Refrigeration

Question 1

As pressure increases

Answer 1

Volume decreases and more energy is required to boil a liquid.

Question 2

As pressure decreases

Answer 2

Volume increases and less energy is required to boil a liquid.

Question 3

3 types of Heat transfer?

Answer 3

Conduction
Convection
Radiation

Question 4

Describe Conduction?

Answer 4

Heat transfer through a solid

Question 5

Describe convection?

Answer 5

Heat transfer through a fluid.

Question 6

Describe Radiation?

Answer 6

Heat transfer through a space.

Question 7

Describe sensible heat?

Answer 7

Heat required to change temp not change state of substance.

Question 8

Describe latent heat?

Answer 8

Heat required to change state of substance not the temp.

Question 9

Describe superheat?

Answer 9

Substance goes above boiling point it is superheated. Every degree in heat gains 1 point degree of superheat.

Question 10

Describe sub-cooling?

Answer 10

Substance cools and condenses into liquid then drops below its boiling point.

Question 11

4part refrigeration components?

Answer 11

Compressor
Condenser
Thermal expansion valve (TEV)
Evaporator

Question 12

Function of compressor?

Answer 12

Pumps refrigerant around the system.

Question 13

Function of condenser?

Answer 13

Used sea water too cool the refrigerant changing its state from a gas into a liquid.

Question 14

Function of a (TEV)?

Answer 14

Controls flow rate of refrigerant through a system increase and decrease flow depending on temp of refrigerant leaving evaporator.

Question 15

Function of evaporator?

Answer 15

Refrigerant flowing through evaporator removes heat from refrigerator changes state from liquid to gas.

Question 16

LP cut out?

Answer 16

Stops compressor if pressure drops.

Question 17

HP cut out?

Answer 17

Stops compressor if pressure gets too high.

Question 18

Oil separator?

Answer 18

Separates oil from the refrigerant.

Question 19

Liquid receiver?

Answer 19

Stores refrigerant during maintenance.

Question 20

Function of Drier?

Answer 20

Removes moisture from refrigerant.

Question 21

Sight glass?

Answer 21

Indicates moisture in the refrigerant
Yellow - there is moisture
Green - there isn’t moisture

Question 22

Methods of defrosting?

Answer 22

Natural defrost- every 3 to 6 months
Hot gas defrost- maximum of 1 hour in 15 minute slots.
Electric heating coils- same as hot gas.

Question 23

Methods of leak detection?

Answer 23

Oil slicks 
Infra-red leak detection system
Spectrolyne dye and UV lamp
Snoop
Halogen leak detector

Question 24

3 lubricants?

Answer 24

OM70
SW68
Suniso 3GS

Question 25

Ways oil is added to the compressor?

Answer 25

Via sump filler plug
By a hand pump
Through the use of a dosing pot

Question 26

Montreal protocol?

Answer 26

CFC
HCFC
HALONS

Question 27

Kyoto summit - reduce greenhouse gasses.

Greenhouse gasses?

Answer 27

CO2
HFC
PFC

Question 28

What is chilled water used for?

Answer 28

Weapon systems
Radars
Ships computer systems
Air treatment units (ATU)