B Basic Refrigeration Systems

Front 1

Which system is one where the evaporator coil comes into direct contact with the medium to be cooled?

Back 1

A direct system

Front 2

Skating rinks use what as the medium to obtain low temperatures necessary for the ice surface and prevent the secondary refrigerant from freezing. What type of system is this classified as?

Back 2

Brine

Indirect system

Front 3

In an ammonia absorption system the ammonia is heated into a vapor by what type of coil in the generator?

Back 3

Steam

Front 4

In an ammonia absorption system the condenser would change the high pressure vapor into what?

Back 4

A high pressure liquid

Front 5

In an ammonia absorption system, what separates the high side condenser from the low side evaporator?

Back 5

A metering valve

Front 6

Refrigeration engineers are typically associated with what association?

Back 6

ASHRAE

Front 7

Which components of CFCs deplete the ozone layer?

Back 7

Chlorine

Front 8

Which group of refrigerants is considered dangerous and should only be used in industrial applications?

Back 8

A3

Front 9

Too much oil accumulation in which components could cause an oil shortage in the crankcase of the compressor?

Back 9

Evaporator and condenser

Front 10

Which protocol was formed in the mid 80s to ban and limit use of CFCs?

Back 10

Montreal protocol

Front 11

New refrigerants use what type of oil?

Back 11

Polyester

Front 12

A piston type compressor is classified as what?

Back 12

Reciprocating

Front 13

What type of units contain a compressor that is directly coupled to an electric motor, both of which are sealed inside a welded case?

Back 13

Hermetic units

Front 14

What type of compressor will have a shift protruding outside the body, connected to a motor by either a pulley or a direct drive coupling?

Back 14

Open type compressor

Front 15

Evaporator will do what to heat from the medium being cooled? the vapor is then piped where?

Back 15

Absorb heat.

Vapor is piped to the compressor

Front 16

What type of evaporator is widely used in AC applications where the dry or direct expansion method is used?

Back 16

Finned tube type coil

Front 17

Shell and tube type evaporator are reffered to as what?

Back 17

Chillers

Front 18

3 types of Condensers are?

Back 18

Air cooled

Water cooled

Evaporative

Front 19

How do you remove non condensable gases and moisture prior to adding refrigerant?

Back 19

Evacuation

Front 20

Liquid receivers are built to what ASME code?

Back 20

Section 8

Front 21

What refrigerant is most environmentally friendly and human compatable?

Back 21

R 718 (water)

Front 22

Convection currents of liquids and gases are based on what principles?

Back 22

Buoyancy principles

Front 23

The evaporators principle function is to:

Back 23

Absorb heat

Front 24

What code committee decides all refrigerant numbers?

Back 24

ASHRAE

Front 25

What group of refrigerants can be used in industrial applications?

Back 25

All groups

Front 26

The flame on a halide torch will turn green with a small leak of which refrigerant?

Back 26

R 502

Front 27

The pressure/temp relationship between the refrigerant and the evaporator is based on what factors?

Back 27

Size of piping system

Type of refrigerants

Type of refrigeration system

Front 28

Traps and separators are required to do what?

Back 28

Return oil back to the crankcase

Front 29

Which code places refrigerants into 1 of 6 groups?

Back 29

CSA B52

Front 30

What type of system operates on vapor compression/mechanical means?

Back 30

Compression system

Front 31

What type of system operates on non mechanical means?

Back 31

Absorption system

Front 32

What is the function of a compressor?

Back 32

To establish 2 different pressure levels needed for efficient operation

Front 33

What does a liquid metering device do?

Back 33

Regulate the flow of refrigerant into the evaporator

Front 34

In a compression system which 2 components separate the low side and the high side?

Back 34

The compressor and the metering device

Front 35

The refrigeration cycle includes how many pressure changes and how many heat transfer changes?

Back 35

2 pressure changes and 2 heat transfer changes

Front 36

Pressures at and above the condensing pressure of a refrigerant are considered what side?

Back 36

High side

Front 37

Pressures at or below vaporizing pressure of a refrigerant are considered what side?

Back 37

Low side

Front 38

Refrigerants are subjected to 4 different processes. Explain.

Back 38

1. Heat gain evaporator

2. Pressure rise in compressor

3. Heat loss in condenser

4. Pressure loss in metering device

Front 39

True or false. High temperature high pressure gas leaving the compressor is considered to be super heated?

Back 39

True

Front 40

True or false. Low pressure causes refrigerant to Flash inside an evaporator?

Back 40

True

Front 41

What is the main difference between a compression system and an absorption system?

Back 41

Compression system uses compressor absorption system uses absorber, Pump and generator

Front 42

Large AC systems will use this as the absorbent in an absorption system?

Back 42

Lithium bromide

Front 43

How does an absorber work?

Back 43

Refrigerant vapor from the evaporator is drawn into the absorber and mixes with an absorber liquid.

The mix is pumped to a generator where it is heated and the refrigerant is boiled out and leaves the generator as a high temperature high pressure gas

Front 44

What is R - 717?

Back 44

Ammonia

Front 45

What is R - 718?

Back 45

Water

Front 46

A1 refrigerance are mainly what?

Back 46

CFCs

Front 47

What alpha numerical group is group is ammonia classified under?

Back 47

B2

Front 48

What is the most common azeotrope?

Back 48

R502

Front 49

Having an oil separator eliminates the need for this set up on the discharge side of the compressor

Back 49

A double riser

Front 50

What are the 2 purposes of a compressor?

Back 50

1. Create and maintain pressure difference between high and low sides

2. Circulates refrigerant

Front 51

What are the 3 groups of compressors?

Back 51

Reciprocating, Rotary, Centrifugal

Front 52

What are 2 types of evaporators?

Back 52

Dry/direct expansion type and flooded type

Front 53

Which type of evaporator has a higher heat transfer rate?

Back 53

Flooded type

Front 54

What are the 4 construction classifications of evaporators?

Back 54

1. Bare pipe coil

2. Plate type coil

3. Finned tube coil

4. Shell and tube

Front 55

What device is needed if the condenser cannot contain all of the refrigerant needed for the system?

Back 55

Liquid receivers

Front 56

What device is used to protect a small receiver tank? And a large receiver tank?

Back 56

Small = fusible plugs

Large = safety valve