You are an officer in the US Navy and have volunteered for s

You are an officer in the US Navy and have volunteered for submarine duty. As an environmental engineer, your job is to ensure the health and safety of all personnel on the submarine. You monitor an air purification system that automatically generates oxygen to maintain and N₂/O₂ ratio of 3.75 and a water vapor mole fraction of 0.017. At what CO₂ level (in ppm) must you set the alarm to ensure that the O₂ never drops below 19.5%?

Solution

Living in a sealed environment for days, weeks or months with other humans creates many new atmosheric problems.

Using electronic control equipment, the problem can be resolved.

Electrolytic oxygen generators : Using pure water, a mixture of potassium hydroxide, and 350-1050 amperes of electricity, a grouping of electrolytic cells  provide more than sufficient breathable oxygen for a submarine crew. The electrolytic cells are enclosed within the electrolytic oxygen generator cabinet shown on the right. “Excess” produced oxygen can be stored in large oxygen flasks external to the submarine pressure hull for later use. The hydrogen produced is safely disposed-of. A newer unit, the Low Pressure Electrolyzer, using state-of-the-art proton exchange membrane electrolysis cells is now being used in newer submarines.

But the availability of pure water inside the submarine is not stored. To this reason sea water is used to prepare pure water through desalination procress.

Depending upon the depth of submarine located , levels of O₂ changes .

So, to ensure that O₂ never drops below 19.5% CO₂ level inside the submarine ranges/ differs as 350 - 400 ppm. At that initial level alarms can be set to ensure the health and safety of all people in the submarine