Industrial Refrigeration

Question 1

What is the vapour compression system of refrigeration?

Answer 1

compressor ➡️ condenser ➡️ metering device ➡️ evaporator

Question 2

what are five hazards that exist when working with refrigeration systems?

Answer 2

high pressures
toxic gases
burns
freezing of flesh
electrical shock

Question 3

True or False:

heat travels from hot to cold?

Answer 3

true

Question 4

what is conduction?

Answer 4

heat transfer by physical contact

Question 5

what is convection?

Answer 5

heat transfer by moving matter

Question 6

what is radiation?

Answer 6

transfer of heat by electromagnetic waves

Question 7

refrigeration is the process of moving ____________?

Answer 7

heat

Question 8

what is sensible heat?

Answer 8

heat that can be measured with a thermometer.

Question 9

what is latent heat?

Answer 9

heat that is added or removed to change state.

Question 10

what are two ways to make a liquid boil?

Answer 10

add heat
lower the pressure

Question 11

what are the four main components in the vapour compression refrigeration cycle?

Answer 11

compressor
condenser
metering device
evaporator

Question 12

where is the heat from the surroundings added to the refrigeration?

Answer 12

in the evaporator

Question 13

what is meant by the high side and the low side in the refrigeration cycle?

Answer 13

high pressure side and low pressure side

Question 14

what is a hermetically sealed unit?

Answer 14

unit that is completely sealed from the atmosphere

Question 15

why is nitrogen used when the refrigeration piping is welded?

Answer 15

so the inside of the pipe is kept as clean as possible from oxidization

Question 16

what two things circulate through the refrigeration piping?

Answer 16

refrigerant
oil

Question 17

the boiling temperature of a liquid and the condensing temperature of a vapour can be the same as long as the _____________ exerted on the fluid is the same

Answer 17

pressure

Question 18

as it changes into a vapour, a liquid absorbs the _______________________

Answer 18

latent heat of vaporization

Question 19

as it condenses into a liquid, a vapour rejects the _________________

Answer 19

latent heat of condensation

Question 20

what should the first response be if a worker is splashed with liquid ammonia?

Answer 20

safety shower

Question 21

on a flooded system, the brine tubes are immersed in the liquid _________________

Answer 21

refrigerant

Question 22

all ammonia-flooded systems require an oil separator because the __________ does not return to the compressor.

Answer 22

oil

Question 23

the liquid levels in liquid overfeed low-pressure receivers are monitored and controlled by_______________

Answer 23

float switches

Question 24

lithium bromide (absorption) refrigeration uses ____________ energy to produce the refrigeration effect

Answer 24

heat

Question 25

____________ is used as the refrigerant in the lithium bromide absorption system.

Answer 25

water

Question 26

in the absorber, the solution becomes ____________ as it absorbs water vapour.

Answer 26

diluted

Question 27

the concentrator drives the water vapour out of the lithium bromide solution by adding ___________ to the solution

Answer 27

heat

Question 28

in an absorption system, the heat exchanger serves a vital function, it _________ the dilute solution and __________ the concentrated solution

Answer 28

heats
cools

Question 29

cooling the concentrated solution too fast can cause _____________

Answer 29

crystallization

Question 30

in order to shut down the absorption chiller safely, the system must run through the _____________ cycle to prevent crystallization

Answer 30

dilution

Question 31

what are three common maintenance checks performed on condensers and evaporators?

Answer 31

leaks
fouling or plugging
piping connections

Question 32

____________ analysis and treatment can prevent scale and algae build up in cooling towers

Answer 32

water

Question 33

when performing an alignment on a refrigeration compressor and electric motor, you must account for ____________________

Answer 33

thermal growth

Question 34

what five tools can assist you when performing maintenance checks on a compression refrigeration system?

Answer 34

thermometer
multimeter
pressure gauge
leak testing device
manual

Question 35

the metering device on a compression refrigeration system can be a ____________, _______________ or a _____________

Answer 35

capillary tube
fixed orifice
thermostatically controlled expansion valve

Question 36

what 3 symptoms indicate that the system is low on refrigerant?

Answer 36

inability to cool
iced up evaporator coil
warm air flow from ventilation ducting

Question 37

name three methods of heat transfer

Answer 37

conduction
convection
radiation

Question 38

what happens in the evaporator?

Answer 38

heat is taken in
liquid is evaporated into a gas

Question 39

what happens in the condenser?

Answer 39

heat is rejected
gas is condensed into a liquid

Question 40

what happens when we increase the pressure on a fluid being heated?

Answer 40

raise the boiling point

Question 41

where is the lithium bromide concentration increased?

Answer 41

in the generator

Question 42

what two units in the absorption system require cooling water?

Answer 42

absorber
condenser

Question 43

what happens if the Li-Br solution becomes too concentrated?

Answer 43

it crystallizes

Question 44

what is the dilution cycle used for?

Answer 44

slows down the cooling process so the lithium bromide does not crystallize

Question 45

what unit is steam or hot water used in?

Answer 45

generator

Question 46

what units consist of the low pressure system?

Answer 46

evaporator, condenser, metering device

Question 47

where is the metering device located?

Answer 47

between the low and high pressure side

Question 48

which has the higher boiling point? Water or Li-Br?

Answer 48

water