Refrigeration Flashcards
Learn about refrigeration
Explain the pressure/volume relationship
As the volume decreases the pressure increases and as the volume increases the pressure decreases provided that the same amount of gas is present
Explain heat transfer
Heat energy transfers through either conduction, convection or radiation from an area of high heat energy to an area of low heat energy
Explain latent heat
Latent heat is the energy required to change a substances state whilst keeping the temperature the same
Explain sensible heat
The energy required to change a substances temperature whilst the state stays the same
Explain super heat
This is the temperature of a substance above its boiling point
Explain the purpose of a compressor
Compresses the refrigerant into a hot high pressure gas and pushes it around the system
Explain the purpose of the condenser
Changes the state of the hot high pressure gas into a warm liquid by sub cooling it and making sure that all gas is converted to a liquid
Cools the gas with seawater
Explain the purpose of the thermal expansion valve
Controls the flow of the fluid by measuring the pressure out of the evaporator
Allows the fluid to expand making it very cold
Explain the purpose of the evaporator
Uses the now very cold liquid and allows the heat from inside the compartment to heat it up
The heat from the compartment superheated the fluid meaning that there will be no fluid left in the output of the evaporator
What is the purpose of the moisture indicating glass?
To give you an idea of how much moisture there is in the system
What will the moisture indicating glass show?
How much moisture is in the system and it will also show bubbles that have leaked into the system
What is the Montreal Protocol agreement
This is an international agreement to control the amount of substances (CFC, HCFC, Halons) that are released into the atmosphere that destroy ozone
What is the Kyoto Summit agreement?
An international agreement to control the output of CO2, HFC and PFCs into the atmosphere
State 4 methods for leak detection
Oil slicks Snoop Spectrolyne dye and UV lights IRLDS (infra red leak detection system) Halogen leak detector (hand held detector)
State 3 oils used in refrigeration system
OM70
SUNISO 3GS
SW68
What does hygroscopic mean?
It means that it can readily absorb water
What should be used as a source of oil?
A newly opened sealed bottle with the closest volume to what you intend to use otherwise the oil will have time to absorb moisure
What should be done with oil after use?
Collected and disposed of at a shoreside facility.
In accordance with MARPOL and local regulations
How can oil be added to a refrigeration plant?
Sump filler plug
By hand pump
Dosing pot
When will phosgene gas be created?
When exposed to high remperature, refrigerants can be turned into phosgene gas
What gas is given off by fruit and veg when it decomposes?
CO2
What procedures are for entering a refrigeration compartment?
Tell the senior rate that personnel are entering
Breathing apparatus must be available
The high and low exhaust fans are running
No smoking at anytime
The infra red leak detection system must be active and functioning correctly
Trapped personnel light works
Must enter the room in pairs
The internal door opening mechanism must work correctly
What should be done if refrigerant gets in your eyes?
Flush the effected eye(s) with running fresh water and get immediate medical treatment
