Deck 21: The Cooling System

Question 1

The tremendous popularity of mechanical refrigeration for household use in the 1930s and 1940s stimulated the development of a new series of nonexplosive and nontoxic refrigerants known as of the halogen family.

A)chlorinated hydrofluorides
B)chlorofluorocarbons
C)PCBs
D)dioxins

Answer 1

A

Question 2

The system for the drugstore and bakery is a system with the compressor and condenser located on the ground adjacent to the building and the evaporator located in an air-handling unit in the basement.

A)joint
B)split
C)unified
D)dual

Answer 2

B

Question 3

compressors are usually used in large installations.

A)Helical
B)Direct-drive
C)Hermetically sealed
D)Fin tube

Answer 3

B

Question 4

The component of the refrigerant cycle raises the energy level of the refrigerant so that it can be condensed readily to a liquid.

A)evaporator
B)compressor
C)condenser
D)expansion valve

Question 5

Where was the initial demand for hermetic compressors and what were the implications of this?

Question 6

The compressor serves as a pump to draw the expanded refrigerant gas from the evaporator, boosts the of the gas, and sends it to the condenser.

A)temperature
B)volatility
C)pressure
D)stability

Question 7

Overload protection of the internal components is covered in the Standards.

A)ICEA
B)NFPA
C)TUV
D)UL

Question 8

The evaporator in a commercial installation normally consists of a coil, through which the building air is circulated by a motor-driven fan.

A)plate tube
B)helical tube
C)fin tube
D)fan plate

Question 9

A motor-compressor must be protected from overloads and failure to start by a time-delay fuse or inverse-time circuit breaker rated at not more than percent of the rated load current.

A)95
B)105
C)115
D)125

Question 10

When is the branch-circuit selection current marked?

Question 11

Air-conditioning and refrigeration equipment is required by NEC 440.4(A) and (B) to be marked with a marked with the maker's name, the rating in volts, frequency and number of phases, and other information.

A)removable label
B)3 in.x 5 in.nameplate
C)set of labels
D)visible nameplate

Question 12

What does NEC 440.14 require of the disconnecting means in terms of location, access, installation, and mount?

Question 13

The hermetic compressor consists of a motor-compressor completely sealed in a gastight, casing.

A)aluminum
B)cast iron
C)steel
D)plastic

Question 14

____ is a method of removing energy in the form of heat from an object.

A)Conduction
B)Convection
C)Radiation
D)Refrigeration

Question 15

The disconnecting means for an individual hermetic motor-compressor must not be less than percent of the rated load current or the branch-circuit selection current, whichever is greater.

A)95
B)105
C)115
D)125

Question 16

NEC 110.9 states that equipment intended to interrupt current at levels shall have an interrupting rating sufficient for the nominal circuit voltage and the current that is available at the line terminals of the equipment.

A)fault
B)maximum
C)minimum
D)average

Question 17

In most instances, the RLA is at least equal to percent of the hermetic refrigerant motor­compressor's maximum continuous current (MCC).

A)16.1
B)32.1
C)64.1
D)96.1

Question 18

Can you cool your kitchen by leaving the refrigerator open? Explain why or why not.

Question 19

Where is the expansion valve located, and how does it function?

Question 20

Air-cooled condensers use to drive air across the condensing coil.

A)ambient evaporation
B)a motor-driven fan
C)a pump
D)a temperature-difference fan