Lesson 4 Flashcards
it is the heart of the refrigeration system. Only a major component that has moving parts
Compressor
Increase pressure by displacing fluid in a shrinking volume.
Positive displacement pressure
High velocity impeller and belongs to turbomachinery class
Centrifugal compressors
Rolling piston and rotary sliding vane
Rotary compressors
Reciprocating ( welded hermetic)
Household refrigerator and freezer
Reciprocating (Open)
Residential and commercial Ac Hp
Rotary vane
Appliances and residential
Rotary scroll
Residential and commercial
Rotary screw
Industrial and commercial
Centrifugal
Industrial and commercial
Welded steel shell houses both compressor and motor
Hermetic
Common, but bolted, housing for compressor and motor. Can be opened and serviced
Semi-hermetic
Motor external shell, largest capacities , shaft seal necessary
Open drive
EER
Energy Efficiency Ratio
SEER
Seasonal Energy Efficiency Ratio
Instantaneous measure of performance
COP
Often expressed as Kw/ton of cooling (or heating)
Compressor power
Depends on compressor type, condenser size and TXV
SEER
Necessary component in all vapor compression systems
Compressor oil
Ability of oil to mix and move with refrigerant
Miscibility
Measure of oil’s flow resistance
Viscosity
Oil must sustain very high electrical voltage
Dielectric strength
Oil’s ability to prevent chemical reactions
Chemical stability
A tendency for refrigeration oils to absorb moisture from the atmosphere
Hygroscopic
A refrigerant compressor operated with an inverter
Inverter Compressor
