Refrigeration Cycles: Interactive Learning Quizzes for Thermodynamics

Question 1

In a vapor-compression refrigeration system, which component is typically absent?

Accepted Answer

Pump

Answer

Condenser

Answer

Evaporator

Answer

Expansion valve

Question 2

What is the definition of isentropic efficiency as applied to a compressor?

Accepted Answer

Ratio of actual work input to isentropic work input

Answer

Ratio of isentropic work input to actual work input

Answer

Ratio of actual COP to isentropic COP

Answer

Ratio of isentropic COP to actual COP

Question 3

What is the primary purpose of a capillary tube in a refrigeration cycle?

Accepted Answer

To regulate refrigerant flow rate

Answer

To remove contaminants from the refrigerant

Answer

To increase the pressure of the refrigerant

Answer

To decrease the pressure of the refrigerant

Question 4

Which type of refrigeration cycle is often employed in large-scale commercial refrigeration applications?

Accepted Answer

Cascade refrigeration cycle

Answer

Vapor-compression refrigeration cycle

Answer

Absorption refrigeration cycle

Answer

Stirling refrigeration cycle

Question 5

What is the function of a thermostatic expansion valve (TXV) in a refrigeration cycle?

Accepted Answer

To regulate refrigerant flow based on evaporator superheat

Answer

To regulate refrigerant flow based on evaporator pressure

Answer

To regulate refrigerant flow based on condenser pressure

Answer

To regulate refrigerant temperature

Question 6

In a vapor-compression refrigeration cycle, which component compresses the low-pressure refrigerant vapor to a higher pressure?

Accepted Answer

Compressor

Answer

Condenser

Answer

Evaporator

Answer

Expansion valve

Question 7

Which component is NOT part of a basic vapor-compression refrigeration cycle?

Accepted Answer

Turbine

Answer

Compressor

Answer

Condenser

Answer

Expansion valve

Question 8

During a refrigeration cycle, the refrigerant absorbs heat at the:

Accepted Answer

Evaporator

Answer

Condenser

Answer

Expansion valve

Answer

Compressor

Question 9

A refrigeration system with a higher COP:

Accepted Answer

Is more efficient

Answer

Consumes more energy

Answer

Produces less cooling effect

Answer

Operates at higher temperatures

Question 10

An advantage of using a multi-stage compression cycle in refrigeration is:

Accepted Answer

Higher COP

Answer

Reduced refrigerant leakage

Answer

Lower operating pressures

Answer

Smaller compressor size

Question 11

In a refrigeration system, the refrigerant charge should be:

Accepted Answer

Exactly as specified by the manufacturer

Answer

As much as possible

Answer

As little as possible

Answer

Dependent on the ambient temperature

Question 12

In a refrigeration cycle, which component serves as a heat exchanger for releasing heat to the surrounding environment?

Accepted Answer

Condenser

Answer

Compressor

Answer

Expansion valve

Answer

Evaporator

Question 13

During an isentropic compression process in a refrigeration system, what happens to the refrigerant's entropy?

Accepted Answer

Remains constant

Answer

Increases

Answer

Decreases

Answer

Fluctuates

Question 14

Which type of refrigerant is commonly employed in residential refrigerators?

Accepted Answer

Hydrofluorocarbons

Answer

Ammonia

Answer

Chlorofluorocarbons

Answer

Carbon dioxide

Question 15

Within the condenser component of a refrigeration cycle, which thermodynamic process primarily occurs?

Accepted Answer

Isobaric heat rejection

Answer

Adiabatic compression

Answer

Isochoric expansion

Answer

Isothermal compression

Question 16

The theoretical foundation of vapor-compression refrigeration cycles is based on which thermodynamic cycle?

Accepted Answer

Carnot cycle

Answer

Rankine cycle

Answer

Brayton cycle

Answer

Stirling cycle

Question 17

In a refrigeration cycle, what is the primary distinction between a single-stage and a two-stage system?

Accepted Answer

Single-stage systems utilize one compressor, while two-stage systems employ two compressors.

Accepted Answer

Two-stage systems generally exhibit enhanced efficiency compared to single-stage systems.

Answer

Two-stage systems operate at higher refrigerant pressures than single-stage systems.

Answer

Single-stage systems are typically used for larger cooling capacities than two-stage systems.

Question 18

In a refrigeration cycle, heat is absorbed by the refrigerant in the _____________ and released in the _____________

Accepted Answer

evaporator; condenser

Answer

condenser; evaporator

Answer

expansion valve; compressor

Answer

compressor; expansion valve

Question 19

Which of the following refrigerants contributes the least to ozone depletion?

Accepted Answer

R-290

Answer

R-410A

Answer

CFC-11

Answer

HFC-134a

Question 20

In an ideal refrigerant cycle, there is _____________ entropy change in the evaporator

Accepted Answer

no

Answer

negative

Answer

positive

Answer

equal to the entropy change in the condenser

Question 21

The primary function of a receiver in a refrigeration system is to _____________

Accepted Answer

store liquid refrigerant

Answer

reduce pressure fluctuations

Answer

cool the refrigerant

Answer

separate liquid and vapor refrigerant