Refrigeration Principles Flashcards
What are the components of a basic compressor?
Evaporator
Compressor
Condenser
Expansion valve
What do you need for efficient compression plant operation?
Evaporation temp high was possible
Condensation temp low as possible
Delta T a small/low as possible
What are some characteristics of the ideal coolant agent?
Non toxic
Non corrosive
Low viscosity
High specific evaporation
High volumetric refrigerating capacity
High heat conductance
What are 2 advantages of direct cooling system?
Low electric consumption
High operation pressures in heat transfers
What are 2 disadvantages to indirect cooling systems?
High electricity consumption
High investment in insulation
Why is ammonia commonly used as a primary refrigerant?
Easy Neutralisation
Not mixable with lubricants
Long history of use
Great thermodynamic properties
Strong Odor (good for leak detection)
What are 2 primary refrigerants?
Ammonia
Carbon dioxide
What are 3 secondary refrigerants?
Brines
Alcohol water (glycol)
Ice water
What are 3 types of compressors?
Piston, worm, turbo
What are some characteristics of piston compressors?
Step operation
Single and mutlicylinder
Single or double acting
25-7,500 kWh per hour needed to rub
What are some advantages of a centralized plant?
Common condenser
Cooling output may be regulated in steps
Spare parts management is easier
Compressors of coming design in one power house
What are some disadvantages of decentralized refrigeration plants?
Difficult spare parts management
Specific plant expenses higher
A second reserve chiller usually necessary
Not every compressor type practical
What is the driving mechanism for an adsorption refrigeration plant?
Thermal drive (absorbing and releasing in a chemical nature instead of mechanical)
What is the function of the compressor?
Increases temperature, pressure, moves coolant
What is the definition of primary refrigerant?
It changes its state - the thing that’s doing all the work
By changing state heat will be absorbed or released
