Quote Originally Posted by Brother Oni View Post
The problem is that the link which mentions the use of algae ponds for CO2 capture, doesn't mention their depth or the species, only the dry cell weight concentration.

Say we pick an algae earmarked for biofuel potential, Chlorella vulgaris. From this link, the optimal concentration of chlorella vulgaris is 20g dry weight per litre without light intensity shenanigans.

1 L over 1 square metre means you only need a panel 0.1 cm thick to hit that target of 439.9 m2 per person per day.

From the paper, their largest reaction vessel was no more than 4cm diameter, so presumably your panels can't get more than 2cm thick without the yield efficiency dropping off, making (439.9 m2 x 0.1cm / 2 cm) 22.0 m2 per person per day the smallest you could go. That's still about double the 11m2 bamboo footprint, but with a significantly reduced vertical footprint.

Algae panels aren't as nice to look at though.

Edit: With regard to the algae concentration disparity in the lab and the algae ponds, I suspect that 20g dry weight per litre is probably not feasible outside of small scale lab conditions with tender loving care and you'd probably ideally want a lower concentration so that your algae has space to grow into as it captures the CO2.
I think you'ld want to select your algae for maximum edibility/nutritional value. Which, since this is a SF scenario, would presumably be easy to engineer into whatever algae you want, but still, let's assume half that density.

The algae paper would then give us a yield of 10g dry weight of algae per liter per day.
The NASA paper indicates we want 206 g of food per person per day (dehydrated, since we are using dry weight to figure algae production.)

So 21 liters of production volume per person per day would roughly balance out oxygen production, CO2 absorption, and gives you all your bulk food requirements. That's a single 1m by 1m by 2cm panel, per person per day. Considerably more compact that bamboo, and all the nori you can eat.