Book 2 Unit 4

Question 1

In the closed cycle compression refrigeration system the compressor not only removes the vapour from the evaporator, but also keeps the pressure in the evaporator at a constant value, which gives the desired __________ temperature of the liquid refrigerant.
A) Expansion
B) Condensation
C) Regeneration
D) Vaporization
E) Cooling

Answer 1

D) Vaporization

Question 2

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

Answer 2

C) High-pressure, high-temperature liquid

Question 3

The boiling point of water is 100ºC (212ºF) when atmospheric pressure is 101.3 kPa (14.7 psi) and is also known as the:
A) Enthalpy
B) Vapour pressure
C) Condensation temperature
D) Vapour temperature
E) Saturation temperature

Answer 3

E) Saturation temperature

Question 4

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 liquidized
B) Vapour refrigerant is Vaporized
C) Liquid refrigerant is condensed
D) Liquid refrigerant is Vaporized
E) Vapour refrigerant is condensed

Answer 4

D) Liquid refrigerant is vaporized

Question 5

A bellows seal consists essentially of a metallic bellows soldered at one end to a ring (seal nose) which bears either against a shoulder on the shaft or against a seal ring mounted on the shaft and the other end is:
A) A sealing ring
B) A mating ring
C) Fastened to a flange which is tightly held against the housing by a cover plate
D) A metallic bellows soldered at one end to the shaft
E) A diaphragm soldered to a seal nose held between compressor body and cover plate

Answer 5

C) Fastened to a flange which is tightly held against the housing by a cover plate

Question 6

The shell and coil condenser consists of a horizontal or vertical steel shell which contains a coiled tube, either bare or finned, through which the _________ circulates.
A) Cooling water
B) Refrigerant vapour
C) Cooling air
D) Condensate
E) Refrigerant liquid

Answer 6

A) Cooling water

Question 7

Based on how they operate one of the basic types of evaporator is the __________ evaporator.
A) Aerial
B) Evaporative
C) Dry/indirect expansion
D) Flooded
E) Cold expansion

Answer 7

D) Flooded

Question 8

The function an air conditioning system that provides a source of moisture to maintain acceptable conditions for human comfort and to minimize the effects of static electricity is:
A) Filtration
B) Ventilation
C) Cooling
D) Heating
E) Humidification

Answer 8

E) Humidification

Question 9

A small residence located in a moderate climate may only require a source of _________ for odour control to maintain acceptable conditions for the occupants.
A) Humidification and ventilation
B) Dehumidification and filtration
C) Heating and cooling
D) Cooling and ventilation
E) Heating and ventilation

Answer 9

E) Heating and ventilation

Question 10

Thermodynamic properties directly affect the movement of heat. Which of these is NOT a thermodynamic property?
A) Enthalpy
B) Density
C) Pressure
D) Volume
E) Leakage tendency

Answer 10

E) Leakage tendency

Question 11

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

Answer 11

A) Small tube contained concentrically within a larger tube

Question 12

The chimney natural draft cooling tower is also known as a ___________ tower.
A) Condenser
B) Hyperbaric
C) Hypergolic
D) Cooling water
E) Hyperbolic

Answer 12

E) Hyperbolic

Question 13

Refrigerants that are non-toxic and non-flammable belong to Group:
A) A1
B) B1
C) A2
D) B2
E) A3

Answer 13

A) A1

Question 14

The sides of atmospheric natural draft towers are ___________ and airflows across the tower by natural currents.
A) Solid
B) Sealed
C) Louvred
D) Lowered
E) Slanted

Answer 14

C) Louvred

Question 15

In terms of energy transformation in the centrifugal compressor the kinetic energy of the ___________ is transformed into potential energy in the high-pressure, low-velocity compressed vapour.
A) High-pressure, high-velocity vapour
B) Low-pressure, high-velocity liquid
C) Low-pressure, low-velocity liquid
D) Low-pressure, low-velocity vapour
E) Low-pressure, high-velocity vapour

Answer 15

B) Low-pressure, high-velocity liquid

Question 16

As a general rule, in the compression refrigeration system the condensing temperature of the vapour will be approximately ____________ higher than the temperature of the water when a water-cooled condenser is used.
A) 20ºC (68ºF) to 25ºC (77ºF)
B) 11ºC (20ºF)
C) 5ºC (41ºF) to 10ºC (50ºF)
D) 0ºC (32ºF) to 5ºC (41ºF)
E) 15ºC (59ºF)

Answer 16

B) 11ºC (20ºF)

Question 17

The heat transfer process that ice undergoes in an ice box is ___________.
A) Latent heat gain
B) Sensible heat gain
C) Sub-cooling
D) Superheating
E) Latent heat loss

Answer 17

A) Latent heat gain

Question 18

Cooling towers are unquestionably the most common type of heat exchanger used when cooling water is scarce, expensive, and a temperature within __________ of the ambient wet bulb temperature is required.
A) 20ºC to 22ºC (68ºF to 72ºF)
B) 15ºC to 17ºC (59ºF to 63ºF)
C) 10ºC to 12ºC (50ºF to 54ºF)
D) 4ºC to 6ºC (8ºF to 12ºF)
E) 27ºC to 29ºC (81ºF to 85ºF)

Answer 18

D) 4ºC to 6ºC (8ºF to 12ºF)

Question 19

The advantages of the Venturi induced draft cooling tower include all of the following except:
A) Its quietness of operation
B) The elimination of fill
C) The absence of any moving parts
D) The elimination of the need for electrical connections
E) It’s quiet fan operation

Answer 19

E) It’s quiet fan operation

Question 20

The applicable code requires that each refrigerating system containing ___________ or more of Group A1 refrigerant having an operating pressure over 103 kPa shall be constructed so the refrigerant can be discharged into the atmosphere by means of a manually operated valve to be used in case of emergency.
A) 182.0 kg (400 lb)
B) 45.0 kg (100 lb)
C) 273.0 kg (600 lb)
D) 91.0 kg (200 lb)
E) 136.0 kg (300 lb)

Answer 20

A) 182.0 kg (400 lb)