PROJECT
INCORPORATING COLD CHAIN
1 2 3
4 6
5 system for the storage of finished product and the manufacturing of dips and meze .
The seafood plant , installed in 2006 , is charged with R404A , which had been a viable refrigerant at the time .
The new CO 2 plant has a trans-critical booster pack with parallel compressors . The pack manufactured in the Ottery workshop of Mainstream Refrigeration has seven Frascold semi-hermetic compressors , all fitted with variable frequency drives ( VFDs ) for capacity control . Three compressors operate on the medium temperature ( MT ) circuit ( -7 ° C ), two on the low temperature circuit ( -32 ° C ), and two provide parallel compression on the MT . The MT circuit maintains the temperature ( 0 – 4 ° C ) in five cold rooms , three double-blast chiller tunnels , and a blast chiller .
The LT circuit has a blast freezer that can also operate as -25 ° C cold room .
The discharge from the MT compressors is piped to a plate heat exchanger fed with water from three air-cooled ( piped in parallel ) finned coolers connected to the municipal water mains . The horizontal coil coolers each have four EC fans , which are speed controlled and / or cycled to maintain required system pressures . Water from the CO 2 plate heat exchanger feeds a 1 000-litre tank as a buffer for a constant supply of water at 40 – 45 ° C to the many hand-washing points , production cookers , and for plant cleaning .
All evaporator coils are direct expansion ( DX ) with copper tubing and aluminium fins and fitted with AC fan motors .
IN-HOUSE SKILLS TRAINING
“ Since doing our first CO 2 plant in 2009 , we have come a long way in the design and installation of CO 2 systems ,” explains
1 . |
The pumps for the cooling water circulation have 100 % backup and are fitted with VFDs . |
2 . |
Hygiene standards are strictly controlled throughout the production area and all staff must |
wash hands and change into boots before entering . |
3 . |
Lourens van Staden ( senior technician ) on left with Richard Drinkrow , MD of Mainstream |
Refrigeration . |
4 . |
Pressure cookers in the production area . |
5 . |
The 1 000-litre make-up tank is connected to the municipal mains . |
6 . |
At the Danfoss ICMTS valve ( grey coloured ), the high-pressure CO 2 gas has a phase |
change to liquid . |
COLD LINK AFRICA • October 2018 |
www . coldlinkafrica . co . za
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