Tennessee Mechanical Contractor Exam
– Refrigeration Systems Exam Practice
Questions And Correct Answers
(Verified Answers) Plus Rationale 2026
Q&A| Instant Download Pdf
1. In a vapor-compression refrigeration system, which component is
primarily responsible for removing heat from the refrigerant vapor
and condensing it into a liquid?
A. Evaporator
B. Expansion valve
C. Compressor
D. Condenser
The condenser rejects heat from the high-pressure vapor refrigerant
to the surroundings, causing it to condense into a liquid state.
2. Which refrigerant property is most critical for determining the
pressure-temperature relationship in a refrigeration cycle?
A. Density
B. Saturation temperature
C. Specific volume
D. Viscosity
, The saturation temperature directly correlates with pressure in
refrigerants, forming the basis for system operation and control.
3. What is the primary function of the expansion valve in a refrigeration
system?
A. Increase refrigerant pressure
B. Remove heat from refrigerant
C. Reduce pressure and regulate flow into the evaporator
D. Compress refrigerant vapor
The expansion valve reduces pressure and controls refrigerant flow,
allowing it to evaporate at low temperatures in the evaporator.
4. Superheating of refrigerant vapor occurs in which component?
A. Condenser
B. Compressor
C. Evaporator
D. Receiver
Superheating occurs in the evaporator after all liquid refrigerant has
vaporized, ensuring only vapor enters the compressor.
5. What is the primary purpose of a receiver in a refrigeration system?
A. Remove moisture
B. Increase pressure
C. Store liquid refrigerant
D. Separate oil from refrigerant
A receiver holds excess liquid refrigerant, ensuring a consistent
supply to the expansion device.
6. Which device is used to remove moisture and contaminants from
refrigerant?
A. Accumulator
B. Receiver
C. Filter-drier
D. Sight glass
Filter-driers remove moisture and debris to prevent system damage
and corrosion.
, 7. What condition occurs when liquid refrigerant returns to the
compressor?
A. Superheating
B. Flash gas
C. Slugging
D. Subcooling
Slugging can damage compressors because liquid refrigerant is
incompressible.
8. Subcooling refers to:
A. Heating refrigerant above saturation
B. Cooling vapor refrigerant
C. Cooling liquid refrigerant below its saturation temperature
D. Reducing system pressure
Subcooling ensures that refrigerant remains in liquid form before
entering the expansion device.
9. Which refrigerant type has zero ozone depletion potential (ODP)?
A. CFCs
B. HCFCs
C. HFCs
D. Ammonia
HFCs do not contain chlorine, so they do not deplete the ozone layer.
10. What is the function of an accumulator in a refrigeration
system?
A. Store liquid refrigerant before expansion
B. Prevent liquid refrigerant from entering the compressor
C. Increase refrigerant pressure
D. Remove air from system
Accumulators trap excess liquid refrigerant and allow only vapor to
reach the compressor.
11. Which pressure is measured at the evaporator outlet?
A. High-side pressure
B. Discharge pressure
C. Suction pressure
– Refrigeration Systems Exam Practice
Questions And Correct Answers
(Verified Answers) Plus Rationale 2026
Q&A| Instant Download Pdf
1. In a vapor-compression refrigeration system, which component is
primarily responsible for removing heat from the refrigerant vapor
and condensing it into a liquid?
A. Evaporator
B. Expansion valve
C. Compressor
D. Condenser
The condenser rejects heat from the high-pressure vapor refrigerant
to the surroundings, causing it to condense into a liquid state.
2. Which refrigerant property is most critical for determining the
pressure-temperature relationship in a refrigeration cycle?
A. Density
B. Saturation temperature
C. Specific volume
D. Viscosity
, The saturation temperature directly correlates with pressure in
refrigerants, forming the basis for system operation and control.
3. What is the primary function of the expansion valve in a refrigeration
system?
A. Increase refrigerant pressure
B. Remove heat from refrigerant
C. Reduce pressure and regulate flow into the evaporator
D. Compress refrigerant vapor
The expansion valve reduces pressure and controls refrigerant flow,
allowing it to evaporate at low temperatures in the evaporator.
4. Superheating of refrigerant vapor occurs in which component?
A. Condenser
B. Compressor
C. Evaporator
D. Receiver
Superheating occurs in the evaporator after all liquid refrigerant has
vaporized, ensuring only vapor enters the compressor.
5. What is the primary purpose of a receiver in a refrigeration system?
A. Remove moisture
B. Increase pressure
C. Store liquid refrigerant
D. Separate oil from refrigerant
A receiver holds excess liquid refrigerant, ensuring a consistent
supply to the expansion device.
6. Which device is used to remove moisture and contaminants from
refrigerant?
A. Accumulator
B. Receiver
C. Filter-drier
D. Sight glass
Filter-driers remove moisture and debris to prevent system damage
and corrosion.
, 7. What condition occurs when liquid refrigerant returns to the
compressor?
A. Superheating
B. Flash gas
C. Slugging
D. Subcooling
Slugging can damage compressors because liquid refrigerant is
incompressible.
8. Subcooling refers to:
A. Heating refrigerant above saturation
B. Cooling vapor refrigerant
C. Cooling liquid refrigerant below its saturation temperature
D. Reducing system pressure
Subcooling ensures that refrigerant remains in liquid form before
entering the expansion device.
9. Which refrigerant type has zero ozone depletion potential (ODP)?
A. CFCs
B. HCFCs
C. HFCs
D. Ammonia
HFCs do not contain chlorine, so they do not deplete the ozone layer.
10. What is the function of an accumulator in a refrigeration
system?
A. Store liquid refrigerant before expansion
B. Prevent liquid refrigerant from entering the compressor
C. Increase refrigerant pressure
D. Remove air from system
Accumulators trap excess liquid refrigerant and allow only vapor to
reach the compressor.
11. Which pressure is measured at the evaporator outlet?
A. High-side pressure
B. Discharge pressure
C. Suction pressure
