Results 31 to 36 of 36
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2018-06-28, 04:12 PM (ISO 8601)
- Join Date
- Nov 2007
- Location
- Cippa's River Meadow
- Gender
Re: How many plants are needed to keep someone alive?
Can I ask where you get that value of 206g from?
Page 5 Table 2 says an average male crewman needs 0.62kg food solids a day and 3400 Calories a day. Assuming they're eating pure carbohydrate at 4 Calories per gram that's still 850g worth of pure starch/sucrose, let alone the much less energy dense nori which has 35 Calories per 100grams.
Again, I'm not following your math:
22.0 m2 by 2 cm panel is (220000 cm2 x 2 cm) 440,000 cm3 = 440,000 mL = 440 Litres at a density of 20g dry weight per litre.
Halve the density, you double the volume, so 880 litres at 10g dry weight per litre. Sticking with 2cm deep panels means you'll also need to double the surface area, so 44.0m2 per person daily.
The C. vulgaris paper, the maximal rate of cell growth was ~1.5 g dry cell weight per litre per day with a starting biomass concentration of 5 g dry cell weight per litre. Figure 5A seems to indicate rate of growth is broadly independent of the starting concentration, so assume that 1.5 g DCW per litre per day is still applicable at 10 g DCW per litre.
880 litres would therefore generate an extra 1.32kg dry cell weight of algae a day, which if processed into nori with 100% efficiency, gives you 462 Calories which is about 14% of a male astronaut's needs a day.
This is assuming you set the flow rate on the panels so that it takes 24 hours for algae to transit across; any faster than that and you'll need to look up more detailed rate of growth and carbon capturing variables. Similarly if you start making the panels thicker, you'll need to look up light penetration into water and the light blocking effects of algae.
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2018-06-28, 07:29 PM (ISO 8601)
- Join Date
- Jun 2013
- Location
- Bristol, UK
Re: How many plants are needed to keep someone alive?
I can't believe it'll be anything other than lettuce that they try first, it's fast growing and moderately edible. Mind you, lack of variety will make any food appalling in a matter of weeks.
The end of what Son? The story? There is no end. There's just the point where the storytellers stop talking.
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2018-06-28, 07:35 PM (ISO 8601)
- Join Date
- Aug 2008
Re: How many plants are needed to keep someone alive?
In terms of hiding major engineering problems in plain sight the term "relevant filters" is a thing of beauty.
Also my proposal is that the panels are the CSTRs, and that instead of the central rotor you use something else to mix them better suited for slow laminar flow. You've got a large, fairly flat panel with a liquid-algae outlet and inlet stream, using nutrient enriched water on inlet, at a slow trickle. Then the panels themselves are mixed as evenly as possible. You also wouldn't need the regular feeds in or out (though an oxygen filter per CSTR would be needed as an outlet stream, given that we're basically building the separator in).
There's a level of handwaving here, of course, but no more than for the rest of this spaceship.
*Which does run into a laminar mixing issue, another source of fun. There's a lot of these.I would really like to see a game made by Obryn, Kurald Galain, and Knaight from these forums.
I'm not joking one bit. I would buy the hell out of that. -- ChubbyRain
Current Design Project: Legacy, a game of masters and apprentices for two players and a GM.
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2021-12-21, 05:07 AM (ISO 8601)
- Join Date
- Dec 2021
Re: How many plants are needed to keep someone alive?
If you have a long-term plan of growing trees to produce oxygen, 1 tree for every 10 people is enough. One mature tree with enough branches and tree can produce enough oxygen in a season for 10 people to breathe clean oxygen for a complete year.
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2021-12-21, 08:44 AM (ISO 8601)
- Join Date
- May 2007
- Location
- The Land of Cleves
- Gender
Re: How many plants are needed to keep someone alive?
One mature tree produces zero oxygen, on net. Plants only produce net oxygen while they're still growing.
Time travels in divers paces with divers persons.
—As You Like It, III:ii:328
Chronos's Unalliterative Skillmonkey Guide
Current Homebrew: 5th edition psionics
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2021-12-21, 09:08 AM (ISO 8601)
- Join Date
- Mar 2007
- Location
- Grognardia
- Gender
Re: How many plants are needed to keep someone alive?
Metamagic Mod: how many Necroposters are required to keep an expired thread alive?
(Avatar by Cuthalion, who is great.)