Book 2: 4-21 - "Cooling Towers"

Question 1

The chimney natural draft cooling tower is also known as a _____ tower.
Select one:

A. Hypergolic

B. Condenser

C. Hyperbolic

D. Cooling water

E. Hyperbaric

Answer 1

C. Hyperbolic

Question 2

The water to be cooled is distributed in the tower by spray nozzles and splash bars to expose a very _____ surface area to atmospheric air thus aiding evaporation.
Select one:

A. Large air

B. Large water

C. Small air

D. Small water

E. Wet water

Answer 2

B. Large water

Question 3

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.
Select one:

A. 15°C to 17°C (59°F to 63°F)

B. 27°C to 29°C (81°F to 85°F)

C. 4°C to 6°C (8°F to 12°F)

D. 20°C to 22°C (68°F to 72°F)

E. 10°C to 12°C (50°F to 54°F)

Answer 3

C. 4°C to 6°C (8°F to 12°F)

Question 4

The induced draft cooling tower has one or more fans located at the top of the tower that _____ the downward flow of water.
Select one:

A. Draw air upwards against

B. Draw air upwards with

C. Draw water upwards against

D. Draw water upwards with

E. Draw air downwards against

Answer 4

A. Draw air upwards against

Question 5

The rate of heat transfer in any cooling tower system depends on all the following except the:
Select one:

A. Area of water surface in contact with the air

B. Relative velocity of both air and water during contact

C. Difference between the inlet water temperature and the inlet air wet bulb temperature

D. Length of contact time between the air and water

E. Atmospheric pressure

Answer 5

E. Atmospheric pressure

Question 6

A cooling tower is a device that uses a combination of heat and mass transfer to lower the temperature of the:
Select one:

A. Refrigerant

B. Chilled water

C. Cooling water

D. Condenser

E. Condensate

Answer 6

C. Cooling water

Question 7

During cold weather operation what water basin temperature is required prior to allowing full water flow over the cooling tower fill?
Select one:

A. 20°C (68°F)

B. 32°C (90°F)

C. 27°C (81°F)

D. 10°C (50°F)

E. 15°C (59°F)

Answer 7

C. 27°C (81°F)

Question 8

The fans at the top of the induced draft cooling tower discharge the _____ upward and away from the air entering at the bottom of the tower.
Select one:

A. Hot, moisture-laden air

B. Cool, moisture-laden air

C. Hot, dry air

D. Cool, moisture-laden water

E. Hot, moisture-laden water

Answer 8

A. Hot, moisture-laden air

Question 9

One of the advantages of the crossflow mechanical draft tower over the counterflow tower is the _____ leading to lower energy costs.
Select one:

A. No fan requirement

B. Higher fan power requirement

C. Lower temperature requirement

D. Lower fan power requirement

E. Higher temperature requirement

Answer 9

D. Lower fan power requirement

Question 10

Atmospheric natural draft towers are used in areas that have _____.
Select one:

A. Low winds and little water

B. Relatively constant winds and large open spaces

C. No need for a large cooling water supply and return temperature differential

D. Economical supply of electricity

E. An economical supply of cooling water

Answer 10

B. Relatively constant winds and large open spaces

Question 11

The sides of atmospheric natural draft towers are _____ and airflows across the tower by natural currents.
Select one:

A. Sealed

B. Louvred

C. Lowered

D. Slanted

E. Solid

Answer 11

B. Louvred

Question 12

The counterflow mechanical draft tower occupies less floor space than a crossflow tower but is _____ for a given capacity.
Select one:

A. Taller

B. Smaller

C. Faster

D. Shorter

E. Larger

Answer 12

A. Taller

Question 13

During the operation of a forced draft cooling tower, which of these is NOT true?
Select one:

A. A fan forces air at a low velocity through the packing

B. Water entrained in the air is removed by the drift eliminators

C. Vibration and noise are at a maximum

D. The fans handle mostly dry air

E. Water flows downward

Answer 13

C. Vibration and noise are at a maximum

Question 14

The basic components of a cooling tower include all of the following except:
Select one:

A. Cooling water circulating pumps

B. Inlet air louvres

C. Drift eliminators

D. Air moving equipment

E. Cooled water basin

Answer 14

A. Cooling water circulating pumps

Question 15

Possible operational problems with natural draft cooling towers may include all of the following except:
Select one:

A. Excessive water drift

B. Reduction in water flow

C. High discharge water temperature from the tower

D. Low discharge water temperature from the tower

E. Tower basin or sump overflowing

Answer 15

D. Low discharge water temperature from the tower

Question 16

A monthly inspection of a natural draft cooling tower should include all of the following except:
Select one:

A. Cleaning the suction screen

B. Cleaning the louvres, piping, and nozzles

C. Cleaning the water basin and checking for leaks

D. Checking the atmospheric wet bulb temperature

E. Checking that the float control valve is operating properly

Answer 16

D. Checking the atmospheric wet bulb temperature

Question 17

The actual transfer of heat in a cooling tower is accomplished by a sensible heat transfer (heating the air passing through the tower), and by the removal of latent heat as a result of the evaporation of about _____ of the water.
Select one:

A. 8%

B. 10%

C. 15%

D. 5%

E. 2%

Answer 17

D. 5%

Question 18

The advantages of the venturi induced draft cooling tower include all of the following except:
Select one:

A. The elimination of fill

B. Its quietness of operation

C. The elimination of the need for electrical connections

D. Its quiet fan operation

E. The absence of any moving parts

Answer 18

D. Its quiet fan operation

Question 19

One of the advantages of the crossflow mechanical draft tower over the counterflow tower is the:
Select one:

A. High pressure drop in relation to its volume

B. Low temperature drop in relation to its capacity

C. Low pressure drop in relation to its capacity

D. Low pressure drop in relation to its volume

E. High pressure drop in relation to its capacity

Answer 19

C. Low pressure drop in relation to its capacity

Question 20

Excessive water drift due to faulty drift eliminators in a cooling water tower may be caused by all except:
Select one:

A. There must be no leaks under hot water basin sides

B. Eliminator sections, or slats and splash retainers out of place

C. Fill packs intact and in place with no sagging or gaps

D. Top deck assemblies and wood till splash bars intact and level

E. Metering orifices in place and clean of debris

Answer 20

D. Top deck assemblies and wood till splash bars intact and level