Deck 36: Refrigeration Applied to Air Conditioning

Question 1

On a package air-conditioning system, which refrigerant lines must be field-installed?

A) Discharge and suction.
B) Liquid and suction.
C) Discharge and liquid.
D) No lines need to be field-installed.

Answer 1

D

Question 2

The total heat content of infiltrated air of the same dry-bulb temperature may vary from one part of the country to another because of the difference in ____.

A) solar load
B) sensible heat
C) humidity
D) convection currents

Answer 2

humidity

Question 3

In reciprocating compressors used in air conditioning, the motor is mainly cooled by ____.

A) air over the shell of the assembly
B) discharge gas from the compressor
C) suction gas returning to the compressor
D) Both a and c.

Answer 3

D

Question 4

When exposed to salt air, ____ should be used for the screws to secure the sheet metal of cabinets of air conditioning equipment.

A) copper
B) stainless steel
C) iron
D) tin

Question 5

The air temperature of the air off an evaporative cooler is ____.

A) warmer than the entering air
B) cooler than the entering air
C) the same as the entering air
D) made up of sensible heat only

Question 6

A dirty condenser coil can lead to ____.

A) increased efficiency
B) reduced efficiency
C) reduced head pressure
D) increased subcooling

Question 7

If a residential split air-conditioning system has a compressor equipped with a start capacitor and relay, it is probably using a thermostatic expansion valve as a metering device.

Question 8

The moisture content of the air in different locations of the country must be taken into account when selecting air-conditioning equipment.

Question 9

The solar load on a structure is the heat gain resulting from the ____.

A) heat from the surrounding air conducted through the materials of the structure
B) air infiltration
C) heat from the radiation from the sun
D) dry-bulb inside the structure

Question 10

The package air-conditioning system is ____ than the split system because it is completely factory assembled and charged with refrigerant.

A) less efficient
B) slightly less efficient
C) slightly more efficient
D) more efficient

Question 11

The supply duct portion of an air handling system needs to be insulated when run through an unconditioned space.

Question 12

More than one evaporator coil circuit is used when ____.

A) the evaporator is located outside the conditioned area
B) there would be excessive refrigerant pressure drop in the coil circuit
C) a distributor would not be practical
D) a slant coil is at an angle more than 60°

Question 13

Air-conditioning equipment will perform at its best efficiency when running at full load.

Question 14

After being threaded many times, the screw holes in condenser cabinets may become oversized; if so, replace the screws with new ones of the same size.

Question 15

A popular material combination used in air-conditioning evaporators and condensers is ____.

A) copper tube-stainless steel fin
B) copper tube-copper fin
C) copper tube-aluminum fin
D) stainless steel tube-aluminum fin

Question 16

If a structure has no attic, there should be sufficient insulation in the roof to minimize the heat gain in the occupied space.

Question 17

A homeowner plans to build a house out in Las Vegas, Nevada, in the middle of the desert. It would be in his/her best interest to lower the "solar load," to locate most of the windows on the ____ sides of the house.

A) north and east
B) east and west
C) north and south
D) south and west

Question 18

High-efficiency condensers ____.

A) can withstand higher pressures than standard condensers
B) have more surface area than standard condensers
C) have stainless steel coils
D) are located in separate cabinets

Question 19

Appearance is a major drawback with what type of air-conditioning equipment?

A) Ductless split systems.
B) Ground level package units.
C) Rooftop package units.
D) Multi-position package units.

Question 20

In rotary compressors, the motor is cooled by ____.

A) air over the shell of the assembly
B) discharge gas from the compressor
C) suction gas returning to the compressor
D) liquid refrigerant by-passed from the liquid line

Question 21

What is the major advantage a top-air-discharge condensing unit has over a side-air-discharge condensing unit?

Question 22

What is the major disadvantage of a top-air-discharge condenser over a side-air-discharge condenser?

Question 23

Explain some of the disadvantages of the side-air-discharge condensing unit.

Question 24

There are three kinds of attic ventilation: power, natural, and ____________________.

Question 25

What are the three common evaporator designs used on air conditioning equipment?

Question 26

If a high efficiency condensing unit is manufactured with a one-speed condenser fan motor, what is likely to happen if the system is operating during mild weather?

Question 27

When an "A" coil is used in a horizontal application, the coil is laid on its side and a special ____________________ pan is required.

Question 28

Slant coils for downflow application are designed with a coil slant of usually ____________________°.

Question 29

A compressor that uses a stationary vane is the ____________________ type.

Question 30

The return duct portion of an air handling system never needs to be insulated.

Question 31

Three types of expansion devices are used in residential air conditioning systems. They are TXV, capillary tube, and ____________________.