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WorksheetsREFRIGERATION & AIR CONDITIONING
Total questions: 74
Worksheet time: 45mins
Where would you expect to find a high pressure liquid within an AC system?
Between the compressor and the Thermal Xpansion Valve
Between the Thermal Xpansion Valve and the Evaporator
Between the compressor and the condenser
Between the Condenser and the Thermal Xpansion Valve
Which of the following is true about the optimum effective temperature for human comfort?
Same in winter and summer
Not dependent on season
Lower in winter than in summer
Higher in winter than in summer
The heat production from a normal healthy man when asleep is about _________
50 W
40 W
70 W
60 W
When the heat stored in the body is ________ the human body feels comfortable.
zero
infinite
positive
negative
Which of the following does not mainly a factor of dependency for the degree of warmth or cold?
Relative humidity
WBT
Air velocity
DBT
The effective temperature increases with a decrease in relative humidity at the same DBT.
True
False
What is the value of optimum effective temperature in winter?
17
18
19
20
What is the value of the optimum effective temperature in summer?
23
22
21
24
Which of the following provides the relationship between the optimum indoor effective temperature and optimum outdoor effective temperature?
Clothing
Occupants
Duration of stay
Climatic and seasonal differences
Which engine driven device compresses refrigerant and pumps it through the air conditioning system?
condenser
A/C lines
receiver/Dryer
compressor
- an A/C system component into which high-pressure liquid refrigerant flows and is temporarily stored and dehydrated, usually located between the condenser outlet and expansion valve.
compressor
receiver/dryer
accumulator
evaporator
- a chemical compound used in an A/C system to remove heat from the evaporator and transfer it to the condenser.
refrigerant
coolant
hydraulic oil
anti-freeze
- any of the various designs of fittings that allow service tools such as manifold gauges to be attached to an A/C system.
A/C lines
valve stem
service port
receiver/dryer
- to remove refrigerant from an A/C system and store it temporarily.
refrigerant recovery
coolant recovery
recharge
vacuum
Which of these is NOT a refrigerant used in automotive A/C sytems?
R1234yf
R12
R134a
R2D2
- a heat exchanger, in which low-pressure refrigerant flows and changes state, absorbing heat from the surrounding air and cools the passenger compartment.
compressor
condenser
receiver/dryer
evaporator
a device, similar to a radiator, in which the refrigerant loses heat and changes state from a high-pressure gas to a high-pressure liquid as it dissipates heat to the surrounding air.
condenser
compressor
evaporator
radiator
a valve that controls the flow of refrigerant, changing it from a high pressure liquid to a low pressure gas
service port
expansion valve
A/C lines
evaporator
Why must refrigerant be recovered from the A/C system before any A/C parts are replaced?
released refrigerant can cause personal injury
refrigerant is under pressure
to prevent refrigerant from escaping into the atmosphere
All of these
The process of lowering the temperature of a substance below that of its surroundings
air conditioning
condensation
evaporation
refrigeration
What is a heat exchanger that induces condensation on the pressurized refrigerant, so that it changes phase from a gas to a liquid?
condenser
evaporator
expansion valve
radiator
This removes pressure from the liquid refrigerant to allow expansion or change of state from a liquid to a vapor in the evaporator
condenser
evaporator
expansion valve
radiator
A chemical compound that is used as the heat carrier, which changes from gas to liquid and then back to gas in the refrigeration cycle
condenser coil
cooling coil
evaporator
refrigerant
What do you call the part of a refrigeration system in which the refrigerant absorbs heat and changes from a liquid to a gas.
condenser
evaporator
expansion valve
radiator
In what state is the refrigerant when it exits the condenser?
High pressure gas
Low pressure gas
High pressure liquid
Low pressure liquid
Which component squeezes the gas?
Compressor
Condenser
Evaporator
Thermal Xpansion Valve
Which system has moving parts?
Thermal Xpansion Valve
Fixed orifice
Variable Fixed Oriface
Where would you expect to find a high pressure liquid within an AC system?
Between the compressor and the Thermal Xpansion Valve
Between the Thermal Xpansion Valve and the Evaporator
Between the compressor and the condenser
Between the Condenser and the Thermal Xpansion Valve
What does a Thermal Xpansion Valve do?
Cleans, dries and filters the refrigerant
It controls the quantity of refrigerant entering the evaporator
Allows for an increase in pressure and temperature prior to entering the condenser
It acts as a safety device if the compressor is over pressuring the system
If contamination within an air conditioning system is suspected and a flushing procedure is to be carried out what component should also be changed?
Compressor
Receiver Drier
Thermal Xpansion Valve
Condenser
When leaving the compressor what state is the refrigerant in?
High Pressure, High Temperature gas
High Pressure, High Temperature liquid
Low Pressure, low Temperature gas
Low Pressure, low Temperature gas
The main components of the Air conditioning system are
Thermistor, condenser, flow control and an evaporator.
Fan blower, condenser, flow control and an evaporator.
Compressor, condenser, TXV and an evaporator.
Drainage, condenser, flow control and an evaporator.
Where does the low pressure liquid become a gas?
Evaporator
Condenser
TX valve
Compressor
The Simple Refrigeration cycle consists of .....
Three Mechanical parts
Four Mechanical parts
Five Mechanical parts
The name of part No. (1) is .......
Condenser
Evaporator
Compressor
The name part (2) is ...........
Compressor
Condenser
Capillary tube
The state of Refrigerant at point A is ........
Liquid
Vapor
Mixture ( liquid + vapor)
The state of Refrigerant at point B is ........
Mixture (vapor + liquid)
vapor
Liquid
The state of Refrigerant at point C is ........
Liquid
Vapor
Mixture (Liquid + Vapor )
The name of part No (3) is...........
Evaporator
Capillary tube
Compressor
The state of Refrigerant at point D is ........
Liquid
Mixture (Liquid +Vapor)
Vapor
The name of part No (4) is...........
Condenser
Capillary tube
Evaporator
The R 134a cylinder color is ........
Green
Light blue
White
What is the compressor known as?
The heart of the system.
The leg of the system.
The control system.
The air system.
What state is the refrigerant in when leaving the compressor?
100 percent Low Pressure, low temperature, superheated vapor
100 percent High Pressure, high temperature, superheated vapor
100 percent Low Pressure, low temperature subcooled Liquid
100 percent High Pressure, high temperature subcooled Liquid
What is the state of the refrigerant entering the compressor?
High pressure, high temperature, 100 percent superheated vapor
High pressure, high temperature, 100 percent subcooled liquid
Low pressure, low temperature, 100 percent superheated vapor
Low pressure, low temperature, 100 percent subcooled liquid
What is the temperature of the discharge line if you touch it.
Warm
Cool
Cold
Very Warm/Hot
What is the temperature of the suction line if you touch it?
Warm
Cold
Cool
Very Warm/Hot
What is the temperature of the liquid line if you touch it?
Warm
Cold
Cool
Very Warm/Hot
What is the temperature of the line at the outlet of the expansion device if you touch it?
Warm
Cold
Cool
Very Warm/Hot
What happens in the first 1/3 of the condenser?
Refrigerant subcools
Refrigerant superheats
Refrigerant changes to 25 percent vapor and 75 percent liquid
Refrigerant desuperheats
What is the job of the condenser?
Create flash gas, superheat, cool refrigerant
subcool, superheat, condense refrigerant
meter refrigerant, create flash gas, condense
desuperheat, condense, subcool refrigerant
What is the job of the expansion device?
begin changing liquid into vapor by creating a pressure drop
begin subcooling liquid by warming the vapor
begin superheating vapor by cooling the liquid
maintaining a constant pressure from the high side to the low side
What is the state of the refrigerant leaving the metering device in a refrigerator?
50 percent liquid and 50 percent vapor
25 percent liquid and 75 percent vapor
25 percent vapor and 75 percent liquid
100 percent liquid
What is the job of the evaporator?
Absorb heat from inside the refrigerator.
Absorb heat from outside the refrigerator.
change vapor to liquid
create flash gas
What is the state of the refrigerant leaving the evaporator?
100 percent liquid
50 percent liquid and 50 percent vapor
100 percent superheated vapor
100 percent subcooled liquid
