Refrigeration/ Air Conditioning Systems

Question 1

what is meant by the term pumping down?

Answer 1

removal of refrigerant before maintenance on a reciprocating system which is to be opened to the atmosphere

Question 2

what is meant by the term pumping when dealing with refrigerant?

Answer 2

to release of air and non condensable gases from a system

Question 3

what is meant by the term slugging?

Answer 3

the liquid refrigerant returning o the compressor causing noisy valves

Question 4

what does the term low side refer to?

Answer 4

the part of system lying between the expansion valve and the suction valve of the compressor

Question 5

the term frosting back refers to what?

Answer 5

the appearance of frost on the suction line extending as far back as the compressor

Question 6

what NSTM would you use when researching refrigeration systems?

Answer 6

NSTM 516

Question 7

what type of refrigeration compressors are used onboard naval ships?

Answer 7

reciprocating and centrifugal

Question 8

the capacity of a reciprocating compressor plant is expressed in?

Answer 8

tons of refrigerant

Question 9

all content high speed compressors operate at what RPM?

Answer 9

1750 rpm

Question 10

what type of lube oil system would be found on a high speed compressor?

Answer 10

force feed lubrication

Question 11

what is the purpose of a thermal expansion valves?

Answer 11

control the quantity of refrigerant that is admitted to the cooling coil and to reduce the pressure of the refrigerant

Question 12

the load on the vapor compression air conditioning plant is determined by what?

Answer 12

the espied chill water temperature

Question 13

two basic types of chilled water air conditioning systems are now in use, they are?

Answer 13

vapor compression and lithium bromide absorption

Question 14

what purpose does the refrigerant compressor receiver serve?

Answer 14

acts as a surge tank and a temporary storage space for the liquid refrigeration

Question 15

where is the dehydrator located in the refrigerant compressor system?

Answer 15

in the liquid refrigerant line between the TXV and the receiver

Question 16

the dehydrator contains what type of drying agent?

Answer 16

silica gel or activated allumina

Question 17

a pink indication on moisture indicator means?

Answer 17

excessive moisture has damaged the indicator, it must be replaced

Question 18

proper refrigerant temperature of a space is maintained by what?

Answer 18

a solenoid valve and its related thermostatic switch

Question 19

what automatically stops a refrigerant compressor when a failure of circulating water supply occurs?

Answer 19

water failure switch

Question 20

the refrigerant liquid strainer is designed to protect what?

Answer 20

the solenoid valves and TXV

Question 21

refrigerant piping is made of what material?

Answer 21

ACR seamless copper

Question 22

nearly all hand operated valves in large refrigeration systems are packless for what reason?

Answer 22

to facilitate maintenance of the valves without valve removal

Question 23

how are refrigerant leaks found?

Answer 23

by use of an electronic leak detector or by the soapsuds test

Question 24

when properly tightened a V-belt can be depressed how far?

Answer 24

1/2 to 3/4 by the pressure of one finger at a point midway between the flywheel and the motor pulleys

Question 25

is it allowable to use belt designs on a V belt?

Answer 25

Never

Question 26

before handling refrigerant bottles you should read what NSTM?

Answer 26

NSTM 670

Question 27

refrigerant cylinders must always be stowed in what manner?

Answer 27

in a cool, dry place, in an upright position

Question 28

never allow a refrigerant cylinder to reach what temperature?

Answer 28

130 deg F

Question 29

cylinder valves must always be protected by what?

Answer 29

cylinder tops

Question 30

what must be done to a refrigerant cylinder when refrigerant has been discharged?

Answer 30

immediately weigh the cylinder and record the weight

Question 31

refrigerants are considered to be deadly due to their composition of what?

Answer 31

halocarbons

Question 32

is it ever allowable to mix refrigerant gases?

Answer 32

never

Question 33

when measuring a certain space temperature, what two temperature readings determine air conditioning effectiveness?

Answer 33

wet bulb and dry bulb thermometer readings

Question 34

dry bulb thermometer is a measurement of what?

Answer 34

sensible heat

Question 35

what approval is required before using self contained air conditioners?

Answer 35

NAVSEA

Question 36

what type of heat exchange is used in the lithium bromide absorption units?

Answer 36

regenerative type

Question 37

what manual contains safety precaution for forces afloat when dealing with refrigerants and air conditioners?

Answer 37

OPNAVINST 5100.19 SERIES

Question 38

what is the latent heat of fushion?

Answer 38

144 BTU’s

Question 39

the most commonly used refrigeration systems used aboard ship is?

Answer 39

vapor compression type with reciprocating compressors

Question 40

what purpose does the compressor in a refrigeration unit serve?

Answer 40

acts a pump

Question 41

heat is absorbed by the refrigeration stored normally in what component?

Answer 41

the refrigerant evaporator

Question 42

the float valves in a centrifugal refrigeration plant serves what purpose?

Answer 42

releases the refrigerant to the chiller