Final

1. Introduction2. The Solar Chimney

a. Parts of the Solar Chimney i. Collectorii. Turbinesiii. Chimney

b. Working Principles of Solar Chimneyc. Technology

3. The Energy Storage In the Collector4. Cost5. The Mildura Solar Chimney

6. Advantages

7. Disadvantages

8. Conclusion

9. References

The end of oil is coming; The energy demand will be doubled in the next 30 years Insecurity in energy supplies International tensions However a major threat is more urgent to be encountered Climate ChangeThe overall electrification rate in India is 64.5% while 35.5% of the population still live without access to electricity.Total Installed Capacity in India (as on 30-06-2011) is 1,76,990.40 MW

Today, there is a growing awareness that some alternative energy sources could have an important role to play in the production of electricity.

However, only the solar energy represents totally nonpolluting inexhaustible energy resource

35,000 km² area of the Thar Desert has been set aside for solar power projects, sufficient to generate 700 to 2,100 GW. In 2010, total worldwide energy consumption was 1,32,000 TWh (377lack MW). The potential for renewable energy is:

solar energy 4,44,000 TWh, wind power 1,67,000 TWh, geothermal energy 1,39,000 TWh, biomass 70,000 TWh, Hydropower 14,000 TWh and ocean energy 280 TWh.

For India, because of location, solar energy is best suited.

Fig. 1 The Prototype Manzanares Solar Chimney.

There are lots of methods of using the solar energy , and the Solar Chimney is one of them, which can be seen below, in figure 1.

In 1978, it was suggested by Professor Schlaich of Stuttgart university that power could be produced by a hybrid solar system. The solar chimney system consists of three parts;

The collector, Turbines. The chimney.

2.a.i. The Collector

Collector is the part, which is used to produce hot air bygreen-house effect. It is usually 5-6 meters high and covers a very large area about thousands of m² as seen in fıgure 2.

Fig. 2 The Collector.

Fig. 3 The glazed collector roof of Solar Chimney.

There is no limitation for the surface area. The larger the area, the more energy generated from the chimney.

There should be slightly increasing height towards to the chimney in order to obtain minimum friction loss.

Covering materials may be different, such as; glass, plastic film or glazed collector. The most efficient one is glazed collector.

It can convert up to 70% of irratiated solar energy into heat a typical annual average is 50%.

2.a.ii. Turbines

Turbines, seen in figure 4, are used to convert air current to the mechanical energy. Turbines are placed horizontally in chimney, vertically in the collector. To do this, one big turbine or a few small turbines should be used in chimney, as can be seen from the figure 5. and figure 6.

Fig. 4 Turbine for Solar Chimney

Power Station.

Fig. 5 Turbine with large

diameter [5].

Fig. 6 Small turbines [5].

2.a.iii. The chimney

The most important part of the plant is the chimney,seen in fıgure 7.

It acts likes a pressure tube.

Fig. 7 The chimney.

Longer the chimneys height, the more the energy produced from the chimney. The efficiency of the chimney is not depend on the amount of the temperature rising, but depends on the outside temperature.

• Thus, efficiency directly proportional to the ratio between the height of the chimney and the outside temperature.

Transparent roof, which is seen in fıgure 8, admits the short wave solar radiation component and retains long-wave radiation from the heated ground.

Thus, when solar radiation pass through the transparent roof it is absorbed by the ground elements and it converts into heat energy.

Fig. 8 Transparent roof.

Fig 8 Working of power plant through air flow

So, Why use a pipe or air channel to enclose the turbines? Why not have a large "wind farm  ," with turbines mounted on towers in

the open air?

Answer:

First, the wind turbines enclosed in a pipe can produce

8 times as much power for a given wind speed than a turbine in the open air.

Second, the wind farm concept would require a much larger numbers of turbines.

Also, the wind speed in the open air around the collector is significantly less than the air velocity through the air channel.

The Floating Solar Chimney

is made by a set of successive

tubular balloons, can be

constructed with an existing

polyester fabric giving low

investment cost(as shown in

the figure beside). These tubes are lighter than

air due to internal lighter than

air gas (He or NH4)

This accordion type folding end is unfolding partly when the structure is bending, securing that the warm air does not escape from its bottom.

Direction of Wind

Main Chimney made of parts

Heavy Mobile Base

Folding Lower Part

Chimney Seat

Upper Ring of the heavy base

Strong fabric of the heavy base

Lower ring of the heavy base

Accordion type folding lower

part

Seat of the floating solar

chimney

Lifting TubeFilled with lifting

Gas

Supporting RingInflated or

Aluminum tube

Inner fabric wall

Upper Ring of the heavy base

Strong fabric of the heavy base

Lower ring of the heavy base

Accordion type folding lower

part

Seat of the floating solar

chimney

Lifting TubeFilled with lifting

Gas

Supporting RingInflated or

Aluminum tube

Inner fabric wall

The body with the heavy base of the Floating Solar Chimney is inclining due to external winds.

Wind direction

Due to the titling property of the FSC, its operational height is decreasing under external winds

1 1.5 2 2.5 3 3.5 40

1

2

3

4

5

6

7

8

Áverage annual wind speed in m/sec

weibull constant k=2; decline 50 % for v=10 m/sec

decr

ease

in F

SC H

eigh

t %

Since collectors produce hot air by green house effect, to produce electric during the night, tight water-filled tubes are placed under the roof, as seen in fıgure 12. The water heats up during the daytime and emits its heat at night. These tubes are filled only once, no further water is needed, because the tubes remain closed after filling process.

Fig. 12 Principle of heat storage underneath the roof using water-filled black tubes .

The 1000m Solar Chimney in Mildura, Australia, will be the highest man-made structure on Earth, and can produce 200MW of electricity, providing power to 200,000 homes.Schematic seen of a construction of a chimney is in figure 14.

Fig. 14 Construction of a chimney

Details of the solar chimney are as follows:

Location: Mildura, AustraliaType: Solar Tower power plant with steel-reinforced concrete tower and steel/glass solar air collector (alternatively with polymer glazing)

Features: The base of the tower will be between 170 to 200 metres. The chimney is basically a very simple tube with wall thickness of 25cm, diameter of 150m and a height of 1000m. The collector roof will be 5000m in diameter.

Power: Up to 500 Gigawatt hours per yearCompany: Enviromission LtdConstruction time: About 18-24 monthsExpected completion date: 2005 .

• Thus a glass roof SAEPP, generating 20 GWh/year and rating power ~4.5 MW, of area ~1.0 square Km, and with an FSC of H~800m and d=40m, should cost ~63.20 Crore RUPEES

It provides electricity 24 hour a day from solar energy alone. No fuel and no cooling water is required. By FSC of 1000m, up to 1.2% of horizontal solar radiation can be converted into electricity. It is a low investment cost electricity generating technology, thus the direct cost of the produced KWh is low (less than 6 cents/KWh) The materials concrete, glass and steel necessary for the building of solar chimney power stations are everywhere in sufficient quantities. No ecological harm and no consumption of resources. The collector itself functions as a greenhouse and could be used for growing cash crops.It is shown that FSC Technology Power Plants is 5 to 6 times cheaper than CFC Technology Power Plants.

Some estimates say that the cost of generating electricity from a solar chimney is 5x more than from a gas turbine. Although fuel is not required, solar chimneys have a very high capital cost. The structure itself is massive and requires a lot of engineering expertise and materials to construct .

Solar chimney power stations could make important contributions to the energy supplies in Africa, Asia and Australia, because there is plenty of space and sunlight available there.

By little improvement in Efficiency and cost reduction, it can be best alternative

Future electricity demand could reach the 45000 T Wh. The necessary land for the 30 years FSC power plants is 1.000.000 Km2 (1000 Km X 1000 Km)

“Thermal engineering” by R.K.Rajput 6th edition ch.13 Draught A brief history of solar chimney.Retrieved 02.07.2009 from;

http://www.visionengineer.com/env/solar_flue.shtml Solar Chimney-Technology.Retrieved from;

http://www.sbp.de./de/html/projects/solar/aufwind/pages_auf/techno.htm. ‘Solar chimney cost estimation’ from www.solartower.org.uk/floating-papageorgiou.php Solar Chimney-Energy cost.Retrieved 10.11.2004 from;

http://www.sbp.de/de/html/projects/solar/aufwind/pages_auf/enprocos.htm www.floatingsolarchimney.gr/.../EEESD_Modular_solar_collector.

Efficiency of FSPs from Retrieved 10.11.2004 http://www.solar-tower.org.uk/floating-papageorgiou.php

Solar collector material; Retrieved 07.11.2008 from www.sciencedirect.com/science/article/pii/