Industrial refrigeration A Flashcards
refrigerant in screw compressor
propane
liquified overfeed systems in meat packing plants use screw compressor. the refrigerant used
ammonia
heat transfer through physical contact of the molecules to substance
conduction
heat transfer by moving matter
convection
heat transfer by electromagnetic waaves
radiation
matter is packed close together and vibrate slowly
solid
matter with molecules further apart and slide over one another and vibrate faster
liquid
matter with molecules farthest apart they sly away from each other and vibrate quite rapidly
gas
heat cannot be measured with a thermometer
latent heat
heat can be measured with a thermometer
sensible heat
energy that is in motion doing work
kinetic
energy is at rest and is capable of doing work
potential
high pressure side of refrigeration system
compressor, condenser, metering device
low pressure side of refrigeration system
metering device, evaporator, compressor
refrigeration cycle
compress, condense, expand, evaporates
the addition of heat to a vapour, which elevates the temperature higher than the boiling point
superheating
the removal of heat from a superheated vapor
desuperheating
the removal of heat from a saturated liquid
subcooling
absorbs heat from the refrigerated space and serves the overall function of heat transfer, considered the cooling function
evaporator
the device that uses mechanical energy to circulate refrigerant and to maintain a low pressure in the evaporator, while maintaining a high pressure in the condenser
compressor
device that rejects heat from the circuit
condensor
device that throttles and regulates the flow of refrigerant and maintains the pressure difference between the evaporator and the condenser
metering device
the temperature which water can be lowered by evaporating some of the water
wet bulb temperature
what happens to high pressure liquids when pressure is reduced
expands
