INTERACTIVE DISTANCE LEARNING AIR CONDITIONING SPECIALIST:

AIR CONDITIONING FUNDAMENTALS

LEARNING GUIDE

CARS KNOWLEDGE NETWORK 6 – 9120 Leslie Street Richmond Hill, ON L4B 3J9 Phone: 905-709-1694 Fax: 905-709-1013

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AIR CONDITIONING FUNDAMENTALS The sole purpose of an A/C system is primarily for _____________________________. It does this by ___________________ the air temperature inside the passenger compartment and removing ________________________ and also cleans the air of dust and pollen particles.

HEAT Heat is the ____________________ in a substance. Heat can be measured by ________________________________________. One BTU is the amount of heat needed to raise______ lb. of ________________ one degree Fahrenheit at sea level. The law of heat transfer states that: heat always flows from an area of _________________ temperature to an area of ____________________ temperature. It also states that the greater the differences in temperature, the faster heat will flows.

There are different types of heat transfer and they are the following: 1) __________________________________________ 2) __________________________________________ 3) __________________________________________

The heat of vapourization law states: that a specific amount of heat is needed to change a __________________ into a vapour. Latent heat refers to the heat that is absorbed as the liquid changes state. It is also defined as the amount of heat required to cause this change to take place. Water will boil at _______________° F or at _______________°C at (101.4 kPa/14.7psi.

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Pressure-Temperature Relationships If the pressure acting on a liquid is increased the boiling point of the liquid will ________________________________, and lowering the pressure acting on a liquid will ______________________ its boiling point. The best cross reference is the cooling system when a radiator cap is put on a system it will bring the boiling point of water up to a higher temperature than 212° F, Utilize this formula 3° F for every ______ psi. + 212° F.

The boiling point of: R12 =-30° C or -22° F R134a= -27° C or -16° F

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Pressure will also have an effect on the temperature of the _______________________ and _________________. As pressure on the vapour is increased the temperature of the vapour will ____________. Raising the vapour temperature well above ambient will improve the ________________ transfer from condenser to ambient.

NOTES ________________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________

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Refrigerant Changes States

This basic movement of heat from one place to another is accomplished by: 1) ___________________________________ 2) ___________________________________ 3) ___________________________________

The major components that are utilized in all automotive A/C 1) __________________________________ 2) __________________________________ 3) __________________________________ 4) __________________________________ 5) __________________________________

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Label the above typical A/C system

List the components below and their effect on the state of change for that particular component:

1) _______________________ -____________________________________________ _____________________________________________________________________ _____________________________________________________________________ 2) _______________________- ____________________________________________ _____________________________________________________________________ _____________________________________________________________________ 3) _______________________- ____________________________________________ _____________________________________________________________________ _____________________________________________________________________ 4) _______________________- ____________________________________________ _____________________________________________________________________ _____________________________________________________________________ 5) _______________________- ____________________________________________ _____________________________________________________________________ _____________________________________________________________________

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Compressors The compressor performs a main function and that is to compress the ______-_________ refrigerant vapour from the evaporator into______________ pressure________________ and_________________ temperature vapour that leaves the compressor and travels to the condenser. There are several different types of compressors utilized in automotive applications and they are the following: 1) 2) 3) 4) 5)

____________________________________________ ____________________________________________ ____________________________________________ ____________________________________________ ____________________________________________

Typical Compressor

Cycling Clutch Compressors Cycling Clutch Compressors are basically controlled by being cycled ________ and _________ according to the pressure in the __________ side. When the compressor is cycled on, electric current energizes the electromagnetic clutch and the engine will drive the compressor. Adversely when the clutch is cycled off the clutch is de-energized and the pulley on the front of the compressor is allowed to _________________________.

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Condensers The main function of a condenser is to: ______________________________________ ________________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________

To accomplish this, _____________ high-pressure vapour enters the __________ of the condenser at the inlet. These vapours pass down through the condenser coils thus transferring heat to the coils and fins. These fins then transfer the heat to air passing over them. As this heat transfer is occurring the hot high -pressure vapour will be changing into a warm _________ pressure liquid. This warm liquid flows out the outlet at the ________________ of the condenser.

Typical Condenser A condenser may malfunction in several ways: 1) _____________________________________ 2) _____________________________________ 3) _____________________________________ 4) _____________________________________

Receiver-Dryer/Accumulator Dryers The main function of the Receiver Dryer is that it acts like a ________________ _________________ for the liquid refrigerant from the condenser. The liquid flows into the ______________ portion of the receiver tank, which contains a desiccant that will

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chemically dry by ________________________ moisture that has entered the system. Also located in the dryer is a filter that consists of a fine mesh screen.

Typical Accumulator-Dryer The accumulator-dryer is attached to the __________________________ at the outlet pipe. It will also act as a storage container, receiving refrigerant ________________ , vapour and oil. The primary function is to separate the _________________ from the liquid, vapour and oil, then release the vapour to the ________________________. There is also a desiccant bag, which will absorb moisture that may have entered the system.

Evaporator The main purpose of an Evaporator is to: ______________________________________ ________________________________________________________________________ ________________________________________________________________________

Typical Evaporator

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During A/C operation _____________________ refrigerant flows from the metering device into the ______________ pressure area of the evaporator. This causes a cool surface on the evaporator, as the air flows across the fins the air loses its heat to the much cooler surface of the evaporator fins. The _________________ that is present in the air stream will ___________________ on the cool surface and be drained off as water.

Evaporators can fail in several of the following ways: 1) _________________________ 2) _________________________ 3) _________________________ 4) _________________________ 5) _________________________ Superheat is defined as the difference between the evaporator inlet and outlet temperatures and is created in the evaporator as liquid refrigerant changes into vapour. Ideally , all liquid refrigerant boils before it reaches the outlet , the refrigerant temperature is above the boiling point. Refrigerant in the evaporator at 28.5 psi. has a temperature of -______°C (_______°F). As the refrigerant boils, the temperature of the vapour rises until, at the outlet it reaches ____°C (_______°F). The inlet to outlet differential(superheat) is 2.6 °C (_______°F).As the evaporator changes size so does the superheating.

NOTES ________________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________

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