 5438+0973, the Organization of Petroleum Exporting Countries took measures such as reducing production and raising prices to support the struggle of the people in the Middle East and safeguard their own interests. As a result, those countries that rely on importing cheap oil from the Middle East have suffered a heavy economic blow. As a result, some people in the west exclaimed that there was an "energy crisis" in the world (some people called it an "oil crisis"). This "crisis" objectively makes people realize that we must completely change the existing energy structure and accelerate the transition to the future energy structure. Therefore, many countries, especially industrialized countries, have renewed their support for the development of solar energy and other renewable energy technologies, and the upsurge of developing and utilizing solar energy has once again arisen in the world. From 65438 to 0973, the United States made a government-level solar power generation plan, and the funds for solar energy research increased substantially, and a solar energy development bank was established to promote the commercialization of solar energy products. 1974, Japan announced the "sunshine plan" formulated by the government, in which solar research and development projects include: solar houses, industrial solar systems, solar thermal power generation, solar cell production systems, decentralized and large-scale photovoltaic power generation systems, etc. In order to implement this plan, the Japanese government has invested a lot of manpower, material resources and financial resources. In the early 1970s, the upsurge of solar energy development and utilization in the world also had a great impact on China. Some far-sighted scientific and technological personnel have devoted themselves to the solar energy industry, actively made suggestions to relevant government departments, published books and magazines, and introduced the international solar energy utilization trends; Popularize the application of solar cookers in rural areas, develop solar water heaters in cities, and begin to use solar cells in space on the ground. 1975, "the first national solar energy utilization experience exchange conference" was held in Anyang, Henan province, which further promoted the development of solar energy in China. After this meeting, the research and promotion of solar energy was included in the plan of our government and received special funds and material support. Some universities and research institutes have successively set up solar energy research groups and laboratories, and some places have also begun to set up solar energy research institutes. At that time, there was an upsurge in the development and utilization of solar energy in China. During this period, the development and utilization of solar energy is in an unprecedented period of great development, which has the following characteristics: countries have strengthened the planning of solar energy research, and many countries have formulated short-term and long-term sunshine plans. The development and utilization of solar energy has become a government act, and the support has been greatly strengthened. International cooperation is very active, and some third world countries have begun to actively participate in the development and utilization of solar energy. The research field has been continuously expanded and the research work has been deepened, and a number of important achievements have been made, such as CPC, vacuum collector tubes, amorphous silicon solar cells, hydrogen production by photolysis of water, solar thermal power generation and so on. The solar energy development plans formulated by various countries generally have the problems of demanding too much and being too urgent, and the difficulties in the implementation process are underestimated. It is hoped to replace mineral energy in a short time and realize the large-scale utilization of solar energy. For example, the United States had planned to build a small solar demonstration satellite power station in 1985 and a 5 million kilowatt space solar power station in 1995. In fact, this plan was later adjusted, and the space solar power station has not yet been launched. Solar water heaters, solar cells and other products began to be commercialized, and the solar energy industry was initially established, but the scale was small and the economic benefits were not ideal.

The sixth stage (1980~ 1992)

The upsurge of solar energy development and utilization, which arose in 1970s, began to ebb shortly after 1980s, and gradually entered a trough. Many countries in the world have cut the funds for solar energy research, among which the United States is the most prominent. The main reasons for this phenomenon are: the world oil price has fallen sharply, while the price of solar products remains high and lacks competitiveness; There is no major breakthrough in solar energy technology, and the goal of improving efficiency and reducing costs has not been achieved, which has shaken the confidence of some people in developing and utilizing solar energy; The rapid development of nuclear energy has restrained the development of solar energy. Influenced by the international low solar energy in 1980s, the research work of solar energy in China has also been weakened. Some people even suggested that solar energy is the future energy source, with large investment, poor effect, difficult energy storage and wide land occupation, and advocated that China should introduce technology after successful research abroad. Although a few people hold this view, it is very harmful and has a negative impact on the development of solar energy in China. At this stage, although the funds for solar energy development and research have been greatly reduced, the research work has not been interrupted, and some projects have made great progress, which urges people to carefully examine the previous plans and objectives, adjust the focus of research work, and strive to achieve greater results with less investment.

The seventh stage (1992 ~ present)

Due to the massive burning of mineral energy, it has caused global environmental pollution and ecological destruction, posing a threat to human survival and development. Against this background, the United Nations held the World Conference on Environment and Development in Brazil in 1992, which adopted a series of important documents, such as Rio de Janeiro Declaration on Environment and Development, 2/kloc-0 Agenda for the Century, and the United Nations Framework Convention on Climate Change, which brought environment and development into a unified framework and established a model of sustainable development. After this meeting, countries all over the world strengthened the development of clean energy technology, and combined the utilization of solar energy with environmental protection, so that the utilization of solar energy went out of the trough and was gradually strengthened. After the World Conference on Environment and Development, the government of China attached great importance to the environment and development, and put forward 10 countermeasures, specifically to "develop and popularize clean energy such as solar energy, wind energy, geothermal energy, tidal energy and biomass energy according to local conditions", and formulated "China 2 1 Century Agenda", which further clarified the key development projects of solar energy. 1995 The State Planning Commission, the State Science and Technology Commission, and the State Economic and Trade Commission formulated the Outline for the Development of New and Renewable Energy, which was formulated in (1996 ~ 20 10) and clearly put forward 196 ~ 20 10. The formulation and implementation of these documents have played an important role in further promoting the development of China's solar energy industry. 1996, the United Nations held the World Solar Summit in Zimbabwe. After the meeting, the Harare Declaration on Solar Energy and Sustainable Development was issued. Important documents such as 10 (1996 ~ 2005) World Solar Action Plan, International Solar Congress and World Solar Strategic Plan were discussed. This meeting further demonstrated the firm determination of the United Nations and other countries in the world to develop solar energy, and called on the whole world to act together to make extensive use of solar energy. After 1992, the world's solar energy utilization has entered a development period, which is characterized by: solar energy utilization is closely integrated with the world's sustainable development and environmental protection, and the world is making joint efforts to realize the world's solar energy development strategy; The development goal of solar energy is clear, the key points are prominent, and the measures are effective, which is conducive to overcoming the disadvantages of cold and hot and overheating in the past and ensuring the long-term development of solar energy; While increasing the research and development of solar energy, we should pay attention to the transformation of scientific and technological achievements into productive forces and develop solar sewage plants.

Develop solar energy industry, speed up the commercialization process, expand the field and scale of solar energy utilization, and gradually improve economic benefits; International cooperation in the field of solar energy is unprecedentedly active, with expanded scale and obvious effects. From the above review, we can see that the development path of solar energy is not smooth in the 100 year of this century. Generally, there will be a low tide after every high tide, and the low tide time is about 45 years. The development process of solar energy utilization is completely different from that of coal, oil and nuclear energy, and people have different understandings of it, which is repeated many times and takes a long time to develop. On the one hand, it shows that the development and large-scale utilization of solar energy is difficult in a short time; On the other hand, it also shows that the utilization of solar energy is also affected by mineral energy supply, politics and war, and the development road is tortuous. Nevertheless, on the whole, the progress of solar technology in the 20th century is still faster than any previous century. [3]

Stage 8 (Future)

When photovoltaic panels all over the world are connected to the power grid, the problem of difficult energy storage will be improved. First, economic development is a problem. More and more countries in the world realize that a sustainable society should meet the needs of society without endangering the future of future generations. Therefore, replacing fossil energy with clean energy as much as possible is the principle that energy construction should follow. With the change of energy form, the storage of conventional energy is decreasing day by day, and its price is bound to rise, so it is necessary to increase investment to control environmental pollution. Second, China is the largest producer and consumer of coal in the world. Coal accounts for about 76% of the consumption structure of commodity energy and has become the main source of air pollution in China. Vigorously developing the utilization technology of new energy and renewable energy will become an important measure to reduce environmental pollution. The energy problem is worldwide, and the period of transition to new energy will come sooner or later. In the long run, the wide application of solar energy utilization technology and devices will inevitably restrict the rise of mineral energy prices.

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