Refrigeration System Flashcards
Does refrigeration supply cold air or remove heat?
Refrigeration removes heat from a source
Sensible Heat
Indicated Rise in temperature as heat is added
Latent Heat
No indicated rise in temperature as heat is added
(Heat is being used for phase change)
Radiation Heat Transfer
heat transfer via infared light and some visible lights
Conduction Heat Transfer
Heat transfer from contact between adjacent molecules
Convection Heat Transfer
Heat transfer from motion and mixing portions of a fluid
Define a refrigerant ton
The amount of heat asorbed in melting one ton (2000) LBS of ice in 24 hours
Characteristics of a refrigerant
- boils at low temperature
- could be toxic or flammable (most of these replaced with freon)
- could also cause ozone depletion
How can pressure and temperature affect heat transfer
- Pressure increases then the amount of heat needed is more to raise temperature to a higher boiling point.
Draw a refrigeration cycle
Compressor
Energy Addition
Heat Absorption Heat Rejection
Evaporator Condenser
Expansion valve or metering device
Function of Heat Absorption
Heat transferred source to refrigerant turns it in to a vapor
Function of Energy Addition
Compressor raises pressure and heat to be higher than the cooling medium
Function of Heat Rejection
Heat is transfered via the condenser to a water system and taken away
Function of Expansion
Expansion valve or metering device drops pressure and lowers boiling point of refrigeration to be able to remove heat from source
Function of Evaporator
Transferrs heat from medium to be cooled to low pressure refrigerant
Function of compressors
Adds energy to refrigerant to allow for heat transfer at the condenser
Function of Condensers
Transfers heat from refrigerant to air or water cooling
Function of Receivers
Stores refrigerant in higer capacity systems
Function of Filter/ Drier
Removes particles and debris in systems
Function of liquid line sight glass
Used to show bubbles which could indicate low refrigerant
Function of expansion valves
Throttling device which lowers PSI and Temperature of refrigerant allowing it to remove more heat
Are Refrigerants Flammable?
no
Safety concerns with refrigerants Temperature/ Pressure
Could cause frostbite, heavier than air, line of fire if releasing a cap under pressure
Safety Concerns for refrigerants “Toxic Fumes”
Some fumes are toxic and under extreme temperatures can become Hydrocloric and Hydroflouric Acid. Chill water x area
Safety concerns “Environmental”
Detrimental to wildlife and people
What is a BTU
The amount of heat required to raise 1 lb of water 1 degree
