4 ms·

> https://www.bbc.com/news/business-61483491 https://www.bbc.com/news/business-61483491 Nuclear desalination like on naval ships is the answer. US and Russian

> https://www.bbc.com/news/business-61483491 https://www.bbc.com/news/business-61483491 Nuclear desalination like on naval ships is the answer. US and Russian ships already have the technology, it just needs to be scaled for use on land.

eru 3y ago
Nuclear power in general would be the answer to a lot of energy problems. But the general public in most places doesn't like it.
- pvaldes 3y ago
  Is not just a question of preferences, there are risks also. If the problem is that we need lots of energy to create pressure to separate salt from brine, well... I figure out that there is a lot of free "all that you can eat" pressure in the sea bottom. The problem would be to calculate if moving all this weight up and down the sea (and in open sea) would be economical or not. Or of would unavoidably lead to people cutting corners and release part of the salt to the deep water ecosystems. Deep water masses are salty yet so a small amount of salt would impact less here than if released on surface, thats for sure. In any case, physic laws about density and mass are our friend. Things either float or sink without extra energy added.
  - pvaldes 3y ago
    Having all of this in mind, I would go further and propose to regulate by law changing the material of the deep sea submarine ballasts. It seems technically doable and would have some benefits 1) Lesser impact on deep sea ecosystems. No human trace left behind. Disposable loads of iron or concrete will remain forever in the bottom. If we use salt or sand instead the impact on fragile deep sea ecosystems seems reduced. The organisms there are adapted naturally to deal with very salty water. The sand or salt ballast could be released gradually over a bigger surface reducing even more the impact over a particular spot or colony 2) Improved economics? To dump valuable iron made with valuable energy into the sea seems a suboptimal solution. Substitute it with some common by products that are yet in the area and don't need to be transported from a mine far away could save some money probably. Containers of ballast would be fully recyclable also. Ships could be adapted to literally making part the ballast on the open sea while in campaign, instead to need to carry all of it from a port. 3) Extra safety. If your load weight gets stuck by a net you are trapped in the bottom forever, With a ballast of sand or salt you have the extra possibility of open a few escape valves and let the concentrated salt go away. You can also release part of the weight much more gradually. After a while the submarine would tend to float and ascend automatically even if the energy supply would have been entirely lost in an accident. Having the machine on the surface (or closer to the surface) would save millions and would made a big difference on humanitary and economical aspects of the rescue operation. A damaged submarine can be still repaired. Building another would be much more expensive. Dunno about the possible negative aspects, more volume required for example, but would deserve thinking about it a little more.
    - eru 3y ago
      > Having all of this in mind, I would go further and propose to regulate by law changing the material of the deep sea submarine ballasts. Which country's law? There are many of them. > 1) Lesser impact on deep sea ecosystems. No human trace left behind. There's barely any submarines around. This is a drop in the bucket. > 2) Improved economics? If it improves economics, why do you need to force people with regulation?
      - pvaldes 3y ago
        If Titan proved something is that economics is not the only factor what matters here.
  - Ajedi32 3y ago
    > I figure out that there is a lot of free "all that you can eat" pressure in the sea bottom. > Things either float or sink without extra energy added. That seems intuitively wrong... where is the energy coming from in this scenario? It's like saying we could use the pressure at the bottom of the ocean to spin a turbine and get free electricity. I guess the obvious problem that sticks out in my mind is that once you've filled this submersible with desalinated water, how do you surface? A typical submarine does that by pumping water out of the ballast tank, but doesn't that require the exact same pressure that you just used to fill the cabin with desalinated water?
    - Ajedi32 3y ago
      Here's an even more interesting physics brain teaser: Imagine you put a reverse osmosis membrane at the bottom of the ocean and connected it to a pipe filled with fresh water leading to the surface. The pressure at the bottom of the pipe would be less than the pressure at the bottom of the ocean, since fresh water weighs less than salt water. In this setup, would an endless supply of fresh water flow through the membrane and bubble out the top of the pipe? I'm guessing not, but I'm having a hard time understanding why.
      - Ajedi32 3y ago
        Wild guess: maybe only the partial pressure[1] controls whether water will flow through the membrane, and the partial pressure of freshwater in this scenario is identical on both sides? [1]: https://en.wikipedia.org/wiki/Partial_pressure https://en.wikipedia.org/wiki/Partial_pressure
      - eru 3y ago
        > I'm guessing not, but I'm having a hard time understanding why. Second law of thermodynamics.
        pvaldes 3y ago
        Laws of thermodynamics aren't really useful here. They are perfect for explaining universe, and notoriously bad for predicting local events when you zoom and focus at a fine grain level and add time. Life beings are apparently breaking or "delaying" this laws all the f*ng time. In any case nobody is trying to make a perpetual movement machine. The goal is to create a cheaper way to extract salt from saltwater, and use the pressure gradient at the sea to put apart brine and water could be a solution waiting for an engineer (in my opinion). It is assumed that will not be free in terms of energy. It doesn't matter as long as is slightly better than the current solution. Would be much faster than waiting for the sun so it does not need to be cheaper than that. It just needs to be able to replace the last energy-expensive phase of our current solution by another process that is cheaper or faster.
  - eru 3y ago
    > I figure out that there is a lot of free "all that you can eat" pressure in the sea bottom. Have you heard of the second law of thermodynamics? There's also lots of all-you-can-eat heat in any piece of matter, eg sea water or rock. But that doesn't mean you can get at it for anything useful, without a heat differential (or a pressure differential).
    - pvaldes 3y ago
      Hum, I wonder where we could find a heat differential and a pressure differential in this planet... if we except the ocean, and the land, and the atmosphere, and any place with an organism able to fart...
ClumsyPilot 3y ago
Actually solar powered desalination makes a lot more sence - solar is much cheaper and you don't need 24/7 properties of nuclear. so you are overpaying for no reason. We cam store huge quantities of water, sometimes a year's worth. So intermittency is not a prohlem. The idea of floating nuclear reactors used for whatever was floating around for a while, but won't happen with government support. It is really just another approach to modular reactors, not a terrible one, but free market wont do it. What would make more sence, is making all our large cargo ships nuclear powered, and reducing emissions that way

eru 3y ago

Nuclear power in general would be the answer to a lot of energy problems. But the general public in most places doesn't like it.

pvaldes 3y ago
Is not just a question of preferences, there are risks also. If the problem is that we need lots of energy to create pressure to separate salt from brine, well... I figure out that there is a lot of free "all that you can eat" pressure in the sea bottom. The problem would be to calculate if moving all this weight up and down the sea (and in open sea) would be economical or not. Or of would unavoidably lead to people cutting corners and release part of the salt to the deep water ecosystems. Deep water masses are salty yet so a small amount of salt would impact less here than if released on surface, thats for sure. In any case, physic laws about density and mass are our friend. Things either float or sink without extra energy added.
- pvaldes 3y ago
  Having all of this in mind, I would go further and propose to regulate by law changing the material of the deep sea submarine ballasts. It seems technically doable and would have some benefits 1) Lesser impact on deep sea ecosystems. No human trace left behind. Disposable loads of iron or concrete will remain forever in the bottom. If we use salt or sand instead the impact on fragile deep sea ecosystems seems reduced. The organisms there are adapted naturally to deal with very salty water. The sand or salt ballast could be released gradually over a bigger surface reducing even more the impact over a particular spot or colony 2) Improved economics? To dump valuable iron made with valuable energy into the sea seems a suboptimal solution. Substitute it with some common by products that are yet in the area and don't need to be transported from a mine far away could save some money probably. Containers of ballast would be fully recyclable also. Ships could be adapted to literally making part the ballast on the open sea while in campaign, instead to need to carry all of it from a port. 3) Extra safety. If your load weight gets stuck by a net you are trapped in the bottom forever, With a ballast of sand or salt you have the extra possibility of open a few escape valves and let the concentrated salt go away. You can also release part of the weight much more gradually. After a while the submarine would tend to float and ascend automatically even if the energy supply would have been entirely lost in an accident. Having the machine on the surface (or closer to the surface) would save millions and would made a big difference on humanitary and economical aspects of the rescue operation. A damaged submarine can be still repaired. Building another would be much more expensive. Dunno about the possible negative aspects, more volume required for example, but would deserve thinking about it a little more.
  - eru 3y ago
    > Having all of this in mind, I would go further and propose to regulate by law changing the material of the deep sea submarine ballasts. Which country's law? There are many of them. > 1) Lesser impact on deep sea ecosystems. No human trace left behind. There's barely any submarines around. This is a drop in the bucket. > 2) Improved economics? If it improves economics, why do you need to force people with regulation?
    - pvaldes 3y ago
      If Titan proved something is that economics is not the only factor what matters here.
- Ajedi32 3y ago
  > I figure out that there is a lot of free "all that you can eat" pressure in the sea bottom. > Things either float or sink without extra energy added. That seems intuitively wrong... where is the energy coming from in this scenario? It's like saying we could use the pressure at the bottom of the ocean to spin a turbine and get free electricity. I guess the obvious problem that sticks out in my mind is that once you've filled this submersible with desalinated water, how do you surface? A typical submarine does that by pumping water out of the ballast tank, but doesn't that require the exact same pressure that you just used to fill the cabin with desalinated water?
  - Ajedi32 3y ago
    Here's an even more interesting physics brain teaser: Imagine you put a reverse osmosis membrane at the bottom of the ocean and connected it to a pipe filled with fresh water leading to the surface. The pressure at the bottom of the pipe would be less than the pressure at the bottom of the ocean, since fresh water weighs less than salt water. In this setup, would an endless supply of fresh water flow through the membrane and bubble out the top of the pipe? I'm guessing not, but I'm having a hard time understanding why.
    - Ajedi32 3y ago
      Wild guess: maybe only the partial pressure[1] controls whether water will flow through the membrane, and the partial pressure of freshwater in this scenario is identical on both sides? [1]: https://en.wikipedia.org/wiki/Partial_pressure https://en.wikipedia.org/wiki/Partial_pressure
    - eru 3y ago
      > I'm guessing not, but I'm having a hard time understanding why. Second law of thermodynamics.
      - pvaldes 3y ago
        Laws of thermodynamics aren't really useful here. They are perfect for explaining universe, and notoriously bad for predicting local events when you zoom and focus at a fine grain level and add time. Life beings are apparently breaking or "delaying" this laws all the f*ng time. In any case nobody is trying to make a perpetual movement machine. The goal is to create a cheaper way to extract salt from saltwater, and use the pressure gradient at the sea to put apart brine and water could be a solution waiting for an engineer (in my opinion). It is assumed that will not be free in terms of energy. It doesn't matter as long as is slightly better than the current solution. Would be much faster than waiting for the sun so it does not need to be cheaper than that. It just needs to be able to replace the last energy-expensive phase of our current solution by another process that is cheaper or faster.
- eru 3y ago
  > I figure out that there is a lot of free "all that you can eat" pressure in the sea bottom. Have you heard of the second law of thermodynamics? There's also lots of all-you-can-eat heat in any piece of matter, eg sea water or rock. But that doesn't mean you can get at it for anything useful, without a heat differential (or a pressure differential).
  - pvaldes 3y ago
    Hum, I wonder where we could find a heat differential and a pressure differential in this planet... if we except the ocean, and the land, and the atmosphere, and any place with an organism able to fart...

ClumsyPilot 3y ago

Actually solar powered desalination makes a lot more sence - solar is much cheaper and you don't need 24/7 properties of nuclear. so you are overpaying for no reason. We cam store huge quantities of water, sometimes a year's worth. So intermittency is not a prohlem. The idea of floating nuclear reactors used for whatever was floating around for a while, but won't happen with government support. It is really just another approach to modular reactors, not a terrible one, but free market wont do it. What would make more sence, is making all our large cargo ships nuclear powered, and reducing emissions that way