Author Topic: Designing an Earth base  (Read 4672 times)

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Online 2397

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Designing an Earth base
« on: November 06, 2017, 10:51:32 AM »
I'm thinking of writing a low-tech, semi-dystopian sci-fi story, with possibly the most ridiculous concept being the home facility; a self-sustained base inside a mountain. I'm looking for some opinions on what doesn't make sense or isn't feasible.

The origin of the base is not important, as long as it would've been possible to construct with reasonable amounts of resources. Drilling into rock, setting up structures, without threatening the structural integrity of the rock.



The blue-green background is gneiss rock. The orange-brown is the transition to open space. Obviously it wouldn't be entirely square and straight, but the scale is otherwise 1 pixel=10 cm.

Access tunnels: The top- and rightmost sections go to the outside environment, and include ventilation, drainage, sewage, and electric wires. The Secondary has backup systems to the Primary, except for it being the path for the source of electricity.

The outer grey section is a 600 or 460 cm diameter tunnel, the black in the middle is a set of hefty doors. The entire facility needs to be resistant to moderate earthquakes (up to 6.0).

Not sure if the tunnels are deep enough. The red sections being about 18 and 27 meters, so the outside structure would have to be somewhat steep for there to be solid rock all around.

The white stripes are airtight doors.

Solar panels: 256 m². Maybe it has to be much more than that. Not to scale/the correct placement and orientation. I wonder how important it is to catch all of the sun, vs. making sure they're optimally placed for the peak. And if it would be worth it to make them track with the Sun, vs. making them easier to secure by having them entirely fixed in place.

Batteries: I don't yet know how much power the facility will require, but I hope that 600 kWh in batteries will be enough for the facility to run on solar panels alone. They will degrade over time/need replacements.

Farm: This is the biggest challenge for me. It should be built to feed 20 people indefinitely. Depicted are 4 separate sections for up to 4 different atmospheric conditions. 256 m² usable space, or about 600 m3 including sprinklers and whatever else.

Not sure about the area, volume, whether there should be soil or all hydroponics, the energy requirements, crop rotation, composting, whether it would be worth the trouble to reclaim human waste, whether it's more efficient to regularly grow crops from seeds or grow the crops continuously, and whether there should be a day-night cycle.

And how big a part could the farm play in life support?

Reading this query, I might be off by a factor of 5. Or 2, with aeroponics. Under natural light, without layering. So maybe it is within reach of current technology to produce enough food within that amount space. But it makes sense now that having a 1:1 ratio of solar panels to growing space is far from enough. Maybe the peak power requirements will be in the megawatt range.

Storage: 307.2 m3 of storage space for food. 307.2 m3 of storage space for toilet paper. Or maybe the toilets have bidets.

Not sure if storage should be one big section that's cold, dry, and low on oxygen, or if there would be enough of a difference in optimal conditions that it should be multiple fully segregated compartments, or if the way to go is one section with independently refrigerated rooms.

Utility rooms: I figure a couple of transformers, one for direct power from the solar panels, one for charging/running power off of the batteries. And earthing. Maybe another way of dealing with excess electricity.

The bottom room is essentially a garage.

Waste processing; Ultimately, a lot of it will end up in a landfill, but at least there should be a small compost section attached to the living quarters. Maybe a waste compressor, sterilizing equipment (an oven?), and a centrifuge.

Water; Well, pressure tank, water heaters. It might be a bit tricky to bore a well from inside a mountain, so maybe it would be better/more realistic to bring in water from an external well. And more efficient to have water heaters in a room where you need a higher ambient temperature. But for maintenance's sake it seems more practical to have it all in one place.

Living quarters: Bedrooms, bathrooms/washroom, gym, computers, media rooms, dining area, kitchen with local food storage.

Environmental conditions and ventilation: Basically, the outside environment is not suitable for long term exposure. Temperature regulation is easy enough. The air otherwise has oxygen and nitrogen, not necessarily in ideal amounts. I don't know how difficult it is to separate those out or to filter everything else.

External, minimally outfitted greenhouses could produce some food with variable results.

What's missing, and what won't work, or would work better in a different way? Say this cost 20 million USD to build, what alternatives (in the context of long term independent survival) might someone rather spend it on?
« Last Edit: November 09, 2017, 08:06:12 PM by 2397 »

Online Noisy Rhysling

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Re: Desinging an Earth base
« Reply #1 on: November 06, 2017, 10:52:51 AM »
Look up the Cheyenne Mountain facility.
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Online Rai

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Re: Desinging an Earth base
« Reply #2 on: November 06, 2017, 10:57:52 AM »
I smell Dwarf Fortress

Online Noisy Rhysling

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Re: Desinging an Earth base
« Reply #3 on: November 06, 2017, 11:00:36 AM »
You need to look up how many square feet of hydroponics is required to support one person for one year.
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Offline MTBox

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Re: Desinging an Earth base
« Reply #4 on: November 07, 2017, 02:28:51 PM »
For electricity, using transformers and rectifiers is only necessary if you are trying to facilitate a Non-generated standard. You can reduce a lot of that need, by using what gets generated. Example: DC generation = DC powered lights and appliances, not AC. The power on the US Grid is "stepped down" and "rectified" because of the Transmission requirements. You are not exactly running a cross-country distribution system.

Offline Dr Barton

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Re: Desinging an Earth base
« Reply #5 on: November 08, 2017, 09:54:44 PM »
In aquaponics, a reasonable rule-of-thumb is 3 parts hydroponics to 1 part aquaculture. Keep in mind that this ratio includes supplemental feed for the aquaculture. To reduce supplemental feed, you'd need to add more "hydroponics" space. This "hydroponics" space could be additional hydroponics to provide feed for herbivorous fish (such as tilapia) or to provide feed for herbivorous insects (such as crickets, mealworms, and cockroaches) to feed more omnivorous fish (and other livestock and humans). That said, you probably need to plan on a 3:1 ratio of farm space to human space even assuming stacked growing trays.

You're also going to have to consider storage (and possibly manufacturing) space for LED's an solar panels (or their raw materials) for lighting and powering the facility. I'm also pretty sure that solar array is way to small for the type of facility that you're proposing. Your water and waste utility rooms should be directly linked to your farm space. That is where you are going to recycle your wastes and purify your water. Batteries may be hard to maintain in the long haul. There is also the problem of disposing of the hazardous wastes that they produce. If I might suggest, consider using a weight storage system for the bulk of your energy storage needs. You use the electricity to crank weights up. When you need electricity or compressed air, you allow the weights to descend running a generator or compressor. It's basically a very large version of a grandfather clock. Use iron-nickel batteries. There are durable and significantly less toxic than lead acid. You can stockpile a lot of iron and nickel plates and sodium hydroxide for the electrolyte. When the electrode corrode, a clever person can probably figure out how to electrolytically extract the nickel from the water. You may not be able to recycle that nickel easily but, at least, you can store it in a solid form and location that isn't likely to poison you.

Online 2397

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Re: Desinging an Earth base
« Reply #6 on: November 09, 2017, 08:25:44 AM »
More space, more energy, maybe not so much regulation of energy, although I worry about the explosive potential of the total battery capacity.

Maybe weights would be safer. Would it be as reliable? Hopefully it will become easier to maintain over time as you get used to what's going on and can optimize things, rather than more difficult as the system builds up faults. How much space does weight storage require per kWh? There was a discussion about something similar here, which provides a basis.

Last rough estimate I did was for an average of 2 MWh per day, operating the grow lights 50% of the time. So it doesn't have to be all in the batteries, but it means 1500-3000 m² of solar panels at 22% efficiency, depending on local conditions. Given 400 kW peak capacity and $2 per W, the panels cost $800 k.

I think I need to define a cost for digging out space, to put a limit on how much internal space there can be. Or figure out the cost of the necessary equipment, and how much time it would take for a small group of trained amateurs to do it. The Svalbard Global Seed Vault total cost was $9000 per square meter of "floor area", possibly $5000 accounting for all of it. It's the most comparable structure I know of. That would put the cost for the space I haven't quite worked out yet to well over $65 million.
« Last Edit: November 09, 2017, 08:58:43 AM by 2397 »

Offline junki

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Re: Desinging an Earth base
« Reply #7 on: November 09, 2017, 01:05:54 PM »
Will there still be a water cycle outdoors? Could you use old-skool hydropower? For power, or as an additional coolant for the base itself and/or the solar panels.
Could you drill really deep holes for geothermal energy? Or, how about locating in Iceland or some similar place.

stupid ideas,
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Online 2397

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Re: Desinging an Earth base
« Reply #8 on: November 09, 2017, 02:11:30 PM »
There will be more going on outside, and very likely hydropower of some sort, but it wouldn't be exclusive to this facility. If there's something big enough to have a reservoir, it would be reserved for winter use when it's not about to be full.

And what's further out will be more challenging to keep operational.
« Last Edit: November 09, 2017, 02:24:07 PM by 2397 »

Offline Drunken Idaho

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Re: Desinging an Earth base
« Reply #9 on: November 09, 2017, 02:52:57 PM »
In such a world, I wouldn't like the idea of anything which can't be recycled--specifically, TP in your description so far. You mention bidet, which is an easy out if you have water to waste (which would make a lot of this much easier if water source and volume is not a concern)... but before you go there, I think (as a great fan of sci fi and fantasy) it's creative and  unexpected solutions to problems such as this one which can really make a story.
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Offline daniel1948

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Re: Desinging an Earth base
« Reply #10 on: November 09, 2017, 07:00:31 PM »
Am I the only one who wonders what "desinging" means? It makes me think of cutting the burnt edges off of a piece of toast.
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Online 2397

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Re: Desinging an Earth base
« Reply #11 on: November 09, 2017, 08:08:49 PM »
Am I the only one who wonders what "desinging" means? It makes me think of cutting the burnt edges off of a piece of toast.

It's how you go from sung to unsung.

So, making sure there's nothing too remarkable going on, but hopefully still a worthy concept.
« Last Edit: November 09, 2017, 08:10:56 PM by 2397 »

Offline Silfio

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Re: Designing an Earth base
« Reply #12 on: November 10, 2017, 10:44:00 AM »
I think the batteries are a weak point  :-\ .What do you think about underground hydrogen storage? https://en.wikipedia.org/wiki/Underground_hydrogen_storage
 You don't need maintenance/replacement , ideal for apocalyptic future!. Maybe hidrotermal energy will be  an option to the solar.

Offline starnado

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Re: Designing an Earth base
« Reply #13 on: November 10, 2017, 10:53:04 AM »
If you vented a hydrothermal system at a high point and allowed the steam to condense you could store massive reservoirs of water and use hydroelectric turbines to recover stored energy whenever needed. Excess solar power could be used to pump water uphill into the reservoirs.
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Offline Silfio

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Re: Designing an Earth base
« Reply #14 on: November 10, 2017, 11:31:42 AM »
Obviously if you want to survive you need redundant systems.But I think the conventional batteries there isn't an option for long term situation.I would like to make some easy -super simplification calculate to see the approximate dimension of the installation , and $$.