Thermodynamics Questions and Answers – Vapor Compression Refrigeration Cycle-1

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This set of Thermodynamics Multiple Choice Questions & Answers (MCQs) focuses on “Vapor Compression Refrigeration Cycle-1”.

1. In vapour refrigeration cycle, which of the following is used for expansion?
a) expansion engine
b) throttling valve or capillary tube
c) both of the mentioned
d) none of the mentioned
View Answer

Answer: b
Explanation: This is because in expansion engine, power recovery is small and hence its cost is not justified.
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2. Which of the following operations occur in a vapour refrigeration cycle?
a) compression
b) cooling and condensing
c) expansion and evaporation
d) all of the mentioned
View Answer

Answer: d
Explanation: These are the processes which constitute the vapour refrigeration cycle.

3. Compression can be
a) dry compression
b) wet compression
c) both of the mentioned
d) none of the mentioned
View Answer

Answer: c
Explanation: Dry compression starts with saturated vapour and wet compression starts with wet vapour.
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4. Wet compression is preferred over dry compression.
a) true
b) false
View Answer

Answer: b
Explanation: Dry compression is always preferred.

5. Why is wet compression not preferred?
a) the liquid refrigerant can be trapped in the head of cylinder
b) this may damage the valves or cylinder head
c) liquid refrigerant can wash away the lubricating oil thus accelerating wear
d) all of the mentioned
View Answer

Answer: d
Explanation: These are the reasons why dry compression is preferred over wet compression.
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6. In the cooling and condensing, correct sequence of processes is
a) desuperheated->condensed->saturated liquid
b) desuperheated->saturated liquid->condensed
c) condensed->desuperheated->saturated liquid
d) saturated liquid->condensed->desuperheated
View Answer

Answer: a
Explanation: This is the correct sequence of processes and heat is transferred out.

7. The expansion process is
a) isentropic
b) reversible
c) adiabatic
d) all of the mentioned
View Answer

Answer: c
Explanation: The expansion process is adiabatic but not isentropic and is irreversible.
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8. The evaporation process is a
a) constant volume reversible process
b) constant pressure reversible process
c) adiabatic throttling process
d) reversible adiabatic process
View Answer

Answer: b
Explanation: This is the last process and it completes the cycle.

9. The evaporator produces the cooling or refrigerating effect.
a) true
b) false
View Answer

Answer: a
Explanation: It absorbs heat from the surroundings by evaporation.
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10. In the expansion process, which of the following remains constant?
a) work done
b) heat supplied
c) internal energy
d) enthalpy
View Answer

Answer: d
Explanation: The expansion is an adiabatic throttling process in which enthalpy remains unchanged.

11. The COP of cycle is given by(Q2=heat absorbed by evaporator and Wc=work done by compressor)
a) 1- (Q2/Wc)
b) 1- (Wc/Q2)
c) Q2/Wc
d) Wc/Q2
View Answer

Answer: c
Explanation: This is the COP of vapour refrigeration cycle.

12. One tonne of refrigeration is given as the rate of heat removal from surroundings equivalent to heat required for melting one tonne of ice in a day.
a) true
b) false
View Answer

Answer: a
Explanation: This is the definition of “one tonne of refrigeration”.

13. Which of the following is recommended in a refrigeration cycle?
a) superheating of vapour
b) subcooling of liquid
c) both of the mentioned
d) none of the mentioned
View Answer

Answer: c
Explanation: The superheating of vapour is done at evaporator outlet and subcooling of liquid occurs at condenser outlet.

14. Superheating of vapour and subcooling of liquid ____ the refrigerating effect.
a) decreases
b) increases
c) no change
d) none of the mentioned
View Answer

Answer: b
Explanation: The refrigerating effect is increased by using these techniques.

15. A condenser must ____ and then ____ the compressed refrigerant.
a) superheat, evaporate
b) desuperheat, evaporate
c) superheat, condense
d) desuperheat, condense
View Answer

Answer: d
Explanation: This is the function of a condenser.

Sanfoundry Global Education & Learning Series – Thermodynamics.
To practice all areas of Thermodynamics, here is complete set of 1000+ Multiple Choice Questions and Answers.

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Manish Bhojasia - Founder & CTO at Sanfoundry
Manish Bhojasia, a technology veteran with 20+ years @ Cisco & Wipro, is Founder and CTO at Sanfoundry. He is Linux Kernel Developer & SAN Architect and is passionate about competency developments in these areas. He lives in Bangalore and delivers focused training sessions to IT professionals in Linux Kernel, Linux Debugging, Linux Device Drivers, Linux Networking, Linux Storage, Advanced C Programming, SAN Storage Technologies, SCSI Internals & Storage Protocols such as iSCSI & Fiber Channel. Stay connected with him @ LinkedIn | Youtube | Instagram | Facebook | Twitter