-
Notifications
You must be signed in to change notification settings - Fork 0
Life Support
The air in a station or a ship needs to be carefully regulated to maintain a healthy balance of gasses and temperatures. Humans work best at 20% of oxygen, and an inert diluent is needed, like nitrogen, to reduce risk of fires. Waste products, like carbon dioxide, will need to be removed, and either reprocessed or vented.
Oxygen needs to be kept within a safe range. Too much and you will suffer from oxygen toxicity and burst into flame while giggling yourself to a crisp, too little, hypoxia and an excellent smurf impression. Oxygen can be made via hydrolysis of water, or via the Bosch reaction from CO2.
Carbon dioxide is the primary waste gas of humans. Too much will cause carbon dioxide poisoning. Carbon dioxide can be removed via high pressure liquefaction, or via pressure swing adsorption. It can be converted into elemental carbon and oxygen via the Bosch process. CO2 scrubbers are a short-term solution also, although disposing of the filter elements can be tricky due to their hazardous nature.
Nitrogen is the primary diluent of choice, and used to reduce the risk of fire. Nitrogen is not normally consumed or produced, but may need occasional replenishment due to leaks, displacement by other gases and ruptures of the hull.
A simple pressure gauge can be used to monitor the air pressure of a station or ship, and it is trivial to connect one to an HIC card to allow a DCPU to monitor air pressure.
While it is important to monitor pressure, it's not enough in most cases. Without knowing the levels of the various gasses, you risk inadvertently poisoning or suffocating yourself. Air composition can be measured with a standard gas chromatograph.
Gasses can be pulled from or pushed to the interior of a vessel via air vents. Proper pressure differentials to maintain flow can be provided by the use of pumps, and an array of valves can be used to control the flow of gasses. When allowing gasses to flow from a high pressure to a low pressure, a pump is not needed, but a valve is recommended. This serves a helpful and preserving purpose when half of the station is obliterated by a passing comet.
Gasses can be combined relatively simply, but the separation is much more complicated. The standard system involves the liquefaction of the desired gas, and then separation of the liquid. The conditions of liquefying vary for each gas. Bear in mind that this is an energy-intensive process, and takes significant time to re-establish a safe equilibrium in any significant volume.
Carbon dioxide can be liquefied without the need of low temperatures by the relatively simple expedient of compressing the gas mixture to a sufficiently high pressure. This is also true for human bodies. The pressure required to liquefy and separate CO2 varies depending on temperature, but one point is at about 3379810 pascals and 0 degrees celsius.
Oxygen and Nitrogen can be separated by cryogenic liquefaction. Nitrogen will liquefy at 63.18 degrees kelvin, and Oxygen at 54.36 degrees kelvin.