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View Diary: Shocking drought data from NASA (382 comments)

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  •  That is only if you boil the water in an open pot (4+ / 0-)

    and collect the steam.  There is a trick though - the steam gives up as much energy when it cools and condenses as it absorbed when it evaporated.  If you recycle the heat from the steam to warm the incoming water, the energy requirement drops - your condensor is simply a heat-exchanger cooling the steam and heating the incoming water.  Once yo get this running, the only heat it needs is whatever is required to cover the energy loss - which is simply the difference in temperature of the incoming dirty water and the outgoing clean water, plus any radiation losses.

    "Wrong, Do it again!" "If you don't learn to compete, you can't have any pudding. How can you have any pudding if you don't learn to compete?" "You! Yes, you occupying the bikesheds, stand still laddy!"

    by ban48 on Thu Jul 24, 2014 at 05:24:47 PM PDT

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    •  I did forget - desalination adds an extra energy (3+ / 0-)
      Recommended by:
      JerryNA, FarWestGirl, 207wickedgood

      loss.  It takes more energy to boil salt water than to boil fresh water - hence less energy can be recovered from the steam.  The extra energy is required to break the water molecules from the salt molecules.  This is required in any desalination process though.

      "Wrong, Do it again!" "If you don't learn to compete, you can't have any pudding. How can you have any pudding if you don't learn to compete?" "You! Yes, you occupying the bikesheds, stand still laddy!"

      by ban48 on Thu Jul 24, 2014 at 05:32:48 PM PDT

      [ Parent ]

      •  Sound like an interesting engineering problem. (2+ / 0-)
        Recommended by:
        missississy, FarWestGirl

        You need to constantly pump in 'fresh' undesalinated  (salinated?)  water in order to keep the salt concentration from increasing,and thus increasing the boiling temperature, but not at too high a rate, as you need to increase the contact time with the condensing output as  much as possible in order to conserve as much heat energy as possible. What  would be the optimal flow-through time?

        Quick, somebody send Randall Munroe a What-if!

        •  Yup, you'd want to do something like that, also (0+ / 0-)

          to keep crud from building up in the system.  So you'd want to slowly drain off the bottom of the 'boil pot' and run both it and the steam through heat-exchangers to heat the incoming water.

          "Wrong, Do it again!" "If you don't learn to compete, you can't have any pudding. How can you have any pudding if you don't learn to compete?" "You! Yes, you occupying the bikesheds, stand still laddy!"

          by ban48 on Fri Jul 25, 2014 at 01:52:47 PM PDT

          [ Parent ]

      •  Now, I wonder ---- what about a solar still (1+ / 0-)
        Recommended by:
        FarWestGirl

        to evap the saltwater using the plentiful energy of the sun?

        LBJ, Van Cliburn, Ike, Wendy Davis, Lady Bird, Ann Richards, Barbara Jordan, Molly Ivins, Sully Sullenburger, Drew Brees: Texas is NO Bush League!

        by BlackSheep1 on Thu Jul 24, 2014 at 10:02:16 PM PDT

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        •  I think these are part of life raft equipment (2+ / 0-)
          Recommended by:
          FarWestGirl, BlackSheep1

          Simple plastic sheet dome over a pan. The condensate flows down the dome to a collection vessel.

          Real plastic here; none of that new synthetic stuff made from chicken feathers. By the morning of 9/12/2001 the people of NYC had won the War on Terror.

          by triplepoint on Fri Jul 25, 2014 at 01:10:12 AM PDT

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    •  use separated loops (2+ / 0-)
      Recommended by:
      DrSUSE, FarWestGirl

      Any thermal plant will have a certain amount of heat it needs to lose to maintain coolant inflow at a certain temperature. That will be based on the phase change temperature and the designed operating pressure. Separate loops would probably be needed because I doubt anyone would want to use saline for the primary coolant loop due to corrosion issues. Use a second or third loop with saline and you can probably use the waste heat as process heat for a bit of desalination.

      -We need Healthcare Reform... but i'm selfish, I Need Healthcare reform-

      by JPax on Thu Jul 24, 2014 at 09:57:56 PM PDT

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