Automated deep-freeze warehouses are an important intralogistics issue in food retailing – not only because of the challenging working conditions they create for employees. Efficient deep-freeze intralogistics systems also provide an important contribution to high quality standards. As a pioneer among deep-freeze logistics providers, TGW has been consistently focusing on solutions for deep-freezing: Every system, every component, and every product can be
stored at temperatures of up to -30 degrees Celsius without any problem. In the deep-freeze warehouse, COOP stores deep-frozen products and bakery products from its own production at ambient temperatures between -5° C and -23° C with direct feeding into the pallet warehouse with automatic depalletising or palletising. The Stingray shuttles are at the core of this system.
"TGW is the first company to provide a perfect chill-chain as well as standardised shuttle systems for deep-freeze warehouses."
Michael Schedlbauer, Industry Manager Grocery at TGW
This system configuration allows COOP to operate at the highest possible degree of automation, which is a first important step towards keeping total cost of ownership low. A second, equally important step is creating the right cooling environment for different temperature zones: According to the principle of "store only as cold as necessary", temperatures vary between -2° C and -5° C for depalletising and palletising, and -23° C in the pallet and shuttle warehouses. Also, the oxygen content in the warehouses is inertised to 14 percent by volume for reasons of fire protection.
The process at a glance
- 650 items
- Inbound: 400 pallets per day from external suppliers and 800 pallets from COOP’s own bakery
- Order picking: 55,000 items and 3,500 roller containers per day on average; 100,000 items and 6,000 roller containers on peak days
The pallet warehouse
The -23° C cold pallet warehouse consists of four lanes with over 17,000 storage locations. The pallet warehouse can hold up to two weeks of stock for items needed in the supermarkets. Four storage and retrieval machines, each with two load-handling devices, are used for storing and retrieving goods. The system allows for an output of 135 storage and retrieval operations per hour.
Fully automatic depalletising robots
At -2° C, three fully automatic Splitex depalletising robots handle depalletising, which they do by slightly lifting the individual cartons on one side and then sliding a carrier plate underneath. This ensures that even unstable and non-absorbing cartons are safely destacked and separated. Almost 100% of the pallets are depalletised fully automatically in this way. Only particularly large or poorly packaged products have to be depalletised manually. Depending on the layer pattern, a depalletising robot can handle 1,800 to 2,800 packages per hour, which means that the entire depalletising system with its three robots can process 5,400 to 8,400 packages per hour.
The shuttle warehouse, cooled down to -23° C, consists of seven aisles and 16 levels with more than 40,000 storage locations. The shuttle system is really a highly dynamic picking buffer, as it contains slightly more than one day’s stock. As soon as certain articles fall below minimum stock levels, they are automatically taken from the pallet warehouse and moved to depalletising. Stingray shuttles can store and retrieve up to 4,500 cartons per hour.
When maintenance is due, COOP can easily retrieve shuttles from the aisles and carry out maintenance at a normal temperature.
Fully automatic mixed-carton palletising for frozen products
Manual order picking is particularly difficult at deep-freeze conditions. This is why COOP carefully considered and then opted for fully automatic full case mixed palletising: At -5° C, nine Autostax palletising robots are on the job. The ideal sequence and stacking patterns are pre-calculated automatically, after which the palletising robots are fed the cartons in the correct sequence and process them according to the pre-calculated pattern. Depending on the number of packages, a robot only needs 40 to 130 seconds to load one single roller container. That way, nine robots can fully automatically load 250 to 800 roller containers per hour.