81078515-Solar-Cooler.pdf

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KALI CHARAN NIGAM INSTITUTE OF TECHNOLOGY

Naraini Road, Banda (U.P.) 210001

(Approved by A.I.C.T.E. Delhi and Affiliated to G.B.T.U. Lucknow)

Session: 2010-2011

A PROJECT REPORT ON

SOLAR COOLERSubmitted in the partial Fulfillment of degree of

Bachelor of TechnologyIn

MECHANICAL ENGINEERINGUnder the guidance of

Mr. PRIYATAM SRIVASTAVA

Submitted By-: Submitted To-:

Vinay Kr. Singh (T.L.) Mr. Sailendra Yadav

Dhirendra Pratap Singh (Project Incharge)

Chandan Kr. Kushwaha

Rohit Kr. Mehrotra

DATE


ACKNOWLEDGEMENT

Many persons have contributed to make this project SOLAR COOLER a

reality. We would specially like to express our appreciation to Mr. PRIYATAM

SRIYASTAVA as a project guide for his unstinted support, encouragement and

his painstakingly and meticulous effort towards developing this project.

We acknowledge the help and cooperation received from all the faculty

members of KALICHARAN NIGAM INSTITUTE OF TECHNOLOGY.

Several colleagues and students have contributed directly and indirectly to the

contents this project, as they had given us numerous ideas. Their criticism gave us

the much-needed hints about the areas that needed elaboration and amendments

and also to present them with greater clarity.

We sincerely express our gratitude to Mr. JAI PRAKASH KUSHWAHA,

department incharge of MECHANICAL ENGINEERING, for his support and

help in the final preparation of this Report.

Finally, we wish to express our sincere thanks to all our family members,

especially our Parents for their constant moral support and encouragement.


DECLARATION

We hereby declare that this project SOLAR COOLER is genuine work carried

out by us and has not been presented by any other student in any college or

university. All the analysis done, word carried out and the project developed is the

result of the efforts made by us along with our team members.

Vinay Kumar Singh (T.L.)

Dhirendra Pratap Singh

Chandan Kumar Kushwaha

Rohit Kumar Mehrotra

DATE


SOLAR COOLER

Title of the


Table Of Contents

S.No. Contents Page No.

1. Introduction

2. Objective

3. Main components

Solar panel

Battery

D.C. motor

Fan

Cooler body

Cotton

4. Limitations

5. Conclusion

6. Bibliography


INTRODUCTION


Our project Solar Cooler is based on the concept of harvesting solar energy. As it is easily interpretable from the name of the project that it is based on the solar energy for satisfying its need of power source. The functionality of Solar Cooler is dissimilar as that of the traditional coolers. The solar energy is harvested and stored in a battery. This battery is in turn connected to the solar cooler for the power source. Then the water flows downwards from the higher potential towards cooler grass and cotton. The cooler grass and the cotton soaks the water and makes the air cool; even if the potential of water get lower it does not create any kind of hindrance in the smooth working of the solar cooler.

It do not creates the overheads of maintenance or purchasing of pump neither it has to be sent for servicing every season. The concept of solar cooler sounds good and economical hence almost every class of our society can bear its expenses. The best part is that it can be used even in those rural areas where, there is no facility of electricity supply. Thus in rural areas it can be widely used.

INTRODUCTION OF THE


Line Diagram of Solar Cooler

Solar Panel

Charging

System

Wires

Battery

Cooler Body


OBJECTIVE


Saving power and electricity.

Reducing the expenses made on maintenance of cooler by replacing the concept of pump.

Reducing the overheads creates by the electricity pump to lift the water when the voltage supply is low.

To reduce the electricity bills.

Minimizing the need of season wise servicing.

To enable people of those rural areas which do not have electricity supply to have cool air during summer days.

OBJECTIVE OF THE


MAIN COMPONENTSMAIN COMPONENTS


SOLAR PANEL


How Do Solar Panel Work?

A solar panel is a device that collects photons of sunlight, which are very small

packets of electromagnetic radiation energy, and converts them into electrical

current that can be used to power electrical loads.

Using solar panels is a very practical way to produce electricity for many

applications. The obvious would have to be off-grid living. Living off-grid means

living in a location that is not serviced by the main electric utility grid. Remote

homes and cabins benefit nicely from solar power systems. No longer is it

necessary to pay huge fees for the installation of electric utility poles and cabling

from the nearest main grid access point. A solar electric system is potentially less

expensive and can provide power for upwards of three decades if properly

maintained.

Besides the fact that solar panels make it possible to live off-grid, perhaps the

greatest benefit that you would enjoy from the use of solar power is that it is both a

clean and a renewable source of energy. With the advent of global climate change,

it has become more important that we do whatever we can to reduce the pressure

on our atmosphere from the emission of greenhouse gases. Solar panels have no

moving parts and require little maintenance. They are ruggedly built and last for

decades when properly maintained. Last, but not least, of the benefits of solar

panels and solar power is that, once a system has paid for its initial installation

costs, the electricity it produces for the remainder of the systems lifespan, which

SOLAR


could be as much as 15-20 years depending on the quality of the system, is

absolutely free! For grid-tie solar power system owners, the benefits begin from

the moment the system comes online, potentially eliminating monthly electric bills

or, and this is the best part, actually earning the systems owner additional income

from the electric company.

The solar cells you would have seen on satellites, calculators etc are photovoltaic

cells or modules (modules are a collection of solar cells electrically connected and

joined together in one frame). Photovoltaics, (photo = light, voltaic = electricity),

convert the energy of sunlight directly into electricity. Originally expensive and

only used in space, photovoltaics are now finding many applications on countless

devices, buildings etc were ever remote or free and environmentally sustainable

produced electricity is required.


Photovoltaic (PV) cells are made of special materials called semiconductors like

silicon, which is currently the most commonly used. Basically, when light shines

on the solar cell a percentage of this solar energy is absorbed into the

semiconductor material. This energy now inside the semiconductor knocks

electrons loose allowing them to flow freely. PV cells also all have one or more

electric fields that force electrons freed by light absorption to flow in a certain

direction. This flow of electrons is an electrical current. Metal contacts on the top

and bottom of the PV cell draw that current off to use to power external electrical

products such as lights, calculators etc. This current, combined with the cells

voltage (which is a result of its built-in electric field or fields), determines the

power (or wattage) that the solar cell can produce.


Solar panels collect clean renewable energy in the form of sunlight and convert

that light into electricity which can then be used to provide power for electrical

loads. Solar panels are comprised of several individual solar cells which are

themselves composed of layers of silicon, phosphorous (which provides the

negative charge), and boron (which provides the positive charge). Solar panels

absorb the photons and in doing so initiate an electric current. The resulting energy

generated from photons striking the surface of the solar panel allows electrons to

be knocked out of their atomic orbits and released into the electric field generated

by the solar cells.

An average home has more than enough roof area for the necessary number of

solar panels to produce enough solar electricity to supply all of its power needs.

Assisted by an inverter, a device that converts the direct current (or DC current),

generated by a solar panel into alternating current (or AC current), solar panel

arrays can be sized to meet the most demanding electrical load requirements. The

AC current can be used to power loads in your home or commercial building, your

recreational vehicle or your boat (RV/Marine Solar Panels), your remote cabin or

home, and remote traffic controls, telecommunications equipment, oil and gas flow

monitoring, RTU, SCADA, and much more.


BATTERY


The Battery (Dry Cell)

(How They Generate Electrical Power)

The common battery (dry cell) is a device that changes chemical energy to

electrical energy. Dry cells are widely used in toys, flashlights, portable radios,

cameras, hearing aids, and other devices in common use. A battery consists of an

outer case made of zinc (the negative electrode), a carbon rod in the center of the

cell (the positive electrode), and the space between them is filled with an

electrolyte paste. In operation the electrolyte, consisting of ground carbon,

Manganese dioxide, Sal ammoniac, and zinc chloride, causes the electrons to flow

and produce electricity.

How do batteries work?

Electricity is the flow of electrons through a circuit or conductive path like a wire.

Batteries have three parts, an anode (-), a cathode (+), and the electrolyte. The

cathode and anode (the positive and negative sides at either end of a smaller

battery) are hooked up to an electrical circuit.

Electron Flow

The chemical reaction in the battery causes a buildup of electrons at the anode.

This results in an electrical difference between the anode and the cathode. You can

think of this difference as an unstable build-up of the electrons. The electrons want

to rearrange themselves to get rid of this difference. But they do this in a certain

way. Electrons repel each other and try to go to a place with fewer electrons.

BATTERY


In a battery, the only place to go is to the cathode. But, the electrolyte keeps the

electrons from going straight from the anode to the cathode within the battery.

When the circuit is closed (a wire connects the cathode and the anode) the

electrons will be able to get to the cathode. In this example, the electrons go

through the wire, lighting the light bulb along the way. This is one way of

describing how electrical potential causes electrons to flow through the circuit.

However, these electrochemical processes change the chemicals in anode and

cathode to make them stop supplying electrons. So there is a limited amount of

power available in a battery.

When a battery is recharged, the direction of the flow of electrons is changed, the

electrochemical processes happen in reverse, and the anode and cathode are

restored to their original state and can again provide full power.

Batteries are used in many places such as in flashlights, cars, PCs, laptops, portable

MP3 players and cell phones. A battery is essentially a can full of chemicals that

cause chemical reactions that produce electrons. Looking at any battery, there are

generally two terminals. One terminal is marked (+), or positive, while the other is

marked (-), or negative. In an AA, C or D cell (normal flashlight batteries), the

ends of the battery are the terminals. In a large car battery, there are two heavy lead

posts that act as the terminals. Electrons collect on the negative terminal of the

battery. If a wire is connected between the negative and positive terminals, the

electrons will flow from the negative to the positive terminal as fast as it can wear

out the battery quickly and possibly cause an explosion.

Inside the battery, a chemical reaction produces the electrons. The speed of

electron production by this chemical reaction (the battery's internal resistance)

controls how many electrons can flow between the terminals. Electrons flow from


the battery into a wire, and must travel from the negative to the positive terminal

for the chemical reaction to take place. That is why a battery can sit on a shelf for a

year and still have plenty of power - unless electrons are flowing from the negative

to the positive terminal, the chemical reaction does not take place.

The "Dry-Cell" Battery Mechanism

The most common type of battery used today is the "dry cell" battery. There are

many different types of batteries ranging from the relatively large "flashlight"

batteries to the miniaturized versions used for wristwatches or calculators.

Although they vary widely in composition and form, they all work on the sample

principle. A "dry-cell" battery is essentially comprised of a metal electrode or

graphite rod (elemental carbon) surrounded by a moist electrolyte paste enclosed in

a metal cylinder as shown below.

In the most common type of dry cell battery, the cathode is composed of a form of

elemental carbon called graphite, which serves as a solid support for the reduction

half-reaction. In an acidic dry cell, the reduction reaction occurs within the moist

paste comprised of ammonium chloride (NH4Cl) and manganese dioxide (MnO2):


2 NH4+ + 2 MnO2 + 2e- ------> Mn2O3 + 2 NH3 + H2O

A thin zinc cylinder serves as the anode and it undergoes oxidation:

Zn (s) ---------------> Zn+2 + 2e-

This dry cell "couple" produces about 1.5 volts. (These "dry cells" can also be

linked in series to boost the voltage produced). In the alkaline version or "alkaline

battery", the ammonium chloride is replaced by KOH or NaOH and the half-cell

reactions are:

Zn + 2 OH- -------> ZnO + H2O + 2e-

2 MnO2 + 2e- + H2O -------> Mn2O3 + 2 OH-

The alkaline dry cell lasts much longer as the zinc anode corrodes less rapidly

under basic conditions than under acidic conditions.

Other types of dry cell batteries are the silver battery in which silver metal serves

as an inert cathode to support the reduction of silver oxide (Ag2O) and the

oxidation of zinc (anode) in a basic medium. The type of battery commonly used

for calculators is the mercury cell. In this type of battery, HgO serves as the

oxidizing agent (cathode) in a basic medium, while zinc metal serves as the anode.

Another type of battery is the nickel/cadmium battery, in which cadmium metal

serves as the anode and nickel oxide serves as the cathode in an alkaline medium.

Unlike the other types of dry cells described above, the nickel/cadmium cell can be

recharged like the lead-acid battery.


DC MOTOR


An electric motor uses electrical energy to produce mechanical energy, nearly

always by the interaction of magnetic fields and current-carrying conductors. The

reverse process that of using mechanical energy to produce electrical energy, is

accomplished by a generator or dynamo. Traction motors used on vehicles often

perform both tasks.

Electric motors are found in a myriad of uses such as industrial fans, blowers and

pumps, machine tools, household appliances, power tools, and computer disk

drives, among many other applications. Electric motors may be operated by direct

current from a battery in a portable device or motor vehicle, or from alternating

current from a central electrical distribution grid. The smallest motors may be

found in electric wristwatches. Medium-size motors of highly standardized

dimensions and characteristics provide convenient mechanical power for industrial

uses. The very largest electric motors are used for propulsion of large ships, and

for such purposes as pipeline compressors, with ratings in the thousands of

kilowatts. Electric motors may be classified by the source of electric power, by

their internal construction, and by application.

DC MOTOR


DC motor principle

DC motors consist of rotor-mounted windings (armature) and stationary windings

(field poles). In all DC motors, except permanent magnet motors, current must be

conducted to the armature windings by passing current through carbon brushes that

slide over a set of copper surfaces called a commutator, which is mounted on the

rotor. The commutator bars are soldered to armature coils. The brush/commutator

combination makes a sliding switch that energizes particular portions of the

armature, based on the position of the rotor. This process creates north and south

magnetic poles on the rotor that are attracted to or repelled by north and south

poles on the stator, which are formed by passing direct current through the field

windings. It's this magnetic attraction and repulsion that causes the rotor to rotate.

DC

Motor Operation


Current in DC Motor


Magnetic Field in DC Motor


Force in DC Motor


Torque in DC Motor


Torque on a Current Loop

The torque on a current-carrying coil, as in a DC motor, can be related to the

characteristics of the coil by the "magnetic moment" or "magnetic dipole moment".

The torque exerted by the magnetic force (including both sides of the coil) is given

by

The coil characteristics can be grouped as

called the magnetic moment of the loop, and the torque written as

The direction of the magnetic moment is perpendicular to the current loop in the

right-hand-rule direction, the direction of the normal to the loop in the illustration.

Considering torque as a vector quantity, this can be written as the vector product

since this torque acts perpendicular to the magnetic moment, then it can cause the

magnetic moment to process around the magnetic field at a characteristic

frequency called the Larmor frequency.

If you exerted the necessary torque to overcome the magnetic torque and rotate the

loop from angle zero to 180 degrees, you would do an amount of rotational work

given by the integral


The position where the magnetic moment is opposite to the magnetic field is said

to have a higher magnetic potential energy.


Torque Variation in DC Motor


Commutator and Brushes on DC Motor

To keep the torque on a DC motor from reversing every time the coil moves

through the plane perpendicular to the magnetic field, a split-ring device called a

commutator is used to reverse the current at that point. The electrical contacts to

the rotating ring are called "brushes" since copper brush contacts were used in

early motors. Modern motors normally use spring-loaded carbon contacts, but the

historical name for the contacts has persisted.

Types of DC motor

There are three types of DC motor:

DC series motor

DC shunt motor

DC compound motor


Series motor

In SERIES MOTORS, the field windings are connected in series with the

armature coil. The field strength varies with changes in armature current. When its

speed is reduced by a load, the series motor develops greater torque. Its starting

torque is greater than other types of dc motors. Its speed varies widely between

full-load and no-load. Unloaded operation of large machines is dangerous.

Shunt motor:-


In SHUNT MOTORS, the field windings are connected in parallel (shunt) across

the armature coil.

The field strength is independent of the armature current. Shunt-motor speed varies

only slightly with changes in load, and the starting torque is less than that of other

types of dc motors.

Shunt motors use high-resistance field windings connected in parallel with the

armature. Varying the field resistance changes the motor speed. Shunt motors are

prone to armature reaction, a distortion and weakening of the flux generated by the

poles that results in commutation problems evidenced by sparking at the brushes.

Installing additional poles, called interpoles, on the stator between the main poles

wired in series with the armature reduces armature reaction.

Compound motors:-


Here, the concept of the series and shunt designs are combined. The Figure above

shows one way of wiring a compound motor with interpoles. The blue lines

indicate the shunt field, the red lines designate the series field, and the green lines

show the interpole windings in series with the armature.

After more than a century, DC motors are still in widespread use, and thanks to

niche applications that show no signs of disappearing, they'll be around for many

years to come.


FAN


COOLER BODY


Cooler body is made of Tin.

Tin is a chemical element with the symbol Sn (Latin: stannum) and atomic

number 50. It is a main group metal in group 14 of the periodic table. Tin shows

chemical similarity to neighboring group 14 elements, germanium and lead and has

two possible oxidation states, +2 and the slightly more stable +4. Tin is the 49th

most abundant element and has, with 10 stable isotopes, the largest number of

stable isotopes in the periodic table. Tin is obtained chiefly from the mineral

cassiterite, where it occurs as tin dioxide, SnO2.

This silvery, malleable pool metal is not easily oxidized in air and is used to coat

other metals to prevent corrosion. The first alloy, used in large scale since 3000

BC, was bronze, an alloy of tin and copper. After 600 BC pure metallic tin was

produced. Pewter, which is an alloy of 85% to 90% tin with the remainder

commonly consisting of copper, antimony and lead, was used for flatware from the

Bronze Age until the 20th century. In modern times tin is used in many alloys,

most notably tin/lead soft solders, typically containing 60% or more of tin. Another

large application for tin is corrosion-resistant tin plating of steel. Because of its low

toxicity, tin-plated metal is also used for food packaging, giving the name to tin

cans, which are made mostly of steel

COOLER BODY


Cotton works on the principle of capillary tube (Meniscus height).

Height of a meniscus

The height h of a liquid column is given by:

where is the liquid-air surface tension (force/unit length), is the contact angle,

is the density of liquid (mass/volume), g is local gravitational field strength

(force/unit mass), and r is radius of tube (length).

For a water-filled glass tube in air at standard laboratory conditions, = 0.0728

N/m at 20 C, = 20 (0.35rad), is 1000 kg/m3, and g = 9.8 m/s2. For these

values, the height of the water column is

Thus for a 4 m (13 ft) diameter tube (radius 2 m (6.6 ft)), the water would rise an

unnoticeable 0.007 mm (0.00028 in). However, for a 4 cm (1.6 in) diameter tube

(radius 2 cm (0.79 in)), the water would rise 0.7 mm (0.028 in), and for a 0.4 mm

(0.016 in) diameter tube (radius 0.2 mm (0.0079 in)), the water would rise 70 mm

(2.8 in).

COTTON


LIMITATION


1- The main limitation is that the intensity of solar radiation is weather dependent. On cloudy day, the intensity of radiation is very low which is further affected by the dust, fog and smoke. There for it cannot work properly in cloudy days.

2- It covers only small area.

3- The initial cost of the system is quite high.

LIMITATIONS


CONCLUSION


Earlier in the traditional cooler, pump was used to lift the water up but in our concept of solar cooler the water flows down from the higher potential to downwards making the cotton and cooler grass wet. Thus this wet grass and cotton makes the air cool; even if the potential of water get lowers it does not create any kind of hindrance in the smooth working of the solar cooler.

Therefore from the above mentioned facts we can conclude that the concept of solar cooler is so cost effective and it do not creates the overheads of maintenance or purchasing of pump neither it has to be sent for servicing every season.

So, we can say that the concept of solar cooler sounds good and economical hence almost every class of our society can bear its expenses.

CONCLUSION


BIBLIOGRAPHY


Books

1). Non-Conventional Energy Sources - By G.D. RAI

2). Nonconventional Energy By Ashok V. Desai

3). Renewable energy sources and conversion technology By Bansal Keemann

BIBLIOGRAPHY


Current in DC MotorMagnetic Field in DC MotorForce in DC MotorTorque in DC MotorTorque on a Current LoopCommutator and Brushes on DC Motor

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81078515-Solar-Cooler.pdf