By John Ackermann An existing warehouse situated in the Parow Industrial Area, Cape Town, has been converted to an energy efficient Lactalis distribution centre( DC).
INCORPORATING COLD CHAIN
PROJECT
Lactalis’ new high-rise DC cuts energy by 30 %
By John Ackermann An existing warehouse situated in the Parow Industrial Area, Cape Town, has been converted to an energy efficient Lactalis distribution centre( DC).
Lactalis is the largest dairy products group in the world, and is the second largest food products group in France, owning brands such as Parmalat and Président.
The refurbished 14m-high chill cold-store with an ammonia / glycol refrigeration plant boasts eight dispatch / receiving bays to receive and distribute the extensive range of dairy products, cheeses, yoghurts and flavoured milk drinks.
The long-standing relationship between Parmalat and Energy Partners influenced the latter’ s appointment to design the DC with a focus on energy efficiency, productivity, use of natural refrigerants, compliance with SANS10147 and the high safety standards of Lactalis Group. Wherever economic, decommissioned plant and existing equipment on the site were utilised.
The 3.8-hectare site originally featured a refrigerated DC commissioned in 1991, with various additions and replacements made over the years until 2017. Multiple ageing R22 refrigerant plants serviced several cold stores distributed around the site. The existing warehouse was repurposed for the new DC. As with any project in an existing facility, careful planning and design were required to identify and mitigate risks and optimise the new facility within the constraints of the existing infrastructure.
To improve the efficiency and reduce complexity, a single large high-rise warehouse was proposed. The high-bay warehouse was important for energy efficiency, as it reduced the ratio of the exterior surface area to the cold store ' s volume, thereby minimising the amount of energy absorbed through the walls, floor and ceiling. To complement this, polyisocyanurate insulated panels were chosen for their low thermal conductivity and fire resistance properties.
Additionally, insulated docking cubicles with contact cushions were installed to minimise the heat load from ambient air entering the cold room at the dispatch / receiving bays. High-traffic doors leading from ambient areas into the cold room were also installed with automated high-speed insulated doors that reduce the infiltration of hot air.
For the refrigeration system, Energy Partners designed an ammonia refrigeration plant with a propylene glycol secondary refrigerant to provide cooling to the store. A low-temperature circuit was also required for frozen products and a CO2 system was designed to condense on the glycol secondary refrigerant. The combination of ammonia and CO2 met the client’ s
requirement of natural refrigerants.
The ammonia system designed included a gravityfed plate heat exchanger and HP-float without a receiver. This design minimised the ammonia charge. Two evaporative condensers from an old plant were refurbished and used for the system to reduce the capital input required. The condenser fans were installed with variable speed drives to enable floating condensing control and improve the system efficiency.
For the ammonia circuit, two new direct-driven MYCOM piston compressors and an existing belt-driven piston compressor were used. Both new compressors were installed with variable speed drives to enable all operating conditions to be covered, and the belt-driven compressor was used for added redundancy. The combination of the variable speed drives and the piston compressors ensure that all operating conditions are efficiently maintained.
Safety was a high priority for the design; therefore, additional measures were taken to reduce ammonia release from relief valves by installing an absorption tank. A standby stainless-steel tank was installed for this purpose.
Graphics supplied by Energy Partners Graphics supplied by Energy Partners Graphics supplied by Energy Partners
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