The only advantage is the disposition of the salt - making ice thicker at the bottom ensures that the salt stays in the water, not the ice. As has been pointed out before, we don't know what happens with the salt if you flood the ice from the top, nor whether higher-salinity ice creates a problem by melting earlier.
However, given that the oil industry seems to use this approach regularly, it seems like it ought to be relatively straightforward for the right person to actually collect some data rather than simply trading hypotheses. (The right person almost certainly isn't me, much though I'd love the excuse to head up to the Beaufort sea.) -----Original Message----- From: geoengineering@googlegroups.com [mailto:geoengineering@googlegroups.com] On Behalf Of Andrew Lockley Sent: Wednesday, January 15, 2014 4:24 PM To: Ronal Larson Cc: Keith Henson; Geoengineering; John Nissen; Peter Flynn; RAU greg Subject: Re: [geo] Making ice (change of thread title) Personally, I can't see these thermal diodes being at all practical. Far cheaper and simpler to just break up the ice, or pump water on top of it. The maths is pretty simple. The thermal diode can only be at a temperature of the water, at a maximum. It's heat transfer is a function of the surface area exposed to the air. This heat exchanger is a manufactured item, and thus expensive, with a small surface area. Flooding the ice with seawater gives a far higher surface area and thus far higher heat transfer. A On 15 January 2014 21:58, Ronal W. Larson <rongretlar...@comcast.net> wrote: > Keith: > I go through line by line - but deleting as much as I can. Mine all in > bold caps. > > > On Jan 15, 2014, at 10:28 AM, Keith Henson <hkeithhen...@gmail.com> wrote: > > On Tue, Jan 14, 2014 at 9:50 PM, Ronal W. Larson > <rongretlar...@comcast.net> wrote: > > Keith: > > Again thanks > > Re- being able to make thicker ice in the Arctic - from the bottom, not the > top. > > > I don't see it being the bottom. The ocean is thousands of feet deep > and I can't see making these thing more than a 100 feet, say 30 meters > long. > > [RWL1: I am projecting only adding like a meter to ice that is already > (hypothetically) a meter thick - so it can get through a September > area/extent minimum. Most Arctic ice forms from the bottom - only a little > from falling snow. Asking Peter for more input here on best thickness > change projections. > I project something that can be thrown from a helicopter wherever an > opening crack appears. Only operates when there is already a little ice. > This might work also to extend the area of Antarctic ice, keeping the > area/extent up for more months. By not deploying in some areas, you can > keep some transport lanes open. > > > > <Snip two> > > > The Antarctic case seems a bit harder - with a need for stiffer, stronger > pipe. Any reason the floating Arctic unit couldn't be made of a thinner > plastic and get closer to a $1 or so per foot (with a total of (?) less than > 10 feet?) > > > I doubt it. The floating versions have to stand a fair amount of > pressure just from the water pressure on them. But no matter the > cost, who is going to pay for them? Polar bears? > > [RWL2: I don't get the "pressure" issue. These can be relatively > thick walled plastic, and the shape is appropriate for compression forces. > I don't see much shear for floating ice a few meters thick. Again - Peter? > > > I hope you can find your earlier cost calculations. I think we have a > chicken and egg situation. The person finding the money (John Nissen?) will > have to have some cost calculations. > > > It would take a few days with a spreadsheet. I think I figured them > out years ago on the basis of a 5 year ball of ice several hundred > feet in diameter. But that's just the start of the complexity. The > wind blows the ice around and in spite if being in the middle of some > very hard ice, the heat pipes are going to get broken on a regular > basis. > > Make a case that someone would pay for it and I can run off the calculation. > > Then again, you can probably ignore the hardware cost since the legal > expenses are likely to dominate. > > [RWL3: We have very different geometries in mind - as above, I am > hoping for diameters like yours , but only a thickness like a meter. I ask > Peter Flynn for support on whether this might seem possible. Re breakage, > that would be the purpose of some early testing. > I'm afraid in this game there are no design funds - all open source. > > <again snip a bit> > > > It would be great if anyone could make a synthetic > char, starting with CO2. > > > That's been done decades ago. NASA had a project that would reduce > CO2 to carbon flakes and oxygen. It's also an energy hog, not as bad > as synthetic wax or oil, but you can't pump char. > > [RWL4: I don't want carbon, I want something that has big interior > surface area and very low density; charcoal. I have not looked into the > NASA literature on recycling CO2 and will. But hope someone can comment. I > doubt it will lead to a structure that looks like charcoal (needed to get > high CEC - cation exchange capacity and other desirable features that cost > nothing with char.). > > > I once read that no-one knows how to make a > synthetic volcanic lava (maybe no longer true, anyone? It would make a > great material for simple char-making carbon-negative stoves.) > > > Melted rock is easy. But I don't get a "carbon-negative stove." > Plants *and* a char process together are carbon negative, sort of. > The carbon returns to the air in less than geological time. > > [RWL5. Sorry, I didn't explain enough on the lava question. I am > looking for a very light weight porous but very strong, heat resistive > material. I have seen an ideal product that is "sawn"commercially out of a > solid lava mountain in Nicaragua. Melted rock is not what is needed - too > dense. > Any char-making stove (look up the word "TLUD") can be carbon negative > if the char is placed in soil (then changing name to "biochar"). Yes > lifetime is an issue, but char is used for anthropological dating going back > millions of years. We will be happy with a commonly used value of 1000 - > and can live with less. > > > Your proposed diode will operate with the "hot" side always around 0 oC, and > the cold side dependent on the nighttime air temperature that (not looking > anything up) might average -30 or -40 oC. > > > No, the hot end goes down to the lowest temperature of the air, less > relatively minor heat leakage. > > [RWL6: Not understanding. Ask for Peter Flynn's help again. If you > are boiling a fluid at the bottom the thermal energy movement is upward. > Maybe we are not disagreeing - but the bottom "hot end" in a heat pipe sense > has to be a good bit warmer than the atmospheric above ground (condensing) > temperature to have heat transfer. > > <snip remainder to help keep lengths down> > > -- > You received this message because you are subscribed to the Google Groups > "geoengineering" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to geoengineering+unsubscr...@googlegroups.com. > To post to this group, send email to geoengineering@googlegroups.com. > Visit this group at http://groups.google.com/group/geoengineering. > For more options, visit https://groups.google.com/groups/opt_out. -- You received this message because you are subscribed to the Google Groups "geoengineering" group. 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