An

Interim PROJECT REPORT

ON

SUBMITTED BY:

jk

ASHISH SHARMA

PROJECT UNDERTAKEN:

jk

SYMBOLS AND ABBREVIATIONS

A. Abbreviation

Abbreviation Full Form

1. LDR Light Dependent Resistor

2. RPM Revolutions per Minute

3.CR Concentration Ratio

4.PW Peta watt

5.DC Direct Current

6.AC Alternate Current

(i)

LIST OF FIGURES

Fig. No Title Page No.

1. Azimuthal angle and the Zenith angle 3

2. Solar energy received by earth 4

3. solar energy distribution across the earth 5

4. Single and Dual Axis Solar Tracker 6

5. Fresnel collector 7

6. PARABOLOID DISH COLLECTOR 7

7. DC GEAR MOTOR 9

8. Relay circuits 10

9. TRACKING CIRCUIT DIAGRAM 12

10. Gantt chart 13

(ii)

Table of Contents

SYMBOLS AND ABBREVIATIONS..................................................................................... i

A. Abbreviation .......................................................................................................................... i B. Symbols ................................................................................................................................ i

LIST OF FIGURES ........................................................................................................................ ii

CHAPTER 1 .................................................................................................................................................. 1

INTRODUCTION ........................................................................................................................ 1

CHAPTER 2 ..................................................................................................................................................3

TECHNOLOGY AND LITERATURE SURVEY ........... ......................................................... 3

CHAPTER 3 ................................................................................................................................................. 9

DESIGN ANALYSIS……………………………………………………………………...………9

OUTCOMES…………………………………………………………………………………………..…….13

REFERENCES……………………………………………………………………………………….……..15

CHAPTER 1

Introduction:

As we are on the verge of exhausting fossil fuels, we require some other promising

energy source. Solar energy is the best choice of choosing as the primary source of energy in the

future, as it is renewable, eco-friendly and safe to use. Earth receives close to 174 PW of energy.

Out of which 42 PW can be used without causing any adverse effect on the environment. There

are numerous ways of using this energy. It can be converted into thermal and electrical energy.

These energy can be further used for household purposes or complex industrial and research

fields. For using this energy we need to absorb and use this energy efficiently. Energy can be

absorbed by simple reflectors, but if we want to design a working apparatus which is much more

compact in size and has higher efficiency we would require concentrators which can concentrate

the rays at one point. These concentrators are parabolic surface, which can be either reflective or

refractive. Reflective are mirror type concentrator and lenses are refractive type concentrators.

Method of harnessing solar energy with the help of concentrators shows higher efficiency as

compared to flat geometry surfaces. But, there is a flaw in this method. As the sun will move

from east to west, role of concentrator will go into oblivion. As a matter of fact we would require

a mechanism which will move the concentrator and will align it normally to the sun-rays. If we

use concave mirror we will loose substantial amount of heat energy in process of reflection. But

movement of the reflector will be quite easier. This is because reflector will be only rotating.This

is where the role of our project comes.

First phase of our project deals with developing a tracking mechanism involving a relay

and a LDR. It will be done in mechatronic approach. Second phase of our project will deal with

using this energy in doing useful work. This work will be heating of water flowing in pipes.

In our design we would be using refractor type concentrator, which will be a lens.

Concentrating surface can be either by a convex lens or a concave mirror. Light will be made to

fall on a small part of pipe in which water will be flowing. Pipe on which light will be made

incident will of a high thermal conductance so that water gets efficiently heated up. As discussed

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light can be made to be concentrated either by the help of convex lens or a concave mirror. Both

have their pros and cons.

If we use concave mirror we will loose substantial amount of heat energy in process of

reflection. But movement of the reflector will be quite easier. This is because reflector will be

only rotating.

Another option that we have is of using a convex lens. It is quite certain that, this will

give a good efficiency as the concentrated radiation will be made to fall directly without any

reflection. There are two problems arising in its designing. Firstly, we will be required to

revolve the set up of lens about the point of concentration. Moving the set-up of lens with a

weight of nearly a kilo would be a challenging task. Secondly the frame of the set up will be

required to be quite durable. Since, procurement of a lens having a aperture of 10 inch and

radius of curvature as minimum as possible, we will be using for lenses of aperture 5 inch. By

increasing the size of aperture and decreasing the radius of curvature we will maximize the

concentration ratio. Concentration ratio is defined as the ratio of collector area and focused area.

Given as,

Concentration ratio=Collector area / Focused area

Light Dependent Resistor:

Light dependent Resistor is a resistance whose value increase with

intensity of light. We will use LDR to generate electric signal which will act as a feedback to the

circuit. This feedback will control the movement of our lens. We have wide varieties of LDR

present in the market. LDR’s are always extrinsic semiconductors which are formed doping of

impurities. Extrinsic semiconductors have better response and conductance in comparison to

intrinsic semiconductor. This is because in intrinsic semiconductor conductance takes place due

to excitation valence electrons, where as in extrinsic semiconductor impurities added increase the

free electron count and finally the conductance. Ideal material for this purpose is Cadmium

Sulfide (CdS). Other materials are Lead Sulfide and Indium Antimonide. Ge and Cu

photoconductors make best LDR’s, but are very expensive in nature.

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CHAPTER 2

Literature Surveyed:

Before starting with the concept of tracking sun we should be very clear

about the movement of earth with respect to sun and vice-versa. As per the general theory of

relativity given by Albert Einstein, no body is at absolute rest. Every body in this universe is

moving with respect to each other due gravitational forces being applied by one and another. As

a result if we consider earth to be at rest with respect to sun, we can presume sun to be moving

with respect to earth. Sun’s motion can be braked in two angles namely Azimuthal angle and the

Zenith angle. This can be graphically shown as:

Fig.1

Since our set up is a single axis, we will only track azimuth angle. Azimuth angle shows daily

variation and zenith angle shows only seasonal variation. Zenith angle can be tracked by the help

of levitating screws, as maximum variance in the zenith angle is 47 degree in a year[3].

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Solar energy received by earth:

1PW= 1015

W

Fig.2

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As shown in the diagram our earth receives such a huge amount of energy which goes wasted.

We receive close to 3,850,000 EJ per year. This energy is greater than twice the energy that we

will receive by combining rest of the fossil fuels left and mined Uranium combined. Our project

strives to make the maximum use of this energy in most efficient manner.

India being close to equator receives large amount of this energy as a result there is a good scope

for this technology.

Fig.3

Out of 174 PW we can use close to 42 PW without disturbing environment. If we divide this

energy by the total land area we will get a constant value of 1000W/m2. This value is known as

solar constant.

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Single and Dual Axis Solar Tracker:

As per the reference[3] SINGLE AXIS SOLAR TRACKER can be passive or active type. It has

manual elevation adjustment on a second axis which is turning throughout the year. In this only

azimuthal angle is controlled automatically. But DUAL AXIS SOLAR TRACKER is of active

type only. In this both azimuthal and zenith angles are automatically controlled.

fig.4

Open loop and closed loop controlled type tracker

As pre the reference[12] open loop and closed loop type trackers are classified as:

1) OPEN LOOP TYPE TRACKER: It does not require any feedback element.

With the help of solar tracker software all the sun positioning data is calculated and updated

regularly in a day with help of microcontroller.

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2) CLOSED LOOP TYPE TRACKER: There is feedback element in the system. When sensor

senses maximum intensity of light then the output from photo sensor fed to microcontroller. The

microcontroller controls the rotation of motor shaft.

Types of solar collectors:

Cylindrical parabolic collector : CR range 10 to 3

Fresenal collector : CR 10 TO 80

Fig.5

PARABOLOID DISH COLLECTOR:CR RANGES 100 TO1000

fig.6

Types of motor which can be used in our tracker:

1) DC Motor provides high torque to rotor inertia.

2) Ac motor.

3) Stepper motor moves in precise angular increments.

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4) A high reduction gear box can be used to provide a low rotation speed with high mechanical

torque.

Active and passive tracking:

As per the reference[9] there are two types of further classification

under close type of tracking, namely active tracking and passive tracking. Passive tracking

involves photosensitive materials which change their orientation as per the incident radiation.

They align themselves so as to achieve radiations normally. Advantage of using these materials

is that we can avoid using electronic components such as amplifiers, transistors,

microcontrollers, relays, etc. disadvantage of using these materials is the procurement cost, as

they are expensive and difficult to procure. Such prevailing smart materials are:

1) Freon based liquid[9]

2) Shape memory alloys[13] such as NiTi, CuZnAl, CuAlNi.

Active tracking on the other hand involves gears, sensors, microcontrollers, logic gates, relays,

etc. Trackers based on the active tracking track the sun by sensing its rays by the help of sensors.

Type of tracking Advantages Disadvantages

Open loop tracking 1) no change in path due to

external disturbances such as

clouds.

2) cost effective.

1) structure needs to be

constructed very durable.

2) time to time checks are

required.

Active tracking 1) They have good working life

2) easy to manufacture

3) Dual axis tracking can be

easily achieved.

1) External disturbances such as

clouds can cause major problem in

their path

Passive tracking 1)reliability is very high

2) no working cost

1) initial cost very high

2) can be only used for single

tracking.

CHAPTER 3

DESIGN ANALYSIS:

DC GEAR MOTOR

fig.7

A "DC Gear motor" is simply a DC Motor with an attached gearbox. The gearbox usually

converts a fast motor with limited torque into a slow output with increased torque. [14]

SPECIFICATIONS: 1.VOLTAGE=12V

2. RPM=5

RELAY

An electromechanical relay is a solenoid used to make or break mechanical contact between

electrical leads.

A relay is used to isolate one electrical circuit from another. It allows a low current control

circuit to make or break an electrically isolated high current circuit path.

A relay performs a function similar to power transistor switch circuit but has capability to switch

much larger currents.Because relay is electrically isolated, noise, induced voltages and ground

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faults occurring in the output circuit have minimal impact on the input circuit. [15]

Circuit symbol for a relay

fig8

In above figure, we can see that a relay consists of two separate and completely independent

circuits. The first is at the bottom and drives the electromagnet. In this circuit, a switch is

controlling power to the electromagnet. When the switch is on, the electromagnet is on, and it

attracts the armature (blue). The armature is acting as a switch in the second circuit. When the

electromagnet is energized, the armature completes the second circuit and the light is on. When

the electromagnet is not energized, the spring pulls the armature away and the circuit is not

complete. In that case, the light is dark. [16]

When we purchase relays, we generally have control over several variables:

The voltage and current that is needed to activate the armature

The maximum voltage and current that can run through the armature and the armature

contacts

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CONCENTRATING DEVICE:

We are using 4 convex lenses in a row instead of using a single lens because former gives 4

concentrating points where as later gives single point. Therefore, 4 lenses give better results as

compared to single lens.

1. DIAMETER OF EACH LENS: 10 TO 15cm

PIPE FOR WATER HEATING:

Pipe will be cylindrical in shape.

1. MATERIAL : Al or Cu and Plastic

2. DIAMETER : 4to5cm

3.PAINTED BLACK (to absorb more heat)

BASE:

All components such as lenses, motor, pipe etc. will be mounted on it.

1. MATERIAL: WOOD

2. DIMENSIONS: 24X24X2 inch

POWER SUPPLY:

A battery is used to supply power to drive the motor.

1. VOLTAGE: 12 volts

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TRACKING CIRCUIT DIAGRAM

Fig.9

WORKING:

Fig.9 shows sun tracking circuit .When there is no sunlight falling on the LDR, relay will be

operated. Relay acts as circuit maker or breaker, so it makes the circuit and drives the motor in

clockwise direction. As the LDR(enclosed in tube) mounted on the lens it detects light. Again

LDR operates relay and this time relay breaks the circuit ,as a result motor will not be driven.

Pipe having water is placed on the focus of lenses. Radiation of sun will be converged on the

pipe. This will result in the heating of water.

CALCULATION FOR STABILITY:

HORIZONTAL FORCES:

(1.58*11*sin33) + (1.7* 6* sin33) + (.5 *6 *sin33) + (m * 1 * sin33)

=8.98+5.55+1.6+.54 m

=16.13+.54m

VERTICAL FORCES:

(1.5 *12 *cos33) + (1.7 *12 *cos33) + (.5 *26* cos33) + (m* 1* cos33)

=15.09+17.10+10.90+.83m

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NO SUNLIGHT

LDR

RELAY MOTOR LENS BATTERY

=43.09+.83m

For stability ∑HF=∑VF

16.13+.54m = 43.09+.83m

Hence, mass of base doesn’t play any role in the stability of system.

OUTCOME AND CURRENT STATUS OF OUR STUDY

PERFORMED:

It has been decided to make a solar tracker with active tracking mechanism. It will be a single

axis solar tracker which will be tracking only azimuth angle for the concentration of sun rays we

will be using four convex lens with six inch aperture and low radius of curvature to maximize the

concentration ratio as much as possible. To drive this lens we will be using gear motor with high

reduction ratio so that we can achieve high driving torque and a very low rpm. Tracking will be

achieved by the help of circuit made by the help of relay and LDR. Our tracking mechanism will

be verified by heating flowing water in a metallic pipe. Inlet and outlet temperature will be noted

with the help of thermometer.

20/09/09 09/11/09 29/12/09 17/02/10

Task:1

Task:2

Task:3

Task:4

fig.10

Tasks

Start

date Duration days End date

Task:1 20/09/09 40 30/10/09

Task:2 01/11/09 30 01/12/09

Task:3 10/01/10 30 09/02/10

Task:4 09/02/10 20 01/03/10

Task 1: Study of prevailing solar trackers. Task 2: Designing of our solar tracker.

Task 3: Fabrication. Task 4: Testing and finalizing.

As per the Gantt chart we have now with our designing and will commence our work of

fabrication .

FUTURE WORK TO BE DONE

As our design is over we will now be moving on with the fabrication of our tracker. Parts will be

purchased and fabrication task will be initialized. Other tasks will be completed according to the

Gantt chart.

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Refrences

1) THE NEW SOLAR TRACKER WITH SHAPE MEMORY ALLOY ACTORS- V.Poulek

2) Machine vision as a method for solar tracker performance- M. Davis, J. Lawler, J. Coyle, A. Reich, T.

Williams.

3) Design, Manufacturing and Performance Test of a Solar Tracker made by embedded control.

4) Low cost two axis solar tracker with high precision positioning- A. Yazidil, Student Member, F.

Betin , Member, G. Notton , G.A. Capolinol.

5) Solar Panel energetic efficiency optomisation method based upon specific detector and micro system-

0. Oltu, P.L. Milea, M. Dragulinescu, E. Franti

6) Integrated Solar Tracker Positioning Unit in Distributed Grid-Feeding Inverters for CPV Power

Plants- Olivier Stalter, Bruno Burger

7) Field test and analysis: the behaviour 3j concentrator cells under the control of cell temperature.- H.S.

Lee", N.J. Ekins-Daukes', K. Araki'. Y. Kemmoku3. M. Yamaguchi.

8) Recent advances iin outdoor performances evaluation of PV systems.

9) Different tracking strategies for optimizing the energetic efficiency of a photovoltaic system.

10) Renewal and emerging technologies by Rakesh Ranjan.

11) Introduction to mechatronics and measurement system by David G Alciatore.

12) Automatic control-B.C.Nakra

13) Testing the new solar tracker with shape memory alloy actors.

14) Alciatore and Histand, “Introduction to Mechatronics and Measurement Systems”, pp 394-95

15) www.horrorseek.com

16) howstuffworks.com

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