Deep-freeze storage warehouse built by Unitechnik

The €17m project features automatic high-bay racking with 17,000 pallet locations and is capable of handling up to 2,000 pallets per day. The facility has 6,450m² under-roof floor space, rises to a height of 42m and stores at temperatures down to ‑24 degrees.

The main challenge in designing the distribution hub was fast and smooth process sequences. Consequently, all warehouse and function areas are linked in such a way that paths are as short as possible. This concept was developed by the planning office Metroplan Eastern Europe. Unitechnik was then commissioned with building the logistics facility as general contractor for the racking structure, the conveying system, the automatic cranes and the warehouse control system.

Unitechnik and Knapp customised the work processes specifically to frozen food logistics staff and their application requirements. Following delivery by truck, a worker scans the pallets at the receiving point set up specifically for the load and cooled to -24 degrees. Data is entered in the WMS supplied by Knapp. Depending on the product group, use-by date or batch number, the WMS assigns the pallet a stock location. The WMS also differentiates between refrigerated and deep-freeze sections. In the refrigerated section, the so-called 'chilled area', Macromex primarily stores fresh produce. There are approximately 700 bin locations available in a forklift-managed high-bay racking store. The temperatures in this section are between +2 and +4 degrees. Goods are stored here temporarily, picked to order and packaged. 

Pallets destined for the -24 degree automatic high-bay racking store are directed by Macromex workers onto a conveyor system designed by Unitechnik for these low temperatures. Approximately 250 optical sensors along the path check whether the pallets comply with warehousing requirements. If a pallet does not meet the requirements, the system automatically diverts it. Once a pallet has been reloaded and relabeled, it proceeds to the high bay warehouse. This is the heart of the new logistics hub and at 42m is said to be Europe's tallest automatic deep-freeze storage warehouse. With only three aisles, it still has 17,000 Euro pallet storage locations. Pallets are stored double-deep on 16 levels so that space is optimally used. The storage and retrieval on each aisle is served by a 40.5m high single-mast rail-guided stacker crane from Dambach.

In order to meet fire safety requirements, the high-bay racking store is an inert warehouse, meaning that the oxygen content is 16%. Order picking takes place outside of the system in the order picking and staging area also cooled to -24 degrees. Once a pallet is retrieved, it is automatically brought to this area by the conveyor system. High-speed gates between the high bay warehouse and the order picking area ensure that the different oxygen concentrations are maintained in both areas. Orders are picked using pick-by-voice technology from Vocollect.

Macromex differentiates between fast-moving and slow-moving commodities. A and B articles are picked according to a man-to-goods principle. Via their headsets, pickers are instructed which products are to be taken out in what quantity. The WMS guides them to the corresponding order-picking station along the best path. Macromex stages C articles at a dynamic picking station connected to the conveyor system. Articles are picked according to the goods-to-man principle. Macromex also uses the automatic warehouse to replenish fast-moving areas as well as for full-pallet retrieval.

An important criterion when planning the new distribution hub was maintaining the cold chain. The building is equipped with individual insulating panels 13m long. Inflatable door seals at air locks at shipping and receiving minimise heat exchange and humidity. In addition, truck loading and unloading may take no longer than 27 minutes to preserve the cold chain. Temperatures also place high demands on the technical installations.

Particular attention was placed on the high-bay racking store. To prevent sub-floor freezing, a heated base plate was used as frost heave protection. Due to the temperature fluctuation this causes, the steel structure has to be designed to expand and contract without losing stability. Maintenance staff work in pairs in the High-Bay location. Cameras and walkie-talkies ensure that help is only a push of a button away in an emergency."

Macromex expects business to expand over the next few years and an expansion of the logistics hub that would double capacity is just as feasible as a new "greenfield" building.