Abstract:
An apparatus and method for the distillation of ocean and brackish water that includes a means for using the ambient temperatures of seawater and air to continually transfer the heat energy, from the outer perimeters of the system, back into the, centrally located, evaporation chamber and insulation for preventing heat from escaping to the atmosphere. The insulation comprises a first and second wall surrounding the basic assemblies of a desalination system in which the space between the first and second wall is under low partial vacuum and is partially filled with an insulation material for structural support. The system provides a feed through means that prevent heat transfer through the structural connections between the first and second walls. The system provides an evaporation system for flash evaporation by atomizing the input contaminated water, preheated by the heat of condensation into very small liquid droplets, which are then sprayed into a stream of hot dry air. The liquid rapidly evaporates leaving behind hot dry solids that is recaptured and used to preheat the input contaminated water.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a continuation-in-part application of U.S. patent application Ser. No. 12/902,011, filed Oct. 11, 2010, entitled “Large Scale insulated Desalination System,” which application is incorporated here in its entirety by this reference. 
     
    
     BACKGROUND 
       [0002]    The present invention relates primarily to methods of improving the efficiency, reducing environmental issues, and operational and capital costs, of desalination systems. More particularly, to desalination systems that distill brackish or ocean water. 
         [0003]    Fresh water is a scant 2.5% of the total global water supply and 69% of that is represented by permanent snow and glaciers. The remaining 97.5% is saltwater. Since 1940, the amount of fresh water used by humanity has roughly quadrupled as the world population doubled. Given the finite nature of the earth&#39;s fresh water resources, such a quadrupling of worldwide water use probably cannot occur again. In many of the regions where the world population is growing most rapidly, the needed fresh water is not available. Desalination of seawater represents the best source of fresh water to satisfy future requirements. 
         [0004]    However, present day desalination systems are energy intensive. For example, the newly constructed system in Carlsbad, Calif. is said to be the most energy efficient of any large scale desalination system in the USA at 3.6 kilowatts per cubic meter of water. It also desalinates only fifty percent of intake water, returning the remaining concentrated brine to the ocean. Returning concentrated brine solution to the ocean presents a continually escalating environmental hazard to the ocean ecosystem. 
         [0005]    For desalination to be the source of fresh water to meet future requirements, it must be cost competitive with ground water sources and environmentally friendly. 
         [0006]    The true cost of household fresh water is difficult to assess due to government subsidies, transfer cost and variations in local energy and labor cost. However, it is estimated that energy requirements for desalination should be in the range of about 2 to 2.5 kilowatts per cubic meter of fresh water to be competitive. 
         [0007]    Another environmental issue involves seawater intakes that can only be addressed in connection with site location of the desalination system. However, there are intake methods such as subsurface, sand filters, subterranean, and beach wells that can solve most environment intake problems. 
         [0008]    Throughout the world today, all desalination facilities combined produce about 38 million cubic meters (approx. 10 billion gallons) of desalinated water per day. These facilities basically utilize two technologies, membrane filter processes and thermal distillation processes. Of these processes, reverse osmosis (membrane filter process) and multi-stage flash distillation (thermal distillation process), make up and share about 80% of the world market. 
         [0009]    Reverse osmosis uses high pressure pumps to force fresh water through a semi-permeable membrane, leaving the dissolved solids behind. This process requires seawater pretreatment, an electrical power source, chemical post-treatment and annual membrane replacement. 
         [0010]    Multi-stage flash (MSF) involves introducing heated seawater into multiple, reduced pressure chambers that cause a portion of the water to instantly flash (boil) into water vapor. The vapor is then condensed into distilled water. This process requires an energy source for heating the seawater as well as control functions. 
         [0011]    Both technologies are energy intensive, and both convert about 50% of the input seawater into fresh drinkable water, discharging the remaining brine solution back into the ocean, which results in an ever increasing environmental problem. 
         [0012]    The past decade has seen a huge increase in research and development in desalination projects around the world utilizing improved technologies, resulting in improved efficiency and reduced capital costs, such as low temperature flash desalination. Numerous patents have been granted disclosing designs that improve efficiency. A large number of these patents involve the “flash desalination” of water at low, near ambient temperatures in an effort to reduce energy requirements. Although seawater can be evaporated at low temperatures by decreasing pressure (partial vacuum), the decreasing temperature results in an exponential decrease in the Vapor Saturation Density. Therefore, large quantities of vapor must be transferred to recover significant quantities of distilled liquid, which places much higher energy and costs requirements upon the system. 
         [0013]    For example, at 40° C. (104° F.), saturated vapor density is 51.1 grams per cubic meter (0.00319 pounds per cubic feet). At 110° C. (230° F.), saturated vapor density is 850 grams per cubic meter (0.05306 pounds per cubic feet). The result is that a system that is to produce 100 cubic meters (26,417 gal) of fresh water per day at a temperature of 40° C. must transfer vapor at a rate of more than 1359 cubic meters per min, whereas at 110° C. it would only need to transfer 81.7 cubic meters per min. 
         [0014]    Despite the inventions, research, developments and improvements, present day seawater desalination processes continue to be an intensive fossil energy consumer that escalates desalination cost from to 5 times greater than ground water supplies. 
         [0015]    The desalination industry has publicized that the minimum energy requirement to desalinate 3.5% seawater is 860 watts per cubic meter. A true statement, but somewhat misleading in that the process does require 860 watts per cubic meter to remove the dissolved solids. However, desalination is a reversible process; therefore, the energy used for removing the solids can, theoretically, be recovered. 
         [0016]    In a thermal desalination system the “heat of vaporization” can be recovered in the condensation stage, referred to as the “heat of condensation.” 
         [0017]    The first law of thermodynamics states that the total energy of an isolated system is constant; energy can be transformed from one form to another, but cannot he created or destroyed. 
         [0018]    For a thermal process to be effective the system must be isolated (insulated) so that minimum heat energy escapes the system. The thermal process does not require energy form changes and can extract dry solids from seawater. 
         [0019]    For a filtration process to recover and reuse the energy would require transforming from one form of energy to another (e.g., electrical to pressure) resulting in high entropy. The process cannot extract dry solids from seawater. 
         [0020]    Therefore, there is still a need to create an efficient desalination that results in operational cost equal to, or less than, conventional ground water supplies. 
       SUMMARY OF THE INVENTION 
       [0021]    In one embodiment, the present invention is directed towards a desalination system for substantially increasing the efficiency of the distillation of ocean and brackish water by continuously reusing heat energy to reduce the overall energy requirements, comprised of basic assemblies, including an evaporation chamber, a vapor transfer assembly, and a condensing chamber, that are surrounded by a, double wall assembly comprised of a first and second wall, wherein the space between the first and second wall is placed under low partial vacuum to maintain very low conductive and convection heat loss. An external water heater source feeds heated input sea water into the evaporation chamber through a plurality of spray nozzles, which transforms the sea water into droplet-mist that flash vaporize into a density-saturated vapor. The density-saturated vapor is drawn into the condenser by a vacuum pump assembly. The solids that remain from the flash vaporization fall to the bottom of the evaporation chamber. Any droplet-mist that does not vaporize is prevented from entering the vapor transfer assembly by a demister. The density-saturated vapor is discharged through the vacuum pump assembly and is forced into the condensing chamber located below the vacuum pump assembly. The condenser is then continuously cooled by intake sea water distributed by a ratio valve through an intake channel into a heat-exchanger port. This condenses the liquid-vapor into pure liquid distilled water. Concurrently, the intake sea water is heated by its contact with the heat exchanger. The heated intake sea water is then transferred to the external water heater source through a vacuum insulated channel to be fed back into the evaporation chamber. 
         [0022]    The ratio valve also distributes intake sea water to the bottom of be evaporation chamber to cool the solids that fall and collect at the bottom. This is accomplished by distributing the intake sea water through a first chamber port into cooling coils to cool the solids. The intake sea water is heated in the process, and is transferred back to the external water heater source through a vacuum insulated channel. The preheated intake sea water is then fed into the evaporation chamber. 
         [0023]    In another embodiment, the desalination system similarly uses a thermal process that converts saltwater, such as seawater or brackish water, into fresh distilled water. The system introduces methods for continually removing the dissolved solid byproducts that may be processed as sea-salt. The output is 100% potable and dry solids, with zero liquid discharge. This feature eliminates the environmental problem of discharging waste brine solution back into the ocean. 
         [0024]    The desalination system efficiently vaporizes saltwater, thereby extracting the dry solids from the water and condensing the water vapor back into liquid form to create distilled water by reusing retained heat energy multiple times. The only energy input, after startup stabilization, is the energy required to compensate for the small heat energy loss to the atmosphere, through a vacuum insulation double wall, the drive motor of the vapor transfer assembly, and instrumentation. 
         [0025]    The desalination system recovers the heat energy used in the vaporization process. Heat loss in the distillation system is essentially eliminated, reducing energy requirements to approximately 1.2 kWh/cubic meter (264 gallons) of fresh water, far below energy requirements used in current technologies. 
         [0026]    Heat energy used to evaporate water (heat of vaporization) is recovered in the condensing phase (heat of condensation) and used to preheat the incoming seawater. This process is continuously repeated reusing the heat energy multiple times. The process requires that very little heat energy, above the input seawater ambient temperature, be allowed to exit the system. 
         [0027]    In addition, the desalination system is designed with components that minimize the total outside system surface area so as to minimize heat loss to the atmosphere. Also, the system employs vacuum insulation via a double-wall assembly that surrounds the components of the desalination system to prevent heat energy, greater than a few degrees above ambient seawater temperature, from exiting the system. Insulation is provided by a deep partial vacuum created between the first and second walls of the double-wall assembly. 
         [0028]    The system may be designed with spray nozzles that transform the fluid water into a fine mist of water droplets with droplet sizes below fifty microns. Droplet surface area and temperature are key issues in the vaporization stage. Evaporation occurs first at the liquid surface causing the remaining liquid to be more concentrated, which increases the boiling point and energy required to vaporize the remaining liquid. Therefore, it is important to increase surface area as much as possible. 
         [0029]    Using spray nozzles to break the liquid into small droplets greatly increases the surface area. The large surface area decreases the time and energy for evaporation. 
         [0030]    For example, a one-inch diameter (volume=0.523 cubic inches) drop of water has a surface area of 3.14 square inches. 
         [0031]    If the same volume is parted into 10 micron (3.937E-04 inch) diameter droplets (volume=3.19E-11 cubic inch), the total number of droplets would be over 16 billion with a total liquid surface area of 7,980 square inches. 
         [0032]    The condenser may be a specially designed spiral heat exchanger that uses the inside surface of the second wall of the double-wall assembly as part of the outside spiral of the condenser. Intake seawater ambient temperature is introduced to the outside spiral that lowers the temperature of the vacuum insulation second wall and transfers the heat energy back into a vaporizing chamber. This arrangement reduces the temperature of the vacuum insulated second wall, and the energy that would normally escape to the atmosphere through the vacuum insulation. 
         [0033]    The primary objective of the present invention is to provide a means of increasing the overall efficiency of large scale desalination systems by significantly reducing the energy input requirement, and make desalination affordable. Another object of the invention is to provide a means for using the ambient temperatures of seawater and air to continually transfer 
         [0034]    The heat energy, from the outer perimeters of the system, back into the, centrally located, evaporation chamber. Another object of the invention is to provide a means of using evacuated space (partial vacuum) insulation that prevents heat from escaping into the atmosphere. The invention also includes means for reusing the heat energy repeatedly to preheat the incoming saltwater. The invention also provides a method for evaporating the heated saltwater into a density-saturated vapor. It also provides a means for condensing the vapor into fresh distilled water and capturing and re-using the heat-of-condensation to preheat the input saltwater. A further object of the invention is to provide means for separating the dissolved solids from the liquid water and still further means for continually removing the solids from the system without interruption. A further object of the invention is to provide means for removing the heat energy from the hot solids and reusing it to preheat the air flow as it enters the air heater, which provides heat to vaporize the droplet mist as it falls within the evaporation chamber. A further object of the invention is to provide means for eliminating the heat loss through the structural feed through of the vacuum insulated double wall. 
         [0035]    Additional objects of the present invention will become better understood with reference to the description and claims. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0036]      FIG. 1  is a diagrammatic representation of an elevation view of a cross-section of an embodiment of a desalination system incorporating features of the present invention. 
           [0037]      FIG. 2  is a graphic view of a saturated vapor pressure curve for water. 
           [0038]      FIG. 3  is a diagrammatic representation of a solar collector incorporating features of the present invention. 
           [0039]      FIG. 4  is a diagrammatic representation of an elevation view of a cross-section of a second embodiment of the desalination system. 
           [0040]      FIG. 4A  is a perspective view of a cross section of the second embodiment. 
           [0041]      FIG. 5  is a perspective view of a feed-through assembly of the second embodiment. 
           [0042]      FIG. 5A  is a plan view of a feed-through assembly with the top and bottom covers removed. 
           [0043]      FIG. 5B  is a perspective view of a cross section of a feed-through assembly. 
           [0044]      FIG. 6  is a perspective view of a square toroid shaped heater. 
           [0045]      FIG. 7  is a perspective view of a finned funnel assembly. 
           [0046]      FIG. 8  is a perspective view of a condenser assembly of the second embodiment. 
           [0047]      FIG. 8A  is a perspective view of a cross section of the condenser assembly. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0048]    The detailed description set forth below in connection with the appended drawings is intended as a description of presently-preferred embodiments of the invention and is not intended to represent the only forms in which the present invention may be constructed or utilized. The description sets forth the functions and the sequence of steps for constructing and operating the invention in connection with the illustrated embodiment. It is to be understood, however, that the same or equivalent functions and sequences may be accomplished by different embodiments that are also intended to be encompassed within the spirit and scope of the invention. 
         [0049]    Referring to the drawings,  FIG. 1  is a representative view of an embodiment of the desalination system  10  showing all of the basic assemblies and plumbing surrounded by a first wall  20   a  and secondary wall  20   b  of a double wall. The space  25  between the first wall  20   a  and the secondary wall  20   b  is under low partial vacuum, between 0.001 and 1 Torr (0.1333 to 133.3 Pascal), thereby maintaining very low conductive and convection heat loss. The space  25  can be partially or totally filled with an insulation material  26  for structural support. Perlite is used for the structural support in the preferred embodiments as it exhibits a thermal conductivity of 0.031 W/m*K that improves to 0.00137 W/m*K under partial vacuum. 
         [0050]    Still referring to  FIG. 1 , the assemblies include an evaporation chamber  1  that houses a plurality of spray nozzles  2  being fed heated input sea water  3  from an external water heater source  4 . The preferred external water heater source  4  is a solar collector field (see  FIG. 3 ), although fossil fuel energy source can be used especially in poor solar areas. The plurality of spray nozzles  2  are designed to provide fine droplet-mist  5  that flash vaporize into a density-saturated vapor  6 . The evaporation chamber  1  is under partial vacuum generated by a vacuum pump-assembly  12 . The vacuum pump assembly  12  is designed to insure that the pressure in the evaporation chamber  1  is well below the saturation vapor pressure over the range of input water  3  temperature. As the droplet-mist  5  vaporize, the remaining solids  7 , being heavier than the surrounding density-saturated vapor  6 , fall and collect at the bottom  8  of the evaporation chamber  1 . 
         [0051]    Referring to  FIG. 2 ,  FIG. 2  is a graphical view of the “Vapor Pressure Curve of Water” showing vapor pressure and the corresponding temperature at which water vapor and liquid can coexist in equilibrium. At any given temperature on the curve, if the pressure is increased, the water can exist only as liquid. If the pressure is decreased, the water can exist only as vapor. 
         [0052]    Now referring back to  FIG. 1 , so long as the temperature of the fine droplet-mist  5  is sufficiently high and the pressure in the evaporation chamber  1  is sufficiently low, the fine droplet-mist  5  will become a density-saturated vapor  6  leaving all remaining solids  7  (e.g., previously dissolved salt) behind. Directly above the plurality of spray nozzles  2  is the demister  9  which prevents the fine droplet-mist  5  from entering the vapor transfer assembly  11 . The vapor transfer assembly  11  connects the top of the evaporation chamber  1  to the vacuum pump assembly  12  and provides a means for the density-saturated vapor  6  to transfer between the evaporation chamber  1  and the vacuum pump assembly  12 . The density-saturated vapor  6  is drawn through the demister  9  by the vacuum pump assembly  12 . A condensing chamber  13  is mounted below the vacuum pump assembly  12 . The discharge output of the vacuum pump assembly  12  provides a pressure increase within the condensing chamber  13 . The increased pressure forces the density-saturated vapor  6  into the state of vapor-liquid  14  and to move into a heat exchanger  15 . The heat-exchanger  15  is continually cooled by the intake sea water (sea water input)  16  that is distributed by a ratio valve  17  through an intake channel  18  into a heat-exchanger port  19 . The liquid-vapor  14  is cooled within the heat-exchanger  15  and further condenses into pure liquid water  21 . The pure liquid water  21  exits the heat exchanger  15  at a temperature near the intake sea water  16  temperature through a condensing chamber port  22 . The intake sea water  16  that s the heat-exchanger  15  through the ratio valve  17 , intake channel  18 , and heat-exchanger port  19  is heated by the heat-of-condensation of vapor-liquid  14  and is transferred from the heat-exchanger exit  23  through a vacuum insulated channel  24  as preheated input seawater to the external water heater source  4  (solar collector field). Intake sea water  16  is also distributed by the ratio valve  17  through a first bottom chamber port  27  into cooling coils  28  and cools the remaining solids  7  that collect at the bottom  8  of the evaporation chamber. As the intake sea water  16  is heated by the remaining solids  7 , it exists the cooling coils  28  through a second bottom chamber port  29  and is transferred through a vacuum insulated channel  31  as preheated input sea water  33  to the external water heater source  4 . The remaining solids  7  are periodically or continuously removed from the bottom  8  of the evaporation chamber through an outlet  30  by an auger  32 . The ratio valve  17  adjusts the intake sea water  16  flow rate through the heat-exchanger and cooling coils  28  to insure minimum heat loss and maximum heat recovery. The bottom  8  of the evaporation chamber, including the auger  32 , may be modified or changed to other methods of removing remaining solids  7  depending on the quality and filtering method of the intake sea water  16 . If the sea water is pumped from beach wells or sub-surface intakes that remove all un-dissolved solids, the remaining solids  7  may be used for sea salt. The beach wells or sub-surface intakes will also greatly reduce the intake of solvents that have boiling points lower than water that could potentially contaminate the distilled water. In the preferred embodiment, the heat exchanger  15  is a Plate Heat Exchanger (PHE) as opposed to other types for overall performance and maintenance. The type of vacuum pump assembly  12  is also optional, depending on the size (cubic meters per day) of the overall system and where it is to be located. Flash evaporation is used in the preferred embodiment; however, it is apparent that almost any type of heat base desalination could be greatly improved by using vacuum insulation. 
         [0053]    The following description describes another embodiment of the present invention. Components that are similarly named or perform similar functions may be interchangeable and share similar features in both embodiments regardless of the reference number designations. With references to  FIG. 4 , the desalination system  100  of the present invention substantially increases the efficiency of the distillation of contaminated water, such as ocean and brackish water, by continuously reusing heat energy to reduce the overall energy requirements. The desalination system  100  comprises a double-wall assembly  101  housing an evaporation chamber  500  a vapor transfer assembly  400 , and a condenser  300  (also referred to as condensing chamber). Saltwater is taken through the double-wall assembly  101  where it is heated and vaporized in the evaporation chamber  500 , and transferred to the condenser  300  by the vapor transfer assembly  400 , where the vapor condenses into distilled water, leaving the extracted dry solids  902  that continue to fall within the evaporation chamber  500 . 
         [0054]    The double-wall assembly  101  comprises a first (outer) wall  102  and a second (inner) wall  103  that is surrounded by the first wall  102 , thereby defining a space  104  between the first and second walls  102 ,  103 . The space  104  may be under low partial vacuum to maintain very low conductive and convection heat energy loss. The first wall  102  is exposed to the environment. The second wall  103  may be substantially coextensive with the first wall  102  to create the space  104  in between the first and second walls  102 ,  103 . 
         [0055]    Preferably, a deep partial vacuum is provided within the space  104  between the first wall  102  and second wall  103 . The double-wall assembly  101  surrounds the components of the desalination system  100 . In some embodiments, the space  104  between the first and second walls  102 ,  103  may include an insulator  105 . Preferably, the insulator  105  is a structural insulation. For clarity, the insulator  105  is shown in a small portion of the space  104 . However, the insulator  105  can occupy up to the entire space  104 . In the preferred embodiment, perlite is used for the insulator  105  as it exhibits a thermal conductivity of approximately 0.031 W/m*K that improves to 0.00137 W/m*K under low partial vacuum, and may provide structural support. 
         [0056]    The first wall  102  and the second wall  103  of the double wall  101  are connected for structural support that also provides an opening  106 . 
         [0057]    A common problem with vacuum insulation is the thermally conductive path that is created by the necessary structural support connecting the double walls that maintain positioning of the two walls relative to each other, and to provide a passageway for accessibility to the internal cavity of the double wall. 
         [0058]    The double wall assembly  101  has only one opening  106  at one end of the system  100 , thereby creating a passageway from the outside of the system  100  to the internal cavity defined by the internal surface of the second wall  103 . Preferably, the opening  106  is created at the bottom end of the system  100 . 
         [0059]    Refer to  FIG. 4 ,  FIGS. 5, and 5A . To reduce thermal conductive and convective heat loss, through the opening  106  is a feed-through assembly  200  that allows saltwater to enter the system and distilled water to be collected and transferred out of the system. In some embodiments, as shown in  FIG. 5A , the feed-through assembly  200  may comprise a spiral type heat exchanger. The outer cylinder wall  201  may comprise an intake port  202  to take in the saltwater, and an exit port  203  in fluid connection with the intake port  202  to deliver the saltwater into the condenser assembly  300  and a receiver port  204  to receive distilled water that has been processed by the system  100 , and a distilled water outlet port  205  operatively connected to the receiver port  204  to return distilled water for collection. The distilled water may be at or near ambient temperatures. An inner cylinder, central channel  206 , may define a passageway for introducing ambient air  907  into evaporation chamber  500 . The central channel  206  may also be used as an exit port for the dry solid transfer assembly  903  to remove dry solids from the evaporation chamber  500 , and route wiring and cable into the system  100 , without excessive heat loss. 
         [0060]    Refer to  FIG. 4 ,  FIG. 5A . As the feed-through assembly  200  is mounted within the opening  106  of the double wall assembly  101 , the outer cylinder wall  201  of the feed-through assembly  200  makes contact with the opening  106  wall of the double wall assembly  101 . Ambient temperature seawater flows through intake port  202  of the feed-through assembly  200  into the outer first spiral of channel  207  that is in direct contact with the outer wall  201 . The outer wall  201  is in contact with the structural wall  106  of the double wall assembly  101 . The heat energy above ambient temperature that normally flows through opening  106  of the double wall assembly  101 , is transferred to the seawater. The second spiral channel  208  and the first spiral channel  207  are thermally connected by a single spiral plate  209 . Distilled water from the condenser  300  flows, though port  204 , into the inner second spiral channel  208  of the feed-through-assembly  200 . The heat energy above ambient temperature that remains from the condensing process is transferred to the seawater and back into the condenser assembly  300 . Surrounding the funnel exit passageway (inner channel  206 ) is an open passageway for ambient temperature air, that is drawn into the system by the vapor transfer assembly  400  that also provides additional heat exchange for any remaining heat, from the dry solids  908 , and transfers it back into the internal system. 
         [0061]    Refer to  FIG. 4 ,  FIG. 5  and  FIG. 8 . Seawater, under pressure, flows through the intake port  202  and exit port  203  of feed-through assembly  200  into the intake port  301  of condenser  300 . The spiral condenser  300  surrounds the evaporation chamber  500 . The outer wall  305  of the condenser  300  is in direct contact with the inside of the second wall  103  of the vacuum insulated double wall  101 . The input seawater adsorbs heat, from the inside second wall  103 , of the double wall assembly  101  and transfers it into the evaporation chamber  500 , that reduces the temperature difference (Δt) across the vacuum insulated double wall  101 , thereby substantially reducing the heat energy loss to atmosphere and simultaneously preheats the input seawater. This arrangement also reduces the overall system size requirement and the surface area, which substantially reduces heat energy loss and increases system efficiency. 
         [0062]    Refer to  FIG. 4 ,  FIG. 5 ,  FIG. 8 , and  FIG. 8A . Seawater inters the condenser  300  through port  301  and flows through the outer first spiral channel  306  and connects with outlet port  302 . The condenser  300  provides an arc shaped vapor intake port  303  that connects with the second spiral channel  307  and is separated from channel  306  by a single spiral wall  308 . The wall  308  provides a thermally conductive path for the high temperature vapor in channel  307  to be transferred to the low temperature seawater in channel  306 . The lower temperature in channel  307  results in condensing the vapor into liquid. The liquid distilled water continues to flow through channel  307  to outlet port  304  of condenser  300  into port  204  of the feed through assembly  200  and exits the system through port  205  of the feed through assembly  200 . The preheated seawater flows out of the condenser  300  through outlet  302  and enters the evaporation chamber  500  through the nozzle assembly  801 . 
         [0063]    Refer to  FIG. 4 ,  FIG. 4A . The nozzle assembly  801  is designed to convert the preheated saltwater into a fine droplet-mist  503 . The preheated mist  503  is further heated by the hot upward airflow  502  and vaporizes, leaving the dry solid  908  that continue to fall. The vapor is forced upward by the airflow  502 . The vapor transfer assembly  400  mounted above the vaporization chamber  500  provides the airflow  502  and a square-toroid-shaped heater  600 , mounted near the lower midsection of the evaporation chamber  500  provides heat for the airflow  502 . 
         [0064]    As the droplet-mist  503  vaporizes into the density saturated vapor  501 , that is drawn upward by the air stream  504  and the dry solids  902  are extracted from the mist  503  and fall towards the bottom of the evaporation chamber  500 . Due to the toroid shape of the heater  600 , the air stream  800  directs the falling dry solids  902  toward the center of the evaporation chamber  500 . 
         [0065]    The dry solids  902  continue to fall through the center opening of the heater  600  and into a finned funnel assembly  700  where the dry solids  908  are cooled by the ambient temperature air flow  800  flowing through the feed-through assembly  200 . As the hot dry solids  908  fall towards the bottom of the evaporation chamber  500 , the hot dry solids  908  transfers heat to the cool air flow  907  being drawn into the system  100  through the central channel  206  of feed-through assembly  200 . The cool dry solids  908  continue to fall through the central channel  206  of the feedthrough assembly  200  where they are further cooled by the saltwater flowing through the intake port  202  of the feed-through assembly  200  before exiting the system  100 . 
         [0066]    In some embodiments, a transfer auger  903  may be provided to facilitate movement of the dry solids  908 . Whether a transfer auger  903  is required will depend upon the components of the dry solids  908 . In most environments the dry solids  908  will free flow without the need of the transfer auger  903 . 
         [0067]    The vapor  501  is drawn upward through a demister  904  by the vapor transfer assembly  400  and forced into the inner passageway  307  of the condenser  300  where the vapor is condensed into pure distilled liquid water  304  at near ambient temperature. The demister  904  prevents droplets that have not yet been vaporized from entering into the condenser  300 . The distilled water  304  flows from the condenser  300  and enters the feed-through assembly  200  through receiver port  204  where it is further cooled by the inflowing seawater, and exits through the exit port  205  of the feed-through assembly  200 . 
         [0068]    A structural insulation assembly  905  is positioned between the heater  600  and the funnel  700  that provides a low thermally conductive path from the heater  600  to the dry solids  908  that have fallen into the funnel  700 . 
         [0069]    When it is desirable to use solar energy instead of or in combination with electrical power, the square toroid shaped air heater  600  may be replaced with a similar shaped heater that uses hot water or steam as an energy source. 
         [0070]    Although particular embodiments of the present invention have been described in the foregoing description, it is to be understood that the present invention is not to be limited to just the embodiments disclosed, but that they are capable of numerous rearrangements, modifications and substitutions without departing from the description herein. 
         [0071]    All features disclosed in this specification, including any accompanying claims, abstract, and drawings, may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features. 
         [0072]    Although preferred embodiments of the present invention have been shown and described, various modifications and substitutions may be made thereto without departing from the spirit and scope of the invention. Accordingly, it is to be understood that the present invention has been described by way of illustration and not limitation.