Refrigeration Flashcards
Name the 3 types of heat transfer
- Radiation
- Convection
- Conduction
Describe conduction
The transfer of heat between two solid bodies
Eg: Cooking
Describe Convection
Transfer of heat between a solid body & a gas or liquid
Eg:Radiators
Describe Radiation
Energy transfered by electromagnetic radiation
Eg: The sun , Campfire
Heat will always…?
Go from HOT to COLD
Name the 4 on-board refridgeration plants
**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
Increasing pressure increases?
Boiling point
Decreasing pressure decreases?
Boiling point
On a Sight glass indicator Green & Yellow indicate?
Green = Dry
Yellow = Wet
Describe * Natural defrosting*
- Turn off electrics
- Done every 3-6 months
- Air melts the ice
Describe Hot gas defrosting
- Done using hot vapor passed through evaporator
- 1 hour a day 4x15 mins
Defrosting methods
Describe the Electrical heating coils defrosting method
- A wrap around
- Done for 1 hour
What is the Montreal Protocol 1987 about?
CFC gases
What was the Kyoto summit 1997 about?
Limiting greenhouse gases
What is Sensible heat?
The heat required to change temp not the state of a substance
What is Latent heat?
Heat that changes the state of a substance without changing temperature
What is Superheat?
When a substance goes above its boiling point
Name the 5 methods of testing systems for leakage
- Infrared
- Oil slicks
- Spectrodyne
- Snoop
- Halogen detector
What are the 3 oils used in refridgeration?
- OM70 - Gen purpose
- SUNISO - Type 23’s & T-Boats
- SW68- R134A
When you refill your refrigeration oil sump you should..
Use a fresh can of oil,
Refridgeration Oil
What are the 3 methods to adding oil to the sump?
- Sump filler plug
- Hand pump
- Dosing pot
Refridgerant hazard
Chilled water provides cooling for?
- Weapons
- Radar
- Computer systems
- Air treatment unit (ATU)
What gas is produced if refridgerant gets too hot?
Phosgene gas
What is the hazard of fruit and veg stores?
As it rots it produces C02
What are the procedures for entering the refridgeration machinery room?
- Rating in charge informed
- B/A available
- Exhaust fans are on
- No smoking
- Infrared is working
- Warning lights are on
- Have a sentry
- Door can open & close
