Refridgeration

Question 1

The low side of a vapor compression cycle contains the?

Answer 1

Evaporator

Question 2

What is the primary unit of heat used in the United States

Answer 2

BTU British thermal unit

Question 3

Which direction does heat flow

Answer 3

From warm to cold

Question 4

In which component does refrigerant release or exhaust heat

Answer 4

The condenser

Question 5

Besides temperature what other fundamental variable can be changed to alter the boiling point of a substance

Answer 5

Pressure

Question 6

Where is the atmospheric pressure greater Miami or Leadville

Answer 6

Miami

Question 7

Besides conduction and convention what is another method heat is transferred from one substance to another

Answer 7

Radiation

Question 8

What causes atmospheric pressure

Answer 8

The pressure or mass of the atmosphere pushing down on the earths surface

Question 9

Refrigeration cycles move heat from one location to another using what type of heat

Answer 9

Latent heat transfer

Question 10

When a refrigeration system moves heat does it release more less or the same amount of heat that it absorbs

Answer 10

More

Question 11

Which term refers to liquid refrigerant super heated or sub cooling

Answer 11

Sub cooling

Question 12

Is the refrigeration cycle that operates in the water fountain the seam is that in a large chiller

Answer 12

Yes

Question 13

What best identifies the nature of refrigerant going in and out of the metering device

Answer 13

Liquid in gas liquid mix out

Question 14

In normal operation does liquid refrigerant return to the compressor in the refrigerating machine

Answer 14

No

Question 15

How many thousand BTU per hour generate a ton of cooling capacity

Answer 15

12,000 BTU per hour

Question 16

What best identifies the nature of the refrigerant going in and out of the condenser

Answer 16

Gas in liquid out

Question 17

Compressors add heat to the refrigerant in two ways what are they

Answer 17

Heat of compression and motor heat

Question 18

Gaseous refrigerant heated above its boiling point is said to be

Answer 18

Super heated

Question 19

What is the word used to describe the state of matter of gas heated just a little above its boiling point

Answer 19

Superheated

Question 20

True or false most of the heat transferred by the refrigerant in a vapor compression cycle is a latent heat

Answer 20

True

Question 21

Sub cooling occurs in which of the four parts of the refrigeration cycle

Answer 21

Condenser

Question 22

Which has more enthalpy a pound of water at 32° or a pound of ice at 32°

Answer 22

A pound of water

Question 23

What unit is enthalpy expressed in

Answer 23

Btu/lb

Question 24

What are the primary hazards when working around refrigerant in an enclosed area

Answer 24

Suffocation and displacement of oxygen

Question 25

Refrigerant recovery cylinders are equipped with which safety devices

Answer 25

Fusible plug and pressure relief valve

Question 26

What gas is used to purge refrigerant lines during brazing

Answer 26

Nitrogen

Question 27

What direction is refrigerant piping sloped

Answer 27

It is slightly sloped down in the direction of refrigerant flow

Question 28

What piping configuration keeps oil or liquid refrigerant from running back down the discharge line in the office cycle

Answer 28

S or inverted trap

Question 29

What type of fitting is not acceptable for copper refrigerant lines

Answer 29

Compression fittings

Question 30

If the temperature of a full refrigerant recovery cylinder is increased what happens to the pressure inside the cylinder

Answer 30

The pressure will rise

Question 31

Scientists have identified CFC &HCFC refrigerants as agents of __________Depletion in the upper atmosphere

Answer 31

Ozone

Question 32

A condensing unit contains which two of the four main refrigeration components

Answer 32

Condenser and compressor

Question 33

How does a suction or discharge line P-trap assist with the flow of oil

Answer 33

It builds up a pool of oil which partially blocks the pipe reducing the effective size of the pipe and causing oil to entrain with the refrigerant

Question 34

In which state does oil Best mix with refrigerant

Answer 34

Liquid

Question 35

Are liquid line solenoid valves directional, that is does it matter which side you connect the liquid line from the condenser and which side points to the metering device

Answer 35

Yes

Question 36

Brazing rod comes in the 0% 5% 15% in some higher percentages like 40% what metal is referred by the percentages

Answer 36

Silver

Question 37

What brazing rod requires a special paste flux when making copper to steel joints

Answer 37

40%

Question 38

When a flame is exposed to refrigerant gas what is produced

Answer 38

Acids

Question 39

What two forces act on oil movement in refrigeration systems

Answer 39

Gravity and refrigerant velocity

Question 40

What is an undesirable side effects of an undersized pipe in refrigerant piping

Answer 40

Too high of a velocity

Question 41

What is an undesirable affect of an oversize pipe in refrigerant piping

Answer 41

Too low of velocity allowing refrigerant and oil to separate

Question 42

What device is installed to prevent refrigerant migration to the evaporator in the off cycle

Answer 42

Liquid line solenoid valve

Question 43

What weight of tubing is commonly used in refrigeration installations

Answer 43

Type L

Question 44

What is cleaned out of copper tubing labeled ARC/OXY or med gas that is left in regular tubing

Answer 44

Manufacturing oils and waxes

Question 45

What can help fit up larger copper refrigeration fittings

Answer 45

Paraffin wax or soap

Question 46

One practice that helps larger tubing fittings fit up is

Answer 46

File away the lip on the outside of the pipe left over from the tubing cutters

Question 47

What is the purpose of pressurizing ARC tubing with dry nitrogen for shipping and storage

Answer 47

To keep oxygen out preventing oxidation

Question 48

Removing banks of pistons from operation to achieve a reduction in compressor capacity is a feature of which type of compressor

Answer 48

Reciprocating

Question 49

True or false compressors with unloaders are typically set up to start fully loaded

Answer 49

False

Question 50

If the compressor is fully unloaded and compressor operation still results in suction gas pressure below desired levels what is accessory may be installed to address the situation

Answer 50

Hot gas bypass

Question 51

What is the order of the state of refrigerant as it passes through the condenser in normal operation

Answer 51

Gas to saturated vapor to sub cool the liquid

Question 52

What can cause higher compressor head pressure's

Answer 52

Debris in bedded in condenser coil's or build up of dust on condenser coil's

Question 53

The amount of heat rejected in the condenser is greater than or less than the amount of heat absorbed in the evaporator

Answer 53

Greater than

Question 54

What flower arrangement results in the most efficient heat transfer three hydronic heat exchanger or coil

Answer 54

Counter flow

Question 55

Excessively high temperature difference between the entering and leaving water of a condenser could indicate

Answer 55

Restricted water flow

Question 56

What type of condenser is typically found on smaller equipment

Answer 56

Double pipe

Question 57

What type of water condenser is typically found on larger equipment

Answer 57

Shell and tube

Question 58

What measure is taken to reduce the buildup of scale in cooling tower water loops

Answer 58

Chemical additive

Question 59

If a chilled water source is used to remove heat from the water cooled condenser what device might be installed to keep head pressure steady

Answer 59

Water regulating valve

Question 60

A once through water cooled condenser refers to an application which

Answer 60

City water passes through the condenser and then down the drain

Question 61

To keep condenser water from getting too cold contemporary cooling towers typically use what for leaving water temperature control

Answer 61

A variable frequency drive on the fan motor to modulate fan speed

Question 62

What measurement is taken to keep cooling tower sumps from freezing in the winter

Answer 62

Heat trace or receiving tank on the inside of the building

Question 63

Water levels in the sump of a cooling tower or the evaporative condenser are typically controlled by what

Answer 63

A float valve

Question 64

What advantages do water cooled condenser's have over air cooled condenser's

Answer 64

Lower condensing temperatures and pressure on the refrigerant side making compressor is more efficient

Question 65

What are the advantages of air cooled condensers over cooling tower systems

Answer 65

No seasonal changes in operation are needed

Question 66

The main problem with the air cooled condensers in some areas of the country like ours is

Answer 66

Cottonwood debris that blows through the air gets sucked into them