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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