Projects
1
2
This has resulted in the following operating principles being
incorporated in the design:
• Ammonia as a refrigerant.
• Two-stage refrigeration with pumped recirculation for the
highest practical efficiency. A coefficient of performances
(COPs) of 4.4 can be achieved on the compressors.
• Screw compressors with water-cooled oil cooling.
• Variable frequency drive (VFD) for the screw compressors
as well as the reciprocating compressor to ensure close
matching of the operating compressor capacity to the
system heat load.
• VFD for the condenser fans.
• Freezer evaporators mounted in pods for quick effective
defrosting.
• Glycol underfloor heating for the holding freezers.
3
4
REFRIGERATION PLANT DETAILS
The refrigeration plant has a low-stage operating capacity of
875kWR and high-stage operating capacity of 1 410kWR.
There are two low stage duty compressors, one high stage
duty compressor and a swing compressor as standby.
1.
2.
3.
4.
High-stage accumulator vessel.
Glycol and compressor head cooling pumps.
Freezer valve stations and electrical panel.
Receiving and Dispatch coolers and dock levellers.
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RACA Journal I June 2019
43