Gas Reservoir

The Gas Reservoir is a mid-game storage building for gases. It occupies a 3×5 footprint in the world, but like other reservoir-style buildings it stores a much larger amount than its footprint suggests, holding up to 1000 kg of gas. It is especially useful when you want to buffer a production chain, smooth out pipe flow, or keep a reserve of a gas for later use without dedicating a large open chamber to the task.

One of its biggest advantages is convenience: it has both input and output ports, so it can be inserted directly into a gas pipe system without extra machinery. It also does not block Duplicant access, which makes it easier to build into compact utility rooms than loose gas storage. In practice, Gas Reservoirs are often used to hold outputs from systems such as Electrolyzers, where they provide a buffer that helps cover short disruptions and makes resource monitoring easier.

A Gas Reservoir is also good at evening out temperature swings. Gas entering the reservoir exchanges heat through the output-port tile and the tile directly below it, which means the contents do not directly heat or cool the whole building. If both of those tiles are kept in vacuum, the gas inside can be stored with essentially no heat exchange at all. This makes the building useful for holding very hot or very cold gases without immediately transferring that temperature to the surrounding base.

For best results, keep Gas Reservoirs out of extreme environments when possible. If one is completely damaged, it releases its contents, and escaping gas is much harder to contain than spilled liquid or solid material. Submerging the reservoir in Chlorine will quickly kill germs on its contents, which can be useful when storing contaminated gases.

A few practical notes:

• The reservoir can store mixed gases, but output behavior is influenced by gas type. Heavier gases are favored, and if multiple gases are stored at the same amount, Hydrogen tends to remain.
• Its automation output can be paired with a NOT Gate to keep filters or related machinery active only after the tank reaches a chosen fill level.
• The fill limit can be set from 0 kg up to 500 kg, with a minimum nonzero setting of 0.001 kg.
• The building can be disabled by a Duplicant; when disabled, it stops outputting contents but continues accepting input.
• It can also be disabled automatically by destroying the tile support beneath it, for example by placing it over a Mechanized Airlock and opening it.
• Compared with storing gas directly in the world, it is much more space-efficient and far more convenient for piping, though for some resources storing them in liquid or solid form is still even denser.

For fuel logistics, Gas Reservoirs are often not the best possible storage medium, but they are still useful. For example, if a colony intends to feed Hydrogen Generators, storing water in Liquid Reservoirs before processing may be denser than storing Hydrogen afterward; however, Gas Reservoirs remain valuable as the final buffer for the Hydrogen produced by Electrolyzers and pumps, especially when a large reserve is desired.