HEATING AND HEATING AND AIR-CONDITIONINGAIR-CONDITIONING

INTRODUCTIONINTRODUCTION Today ventilation, heating and air-Today ventilation, heating and air-

conditioning systems are very important conditioning systems are very important elements for providing passenger comfort.elements for providing passenger comfort.

Ventilation and heating systems are Ventilation and heating systems are standard equipment on all passenger standard equipment on all passenger vehicles and air-conditioning the standard vehicles and air-conditioning the standard on some and available for nearly all.on some and available for nearly all.

The large number of vehicle with air The large number of vehicle with air conditioning plus recent changes in the conditioning plus recent changes in the methods used to cool a vehicle and to methods used to cool a vehicle and to service the systems makes a basic service the systems makes a basic knowledge of air-conditioning system.knowledge of air-conditioning system.

VENTILATION SYSTEMVENTILATION SYSTEM The ventilation system is to provide outside air to the The ventilation system is to provide outside air to the

passenger compartment.passenger compartment.

Among the several systems used to vent air to the Among the several systems used to vent air to the passenger compartment flow-through system is the passenger compartment flow-through system is the most common.most common.

In this the ram air flows into the car when it is In this the ram air flows into the car when it is moving.moving.

When the car is not moving , a steady flow of ram air When the car is not moving , a steady flow of ram air can be produced by the heater fan.can be produced by the heater fan.

AUTOMOTIVE HEATING AUTOMOTIVE HEATING SYSTEMSYSTEM

It has been designed to handle with It has been designed to handle with cooling system.cooling system.

The primary function is to provide The primary function is to provide comfortable temperature.comfortable temperature.

The primary component of the The primary component of the system are Heat core, Heater control system are Heat core, Heater control valve, The blower motor and the fan.valve, The blower motor and the fan.

AUTOMOTIVE HEATING SYSTEMAUTOMOTIVE HEATING SYSTEM

HEATER CONTROL VALVEHEATER CONTROL VALVE It controls the flow of It controls the flow of

coolant into the heater core coolant into the heater core from the engine.from the engine.

In a closed position, the In a closed position, the valve allows no flow of hot valve allows no flow of hot coolant to the heater core, coolant to the heater core, keeping it cool.keeping it cool.

In a open position, the allow In a open position, the allow heated coolant to circulate heated coolant to circulate through the heater core.through the heater core.

The blower motor is located The blower motor is located in heater housing assembly, in heater housing assembly, it is used to ensure air it is used to ensure air circulate through out the circulate through out the system. It speed is system. It speed is controlled by multiposition controlled by multiposition switch.switch.

THEORY OF AIR-CONDITIONINGTHEORY OF AIR-CONDITIONING All air conditioning system are based on three thee All air conditioning system are based on three thee

fundamental law of nature.fundamental law of nature.

HEAT FLOW : Greater the temperature difference between HEAT FLOW : Greater the temperature difference between the object, greater the heat flow.the object, greater the heat flow.

HEAT ABSORBTION: When changes from one state to HEAT ABSORBTION: When changes from one state to another, absorption or rejection of heat takes place.another, absorption or rejection of heat takes place.

PRESSURE AND BOILING POINTS: The greater the pressure PRESSURE AND BOILING POINTS: The greater the pressure on a substance, such as a liquid, changes its boiling point.on a substance, such as a liquid, changes its boiling point.

Greater the pressure higher the boiling point and lesser Greater the pressure higher the boiling point and lesser the pressure lower is the boiling point. the pressure lower is the boiling point.

REFRIGERANTS IN AIR REFRIGERANTS IN AIR CONDITIONING SYSTEMCONDITIONING SYSTEM

The substance used to remove heat from the The substance used to remove heat from the inside of an air conditioned vehicle is called inside of an air conditioned vehicle is called the refrigerant.the refrigerant.

Older refrigerant used in AC was R-12.Older refrigerant used in AC was R-12.

The latest AC system uses R-134a,this The latest AC system uses R-134a,this refrigerant may also referred to as SUVA.refrigerant may also referred to as SUVA.

It is an efficient then.It is an efficient then.

AIR CONDITIONING SYSTEM AIR CONDITIONING SYSTEM AND ITS COMPONENTAND ITS COMPONENT

COMPRESSORCOMPRESSOR

CONDENSERCONDENSER

EVAPORATOREVAPORATOR

RECEIVER/DRYERRECEIVER/DRYER

COMPRESSORCOMPRESSOR The compressor is heart of automotive AC The compressor is heart of automotive AC

system. It separates the high pressure and low system. It separates the high pressure and low pressure sides of the system.pressure sides of the system.

The primary function is to draw the low pressure The primary function is to draw the low pressure and low temperature vapor from the evaporator and low temperature vapor from the evaporator and compress this vapor into high-temperature, and compress this vapor into high-temperature, high pressure vapor.high pressure vapor.

The secondary function is to circulate the The secondary function is to circulate the refrigerant through the AC systemrefrigerant through the AC system

It is driven by the engines crankshaft via a drive It is driven by the engines crankshaft via a drive belt. belt.

Types of compressorTypes of compressor PISTON COMPRESSOR: This type of compressor PISTON COMPRESSOR: This type of compressor

can have its piston arranged in an in-line, axial, can have its piston arranged in an in-line, axial, radial or V-design. radial or V-design.

On the intake stroke, the refrigerant from the low On the intake stroke, the refrigerant from the low side of the system is drawn into the compressor.side of the system is drawn into the compressor.

During compression stroke, the refigerant is During compression stroke, the refigerant is compressed.compressed.

This increase both the pressure and the This increase both the pressure and the temperature of the heat carrying refrigerant. temperature of the heat carrying refrigerant.

ROTARY VANE COMPRESSOR: It does not ROTARY VANE COMPRESSOR: It does not have any piston. It consist of a rotor with have any piston. It consist of a rotor with several vanes and carefully shaped housingseveral vanes and carefully shaped housing

As the compressor shaft rotates, the vanes As the compressor shaft rotates, the vanes and housing foam chamber. The refrigerant and housing foam chamber. The refrigerant is drawn through the suction port in this is drawn through the suction port in this chimer, which becomes smaller as the rotor chimer, which becomes smaller as the rotor runs.runs.

The discharged port is located at the point The discharged port is located at the point where the gas is completely compressed. where the gas is completely compressed.

CONDENSERCONDENSER The condenser consists of coiled refrigerant tubing The condenser consists of coiled refrigerant tubing

mounted in series of thin cooling fins.mounted in series of thin cooling fins.

The purpose of condenser is to condense the high The purpose of condenser is to condense the high pressure, high temperature vapor coming from the pressure, high temperature vapor coming from the compressor.compressor.

It is achieved when the refrigerant vapor enters the It is achieved when the refrigerant vapor enters the inlet of condenser and hot vapor passes down to the inlet of condenser and hot vapor passes down to the condenser coil.condenser coil.

This process causes a large quantity of heat to be This process causes a large quantity of heat to be transferred to the outside air and the refrigerant to transferred to the outside air and the refrigerant to change from a high-pressure hot vapor to high-change from a high-pressure hot vapor to high-pressure warm liquid.pressure warm liquid.

RECEIVER/DRYERRECEIVER/DRYER

It is a storage tank for refrigerant It is a storage tank for refrigerant from the condenser.from the condenser.

Its upper part consist of ca bag of Its upper part consist of ca bag of DESICCANT.DESICCANT.

The lower portion contains a mesh The lower portion contains a mesh screen to absorb impurities.screen to absorb impurities.

EVAPORATOREVAPORATOR It consist of a refrigerant It consist of a refrigerant

coil mounted in a series of coil mounted in a series of thin cooling fins.thin cooling fins.

Upon receiving refrigerant Upon receiving refrigerant dryer, heat from the core dryer, heat from the core surface is lost to the surface is lost to the boiling and vaporizing boiling and vaporizing refrigerant, which is cooler refrigerant, which is cooler than the core, thereby, than the core, thereby, cooling the core.cooling the core.

The air passing over the The air passing over the evaporator loses its heat to evaporator loses its heat to cooler surface of the core, cooler surface of the core, there by cooling the air there by cooling the air inside the car.inside the car.

BASIC REFRIDGERARENT FLOW CYCLEBASIC REFRIDGERARENT FLOW CYCLE

REFRIGERANT LINESREFRIGERANT LINES Three major refrigerant lines: Three major refrigerant lines:

suction, liquid and discharge.suction, liquid and discharge.

Suction lines are located between Suction lines are located between the outlet side of the evaporator and the outlet side of the evaporator and inlet side of the compressor.inlet side of the compressor.

The liquid lines connect the The liquid lines connect the condenser to the receiver and condenser to the receiver and receiver to the inlet of the expansion receiver to the inlet of the expansion valve.valve.

CONCLUSIONCONCLUSION

In the busy world of today comfort In the busy world of today comfort plays a very important role in a plays a very important role in a man’s life.man’s life.

In the olden days men had to adjust In the olden days men had to adjust to the surroundings but in modern to the surroundings but in modern life science has developed a lot that life science has developed a lot that surroundings adjust to the men’s surroundings adjust to the men’s needs , i. e passenger comfort.needs , i. e passenger comfort.

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