Solar energy


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A detail account of Solar energy

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Solar energy

  3. 3. THE SUN Sun is a star. Sun is the centre of our solar system and all planets revolve around the sun. About 75% of the sun is made up of hydrogen and most of the rest is helium. As we wonder, sun is 5 billion years old. How the energy doesn’t get exhausted? It is because of nuclear fusion reaction taking place inside the sun Two hydrogen atoms fuses together to form a helium atom. This reaction releases tremendous amount of heat and light energy. H1+1H1= 2He4 1
  4. 4. Earlier view The energy released from the sun is the source for all planets , mainly for our earth, as it supports life. Therefore, Sun is the primary source of energy for our world. It provides energy to all living beings This energy is used by the plant to prepare food by photosynthesis and other creatures depend on it directly or indirectly This energy is also used for cooking food, drying clothes etc:, in earlier days.
  5. 5. Modern view But, sun today is not only used for preparing food. It is used as an ALTERNATIVE SOURCE OF ENERGY Solar energy is widely used all over the world as a source for generating power. This energy is a renewable resource and pollution free. It can be utilized in many ways Here we are going to discuss about the solar energy- what? Uses, How it can be used, advantages and disadvantages, applications etc:-
  6. 6. What is solar energy? Solar energy
  7. 7. How much solar energy? The surface receives about 47% of the total solar energy that reaches the Earth. Only this amount is usable.
  8. 8. Solar constant The amount of solar energy received by one square meter area of near earth space at an average distance between the sun and the earth, is called solar constant. Thus, solar constant tells us the amount of energy which falls in 1 second on a 1 square metre area of the near earth space at an average distance between the sun and the earth. The value of solar constant is 1.4kj/s/m2 (or) 1.4 kW/m2
  9. 9. SOLAR ENERGY- PRESENT SCENARIO As solar energy is abundant for our use we can use it for many purposes. Therefore capturing heat energy is easiest way to use solar energy It can be used to heating water, transport and reconnaissance, solar ventilation, water treatment , architecture and horticulture . Produce electricity through various ways The fossil fuels are non renewable sources so we can not depend on them forever. Though nuclear energy is a clean and green energy ,as said by Dr.A.P.J Abdul Kalam, there are always some problems associated with it. So the only option we have is solar energy because it is a nonpolluting and silent source of electricity and also low maintenance and long lasting energy.
  10. 10. PRESENT SCENARIO Sales Fossils Fossil s Bio-fuels Hydro-based Nuclear SOLAR(0.8%) Windmills
  11. 11. USES OF SOLAR ENERGY Heaters Cars Green houses water pumps Lights Desalination Satellites Chilling Dryers Solar ponds Commercial use On an office building , roof areas can be covered with solar panels . Remote buildings such as schools , communities can make use of solar energy. Even on the highways , for every five kilometres ,solar telephones are used. In developing countries , this solar panels are very much useful.
  12. 12. Putting Solar Energy to Use: Heating Water Two methods of heating water: passive (no moving parts) and active (pumps). In both, a flat-plate collector is used to absorb the sun’s energy to heat the water. The water circulates throughout the closed system due to convection currents. Tanks of hot water are used as storage.
  13. 13. Heating Water: Active System Active System uses antifreeze so that the liquid does not freeze if outside temp. drops below freezing.
  14. 14. Heating, cooling and ventilation Solar heating, cooling and ventilation can be used as offset a portion of this energy. A solar chimney is a passive solar ventilation system. As the chimney warms, the air inside is heated This causing an updraft that pulls air through the building.
  15. 15. Water treatment Solar distillation can be used to make saline. Solar water disinfection (SODIS) involves exposing water-filled plastic polyethylene terephthalate (PET) bottles to sunlight for several hours Solar energy may be used in a water stabilisation pond to treat waste water.
  16. 16. Transport and reconnaissance Development of a solar-powered car has been an engineering goal since the 1980s. Some vehicles use solar panels for auxiliary power, for air conditioning To keep the interior cool, for reduced fuel consumption A solar balloon is filled with ordinary air. As sunlight shines on the balloon, the air inside is heated and expands causing an upward buoyancy force.
  17. 17. Architecture and Horticulture Agriculture and horticulture optimises solar energy in order to optimise plant productivity Planting cycles, tailored row orientation, heights between rows and the mixing of plant varieties improves crop yields Greenhouses converts solar light to heat, enables yearround production and the growth
  18. 18. SOLAR COOKER The solar cooker is a device which is used to cook food by utilising the heat energy radiated by the sun. What is solar cooker made of ? A solar cooker consists of an insulated metal box or wooden box which is painted all black from inside. There is a thick glass sheet covering over the box and a plane mirror reflector is also attached to the box. The food to be cooked is put inside the solar cooker box and covered with the glass sheet.
  19. 19. WORKING OF SOLAR COOKER In order to cook food, the solar cooker is kept in sunshine. The reflector of solar cooker is adjusted in such a way that it faces the sun. When the sun’s rays fall on the the reflector, the reflector sends them to the top of solar cooker box in the form of a strong beam of sunlight. The sun’s heat rays pass through the glass sheet cover and get absorbed by the black inside surface of the cooker box. Once the heat rays absorbed, then the glass sheet doesn’t allow them to escape. In this way, more and more heat rays of sun get trapped in the box due to which the temperature rises upto 100 degree Celsius to 140 degree Celsius. This heat the food materials kept in the black containers.
  20. 20. SOLAR CELLS Solar cell is a device which converts solar energy into electrical energy. SOLAR CELL IS MADE OF: A solar cell is usually made from silicon. A simple solar cell consists of sandwich of a silicon- boron layer and a silicon- arsenic layer . The amount of boron and arsenic present in the two silicon layers is however very small. A small piece of wire is soldered at the top of upper layer of cell and another piece of wire is soldered at the bottom of the lower layer.. A solar cell is covered with a glass cover or transparent plastic cover protection.
  21. 21. WORKING OF SOLAR CELLS • When solar panels are placed in the sunlight , photons will strike the surface and emits electrons. • As a result electron hole pair is created in the solar cell. • When external circuit is connected to the solar cell , electrons flow in the circuit and the current is generated.  When sunlight falls on the surface of solar cell, it makes the loosely held electrons in the silicon atoms move due to which, a current begins to flow in the wires connected to top and bottom of the cell.
  22. 22. SOLAR PANELS Solar panel is a device which is collection of solar cells. Solar panel consists of a large number of solar cells joined together in a definite pattern. A solar panel can provide much more electric power than a single solar cell. The various solar cells in a solar cell panel are joined together by connecting wires made of silver metal. This is because silver is the best conductor of electricity. It increases the efficiency of solar cell panel. At many places, the solar panels are mounted on specially designed inclined roofs so that more solar energy is incident on them.
  23. 23. Use of solar panel- Water pump. The solar panel has hundreds of solar cells joined together. The solar panel receive solar energy and is converted into electricity. The electricity produced is stored in battery . This battery runs an electric motor . And this motor finally drives a pump which pumps out the underground water This can be used to irrigate fields in villages.
  24. 24. SOLAR SAIL Solar sail is a umbrella- like stretched surfaces around the satellites or the ISS. There are solar plants, which provide energy to the objects in the flight. It is a new technology, which uses the pressure of the solar radiation to drive the space probes. It has solar devices which capture energy from sun and uses it. The magnetic sail is a future based concept going to be developed which uses the solar wind, coming from the sun.
  25. 25. IS NUCLEAR ENERGY SAFE?  Today in present world, nuclear energy is considered as      important source of energy. Even in India , nuclear energy has been given importance. Recently, kudankulam project has also started functioning. For the present world, nuclear energy seems to be as a high yielding source for power and harm free too. But nuclear energy has devastating effects on people. Nuclear wastes produced during production cannot be disposed. Radiation contaminates always even there is nuclear accident- Around uranium mine, enrichment facility, nuclear plants and nuclear wastes.
  26. 26. Impact of radiations.  Nuclear power plants has radiation on plants animals and humans too.  Impacts on vegetation Trees near jadugha uranium mines have deformed seeds.  Impact on animals Radioactive boars on the rise in Germany.
  27. 27. Impact of radiation in Chernobyl till date
  28. 28. Impact on babies in Iraq after American bombing
  30. 30. WHY? IN INDIA?  Still nuclear power plants are pushed in India.  Why?  Profit for MNC’S who will provide reactors to nuclear power plants  Commisions for politicians, scientists and intellectuals
  31. 31. SOLAR REPLACES NUCLEAR.  Recent researches say that only 10% of electricity demand        can be fulfilled by nuclear energy. Electricity demand- 800,00,000 MW. NUCLEAR POWER- 60000 MW Why risk lives of humans for just 10% of electricity? If not nuclear, then comes renewable sources of energy. Wind energy, hydropower energy and SOLAR ENERGY. Out of this, solar energy has the capability to feed the earth 1000 times than it’s demand. The utilized solar energy can give more energy than needed.
  32. 32. SOLAR ENERGY VS NUCLEAR ENERGY. Solar energy Nuclear energy  Renewable source  Non- renewable of energy  Pollution and radiation free  Have no effects on life  Can feed more than the demanded  Radiation is more.  Have effects on every living thing  Feed less than the demanded power.
  33. 33. Advantages and Disadvantages Advantages • All chemical and radioactive polluting byproducts of the thermonuclear reactions remain behind on the sun, while only pure radiant energy reaches the Earth. • Energy reaching the earth is incredible. By one calculation, 30 days of sunshine striking the Earth have the energy equivalent of the total of all the planet’s fossil fuels, both used and unused! Disadvantages • Sun does not shine consistently. • Solar energy is a diffuse source. To harness it, we must concentrate it into an amount and form that we can use, such as heat and electricity. • Addressed by approaching the problem through: • 1) collection, 2) conversion, 3) storage.
  34. 34. ENERGY STORING METHODS Phase change materials such as paraffin wax and Glauber's salt are another thermal storage media. These materials are inexpensive, readily available, and can deliver domestically useful temperatures (approximately 64 °C). The "Dover House" (in Dover, Massachusetts) was the first to use a Glauber's salt heating system, in 1948. Solar energy can be stored at high temperatures using molten salts. Salts are an effective storage medium because they are low-cost, have a high specific heat capacity and can deliver heat at temperatures compatible with conventional power systems. The Solar Two used this method of energy storage, allowing it to store 1.44 TJ in its 68 m3 storage tank with an annual storage efficiency of about 99%.[ Off-grid PV systems have traditionally used rechargeable batteries to store excess electricity. With grid-tied systems, excess electricity can be sent to the transmission grid, while standard grid electricity can be used to meet shortfalls. Net metering programs give household systems a credit for any electricity they deliver to the grid
  35. 35. A REPORT FROM IEA The International Energy Agency has said that solar energy can make considerable contributions to solving some of the most urgent problems the world now faces: Participants in a workshop on sustainable development inspect solar panels at Monterrey Institute of Technology and Higher Education, Mexico City on top of a building on campus. The development of affordable, inexhaustible and clean solar energy technologies will have huge longer-term benefits. It will increase countries’ energy security through reliance on an indigenous, inexhaustible and mostly import-independent resource, enhance sustainability, reduce pollution, lower the costs of mitigating climate change, and keep fossil fuel prices lower than otherwise. These advantages are global. Hence the additional costs of the incentives for early deployment should be considered learning In 2011, the International Energy Agency said thatto be widely shared. investments; they must be wisely spent and need solar energy technologies such as photovoltaic panels, solar water heaters and power stations built with mirrors could provide a third of the world’s energy by 2060 if politicians commit to limiting climate change. The energy from the sun could play a key role in de-carbonizing the global economy alongside improvements in energy efficiency and imposing costs on greenhouse gas emitters. "The strength of solar is the incredible variety and flexibility of applications, from small scale to big scale". We have proved ... that after our stores of oil and coal are exhausted the human race can receive unlimited power from the rays of the sun. —Frank Shuman, New York Times, July 2, 1916
  36. 36. BETTER WAYS OF USAGE Government should take measures and see that solar lights are used as street lights in all the areas. We can place solar panels in the barren lands instead of keeping it away uselessly. We can also keep these solar panels in the deserts , where we can make use of this energy with the help of a rechargeable battery. Efficiency of solar panels depends on the range of frequencies of light that strikes the surface . So they can give higher efficiency if we split the light into different frequency ranges and direct the beams onto the cells tuned to these frequencies. Building a new home is the best time to design and orient the home to take the advantage of the sun’s rays.