Components
> Compressor: Reciprocating single or two stage compressor is commonly used for compressing and supplying the refrigerant to the system.
> Condenser: Shell and tube type condenser is used to cool down the refrigerant in the system.
> Receiver: The cooled refrigerant is supplied to the receiver, which is also used to drain out the refrigerant from the system for maintenance purposes.
> Drier: The drier connected in the system consists of silica gel to remove any moisture from the refrigerant
> Solenoids: Different solenoid valves are used to control the flow of refrigerant into the hold or room. Master solenoid is provided in the main line and other solenoids are present in all individual cargo holds or rooms.
> Expansion valve: An Expansion valve regulates the refrigerants to maintain the correct hold or room temperature.
> Evaporator unit: The evaporator unit acts as a heat exchanger to cool down the hold or room area by transferring heat to the refrigerant.
> HP and LP cut out: LP cut out is controlled automatically i.e. when the suction pressure drops, the compressor stops and when the suction pressure rises again, the control system starts the compressor. HP or high pressure cut out is provided with manually reset
> Oil Differential Pressure switch compares the measured lubricating oil pressure to the Suction (crankcase) pressure. Should the differential pressure fall below a pre-set minimum (about 1.2 bar) then the compressor will trip and require a manual reset to restart. A time delay is built into the circuit to allow sufficient time for the lubricating oil pressure to build up when starting before arming the circuit.