Let's say you live in an area where droughts are threatening life and farming. You want to produce fresh water, have a cordillera less than, say, 100 miles away from the sea, some empty ponds, some fresh water reservoirs, and enough energy (in the form of solar panels or whatever) to pump seawater to your ponds during spring and summer.Then, during winter, you use the freezing cold air to freeze the seawater (see this paper for some methods: https://www.nature.com/articles/s41545-022-00158-1), to the point of separating ice from the salt. You then move ice or pump fresh water to your fresh water reservoirs.As a bonus, you just obtained salt, lithium and other minerals from the saltwater, AND you can recover some of the energy you used to pump the water during summer.Could this be done? Can you find issues with this idea?
>>16882200cant we just use big centrifuges? we should have solved this problem ages ago
>>16882285>centrifuges>for desalinationwat. are you pretending?
Honestly it would be easier to set up a large pipeline. I'm surprised the United States hasn't done this, to pipe water from the Great lakes to California. A similar pipeline was created for oil to go from northern Alaska to Southern Alaska. Surely it could be done piping water instead of oil from one side of the country to the other.
>>16882606oil = moneywater = lol, who cares?
>>16882616I don't know, I feel like water is a more precious commodity. You don't bathe in oil, drink oil, farm with oil, etc.
>>16882622I'm saying that that's the mentality of politicians these days.you are 100% right that they could easily solve the problem simply with another pipeline, but they won't, because the corrupt fuckers don't actually care.similar shit happens in my south american country, btw. not even "leftists" who are in power "for the people" give a flying fuck about solving actual problems people have.
>>16882606So the great lakes get dried up too? Californians don't deserve water
The obvious problem is that regions that need water usually don't have cold winters. The only such country is Kazakhstan, but they don't really struggle with it.Another problem is to separate that "Ice + NACl crystals", how would you do that?
>>16882812>The obvious problem is that regions that need water usually don't have cold winters. The only such country is Kazakhstan, but they don't really struggle with it.anon, the whole american continent has a drought problem and a lengthy coast in the pacific.>Another problem is to separate that "Ice + NACl crystals", how would you do that?you could try reading the paper, googling or something. the tl;dr is: it happens naturally. you don't get 100% pure water, though, but IIRC purity depends on temperatures and other factors.
>>16882816>a lengthy coast in the pacific.+ mountains...
>>16882812>The obvious problem is that regions that need water usually don't have cold winters.For areas with mountains, you can see here that it gets freezing cold during winters:https://www.omnicalculator.com/physics/altitude-temperatureUse 0°C for To and 3000 for h, you'll get almost -20°C of temp. Eutectic point of saltwater is −21.2 °C.
>>16884749>just pump the water from the ocean up the mountain bro
>>16882816>you could try reading the paperHow would I know it contains methods if you stated "to the point of separating ice from the salt" and not further. You want us to do free job for you so later you'll invent or publish something and make money? Fuck you. Go hire smb.
>>16885657Well, yes, just do that. Maybe have a bunch of intermediate ponds or whatever.You can calculate how much energy you need, btw. 1 GW in solar panels can move a lot of water.>>16885687LMAO, you could google or ask a fucking LLM, anon. Don't be lazy, do some research, jfc...It happens naturally. Go freeze some brine and watch it happen. It will not be 100% pure fresh water, though.Here, I did some googling for you: https://www.scienceabc.com/pure-sciences/why-is-sea-ice-made-of-freshwater-when-oceans-are-salty.html
>>16885724I'm not lazy, I'm greedy. I only do fun stuff for free. You stuff isn't fun so you have to post memes together with exempts of the articles. If smb posts correct answer to your question, reinforce it with a hot chick picutre
>>16882200> be OP> stare at phase diagram for 5 minutes> "I have solved the global water crisis"> mfwLet me break this down for you, midwit.1. Gravity exists. To hit those sub-zero temps, you need altitude. Lifting 1000kg of water up 2000m costs ~7kWh. Reverse Osmosis at sea level costs ~3kWh. You are burning double the energy just to roleplay a glacier.2. Entrapment. Seawater doesn't freeze into clean ice cubes. It forms a slush matrix. Brine gets trapped in the lattice. You have to centrifuge and wash the ice with *more* fresh water to make it drinkable.3. Corrosion. Pumping warm seawater 100 miles uphill? Your pumps and pipes will die of chloride stress corrosion before the first winter.The only people doing this are lithium miners in the Andes (Eutectic Freeze Crystallization) because they want the *salts*, not the water. You didn't invent a free energy hack, you reinvented an inefficient mining technique.Lurk more and learn basic thermodynamics.
>>16886047>Lifting 1000kg of water up 2000m costs ~7kWhthanks for confirming what I knew. that's fucking NOTHING in terms of energy.>Reverse Osmosis at sea level costs ~3kWh. You are burning double the energy just to roleplay a glacier.try re-reading the OP... most of the energy used to lift the water could be recovered, AND you wouln't need any energy to freeze the water>Seawater doesn't freeze into clean ice cubesthat's why you'd be pumping it into fresh water ponds. you'd dilute most of the leftover brine. OR maybe could use the desalinated water for farming instead of human consumption.but, if you had taken a quick look at the paper, you'd have realized that different methods give different results, and some give better results (less salt) than others.>Your pumps and pipes will die of chloride stress corrosion before the first winterright, that's a problem I don't know anything about. still, do you really need metallic pipes? how long can the pumps survive before >The only people doing this are lithium miners in the Andes (Eutectic Freeze Crystallization) because they want the *salts*, not the waterbull fucking shit. they aren't doing any of this, they literally pumps saltware into ponds and let them dry for a year or 2. in the meantime, the lithium falls to the bottom of the pond, so they simply remove the salt layer and take the lithium.also, you don't even need to reach the eutectic point to freeze seawater.thanks for your opinion, chatgpt user.
>>16882320If you can add salt to water by stirring it, you can remove salt by stirring it
>>16886085>calls me ChatGPT>doesn't understand entropyTop kek. You're trying to "recover" energy from a system where you've already lost 30% to friction and turbine inefficiency, all to fight the Second Law.Listen, "genius":1. Dilution is not Desalination: Pumping seawater into freshwater ponds to "dilute brine" is just poisoning your reservoir. You're turning fresh water into brackish water. Congrats, you've achieved negative progress.2. Pipes: Plastic (HDPE) exists, sure. Enjoy the UV degradation and the cost of 100 miles of 48-inch diameter pipe. You're looking at billions in CAPEX to avoid a $3/m3 RO plant.3. Yield: To get drinkable water (<500 ppm) from 35,000 ppm seawater via freezing, you need multiple stages. Each stage loses mass. Your "free" winter air is a low-flux heat exchanger. You'd need the surface area of Rhode Island to get a glass of water.Go back to r/futurology with the other hopium addicts. The math doesn't check out.
>>16882200The real solution to desalination is sodium and chlorine capture. By decreasing the amount of water soluble molecules on Earth, ineffective water capture techniques will be made more effective.
>>16886151>Top kek. You're trying to "recover" energy from a system where you've already lost 30% to friction and turbine inefficiency, all to fight the Second Law.and? if you use energy from a PV plant, no one would give a shit about the energy spent, as long as the system keeps pumping water.also, do the fucking math. if you can recover, say, 60% from those 7kWh, how much energy did you end up spending? hint: it's less than 3kWh.>1. Dilution is not Desalinationare you retarded or just pretending? you process the water, dump whatever ice or fresh water you got in a (larger, obv.) fresh water pond, and you get water with practically 0% salt.again, did you even READ THE FUCKING PAPER? about half the methods shown in the paper have a 99%+ salt removal efficiency. what do you call that? what about the diluted version of that?>You're looking at billions in CAPEX to avoid a $3/m3 RO plant.you made me remember another benefit of a setup like this: you wouldn't end up dumping heavy saline water to the sea.regarding economics: that's a valid point. water from RO plants is already very expensive, so I guess something like this would need to be subsidized (that's why I said areas with droughts) unless someone makes it more efficient.>3. Yield: To get drinkable water (<500 ppm) from 35,000 ppm seawater via freezing, you need multiple stages. Each stage loses mass.let's see: 35,000 ppm x 0.01 = 350ppm. again, half the methods mentioned in the paper can do that.like I already said: from that mass, you get salt and other minerals. so you can also recover some $$ there, and maybe even a bit of energy.>Your "free" winter air is a low-flux heat exchanger.what is wind?sure, you still need a large area... that's exactly what the methods described in the paper use: a lot of area. so what?>The math doesn't check out.you couldn't even calculate the potential energy recovery kek>>16886246tell us, how much energy would that require?
>>16886256>seething so hard you forgot physics again>no one would give a shit about the energy spent>immediately tries to argue energy mathListen here, Dunning-Kruger.1. Friction, how does it work? You aren't just lifting vertically. You are pushing fluid 100 miles (160km). The Darcy-Weisbach equation is laughing at you. Over that distance, your head loss from friction destroys your "recovery" efficiency. You aren't getting 60% back. You'll be lucky to get 30% after turbine losses, pipe friction, and motor inefficiency. You are burning massive watts to move heavy water horizontally just to freeze it.2. Scale vs. Lab: "The paper said 99%!" Yeah, in a controlled lab setting with active washing. In a giant open pond? Wind blows dust/dirt in. Brine pockets get trapped. One warm day melts the brine back into the "fresh" ice. To get that 99%, you need mechanical scrapers and wash columns. Energy cost just went up again.3. The Lithium Delusion: Seawater has ~0.17 ppm Lithium. Andean brines have ~1,000 ppm. You would need to process 5.8 MILLION LITERS of seawater to get 1 kg of Lithium. You aren't mining; you're just making expensive salt piles.You're trying to build a Rube Goldberg machine to do what a standard RO plant does for pennies.
>>16886262>>no one would give a shit about the energy spent>>immediately tries to argue energy mathyou don't get it, do you?what's the difference between the following situations?- you use 10MWh to pump water, and you recover 6MWh- you use 1GWh to pump water, and you recover 600MWhdoes it matter how much water you pumped when talking about energy?>You aren't just lifting vertically. You are pushing fluid 100 miles (160km). The Darcy-Weisbach equation is laughing at you. Over that distance, your head loss from friction destroys your "recovery" efficiency. You aren't getting 60% back. You'll be lucky to get 30% after turbine losses, pipe friction, and motor inefficiencyfinally, some actual contribution with practical criticism in this thread. was what too difficult to say, that you didn't mention it from the start?according to google, plastic (HDPE, PVC, ...) piping has a much lower friction factor than steel, and of couse they don't corrode, so that's a given.what if you install more intermediate ponds? you lift water at ever step and then simply let it flow downhill. you know, areas with mountains are usually very hilly. you'd also benefit from this by, say, having water to control fires.you could also heat the water to reduce its density a bit.what if you use aqueducts instead of pipes?>Wind blows dust/dirt in. Brine pockets get trapped. One warm day melts the brine back into the "fresh" ice.sure. wind blows dust into lakes and similar places too. in this case you could process and remove the salt immediately, maybe?you aren't spending much energy on freezing the seawater, so who cares?also not sure why you got this idea that the pond has to be in the same place where the seawater freezing plant would be. they could be installed far from one each other.>You would need to process 5.8 MILLION LITERSthat's 5800 m3 of water. not too little but not a lot either.recovering lithium might not be worth it, but the salt and other minerals might be
>>16886303>heat the water to reduce its density a bit>water specific heat capacity = 4,184 J/kg°C>wants to spend megajoules of thermal energy to save kilojoules of pumping energy>mfwI was going to call you a midwit, but you're actively trying to break the laws of thermodynamics now. You want to heat the ocean to make it lighter? Do you understand how much solar surface area you'd need just to raise the temp 1 degree? And for what? A 0.02% density drop?>recovering lithium might not be worth it>Let's do the "fucking math" you asked for:>To get 1 KG OF LITHIUM ($15 value), you pump 5,800 TONS of water up 2000m.>Potential Energy = mgh = 5.8 x 10^6 kg x 9.8 x 2000m = approximately 113GJ.>That is 31,400 kWh.>At a charitable $0.05/kWh, you just spent $1,570 in electricity to mine $15 of Lithium.>And that’s assuming 100% pump efficiency and zero friction.>Aqueducts>implies lifting water uphill with open channels>Aqueducts go *down*, brainlet. Unless you plan to dig a tunnel through the base of the mountain (billions of dollars), you have to pump it over the top.You are describing a Pumped Hydro Storage system that is incompetent at storage, terrible at mining, and produces dirty water.
>>16886303(cont)>when talking about energy?*energy efficiency>according to google, plastic (HDPE, PVC, ...) piping has a much lower friction factor than steelsource: https://personalpages.manchester.ac.uk/staff/david.d.apsley/lectures/hydraulics2/l2.pdffrom what I'm reading, a lot of your criticisms could be addressed by considering efficient designs from the start. for example, many papers say oil pipelines or water distribution systems can be made more efficient by calculating efficient changes to their current designs, switching from gas-fired turbines to electric motors, etc. but I have no idea how much efficient could this be madeI guess a lot of that has to do with infrastructure, though, and that might make everything more expensive.>>16886319>You want to heat the ocean to make it lighter?>>implies lifting water uphill with open channels>>Aqueducts go *down*, brainlet.>>To get 1 KG OF LITHIUM ($15 value), you pump 5,800 TONS of water up 2000m.holy fuck, you are the one calling me retarded?I doubt you are the same anon. you either lack imagination or are trolling now lmaobut, in any case, you obiously missed the point: is not about making it economical, it's about getting more water, and recovering some money/energy in the process. and if you are already pumping, storing, and getting salt and minerals from the seawater, might as well take advantage of it.
>>16886327>heat the water to reduce its density>you either lack imaginationMy brother in Christ, thermodynamics is not a creative writing exercise.Let's look at your "imagination" vs. Physics:1. Heating: Water density at 20°C is ~998 kg/m3. At 50°C, it's ~988 kg/m3. You save 1% on lifting mass.• Energy to lift 1kg up 2km: ~19.6 kJ.• Energy to heat 1kg by 30°C: J = 125.5 kJ.• You are spending 600% more energy to save 1% on pumping. This is the single dumbest engineering proposal I have read on this board.2. "Efficient Design" Cope: "Just make it efficient bro." You can't optimize gravity. The theoretical minimum energy to lift mass is fixed. No amount of shiny plastic pipes or electric motors changes .3. The "Bonus": You are spending $1,500 in electricity to recover $15 of Lithium. That is not a "bonus." That is bankruptcy. You are literally burning money to move salt around.You aren't solving a drought; you're building the world's most expensive water slide.Go apologize to your physics teacher.
>>16886332anon, I know how to calculate energy usage. but YOU said this system wouldn't be able to recover energy because of friction. now that I showed you a tiny bit of interest in actually discussing things, you switch arguments.fucking kekbtw, you'd be lifting water during summer using solar energy and recovering whatever you can during winter. do you not realize that you can also get heat for free from the solar panels?you obviously didn't read shit of what I wrote in the fucking OP, because you don't actually care. you just want to be contrarian.
>>16886342>Switched argumentsNo, I'm piling them on because your fractal wrongness has layers.Let's talk Efficiency (Round Trip):1. Up: Pay Potential Energy (mgh) + Friction.2. Down: Recover (mgh) - Friction - Turbine Loss.Standard Pumped Hydro (vertical lift) is ~80% efficient. Your 100-mile horizontal slip-n-slide? You'd be lucky to hit 40%. You are wasting most of your "free" solar just fighting drag."Free Heat" from Panels:>heat water to pump it easier>freeze it in winterYou want to pump warm water into a reservoir... so it stays warm... right before you try to FREEZE it?Water has high thermal mass. If you heat that lake to 40°C in summer, you just delayed your winter freezing by two months. You are sabotaging your own critical path to save 0.5% on density.You aren't a visionary; you're a guy who thinks he can beat the casino because he found a coupon for the buffet.Post the P&ID or lurk more.
>>16886350> 40°Cagain, I'm not sure if you are trolling anymore. you are taking cold (so around 4°C) water from the bottom of the sea. you do know that water is denser at that temperature, right? heating it a bit would make it less dense. no need to heat it that much to get a little bit of efficiency. and you are taking it at summer anyway, so you could take advantage of the heat.>so it stays warmno? what is a radiator? >right before you try to FREEZE it?anon... 6 months is a lot of time, more than enough to reduce its temperature. you know, there are lakes in mountains, and their temperatures vary enough to produce ice during winter while being completely liquid in summer.>You are wasting most of your "free" solar just fighting dragthen maybe find other ways to reuse that heat to make the system more efficient?anyway, that was just an idea. no need to get mad.thanks for the criticism, I guess. but I'm not sure why you got so mad at me. it might be a retarded idea, but again, you seem to have missed the point. even at 40% recovery, if you could produce a lot of fresh water, it could be useful in some places.I guess there could be variants to this idea. since your main criticism is the energy lost to friction due to length of the pipe, you could instead find ways to make it shorter, like, finding hilly places that are closer to the coast (my country has many), or, instead of moving the water during summer, you could lift it to artificial ponds whenever there is sun during winter, similarly to pumped hydro setups. google says pumped hydro systems recover about 70-90% of the energy... that's good enough.main problem here is that these places might not get cold enough, precisely because of how close they are to the sea...
>>16885724>1 GW in solar panels can move a lot of water.Why can't I just boil the water with that 1GW?>inb4 it would be more efficientWhy do I care about efficiency when solar energy is free.
>>16886416I mean, you could. literally no one is stopping you.and if you can get 1GW of electricity, you could probably get ~5GW of heat, since solar panels are ~21% efficient.
