There are several mechanical components required in a refrigeration system. In this part, we discuss the four major components of a system and some auxiliary equipment associated with these major components. These components include condensers, evaporators, compressors, refrigerant lines and piping, refrigerant capacity controls, receivers, and accumulators,
Major components of a vapor-compression refrigeration system are as follows:
• evaporator, and
• throttling device.
In the selection of any component for a refrigeration system, there are a number factors that need to be considered carefully, including:
• 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 the compressor crankcase,
• selection of cooling medium: (i) direct expansion refrigerant, (ii) gravity or pump recirculated or flooded refrigerant, or (iii) secondary coolant (brines, e.g. salt and glycol),
• system efficiency and maintainability,
• type of condenser: air, water or evaporatively cooled,
• compressor design (open, hermetic, semihermetic motor drive, reciprocating, screw or rotary),
• system type (single stage, single economized, compound or cascade arrangement),
• selection of refrigerant (note that the type of refrigerant is basically chosen based on operating temperature and pressures).