While a silo can be attached to a starbase simply for storage, this would be hugely inefficient. Their primary use is as storage in any of a wide variety of starbase manufacturing processes.
Silos are limited to a single stack of items, and must be offlined to be emptied.
Reactors do not provide storage for the materials they work on. Instead, they are linked to one or more silos to provide the materials they are to work with.
In addition to using silos as a source for materials, silos are also used as sinks (destinations) for materials. While Reactors do this, Moon Harvesting Arrays also use silos as destinations. Each of these structure types needs to be linked to a silo of some sort to hold the product of the structure.
A silo may be connected simultaneously as a sink (to a harvesting array, for instance), and as a source (say, to a reactor). In this configuration, the product of the harvesting array is moved to the silo for each cycle of the array. And each time the reactor cycles, if the silo has material available, it can be drawn out by the reactor to be processed. See POS refining for greater detail.
Silos are managed via the Control Tower Management screen.
While silos can hold refined ore, Refining Arrays cannot automatically empty into a silo.
There are currently 6 varieties of silo, differing largely in what they store.
Differing only in what items they store, these 5 silos are otherwise identical:
- Silo - The baseline standard, used to store or provide most resources.
- General Storage - stores commodities used in production of boosters, as well as byproducts of the booster manufacturing process.
- Biochemical Silo - used to store gas cloud materials
- Hazardous Chemical Silo - used to store uncut booster materials
- Catalyst Silo - for catalysts used in manufacturing 'improved' or 'strong' booster varieties.
- Hybrid Polymer Silo - for polymers used in the production of hybrid components.
- Coupling Arrays are small silos commonly used to prevent production loss. They are discussed below.
The Coupling Array is a generic silo that is used primarily as a buffer for other silo types in a production line. It has a capacity of only 1,500 m3, but requires only 10,000 MW and 155 Tf.
Anything produced by a structure that cannot contain it (reactors, mining arrays, etc) will be lost, if it is produced while the attached silo is offline. Coupling arrays are intended to provide space to store these materials on a temporary basis.
A coupling array is inserted between the source and the silo. That is, the working structure is connected to the coupling array as a source, and the coupling array is connected as a source to the silo. In this arrangement, if the silo is offline (or is full), the material is stored in the connecting array. When the silo goes online, the material in the connecting array is moved on to the silo.
Coupling arrays as silos
It is worth noting that a coupling array is itself a silo, albeit with a small capacity. It can thus be connected as a source to structures such as reactors (to provide materials just as a silo normally would), or to other coupling arrays as very small storage. While this is a high-maintenance situation (needing tending every 15 hours or so), it has lower CPU needs, allowing for more structures to be online at the same time. If the drain (via reactor or refining array) is close to as fast as the supply (from a mining array), it may be all that is required.
Doing without coupling arrays
Coupling arrays are a convenience item. It is entirely possible to use silos without them. The risk is that mistimed maintenance can result in a cycle of production being lost.
Production cycles are controlled by the Control Tower. The control tower cycle time can be discovered by reducing the fuel available to the tower. When the tower cycles next, it will send a 'low fuel' message to the appropriate parties. The timing of this message can be used to gauge safe windows of opportunity.