New Sci Fi Setting Seeds

[Astromancer]

Originally Posted by Daigoro

Recovery from sewage?

Given that the main virtue of vertical farming, other than environmental protection for the crops, is tight recycling of resources and wastes. Of course making wastes into resources is also central to the idea. So Daigoro, I assume you're right.

[Astromancer]

Originally Posted by Luke Bunyip

Cough seaweed cough.

A further reason for the sea cities.

[Daigoro]

Originally Posted by Astromancer

Given that the main virtue of vertical farming, other than environmental protection for the crops, is tight recycling of resources and wastes. Of course making wastes into resources is also central to the idea. So Daigoro, I assume you're right.

Well, you'd also need to capture phosphates from food consumed, but again in arcologies that would be easier.

[AlexanderHowl]

One of the major problems with arcologies is the energy issue and the waste heat issue. Arcologies require a lot of energy to function, around 1 MW per person, as they must replace natural sunlight with artificial sunlight for the purpose of multi-level agriculture. If you have a global population of 10 billion, that would mean energy requirements would be around 10 PW.

In order to get that with solar, you would need solar arrays with 30% efficiency to cover the equivalent of 1/4 of the surface of the Earth, which would be impossible to do without massive orbital construction or the annihilation of the natural environment. Alternatively, you could use fusion which, at a maximum efficient of 40%, would produce 15 PW of waste heat, meaning that the total heat generated by the arcologies would be around 25 PW, the equivalent of around 1/5 the energy received by the Earth from the Sun. The Earth would increase it temperature by 13 K due to the excess heat produced by human civilization.

[ericthered]

Originally Posted by AlexanderHowl

One of the major problems with arcologies is the energy issue and the waste heat issue. Arcologies require a lot of energy to function, around 1 MW per person, as they must replace natural sunlight with artificial sunlight for the purpose of multi-level agriculture. If you have a global population of 10 billion, that would mean energy requirements would be around 10 PW.

1 MW is a higher number than I'm used to hearing. Do you mind referencing where you're getting it? It seems to be mostly a food number: Iceland, the country with the largest per capita energy budget, uses about 6 kw per person. The food numbers do get pretty high, but I've seen numbers an order of magnitude lower than what you're giving. Actually, I've seen people go two orders of magnitude lower, but that was using close to perfect efficiencies (other than the horrible efficiency of plants) and was made to show how you can't cover a planet with a 100 story city.



You're absolutely right that the energy budget and heat removal is the problem with large indoor farms though. we don't grow vertically on a large scale now because the sun shines just as much on horizontal surfaces as vertical ones.



You can mitigate your heating problems with shades that filter out the least desirable sunlight frequencies, but that probably counts as "Massive Orbital Construction".

[AlexanderHowl]

Well, photosynthetic efficiencies are around 1%, with only 50% of the energy becoming food, so you require around 2.1 GJ per person per day for a 2500 calorie vegan diet, so that end up being around 30 kW per person for light (assuming an 80% efficiency). Most people will want a richer diet though, with chocolate, dairy, and meat, so you require 10x that amount, around 300 kJ per person for light. The remaining 700 kW per person is required for fertilizer production from atmospheric nitrogen, HVAC, industry, pumping water, recycling, sewage treatment, etc.

Now, you could likely reduce the energy consumption by 90%, but the resulting arcology would only provide the barest sustenance for its people. That would be suitable for a Matrix style arcology, where the vast majority of the population lives in VR, attended by automated systems. If you want to live a proper lifestyle though, one good enough to make people want to live in an arcology, you need the 1 MW per person. It is one of the reasons why orbital colonies are cheaper than arcologies.

[ericthered]

Originally Posted by AlexanderHowl

Well, photosynthetic efficiencies are around 1%, with only 50% of the energy becoming food, so you require around 2.1 GJ per person per day for a 2500 calorie vegan diet, so that end up being around 30 kW per person for light (assuming an 80% efficiency). Most people will want a richer diet though, with chocolate, dairy, and meat, so you require 10x that amount, around 300 kJ per person for light. The remaining 700 kW per person is required for fertilizer production from atmospheric nitrogen, HVAC, industry, pumping water, recycling, sewage treatment, etc.

ok, you've accounted for a 30kW minimum made a solid argument for increasing that to 300kW for anyone who has the choice to do so.



You don't get to rounding up 200% for everything else. The energy budget numbers of the modern world show you can fix someone's nitrogen, treat their sewage, run their temperature control and produce modern first world amenities on a 6 kw budget. I can see an argument for a less virgin world multiplying that number, but even multiplying it by 10 gives you 60kw, a generous number still under a tenth of the number you're trying to give.



I don't know what the energy budget for building cooling the vertical farms looks like, but I really doubt its x2 the cost of lighting the farms. Most of all that energy is a result of the plants crappy 1% energy efficiency. And we were stating that the big problem with vertical farming was the heat from running the lights, not the other issues.

[Daigoro]

There's a handy table here - https://en.wikipedia.org/wiki/List_o...ion_per_capita

Qatar and Iceland come top with 25kW per capita. Admittedly the table doesn't account for outsourcing your energy consumption for various resources, but I don't see it reaching 1MW in a comprehensive calculation. In any case, arcologies can outsource energy consumption for various commodities themselves. Factories don't have to be inside their walls.

Also- the world being discussed doesn't have a 10 billion population in arcologies. We're looking at a cluster of Pacific Rim first world countries who've built sea cities and I don't believe have put their entire populations therein.

HVAC- I believe there are zero-energy air conditioned skyscrapers that have been built now, using passive cooling. How this works inside an arcology is a different question, but I don't believe arcology builders would just rely on old-fashioned brute-force refrigerative air conditioning.

But the question I brought up in my earlier post remains- how does exacting homework on the viability of arcologies make for an interesting setting?

[Astromancer]

Originally Posted by AlexanderHowl

One of the major problems with arcologies is the energy issue and the waste heat issue. Arcologies require a lot of energy to function, around 1 MW per person, as they must replace natural sunlight with artificial sunlight for the purpose of multi-level agriculture. If you have a global population of 10 billion, that would mean energy requirements would be around 10 PW.

In order to get that with solar, you would need solar arrays with 30% efficiency to cover the equivalent of 1/4 of the surface of the Earth, which would be impossible to do without massive orbital construction or the annihilation of the natural environment. Alternatively, you could use fusion which, at a maximum efficiency of 40%, would produce 15 PW of waste heat, meaning that the total heat generated by the arcologies would be around 25 PW, the equivalent of around 1/5 the energy received by the Earth from the Sun. The Earth would increase its temperature by 13 K due to the excess heat produced by human civilization.

First, this society has TL9 fusion, by the high tech rules. So heat isn't that much of an issue. The "Arcologies" are mainly cities that have had to enclose themselves to resist the effects of sea level rise. Most towns and cities are not apologies. Geodesic domes, built to create areas of more pleasant climate, are a thing.

[Astromancer]

Originally Posted by Astromancer

Hot Times

This thread on The End of the World suggests a setting to me, basically, an extension of my Posting from a comment to a setting.

The sea cities are mainly made up of structures like large ships floating with neutral buoyancy just far enough under the water to be safe from any and all storms. They are generally too large to be practical ships, but as they rarely move, the size of the typical city unit isn't a real problem. Assume the units are about ten times as wide and long as an aircraft carrier. They can, in emergencies, also sink a few yards deeper or rise to the surface. There are specialized buildings that fill functions like parks and civic centers that seem like floating islands. All of these specialized building can sink to avoid storms. They can also ride out some pretty brutal storms.

The sea cities take into the political territories many of the Pacific islands. Example: One district of the sea cities is named American Samoa and the territorial capital is on that island.


The Southwestern USA is fairly miserable. Floods of desperate refugees have come North to survive. The USA is very near a crisis in food generally, and this is worse in the rural areas. If the floods of refugees are taken in, people will have to starve. If the refugees aren't taken in, they will still starve. The cities and towns of the Southwest are cyberpunk crossed with post-apocalyptic hells, except in the gated communities of LA which are pure Hollywood glam, now with extra sparkle. If you watched the Hunger Games steal freely from the more disturbingly glam aspects of the Capital. But no vomitoria. These people aren't that sick. Sick but not that nasty.

There are some other areas that blend cyberpunk and post-apocalyptic in this setting. LA is meant to be the most blatant and nasty. New York is meant to be an infuriating blend of hope and horror. The Sea Cities are meant to be anxious places of hard won hope. Japan is meant to be a place of quiet paranoia and hidden horrors of madness. Europe is a more straightforward post-apocalyptic area. Although the Nordic countries, Scotland and Ireland, are meant to be areas of embattled hope.