Book 2 Chapter 19: Heat Exchangers For Refrigeration Systems

Question 1

Bare tube evaporators are used when the space temperature is maintained below ____________.
A) 1ºC (34ºF)
B) 10ºC (50ºF)
C) 5ºC (41ºF)
D) 20ºC (68ºF)

Answer 1

A) 1ºC (34ºF)

Question 2

Which of the following are types of condensers?
A) Air-cooled
B) Water-cooled
C) Evaporative
D) All of the above

Answer 2

D) All of the above

Question 3

Evaporative condensers are favoured in locations where it is necessary to conserve on:
A) Power
B) Space
C) Water
D) Noise

Answer 3

C) Water

Question 4

Scale forming chemicals may deposit on the waterside surfaces of which of the following condensers?
A) Evaporative
B) Double tube
C) Shell and tube
D) All of the above

Answer 4

D) All of the above

Question 5

An evaporator that increases heat exchange surface area by crimping thin metal plates to its form is the:
A) Bare tube evaporator
B) Plate surface evaporator
C) Finned tube evaporator
D) Shell and tube evaporator
E) All of the above

Answer 5

C) Finned tube evaporator

Question 6

The refrigeration plant condenser which is very expensive to clean which requires the tubes to be cleaned with acid and neutralized is the:
A) Shell and coil condenser
B) Shell and tube condenser
C) Evaporative condensers
D) Baffle condenser
E) Air cooled

Answer 6

A) Shell and coil condenser

Question 7

The amount of water used in an evaporative condenser is only a small percentage of that used in a water-cooled condenser of the same capacity. This is due primarily to what?
A) Water evaporating requires a large amount of latent heat
B) The evaporating condensers spray refrigerated water onto condensing coil
C) Evaporating condensers also use air to cool the refrigerant
D) Water being recirculated
E) None of the above

Answer 7

D) Water being recirculated

Question 8

An evaporative condenser contains condensing coils:
A) Enclosed in a cabinet
B) Contained in a shell
C) Covered in brine
D) Immersed in water
E) Which are dry

Answer 8

A) Enclosed in a cabinet

Question 9

An evaporator that contains the amount of liquid/vapour mixture of refrigerant necessary at any time is what type of evaporator?
A) Flooded evaporator
B) A multi coil evaporator
C) Dry evaporator
D) All of the above
E) None of the above

Answer 9

C) Dry evaporator

Question 10

With respect to water cooled condensers, an evaporative condenser’s water consumption can be up to:
A) 15% less
B) 90% less
C) 55% less
D) 75% less
E) 25% less

Answer 10

B) 90% less

Question 11

Air-cooled condensers of large capacity are found mainly in which of the following locations?
A) Closed rooms with low air circulation
B) Warm dry rooms
C) Roof tops
D) All of the above

Answer 11

C) Roof tops

Question 12

In an evaporative condenser, water is pumped through spray elements above the condensing coils and:
A) Air is sucked through by natural draft created
B) Fans draw air from the bottom of the coils
C) The water is piped to waste
D) The water is used to heat freezer floors
E) Fans draw air through the bottom of the coils

Answer 12

E) Fans draw air through the bottom of the coils

Question 13

With respect to the dry evaporator, the heat transfer rate of the flooded evaporator is:
A) Lower
B) 10% less
C) The same
D) Higher
E) 80% less

Answer 13

D) Higher

Question 14

Defective refrigeration plant condenser operation is a result of the presence of all of the following except:
A) Scale forming chemicals
B) Dirty cooling water
C) Loss of refrigerant
D) Non-condensable gases
E) Low coolant circulation

Answer 14

C) Loss of refrigerant

Question 15

A serious reduction in the rate of heat transfer through the condenser surfaces will occur if ________ are permitted to accumulate on the refrigerant-side surfaces of the tubes or coils.
A) Non-condensables
B) Coolants
C) Lubricating oil deposits
D) Refrigerants
E) Refrigerant deposits

Answer 15

C) Lubricating oil deposits

Question 16

A double tube condenser consists of a:
A) Small tube wound around a larger tube
B) Small tube contained concentrically within a larger tube
C) Large tube wound around a smaller tube
D) Large tube contained concentrically within small tube
E) Small tube parallel to a larger tube

Answer 16

B) Small tube contained concentrically within a larger tube

Question 17

The refrigeration condenser must remove __________ absorbed in the evaporator, along with the heat compression added to the refrigerant by the compressor.
A) The sensible heat
B) The latent heat
C) The Enthalpy and entropy
D) Both the latent and sensible heat
E) Both the temperature and pressure

Answer 17

D) Both the latent and sensible heat

Question 18

Trouble may result from the presence of non-condensable gases in the compression refrigeration system:
A) Evaporator
B) Compressor
C) Condenser
D) Regenerator
E) Absorber

Answer 18

C) Condenser

Question 19

The function of the refrigeration condenser is to cool the superheated refrigerant vapour until it _______ and then becomes sub-cooled.
A) Condenses to a vapour
B) Evaporates to a vapour
C) Condenses to a liquid
D) Freezes
E) Evaporates to a liquid

Answer 19

C) Condenses to a liquid

Question 20

One of the main heat exchangers used in the compression refrigeration system is the:
A) Regenerator
B) Evaporator
C) Compressor
D) Cooling tower
E) Absorber

Answer 20

B) Evaporator

Question 21

Defective condenser operation in the compression refrigeration system may result from:
A) Dirty cooling water on the refrigerant side surface of the coils
B) Dirty refrigerant
C) Dirty refrigerant on the cooling surface of the coils
D) Dirty refrigerant on the waterside surface of the coils
E) Dirty cooling water on the waterside surface of the coils

Answer 21

E) Dirty cooling water on the waterside surface of the coils

Question 22

An evaporator is that part of the refrigerating system in which the _______ by the absorption of heat from the medium to be cooled.
A) Vapour refrigerant is condensed
B) Liquid refrigerant is vaporized
C) Vapour refrigerant is vaporized
D) Vapour refrigerant is liquidized
E) Liquid refrigerant is condensed

Answer 22

B) Liquid refrigerant is vaporized

Question 23

One of the basic designs of water-cooled condensers is the _______ condenser.
A) Flooded
B) Bare tube
C) Direct expansion
D) Double tube
E) Evaporative

Answer 23

D) Double tube