Multiple-weight unit load storage assignment strategies for energy efficient automated warehouses

Energy-efficient manufacturing claims for a change in warehousing operations management, moving from the traditional time-based perspective to the energy-based one. In automated storage and retrieval systems, this new approach leads to revise storage assignment policies, so that the least energy can be consumed by cranes for unit load movements. Dedicated energy-based policies and related zone shapes are analysed with particular attention to the role of unit load weight and the design option of rack stratification from floor to ceiling. Energy performance of dedicated, class-based, and random storage policies are then compared for different demand curves and rack shape. In order to enhance flexibility while maximising energy efficiency, new dynamic energy-based policies are also introduced and evaluated