Harnessing Sunlight

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DAY TIME ILLUMINATION

FOR

COMMERCIAL & RESIDENTIAL

APPLICATIONS

SISHU GRIHA MONTESSORI & HIGH SCHOOL

No.3, HAL III Stage, Bangalore-75, India

Project Team Vikram Raj (VIII Std)

Tejas Chandran (VIII Std) Suryanarayana Rao.S.R (Guide)

Harnessing SunlightHarnessing Sunlight

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TABLE OF CONTENTS 1. SYNOPSIS

2. INTRODUCTION Page 5

3. METHODOLOGY Page 8

4. EXPERIMENTS Page 11

5. DISCUSSION Page 15

6. CONCLUSION Page 24

7. REFERENCES Page 26

8. ACKNOWLEDGEMENT Page 28

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SYNOPSIS

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GENESIS OF THE IDEA: In December 2004, our school wanted to educate students on the potential harm of over consuming electricity during day and throw open a discussion in our science Club on potential ideas to overcome this issue. Our group thought that there should be a scientific method of bringing the light from the roof to illuminate the darker areas of the building in the lower floors where Sunlight cannot be accessed. Fancy lights and decorative table lamps use Optical Fibers powered by an ordinary electric bulb. This prompted us to extend this logic to a domestic lighting application. Can we transfer sunlight from the roof of a building, via decorative optical fibers, to light up the building? HYPOTHESIS: 1. Light can be transmitted through Optical fibers used in decorative lamps 2. We can leverage daytime Sunlight to charge these Optical fibers

3. We can use these “Solar charged optical fibers” as a Light Pipe for lighting the house METHODOLOGY & EXPERIMENTATION: 1. A multistoried building model was fabricated and optic fibers were fitted on its rooftop. These were connected to the lower floors. A parabolic reflector was used to focus light from an incandescent bulb on one end of the optic fibers. 2. The above model was modified by fitting an arch over it with a moving source of light. This simulated the movement of sun during the day. The intensity measurements were taken at different brightness of lamp and varying position of the lamp. The data

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recorded reveals that optical fibers can serve as light pipes to transfer light during the daytime. 3. We used these “Solar charged optical fibers” as a Light Pipe for lighting. The recording of the intensity measurements was repeated by placing the model on the rooftop exposing one end of the optic fibers to direct sunlight at different times during the day. The data reveals the correctness of the hypothesis. 4. Experiments were conducted to study the loss of intensity of light during transmission in optic fibre. DATA INTERPRETATION: Intensity measurements made with different brightness of light source and in sunlight reveal the practical feasibility of using optical fibers as light pipes. There is a loss in intensity during transmission in the optic fibers. This may be possibly due to characteristic property of the material and the range of wavelength of radiation. Light dependent resistors can be used for light intensity measurements by calibrating with a Lux meter. CONCLUSION: 1. Optic fibers used in decorative lamps can serve as light pipes

for transferring sun light to the interiors of the buildings. 2. It is possible to reduce the energy costs of electricity, wherein

maximum hour of utilization of electricity is during the day. 3. It is possible to enhance the utilization of natural sources of

energy and thereby move a step a forward to over come the energy crisis.

FUTURE SCOPE OF THE PROJECT: • Develop economic substitute for Optical Fibers • Develop Alternate material to reduce transmission losses • Commercialization

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INTRODUCTION

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The development of Science and Technology in the recent past has led to an all-round development of the society which includes the construction of high rise buildings in the already densely populated cities. These buildings are closely built and as a result, lower floors of the building are particularly deprived of deriving the advantage of Sunlight which is available for a major part of the working hours of many offices, schools, hospitals, residential apartments etc. As a result, electricity is used even during the day time. Due to the wastage of electricity which consumes natural resources like coal & water for its generation, a day may come when we are left with no coal and other petroleum products available for generating electricity and also for other related activities like transportation, communication etc. This would affect economic growth of a developing nation. In December 2004, our school wanted to educate students on the potential harm of over consuming electricity during day and throw open a discussion in our science Club on potential ideas to overcome this issue. Our group thought that there should be a scientific method of bringing the light from the roof to illuminate the darker areas of the building in the lower floors where Sunlight cannot be accessed. The following hypotheses are made:

• Light can be transferred through a bunch of optical fibers from the roof to the lower floors.

• The suitable reflector can be used to provide a parallel beam of light rays at one end of the optical fibers and thereby transmit light to the other end through a bunch of fibers laid along the wall of the building. One end of the fibers receives the sunlight and the other end is connected to the lower floors to improve illumination.

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Decorative Optical fibers The main aim of this project is to find an effective way of utilizing the Sunlight during the day to illuminate darker areas of the building, conserve the energy and thereby sustain our development despite the limited resources of fossil fuels. OPTICAL FIBER AND ITS STRUCTURE

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METHODOLOGY

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Model-1 ( Initial Stage – 2004 ) A Multi-storied flat, fabricated out of corrugated card board.

Model-2 (Current Stage) A Multi-storied flat, fabricated out of wood.

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STAGE - I

Initially a mirror arrangement was made similar to periscope was fitted to transfer light from roof top to lower floors. A table lamp with a bulb (200 watt) was used as a source of light. STAGE - II As the illumination in the above case was not satisfactory, a truncated parabolic reflector (Head light reflector) was used in place of concave reflector. A bunch of plastic optic fibers replaced mirror arrangement at the principal focus and illuminated by the same source of light. STAGE – III A parabolic reflector with a light source at the principal focus was mounted on an arch fitted over the roof of the flat. Light has a provision for movement along the arch and fitting at desired positions. In case of stage I and stage II, comparison of illumination was made manually. Initially, no intensity measurement was taken. Subsequently, a Lux meter was used to add value to the tests.

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EXPERIMENTS

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EXPERIMENT - 1 Calibration of resistance readings of Light Dependent Resistors with Lux Meter readings:

A set of readings at varying brightness of lamp were taken simultaneously with a Multi meter and Lux meter. This was done to develop a calibration curve for LDR readings which will help use LDR as an economic option for Lux meter for any intensity measurement.

Sl No Volts

LDR 1 LDR 2 Average

1 100 13.95 14.17 14.06 2

2 110 14.19 12.01 13.10 4

3 120 12.50 10.50 11.50 5

4 130 16.17 11.09 13.63 5

5 140 19.24 11.15 15.20 6

6 150 19.75 13.95 16.85 77 160 18.45 14.28 16.37 8

8 170 13.12 12.75 12.94 8

9 180 10.55 13.73 12.14 9

10 190 19.83 19.23 19.53 11

11 200 18.00 18.69 18.35 13

12 210 16.10 19.95 18.03 15

13 220 13.36 16.85 15.11 21

14 230 9.30 14.40 11.85 25

15 240 8.65 11.88 10.27 30

16 250 8.15 10.99 9.57 34

17 260 7.70 9.75 8.73 38

LDR READINGS(Kohm) Lux Meter

Reading

(LUX)

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EXPERIMENT – 2 Measurement of intensity with the position of the lamp at Different Positions along the arch: Intensity Reading at varying voltages were taken at different positions to simulate the movement of Sun in the horizon. Light dependent resistances were fitted in the ground floor and the readings of resistances were taken simultaneously with the help of a multi meter. The movement of the light source along the arch simulates the movement of the Sun in the horizon.

Sl. No DEGREE LDR-1 LDR-2 AVG-LDR LUXMETER

1 30.00 81.10 104.20 92.65 2.00

2 60.00 15.00 20.50 17.75 13.00

3 90.00 7.30 10.80 9.05 44.00

4 120.00 30.20 46.80 23.77 7.00

5 150.00 135.40 116.90 126.15 1.00


1 30.00 107.70 13.63 60.66 2.00

2 60.00 24.00 33.64 28.70 8.00

3 90.00 10.00 17.20 13.60 22.00

4 120.00 56.10 112.30 84.20 23.00

5 150.00 190.30 170.20 180.25 1.00


1 30.00 170.10 150.10 160.10 1.00

2 60.00 14.50 23.40 18.95 2.00

3 90.00 10.20 16.90 13.55 21.00

4 120.00 130.00 181.00 155.50 11.00

5 150.00 197.70 161.40 179.55 2.00


1 30.00 190.30 191.70 191.00 2.00

2 60.00 19.00 19.70 19.35 8.00

3 90.00 19.70 18.00 18.85 20.00

4 120.00 10.70 18.00 14.35 2.00

5 150.00 184.00 16.50 100.25 1.00

INTENSITY MEASUREMENTS AT 270 VOLTS AC




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EXPERIMENT – 3 Measurement of transmission losses in optic fibers: At varying voltages, intensity readings at the entry point and exit point were measured. The transmission data is given below.

WATT ENTRY EXIT % TRANSMITTED

( LUX) (LUX) ( %)

200 5500 25 0.45

100 3000 15 0.50

60 2500 31 1.24

40 911 22 2.41

EXPERIMENT – 4 Measurement of intensity of illumination in the Sun Light: The measurement of intensity of illumination was done with Lux Meter at different times during the day (0830-1830 Hrs). LUX

SL.NO TIME GROUND FLOOR

FIRST FLOOR

SECOND FLOOR

1 8:30am 27.0

124.0

76.0

2 9:30am 37.0

152.0

67.0

3 10:30am 281.0

292.0

207.0

4 11:30am 397.0

278.0

216.0

5 12:30pm 345.0

241.0

121.0

6 3.30pm 212.0

119.0

58.0

7 5.30pm 32.0

75.0

43.6

8 6:30pm 1.0

1.0

3.0

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DISCUSSION

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EXPERIMENT – 1 Simultaneous readings of light dependent resistors by Multi meter and Lux meter at different voltages helped in the development of calibration curve for utilizing light dependent resistors in place of Lux meter at reasonably good accuracy levels, as an economically viable option.

CALIBRATION CURVE

LDR & LUX METER

0.00

20.00

40.00

100

110

120

130

140

150

160

170

180

190

200

210

220

230

240

250

260

VOLTAGE

LD

R &

LU

X M

ET

ER

RE

AD

ING

LDR(kohms)

LUX(lux)

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EXPERIMENT – 2

INTENSITY MEASUREMENTS AT 270 V

92.65

9.05

23.77

126.15

7.00

1.00

17.75

2.00

13.00

44.00

0.00

50.00

100.00

150.00

ARCH POSITION (deg)

INT

EN

SIT

Y O

F L

IGH

T

LDR

LUX

30 60 90 120 150

18


60.66

13.60

84.20

180.25

23

1

28.70

28

22

0.00

50.00

100.00

150.00

200.00

ARCH POSITION (deg)

INT

EN

SIT

Y O

F L

IGH

T

LDR

LUX

30 60 90 120 150

19


160.10155.50

179.55

11

2

18.95

13.5512

21

0.00

50.00

100.00

150.00

200.00

ARCH POSITION (deg)

INT

EN

SIT

Y O

F L

IGH

T

LDR

LUX

30 60 90 120 150

20


191.00

14.35

100.25

2 1

19.3518.85

28

20

0.00

50.00

100.00

150.00

200.00

ARCH POSITION (deg)

INT

EN

SIT

Y O

F L

IGH

T

LDR

LUX

30 60 90 120 150

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• There is an increasing trend in the intensity readings from 30 degree position to 90 degree position and a decreasing trend from 90 degree position to 150 degree position.

• LDR readings show a decreasing trend from 30 degree position to 90 degree position and an increasing trend from 90 degree position to 150 degree position.

• Movement of the light source simulates the movement of the Sun in the horizon. Although the brightness of the lamp remains same at all positions, the intensity varies due to the variation in the amount of light received for different positions due to the physical limitations of the optical fibers’ location. Hence there is no reproducibility in readings for 30 degree and 150 degree position.

• In actual practice the amount of light received by the optical fibers changes due to the rotation of the earth on its own axis, although the brightness remains same through out the day. However, there is a gradual change in brightness of Sun due to the rotation of the earth in the elliptical orbit.

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EXPERIMENT – 3 Optical fibers are exposed to Sunlight and readings are taken at different times during the day. This shows how actually the light can be transmitted through optical fibers at different positions. The trend is similar to that of the observations made in the experiment-2 conducted with a lamp source. (There is an increasing trend in the intensity of light from 8 a.m to 12 noon and a decreasing trend from 12 noon to 4 p.m

INTENSITY MEASUREMENT IN

SUNLIGHT

124

152

292278

241

119

75

10

100

200

300

8:30 9:30 10:30 11:30 12:30 3:30 5:30 6:30

TIME

INT

EN

SIT

Y(l

ux

)

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EXPERIMENT – 4

The measurement of intensity at the entry and the exit points of the optical fibers show a reduction in the Lux meter readings, due to the transmission losses. The measured loss during transmission at different brightness of the lamp is indicated.

TRANSMISSION IN SUNLIGHT

0.310.35

0.61

0.460.53

0.20

0.40

0.60

0.80

1 2 3 4 5

TIME

%T

RA

NS

MIS

SIO

N

8:30 12:30 13:30 16:30 18:30

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CONCLUSION

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1. The experiments reveal that Plastic Optical fibers can be used

as light pipes for transferring sun light to the interiors of the buildings. This is further confirmed from the results of our ”Sunlight experiments”

2. This mechanism of lighting helps reduce cost of electricity

wherein a maximum hour of utilization of electricity is during the day.

3. The experiments reveal that the absorption loss during

transmission is high. This may be improved by exploring alternate low absorption material as a light Pipe.

4. This project can prompt opportunities for exploring more

economical material for optic fibers and commercialization of Harnessing Sunlight for Day time illumination for Commercial & residential applications.

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REFERENCES

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• World Book Encyclopedia

• Young Scientist Encyclopedia.

• Gregors family Encyclopedia.

• www.Wikipaedia.Org

• www.Howstuffworks.com

• Understanding fibre optics, by Jeff Hecht.

• DK Picturepedia.

• Inventions that changed the world.

• www.Google.Com

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ACKNOWLEDGEMENTS

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