Introduction
When pallet storage volumes increase, simply adding more racks or forklifts may not be enough. A pallet ASRS can automate storage and retrieval while making better use of vertical space, reducing manual handling, and improving warehouse throughput.
However, not every automated pallet storage solution works in the same way. Stacker cranes, shuttle systems, AGVs, and different aisle configurations can be combined to meet different requirements for storage density, throughput, flexibility, and warehouse layout.
In this guide, we explore 12 types of pallet ASRS and explain how each solution works, where it fits best, and what kind of warehouse requirements it can address. This will help you compare different approaches before choosing an automated pallet storage solution for your facility.
Pallet Rack-Based ASRS
A pallet rack-based ASRS uses multi-level racks to store palletized goods vertically. Forklifts or automated equipment such as stacker cranes move pallets into and out of storage locations.
Using pallets as standard load units makes goods easier to handle, transport, and store. The multi-level rack layout also helps make better use of available warehouse space.
Typical applications:
- Manufacturing plants
- Distribution centers
- Supermarket warehouses
- Finished-goods and raw material storage
Double-Deep Pallet ASRS
A double-deep pallet ASRS stores two pallets deep in each rack position. The storage equipment can access both the front and rear pallet locations, allowing more pallets to be stored in the same space.
This layout increases storage density and can reduce the number of aisles and equipment needed. It works best when high storage capacity is more important than having direct access to every pallet.
Typical applications:
- Manufacturing warehouses
- E-commerce warehouses
- Finished-goods storage
- Warehouses with large volumes of similar products
Aisle-Changing Stacker Crane ASRS
In this type of pallet ASRS, a stacker crane can move between different storage aisles. This allows one crane to serve multiple aisles instead of staying in a single aisle.
By sharing equipment between aisles, the system can improve crane utilization and provide more flexibility for different storage and retrieval needs.
Typical applications:
- Multi-aisle warehouses
- Manufacturing facilities
- Distribution centers
- Warehouses that need flexible aisle access
Transfer-Car-Based Aisle-Changing ASRS
A transfer-car-based pallet ASRS uses a transfer car to move the stacker crane from one aisle to another. Once the crane reaches the target aisle, it can continue storing or retrieving pallets there.
This design allows one stacker crane to serve multiple aisles, improving equipment utilization and providing greater flexibility for warehouse operations.
Typical applications:
- Large distribution centers
- Multi-aisle warehouses
- Large-scale manufacturing warehouses
- Facilities that require frequent aisle changes
Dual Stacker Cranes in a Single Aisle
This pallet ASRS uses two stacker cranes in the same storage aisle. The two cranes can work independently or handle storage and retrieval tasks at the same time.
Using two cranes increases the handling capacity of the aisle and helps speed up pallet storage and retrieval. It is a good option for warehouses with frequent inbound and outbound operations.
Typical applications:
- Distribution centers
- E-commerce warehouses
- Supermarket distribution centers
- High-throughput pallet warehouses
Telescopic Fork Stacker Crane ASRS
This type of pallet ASRS uses a stacker crane with telescopic forks. The forks can extend and retract to reach pallet locations at different depths.
This design gives the stacker crane more flexibility when working with different rack configurations and storage depths. It is useful when a warehouse needs to store pallets in deeper positions or handle different storage layouts.
Typical applications:
- Automotive parts warehouses
- Manufacturing warehouses
- Warehouses with different rack depths
- Facilities that need flexible pallet storage
Shuttle-Assisted Pallet ASRS
A shuttle-assisted pallet ASRS combines stacker cranes with shuttle vehicles. The stacker crane moves pallets to the required rack area, while the shuttle carries them deeper into the rack.
This combination can speed up pallet handling and make better use of deep storage locations. It is a practical option when high storage density and efficient pallet movement are both important.
Typical applications:
- E-commerce warehouses
- Distribution centers
- Manufacturing warehouses
- High-density pallet storage facilities
Mother-and-Child Shuttle ASRS
A mother-and-child shuttle ASRS uses two types of shuttle vehicles. The mother shuttle moves along the main aisle, while the child shuttle enters the rack to store and retrieve pallets.
This combination allows pallets to be stored deep inside the racks while keeping the main transport path efficient. It is well suited to warehouses that need high storage density and large pallet storage capacity.
Typical applications:
- Large manufacturing warehouses
- Raw material warehouses
- High-density pallet storage
- Large-scale distribution centers
Four-Way Shuttle Pallet ASRS
A four-way shuttle pallet ASRS uses shuttle vehicles that can move in multiple directions inside the rack. They can travel forward, backward, and change aisles when needed, allowing pallets to be stored and retrieved more flexibly.
This design makes better use of the available storage space and allows the warehouse layout to be adapted to different storage needs. It is especially useful when high storage density and flexible pallet movement are both required.
Typical applications:
- Cold chain warehouses
- Food and beverage warehouses
- Manufacturing warehouses
- High-density pallet storage facilities
AGV-Based Pallet ASRS
An AGV-based pallet ASRS uses automated guided vehicles to move pallets between storage and operating areas. AGVs can navigate the warehouse automatically and work with stacker cranes, racks, conveyors, and other equipment.
By automating pallet movement, this setup can reduce manual handling and support more flexible warehouse operations. It is a good choice for facilities that want to connect storage with other automated material handling processes.
Typical applications:
- Smart factories
- Automated warehouses
- Manufacturing facilities
- Distribution centers
Circular Rail Aisle-Changing ASRS
A circular rail pallet ASRS uses a looped rail layout to allow stacker cranes to move between multiple storage aisles. The cranes can switch aisles along the rail and continue pallet storage or retrieval without requiring a separate crane for every aisle.
This design improves equipment utilization and provides more flexibility in warehouses with many storage aisles. It is especially useful when cranes need to serve different aisles frequently.
Typical applications:
- Large logistics centers
- Multi-aisle warehouses
- High-density pallet warehouses
- Facilities with frequent aisle changes
Single- and Double-Mast Stacker Crane ASRS
A stacker crane is a core piece of equipment in many pallet ASRS solutions. It moves pallets through three basic motions: horizontal travel, vertical lifting, and fork extension.
Single-mast stacker cranes have a compact structure and are suitable for lighter loads and high-frequency operations. Double-mast stacker cranes provide greater stability and are better suited to heavier pallets and higher storage levels.
Typical applications:
- Manufacturing warehouses
- Logistics and distribution centers
- Pharmaceutical warehouses
- Automotive parts warehouses
- High-bay pallet storage facilities
Conclusion
There is no single pallet ASRS solution that fits every warehouse. The right choice depends on factors such as storage capacity, pallet size and weight, required throughput, available space, and the level of automation you need.
The 12 types covered in this guide offer different approaches to pallet storage and handling. Comparing their strengths and limitations can help you find a solution that fits your warehouse layout and daily operations.
For a more accurate solution, a warehouse assessment and layout design can help determine the right combination of racks, stacker cranes, shuttles, AGVs, and other equipment.
