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Flashcards in Chapter 129 Deck (17)
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1
Q

Atmospheric air may be heated or cooled by installing ______ in the ductwork or in air handling units

A

coils

2
Q

A finned-tube coil may have a heat transfer area from _________ time more than that of bare fare tubes

A

10-30

3
Q

Two types of coils used almost exclusively for heating and cooling services are the:

A

spiral-finned tube, continuous-plate finned tube

4
Q

Coil capacity ______ with the number of fins per unit length of the tube.

A

increases

5
Q

The pressure drop across the coil will determine the:

A

size of the fan motor

6
Q

The greater pressure drop across the coil:

A

the more powerful the fan motor will have to be

7
Q

A characteristics of a double serpentine water coil is:

A

low water pressure drops

8
Q

Which type of coil is designed to produce a high heat capacity with a limited water quantity?

A

half serpentine

9
Q

How can the bond between the fins and tube in a heating coil be improved?

A

solder coating the tubes and fins

10
Q

With counterflow arrangement of air and water the water supply connection is on the same side as the?

A

entering air

11
Q

When the water velocity in the tubes is between 0.3 and 2.4 m/s which water coil is used?

A

single serpentine

12
Q

To obtain full rated capacity of water coils what should be done?

A

connect the water supply for a counterflow arrangement

13
Q

Average velocity of the air flowing over the face area of the fin surface is

A

face velocity

14
Q

The fin surface area of a heating or cooling coil is called:

A

secondary surface area

15
Q

Air venting, in an air conditioning system, is required for adequate:

A

water distribution in the coils and supply/return line

16
Q

The limiting factor for the number of fins that can be used:

A

resistance to airflow

17
Q

A counterflow coil is less efficient than a parallel flow coil (true or false)

A

false