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WorksheetsREFRIGERATION
Total questions: 59
Worksheet time: 32mins
Small amounts of liquid returning to the compressor is called ___________?
Flood back
Flooded start
Slugging
Flooding compressor
Refrigerant changes from vapor to a liquid in which component?
Liquid line
Evaporator
Suction line
Condenser
Which of the following will cause the compressor work harder?
High suction pressure
Low suction pressure
Low charge
Low load
What is the compressor known as?
The heart of the system.
The leg of the system.
The control system.
The air system.
What is the temperature of the discharge line if you touch it.
Warm
Cool
Cold
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 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 refrigeration?
heating
drying
cooling
steaming
it decrease the pressure inside the system.
compressor
condenser
capillary tube
evaporator
What are the 4 basic components of all refrigeration system?
Fan motor, compressor, drain pan and condensor
Condensor, compressor, metering devise and filter dryer
Evaporator, condensor, compressor and disconnect
Evaporator, condenser, compressor and meter devise
What is Pressure and state of the refrigerant in the suction pipe?
High pressure vapor
Low pressure vapor
Low pressure liquid
High pressure liquid
State the 2 data points needed to determine subcooling
Condensing pressure and liquid line pressure.
Condensing pressure and liquid line temperature.
Evaporator pressure and suction line pressure.
Evaporator pressure and suction line temperature.
What is the function of the compressor?
create refrigerant..
Create pressure.
create a pressure drop
Heat exchanger
What is the function of the Meter device or txv?
Heat Exchanger.
A safety device.
Create more Pressure.
Create a pressure drop.
What is the function of the condenser in the cool mode?
Reject heat.
Absorb heat.
Mix the refrigerant.
Store refrigerant.
What is the function of the evaporator?
Reject heat.
Absorb Heat.
Create heat.
Mix refrigerant.
The Discharge Line travels between the?
Compressor and TXV
The Metering Device to the Compressor
Receiver and the Metering Device
Compressor and Condenser
Which is the correct order of refrigerant states starting with the discharge line?
Super heated Vapor, Condensing Vapor/Liquid mix, Sub cooled liquid, Flash Gas, Super heated Vapor
Condensing vapor, Flash gas, Sub cooled Liquid, Super heated vapor
Hot gas bypass, Freon Transfer, Liquid sublimation, Condensation.
Liquid, Vapor, Sub cooled vapor, Super heated Liquid
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
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 U.S. conventional unit of heat is the ___________.
BTU
Centigrade
Rankin
Celsius
How many Btu’s are in one ton of refrigeration in 24 hours?
12,000 Btu/24 hours
24,000 Btu/24 hours
300,000 Btu/24 hours
288,000 Btu/24 hours
A capillary tube serves the same purpose as a?
small water line
pressure relief line
expansion valve
bypass line
Hydrofluorocarbon (HFC) refrigerants contain:
chlorine, fluorine and carbon
chlorine, fluorine and hydrogen
hydrogen, chlorine and carbon
hydrogen, fluorine and carbon
One tonne of refrigeration is equal to
21 KJ/min
210 KJ/min
420 KJ/min
620 KJ/min
One tonne of refrigerating machine means that,
One tonne is the total mass of the machine
One tonne of refrigerant is used
One tonne of water can be converted into ice.
One tonne of ice when melts from and at 0oC in 24 hours, the refrigerating effect produced is equivalent to 210 KJ/min
In a refrigerating machine, heat rejected is ............ heat absorbed.
Equal to
Less than
Greater than
partially less than
Air refrigerator works on
Carnot cycle Rankine cycle .
Reversed Carnot cycle
Rankine cycle
Both Reversed Carnot cycle & Bell-Coleman cycle
The co-efficient of performance is always.......one
Equal to
less than
Greater than
None of the above
The sub-cooling in a refrigeration cycle ....
Does not alter C.O.P.
Increases C.O.P.
Decreases C.O.P.
None of the above
A reversible Carnot cycle used for refrigeration
comprises
Two isentropic and two adiabatic processes
Two isentropic and two constant volume processes
Two isentropic and two constant pressure process
Two isentropic and two isothermal processes
_______ decrease the pressure inside the system.
compressor
condenser
capillary tube
evaporator
The heat removing capacity of one tone of refrigeration is equal to?
210 Watt
210 kJ/hour
3.5 kJ/hour
3.5 W
The COP of a refrigerator is 4. What will be the COP of a heat pump if it is working between same source and sink temperature ?
2
3
4
5
One tonne of refrigerating machine means that,
One tonne is the total mass of the machine
One tonne of refrigerant is used
One tonne of water can be converted into ice.
One tonne of ice when melts from and at 0oC in 24 hours, the refrigerating effect produced is equivalent to 210 KJ/min
In a refrigeration system, the expansion device is connected to
(A) Compressor and condenser
(B) Condenser and receiver
(C) Receiver and evaporator
(D) Evaporator and compressor
The condition of refrigerant after passing through the condenser in a vapour compression system is
(A) Saturated liquid
(B) Wet vapour
(C) Dry saturated vapour
(D) Superheated vapour
A refrigerating system operating on reversed Brayton refrigeration cycle is used for maintaining 250 K. If the temperature at the end of constant pressure cooling is 300 K and rise in the temperature of air in the refrigerator is 50 K, then the net work of compression will be (assume air as working substance with Cp = 1 kJ/kg)
(A) 25 kJ/kg
(B) 50 kJ/kg
(C) 100 kJ/kg
(D) 125 kJ/kg
If a heat pump cycle operates between the condenser temperature of +27°C and evaporator temperature of -23°C, then the Carnot COP will be
(A) 0.2
(B) 1.2
(C) 5
(D) 6
A heat pump working on a reversed Carnot cycle has a C.O.P. of 5. It works as a refrigerator taking 1 kW of work input. The refrigerating effect will be
(A) 1 kW
(B) 4 kW
(C) 3 kW
(D) 2 kW
The highest temperature during the cycle,in a vapour compression system,occures after .......
A.Compression
B.Condensation
C.Expansion
C.Evaporation
A reversible engine has ideal thermal efficiency of 30%. When it is used as a refrigerating machine with all other conditions unchanged, the coefficient of performance will be
(A) 1.33
(B) 2.33
(C) 3.33
(D) 4.33
Effect of superheating on COP is
remains the same
increases
decreases
What is Pressure and state of the refrigerant in the suction pipe?
High pressure vapor
Low pressure vapor
Low pressure liquid
High pressure liquid
In what part of a refrigeration system does the refrigerant change from a hot high pressure vapor to a hot high pressure liquid?
Evaporator
Condenser
Liquid line
Suction line
Define refrigeration
It is the process of continuous cooling or extraction of heat to below that of the atmosphere from a substance with a help of the external work.
It is based on the second law of thermodynamics that the heat can made to flow from cold body to a hot body with the help of external source.
used to remove heat from the refrigerated space and reject it to atmosphere.
Below is the main component of refrigeration system EXCEPT:
Compressor
Evaporator
Condenser
Pump
Below are the process in refrigeration system EXCEPT
Compression
Condensation
Power
Evaporation
What is COP
Central of point
Coefficient of performance
Define tone of refrigeration
working fluid used in the refrigerator.
the standard unit of the refrigerator.
machine which produces cold.
process of continuous cooling or extraction of heat to below that of the atmosphere from a substance with a help of the external work.
The function of evaporator is :
draw the refrigerant from the evaporator through suction valve at low pressure and to force it to the condenser through exhaust valve at high pressure and temperature.
to control the rate of admission of refrigerants to the evaporator.
to condense the refrigerants at saturation temperature from vapour to liquid by transferring its latent heat to the water.
Receive the liquid refrigerants from the condenser through throttle valve and to evaporate it
Another simple method of refrigeration is evaporative cooling.
True
False
.The fluid that is vaporized is called the refrigerant
True
False
