Presented by:
K.A.FENU

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HEATING AND AIR-CONDITIONING
INTRODUCTION
 Today ventilation, heating and air-conditioning systems are very important elements for providing passenger comfort.
 Ventilation and heating systems are standard equipment on all passenger vehicles and air-conditioning the standard on some and available for nearly all.
 The large number of vehicle with air conditioning plus recent changes in the methods used to cool a vehicle and to service the systems makes a basic knowledge of air-conditioning system.
VENTILATION SYSTEM
 The ventilation system is to provide outside air to the passenger compartment.
 Among the several systems used to vent air to the passenger compartment flow-through system is the most common.
 In this the ram air flows into the car when it is moving.
 When the car is not moving , a steady flow of ram air can be produced by the heater fan.
AUTOMOTIVE HEATING SYSTEM
 It has been designed to handle with cooling system.
 The primary function is to provide comfortable temperature.
 The primary component of the system are Heat core, Heater control valve, The blower motor and the fan.
HEATER CONTROL VALVE
 It controls the flow of coolant into the heater core from the engine.
 In a closed position, the valve allows no flow of hot coolant to the heater core, keeping it cool.
 In a open position, the allow heated coolant to circulate through the heater core.
 The blower motor is located in heater housing assembly, it is used to ensure air circulate through out the system. It speed is controlled by multiposition switch.
THEORY OF AIR-CONDITIONING
 All air conditioning system are based on three thee fundamental law of nature.
 HEAT FLOW : Greater the temperature difference between the object, greater the heat flow.
 HEAT ABSORBTION: When changes from one state to another, absorption or rejection of heat takes place.
 PRESSURE AND BOILING POINTS: The greater the pressure on a substance, such as a liquid, changes its boiling point.
 Greater the pressure higher the boiling point and lesser the pressure lower is the boiling point.
REFRIGERANTS IN AIR CONDITIONING SYSTEM
 The substance used to remove heat from the inside of an air conditioned vehicle is called the refrigerant.
 Older refrigerant used in AC was R-12.
 The latest AC system uses R-134a,this refrigerant may also referred to as SUVA.
 It is an efficient then.
AIR CONDITIONING SYSTEM AND ITS COMPONENT
 COMPRESSOR
 CONDENSER
 EVAPORATOR
 RECEIVER/DRYER
COMPRESSOR
 The compressor is heart of automotive AC system. It separates the high pressure and low pressure sides of the system.
 The primary function is to draw the low pressure and low temperature vapor from the evaporator and compress this vapor into high-temperature, high pressure vapor.
 The secondary function is to circulate the refrigerant through the AC system
 It is driven by the engines crankshaft via a drive belt.
Types of compressor
 PISTON COMPRESSOR: This type of compressor can have its piston arranged in an in-line, axial, radial or V-design.
 On the intake stroke, the refrigerant from the low side of the system is drawn into the compressor.
 During compression stroke, the refigerant is compressed.
 This increase both the pressure and the temperature of the heat carrying refrigerant.
 ROTARY VANE COMPRESSOR: It does not have any piston. It consist of a rotor with several vanes and carefully shaped housing
 As the compressor shaft rotates, the vanes and housing foam chamber. The refrigerant is drawn through the suction port in this chimer, which becomes smaller as the rotor runs.
 The discharged port is located at the point where the gas is completely compressed.
CONDENSER
 The condenser consists of coiled refrigerant tubing mounted in series of thin cooling fins.
 The purpose of condenser is to condense the high pressure, high temperature vapor coming from the compressor.
 It is achieved when the refrigerant vapor enters the inlet of condenser and hot vapor passes down to the condenser coil.
 This process causes a large quantity of heat to be transferred to the outside air and the refrigerant to change from a high-pressure hot vapor to high-pressure warm liquid.
RECEIVER/DRYER
 It is a storage tank for refrigerant from the condenser.
 Its upper part consist of ca bag of DESICCANT.
 The lower portion contains a mesh screen to absorb impurities.
EVAPORATOR
 It consist of a refrigerant coil mounted in a series of thin cooling fins.
 Upon receiving refrigerant dryer, heat from the core surface is lost to the boiling and vaporizing refrigerant, which is cooler than the core ,thereby, cooling the core.
 The air passing over the evaporator loses its heat to cooler surface of the core, there by cooling the air inside the car.
REFRIGERANT LINES
 Three major refrigerant lines: suction, liquid and discharge.
 Suction lines are located between the outlet side of the evaporator and inlet side of the compressor.
 The liquid lines connect the condenser to the receiver and receiver to the inlet of the expansion valve.
CONCLUSION
 In the busy world of today comfort plays a very important role in a man’s life.
 In the olden days men had to adjust to the surroundings but in modern life science has developed a lot that surroundings adjust to the men’s needs , i. e passenger comfort.