WO2012047620A1

WO2012047620A1 - Systems and methods for solution concentration using electromagnetic energy

Info

Publication number: WO2012047620A1
Application number: PCT/US2011/053379
Authority: WO
Inventors: Shlomo Ben-Haim; Elliad Slicoff; Steven R. Rogers
Original assignee: Goji Ltd.
Priority date: 2010-09-28
Filing date: 2011-09-27
Publication date: 2012-04-12

Abstract

Methods, systems, and apparatuses for concentrating a solution are disclosed. The method may include forming a waterfall of the solution in a chamber, wherein substantially an entire flow of the waterfall is spaced apart from interior walls of the chamber, and applying electromagnetic energy to the waterfall for evaporating at least a portion of the solvent. The method may also include controlling application of the electromagnetic energy such that electromagnetic radiation applied to the waterfall at a first height location differs in at least one characteristic from electromagnetic radiation applied to the waterfall at a second height location along the waterfall.

Description

SYSTEMS AND METHODS FOR SOLUTION CONCENTRATION USING ELECTROMAGNETIC

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Application No. 61/387,362 filed September 28, 2010, and U.S. Provisional Application No. 61/418,695 filed December 1, 2010 the disclosures of which are incorporated herein in their entirety.

Technical Field

[0002] This Patent Application relates to systems and methods for applying electromagnetic energy, and more particularly but not exclusively to applying electromagnetic energy to purify or concentrate a solution.

Background

[0003] Water purification devices, such as Multi Stage Flash Distillation (MSF) and Multi Effect Distillation (MED) desalination systems, have been used to evaporate water, yielding a more concentrated solution. For example, in an MSF system, sea water vaporization takes place at moderate temperatures in vacuum, and the vapors condense to form fresh water. At vacuum pressures, the boiling point of water is lower, and evaporation requires less thermal energy. A brine heater typically heats the sea water to around 90 to 110°C. The hot brine then enters a flash chamber which is in a vacuum, where a portion of the water flash evaporates into steam. The steam rises to the upper part of the chamber and, on contact with condensing coils, condenses to form pure water. Salt and other impurities still remain within the balance of the brine at the bottom of the chamber.

[0004] Typically, MSF systems can achieve a freshwater yield of up to about 20%. Salts and other impurities will start building on the walls of the flash chambers, once the yield is increased to above 20%. Summary of a Few Exemplary Aspects of the Disclosure

[0005] An aspect of the disclosure is directed to a method for concentrating a solution. The method may be used, for example, for water desalination. The method may include forming a waterfall of the solution in a chamber, wherein substantially all of the flow of the waterfall is spaced apart from interior walls of the chamber. This may allow the solution to flow in the chamber without contacting the chamber walls and without fouling the wall, thus avoiding problems that may exist if the solution is in close contact with the walls.

[0006] The method may further include applying electromagnetic energy to the waterfall for evaporating at least a portion of the solvent. In some embodiments, the electromagnetic energy may be RF energy, deliverable at radio frequencies.

[0007] In some embodiments, the method may further include controlling the application of the electromagnetic energy according to a variation of the solution concentration along the waterfall. For example, the concentration of a solution may increase down the waterfall due to evaporation, and the energy application may be controlled to follow such variations in concentration. In one embodiment, the energy application may be controlled to optimize evaporation efficiency at the various different concentrations. For example, energy applied to the waterfall at a first height location may be controlled to differ from energy applied to the waterfall at a second height location. The difference may include one or more of various characteristics, for example, power, frequency, and/or phase.

[0008] In some embodiments, the method may include determining a value indicative of the ability of the waterfall to absorb energy at some conditions (also referred to herein as "a value indicative of absorbable energy"). Such a value may be determined at each of a plurality of height locations along the waterfall, and then used as a basis for determining different amounts of energy to be applied at these height locations.

[0009] More generally, differing energy delivery schemes may be determined for differing height locations, depending on parameters such as the values indicative of absorbable energy. An energy delivery scheme may include a sequence of parameter sets (each parameter set is also referred herein as a Modulation Space Element (MSE)), at which energy may be applied, as discussed in further detail below.

[0010] In some embodiments, determination of the energy delivery scheme may include applying electromagnetic energy to the waterfall using multiple MSEs; and determining evaporation efficiencies corresponding to the multiple MSEs. Evaporation efficiency at a given MSE may be determined, for instance, experimentally, by using the given MSE, and measuring the amount of solvent evaporated when certain amount of energy applied. Alternatively or additionally, indirect measures of the evaporation efficiency may be used. For example, values indicative of energy absorbable by the waterfall at the given MSE may serve as an indirect measure of evaporation efficiency. In some embodiments, an energy delivery scheme associated with high evaporation efficiency may be identified, and used for evaporating the solution.

[0011] In some embodiments, application of electromagnetic energy may include energy application via electromagnetic energy feeds placed at a plurality of height locations along the waterfall. Optionally, energy application may differ among feeds located at different height locations.

[0012] In some embodiments, the method may further include condensing at least some of the evaporated solvent to obtain liquid solvent. The obtained liquid solvent may be pure, and may be used or sold as pure solvent. In some embodiments, some of the obtained solvent may be used for washing the walls of the chamber. This may be particularly useful when contacting the solution may be detrimental to the inner walls of the chamber (for example, when the solution is corrosive to the interior wall of the chamber), but contacting the solvent may not.

[0013] In some embodiments, collecting the vapor may include providing gas to the chamber. The gas may be, for example, air. The gas may include some vapor of the solvent at a concentration much lower than saturation. Thus, the gas may absorb further vapor in the chamber. Evacuating the gas from the chamber may occur when the gas has a concentration of solvent vapor closer to saturation. In some embodiments, the vapor may be collected outside the chamber.

[0014] Evaporation efficiency may be increased by reducing the pressure in the chamber. Thus, in some embodiments, the method may further include controlling the pressure in the chamber such that it is below atmospheric pressure, for example, to a pressure of between 20mmHg and 200mmHg.

[0015] Another aspect of some of the disclosed embodiments may include an apparatus for concentrating a solution. The apparatus may include a chamber, configured to house a waterfall of the solution, wherein substantially all of the flow of the waterfall is spaced apart from interior walls of the chamber. The apparatus may further include an electromagnetic energy source, configured to apply electromagnetic energy to the waterfall for evaporating at least a portion of the solvent. The apparatus may be further configured for performing one or more of the methods discussed above. For example, it may include a controller for controlling energy application to different height locations in the waterfall, according to different energy delivery schemes.

[0016] In some embodiments, the apparatus may include one or more nozzles, configured to shape the waterfall. For example, in some embodiments, the nozzle may be configured to introduce the solution into the chamber as a plurality of droplets. The droplets may be separate, and the nozzle may be configured to control the size of the droplets, such that they are large enough to fall under gravity, but small enough to evaporate efficiently. Alternatively or additionally, the nozzle may dictate a general outline of the waterfall, for instance, it may delimit an angle at which the waterfall enters the chamber.

[0017] Another aspect of some of the disclosed embodiments may include a system for concentrating a solution. The system may include two apparatuses: one for concentrating a solution to a first concentration, and the second may be configured to receive a concentrated solution from the first, and further concentrate it. According to some embodiments of the present disclosure, the second apparatus may include a chamber configured to house a waterfall of the solution, wherein substantially all of the flow of the waterfall is spaced apart from interior walls of the chamber. The second apparatus may further include a source of electromagnetic energy configured to apply electromagnetic energy to the waterfall for evaporating at least a portion of the solvent.

[0018] Some exemplary aspects of this disclosure include a method for concentrating a solution, including a solvent and a solute. In some embodiments, the method may include forming a waterfall of the solution, and applying electromagnetic energy to the waterfall for evaporating at least a portion of the solvent. The method may further include controlling application of the electromagnetic energy such that electromagnetic radiation applied to the waterfall at a first height location differs in at least one characteristic from electromagnetic radiation applied to the waterfall at a second height location along the waterfall.

[0019] In some embodiments, the at least one differing characteristic may include a power level. For example, the power level associated with the electromagnetic radiation applied at the first height location is lower than a power level associated with the electromagnetic radiation applied at the second height location.

[0020] In some embodiments, the second height location is lower on the waterfall than the first height location. Alternatively, the second height location is higher on the waterfall than the first height location.

[0021] In some embodiments, the at least one differing characteristic may include a frequency and/or a phase.

[0022] In some embodiments, controlling application of the electromagnetic energy further include determining a value indicative of absorbable energy at each of a plurality of height locations along the waterfall to provide a set of values indicative of absorbable energy, and controlling amounts of electromagnetic energy applied at one or more height locations along the waterfall based on the set of values indicative of absorbable energy. [0023] In some embodiments, controlling application of the electromagnetic energy further includes determining an energy delivery scheme for applying the electromagnetic energy, such that an evaporation efficiency higher than a threshold value of 50% is achieved.

[0024] Optionally, the energy delivery scheme comprises a MSE, which includes at least one of a frequency, a phase, and an intensity or amplitude.

[0025] In some embodiments, determining the energy delivery scheme may include applying electromagnetic energy to the waterfall using multiple MSEs; determining evaporation efficiencies corresponding to the multiple MSEs; and identifying an energy delivery scheme comprising at least one of the multiple MSEs. The energy delivery scheme may correspond to an evaporation efficiency higher than a predetermined threshold value.

[0026] In some embodiments, the electromagnetic radiation applied to the waterfall at the first height location may be applied during a first time period that at least partially overlaps with a second time period during which the electromagnetic radiation is applied to the waterfall at the second height location.

[0027] In some embodiments, controlling application of the electromagnetic energy may include identifying multiple MSEs for applying the electromagnetic energy; and

determining and assigning weights to the multiple MSEs, such that application of electromagnetic energy in accordance with the multiple MSEs with the assigned weights would provide for an evaporation efficiency higher than a predetermined threshold value.

[0028] In some embodiments, controlling application of the electromagnetic energy may include identifying multiple MSEs for applying the electromagnetic energy; and applying the electromagnetic energy, in sequence, at each of the multiple MSEs. [0029] In some embodiments, controlling application of the electromagnetic energy may include controlling the application of electromagnetic energy according to different solute concentrations at different height locations along the waterfall.

[0030] In some embodiments, forming the waterfall may include forming a plurality of droplets of the solution. In some embodiments, applying electromagnetic energy may include applying electromagnetic energy via electromagnetic energy feeds placed at a plurality of height locations along the waterfall.

[0031] Some aspects of the disclosure relate to an apparatus for concentrating a solution including a solvent and a solute. The apparatus may include a chamber configured to house a waterfall of the solution; an electromagnetic source configured to apply electromagnetic energy to the waterfall for evaporating at least a portion of the solvent; and a controller configured to control the application of electromagnetic energy along the waterfall such that electromagnetic radiation applied to the waterfall at a first height location differs in at least one characteristic from electromagnetic radiation applied to the waterfall at a second height location along the waterfall.

[0032] In some embodiments, the controller may be configured to control the application of electromagnetic energy along the waterfall such that different amounts of electromagnetic energy are applied to different height locations along the waterfall.

[0033] In some embodiments, the apparatus may include a nozzle configured to introduce the solution into the chamber as a plurality of droplets.

[0034] In some embodiments, the electromagnetic energy source may include a plurality of electromagnetic energy feeds positioned at a plurality of height locations along the waterfall.

[0035] In some embodiments, the electromagnetic energy source may include one or more electromagnetic energy feeds positioned within the waterfall. [0036] In some embodiments, the apparatus may include a vapor collector. The vapor collector may be configured to provide dry air into the chamber for absorbing vapor of the solution, and

transfer air out of the chamber.

[0037] Some aspects of the disclosure may relate to a system for concentrating a solution. The system may include two coupled apparatuses. The first apparatus may be configured to concentrate the solution to a first solution having a first solute concentration. The first solution may include a solute and a solvent. The second apparatus may be configured to receive the first solution from the first apparatus and form a waterfall of the first solution. The second apparatus may be further configured to apply electromagnetic energy to the waterfall for evaporating at least a portion of the solvent; and control the application of electromagnetic energy such that electromagnetic radiation applied to the waterfall at a first height location differs in at least one characteristic from electromagnetic radiation applied to the waterfall at a second height location along the waterfall.

[0038] In some embodiments, the second apparatus may be configured to control the application of electromagnetic energy such that different amounts of electromagnetic energy are applied to different height locations along the waterfall.

[0039] Some aspects of the disclosure may include an apparatus for concentrating a solution, which includes a solvent and a solute. The apparatus may include a chamber, configured to house a waterfall of the solution, wherein substantially all of the flow of the waterfall is spaced apart from interior walls of the chamber; and an electromagnetic source configured to apply electromagnetic energy to the waterfall for evaporating at least a portion of the solvent.

[0040] An aspect of the disclosure may relate to an apparatus for concentrating a solution including a solvent and a solute, wherein substantially an entire flow of a waterfall of the solution remains spaced apart from any structural elements over at least a period of time during which the solvent is evaporated from the solution. [0041] An aspect of some of the disclosed embodiments may include a method for concentrating a solution including a solvent and a solute. This method may include forming a waterfall of the solution in a chamber, wherein substantially all of the flow of the waterfall is spaced apart from interior walls of the chamber; and applying electromagnetic energy to the waterfall for evaporating at least a portion of the solvent.

[0042] An aspect of some of the disclosed embodiments may include a method for concentrating a solution including a solvent and a solute. The method may include forming a waterfall of the solution; and applying electromagnetic energy to the waterfall for evaporating at least a portion of the solvent.

[0043] An aspect of some embodiments disclosed herein may include a controller for controlling electromagnetic energy applied to a waterfall of a solution. The controller may include a detector, to enable determination of one or more values indicative of absorbable energy of the solution along the waterfall; and a processor configured to control application of amounts of electromagnetic energy along the waterfall based on the one or more values indicative of absorbable energy of the solution.

[0044] In some embodiments, the one or more values include a value indicative of absorbable energy of the solution at each of a plurality of height locations along the waterfall, and the processor is configured to control application of amounts of electromagnetic energy at one or more height locations along the waterfall based on the values indicative of absorbable energy of the solution at the one or more height locations along the waterfall.

[0045] An aspect of the disclosure may include a method for controlling electromagnetic energy applied to a waterfall of a solution. The method may include determining a value indicative of absorbable energy of the solution at each of a plurality of height locations along the waterfall; and controlling application of electromagnetic energy at different MSEs at one or more height locations along the waterfall based on the value indicative of absorbable energy of the solution at the one or more height locations along the waterfall.

[0046] An aspect of some of the disclosed embodiments may include a controller for controlling electromagnetic energy applied to a waterfall of a solution. The controller may include a processor configured to receive information regarding a value indicative of absorbable energy of the solution at each of a plurality of height locations along the waterfall; and control application of amounts of electromagnetic energy at one or more height locations along the waterfall based on the values indicative of absorbable energy of the solution at the one or more height locations along the waterfall.

[0047] An aspect of some of the disclosed embodiments may include a method for purifying a solvent from a solution comprising the solvent and at least one solute. The method may include forming a waterfall of the solution in a chamber; applying electromagnetic energy to the waterfall for evaporating at least a portion of the solvent; controlling application of the electromagnetic energy such that electromagnetic radiation applied to the waterfall at a first height location differs in at least one characteristic from electromagnetic radiation applied to the waterfall at a second height location along the waterfall; and collecting vapor of the solvent to obtain the solvent, optionally, in a pure state.

[0048] In some embodiments, collecting the vapor may include providing gas to the chamber to absorb vapor, and transferring gas out of the chamber.

[0049] In any of the disclosed methods, apparatuses and systems, the solvent may be water and the solute may include one or more inorganic salt, ethylene glycol, and/or soaps or detergents.

[0050] An aspect of some embodiments may include a method for concentrating a solution including a solvent and a solute. The method may include forming a waterfall of the solution; determining differing characteristics of electromagnetic energy to be applied to the waterfall at differing height locations along the waterfall, such that an evaporation efficiency exceeds a predetermined threshold; and applying electromagnetic energy of the differing characteristics.

[0051] An aspect of some of the disclosed embodiments may include a method for purifying a solvent from a solution including the solvent and a solute. The method may include forming a waterfall of the solution; determining differing characteristics of electromagnetic energy to be applied to the waterfall at differing height locations along the waterfall, to evaporate solvent from the solution at an evaporation efficiency that exceeds a predetermined threshold; applying electromagnetic energy of the differing characteristics; and collecting vapor evaporated from the solution to obtain pure solvent.

[0052] An aspect of some embodiments of the disclosure may include a system for producing a pure solvent from a solution comprising the solvent and a solute. The system may include a first apparatus for concentrating the solution to a first solution having a first solute concentration, wherein the first solution includes a solute and a solvent; and a second apparatus coupled to the first apparatus. The second apparatus may be configured to receive the first solution from the first apparatus; form a waterfall of the first solution; apply electromagnetic energy to the waterfall for evaporating at least a portion of the solvent; control the application of electromagnetic energy such that electromagnetic radiation applied to the waterfall at a first height location differs in at least one characteristic from electromagnetic radiation applied to the waterfall at a second height location along the waterfall; and collect vapor evaporated from the solution to obtain pure solvent.

[0053] One or more of the disclosed apparatuses may include a heat exchanger. The heat exchanger may be configured to condense vapor obtained from the evaporation of the solution, and a collecting vessel to collect pure solvent condensed on the heat exchanger.

[0054] One or more of the disclosed apparatuses may include one or more sources of electromagnetic radiation configured to apply energy to the solution to evaporate solvent from the solution. [0055] In some embodiments, the one or more sources may be configured to apply electromagnetic energy of differing characteristics to the solvent at different height locations along the waterfall.

[0056] An aspect of some disclosed embodiments may include a method for purifying a solution including a solvent and a solute. The method may include forming a waterfall of the solution in a chamber, wherein substantially all of the flow of the waterfall is spaced apart from interior walls of the chamber; applying electromagnetic energy to the waterfall for evaporating at least a portion of the solvent; and collecting vapor evaporated from the solution to obtain pure solvent.

[0057] An aspect of some of the disclosed embodiments may include an apparatus for purifying a solvent from a solution. The apparatus may include a chamber with walls and a source of electromagnetic energy to apply energy to the interior of the chamber such that energy thus applied evaporates at least a portion of the solvent, wherein substantially an entire flow of a waterfall of the solution remains spaced apart from the walls and a portion of the evaporated solvent condenses on the walls to wash them of accumulated residue.

[0058] In some of the disclosed methods, forming a waterfall may include forming in a chamber, and the method may include controlling the pressure in the chamber to below atmospheric pressure, e.g., to a pressure between 20mmHg and 200mmHg.

[0059] In some embodiments, a method may include condensing at least some of the evaporated solvent to obtain liquid solvent; and washing the walls of the chamber with liquid solvent thus obtained.

[0060] In some embodiments, the solution may be corrosive to the walls of the chamber. Similarly, in some embodiments, the interior walls of the chamber may be susceptible to corrosion by the solution.

[0061] Some embodiments may include washing the walls of the chamber with the pure solvent. [0062] Some of the disclosed apparatuses may include a pipe going along the interior walls, the pipe having openings for dripping pure solvent on the interior walls of the chamber to wash the interior wall from solution of accumulated residue.

[0063] Unless otherwise defined, all technical and/or scientific terms are used consistently with their ordinary meaning as commonly understood by one of ordinary skill in the art to which the invention pertains. Although exemplary methods, apparatus, systems, and/or materials are described below, it is contemplated that those similar or equivalent to those described herein may also be used in the practice or testing of embodiments of the invention. In addition, the examples are illustrative only and are not intended to be necessarily limiting.

[0064] Implementation of the embodiments of the invention can involve performing or completing selected tasks manually, automatically, or a combination thereof. Moreover, some embodiments of the invention may be implemented by hardware, by software or by firmware or by a combination thereof using an operating system.

[0065] For example, hardware for performing selected tasks according to embodiments of the invention could be implemented as a chip or a circuit. Software for performing the selected tasks according to embodiments of the invention could be implemented as a plurality of software instructions being executed by a computer using any suitable operating system. In some embodiments of the invention, one or more tasks according to exemplary embodiments as described herein are performed by a processor, such as a computing platform for executing a plurality of instructions. Optionally, the embodiments may also include a volatile memory for storing instructions and/or data and/or a non-volatile storage, for example, a magnetic hard-disk and/or removable media, for storing instructions and/or data. Optionally, a network connection, a is provided as well. A display and/or a user input device such as a keyboard or mouse are optionally provided as well. Brief Description of the Drawings

[0066] Some embodiments of the invention are herein described, by way of example only, with reference to the accompanying drawings. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate disclosed embodiments described below:

In the drawings:

[0067] Fig. 1 is a schematic diagram of an apparatus for applying electromagnetic energy to an object, in accordance with some exemplary embodiments of the present invention;

[0068] Fig. 2 is a view of a cavity, in accordance with some exemplary embodiments of the present invention;

[0069] Fig. 3 is an illustration of an exemplary modulation space, in accordance with some exemplary embodiments of the present invention;

[0070] Fig. 4 is a schematic representation of an apparatus for applying electromagnetic energy to an object, in accordance with some exemplary embodiments of the present invention;

[0071] Fig. 5 is a flow chart of a method for applying electromagnetic energy to an energy application zone, in accordance with some embodiments of the present invention;

[0072] Fig. 6 is a diagrammatic representation of a solution concentration apparatus, in accordance with some embodiments of the present invention;

[0073] Fig. 7 is a diagrammatic representation of an apparatus 700 for concentrating a solution according to some embodiments of the invention;

[0074] Fig. 8 is a diagrammatic representation of a system for water desalination, in accordance with some embodiments of the present invention; and

[0075] Fig. 9 is a graphical representation of calculation results for the Mie scattering cross section Q as a function of the frequency. Detailed Description

[0076] Reference will now be made in detail to exemplary embodiments of the invention, examples of which are illustrated in the accompanying drawings. When appropriate, the same reference numbers are used throughout the drawings to refer to the same or like parts.

[0077] It is contemplated that the invention is not necessarily limited in its application to the details of construction and the arrangement of the components and/or methods set forth in the following description and/or illustrated in the drawings and/or the examples. The invention includes other embodiments and may be practiced or carried out in various ways.

[0078] Electromagnetic waves have been used in various applications to supply energy to objects. Consistent with embodiments of the present invention, electromagnetic waves may be applied to heat and concentrate a solution, for example brine. Alternatively or additionally, electromagnetic waves may be applied to cause evaporation of the solvent, thereby purifying it. For example, in some embodiments, the brine may be evaporated in a chamber such that contact between the brine and the chamber walls is minimized. Consistent with embodiments of the present invention, contactless heating may be performed, for example, through use of electromagnetic radiation.

[0079] A chamber may include an open, closed, or partially closed volume within which a liquid or a gas may flow. In some embodiments, the chamber may constitute part or all of an energy application zone, which will be introduced in more detail below. It is contemplated that the chamber may be of any suitable shape, such as cylindrical, cubical, etc.

[0080] The term brine is used herein to refer to a solution comprising water as a solvent and at least one salt as a solute. The salt may present in the form of ions, and the solution may include at least one cation and at least one anion. Examples of cations include Na⁺, K⁺, Mg⁺², and Ca⁺². Examples of anions include CI^", Br^", S0 ^~2 and C0₃ ^"2. The concentration of salts in the brine may be similar to that of sea water, for example, between about 3% to 4% w/v. In some embodiments, the concentration of the brine may be about twice that of sea water concentration, for example, 7%-8% w/v, which is the concentration at which brine typically leaves existing desalination plants and brought back to sea. It is contemplated that the present invention, however, is not limited to a solution of any particular solvent, solute, composition or concentration. Nor is the invention limited to dealing with solutions having single- phase, double-phase, or multiphase mixtures. For example, the invention may be used for separating fats from suspensions, among other applications.

[0081] In the context of the present application, the term solution refers to a liquid containing at least two chemical components, one in larger concentration than the other. The component of the larger concentration is referred to as a solvent, and the one or more components of lower concentration(s) are referred to collectively as solute. The solution may be clear, in which case the solute is dissolved in the solvent or forms a fine dispersion wherein the particles of the solute may be smaller than a wavelength of visible light, for example, smaller than about 400nm.

[0082] The concentration of the solution may be below saturation concentration, which is the concentration at which, at equilibrium, solid starts separating out of the solution. The solution may be supersaturated, in which case the concentration of the solute may be above saturation concentration, and the solution not in equilibrium. The solution may also be saturated or over saturated, in which case solute precipitates from the solution.

[0083] In one respect, the invention may include apparatus and methods for applying electromagnetic energy. The term electromagnetic energy, as used herein, includes energy deliverable at any or all portions of the electromagnetic spectrum, including but not limited to, radio frequency (RF), infrared (IR), near infrared, visible light, ultraviolet, etc. Applying energy in the RF portion of the electromagnetic spectrum is referred herein as applying RF energy. In one particular example, applied electromagnetic energy may include RF energy with a wavelength in free space of 100 km to 1 mm, which is a frequency of 3 KHz to 300 GHz, respectively. In some other examples, the frequency bands may be between 50 KHz to 3500 MHz or between 500 MHz to 1500 MHz or between 700 MHz to 1200 MHz or between 800 MHz - 1 GHz. Microwave and ultra high frequency (UHF) energy, for example, are both within the RF range. In some other examples, the applied electromagnetic energy may fall only within one or more Industrial-Scientific-Medical (ISM) frequency bands, for example, between 433.05 and 434.79 MHz, between 902 and 928 MHz, between 2400 and 2500 MHz, and/or between 5725 and 5875 MHz. Even though examples of the invention are described herein in connection with the application of RF energy, these descriptions are provided to illustrate a few exemplary principles of the invention, and are not intended to limit the invention to any particular portion of the electromagnetic spectrum. Further, the term RF radiation should be understood as an example of electromagnetic radiation, and RF energy should be understood as an example of electromagnetic energy.

[0084] In certain embodiments, the application of electromagnetic energy may occur in an "energy application zone", such as energy application zone 9, schematically depicted in Fig. 1. Such an energy application zone may include any void, location, region, or area where electromagnetic energy may be applied. It may include a hollow, or may be filled or partially filled with liquids, solids, gases, or combinations thereof. By way of example only, zone 9 may include an interior of an enclosure, interior of a partial enclosure, open space, solid, or partial solid, that allows existence, propagation, and/or resonance of electromagnetic waves. Zone 9 may include a conveyor belt or a rotating plate. For purposes of this disclosure, energy application zones may alternatively be referred to as cavities. It is to be understood that an object is considered "in" the energy application zone if at least a portion of the object is located in the zone or if some portion of the object receives delivered electromagnetic radiation.

[0085] Consistent with some embodiments, zone 9 may include a chamber enclosing a waterfall of solution. The chamber may include one or more energy application zones. In some embodiments, the chamber may be treated as a set of energy application zones, which may or may not overlap with each other. The energy application in each such zone may be determined independently of energy application in the other zones. In some embodiments, the chamber as a whole may be treated as one energy application zone, and the energy application to the zone may be determined collectively to create a desired field pattern in the zone.

[0086] In certain embodiments, electromagnetic energy may be applied to an "object". References to an "object" (also known as a "load" or "object to be heated") to which electromagnetic energy is applied is not limited to a particular form. An "object" or a "load" may include a liquid, semi-liquid, solid, semi-solid, or gas, depending upon the particular process with which the invention is utilized. For example, in some embodiments, the object may be or comprise a waterfall of a solution. The object may also include composites or mixtures of matter in differing phases, for example, a saturated solution, which comprises particulate solid solute.

[0087] In some embodiments, a waterfall of solution may be treated as a set of objects, each having similar or different characteristics. For example, in some embodiments, the waterfall may include portions that have different solute concentrations, and one or more of (or any combination of) these portions may be treated as an object. In some embodiments, energy application characteristics may be adjusted at one height location along the waterfall independently of energy application characteristics applied at other height locations. An energy application characteristic may be any characteristic that may directly or indirectly affect the manner, amount, location, and/or timing of the energy application. Adjusting the energy application characteristics may be feeds or by exciting different field patterns. Alternatively, the waterfall as a whole may be considered as a single object with differing characteristics associated with different height locations, and electromagnetic energy application may be controlled for efficiently evaporating solvent from this single object at different height locations. [0088] A waterfall may include any matter (e.g., a liquid, etc.) that flows. In some embodiments, the waterfall may include a solution that flows without substantially slowing down due to friction with structures around it. For example, the waterfall may include a flow of solution spaced apart from any structural elements. Spacing the waterfall apart from structural elements may reduce the risk of corrosion of the structural elements through, for example, contact with corrosive solutions. Such a flow configuration may enable processing of a wide range of solutions, for example, including brine comprising more than 20% salt, which absent a waterfall configuration could deposit corrosive substances within a pipe.

[0089] The flow of the waterfall may occur as a result of gravitational force, such that different points along the flow of the solution may have different heights. In some embodiments, the flow may be mainly due to pushing power or external pressure. The flow may be slowed by friction with the atmosphere around the solution. A waterfall may include a continuous body of flowing liquid. Alternatively or additionally, a waterfall may include many separated drops, each falling without touching the others along at least a portion of the path of descent. The waterfall may include droplets that are sufficiently large to fall under gravitational force, rather than to atomize into the atmosphere. In some embodiments, the waterfall may include a portion comprising a continuous body of flowing solution along with another portion including a plurality of droplets.

[0090] In some embodiments, the solution may include toxic or hazardous materials. For example, the solution may include heavy metal salts (e.g., from batteries, electro voltaic cells, and/or electronics). A toxic or hazardous solution may include, for example, salts of lead, mercury, cadmium, and/or chromium. Applying the disclosed methods may result in a decrease in the solution volume (e.g., due to solvent evaporation), and thus a decrease in the cost of waste treatment. In some embodiments, the evaporated solvent may be recycled for further use. In some embodiments, the disclosed waterfall evaporation may be combined with other separation techniques, for example, with multi-effect distillation, for the treatment of toxic or hazardous materials.

[0091] In some embodiments, the solution is corrosive. A material is considered corrosive if it damages the surface of the chamber by contact. The damage may be irreversible.

[0092] A corrosive solution may comprise a non-corrosive solvent (for example, water) and a corrosive solute (for example, sea salt). In such cases, some of the pure solvent obtained by evaporation, may be used for washing the walls of the chamber from corrosive solute. Additionally or alternatively, liquids of other origin may be used to wash the walls during operation of the waterfall. Because the solution falls in the waterfall without contacting the walls, it is possible to wash the walls without interrupting with the operation of the evaporation process.

[0093] Fig. 1 is a diagrammatic representation of an apparatus 100 for applying electromagnetic energy to an object. Apparatus 100 may include a controller 101, an array 102 of antennas 102 including one or more antennas, and an energy application zone 9. Controller 101 may be electrically coupled to one or more antennas 102. As used herein, the term "electrically coupled" refers to one or more either direct or indirect electrical connections. Controller 101 may include a computing subsystem 92, an interface 130, and an electromagnetic energy application subsystem 96. Based on an output of computing subsystem 92, energy application subsystem 96 may respond by generating one or more radio frequency signals to be supplied to antennas 102. In turn, the one or more antennas 102 may radiate electromagnetic energy into energy application zone 9. In certain embodiments, this energy can interact with an object 11 positioned within energy application zone 9, for example, with waterfall 613 running within chamber 606 (see Fig. 6).

[0094] Consistent with some presently disclosed embodiments, computing subsystem 92 may include a general purpose or special purpose computer. Computing subsystem 92 may be configured to generate control signals for controlling electromagnetic energy application subsystem 96 via interface 130. Computing subsystem 92 may further receive measured signals from electromagnetic energy application subsystem 96 via interface 130. While controller 101 is illustrated for exemplary purposes as having three subcomponents, control functions may be consolidated in fewer components, or additional components may be included consistent with the desired function and/or design of a particular embodiment.

[0095] Exemplary energy application zone 9 may include locations where energy is applied in an oven, chamber, tank, dryer, thawer, dehydrator, reactor, engine, chemical or biological processing apparatus, incinerator, material shaping or forming apparatus, conveyor, combustion zone, cooler, freezer, etc. Thus, consistent with the presently disclosed embodiments, energy application zone 9 may include a cavity 10 (e.g., an electromagnetic resonator also known as cavity resonator) illustrated, for example, in Fig. 2 or 4). At times, energy application zone 9 may be coincident with the waterfall (or other object) or a portion of the waterfall (i.e., the waterfall, or a portion thereof, is or defines the energy application zone).

[0096] Fig. 2 shows a top sectional view of a cavity 200, which is an exemplary embodiment of energy application zone 9. Fig. 2 shows antennas 210 and 220 as examples of antennas 102 shown in Fig. 1. Cavity 200 may be cylindrical in shape and may be made of a conductor, such as aluminum, stainless steel or any suitable metal or other conductive material. Cavity 200 may be resonant in a predetermined range of frequencies (e.g., the UHF or microwave range of frequencies, such as between 300 MHz and 3 GHz, or between 400 MHz and 1 GHZ). It is contemplated that cavity 200 may be of any other suitable shapes including, for example, cylindrical, semi-cylindrical, rectangular, elliptical, cuboid, right prism, etc. In the presently disclosed embodiments, cavity 200 may even be of an irregular or asymmetrical shape. It is also contemplated that cavity 200 may be closed, i.e., completely enclosed (e.g., by conductor materials), bounded at least partially, or open, i.e., having non-bounded openings. The general methodology of the invention is not limited to any particular cavity shape or configuration, as discussed earlier. Cavity 200 comprises a space 230 for receiving object 11 (shown in Fig. 1 and 4). Space 230, as shown between the dotted lines in Fig. 2, has an essentially rectangular cross section. In some embodiments, spaces with substantially circularly cross-section are used. In some embodiments, the dashed lines 240 may be imaginary borders defining space 230. In some embodiments, RF transparent walls 240 may define space 230. RF transparent walls 240 may allow RF energy emitted by radiating elements 210 or 220 to participate in heating object 11, for example, participate in evaporation of solvent from a waterfall. Thus, RF transparent walls 240 may be opaque to RF at some frequency ranges (e.g. ranges not emitted by radiating elements 210 and 220), or partly transparent in one or more frequency ranges. In some embodiments, field adjusting element(s) (not illustrated) may be provided in energy application zone 9, for example, in cavity 10 and/or cavity 200. Field adjusting element(s) may be adjusted to change the electromagnetic wave pattern in the cavity in a way that selectively directs the electromagnetic energy from one or more of antennas 210 and 220 102, or 2018) into object 11. Optionally, the field adjusting elements are used to selectively direct the electromagnetic energy to an outer surface of the waterfall, from which solvent may evaporate more easily. Additionally or alternatively, field adjusting element(s) may be further adjusted to simultaneously match at least one of the antennas that act as transmitters, and thus reduce coupling to the other antennas that act as receivers.

[0097] Additionally, one or more sensor(s) 20 may be used to sense information (e.g., signals) relating to object 11 and/or the energy application process and/or the energy application zone. At times, one or more antennas, e.g., antenna 210 or 220, may be used as sensors. The sensors may be used to sense any information as known in the art, including electromagnetic power, temperature, weight, humidity, motion, etc. The sensed information may be used for any purpose as known in the art, including process verification, automation, safety, etc. [0098] In the presently disclosed embodiments, one or more feeds and/or a plurality of radiating elements (e.g., antennas) may be provided. The radiating elements may be located on one or more surfaces of the energy application zone. Alternatively, radiating elements may be located inside or outside the energy application zone. One or more of the radiating elements may be near to, in contact with, in the vicinity of or even embedded in the object (e.g., when the object is a liquid). The orientation and/or configuration of each radiating element may be distinct or the same, based on the specific energy application, e.g., based on a desired target effect. For example, each radiating element may be positioned, adjusted, and/or oriented to transmit electromagnetic waves along a same direction, or various different directions. Furthermore, the location, orientation, and configuration of each radiating element may be predetermined before applying energy to the object, or dynamically adjusted using a processor while applying energy. Moreover, the location, orientation, and configuration of each radiating element may be dynamically adjusted, for example, using a processor during operation of the apparatus, between rounds of energy application. The invention is not limited to radiating elements having particular structures or which are necessarily located in particular areas or locations within the apparatus.

[0099] As schematically depicted in the block diagram of Fig. 1, apparatus 100 may include at least one radiating element in the form of at least one antenna 102 for delivery of electromagnetic energy to the energy application zone 9. One or more of the antenna(s) may also be configured to receive electromagnetic energy via zone 9. In other words, an antenna, as used herein may function as a transmitter, a receiver, or both, depending on a particular application and configuration. When an antenna acts as a receiver for electromagnetic energy from an energy application zone (e.g., reflected electromagnetic waves), the antenna is said to receive electromagnetic energy via the zone.

[00100] As used herein, the terms "radiating element" and "antenna" (including RF antenna) may broadly refer to any structure from which electromagnetic energy may radiate and/or be received, regardless of whether the structure was originally designed for the purposes of radiating or receiving energy, and regardless of whether the structure serves any additional function. For example, a radiating element or an antenna may include an aperture/slot antenna, or an antenna which includes a plurality of terminals transmitting in unison, either at the same time or at a controlled dynamic phase difference (e.g., a phased array antenna). Consistent with some exemplary embodiments, antennas 102 may include an electromagnetic energy transmitter (referred to herein as "a transmitting antenna") that feeds energy into electromagnetic energy application zone 9, an electromagnetic energy receiver (referred herein as "a receiving antenna") that receives energy from zone 9, or a combination of both a transmitter and a receiver. For example, a first antenna may be configured to supply electromagnetic energy to zone 9, and a second antenna may be configured to receive energy from the first antenna. In some embodiments, one or more antennas may each serve as both receivers and transmitters. In some embodiments, one or more antennas may serve a dual function while one or more other antennas may serve a single function. So, for example, a single antenna may be configured to both deliver electromagnetic energy to the zone 9 and to receive electromagnetic energy via the zone 9; a first antenna may be configured to deliver electromagnetic energy to the zone 9, and a second antenna may be configured to receive electromagnetic energy via the zone 9; or a plurality of antennas could be used, where at least one of the plurality of antennas is configured to both deliver electromagnetic energy to zone 9 and to receive electromagnetic energy via zone 9. At times, in addition to or as an alternative to delivering and/or receiving energy, an antenna may also be adjusted to affect the field pattern. For example, various properties of the antenna, such as position, location, orientation, temperature, etc., may be adjusted. Different antenna property settings may result in differing electromagnetic field patterns within the energy application zone thereby affecting energy absorption in the object. Therefore, antenna adjustments may constitute one or more variables that can be varied in an energy delivery scheme.

[00101] Consistent with the presently disclosed embodiments, energy may be supplied and/or provided to one or more transmitting antennas. Energy supplied to a transmitting antenna may result in energy emitted by the transmitting antenna (referred to herein as "incident energy"). The incident energy may be delivered to zone 9, and may be in an amount equal to the one that is supplied to the transmitting antenna(s) by a source (also referred herein as "a source of electromagnetic energy/' "a source of electromagnetic radiation," "an electromagnetic energy source," or "an electromagnetic source"). The source of electromagnetic energy may include, for example, an RF power supply and an amplifier. In some embodiments, the source may also include a modulator. An exemplary source is shown in Fig. 4 as part 2011. A portion of the incident energy may be dissipated by the object (referred to herein as "dissipated energy"). Another portion may be reflected at the transmitting antenna (referred to herein as "reflected energy"). Reflected energy may include, for example, energy reflected back to the transmitting antenna due to mismatch caused by the object and/or the energy application zone, e.g., impedance mismatch. Reflected energy may also include energy retained by the port of the transmitting antenna (i.e., energy that is emitted by the antenna but does not flow into the zone). The rest of the incident energy, other than the reflected energy and dissipated energy, may be transmitted to one or more receiving antennas other than the transmitting antenna (referred to herein as "transmitted energy."). Therefore, the incident energy ("I") supplied to the transmitting antenna may include all of the dissipated energy ("D"), reflected energy ("R"), and transmitted energy ("T"), the relationship of which may be represented mathematically as / = D + R + .

[00102] In accordance with certain aspects of the invention, the one or more transmitting antennas may deliver electromagnetic energy into zone 9. Energy delivered by a transmitting antenna into the zone (referred to herein as "delivered energy" or (d)) may be the incident energy emitted by the antenna minus the reflected energy at the same antenna). That is, the delivered energy may be the net energy that flows from the transmitting antenna to the zone, i.e., d=l-R. Alternatively, the delivered energy may also be represented as the sum of dissipated energy and transmitted energy, i.e., d=D+T (where T=∑Ti).

[00103] In certain embodiments, the application of electromagnetic energy may occur via one or more power feeds. A feed may include one or more waveguides and/or one or more radiating elements (e.g., antennas 102) for applying electromagnetic energy to the zone. Such antennas may include, for example, patch antennas, fractal antennas, helix antennas, log-periodic antennas, spiral antennas, slot antennas, dipole antennas, loop antennas, slow wave antenna, leaky wave antenna or any other structure capable of transmitting and/or receiving electromagnetic energy.

[00104] The invention is not limited to antennas having particular structures or which are necessarily located in particular areas or regions. Antennas, e.g., antenna 102, may be polarized in differing directions in order to, for example, reduce coupling, enhance specific field pattern(s), increase the energy delivery efficiency and support and/or enable a specific algorithm(s). The foregoing are examples only, and polarization may be used for other purposes as well. In one example, three antennas may be placed parallel to orthogonal coordinates, however, it is contemplated that any suitable number of antennas (such as one, two, three, four, five, six, seven, eight, etc.) may be used. For example, a higher number of antennas may add flexibility in system design and improve control of energy distribution, e.g., greater uniformity and/or resolution of energy application in zone 9.

[00105] Alternatively or additionally to radiating element(s), e.g., antenna(s) 102, one or more slow wave antenna(s) may be provided in the energy application zone in some embodiments. A slow-wave antenna may refer to a wave-guiding structure that possesses a mechanism that permits it to emit power along all or part of its length. The slow wave antenna may comprise a plurality of slots to enable electromagnetic (EM) energy to be emitted. In some embodiments, the waterfall may be formed in the energy application zone so that a coupling may be formed between an evanescent EM wave (e.g., emitted from a slow wave antenna) and solvent in the waterfall. An evanescent EM wave in free space (e.g., in the vicinity of the slow wave antenna) may be non-evanescent in the object.

[00106] Antennas, e.g., antenna 102, may be configured to feed energy at specifically chosen modulation space elements, referred herein as MSEs, which are optionally chosen by controller 101. The term "modulation space" or "MS" is used to collectively refer to all the parameters that may affect a field pattern in the energy application zone and all combinations thereof. In some embodiments, the "MS" may include all possible components that may be used and their potential settings (absolute and/or relative to others) and adjustable parameters associated with the components. For example, the "MS" may include a plurality of variable parameters, the number of antennas, their positioning and/or orientation (if modifiable), the useable bandwidth, a set of all useable frequencies and any combinations thereof, power settings, phases, etc. The MS may have any number of possible variable parameters, ranging between one parameter only (e.g., a one dimensional MS limited to frequency only or phase only-or other single parameter), two or more dimensions (e.g., varying frequency and amplitude or varying frequency and phase together within the same MS), or many more.

[00107] Each variable parameter associated with the MS is referred to as an MS dimension. By way of example, Fig. 3 illustrates a three dimensional modulation space 300, with three dimensions designated as frequency (F), phase (P), and amplitude (A). That is, in MS 300, frequency, phase, and amplitude (e.g., an amplitude difference between two or more waves being transmitted at the same time) of the electromagnetic waves may be modulated during energy delivery, while all the other parameters may be predetermined and fixed during energy delivery. In Fig. 3, the modulation space is depicted in three dimensions for ease of discussion only. The MS may have any other number of dimensions, e.g., one dimension, two dimensions, four dimensions etc. In one example a one dimension oven may provide MSEs that differ one from the other only by frequency.

[00108] The term "modulation space element" or "MSE," may refer to a specific set of values of the variable parameters in MS. Therefore, the MS may also be considered to be a collection of all possible MSEs. For example, two MSEs may differ one from another in the relative amplitudes of the energy being supplied to a plurality of radiating elements. For example, Fig. 3 shows an MSE 301 in the three- dimensional MS 300. MSE 301 has a specific frequency F(i), a specific phase P(i), and a specific amplitude A(i). If even one of these MSE variables change, then the new set defines another MSE. For example, (3 GHz, 30^, 12 V) and (3 GHz, 602, 12 v) are two different MSEs, although only the phase component changes.

[00109] Differing combinations of these MS parameters will lead to differing field patterns across the energy application zone and differing energy distribution patterns in the object. A plurality of MSEs that can be executed sequentially or simultaneously to excite a particular field pattern in the energy application zone, may be collectively referred to as an "energy delivery scheme." For example, an energy delivery scheme may consist of three MSEs: (F(l), P(l), A(l)); (F(2), P(2), A(2)); and (F(3), P(3), A(3)). Such energy application scheme may result in applying the first, second, and third MSE to the energy application zone. Optionally, the energy application scheme also includes weights for the different MSEs. The weights may dictate the relative energy to be transferred by each of the MSEs included in the scheme. The weights may determine relative energy by determining relative time application of each of the MSEs, determining relative powers for each of the MSEs, or a combination of both.

[00110] Any suitable or desired number of MSEs or combinations of MSEs may be used in accordance with the invention. Differing MSE combinations may be used depending on the requirements of a particular application and/or on a desired energy transfer profile, and/or given equipment, e.g., cavity dimensions. The num ber of options that may be employed could be as few as two or as many as the designer desires, depending on factors such as intended use, level of desired control, hardware or software resolution and cost.

[00111] Different energy delivery schemes may excite different field patterns in the energy application zone. In some embodiments, a target field pattern may be first determined or selected from available patterns (e.g. based on observable properties of the waterfall), and then availa ble MSEs are weighted such that their weighted sum excites the target field pattern. The weighted MSEs may be collectively referred to as an energy delivery scheme. Once the energy delivery scheme is determined, the processor may control the source to execute the energy delivery scheme by seq uentially supplying energy at the MSEs according to their respective weights. This may result in exciting the selected field pattern in the energy application zone.

[00112] In certain embodiments, there may be provided at least one processor. As used herein, the term "processor" may include an electric circuit that performs a logic operation on input or inputs. For example, such a processor may include one or more integrated circuits, microchips, microcontrollers, microprocessors, all or part of a central processing unit (CPU), graphics processing unit (GPU), digital signal processors (DSP), field-programmable gate array (FPGA) or other circuit suita ble for executing instructions or performing logic operations.

[00113] The instructions executed by the processor may, for example, be preloaded into the processor or may be stored in a separate memory unit such as a RAM, a ROM, a hard disk, an optical disk, a magnetic medium, a flash memory, other permanent, fixed, or volatile memory, or any other mechanism capable of storing instructions for the processor. The processor(s) may be customized for a particular use, or can be configured for general-purpose use and can perform different functions by executing different software. [00114] If more than one processor is employed, all may be of similar construction, or they may be of differing constructions electrically connected or disconnected from each other. They may be separate circuits or integrated in a single circuit. When more than one processor is used, they may be configured to operate independently or collaboratively. They may be coupled electrically, magnetically, optically, acoustically, mechanically or by other means permitting them to interact.

[00115] The at least one processor may be configured to cause electromagnetic energy to be applied to zone 9 via one or more antennas configured to apply electromagnetic energy to object 11, for example, at each of a series of MSEs. In some embodiments, the at least one processor may be configured to regulate one or more other components of controller 101 in order to cause the energy to be applied.

[00116] The at least one processor may be coincident with or may be part of controller 101. In certain embodiments, the at least one processor may be configured to determine a value indicative of energy absorbable by the waterfall at a given height location at each of a plurality of MSEs (e.g., at a plurality of frequencies). This may occur, for example, using one or more lookup tables, by preprogramming the processor or memory associated with the processor, and/or by testing a solution in an energy application zone to determine its absorbable energy characteristics. One exemplary way to conduct such a test is through a sweep.

[00117] As used herein, a sweep may include, for example, energy delivery over time at more than one MSE. For example, a sweep may include the sequential delivery at multiple MSEs in one or more contiguous MSE band; the sequential delivery at multiple MSEs in more than one non-contiguous MSE band; the sequential delivery of energy at individual non-contiguous MSEs; and/or the delivery of synthesized pulses having a desired MSE/power spectral content (i.e., a synthesized pulse in time). The MSE bands may be contiguous or non-contiguous. Thus, during an MSE sweeping process, the at least one processor may regulate the energy supplied to the at least one antenna to sequentially deliver electromagnetic energy at various MSEs to zone 9, and to receive feedback which serves as an indicator of the energy absorbable by object 11, for example, by a waterfall at a given height location thereof. While the invention is not limited to any particular measure of feedback indicative of energy absorption in the object, various exemplary indicative values are discussed below.

[00118] During the sweeping process, electromagnetic energy application subsystem 96 may be regulated to receive electromagnetic energy reflected and/or coupled (also referred herein as "transmitted energy") at antenna(s) 102, and to communicate the measured energy information (e.g., information pertaining and/or related and/or associated with the measured energy) back to computing subsystem 92 via interface 130, as illustrated in Fig. 1. Computing subsystem 92 may then be regulated to determine a value indicative of energy absorbable by object 11 at each of a plurality of MSEs based on the received information. Consistent with some of the presently disclosed embodiments, a value indicative of the absorbable energy may be a dissipation ratio (referred to herein as "DR") associated with each of a plurality of MSEs. As referred to herein, a "dissipation ratio" (or "absorption efficiency" or "power efficiency"), may be defined as a ratio between electromagnetic energy absorbed by object 11 and electromagnetic energy supplied into electromagnetic energy application zone 9. In some other embodiments, a "dissipation ratio" may be defined as a ratio between electromagnetic energy absorbed by object 11 and electromagnetic energy delivered into electromagnetic energy application zone 9.

[00119] Energy that may be dissipated or absorbed by an object may be referred to herein as "absorbable energy" or "absorbed energy". Absorbable energy may be an indicator of the object's capacity to absorb energy or the ability of the apparatus to cause energy to dissipate in a given object (for example - an indication of the upper limit thereof). In some of the presently disclosed embodiments, absorbable energy may be calculated as a product (multiplicative product) of the incident energy (e.g., maximum incident energy) supplied to the at least one antenna and the dissipation ratio. Similarly, energy absorption rate may be calculated as a product of the incident power supplied to the at least one antenna and the dissipation ratio. Reflected energy (i.e., the energy not absorbed or transmitted) may, for example, be a value indicative of energy absorbed by the object. By way of another example, a processor might calculate or estimate absorbable energy based on the portion of the incident energy that is reflected and the portion that is transmitted. That estimate or calculation may serve as a value indicative of absorbed and/or absorbable energy.

[00120] During an MSE sweep, for example, the at least one processor may be configured to control a source of electromagnetic energy such that energy is sequentially supplied to an object at a series of MSEs. The at least one processor may then receive a signal indicative of energy reflected at each MSE and optionally also a signal indicative of the energy supplied to other antennas at each MSE. Using a known amount of incident energy supplied to the antenna and a known amount of energy reflected and/or transmitted (i.e., thereby indicating an amount absorbed at each MSE), an absorbable energy indicator may be calculated or estimated. Alternatively, the processor may rely on an indicator of reflection and/or transmission as a value indicative of absorbable energy.

[00121] Absorbable energy may also include energy that may be dissipated by the structures of the energy application zone in which the object is located, e.g., cavity walls or leakage of energy at an interface between an oven cavity and an oven door. Because absorption in metallic or conducting material (e.g., the cavity walls or elements within the cavity in some embodiments) may be characterized by a large quality factor (also known as a "Q factor"), MSEs having a large Q factor may be identified as being coupled to conducting material, and at times, a choice may be made not to transmit energy in such MSEs. In that case, the amount of electromagnetic energy absorbed in the cavity walls may be substantially small, and thus, the amount of electromagnetic energy absorbed in the object may be substantially equal to the amount of absorbable energy.

[00122] In some of the presently disclosed embodiments, a dissipation ratio may be calculated using formula (1):

where P_in represents the electromagnetic energy supplied into zone 9 by antennas 102, Pr_f represents the electromagnetic energy reflected/returned at those antennas that function as transmitters, and P_cp represents the electromagnetic energy coupled at those antennas that function as receivers. DR may be a value between 0 and 1, and thus may be represented by a percentage number.

[00123] For example, consistent with an embodiment which is designed for three antennas 1, 2, and 3, computing subsystem 92 may be configured to determine input reflection coefficients S , S₂2, and S₃₃ and the transfer coefficients may be

based on a measured power and/or energy information during the sweep. Accordingly, the dissipation ratio DR corresponding to antenna 1 may be determined based on the above mentioned reflection and transmission coefficients, according to formula (2):

DR = l-(ISiil²+ISi₂l²+ISi₃l²). (2)

[00124] The value indicative of the absorbable energy may further involve the maximum incident energy associated with a power amplifier (not illustrated) of subsystem 96 at the given MSE. As referred herein, a "maximum incident energy" may be defined as the maximal power that may be provided to the antenna at a given MSE throughout a given period of time. Thus, one alternative value indicative of absorbable energy may be the product of the maximum incident energy and the dissipation ratio. These are just two examples of values that may be indicative of absorbable energy which could be used alone or together as part of control schemes implemented in controller 101. Alternative indicia of absorbable energy may be used, depending for example on the structure employed and the application. [00125] In certain embodiments, the at least one processor may also be configured to cause energy to be supplied to the at least one radiating element over a subset of a plurality of MSEs. In such embodiments, energy transmitted to the zone at each of the subset of MSEs may be a function of the absorbable energy value at the corresponding MSE. For example, energy transmitted to the zone at MSE(i) may be a function of the absorbable energy value at MSE(i). The energy supplied to at least one antenna 102 at each of the subset of MSEs may be determined as a function of the absorbable energy value at each MSE (e.g., as a function of a dissipation ratio, maximum incident energy, a combination of the dissipation ratio and the maximum incident energy, or some other indicator). In some embodiments, the subset of the plurality of MSEs and/or the energy transmitted to the zone at each of the subset of MSEs may be determined based on or in accordance with a result of absorbable energy information (e.g., absorbable energy feedback) obtained during a MSE sweep (e.g., at the plurality of MSEs). That is, using the absorbable energy information, the at least one processor may adjust energy supplied at each MSE such that the energy at a particular MSE may in some way be a function of an indicator of absorbable energy at that MSE. The functional correlation may vary depending upon application and/or a desired target effect, e.g., an energy distribution profile corresponding to composition (e.g. salt concentration in brine) and/or temperature variation may be desired across object 11, for example, along the waterfall. The invention is not limited to any particular scheme, but rather may encompass any technique for controlling the energy supplied by taking into account an indication of absorbable energy.

[00126] In certain embodiments, the at least one processor may be configured to cause energy to be supplied to the at least one radiating element in at least a subset of the plurality of MSEs, wherein energy supplied to the zone at each of the subset of MSEs is inversely related to the absorbable energy value at the corresponding MSE. Such an inverse relationship may involve a general trend- when an indicator of absorbable energy in a particular MSE subset (i.e., one or more MSEs) tends to be relatively high, the actual incident energy at that MSE subset may be relatively low. And when an indicator of absorbable energy in a particular MSE subset tends to be relatively low, the incident energy may be relatively high. The inverse relationship may be even more closely correlated. For example, the transmitted energy may be set such that its product (multiplicative product) with the absorbable energy value (i.e., the absorbable energy by object 11) is substantially constant across the MSEs applied.

[00127] Some exemplary energy delivery schemes may lead to more spatially uniform energy absorption in the object. As used herein, "spatial uniformity" may refer to a condition where the absorbed energy across the object or a portion (e.g., a selected portion) of the object that is targeted for energy application is substantially constant (for example per volume unit or per mass unit). In some embodiments, the energy absorption may be considered substantially constant if the variation of the dissipated energy at different locations of the object is lower than a threshold value. For instance, a deviation may be calculated based on the distribution of the dissipated energy in the object, and the absorbable energy may be considered substantially constant if the deviation between the dissipation values of different parts of the object is less than 50%. Because in many cases spatially uniform energy absorption may result in a spatially uniform temperature increase, consistent with the presently disclosed embodiments, spatial uniformity may also refer to a condition where the temperature increase across the object or a portion of the object that is targeted for energy application is substantially constant. The temperature increase may be measured by a sensing device, for example a temperature sensor provided in zone 9. In some embodiments, spatial uniformity may be defined as a condition, where a given property of the object is uniform or substantially uniform after processing, e.g., after a heating process. Examples of properties may include temperature, mean particle size, etc.

[00128] In order to achieve control over the spatial pattern of energy absorption in an object or a portion of an object, controller 101 may be configured to hold substantially constant the amount of time at which energy is supplied to antennas 102 at each MSE, while varying the amount of power supplied at each MSE as a function of the absorbable energy value. In some embodiments, controller 101 may be configured to cause the energy to be supplied to the antenna at a particular MSE or MSEs at a power level substantially equal to a maximum power level of the device and/or the amplifier at the respective MSE(s).

[00129] Alternatively or additionally, controller 101 may be configured to vary the period of time during which energy is applied to each MSE as a function of the absorbable energy value. At times, both the duration and power at which each MSE is applied are varied as a function of the absorbable energy value. Varying the power and/or duration of energy supplied at each MSE may be used to cause substantially uniform energy absorption in the object or to have a controlled spatial pattern of energy absorption, for example, based on feedback from the dissipation properties of the load at each transmitted MSE.

[00130] Consistent with some other embodiments, controller 101 may be configured to cause the amplifier to supply no energy at all at particular MSE(s). Similarly, if the absorbable energy value exceeds a predetermined threshold, controller 101 may be configured to cause the antenna to supply energy at a power level less than a maximum power level of the antenna.

[00131] Because absorbable energy can change based on a host of factors including object temperature, depending on application, in some embodiments, it may be beneficial to regularly update absorbable energy values and adjust energy application based on the updated absorption values. These updates can occur multiple times a second, or can occur every few seconds or longer, depending on the requirements of a particular application.

[00132] In accordance with an aspect of some embodiments of the invention, the at least one processor may be configured to determine a desired and/or target energy absorption level at each of a plurality of MSEs and adjust energy supplied from the antenna at each MSE in order to obtain the target energy absorption level at each MSE. For example, controller 101 may be configured to target a desired energy absorption level at each MSE in attempt to achieve or approximate substantially uniform energy absorption across a range of MSEs.

[00133] Alternatively, controller 101 may be configured to target energy absorption level at each of a plurality of object portions, which collectively may be referred to as an energy absorption profile across the object. An absorption profile may target uniform energy absorption in the object, non-uniform energy absorption in the object, differing energy absorption values in differing portions of the object, substantially uniform absorption in one or more portions of the object etc.

[00134] In some embodiments, the at least one processor may be configured to adjust energy supplied from the antenna at each MSE in order to obtain a desired target energy effect and/or energy effect in the object, for example: a different amount of energy may be provided to different parts and/or regions of the object.

[00135] In some embodiments, a resolution of the different regions (for example, to which different amounts of energy are applied) and/or a resolution of a discretization of the zone (e.g., the zone may be divided into a plurality of regions) may be a fraction of the wavelength of the delivered EM energy, e.g., on the order of λ/10, λ/5, λ/2. For example, for a frequency of 900MHz, the corresponding wavelength (λ) in air (ε=1) is 33.3 cm and the resolution may be on the order of 3 cm, e.g., (3cm)³ resolution. In water, for example, the wavelength is approximately 9 times shorter at the same frequency (900MHz), thus the resolution may be in the order of 0.33 cm, e.g., (0.33cm)³. Adding salt to a water-based solution can increase the wavelength, and the wavelength may continue to increase with increasing salt concentration.

[00136] Reference in now made to Fig. 4, which illustrates an exemplary apparatus 100 for applying electromagnetic energy to an object. In accordance with some embodiments, apparatus 100 may include a processor 2030 that may control a source 2011, which may include an RF power supply 2012, a modulator 2014, and an amplifier 2016. Controlling the source may include, for example, regulating modulations performed by modulator 2014. In some embodiments, modulator 2014 may include at least one of a phase modulator, a frequency modulator, and an amplitude modulator configured to modify the phase, frequency, and amplitude of an AC waveform generated by power supply 2012. Processor 2030 may alternatively or additionally regulate at least one of location, orientation, and configuration of each radiating element 2018, for example, using an electro-mechanical device. Such an electromechanical device may include a motor or other movable structure for rotating, pivoting, shifting, sliding or otherwise changing the orientation and/or location of one or more of radiating elements 2018. Alternatively or additionally, processor 2030 may be configured to regulate one or more field adjusting elements located in the energy application zone, in order to change the field pattern in the zone.

[00137] In some embodiments, apparatus 100 may involve the use of at least one source configured to deliver electromagnetic energy to the energy application zone. By way of example, and as illustrated in Fig. 4, source 2011may include one or more of a power supply 2012 configured to generate electromagnetic waves that carry electromagnetic energy. For example, power supply 2012 may be a magnetron configured to generate high power microwave waves at a predetermined wavelength or frequency. Alternatively, power supply 2012 may include a semiconductor oscillator, such as a voltage controlled oscillator, configured to generate AC waveforms (e.g., AC voltage or current) with a constant or varying frequency. AC waveforms may include sinusoidal waves, square waves, pulsed waves, triangular waves, or another type of waveforms with alternating polarities. Alternatively, source 2011 may include any other power supply, such as electromagnetic field generator, electromagnetic flux generator, solid-state amplifiers, or any mechanism for generating vibrating electrons.

[00138] In some embodiments, apparatus 100 may include a phase modulator which may be controlled to perform a predetermined sequence of time delays on an AC waveform, such that the phase of the AC waveform is increased by a number of degrees (e.g., 10 degrees) for each of a series of time periods. In some embodiments, processor 2030 may dynamically and/or adaptively regulate modulation based on feedback from the energy application zone. For example, processor 2030 may be configured to receive an analog or digital feedback signal from detector 2040, indicating an amount of electromagnetic energy received from cavity 10, and processor 2030 may dynamically determine a time delay at the phase modulator for the next time period based on the received feedback signal.

[00139] In some embodiments, apparatus 100 may include a frequency modulator. The frequency modulator may include a semiconductor oscillator configured to generate an AC waveform oscillating at a predetermined frequency. The predetermined frequency may be in association with an input voltage, current, and/or other signal (e.g., analog or digital signals). For example, a voltage controlled oscillator may be configured to generate waveforms at frequencies proportional to the input voltage.

[00140] Processor 2030 may be configured to regulate an oscillator to sequentially generate AC waveforms oscillating at various frequencies within one or more predetermined frequency bands. In some embodiments, a predetermined frequency band may include a working frequency band, and the processor may be configured to cause the supply of energy at frequencies within a sub-portion of the working frequency band. A working frequency band may be a collection of frequencies selected because, in the aggregate, they achieve a desired goal, and there is diminished need to use other frequencies in the band if that sub-portion achieves the goal. Once a working frequency band (or subset or sub-portion thereof) is identified, the processor may sequentially apply power at each frequency in the working frequency band (or subset or sub-portion thereof). This sequential process may be referred to as "frequency sweeping." In some embodiments, each frequency may be associated with a feeding scheme (e.g., a particular selection of MSEs). In some embodiments, based on the feedback signal provided by detector 2040, processor 2030 may be configured to select one or more frequencies from a frequency band, and regulate an oscillator to sequentially generate AC waveforms at these selected frequencies. Detector 2040 may include a coupler, e.g., a dual directional coupler.

[00141] Alternatively or additionally, processor 2030 may be further configured to regulate amplifier 2016 to adjust amounts of energy delivered via radiating elements 2018, based on the feedback signal. Consistent with some embodiments, detector 2040 may detect an amount of energy reflected from the energy application zone and/or energy transmitted at a particular frequency, and processor 2030 may be configured to cause the amount of energy supplied at that frequency to be low when the reflected energy and/or transmitted energy is low. Additionally or alternatively, processor 2030 may be configured to cause one or more antennas to supply energy at a particular frequency over a short duration when the reflected energy is low at that frequency.

[00142] In some embodiments, the apparatus may include more than one EM energy generating component. For example, more than one oscillator may be used for generating AC waveforms of differing frequencies. The separately generated AC waveforms may be amplified by one or more amplifiers. Accordingly, at any given time, radiating elements 2018 may be caused to simultaneously emit electromagnetic waves at, for example, two differing frequencies to cavity 10.

[00143] Processor 2030 may be configured to regulate a phase modulator in order to alter a phase difference between two electromagnetic waves supplied to the energy application zone. In some embodiments, the source of electromagnetic energy may be configured to supply electromagnetic energy in a plurality of phases, and the processor may be configured to cause the transmission of energy at a subset of the plurality of phases. By way of example, the phase modulator may include a phase shifter. The phase shifter may be configured to cause a time delay in the AC waveform in a controllable manner within cavity 10, delaying the phase of an AC waveform anywhere from between 0-360 degrees. [00144] In some embodiments, a splitter may be provided in apparatus 100 to split an AC signal, for example generated by an oscillator, into two AC signals (e.g., split signals). Processor 2030 may be configured to regulate the phase shifter to sequentially cause various time delays such that the phase difference between two split signals may vary over time. This sequential process may be referred to as "phase sweeping." Similar to the frequency sweeping described earlier, phase sweeping may involve a working subset of phases selected to achieve a desired energy application goal.

[00145] The processor may be configured to regulate an amplitude modulator in order to alter amplitude of at least one electromagnetic wave supplied to the energy application zone. In some embodiments, the source of electromagnetic energy may be configured to supply electromagnetic energy in a plurality of amplitudes, and the processor may be configured to cause the application of energy at a subset of the plurality of amplitudes. In some embodiments, the apparatus may be configured to supply electromagnetic energy through a plurality of radiating elements, and the processor may be configured to supply energy with differing amplitudes simultaneously to at least two radiating elements.

[00146] Although Fig. 4 and Figs. 2A and 2B illustrate circuits including two radiating elements (e.g., antennas 210, 220 or 2018), it should be noted that any number of radiating elements may be employed, and the circuit may select combinations of MSEs through selective use of radiating elements. By way of example only, in an apparatus having three radiating elements A, B, and C, amplitude modulation may be performed with radiating elements A and B, phase modulation may be performed with radiating elements B and C, and frequency modulation may be performed with radiating elements A and C. In some embodiments, amplitude may be held constant and field changes may be caused by switching between radiating elements and/or subsets of radiating elements. Further, radiating elements may include a device that causes their location or orientation to change, thereby causing field pattern changes. The combinations are virtually limitless, and the invention is not limited to any particular combination, but rather reflects the notion that field patterns may be altered by altering one or more MSEs.

[00147] Some or all of the forgoing functions and control schemes, as well as additional functions and control schemes, may be carried out, by way of example, using structures such as the electromagnetic energy application subsystems schematically depicted in Fig. 1 or Fig. 4. Within the scope of the invention, alternative structures might be used for accomplishing the functions described herein, as would be understood by a person of ordinary skill in the art, reading this disclosure.

[00148] Fig. 5 represents a method for applying electromagnetic energy to an object in accordance with some embodiments of the present invention. Electromagnetic energy may be applied to an object, for example, through at least one processor implementing a series of steps of method 500 of FIG. 5.

[00149] In certain embodiments, method 500 may involve controlling a source of electromagnetic energy (step 510). A "source" of electromagnetic energy may include any components that are suitable for generating electromagnetic energy. By way of example only, in step 510, the at least one processor may be configured to control electromagnetic energy application subsystem 96, e.g. by controlling or power supply 2012, modulator 2014, and/or amplifier 2016.

[00150] The source may be controlled to supply electromagnetic energy at a plurality of MSEs (e.g., at a plurality of frequencies and/or phases and/or amplitude etc.) to at least one radiating element, such as is indicated in step 520. Various examples of MSE supply, including sweeping, as discussed earlier, may be implemented in step 520. Alternatively or additionally, other schemes for controlling the source may be implemented so long as that scheme results in the supply of energy at a plurality of MSEs. The at least one processor may regulate subsystem 96 to supply energy at multiple MSEs to at least one transmitting radiating element (e.g., antenna 102). Additionally or alternatively, other schemes for controlling the source may be implemented. [00151] In certain embodiments, the method may further involve determining a value indicative of energy absorbable by the object at each of the plurality of MSEs, in step 530. An absorbable energy value may include any indicator-- whether calculated, measured, derived, estimated or predetermined - of an object's capacity to absorb energy. For example, computing subsystem 92 may be configured to determine an absorbable energy value, such as a dissipation ratio associated with each MSE.

[00152] In certain embodiments, the method may also involve adjusting an amount of electromagnetic energy incident or delivered at each of the plurality of MSEs based on the absorbable energy value at each MSE (step 540). For example, in step 540, at least one processor may determine an amount of energy to be supplied (or delivered) at each MSE, as a function of the absorbable energy value associated with that MSE. In some embodiments, such determination may be carried out in parallel and/or in sequence at differing height locations along the waterfall. Optionally, the determination at one location along the waterfall is independent of the determination at another location along the waterfall. Similarly, it is optional that energy application at one height location along the waterfall is independent of energy application at another height location along the waterfall.

[00153] In some embodiments, a choice may be made not to use all possible MSEs. For example, a choice may be made not to use all possible frequencies in a working band, such that the emitted frequencies are limited to a sub band of frequencies, for example, where the Q factor in that sub band is smaller or higher than a threshold. Such a sub band may be, for example 50 MHz wide 100 MHz wide, 150 MHz wide, or even 200 MHz wide or more.

[00154] In some embodiments, the at least one processor may determine a weight, e.g., power level, used for supplying the determined amount of energy at each MSE, as a function of the absorbable energy value. For example, amplification ratio of amplifier 2016 may be changed inversely with the energy absorption characteristic of object 11 at each MSE. In some embodiments, when the amplification ratio is changed inversely with the energy absorption characteristic, energy may be supplied for a constant amount of time at each MSE. Alternatively or additionally, the at least one processor may determine varying durations at which the energy is supplied at each MSE. For example, the duration and power may vary from one MSE to another, such that their product correlates (e.g., inversely correlates or otherwise correlates) with the absorption characteristics of the object. In some embodiments, the controller may use the maximum available power at each MSE, which may vary between MSEs. This variation may be taken into account when determining the respective durations at which the energy is supplied at maximum power at each MSE. In some embodiments, the at least one processor and/or controller (e.g., controller 101) may determine both the power level and time duration for supplying the energy at each MSE.

[00155] In certain embodiments, the method may also involve applying and/or supplying electromagnetic energy at a plurality of MSEs (step 550). Respective weights are optionally assigned to each of the MSEs to be transmitted (step 540) for example based on the absorbable energy value (as discussed above). Electromagnetic energy may be supplied to cavity 10 or 200 via antennas, e.g., antenna 102, 210, 220, or 2018. In some embodiments, MSEs may be swept sequentially, e.g., across a range of cavity's resonance MSEs or, along a portion of the range.

[00156] Energy application may be interrupted periodically (e.g., several times a second) for a short time (e.g., only a few milliseconds or tens of milliseconds). During the interruption, it may be determined if variables should be re-determined and reset in step 580. If not (step 580: no), the process may return to step 550 and continue application of electromagnetic energy. Otherwise (step 580: yes), the process may return to step 520 and determine new variables. For example, after a time has lapsed, the solution entering the energy application zone may have different properties; which may or may not be related to the electromagnetic energy transfer. Such changes may include changes in temperature, solute concentration and/or composition, volume, shape and/or dimension of cross-section, flow rate, etc. Therefore, at times, it is desirable to change the variables of transmission. The new variables that may be determined may include: a new set of MSEs, an amount of electromagnetic energy incident or delivered at each of the plurality of MSEs, weight, e.g., power level, of the MSE(s) and duration at which the energy is supplied at each MSE. Consistent with some of the presently disclosed embodiments, the number of MSEs swept in stops during energy application is set to a required minimum, such that the energy application process is interrupted for a minimum amount of time.

[00157] The present invention is not limited to method 500 for applying electromagnetic energy to an object. Within the scope of the invention, alternative methods might be used for accomplishing the functions described herein, as would be understood by a person of ordinary skill in the art, reading this disclosure.

[00158] In some embodiments, the systems and methods described above may be used to apply electromagnetic energy to concentrate a solution, for example, brine or any other solution including a solvent and a solute. Concentrating a solution may result in a solution having a higher solute concentration. For example, as an illustration, concentrating a solution containing lOg/l solute may result in a solution containing 20g/l solute. Concentrating may be performed by evaporating or otherwise reducing the amount of solvent in the solution. For example, by evaporating a portion of the solvent of a solution, more solute per solvent quantity may be left in the solution.

[00159] In some embodiments, separation of solids from a solution may be performed with apparatus and methods consistent with the invention. When the concentration of the solution reaches saturation concentration, solid solute may form in the liquid solution. Further solvent evaporation of a saturated solution does not increase the concentration of the dissolved solute, but rather forms more solid precipitate. Nevertheless, solvent removal from a saturated solution may be considered as concentrating the solution, consistent with this disclosure. [00160] By way of an example, Fig. 6 depicts a solution concentration apparatus 600, which may include a water desalination apparatus, using a single radiating element (e.g. a single RF antenna) and vacuum pump to obtain solid dry precipitate, for example, salt, in accordance with some embodiments of the present invention. In the following, the embodiment of Fig. 6 is described in reference to water desalination, but it may be used for concentrating solutions other than brine, for example grey water, soapy water, antifreeze (water with ethylene glycol), toxic solutions, etc. Furthermore, the invention is not limited to solutions wherein the solvent is water. For example, in some embodiments, the solution may include polycyclic aromatic hydrocarbons (PAH) in oil, acid (e.g. H2SO4) in ether, barium salts in methanol, cyanides and crown ether cyanide adducts in alcohols and/or in glycols, and/or polychlorinated biphenyl (PCB) in organic polar and non-protic solvent(s). In the embodiment depicted in Fig. 6, a pump 602 may drive a solution (e.g., brine, for example, sea water), from an inlet 601 into a chamber 606 via a brine feeding pipe 619. In some embodiments, the brine may fall essentially vertically inside at least a part of chamber 606 to form a waterfall 613, such that the contact between waterfall 613 and walls of chamber 606 is minimized. In certain embodiments, substantially all of the flow of the waterfall 613 may be spaced apart from interior walls of chamber 606. Waterfall 613 is shown in the figure as getting thinner at lower height locations to illustrate that portions of the water evaporate and less water remains in the waterfall. The dots at the lowest portion of the waterfall may symbolize solid particles that fall to the bottom of chamber 606.

[00161] In some embodiments, the brine may be introduced into chamber 606 as drops or droplets, which are sufficiently heavy to fall down , but small enough to enlarge the surface area of the water to enhance evaporation, and possibly also to fall down more slowly than larger drops. Drops or droplets may be obtained by nozzles configured for spraying solution at a target droplet size and/or by mixing the solution with an appropriate propellant or vaporizer. [00162] In some embodiments, forming a waterfall may include providing the solution into the chamber via a conduit that is substantially narrower than the chamber, and along a central axis of the chamber. In some embodiments, forming a waterfall may include forming droplets. This may be achieved, for example, using a two-fluid nozzle: one of the fluids is the solution, and the other is air or other gas. In some embodiments, the nozzle may be an ultrasonic nozzle, configured to produce from the solution a spray of droplets of the appropriate size.

[00163] In some embodiments, the pressure inside chamber 606 may be controlled, for example, by vacuum pump 605.

[00164] In some embodiments, chamber 606 may form an energy application zone. For example, chamber 606 may have RF transparent walls, and RF antennas configured to irradiate the waterfall with RF radiation may be located on a side of the RF transparent walls opposite to the waterfall. One such embodiment is illustrated in Fig. 7. As shown in Fig. 6, an RF antenna 607 may be located within feeding pipe 619 and/or within the flow of brine and may protrude into waterfall 613. RF antenna 607 may be protected from contact with the solution, for example, by an RF-transparent coating (not shown). The coating may be made, for example, of Teflon, polyethylene, polystyrene, low-loss mica, and/or low-loss Pyrex. An RF generator 608 may be connected to antenna 607 and may be configured to supply energy to antenna 607. RF generator 608 may include, included in, or be congruent with source 2011 depicted in Fig. 4. RF generator 608 may be controlled by a controller 609 such that RF radiation emitted into chamber 606 and the waterfall is substantially absorbed by the water and causes a sufficient temperature rise in the waterfall to create evaporation. Controller 609 may include, be included in or be congruent with processor 2030 and/or controller 101.

[00165] In some embodiments, an electromagnetic (EM) field excited by the RF radiation may be controlled to increase evaporation efficiency. Evaporation efficiency may refer to a parameter that represents a relationship between an amount of energy transferred to a solution and an amount of solvent evaporated from the solution. For example, evaporation efficiency may be determined, for example, by comparing an amount of RF energy (radiation) supplied to an amount of solvent evaporated. Evaporation efficiency may depend, for example, upon the absorption efficiency of the RF energy in the waterfall; the size of the droplets; the pressure in the chamber; the partial pressure of the solvent in the chamber; and/or the efficiency of solvent evacuation from the chamber. For example, the brine in the waterfall may have different solute concentrations at different height locations along the waterfall, as water evaporates from the falling brine. That is, the salt (or other type of solute) concentration at a first, lower height location along the waterfall may be higher than the concentration at a second, higher height location. Different electromagnetic fields may be excited at different height locations along the waterfall, e.g. to compensate for differences in dielectric responses caused, for instance, by changing concentration in the waterfall of solution. Alternatively or additionally, an electromagnetic field with varying intensity at different height locations along the waterfall may be excited, e.g. to compensate for differences in dielectric responses caused, for instance, by changing concentration in the waterfall of solution.

[00166] For example, electromagnetic fields may be tailored or controlled to concentrate at an outer layer of the waterfall, from which evaporation may occur most efficiently. For example, the RF radiation may concentrate on the outer surface of the waterfall to generate a sufficient amount of heat to cause evaporation. Selectively evaporating an outer layer of water can minimize energy loss by avoiding significant heating of inner layers of water, which do not evaporate even when heated. By the time the inner layers become outer layers, the salt concentration therein may have changed, and electromagnetic radiation of other characteristics may be applied to evaporate water from the waterfall.

[00167] In some embodiments, the electromagnetic radiation applied to the chamber to evaporate water from the brine may be controlled to improve or even maximize evaporation efficiency or reach efficiency within a range of target values. For example, a device that evaporates a certain amount of a solvent from a given solution at given conditions, consuming only the amount of energy required theoretically for evaporating the certain amount of solvent from the given solution at the given conditions, may be considered substantially 100% efficient. For example, theoretically, the amount of heat required for evaporating 1kg of clean water at room temperature is 0.7kW-h. Therefore, a system that uses 0.7kW-h to evaporate 1kg of clean water at room temperature works at substantially 100% efficiency. In some embodiments, the electromagnetic radiation may be controlled to cause evaporation at 90% efficiency or more, 95% or more, or 99% or more. In other embodiments, the efficiency may be lower, for example, at least 75% or at least 50%.

[00168] In some embodiments, the excited electric field may be tailored or controlled by applying one or more MSEs. For example, the intensity of RF radiation may be adjusted using a particular set of MSEs. In some embodiments, these sets of MSEs may be chosen based on absorption characteristics of the solution (for example its dielectric properties), and the power level of the radiation supplied at each of these MSEs may also be chosen according to the absorption characteristics. For example, a particular set of MSEs may include MSEs that, in some embodiments, offer energy absorbance levels over a predetermined threshold or, in other embodiments, result in energy absorbance levels below a predetermined threshold. In other embodiments, the selected set of MSEs can provide varying levels of energy absorbability. In some embodiments, the power level associated with a particular MSE can be selected based on the absorbability of the radiation resulting from the MSE. For example, in some embodiments, MSEs with relatively low energy absorbability values may be supplied with higher power levels, and MSEs with relatively high energy absorbability values may be supplied with lower power levels. In still other embodiments, MSEs with relatively high energy absorbability values may be supplied with higher power levels, and MSEs with relatively low energy absorbability values may be supplied with lower power levels. [00169] In some embodiments, the amounts of energy to be provided at various MSEs may be determined periodically during operation to compensate for changes in, e.g., the composition, temperature, or an amount of water in a certain portion of the waterfall. The amount of energy provided at a particular MSE or energy delivery scheme may be controlled by controlling power and/or time at which energy is provided at the particular MSE or at each of the MSEs participating in the energy delivery scheme.

[00170] In some embodiments, the set of MSEs may include one dimensional MSEs for which only one parameter (e.g., frequency) varies. In other embodiments, the set of MSEs may include multi-dimensional MSEs for which more than one parameter (e.g., two or more of frequency, phase (e.g., between two EM waves provided to the waterfall, or between an EM wave provided by an antenna and a reflective element in the chamber), or intensity difference (e.g., between two antennas that simultaneously provide EM energy to the same volume portion of the chamber)) can vary.

[00171] In some embodiments, the modulation space may be sampled, and the dielectric reaction of brine of a particular concentration may be examined at each MSE. Such sampling, also referred to as scanning or sweeping, can allow for determination of the dielectric response of the brine at each of the MSEs and determination of a target amount of energy to be provided at that MSE.

[00172] In some embodiments, a plurality of MSEs may be selected for use in applying energy to a waterfall of solution including a solvent and a solute. These MSEs may each be assigned a particular weight to provide a desired effect. For example, each MSE may excite a particular field pattern in chamber 606, and the total field provided to the chamber may include a combination of the field patterns of the selected MSEs. Weighting the contributions of the selected MSEs can allow for controlling of the field pattern contribution of each MSE and, in turn, the total field in the chamber. [00173] In some embodiments a target energy distribution may be designed to efficiently evaporate water from the brine. This energy distribution may be applied to the chamber by sequentially providing energy at the selected MSEs, such that the overall energy provided is in accordance with a target energy distribution. The weights for each of the selected MSEs to be provided sequentially by RF antenna 607 may be determined by calculation and/or simulation.

[00174] As the solution in waterfall 613 falls, the solution evaporates and becomes increasingly condensed and concentrated. This process of evaporation occurs while the solution remains substantially spaced apart from the walls of chamber 606 and from other similar structural elements. In some embodiments, at the bottom of the waterfall, solid salt may be separated from the solution. In some embodiments, the solid salt can be dried and removed from the chamber. As shown in Fig. 6, salt 614 that reaches the bottom of chamber 606 may be removed by a solid (salt) pump 616 that has arms 618 that rotate to minimize or prevent the formation of scaling on the bottom of the vacuum column. The salt may be collected through an outlet 617 of the salt pump. In some embodiments, salt 614 may be dry and/or dehydrated.

[00175] In some embodiments, the salt may be wet and may constitute part of a saturated solution, which can be removed from the chamber by any suitable method. In some embodiments, the salt does not fully separate, and the solution obtained at the bottom of the waterfall may be more concentrated than higher up on the waterfall, but below saturation. Exemplary concentrations of such a solution may include 30%, 35%, and 40% w/w of total salt concentration. When non- saturated solution collects at the bottom of chamber 606, the solution can be evacuated or, optionally, brought back to the top of the waterfall for additional processing. In some embodiments, the composition obtained at the bottom of the waterfall may be of commercial grade, and may be used in further processes of the chemical industry, thus eliminating the need to discard it. [00176] In some embodiments, in addition to concentrating the brine, the apparatus may collect evaporated water, which may be used, for example, as drinking water, optionally after adding salts in a small amount, as required for drinking. Collecting water vapor may include coupling a vacuum pump to the chamber via a vacuum pipe. For example, as shown in Fig. 6, water vapor 620 generated during RF heating of the waterfall may be moved within chamber 606 by pumping action of the vacuum pump 605 through a vacuum pipe 604. Optionally, vacuum pump 605 controls the pressure in chamber 606 to be below atmospheric pressure, for example, between about 20mmHg and 200 mmHg. When the water vapor passes over condensing coils 610 at the top of chamber 606, the water vapor may condense and drip into collecting pans 611. The condensed water may be collected through pure water pipes 612. Condensing coils 610 may be in thermal contact with heat exchangers (not shown) for using the heat of condensation of the water on the coils to preheat liquid before entering chamber 606.

[00177] Fig. 7 depicts an apparatus 700 for concentrating a solution according to some embodiments of the invention. Apparatus 700 may include a water desalination apparatus. Although apparatus 700 is described below in terms of water desalination, its application is not limited to the desalination of water. For example, it may be used for evaporating solvents from other solutions. Apparatus 700 may include a plurality of RF antennas and hot air circulation to obtain a concentrated solution, in accordance with some embodiments of the present invention. In the embodiments depicted in Fig. 7, a pump 702 may drive brine 701 (or any other type of solution including a solvent and a solute) into chamber 706 via a brine feeding pipe 719 such that a waterfall 713 is formed. RF antennas 707 may be located at the periphery of chamber 706 at different heights along the chamber. Optionally, antennas 707 may be protected from brine 701 in chamber 706 by a wall 711. In some embodiments, wall 711 may be a wall of a waveguide. In some such embodiments, antennas 707 may be slot antennas, which may include slots in wall 711. In some embodiments, wall 711 may be RF transparent. For example, wall 711 may be RF transparent in frequency ranges at which antennas 707 emit. In some embodiments, the transparency of wall 711 is only partial, for example, such that allows sufficient amount of the energy emitted by antennas 707 to participate in the solvent evaporation. In some embodiments, antennas 707 may be located within or substantially within the solution waterfall. Optionally, outer walls 712 of chamber 706 may be made of RF-reflective material, such as, e.g., stainless steel, to return into the chamber radiation that reaches the walls. An RF generator 708 (which may be, for example, included in, congruent with, or include source 2011 depicted in Fig. 4) may be connected to antennas 707 and configured to supply energy to the antennas.

[00178] In some embodiments, all or some of the antennas may be driven by a single generator. Alternatively, in some embodiments, each RF antenna may be driven by its own RF generator. In some embodiments, the antennas can be divided into groups, and each group may be controlled by its own RF generator. For example, a first group of antennas may be driven by a first RF generator and a second group of antennas may be driven by a second RF generator. Optionally, the antennas can be divided into groups, e.g., in accordance with height location along the waterfall, and each group may be controlled by its own controller. Optionally, the various controllers are in communication. A controller 709 may control the RF generator(s) 708 such that the waves emitted into the waterfall evaporate solvent (e.g., water) from the waterfall at efficiency greater than a target threshold; e.g., 50%, 75%, 90%, 95%, or 99%. For example, in some embodiments, a modulation space element for applying the electromagnetic energy can be determined and/or selected such that evaporation efficiency higher than a threshold value is achieved.

[00179] In certain exemplary methods, electromagnetic energy may be applied to the waterfall using multiple modulation space elements. Evaporation efficiencies corresponding to the multiple modulation space elements can be determined, and based on this information, at least one modulation space element corresponding to evaporation efficiency higher than the predetermined threshold value may be selected.

[00180] Using controller 709, for example, each RF antenna can be controlled to apply radiation to the waterfall according to a target energy delivery scheme. For example, in some embodiments, all antennas at all height locations along the waterfall may emit substantially similar radiation. In other embodiments, one or more antennas may emit radiation different from the others. For example, the plurality of antennas can be controlled such that the radiation emitted from the plurality of antennas progressively changes with height location along the waterfall. For example, the radiation intensity may increase between a first point and a second point lower on the waterfall. The radiation intensity may further decrease from the second point to an even lower point on the waterfall. In some embodiments, radiation applied to the waterfall at a first height location may differ in at least one characteristic from electromagnetic radiation applied to the waterfall at a second height location along the waterfall. In some embodiments, this characteristic may correspond to a power level of the emitted radiation. The antennas may be controlled such that a power level associated with the electromagnetic radiation applied at a first height location is lower than a power level associated with electromagnetic radiation applied at a second height location. The second location may be higher or lower than the first location.

[00181] In addition to power level, other characteristics of the emitted radiation may be controlled. For example, the frequency, phase, or any other desired characteristic may be controlled to vary the characteristics of the radiation emitted from the antennas along the height of the waterfall. Radiation can be emitted from all of the antennas simultaneously or radiation may be emitted from the antennas in any desired alternations and/or overlapping of application times. For example, radiation may be applied to the waterfall at a first height location during a first time period that may or may not overlap with a second time period during which electromagnetic radiation is applied to the waterfall at a second height location. Optionally, radiation is applied at the first height by a first antenna, and at the second height by a second antenna, different from the first.

[00182] Characteristics of the radiation provided by the antennas can be varied based on observed properties of the waterfall of solution. Consistent with the disclosure, an observed property of the waterfall of solution may be any characteristic associated with the waterfall of solution that may be directly or indirectly measured, sensed, observed, or determined using one or more sensors or instruments. In some embodiments, observed properties of the waterfall may be determined through visual inspection.

[00183] In some embodiments, an absorption rate (i.e., an observed property) at a plurality of height locations along the waterfall may be determined in order to provide a set of energy absorption rates. Based on these energy absorption rates, amounts of electromagnetic energy applied at one or more height locations along the waterfall can be controlled. In some embodiments, a plurality of modulation space elements for applying electromagnetic energy may be selected based on the absorption rate information, which may include, for example, one or more values indicative of energy absorbable in the waterfall, and energy may be applied in sequence, simultaneously, or in accordance with some other desired pattern at each of the modulation space elements.

[00184] In some embodiments, the radiation provided by the antennas can be varied based on the solute concentration of the waterfall. For example, radiation power levels, frequency, phase, intensity, etc. may be selected based on solute concentration and how that concentration may vary with height location along the solution waterfall.

[00185] In some embodiments, a dry air system may be used to collect water vapor. Dry air may include any air drier than air located inside the chamber. Preferably, this dry air may be dry enough to absorb water vapor evaporating from the waterfall without becoming saturated. In some embodiments, dry air may flow into chamber 706 at a rate about the same as a flow rate of wet air flowing out of the chamber after absorbing water vapor from the evaporating waterfall. With such an arrangement, the pressure in the chamber can remain substantially constant. Alternatively, air may be pumped out faster than pumped in, in which case the pressure in the chamber may drop, and this may increase evaporation. After the pressure drops, the rates of pumping out and pumping in may be made equal, and a lower pressure may be maintained. For example, a pressure below atmospheric pressure may be maintained, and thus allow using less EM energy for evaporation than would be required at atmospheric pressure. For example, the pressure may be maintained at a range of between about 20mmHg and about 200mmHg. In some embodiments, for example, when the evaporated solvent is other than water, the dry air may be replaced with another gas that is capable of absorbing vapor of the solvent.

[00186] Thus, in some embodiments, dry air 720 may be pumped into chamber 706 through dry air inlet 722 with air inlet pump 724. Air may be pumped out of chamber 706 through air outlet 726. Optionally, the air may be fed into a dryer 729, from which the air is redirected to air inlet 722. Optionally, dryer 729 contacts the air with molecular sieves or other suitable chemical desiccant to dry the air flow. This desiccant or other type of drying element may then be heated, optionally, by F radiation, to maintain its drying ability. In some embodiments, the desiccant may be dried using heat obtained from water condensation on condensation coils 710.

[00187] In some embodiments, the dry air inlet 722 may be located at the bottom of chamber 706. Additionally or alternatively, dry air inlets may be provided at higher points along chamber 706. The dry air may be provided into chamber 706 such that the dry air efficiently contacts vapor from the chamber. Through contact, this vapor wets the dry air, such that wet, even saturated, air reaches the condensing coils 710 at the top of the chamber, where the vapor is condensed and generates pure water that can be collected in collecting pans 11. The pure water may be evacuated for further use by pure water pipes 12. Air, which is dryer than the air that reached the condensing coils 710, may be pumped out of chamber 706 via air outlet 726 and pipe 704 via pump 705. Some of the water vapor may condense on the walls. This is particularly so in embodiments where the radiation selectively heats the solution, leaving the walls cooler than the solution. Water that condenses on the walls may be used for washing the walls of accumulated residue, which might get to the walls, for instance, with spray from the waterfall. In some embodiments, some of the water collected in collecting pans 11 is piped through a tube 13, which may go along the periphery of the internal walls of chamber 706. In some embodiments, tube 13 (or a plurality of similar tubes) may go along the periphery of the entire walls. Tube 13 may have openings (not shown) to drip water on the walls to clean it from salt, which might get to the walls, for example, via spray from the waterfall.

[00188] Concentrated salt solution 730 reaching the bottom of chamber 706 may be removed by a concentrated brine pump 716. Optionally, arms 719 may be rotated at the bottom of chamber 706 to prevent accumulation of solid salt on the bottom of the chamber.

[00189] In some embodiments, the brine that enters the waterfall may be supplied from the output of another desalination apparatus, for example, a reverse osmosis apparatus, or any other type of desalination apparatus, for example, multi stage flash (MSF) distillation apparatus or multi effect distillation (MED) desalination apparatus. Thus, in some embodiments, a desalination system may include an existing first desalination device and a second desalination device in accordance with embodiments of the present invention, for example, with an apparatus as shown in Fig. 6 or in Fig. 7. The second device may receive from the first device brine in concentrations that the first device does not treat, for example, to avoid scale buildup in the first device, or for any other reason.

[00190] For example, Fig. 8 is a diagrammatic illustration of such a desalination system (800), in accordance with some embodiments of the present invention. System 800 may include a first desalination apparatus 802, for example, a reverse osmosis apparatus, and may also include a second desalination apparatus 804, as described above, for example. Brine of a first concentration (e.g., sea water) may enter apparatus 802 through inlet 810, and desalinated water may leave device 802 through outlet 812. Brine of a second concentration, higher than the first concentration may leave device 802 via outlet 814.

[00191] In system 800, brine from outlet 814 may enter apparatus 804 through inlet 820. Pure water may leave device 804 through outlet 822, where a waterfall 825 is formed of the solution and irradiated with electromagnetic energy, and brine of a third concentration, higher than the second concentration, may leave device 804 via outlet 824. The brine of the third concentration may be collected in vessels 826 for further use, for example, in chemical synthesis reactions. Waterfall 825 is depicted as a plurality of separate drops, but may have any other suitable forms.

[00192] In some embodiments, the output of the first apparatus may be correlated with the input of the second apparatus. For instance, the second apparatus may be pre-tuned to treat brines of concentrations and/or temperatures that are typical to the output of the first apparatus. In some embodiments, such correlation may be updated during operation. For example, the concentration of the brine leaving the first apparatus may be monitored, and the RF radiating elements of the second apparatus may be tuned accordingly. In some embodiments, the second device may also be tuned to receive amounts of brine in accordance with the amounts of output brine delivered by the first device.

[00193] As shown in Fig. 8, brine going from outlet 814 may be monitored with a monitor 830. The brine may be monitored for salt concentration, temperature, RF absorbance at one or more frequencies, dielectric properties, or any other observed properties of the waterfall of solution. The value(s) of the measured characteristic(s) may be communicated to a controller, e.g. controller 609 (shown in Fig. 6) or controller 709 (shown in Fig. 7), to control antenna(s), e.g. antennas 607 or 707, to emit RF radiation in accordance with the measured value(s). The controller may include a memory for storing values indicative of RF radiation patterns for use with various initial brine concentrations, temperatures, or other characteristics. Additionally or alternatively, the controller may select an appropriate field pattern or energy delivery scheme to be applied by antenna(s) 607 or 707.

[00194] Fig. 9 is a graphical representation of calculation results for a Mie scattering cross section Q as a function of the frequency. In some embodiments, Q. may be a primary factor used for determining the absorbance of RF radiation by a brine droplet. For example, Q. is given approximately by the equation:

Q(p) = 2 - (4/p) sin(p) + (4/p²) ( 1- cos(p) ) where p = (4 π a / λ) (\/ε' - 1), a is a radius of a sphere modeling a brine droplet, ε' is a dielectric constant inside the sphere (e.g., ~80 for distilled water), and λ is an incident wavelength (λ = c//, where / is the frequency and c is the speed of light). According to the Mie scattering theory, p represents a phase delay through the center of the sphere.

[00195] The curves shown in Fig. 9 include calculations representative of absorption by brine droplets having a radius of 3mm, and different concentrations of NaCI (1, 3, and 5 Molar (M), corresponding to about 6%, 16%, and 25% w/w, respectively). As shown in Fig. 9, the maximal absorption is expected to be at 4.65 GHz when the concentration is 1M (circled line), 5.47GHz when the concentration is 3M (crossed line), and 5.96GHz when the concentration is 5M (dotted line). Thus, adjusting the frequency of the incident electromagnetic waves provided by the RF generator to irradiate higher frequencies at lower points along the waterfall may increase the efficiency in relation to using a single frequency at all points along the waterfall.

[00196] In the foregoing Description of Exemplary Embodiments, various features are grouped together in a single embodiment for purposes of streamlining the disclosure. This method of disclosure is not to be interpreted as reflecting an intention that the claimed invention requires more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive aspects lie in less than all features of a single foregoing disclosed embodiment. Thus, the following claims are hereby incorporated into this Detailed Description, with each claim standing on its own as a separate embodiment of the invention.

[00197] Moreover, it will be apparent to those skilled in the art from consideration of the specification and practice of the present disclosure that various modifications and variations can be made to the disclosed systems and methods without departing from the scope of the invention, as claimed. For example, one or more steps of a method and/or one or more components of an apparatus or a device may be omitted without departing from the scope of the invention. Thus, it is intended that the specification and examples be considered as exemplary only, with a true scope of the present disclosure being indicated by the following claims and their equivalents.

[00198] As used herein, the singular form "a", "an" and "the" include plural references unless the context clearly dictates otherwise. The use of the terms "at least one", "one or more", or the like in some places is not to be construed as an indication to the reference to singular. The terms "comprises", "comprising", "includes", "including", "having" and their conjugates mean "including but not limited to".

Claims

WHAT IS CLAIMED IS:

1. A method for concentrating a solution including a solvent and a solute,

comprising:

forming a waterfall of the solution in a chamber, wherein substantially an entire flow of the waterfall is spaced apart from interior walls of the chamber; and

applying electromagnetic energy to the waterfall for evaporating at least a portion of the solvent.

2. The method of claim 1, further comprising:

controlling application of the electromagnetic energy such that

electromagnetic radiation applied to the waterfall at a first height location differs in at least one characteristic from electromagnetic radiation applied to the waterfall at a second height location along the waterfall.

3. The method of claim 1, further comprising:

controlling application of electromagnetic energy such that different amounts of electromagnetic energy are applied to different height locations along the waterfall according to differences in dielectric responses of the solution at the different height locations.

4. The method of claim 1, comprising applying an electromagnetic field with varying intensity at different height locations along the waterfall according to differences in dielectric response of the waterfall in the different height locations.

5. The method of claim 2, wherein the at least one characteristic includes at least one of a frequency of the electromagnetic radiation, a phase of the

electromagnetic radiation, and an amplitude of the electromagnetic radiation.

6. The method as claimed in claim 1 or claim 2, comprising: determining a set of values, each value indicative of absorbable energy at each of a plurality of height locations along the waterfall to provide a set of values indicative of absorbable energy; and

controlling amounts of electromagnetic energy applied at one or more height locations along the waterfall based on the set of values.

7. The method as claimed in any one of claims 1 to 6, comprising:

determining an energy delivery scheme for applying the electromagnetic energy; and

applying the electromagnetic energy according to the energy delivery

scheme.

8. The method as claimed in claim 7, wherein the energy delivery scheme

comprises a modulation space element, which includes at least one of frequency, phase, and amplitude.

9. The method as claimed in claim 7 or claim 8, wherein determining the energy delivery scheme comprises:

detecting observed properties of the waterfall of solution; anddetermining an energy delivery scheme based on the observed properties of the waterfall of solution.

10. The method as claimed in any of claims 7 to 9, wherein determining the energy delivery scheme comprises:

applying electromagnetic energy to the waterfall using multiple modulation space elements;

determining evaporation efficiencies corresponding to the respective

modulation space elements; and

determining the energy delivery scheme based on the evaporation

efficiencies.

10. The method as claimed in any one of claims 6 to 9, wherein determining the energy delivery scheme comprises: applying electromagnetic energy to the waterfall using multiple modulation space elements;

determining observed properties of the waterfall corresponding to the

respective modulation space elements; and

determining the energy delivery scheme based on the observed properties of the waterfall.

11. The method as claimed in any one of claims 1 to 10, wherein forming the waterfall comprises forming a plurality of droplets of the solution.

12. The method as claimed in any one of claims 1 to 11, wherein applying electromagnetic energy comprises:

applying electromagnetic energy via electromagnetic energy feeds placed at a plurality of height locations along the waterfall, wherein the electromagnetic energy applied at respective height locations has different characteristics.

13. The method as claimed in any one of claims 1 to 12, comprising:

condensing at least some of the evaporated solvent to obtain a liquid solvent; and

washing the walls of the chamber with the obtained liquid solvent.

14. The method as claimed in any one of claims 1 to 13, further comprising collecting vapor of the solvent.

15. The method as claimed in claim 14, wherein collecting the vapor comprises: providing gas to the chamber to absorb vapor; and

transferring gas out of the chamber.

16. The method as claimed in any one of claims 1 to 15, wherein the solution is corrosive to the interior walls of the chamber.

17. The method as claimed in any one of the preceding claims, comprising controlling a pressure in the chamber such that the pressure is below atmospheric pressure.

18. The method of claim 17, wherein the pressure is between 20mmHg and 200mmHg.

19. An apparatus for concentrating a solution including a solvent and a solute, comprising:

a chamber configured to house a waterfall of the solution, wherein

substantially an entire flow of the waterfall is spaced apart from interior walls of the chamber; and

an electromagnetic source configured to apply electromagnetic energy to the waterfall for evaporating at least a portion of the solvent.

20. The apparatus of claim 19, further comprising a controller configured to control the application of electromagnetic energy along the waterfall such that

21. The apparatus of claim 20, wherein the controller is configured to control the application of electromagnetic energy along the waterfall such that different amounts of electromagnetic energy are applied to different height locations along the waterfall.

22. The apparatus of claim 21, wherein the differing amounts of electromagnetic energy differ according to differences in dielectric responses of the solution at the different height locations.

23. The apparatus of claim 20, wherein the controller is configured to control application of electromagnetic energy along the waterfall such that electromagnetic field with varying intensity is applied at different height locations along the waterfall according to differences in dielectric response of the waterfall in the different height locations.

24. The apparatus as claimed in any one of claims 19 to 23, further comprising a nozzle configured to introduce the solution into the chamber as a plurality of droplets.

25. The apparatus as claimed in any one of claims 19 to 24, wherein the

electromagnetic source further comprises:

a plurality of electromagnetic energy feeds positioned at a plurality of height locations along the waterfall.

26. The apparatus as claimed in any one of claims 19 to 25, further comprising one or more electromagnetic energy feeds positioned within the waterfall.

27. The apparatus as claimed in any one of claims 19 to 26, further comprising a vapor collector configured to:

provide dry air into the chamber for absorbing vapor of the solution; and transfer air out of the chamber.

28. The apparatus as claimed in any one of claims 19 to 27, comprising

a heat exchanger configured to condense vapor obtained from the solution; and

a collecting vessel configured to collect vapor condensed on the heat exchanger.

29. The apparatus as claimed in any one of claims 19 to 28, comprising a pipe going along at least a portion of the interior walls of the chamber, the pipe having openings for dripping a washing liquid on the interior walls to wash the interior walls.

30. The apparatus as claimed in any one of claims 19 to 29, wherein the washing liquid includes a portion of the evaporated solvent condenses on the interior walls.

31. The apparatus as claimed in any one of claims 19 to 30, wherein the interior walls of the chamber are susceptible to corrosion by the solution.

32. A system for concentrating a solution, comprising:

a first apparatus for concentrating the solution to a first solution having a first solute concentration, wherein the first solution includes a solute and a solvent; and

a second apparatus, configured to receive the first solution from the first apparatus, for concentrating the first solution,

wherein the second apparatus is according to any one of claims 19 to 31.