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WorksheetsRAC Test No. 1- Basic Refrigeration Cycle
Total questions: 40
Worksheet time: 40mins
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
In a typical system, within which component would the evaporation of refrigerant take place?
Condenser
Receiver dryer
Evaporator
Compressor
Where does the low pressure liquid become a gas (vapour)?
Evaporator
Condenser
TX valve
Compressor
In what state is the refrigerant when it exits the condenser?
High pressure gas
Low pressure gas
High pressure liquid
Low pressure liquid
As refrigerant moves through the condenser it goes from _____ to ________
a Vapor to a Liquid
a Liquid to a Vapor
Low pressure Vapor to a low pressure vapor
High pressure liquid to a low pressure liquid
_______ 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
In which type of air refrigeration system a secondary compressor is used?
Reduced ambient type air refrigeration System
Regenerative type air refrigeration System
Simple air refrigeration System
Boot strap air refrigeration System
WHICH TYPE OF AIR COOLING SYSTEM IS USED FOR TRANSPORTATION?
Boot strap air cooling system
Reduced ambient air cooling system,
Reduced aircraft air cooling system,
Regenerative air cooling system.
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
The simple air cooling system is good for ---- flight speeds
low
high
ground level
sliding
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
In air conditioning of aeroplanes, using air as refrigerant, the cycle used is
Reversed Carnot cycle
Reversed Joule cycle
Reversed Brayton cycle
Reversed Otto cycle
The coefficient 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
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
When the lower temperature of a refrigerating machine is fixed, then the coefficient of performance can be improved by
(A) Operating the machine at higher speeds
(B) Operating the machine at lower speeds
(C) Raising the higher temperature
(D) Lowering the higher temperature
The C.O.P. of a heat pump working on a reversed Carnot cycle is ( T₂- high temperature, T₁ - Low Temperature)
(A) T₁/(T₂ - T₁)
(B) (T₂ - T₁)/T₁
(C) (T₁ - T₂)/T₁
(D) T₂/(T₂ - T₁)
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
What are the 4 basic components of all refrigeration system?
Fan motor, compressor, drain pan and condensor
Condensor, compressor, metering device and filter dryer
Evaporator, condensor, compressor and disconnect
Evaporator, condenser, compressor and metering device
1.to?
The process by which refrigerant is recycled to remove impurities.
Mobile refrigeration units.
The process by which refrigerant moves through a compressor.
The process by which circulating refrigerant absorbs heat in one location and moves it to another location.
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
A capillary tube serves the same purpose as a?
small water line
pressure relief line
expansion valve
bypass line
In which direction does refrigerant flow during a normal cooling cycle?
a. compressor to condenser
b. compressor to evaporator
c. compressor to filter drier
d. compressor to exit of evaporator
compressor to evaporator
compressor to filter drier
compressor to exit of evaporator
compressor to condenser
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
The Lowest temperature during the cycle,in a vapour compression system,occures after .......
A.Compression
B.Condensation
C.Expansion valve
C.Evaporation
A boot-strap air cooling system has
One heat exchanger
Two heat exchanger
Three heat exchanger
Four heat exchanger
