Electrolyzer

Converts Water into Oxygen and Hydrogen.
Becomes idle when the area reaches maximum pressure capacity.

Research

Air Systems

Dimensions

2×2 tiles

Usage

Electrolyzers require more planning than other oxygen sources as not only do they require a water supply via pipes and pumps, but the hydrogen must also be handled. Another aspect is the temperature of the oxygen being created. The gas outputs are always 70 °C / 158 °F or hotter, so it is advised to cool the oxygen before using it in the core of the colony, or to cool the colony itself.

Electrolyzers may be used to meet a colony's Oxygen needs for as long as there is a source of water. The produced hydrogen will rise up and can be collected at ceilings using a Gas Pump. Alternately the electrolysis can be performed in a small air-tight room and the gases pumped out before the pressure rises above the electrolyzer's operational limit. The hydrogen can then be separated from the oxygen using a Gas Filter and directed to a Hydrogen Generator, producing a small amount of power. The Oxygen can be distributed within the colony via Gas Vents or sent to other uses such as an Atmo Suit Dock, Oxylite Refinery, or a Telescope. Multiple vents can be used, instead of a single vent, to ensure that there is always a place for the Oxygen to go as an individual vent will stop releasing oxygen as soon the vent's environment has reached its operational the pressure limit. A Geyser may be used to provide water for an Electrolyzer-based oxygen supply.

To supply oxygen for 1 duplicant requires 112.5 g/s, or 67.5 kg/cycle of water used (assuming the electrolyzer works at 100% capacity).

Heat economy

Consider cooling water as little as possible or even pre-heat it before delivering into electrolyzers. The input water has a higher specific heat capacity than the gases produced, which makes gases easier to cool down afterwards.

It gets better – assuming that the base is at 0 °C / 32 °F, 1 kg of mixed oxygen and hydrogen produced at 70 °C / 158 °F carries as much heat as 1 kg of water at 19.45 °C / 67.01 °F, which means that, when using water above 19.45 °C / 67.01 °F, the electrolysis becomes net heat negative, removing $4.179 kDTU/°C/s$ (1 kg water per second $\times$ the specific heat of water) per degree centigrade above that), up to 70 °C / 158 °F when the outputs also begin to rise in temperature and the efficiency drops to around 3 kDTU/°C. With near-boiling 96 °C / 204.8 °F water, the heat removed is ~288kDTU/s, which is comparable to 3.6 AETNs.

Note, that electrolyzer will not process water but will instead release steam into the environment if the input is too hot.

As a corollary, feeding water colder than 19.45 °C / 67.01 °F will create heat.

That said, the 70 °C / 158 °F output is sure to cook any farm relying on a steady temperature of 30 °C / 86 °F or lower without any additional heat transfer/deletion. For each kilogram of water input, the electrolyzer outputs mass with a heat capacity of ~1.161 $\frac{DTU}{g^{\circ} C}$ / 0.65 $\frac{DTU}{g^{\circ} F}$ . The hot hydrogen typically (1) remains in the system, (2) is deleted along with its heat by hydrogen generator(s), or (3) is later cooled by other means. Given that a duplicant consumes 100 g/s oxygen, cooling the total output of an electrolyzer requires $116.1 DTU/°C/s$ per duplicant, or, for the +40 °C / +72 °F drop from 70 °C / 158 °F to 30 °C / 86 °F, 4.64 kDTU/s. This is slightly less heat than is deleted by a single fertilized Wheezewort in oxygen (~5 kDTU/s).

If we consider cooling only the oxygen, the heat change is $100.5 DTU/°C/s$ per duplicant, or for the same +40 °C / +72 °F temperature change, ~4 kDTU/s. In contrast, cooling the corresponding input water (112.6 g) for the same temperature difference would require ~18.8 kDTU/s, ~4.7 $\times$ more. In other words, cooling only the oxygen reduces the cooling needed by ~78.6%.

Mechanics

The Electrolyzer has a maximum pressure limit of 1.8 kg. It checks the pressure of any Gases on the four tiles it occupies; Liquids are not counted toward this limit.

When below the pressure limit, the Electrolyzer emits both Hydrogen and Oxygen once per second on its top-left tile. Because a cell can only contain one element at a time, one of the gases is displaced to a neighboring cell. Emission prefers merging into existing gas in nearby cells, which can be used to influence which tiles the gases end up in.

Tips

The Electrolyzer is an Algae-free way of producing oxygen and should be researched before you run out of algae.
Filling the Electrolyzer with anything other than Water will cause damage to it. This limitation includes Polluted Water.
The Electrolyzer has a 10 kg internal reserve, which lasts for 10 seconds under ideal conditions.
The Electrolyzer will not remove Food Poisoning or Slimelung germs within the water, and will output the germs with the Oxygen. Both germs will gradually die out in Oxygen.
Using High Pressure Gas Vents will more efficiently spread oxygen in the base (however too high pressure will cause popped eardrums which give stress, to avoid this use automation to shut off the vent at a sufficiently high pressure below 4kg).
The Electrolyzer can be combined with the Anti Entropy Thermo-Nullifier to cool down its output for very little cost in Hydrogen. In addition, the AETN it can prevent the electrolyzer from overheating if the two are close enough.

Bugs

Placing the Electrolyzer with two Gas Pumps on the left and right sides of a $6 \times 2$ sealed room will result in significant amount of hydrogen disappearing, effectively producing only 75 g/s of hydrogen (about 66% of what it should be). The workaround is to make the room 3 tiles high (with pumps and electrolyzer placed on the ground).