Refrigeration system engineering factors include:
- Year round operation regardless of outdoor ambient (including low temperatures
in winter), wide load functions in short time intervals, i.e., maintaining
total refrigeration availability while the load varies from 0% to 100%,
- Frost control for continuous performance applications,
- Variations in the affinity of oil for refrigerant caused by large temperature changes, and oil migration outside compressor crankcase,
- Choice of cooling medium: (1) direct expansion refrigerant, (2) gravity or
pump recirculated or flooded refrigerant, or (3) secondary coolant (brines such
as salt and glycol)
- System efficiency and maintainability,
- Type of condenser: air, water or evaporatively cooled,
- Compressor design: - open, hermetic, semi-hermetic motor drive;
reciprocating, screw, or rotary,
- System type: single stage, single economized, compound or cascade
arrangement,
- Refrigerant choice: Type of CFC, HCFC, or HFC refrigerant is primarily
selected based upon operating temperature and pressures. While ammonia is the most
common refrigerant for large industrial applications, it is not used for most
commercial refrigeration due to toxicity.
Based on these and related factors, refrigeration engineers select suitable
standard components or custom fabricated components for the particular
application.
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