Heat Exchangers For Refrigeration Systems

Front 1

The two types of evaporators, dry evaporators and flooded evaporators differ principally in what respect?
a) the dry evaporator cannot cool liquids
b) method of refrigerant circulation
c) type of refrigerant used
d) size of the evaporator
e) field maintenance availability of the types

Back 1

B

Front 2

An evaporator that contains only a small amount of liquid refrigerant at any time is what type of evaporator?
a) Dry evaporator
b) Flooded evaporator
c) Wet evaporator
d) All of the above
e) None of the above

Back 2

A

Front 3

Refrigerant evaporators
a) are only used in ammonia systems
b) are part of the high side of the system
c) are used to transfer oil
d) are only used with very high pressure refrigeration systems
e) are used to transfer heat

Back 3

E

Front 4

The evaporator which increases heat exchange by crimping thin metal plates to its form is which type of evaporator?
a) Plate surface
b) Bare tube
c) Shell and tube
d) Finned tube
e) none of the above

Back 4

D

Front 5

An evaporator which can easily be cleaned and defrosted manually without interrupting the cooling process is which type of evaporator?
a) Bare finned
b) Finned
c) Plate surface
d) Shell and tube
e) None of the above

Back 5

C

Front 6

Which of the following statements about the shell and tube evaporator type is false?
a) It is also known as a chiller.
b) This type of evaporator cools mainly liquids.
c) The refrigerant is circulating in the shell in the flooded operation.
d) Refrigerant vapour is drawn out of the evaporator by the compressor.
e) The liquid to be cooled circulates through the tubes in the direct-expansion operation.

Back 6

E

Front 7

Air-cooled condensers of large capacity are found mainly in which of the following locations?
a) roof tops
b) closed rooms with low air circulation
c) warm dry rooms
d) cold rooms with low air circulation
e) any of the above

Back 7

A

Front 8

Which of the following statements about double tube condensers is true?
a) It consists of two separate tubes side by side.
b) It cannot be used with air cooled condensers.
c) Water flow in the inner tube is in the opposite direction of the flow of refrigerant.
d) It has the highest efficiency of the water-cooled condensers.
e) It is a small condenser for a large capacity system.

Back 8

C

Front 9

The condenser which is very expensive to clean and requires the tubes to be cleaned with acid and neutralized is the
a) shell and tube condenser
b) shell and coil condenser
c) double tube condenser
d) evaporative condensers
e) baffle condensers

Back 9

B

Front 10

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

Back 10

C

Front 11

The common types of water-cooled condensers used in refrigeration systems are: 1. the shell and tube 2. the shell and coil 3. the double tube 4. the plate surface
a) 1, 2, 3
b) 1, 3, 4
c) 2, 3, 4
d) 1, 2, 4
e) 3, 4

Back 11

A

Front 12

Defective condenser operation is a result of the presence of all of the following except
a) scale forming chemicals
b) dirty cooling water
c) noncondensible gases
d) low coolant circulation
e) compressor lubricating oil

Back 12

E

Front 13

The purpose of a condenser in a refrigeration system is
a) to remove the sensible heat from the refrigerant
b) to remove the latent heat from the refrigerant
c) to cool the liquid refrigerant
d) to vaporize the liquid refrigerant
e) to reduce the pressure in the evaporator

Back 13

B