INTRODUCTION
Repair and rehabilitation of an air condition has come into existence since after the discovery of air conditioner, which broke down after a period of time. In the previous days, the selection humility of air was very low in most part of the world this can be uncomfortable atmospheric condition to individuals.
There was need for Engineers and scientist to make research and come to the solution of this problem. They produced an appliance of bring cooling to the temperature known as an air conditioner. After a period of time it developed a fault and was about to be dumped.
Before a new one can be purchased there was need to repair and rehabilitate the faulty one to an acceptable standard for use again. of faulty air-conditioner I approach taken to restore the functionality of the air-conditioner environment and brings human comfort.

LITERATURE REVIEW
THE HISTORICAL BACKGROUND OF AIR CONDITIONING
Air-conditioning came about as a result of water someday that was hanged across windows and doors to provide evaporating cooling during hot and dry season. Air-conditioning came in place after the contribution of Lord Kelvin some of his works that lead to the discovery includes the following, establishment of the absolute temperature scale the law of conductibility of matter and others.
Few years later Willis carrier conducted a research, which was published in 1`911, provided the foundation for today’s air-conditioning industries. After this discovers it was left with the air-conditioner who was poisonous and uncomfortable till the year 1928 when a suitable refrigerant was found.
AIR-CONDITION APPLICATIONS
Air-conditioning is found in homes, industries, office building hospitals, banks, departmental stores etc.
It is used in an electric water cover which is use to cool city water. It is used by industries for packaging and shipping
Some air-conditioning systems operate as a heating system. It is used in residential central air conditioning.
Also used in automobiles air-conditioning it has a very wide range of application that made it demand to increase day by day.

AIR-CONDITIONER AND AIR- CONDITIONING: –
AIR-CONDITIONER: This is a device /machine that collects air from the environment purifies it, cool or heat and makes it more or less moisture. It also humidity and dehumidify air to supply sufficient outdoor air for ventilation. It conditions air up to a stand that it becomes less uncomfortable to human beings.
An air-conditioner also heats air to warm the environment during the dry season, it performs the cooling and waiting function depending on the types and user.
AIR-CONDITIONING: It is a process that is carried out by theatres-conditioner it is a means of cooling the temperature in a building to provide comfortable air temperature in theatres, stores, offices and homes when all the process in it known as air conditioning which result in an air conditioned.

AIR CONDITIONING SYSTEM OF THEIR TYPES
The smallest type of an air-conditioning system consists of a wall- mounted unit serving just the room in which it is located. In a large system the conditioned air is circulated around the whole building through ducts. It may consist of large metal tubes. In modern buildings, the structure itself often provides the ducts for circulating air
TYPES OF AIR CONDITIONING SYSTEMS: –
1. The all air type
2. The air –water type
3. The all water type
THE ALL AIR TYPES: A Central air-conditioning plant supplies all the air at a fixed temperature smaller units around the building provides the final temperature contral. An alternative is to have carrying warn air, this type of system is known as the all air-conditioning system.
In another kind of all-air system, controlling the amount of air supplied instead of its temperature, it is known as variable volume system regulates the temperature. If a building is to be cooled, the cold air must be provided but with this system, its temperature as not critical.
THE AIR-WATER TYPE: In the air water system, the central plant provides only the fresh air needed for ventilation for temperature contral, each circulating water kept at a table temperature.
THE ALL- WATER TYPE: In this system, only heat or the central plant supplies cooling water. Fresh air is brought in through ventilation provide in the room.

AIR- CONDITIOB TECHNIQUES/PRINCIPLES
In a large all air system, fresh air from outside is first drawn in through a duct. It is then mixed with recycled air from the building for only a certain amount of fresh air is required. This provides the oxygen that use. Up when we breath.
The mixed air passed through a filter section, which is of two stages. Stage 1 filter uses a substance like absorbent cotton. When the air passes through the fibers, any large dust particles get life behind.
Stage 2 filter removes fine particles such as ligartte smoke. It is usually done by pausing the air through a series of metal plates through, the fine particles are left chinning to the plates
COMPONENT OF AN AIR- CINDITIONER
There are many component that makes up an air –conditioner but below are the
DIAGRAM
Major four parts.
i) Compressor
ii) Condenser
iii) Metering device/drier strainer
iv) Evaporator
COMPRESSOR: The compressor is referred to as heart of the air –conditioner it pumps the refrigerant gas through the entire system.
It draws cool refrigerant gas through the suction line from the evaporator freezer coils. At the same time it compresses the gas and pumps it into the discharge line. There are various types of compressors graded according to their capacities and nature of work.
CLASSIFICATION ACCORDING TO THEIR NATURE OF WORK.
i) Reciprocating compressor
ii) Rotary compressor
iii) Centrifugal compressor
iv) Screw compressor
CLASSIFICATION ACCORDING TO THEIR CAPACITY
i) 1.0 horse power compressor
ii) 1.5 horse power compressor
iii) 2.0 horse power compressor
iv) 2.5 horse power compressor
CONDENSER: It is a plant of the system that transfer heat from air-conditioning system to a medium which absorbs and moves it to final disposal point. The condenser is the door through which unwanted heat flows out of the system. The condenser is the cooling coil for the hot refrigerant.
In this process, the refrigerant gas gives up the heat it removed from inside of the system and changes it into liquid state.
DRIER STRAINER/METERING DEVICE: –
In the drier strainer, as the hot refrigerant liquid leaves the condenser to enter the meting device a drier strainer removes any moisture or in purifies associated with it.
The metering device /capillary tube is carefully calibrated in length and inside diameter to meter the exact amount of liquid refrigerant flow required for each unit.
Evaporator: This is a device in the low pressure side of the air conditioning system, through which the unwanted heat flows into the system in order that it may be moved or transferred to the condenser. The evaporator is also called cooling unit.
OTHER COMPONENTS ARE: –
OVER LOAD AND RELAY: There are sensitive materials inside the air- conditioner, they serve for the purpose of controlling the compressor by tripping off when there is low or high voltage. They also supply current to the compressor.
THERMOSTAT: Is another sensitive plant of the air-conditioner, it supplies the system electrical current also trips off the compressor when the voltage is high and after prolonged use.
FLEXIBLE CABLES: This is the copper wire that carried the current from the current supply system with the help of pug to the air-conditioner.
JUNCTION BOX: It serves as a house of connecting wires which carries current to different section inside the air-conditioner like the bulled light inside the fridge and to the compressor.
FOAM THAT COVERS THE INTERNAL BODY: –
It is a substance that covers the internal body of the system so that cooled air from the evaporator will not be lost outside the building.
SWITCH: The switch controls the current coming into the system by putting it ON or OFF
ACCUMULATOR
The accumulator is a large cylinder to trap any refrigerant, which may not have changed to gas in the evaporator.
Since it is impossible to compress liquid.
The accumulator prevents liquid from entering compressor.
Heat exchanger: It is normally between the liquid the suction lines. It may be included or not included in the system
SUCTION LINE:
This is the line or tube through which the refrigerant gas leaves the accumulator to the compressor
CAPACITOR
This gives a charge to the compressor ruing. It reduces the ruing amperage by increasing the line voltage. Immediately the compressor starts, the capacitor gradually release the stored energy and this maintain the ruing of the compressor for long period.
FAN MOTOR
This help to circulate cool air in air-condition apartment and also help to remove heat from the refrigerant in the condenser by means of fan blades and blower.
BLOWER:
This unit send in the cool air into the room
FINS:
Evaporator or condenser fins provide additional surface area in contact with air movement to facilitates heat transfer on the surface of the two components by closing and opening.
DIAGRAM
SKETCH OF COMPONENT PART OF AN AIR CONDITIONER
ODOR FILTER: After undergoing temperature central, the air passes through an odor filter. It absorbs large number of Odor molecules from the air. It is been taken out to be reactivated from time to time.
SOUND ABSORBER: The conditioned air is normally more round the system by a centrifugal fan. Air taken in near the center of the fan is forced outward by it large curved blades. To prevent noise from the fan reaching the main part of the building the air is passed through a silencer. It contains the materials that absorb most of the sound energy from the air system. Air then flows along the ducts and enters the room through diffusers.

FEFRIGERANT:
In air- conditioning, the refrigerant commonly used is freon – 22 which can solidify or liquidity at moderately low temperature. It must it possess some certain properties which makes it fit for the process. A lot of refrigerant has been found very toxic to get a fine quality refrigerant, the following properties must seen.
1) It has a low boiling point
2) It is safe and non-toxic
3) It can liquidity or solidifies at moderate pressure and temperature.
4) It has high latent heat value
5) It has the ability to operate on a posture pressure
6) It can mix well with oil
7) It has no effect on moisture
8) It is non –corrosive to the metal of the air- condition

PURPOSES OF AIR – CONDITIONING
Air – conditioning is meant to create human comfort when taken in the atmospherics air
It was equally made for education purposes for student and non student to have the knowledge of air – conditioning and know the modes of its operation. It is used to make the oxygen we breathe comfortable.
It reduces hazards and environmental Des comfort in air.
It brings about controlled air home continuation and industrial ventilation’s.

WHY WE STUDY AIR- CONDITIONING
One may be opportune to work in a place where there is used of air –conditioning Eventually it develops a fault, you may be asked to work on it, having gone through the study, that will assist to do the work. Also in our various home the same thing is applicable.
We also study to know the function its component parts, how they carryout their duty and their makings it equally exposes to they type of maintenance needed after breakdown.
We are equally expected to get a simple and refined procedure in repairing and rehabilitate a faulty air conditioning system.
The basic of our study is to know all the basic maintenance of an air conditioner.