By Bob Jane, Sales Manager Dynamics Systems, SSI Schaefer.
In freezer warehousing, the primary cause of lift truck equipment failure is condensation caused by the constant in-and-out movement of product by lift trucks operating between -28 degrees c and ambient air temperature within loading docks. Extreme temperature swings cause moisture to form, resulting in the failure of electronics, electro-mechanical components and wiring.
The only solution preventing condensation in freezer warehousing is by keeping lift trucks inside the freezer which has seen the result in the design and use of fork lift trucks with heated cabs. These lift trucks never leave the freezer warehouse, allowing operators to be both warm and productive during an entire shift.
So, if fork lift trucks never leave the cold store, how are pallets stored, picked and shipped? The answer is pallet conveyor technology with in-bound and out-bound spurs. Whether unloading a trailer or moving pallets from a production area into a freezer warehouse, pallets can be placed onto a conveyor outside the freezer entering via high-speed compartment doors – the doors are then sealed quickly to minimise warmer exterior air entering the cold store.
Today’s freezer warehouses typically use large ‘barn-size’ doors equipped with plastic strip curtains to reduce cross-contamination of warm air entering the freezer. However, the constant movement of lift trucks actually creates the opposite result – heat and temperature variation – it is much more expensive to cool air than it is to heat air.
Two choices – automating freezer warehouses and keeping lift trucks inside the freezer can reduce energy consumption by as much as 80%, and reduce labour costs by as much as 70%.
Once the pallets enter the freezer warehouse they travel on conveyor to the pick-up point. The lift truck then picks the pallet at the end of the conveyor line for put-away, resulting in reduced travel time due to much shorter distances between pick-up and storage locations.
Using conveyor technology also results in considerably lower labour costs because the same throughput can be accomplished with fewer operators. And, lift truck wear-and-tear is significantly reduced by shorter travel distances. Outbound picking – in which pallets are placed on an outbound conveyor – also results in much shorter travel distances, less lift truck use, less wasted time: lower costs.
The other component of a better cold store design is better storage technology, more specifically a high-density storage system. A typical cold store utilises selective pallet racking technology with aisles widths of up to four metres. With any freezer warehouse storage system having aisles for lift-trucks to manoeuvre and turn-around, a very important question should be asked: “what are we really freezing?” The answer is air and aisles.
With the cost of energy, property and labour constantly increasing, freezer warehouse owners should look at new technologies such as high-rise Automated Storage and Retrieval Systems, or better yet, Mobile Pallet Racking, which uniquely addresses building and warehouse heights under 15 metres.
Mobile Racking uses conventional selective pallet racks mounted on carriages and moving on running rails and guide rails embedded directly into concrete floor. Since energy expenses in a freezer warehouse are second only to labour costs, it makes sense to double the amount of pallet locations inside the building or reduce the initial building size. This gets back to the question: does the warehouse owner want to freeze product or freeze aisles? Doubling the amount of pallet positions can reduce the total cost per pallet position by as much as 40% in new construction projects, and can reduce utility bills by as much as 50%.
What if you don’t need more pallet storage locations? High-density storage solutions such as Mobile Racking result in a much smaller building footprint by up to 45%. A significant reduction in energy loss (and utility bills) also ensues, due to the correspondingly-smaller roof structure reducing air escape. The other cost savings of a smaller, more efficient Mobile Racking warehouse include a 35% lower overall investment in construction costs and a reduction of up to 49% in utility costs.
Mobile Racking is a pragmatic, smart, state-of the-art solution for freezer warehousing.