Book 2 Chapter 17: Compression Refrigeration Systems

Question 1

Which of the following are the major components that comprise a basic mechanical refrigeration system?
A) Evaporator
B) Condenser
C) Compressor
D) All of the above

Answer 1

D) All of the above

Question 2

What brine temperature is used when cooling an ice surface?
A) -11ºC (12ºF)
B) -5ºC (23ºF)
C) -18ºC (0ºF)
D) -25ºC (-13ºF)

Answer 2

A) -11ºC (12ºF)

Question 3

What is the lowest temperature at which a brine solution can operate before it freezes when used in an indirect system?
A) -10ºC (14ºF)
B) 15ºC (59ºF)
C) -50ºC (-58ºF)
D) -25ºC (-13ºF)

Answer 3

C) -50ºC (-58ºF)

Question 4

What is the term used to describe the device used on a centrifugal chiller to improve efficiency and provide an intercooling effect?
A) Compressor
B) Economizer
C) Expansion valve
D) Condenser

Answer 4

B) Economizer

Question 5

Which of the following is not a component of the low pressure side of the system?
A) The downstream side of the regulating valve
B) The accumulator
C) Compressor discharge
D) The evaporator
E) Compressor inlet

Answer 5

C) Compressor discharge

Question 6

The function of the condenser is to:
A) Lower the liquid refrigerant pressure
B) Pressurize low pressure refrigerant vapour
C) Vaporize the liquid refrigerant
D) Change high pressure refrigerant vapour to liquid
E) Vent off vaporized refrigerant

Answer 6

D) Change high pressure refrigerant vapour to liquid

Question 7

Which of the following are principle parts in a closed cycle compression refrigeration system?
1. Absorber
2. Evaporator
3. Compressor
4. Condenser

A) 3 only
B) 1,2,3
C) 1,2
D) 1,2,4
E) 2,3,4

Answer 7

E) 2,3,4

Question 8

Which of the following statements about high-side pressure and temperature is true?
A) The heat flow is from the cooling medium to the hot refrigerant
B) The condensation temperature of the refrigerant will be higher if the pressure of the vaporized refrigerant is lowered
C) None of the above
D) The condenser functions by taking latent heat from the surrounding air and adding it as sensible heat to the refrigerant
E) The condensing temperature of the vapour is 15º-30ºC higher than the temperature of the medium used in the condenser

Answer 8

E) The condensing temperature of the vapour is 15º-30ºC higher than the temperature of the medium used in the condenser

Question 9

Brine used for producing ice is generally a solution of:
A) Calcium chloride
B) Sodium chloride
C) Glycol
D) Alcohol
E) Sodium sulphite

Answer 9

A) Calcium chloride

Question 10

The heat lost by the brine in the evaporator, must be equal to the heat:
A) Gained by the refrigerant
B) Gained by the receiver
C) Produced by the compressor
D) Lost by the condenser
E) Gained by the condenser

Answer 10

A) Gained by the refrigerant

Question 11

Which of the following statements about a refrigeration system that circulates warm brine back to a chiller tank is true?
A) The system is a direct refrigeration system
B) The condenser in the system is located in direct contact with the material being refrigerated
C) The evaporator in the system is located in direct contact with the material being refrigerated
D) The evaporator cools the brine
E) The brine or water is the refrigerant

Answer 11

D) The evaporator cools the brine

Question 12

For a direct expansion system which of the following statements is true?
A) The evaporator can be located in air circulating ducts communicating with the material or space being refrigerated
B) For large system calcium chloride brine is cooled by the evaporator then pumped to the area being refrigerated
C) The evaporator in this system is never in direct contact with the material or space being refrigerated
D) Water cooled by the chiller evaporation coils is used to refrigerate at temperature below 0ºC
E) Chilled water is pumped to unit ventilators

Answer 12

A) The evaporator can be located in air circulating ducts communicating with the material or space being refrigerated

Question 13

Which of the following statements about low-side pressure and temperature is false?
A) The evaporation temperature of the refrigerant will be lower if the evaporator lowers the refrigerant pressure
B) All of the above
C) The low side pressure depends on the type of evaporator
D) The evaporation temperature of the refrigerant should be 5º-10ºC higher than that of the cooled medium
E) For a given amount of heat transfer an oversized evaporator can be operated at a higher temperature

Answer 13

D) The evaporation temperature of the refrigerant should be 5º-10ºC higher than that of the cooled medium

Question 14

The primary difference between direct and indirect refrigeration systems is the:
A) Compressor location
B) Type of heat transfer medium
C) Evaporator pressure
D) Location of the medium being cooled
E) Type of refrigerant

Answer 14

D) Location of the medium being cooled

Question 15

In actual refrigeration systems there will be a gradual pressure drop through each side of the system due to:
A) The economizer
B) Coefficients of expansion of the system components
C) Friction in the evaporator, condenser, and piping
D) Superheating effects
E) Decomposition of refrigerants

Answer 15

C) Friction in the evaporator, condenser, and piping

Question 16

In the compression refrigeration system the pressure in the evaporator is kept low by the:
A) Regenerator
B) Compressor
C) Evaporator
D) Condenser
E) Absorber

Answer 16

B) Compressor

Question 17

In the compression refrigeration system the work done on the vapour during compression will cause an increase in the temperature of the vapour to a value that is higher than the saturation temperature corresponding to the vapours pressure. The condition of the vapour is said to be:
A) Super tempered
B) Superheated
C) Sub cooled
D) Super saturated
E) Super cooled

Answer 17

B) Superheated

Question 18

A simple closed-cycle compression refrigeration system does NOT contain which of the following principle components?
A) Condenser
B) Evaporator
C) Liquid receiver
D) Absorber

Answer 18

E) Absorber

Question 19

In the compression refrigeration system a controlled amount of ________ refrigerant passes through the regulating valve into the evaporator.
A) High-pressure, high temperature vapour
B) High-pressure, low-temperature vapour
C) High-pressure, low-temperature liquid
D) High-pressure, high-temperature liquid
E) Low-pressure, high-temperature liquid

Answer 19

D) High-pressure, high-temperature liquid

Question 20

Which of the following is not a principle component of a simple closed-cycle compression refrigeration system?
A) Evaporator
B) Condenser
C) Liquid receiver
D) Liquid refrigerant control or regulating valve
E) Regenerator

Answer 20

E) Regenerator

Question 21

What is the term used to describe the devices used on a centrifugal chiller to improve efficiency and provide an intercooling effect?
A) Condenser
B) Expansion valve
C) Evaporator
D) Compressor
E) Economizer

Answer 21

E) Economizer

Question 22

As a general rule in the compression refrigeration system the evaporation temperature should be between________ lower than that of the cooled medium.
A) 5ºC (41ºF) and 10ºC (50ºF)
B) 15ºC (59ºF) and 20ºC (68ºF)
C) 10ºC (50ºF) and 15ºC (59ºF)
D) 0ºC (32ºF) and 5ºC (41ºF)
E) 20ºC (68ºF) and 25ºC (77ºF)

Answer 22

A) 5ºC (41ºF) and 10ºC (50ºF)

Question 23

One of the classes of closed cycle mechanical refrigeration systems is the:
A) Regeneration system
B) Absorption system
C) Condensation system
D) Evaporation system
E) Expansion system

Answer 23

B) Absorption system

Question 24

In the compression refrigeration system the high-pressure, superheated vapour is discharged into the condenser where it gives up, first, the sensible heat (superheat) caused by the compression and second, the _________ of condensation of the refrigerant vapour.
A) Latent temperature
B) Latent heat
C) Enthalpy
D) Sensible temperature
E) Sensible heat

Answer 24

B) Latent heat

Question 25

The low-pressure side of the compression refrigeration system includes all except the:
A) Downstream of the regulating valve
B) Suction of the compressor
C) All interconnected tubing and piping
D) Condenser
E) Evaporator

Answer 25

D) Condenser