5 ms·
At 20C, the maximum water content in air is 17.3 x 10^-3 kg/m^3. At 15% relative humidity, then, you can extract a maximum of 0.15 x 17.3g = 2.6g from every 1,
by ttul 4y ago
At 20C, the maximum water content in air is 17.3 x 10^-3 kg/m^3.
At 15% relative humidity, then, you can extract a maximum of 0.15 x 17.3g = 2.6g from every 1,000L of air.
If a person needs 5L/day for survival (I am making this up), then you’d need to dry out 5000 / 2.6 = 1,923L of air each day — that’s just short of two cubic meters…
If the density of people living in an area is 50 per square km, drying the air out to extract water would deplete the first meter of the atmosphere by 10%.
- conductr 4y agoIf those people are living there 5L/day is nowhere near enough water. They are doing more than just surviving. Using Arizona as an example, Google tells me 550L/day/person is actual usage. I know you just put an assumption in but this is a big gap.
- function_seven 4y ago1,923,000L per day, right? So each person would need just short of 2,000 m³ of air.
- TwistedWave 4y ago1,923m^3, not 1,923L
- bufferoverflow 4y ago> If a person needs 5L/day for survival (I am making this up), then you’d need to dry out 5000 / 2.6 = 1,923L of air each day You made a unit conversion mistake there. It's 1923 cubic meters, not liters.
- npc12345 4y agoAren't they equivalent?
- tomrod 4y agoliter = 0.001 Cubic meter I was curious so I looked it up because I also did not know, ref: https://www.google.com/search?q=liters+in+cubic+meter&oq=liters+in+cubic+meter https://www.google.com/search?q=liters+in+cubic+meter&oq=lit...
- ttul 4y agoCorrect. 5,000g / 2.6 g per m^3 = 1,923 m^3 Okay let’s say the bottom 10m of atmosphere is available for water making. That means there are 10 million cubic meters of air per square km, or per 50 people. We will need to dry out 1,923 x 50 = 96,150 cubic meters of air. But there is 10,000,000 available, meaning we are only drying out just under 1% of the air.
- ttul 4y agoAnd, for comparison, “ A 4-stroke engine with one litre displacement operating for 60 minutes at 2500 rpm is estimated to consume 1 L x 2500/2 rpm x 60 minutes/hour = 75,000 litres of air.” https://collaboration.cmc.ec.gc.ca/science/rpn/SEM/dossiers/2006/seminaires/2006-04-07/AirVolumes_CMOSBULLETINSCMO_latest.pdf https://collaboration.cmc.ec.gc.ca/science/rpn/SEM/dossiers/...