8 ms·

With the caveat that all published "plans" for the thing were probably meant as a PR stunt the plan called for passively cooling it[1]. That part actually does

by avar 2y ago

With the caveat that all published "plans" for the thing were probably meant as a PR stunt the plan called for passively cooling it[1]. That part actually doesn't seem implausible, it's right on the Red Sea, which is quite hot on the surface, but cools down as you you go deeper into it[2]. So (and this is just my speculation) they could have a large undersea pipeline to a depth of say 1km, and use the heat the building itself to pull up and distribute that cold water through cooling ducts throughout the structure. They were also planning to desalinate seawater, so such a system would perform the double duty of pulling that seawater into the building. 1. https://www.spectator.co.uk/article/why-i-admire-saudi-arabia-s-monstrous-new-city/ https://www.spectator.co.uk/article/why-i-admire-saudi-arabi... 2. https://os.copernicus.org/articles/16/149/2020/ https://os.copernicus.org/articles/16/149/2020/

alangibson 2y ago
How are we pumping the water if the power is out? I guess they're would be diesel generators for that in reality. We need an engineer to calculate the flow needed because given how far away the far end is from the water that could end up behind one huge generator, not to mention the size of the pipes. It's worth mentioning that they don't seem to be burying any massive water pipes so this isn't likely to be done in reality.
- jasongill 2y ago
  Gravity? This is what water towers are for. (not to say that this project isn't a total farce, but at least the issue of pumping water without electricity was solved hundreds of years ago)
  - GeoAtreides 2y ago
    How would gravity help pumping water from deep in the Red Sea up into buildings?
    - jasongill 2y ago
      the same way that water towers work - when the pumps are running (power is on), you pump water into the tower; then, when the pumps fail, gravity continues to provide water pressure as water drains from the tower. The water tower effectively acts as a "battery" in the system, storing energy (and water) and then releasing it as needed
      - GeoAtreides 2y ago
        But then the water won't be cool...
        jasongill 2y ago
        I didn't design the project, but I would imagine that moving water would be cooler than stagnant water. Other pre-industrial revolution pump designs like a hydram pump could keep cool water moving from the sea as well
  - eviks 2y ago
    Also, wouldn't water in those towers heat up?
- avar 2y ago
  See e.g. [1], so they could either funnel air into the ocean and back up for direct temperature exchange, or alternatively use the breeze generated top-to-bottom in the building to drive "active" pumps. Or just have Olympic-sized swimming pools in the basement that you've actively pumped water into. If the pumps are out they'll have a lot of thermal inertia. 1. https://www.archdaily.com/975502/geothermal-energy-using-the-earth-to-heat-buildings-and-generate-electricity https://www.archdaily.com/975502/geothermal-energy-using-the...
- whazor 2y ago
  We also have humans in space at the moment. Normally the answer would be fault tolerance or similar engineering solutions. Furthermore, if the building is decently isolated (HR++ sun-blocking glass exists), it should be able to handle some air conditioning downtime.
yourusername 2y ago
Some of it is right on the Red Sea but the "building" is proposed to be 170 km long. One end of the building will be over 100km from the sea, that's quite a distance to pump cold water without it heating up. Also wouldn't this be like the elevator problem in tall buildings? The first few kilometers of the line will need to have pipes sized for the cooling water of the 165km behind it eating up interior volume. Will pumping water from the sea, passing it through a heat exchanger and then pumping water 150km inland through insulated pipes even be more energy efficient than a AC?
- avar 2y ago
  > One end of the building will > be over 100km from the sea, Well, that part's easy. You put the non-citizen service workers on that end, you didn't think MBS was planning to provide them with AC, did you? :-) Talk about a disincentive to show up to work before sunrise and leave after dark. > Also wouldn't this be like > the elevator problem in tall > buildings? No, the vertical pipes in the building will branch off from the horizontal pipes running along it, the vertical height is trivial by comparison. > The first few kilometers of the > line will need to have pipes > sized for the cooling water of > the 165km behind it eating up > interior volume. Firstly you'd bury the pipe, if it's at a depth of just 10 meters the average soil temperature at depth really helps, even before insulating it. Secondly, by having it run in a loop you'd drastically reduce the energy to pump it. It'll take no more energy to pump water up 10m or 1km, as long as your outlet pipe is also at the same depth. > passing it through a heat > exchanger [...] be more energy > efficient than a AC? The whole thing is obviously ridiculous, but cost-benefit analysis doesn't really enter into what's ultimately an ego project enacted by royal degree. I was just pointing out that once you're willing to invest the sort of money Saudi Arabia has in upfront costs, there's no reason the end result (no matter how ridiculously expensive) can't be sustainable and passively cooled.
antonvs 2y ago
I love the way people describe what's basically a fantasy as though it could be implemented tomorrow. Do a Mars colony next.
- jraines 2y ago
  If we were at a point where the Line was feasible in terms of engineering and economics, we probably would be almost to the point of being able to put a colony on Mars
- somenameforme 2y ago
  Try to take yourself back to the past and imagine the idea of putting a seemingly endless number of electrical poles everywhere to carry telephony and electrical signals anywhere in the country, instantly. Poles that would become completely inoperable if the cable was damaged, lethal to anybody who touched them, fire hazards waiting to happen in case of natural disaster or just deterioration, and so on endlessly. And now imagine doing this in a world where there was no federal tax, the GDP was pennies (relative to today), and state of the art technology was us being on the verge of discovering that handwashing before surgery was a good idea. Really! [1] And the big goal here was to be able to put up 'electric lanterns.' It sounds so pie in the sky as to be unbelievable. And indeed it probably would never, in a million years, happen today. But it did happen in the past, and for that we owe our predecessors quite the debt! The point I make with this is that we have just an unimaginably vast level of economic power today, but it's mostly being squandered. We should be trying out grand ideas, endlessly. If we can make them work - awesome, we've radically improved the world and humanity - our descendants will thank us. If they fail, we can call it a jobs program -- certainly a much better one than trying to make stuff to go kill people half way around the globe. [1] - https://en.wikipedia.org/wiki/Ignaz_Semmelweis https://en.wikipedia.org/wiki/Ignaz_Semmelweis
  - jemmyw 2y ago
    > Try to take yourself back to the past and imagine the idea of putting a seemingly endless number of electrical poles everywhere to carry telephony and electrical signals anywhere in the country, But that's not what we did. Folks at the start of the process might have imagined that eventual situation, but they built up small networks, then a skeleton network with human connections (telegraph), then human driven routing. You can't just point at those mega infrastructure items we already have and say oh we have that so we can just apply that to another because that glosses over the whole and very long process of getting from mini projects to mega ones.

by avar 2y ago

alangibson 2y ago

How are we pumping the water if the power is out? I guess they're would be diesel generators for that in reality. We need an engineer to calculate the flow needed because given how far away the far end is from the water that could end up behind one huge generator, not to mention the size of the pipes. It's worth mentioning that they don't seem to be burying any massive water pipes so this isn't likely to be done in reality.

jasongill 2y ago
Gravity? This is what water towers are for. (not to say that this project isn't a total farce, but at least the issue of pumping water without electricity was solved hundreds of years ago)
- GeoAtreides 2y ago
  How would gravity help pumping water from deep in the Red Sea up into buildings?
  - jasongill 2y ago
    the same way that water towers work - when the pumps are running (power is on), you pump water into the tower; then, when the pumps fail, gravity continues to provide water pressure as water drains from the tower. The water tower effectively acts as a "battery" in the system, storing energy (and water) and then releasing it as needed
    - GeoAtreides 2y ago
      But then the water won't be cool...
      - jasongill 2y ago
        I didn't design the project, but I would imagine that moving water would be cooler than stagnant water. Other pre-industrial revolution pump designs like a hydram pump could keep cool water moving from the sea as well
- eviks 2y ago
  Also, wouldn't water in those towers heat up?
avar 2y ago
See e.g. [1], so they could either funnel air into the ocean and back up for direct temperature exchange, or alternatively use the breeze generated top-to-bottom in the building to drive "active" pumps. Or just have Olympic-sized swimming pools in the basement that you've actively pumped water into. If the pumps are out they'll have a lot of thermal inertia. 1. https://www.archdaily.com/975502/geothermal-energy-using-the-earth-to-heat-buildings-and-generate-electricity https://www.archdaily.com/975502/geothermal-energy-using-the...
whazor 2y ago
We also have humans in space at the moment. Normally the answer would be fault tolerance or similar engineering solutions. Furthermore, if the building is decently isolated (HR++ sun-blocking glass exists), it should be able to handle some air conditioning downtime.

yourusername 2y ago

Some of it is right on the Red Sea but the "building" is proposed to be 170 km long. One end of the building will be over 100km from the sea, that's quite a distance to pump cold water without it heating up. Also wouldn't this be like the elevator problem in tall buildings? The first few kilometers of the line will need to have pipes sized for the cooling water of the 165km behind it eating up interior volume. Will pumping water from the sea, passing it through a heat exchanger and then pumping water 150km inland through insulated pipes even be more energy efficient than a AC?

avar 2y ago
> One end of the building will > be over 100km from the sea, Well, that part's easy. You put the non-citizen service workers on that end, you didn't think MBS was planning to provide them with AC, did you? :-) Talk about a disincentive to show up to work before sunrise and leave after dark. > Also wouldn't this be like > the elevator problem in tall > buildings? No, the vertical pipes in the building will branch off from the horizontal pipes running along it, the vertical height is trivial by comparison. > The first few kilometers of the > line will need to have pipes > sized for the cooling water of > the 165km behind it eating up > interior volume. Firstly you'd bury the pipe, if it's at a depth of just 10 meters the average soil temperature at depth really helps, even before insulating it. Secondly, by having it run in a loop you'd drastically reduce the energy to pump it. It'll take no more energy to pump water up 10m or 1km, as long as your outlet pipe is also at the same depth. > passing it through a heat > exchanger [...] be more energy > efficient than a AC? The whole thing is obviously ridiculous, but cost-benefit analysis doesn't really enter into what's ultimately an ego project enacted by royal degree. I was just pointing out that once you're willing to invest the sort of money Saudi Arabia has in upfront costs, there's no reason the end result (no matter how ridiculously expensive) can't be sustainable and passively cooled.

antonvs 2y ago

I love the way people describe what's basically a fantasy as though it could be implemented tomorrow. Do a Mars colony next.

jraines 2y ago
If we were at a point where the Line was feasible in terms of engineering and economics, we probably would be almost to the point of being able to put a colony on Mars
somenameforme 2y ago
Try to take yourself back to the past and imagine the idea of putting a seemingly endless number of electrical poles everywhere to carry telephony and electrical signals anywhere in the country, instantly. Poles that would become completely inoperable if the cable was damaged, lethal to anybody who touched them, fire hazards waiting to happen in case of natural disaster or just deterioration, and so on endlessly. And now imagine doing this in a world where there was no federal tax, the GDP was pennies (relative to today), and state of the art technology was us being on the verge of discovering that handwashing before surgery was a good idea. Really! [1] And the big goal here was to be able to put up 'electric lanterns.' It sounds so pie in the sky as to be unbelievable. And indeed it probably would never, in a million years, happen today. But it did happen in the past, and for that we owe our predecessors quite the debt! The point I make with this is that we have just an unimaginably vast level of economic power today, but it's mostly being squandered. We should be trying out grand ideas, endlessly. If we can make them work - awesome, we've radically improved the world and humanity - our descendants will thank us. If they fail, we can call it a jobs program -- certainly a much better one than trying to make stuff to go kill people half way around the globe. [1] - https://en.wikipedia.org/wiki/Ignaz_Semmelweis https://en.wikipedia.org/wiki/Ignaz_Semmelweis
- jemmyw 2y ago
  > Try to take yourself back to the past and imagine the idea of putting a seemingly endless number of electrical poles everywhere to carry telephony and electrical signals anywhere in the country, But that's not what we did. Folks at the start of the process might have imagined that eventual situation, but they built up small networks, then a skeleton network with human connections (telegraph), then human driven routing. You can't just point at those mega infrastructure items we already have and say oh we have that so we can just apply that to another because that glosses over the whole and very long process of getting from mini projects to mega ones.