WELCOME TO DEPARTMENTAL SEMINAR on S OLAR TOWER TECHNOLOGY

INTRODUCTION RENEWABLE ENERGY is from an energy resource that is replaced rapidly by a natural process such as power generated from the sun or from the wind.

Sources of Renewable energy

Solar Mission SOLARMISSION aims to be one of the world’s leading producers of clean, green renewable energy within five years. Solar Mission is committed to providing profitable, large- scale renewable energy generation power stations for the United States and the world’s electricity markets. Our objective is to lead the renewable energy market with innovative technologies that do not consume fuel sources or produce green house gas emissions. that is, with no detrimental effects on the environment from large-scale electricity production. The Solar Tower project will change the world’s energy markets forever, and possibly, reduce the effects of global warming.

History of Solar Tower One of the earliest description of solar chimney power station was written in 1931 by German author Hans Günter. More recently Schalaic,Bergerman and Partner,under the direction of German engineer Prof. Dr.Jorg Schalaic,built a small scale working model of a solar chimney in 1982 in Manzanares(Spain),which was funded by German Government. This power plant operated successfully for approx. 8 years and was decommissioned in 1989.The chimney had a diameter of 10 meters and height of 195 mt,with a collection area of 46,000 m 2 obtaining a maximum power output of 50kw. During operation,optimisation data was collected on a second-by-second basis.This data has been licensed to Enviromission and SolarMission Technologies who planned to develop the concept under the brand name “Solar Tower”

Solar Tower Technology Solar tower is not simply solar energy. Solar Tower technology is created when the sun’s radiation is used to heat a large body of air,which is then forced by the laws of physics(hot air rises) to move as a hot wind through large turbines to generate electricity. A solar thermal power station using solar tower technology will create the conditions to cause hot wind to flow continuously through its turbines to generate electricity.

Components of solar thermal power station Solar thermal power station is composed of three major components: 1. the solar collector 2. solar tower 3. solar turbines

COLLECTOR : Solar collectors are the key component of active solar-heating systems. Solar collector gather the sun’s energy,transfom its radiation into heat,then transfer that heat to water,solar fluid,or air. There are several types of solar collector : 1. Flat plate collectors 2. Evacuated-tube collectors 3. Concentrating collectors 4. Transpired Air collectors

FLAT PLATE COLLECTOR : Flat plate collector system comprises an insulated, weatherproof box containing a dark absorber plate under one or more transparent or translucent covers. As the fluid flows through the pipes it is heated. Flat plate collector is of 2 types 1. Liquid Flat Plate Collector 2. Air Flat Plate Collector

WATER FLAT PLATE COLLECTOR

AIR FLAT PLATE COLLECTOR

EVACUATED TUBE COLLECTOR : The collector consists of rows of parallel transparent glass tubes, each of which contains an absorber covered with selective coating. In the evacuated tube collector,sunlight enters through the outer glass tube and strikes the absorber,where the energy is convertd to heat.The heat is transferred to the liquid flowing through the absorber. Air is evacuated from the space between the two tubes, forming a vaccum. This reduces conductive and convective heat loss from the interior of the tube.

EVACUATED-TUBE COLLECTOR

CONCENTRATING COLLECTOR : Concentrating collectors use curved mirrors to concentrate sunlight on the receiver. It uses a focusing device, an absorber/receiver provided with or without transparent cover and a tracking device for continuously following the sun. There are 4 basic types of concentrating collectors 1. Parabolic trough collectors 2. Parabolic dish system 3. Power Tower System 4. Stationary concentrating collectors

PARABOLIC TROUGH SYSTEM Parabolic troughs are devices that are shaped like the letter “u”.The troughs concentrate sunlight onto a receiver tube that is positioned along the focal line of the trough. Parabolic troughs often use single-axis or dual- axis tracking.

PARABOLIC DISH SYSTEM A parabolic dish collector is similar in appearance to a large satellite dish, but has mirror-like reflectors and an absorber at the focal point.It uses a dual axis sun tracker. This system uses a computer to track the sun and concentrate the sun’s rays onto a receiver located at the focal point in front of the dish.

POWER TOWER SYSTEM A heliostat uses a field of dual axis sun trackers that directs solar energy to a large absorber located on a tower. The power tower has a field of large mirrors that follow the sun’s path across the sky. The mirrors concentrate sunlight onto a receiver on top of a tower.A computer keeps the mirror aligned so the reflected rays of sun are always aimed at the receiver.High pressure steam is generated to produce electricity

STATIONARY CONCENTRATING SOLAR COLLECTORS Stationary concentrating collectors use compound parabolic reflectors and flat reflectors for directing solar energy to an absorber through a wide acceptance angle. The wide acceptance angle for these reflectors eliminates the need for a sun tracker.

TRANSPIRED AIR COLLECTORS: Transpired air collectors are made of dark,perforated metal. The sun heats the metal, and a fan pulls ambient air through the holes in the metal, which heats the air. They have been used for preheating ventilation air and for crop drying. These collectors require no glazing or insulation. Thats why these are inexpensive to manufacture.

TURBINE : There are 32 turbines used in solar tower which is the only moving parts. With the use of turbines,mechanical output in the form of rotational energy can be derived from the moving air in the tower. Turbines are constructed from light weight alloy materials.

Factors determined the power station site Solar radiation levels Weather patterns Geological stability Acess to the electricity grid Geographic features Current land use Environmental factors Federal government support State government support Local government/regional support

Location of Site The first 200 MW SolarTower is planned to commence construction in Australia in 2006, at Burronga Station, in the Riverland area of New South Wales.The project will be handled by publicly listed company EnviroMission Limited.

Specifications & capacity Tower 3000 feet high, 400 feet Diameter Concrete 750,000 cubic yards Collector 3.5 miles diameter (30 million square yards) glass/polycarbonate/plastic film Turbines 32 units x 6.25 Megawatt Land square miles (4.5 x 4.5) Construction 34 months Jobs (Construction), 15 (ongoing) Output 200 Megawatts (200,000 households)

Future Prospects Australian government recently approved this project, called “solar mission”. As per its 200Mwatt capacity its set up cost of 800m$ will be recovered in nearly 23 years. Spain,German and Israel Govt are also considering this project for its clean energy

Feasibility in our country Indian government decision only to import coal makes the thermal power a lot more expensive. For the present boom in our economy the government has to solve the power with long term investments. The Thar desert in Rajastan has to be utilized with such projects.

Artist’s rendition

THANK YOU SUDHANSU NAYAK REGD.NO TH-SEMESTER BRANCH-MECHANICAL