Refrigeration

Question 1

Name the 3 types of heat transfer

Answer 1

1. Radiation
2. Convection
3. Conduction

Question 2

Describe conduction

Answer 2

The transfer of heat between two solid bodies
Eg: Cooking

Question 3

Describe Convection

Answer 3

Transfer of heat between a solid body & a gas or liquid
Eg:Radiators

Question 4

Describe Radiation

Answer 4

Energy transfered by electromagnetic radiation
Eg: The sun , Campfire

Question 5

Heat will always…?

Answer 5

Go from HOT to COLD

Question 6

Name the 4 on-board refridgeration plants

Answer 6

**1. COLD ROOM (Freezer) -18 to -22 degrees
2. COOL ROOM (Fridge) +4 to + 6 degrees
3. FRUIT & VEG STORE +4 to +6
4. GALLEY READY USE CUPBOARD +5 to +7

Question 7

Increasing pressure increases?

Answer 7

Boiling point

Question 8

Decreasing pressure decreases?

Answer 8

Boiling point

Question 9

On a Sight glass indicator Green & Yellow indicate?

Answer 9

Green = Dry
Yellow = Wet

Question 10

Describe * Natural defrosting*

Answer 10

• Turn off electrics
• Done every 3-6 months
• Air melts the ice

Question 11

Describe Hot gas defrosting

Answer 11

• Done using hot vapor passed through evaporator
• 1 hour a day 4x15 mins

Question 12

Defrosting methods

Describe the Electrical heating coils defrosting method

Answer 12

• A wrap around
• Done for 1 hour

Question 13

What is the Montreal Protocol 1987 about?

Answer 13

CFC gases

Question 14

What was the Kyoto summit 1997 about?

Answer 14

Limiting greenhouse gases

Question 15

What is Sensible heat?

Answer 15

The heat required to change temp not the state of a substance

Question 16

What is Latent heat?

Answer 16

Heat that changes the state of a substance without changing temperature

Question 17

What is Superheat?

Answer 17

When a substance goes above its boiling point

Question 18

Name the 5 methods of testing systems for leakage

Answer 18

1. Infrared
2. Oil slicks
3. Spectrodyne
4. Snoop
5. Halogen detector

Question 19

What are the 3 oils used in refridgeration?

Answer 19

1. OM70 - Gen purpose
2. SUNISO - Type 23’s & T-Boats
3. SW68- R134A

Question 20

When you refill your refrigeration oil sump you should..

Answer 20

Use a fresh can of oil,

Question 21

Refridgeration Oil

What are the 3 methods to adding oil to the sump?

Answer 21

1. Sump filler plug
2. Hand pump
3. Dosing pot

Question 22

Refridgerant hazard

Chilled water provides cooling for?

Answer 22

• Weapons
• Radar
• Computer systems
• Air treatment unit (ATU)

Question 23

What gas is produced if refridgerant gets too hot?

Answer 23

Phosgene gas

Question 24

What is the hazard of fruit and veg stores?

Answer 24

As it rots it produces C02

Question 25

What are the procedures for entering the refridgeration machinery room?

Answer 25

1. Rating in charge informed
2. B/A available
3. Exhaust fans are on
4. No smoking
5. Infrared is working
6. Warning lights are on
7. Have a sentry
8. Door can open & close