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Non-Conventional Energy Sources Solar energy (Working of Solar Chimney)

By Ch.Ambika(06761A0201) & Md.Shaheda Parvin(06761A0238)

e-mail anub4 u2 0 0 4 _ 1 8 @yahoo. co. in(9 9 8 5 8 8 3 7 0 3 )

DEPARTMENT OF ELECTRICAL AND ELECTRONIC ENGINEERING LAKIREDDY BALIREDDY COLLEGE MYLAVARAM

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Abstract : "The extraction, conversion, and utilization of energy is the single largest component of air and water pollution, as well as emissions causing the change of our global climate." The fossil fuels are being steadily depleted, and they cannot be replaced on any time scale of human civilizations. While the lifetime of oil and gas may exist through the first half of this century .So a quest for sustainable alternative must happen well before the physical or economic depletion. This lead to the utilization of non-conventional energy sources which are eco-friendly.

# This paper deals with solar energy, its production , its advantages over conventional energy sources , applications: Working of solar chimney ‘s(existing, latest and the future project.) Solar energy is not an “alternative energy”. It is the original and continuing primary energy source. This is non-polluting, inexhaustible, operates in stable harmony with the Earth’s physical and ecological systems, create jobs and new industries out of expenditures that previously had gone to purchase fuels , contribute to physical and economic self-sufficiency of nations ,and are available to both developed and developing nations, and cannot be used to make weapons i.e, its always an positive approach….

Solar energy is converted into electrical energy by means of a turbine. Heat from the sun is used to heat air and hence to run a turbine. This concept leads to the unbelievable invention named ‘The solar chimney’.

Introduction : Non-conventional energy resources are defined as those resources which cannot be depleted at any point of time and henceforth are called the renewables.

DocumentToPDF trial version, to remove this mark, please register this software. Various forms of non –conventional energy are Ø

Biomass energy and biogas energy

Ø

Geothermal energy

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Ocean thermal energy

Ø

Solar energy

Ø Wind energy

The concept: Energy from the sun travels to the earth in the form of electromagnetic radiation similar to radio waves, but in a different frequency range. The amount of energy available from the sun outside the Earth’s atmosphere is approximately 1367 W/m2; that’s nearly the same as a high power hair drier for every square meter of sunlight! Some of the solar energy is absorbed as it passes through the Earth’s atmosphere. As a result, on a clear day the amount of solar energy available at the Earth’s surface in the direction of the sun is typically 1000 W/m2 i.e, 46% of the entire energy.We roamed round the galaxy in search of such an energy, the result of which has led us here. Yes, the same old resource, the solar energy.

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Solar Energy Advantages Over Conventional Energy Sources: #

The energy from the sun is virtually free after the initial cost has been recovered.

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Solar and other renewable energy systems do not require any connection to a power or natural gas grid.

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The sun provides a virtually unlimited supply of solar energy.

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The use of solar energy results in a proportional decrease in green house gas

DocumentToPDF trial version, to remove this mark, please register this software. emissions. # The use of solar energy is a ever-lasting market. #

Every process involving production of power has carbon dioxide as an unavoidable waste product . But here there is no combustion and no carbon.

Disadvantages: # The disadvantage is initial high capital investment. # On cloudy days it will not be possible to generate solar energy. # Efficiency is only 20% while that in conventional is 60%-70%.

The solar chimney: Solar energy is converted into electrical energy by means of a turbine. Heat from the sun is used to heat air and hence to run a turbine. This concept leads to the unbelievable invention named ‘The solar chimney’. The figure next shows the picture of a solar chimney set up in Manzanares, Spain, in 1982.The idea was originally given by German structural engineer Schlaich Bergerman. The solar chimney power plant – converts global irradiance into electricity. Since chimneys are often associated negatively with exhaust gases, THIS CONCEPT IS ALSO KNOWN AS THE SOLAR TOWER POWER PLANT although it is totally different from the tower concepts. A solar chimney power plant has a high chimney (tower), with a height of up to 100 meters, and this is surrounded by a large collector roof, up to 3 miles in diameter, that consists of glass or resistive plastic supported on a framework which generates 15W of energy…

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Towards its center, the roof curves upward to join the chimney, creating a funnel. It is a massive arrangement and hence can be setup in places where large areas are available. This massive structure has no name resemblance with the chimneys in our kitchens or in local industries. We are dealing with something beyond the present imagination.

Mystery behind its working: The solar tower works like a giant inverted funnel, with a large gently sloping transparent outer section feeding into a steep chimney-like neck in the center. Greenhouse effects heat the air underneath, pushing it faster and faster toward the chimney where turbines converted the air flow to electricity. Due to a large base coverage area of several square kilometers, the air flow built up over that area concentrating in the one place -- the chimney -- would produce some pretty powerful wind flows -- enough to run a number of major cities. Thermodynamic modelling has predicted that a 200MW plant is feasible in engineering terms. Recent discussions have centered around heat storage using water tubes, permitting energy generation for several hours after sunset.

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The basic concept is that when air is heated, it tends to go up in the atmosphere since its specific volume increases. The sun heats up the ground (usually black surface) and the air underneath the collector roof, and the heated air follows the upward incline of the roof until it reaches the chimney. There, it flows at high speed through the chimney and drives wind generators at its bottom.

The ground under the collector roof behaves as a storage medium, and can even heat up the air for a significant time after sunset. This unique chimney is also helpful for green house effect. The large area under the double glazed cover can be utilized for vegetation purpose on basis of green house effect. Thus the area is not wasted and as well as, the energy, derived. Thus, finally after knowing all the information regarding the chimney it is found that the efficiency of the solar chimney power plant is below 2%-3% only and depends mainly on the height of the tower.

Where does the other 97% go? There is a temperature drop with altitude of about 10°C for a 100-meter chimney. Large quantities of warm air have to be lifted from the ground to chimney top. This is gravitational energy loss. The air that leaves the chimney is above ambient temperature at that altitude. This is thermal energy loss. Ambient air that is drawn into the collector is warmed and expands with little increase in pressure. The

DocumentToPDF trial version, to remove this mark, please register this software. majority of solar input is lost in the simple expansion of air before it reaches the turbine. None of this is surrendered to the turbine.

How to improve the rest of the efficiency? Would a regenerator improve efficiency? A modified solar chimney is proposed where the paramount consideration is the rigorous elimination of all energy losses. The solar collector is sealed and double-glazed with low emissivity glass. The entire floor area has a solar absorber. The chimney is well insulated and incorporates a heat exchanger along most of its length. Warm air rises from the solar collector and drives the turbine. Its residual energy is then transferred to incoming air in the heat exchanger - such energy recovery can be over 95% efficient. Incoming air enters well up the chimney at a level ‘h’ from the top, which is needed to drive the system. The incoming air is warmed as it travels down the chimney. It passes through the turbine and then between the two layers of glass to ground level, entering the solar collector from underneath the absorber.

NOW WE SHALL SEE THE LATEST AND FUTURE PROJECTS……

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LATES T PROJ ECT ENVIRO MISSION’S ……… # HEIGHT – 1000MTS(3281FT) # POWER GENERATED-200MW

FUTURE PROJ ECT THE NEW SOLAR POWER PLANT FOR NORTH-WEST VICTORIA IS EXPECTED TO BE THE BIGGEST IN WORLD (NASA’S IMAGE)

A COMPARISION TO SHOW HOW TALL IS THE SOLAR TOWER……

Ú Cheops pyramid – 449ft

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Sydney tower – 1014ft Eiffel tower- 1063ft Empire state building – 1473ft Solar tower – 3281ft(1000mts) We also conclude that power generated is directly proportional to the height of the tower.

Use in India: A tropical country like India can potentially generate 200MW power and this can be of great importance when utilized properly.

Conclusion: Really a boon to the growing world. Let us ‘invest’ on the chimney and enjoy the everlasting ‘interest’ with actually no ‘capital’. Hence we conclude that solar energy is one of the eco-friendly energy resource that

cannot be

depleted and is one of the best substitute for fuels from hydrocarbons that was prevailing till recent years. We hope that this paper will create an awareness of the depleting energy resources and bring out the necessity of usage of solar energy through the developing technologies like solar chimney’s or tower’s.

References: (1) www.ecotopia.com (2)www.wikipedia.com

Bibiliography:

(1)”Renewable energy sources”-John Twindell and Joney Weir. (2)”Non-conventional energy sources”-G.D.Rai.

T h is mail als o inc lud e s a animat ion wh ic h d e als wit h t h e f unc t ioning of t h e s olar c h imne y……