Patent Publication Number: US-2011048038-A1

Title: Multipurpose adiabatic potable water production apparatus and methods

Description:
This application claims the benefit of U.S. Provisional Application Ser. No. 60/800,358, filed May 15, 2006 and incorporates that application herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     My invention relates to an improved apparatus for transforming atmospheric water vapor, or non-potable water vapor vaporized into air, into potable water, and particularly for obtaining drinking quality water through the formation of condensed water vapor upon one or more surfaces which are maintained at a temperature at or below the dew point for a given ambient condition. The surfaces upon which the water vapor is condensed are kept below the dew point by means of a refrigerant medium circulating through a closed fluid path, which includes refrigerant evaporation apparatus, thereby providing cooling of a bypassing airstream, and refrigerant condensing apparatus for providing heat to the airstream in an appropriate region so as to increase the capacity of the air to carry water vapor (i.e. increased humidity). 
     U.S. Pat. No. 5,301,516—Poindexter and U.S. Pat. Nos. 5,106,512 and 5,149,446—Reidy each disclose potable water collection apparatus comprising refrigeration apparatus to maintain a cooling coil at a temperature below the dew point to cause condensed water to form. Other prior art examples include U.S. Pat. No. 5,669,221—Le Bleu and Forsberg, wherein collected water or municipal water is simply filtered repeatedly until a desired potable quality exists. Other prior art examples for converting water vapor into liquid potable water exist within the public domain. U.S. Pat. No. 6,343,479—Merritt and U.S. Published Application No. 20050262854, now U.S. Pat. No. 7,121,101—Merritt, also disclose advantageous techniques for extracting water from air. 
     Much of the above mentioned prior art of others is limited in scope to performing air to water conversion, thereby exhibiting an undesirable shortcoming. That prior art typically exhibits an inability to efficiently convert into water any quantity near the total amount of water vapor actually present in the atmosphere in the vicinity of surfaces maintained at temperatures below the dew point. The novel water production systems and methods disclosed herein are further capable of performing multiple functions such as water purification, desalination and distillation, as well as the task of converting moist air to water. The systems and methods disclosed herein will provide multiple functions at a substantial increase in efficiency with respect to the conventional techniques used for these functions, thereby overcoming shortcomings of the prior art and providing a much sought after solution to water quality problems which exist worldwide. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide novel means and methods for condensing and collecting water for drinking purposes from the atmosphere. It is a further object of the invention to provide means to purify water not yet fit for human consumption, thereby rendering the water safe to drink. It is yet a further object of the present invention to provide means and methods to distill ordinary water at relatively low ambient temperatures, thereby substantially reducing the energy costs normally associated with this task. These and other objects are fulfilled by employing sophisticated refrigeration techniques including such things as multiple evaporators, adiabatic cooling techniques, reheat, as well as a novel defrost mechanism, all operating within a ducted air passageway. These techniques allow the apparatus to capture relatively large quantities of water, up to the greatest quantity of moisture per unit volume of air possible under a variety of conditions and situations. Upon determining whether the apparatus is to function as a simple air to water conversion device, a water distillation device, or desalination device, controls relevant to each separate operation may be activated in accordance with certain aspects of the present invention. 
     In accordance with one aspect of this invention, a method and apparatus for providing low temperature water distillation is as follows. A fan forces air through an air passage duct which is formed to allow for a continuous circulation pattern. The air duct or passageway preferably is insulated from exterior ambient temperature conditions. Water is introduced into the circulating air in the form of a fine mist which has an immediate effect known as adiabatic cooling. In this case, the adiabatic process is evaporative cooling. As the water vapor is absorbed into the air, energy is transformed from sensible heat into latent heat of vaporization. Accordingly, the temperature of the air falls, and its absolute humidity rises, while the overall energy content remains the same. The vapor laden air is then driven by the fan and passed across at least one surface of a first air stream cooling element which is maintained at a temperature below the dew point. The first cooling element causes a portion of the vapor in the air to convert into liquid water. As the air passes the first cooling element, it is cooled to reach one hundred percent relative humidity. The air stream is then passed across the surface of a second air stream cooling element. The second cooling element is operated at a temperature at or below the freezing point of water so that a very substantial percentage of the remaining water within the air stream is captured at the second cooling element. As the air stream passes beyond the second cooling element, it is again at one hundred percent relative humidity, though at a much cooler temperature. The air stream is then passed across an air stream heating element where the temperature of the air is drastically increased, simultaneously resulting in a significant drop in relative humidity. The air preferably then returns through the insulated ducted air passageway to the region of the backside of the fan which forces the air through the cycle again. At the same time that the airstream passes around the enclosed passageway in, for example, a counterclockwise direction, a refrigerant is passed around the corresponding loop of refrigerant elements in the opposite direction and the operating conditions associated with the refrigerant are controlled at each element to effect the desired temperature and pressure conditions. 
     This arrangement of adiabatic cooling, first and second cooling means, and air reheat, results in the capture of the greatest quantity of water possible in comparison to conventional techniques used for such tasks. Further, the task is accomplished with a significant decrease in energy usage, thereby resulting in higher efficiencies. An adjustable air damper may be positioned in the ducted passageway to control the inlet and exhaust of air into and out of the closed loop, this being determined by the particular function of the device, ambient conditions such as temperature and relative humidity, and pressures within the refrigerant circulating mechanism which control the temperature of the cooling and heating means. In the above described operation the damper is normally closed, isolating the air circuit from exterior ambient conditions. The water formed upon the cooled surfaces is collected and subjected, for example, to a germicidal (e.g., ultraviolet light) lamp or is subjected to injection of ozone into the collected water to eliminate bacteria or other harmful contaminants and is also filtered through activated carbon or other suitable medium to produce potable water. 
     An integrated combination of a contoured condensate collection tray and a principal water storage container molded from a relatively transparent plastic material is particularly suitable for storing potable water and is associated with a first or main evaporator in a primary air cooling apparatus. 
     Auxiliary water storage apparatus, including an auxiliary cooling (evaporator) coil supplied with refrigerant gas from the same compressor as the primary air cooling apparatus, is employed in such a manner that at least a portion of the water collected in the principal container is further cooled for human consumption and, at the same time, the gas temperature at the inlet side of the compressor is lowered and the load on the compressor is reduced so as to improve its operation by combining refrigerant recovered from the auxiliary evaporator coil with that recovered from a main evaporator coil before being returned to the single compressor. 
     The foregoing and other aspects of one or more inventive configurations described herein will be described further below referring to the drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic representation of one embodiment of a water from air recovery system illustrating operational elements and their relative positions. 
         FIG. 2  is a standard psychrometric chart for water, with state points marked by alphabetic characters, illustrating selected information with reference to the detailed description of the system of  FIG. 1 . 
         FIG. 3  is schematic illustration of a section of an embodiment of a system with particular reference to components which control temperatures of first and second cooling elements. 
         FIG. 4  is a schematic representation of an alternate embodiment of a system illustrating air cooled de-superheating means. 
         FIG. 5  is a schematic representation of a system similar in certain respects to that described in U.S. Pat. No. 6,343,479 of Merritt, granted Feb. 5, 2002 and further adapted to take advantage of certain characteristics of such invention. 
         FIG. 6  is an isometric view of an improved, integrated combination of an integrated, contoured condensate collection tray or pan and a principal water reservoir or storage container which is specially suited for the presently described system. 
         FIG. 7  is a plan view of the integrated tray and reservoir, illustrating the tray. 
         FIG. 8  is a bottom view of the integrated tray and reservoir. 
         FIG. 9  is a schematic and pictorial representation, partially cut away, of a portion of a preferred plumbing arrangement associated with collection, further cooling and distribution of water according to certain aspects of the present invention. 
         FIG. 9A  is a schematic and pictorial representation, partially cut away, of a portion of an alternative plumbing arrangement associated with collection, further cooling and distribution of water according to certain aspects of the present invention. 
         FIG. 10  is a listing of typical plumbing component parts for the system of  FIG. 9A . 
         FIG. 11  is an improved version of a water cooling and recovery system according to certain aspects of the present invention. 
         FIG. 12  is a partial front pictorial view of a system according to  FIGS. 6-8 ,  9  and  11 . 
         FIG. 12A  is a partial front pictorial view of a system according to  FIGS. 6-8 ,  9 A,  10  and a modified version of  FIG. 11 . 
         FIG. 13  is a pictorial top view of the system of  FIG. 12 . 
         FIG. 14  is an isometric view of an insulator pad used in connection with the primary evaporator coils of the systems described herein. 
         FIGS. 15   a ,  15   b  and  15   c  are top, bottom and sectional views (the latter taken along line A-A) of the insulator pad of  FIG. 14 . 
         FIG. 16  is an overall pictorial view of one system according to the present invention, having a first duct arrangement. 
         FIG. 17  is an overall pictorial view of a second system according to the present invention, having a second duct arrangement. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to  FIG. 1 , major components of an air-water recovery system are positioned preferably within a fully enclosed loop air passage duct  11 . In a preferred embodiment, duct  11  is insulated from ambient atmospheric conditions. A continuous flow of air containing water vapor (humidity), or into which moisture is injected (see below), is circulated through the closed loop air passage duct  11  by air movement means  12  such as a motor driven fan in, for example, a counterclockwise direction as seen in the drawing. A sequence of refrigeration components  14 ,  15 ,  16  is positioned within the duct  11  in ascending numerical order downstream from fan  12 . These refrigeration components comprise a first air stream cooling element  14  such as a first refrigerant evaporator having an exterior surface, a second air stream cooling element  15  such as a second refrigerant evaporator having an exterior surface, and an air stream heating element  16 , which in the preferred embodiment is a condenser of the refrigeration system. The refrigeration system further comprises a compressor  20  and first, second and third metering devices  21 ,  41 , and  22 , respectively. Refrigerant is supplied from compressor  20  to the several heating, cooling and control elements noted above. The state of the refrigerant medium is controllably altered to provide the desired temperature/pressure parameters around the loop. A suction pressure regulator  23  is provided which acts in concert with metering device  22  to cause the first cooling element  14  to operate at a selected pressure corresponding to a temperature below the dew point of the air being forced across the surface of cooling element  14 . At least a portion of the water vapor within the air moving across the surface of the first cooling element  14  condenses into liquid, thereby causing the passing air to cool (drop in temperature) while the humidity rises to 100%. The condensed liquid water is collected in a pan  24  and is passed to a storage vessel  25 . The second cooling element  15  is operated at a pressure corresponding to a temperature below the dew point of the air exiting the first cooling element  14  by controlling first metering device  21 . Preferably, second cooling element  15  is operated at a temperature at or below the freezing point of water so that substantially all or a large percentage of the remaining water (vapor) in the air stream is captured at the second cooling element  15 . 
     Referring to  FIG. 3 , metering devices  21  and  41  as well as metering device  22  are illustrated as capillary tubing. Controlling this type of metering device consists of determining the correct ratio between the length of the tubing and inside diameter of the tubing. Extremely accurate pressure and temperature relationships are attainable using this dimensioning technique. Other types of metering devices can be used instead. The preferred operating temperature of second cooling element  15  is below the freezing temperature of water. In fact, temperatures down to 0° Fahrenheit (F.) are not undesirable for second cooling element  15 . It should be understood that first cooling element  14  and second cooling element  15  may be combined within a single physical structure, thereby creating a multiple temperature refrigeration evaporator element, as well as reducing the part count. A damper  18  is positioned preferably between heating element  16  and fan  12 . Damper  18 , when opened, creates an inlet port  30  and an outlet port  31  which are useful during certain tasks performed by the apparatus, such as simple atmospheric air to water conversion. 
     Referring now to  FIGS. 1 and 2 , specific examples of operating parameters and conditions according to one aspect of the invention will be described. As shown in  FIG. 2 , at state point A, when the dry bulb temperature of the air flowing in duct  11  upstream of first cooling element  14  is 80° F., with a relative humidity (RH) of 60%, 0.0132 pounds of water per pound of dry air will be present. Using this same  FIG. 2 , it can be determined that 13.90 cubic feet of air corresponds to one pound of air. By circulating three hundred cubic feet per minute (CFM) of air in air passage duct  11 , twenty-one and one half (21.5) pounds of air per minute will be moving across the surface of the first cooling element  14 . The amount of water vapor contained in this amount of air is 0.0132×21.5=0.28 pounds or nearly ⅓ pound of water per minute, which will be passing over first cooling element  14 . The dew point for this condition is 64.9° F. By adjusting the suction pressure regulator  23 , the circulating refrigerant in first cooling element  14  is set to operate, for example, at 40° F. It can then realistically be expected that a twenty-five degree drop in temperature will result and the air will be cooled to a temperature such as 55° F. when it passes over first cooling element  14 . 
     At least a portion of the 0.28 pounds per minute of water vapor in this air will condense into liquid water upon the surface of first cooling element  14 . This portion of water can be calculated by subtracting from the amount of water entering duct  11  which has been previously calculated to be 0.0132 lb./lb. of air. The amount of water available at the temperature the air was cooled to, shown at state point B where the air leaving the evaporator  14  is saturated or 99.9% RH, is 0.0092 lb./lb. This calculation indicates that only 0.004 lb./lb. is captured. Multiplying this number by 21.5 pounds of air per minute means that out of 0.28 pounds per minute that is available, only 0.086 pounds per minute of water is being captured. Continuing, from state point B where the dew point is 55° F., this saturated air is forced across the surface of second cooling means  15  which is controlled to operate at 0° F. (below the freezing point of water). As the moisture laden air makes contact, the moisture freezes upon the surface of the second cooling means  15  and the air is cooled to 20° F. This is represented as state point C on the psychrometric chart of  FIG. 2 , where it can also be seen that the amount of water is only 0.0021 pounds per pound of air at this point. A new calculation similar to the previous calculation reveals the amount of water captured is 0.0111 lb./lb., nearly all of what was available in the air upstream of the first cooling element  14 . As the second cooling element  15  begins to accumulate ice, thereby restricting the flow of air through the enclosed circuit  11 , the temperature of suction line  23  decreases. This temperature decrease is sensed by a temperature sensing switch  40  which closes, energizing a valve  19  which then opens and allows liquid refrigerant to pass through the second (a parallel connected) metering device  41 . This connection has the immediate effect of an increase in pressure within the second cooling element  15 . Therefore an immediate increase in temperature occurs and the ice on second cooling element  15  begins to melt. This method of defrosting is superior to a hot gas defrost method common in the art of refrigeration since it uses less moving parts and assures the surfaces of the cooling elements are always maintained below the dew point of 55° F. of the entering saturated air as well. As the ice melts, the temperature of second cooling element  15  begins to approach the temperature of the first cooling element  14 . At this point, a temperature sensing switch device  40 , sensing the increase in temperature, opens; de-energizing valve  19 . Once again refrigerant is allowed to flow only through metering device  21 , reducing the temperature of the second cooling element  15  substantially. The resultant water from the melted ice is collected in drain pan  24  and directed to storage vessel  25 . The cooled air continues flowing through the duct  11  and is now directed across the surface of heating element  16  where the temperature of the air is raised to 90° F. This air is exhausted at port  31  as damper  18  is fully opened for this particular task, thereby obstructing the heated air from returning through the duct  11  to the air movement means  12 . 
     Referring to  FIG. 1  and  FIG. 3 , an alternate technique of water distillation at low temperatures is described. In this operation, damper  18  is fully closed, thereby creating a completely closed air circuit  11 . As fan  12  forces air to move throughout the closed air passage duct  11 , water in the form of a fine mist or fog is introduced into the air stream through a water introduction means  13  (for example, a spray nozzle or the like). This water need not be of a potable nature and can be brackish or salt water. A replaceable particulate filter  13   a  assures no foreign matter enters the introduction means  13 . As this water is introduced into the circulating air in the form of a fine mist, there is an immediate effect known as adiabatic cooling. The term adiabatic refers to a change of state without loss or gain of heat energy. In this case, the adiabatic process refers to evaporative cooling. Evaporative cooling can occur when air passes over the surface of water. Even at temperatures well below the boiling point, water molecules at a surface will absorb sufficient energy from passing air to change phase into gas and become water vapor. As the water vapor is absorbed into the air, energy is transformed from sensible heat into latent heat of vaporization. Accordingly, the temperature of the air falls, and its absolute humidity rises, while the overall energy content remains the same. Thus, as the water spray makes contact with the air stream, adiabatic cooling takes place. The temperature of the air stream drops and the absolute humidity rises. A water entrainment means  17  positioned between the water introduction means  13  and the first cooling means  14  assures no droplets of water are allowed to pass beyond this point. If the temperature of the air stream was 90° F. before contact with the water, it is not uncommon for a twenty degree reduction in temperature to occur. Therefore, the new condition of the air stream is 70° F. and nearly completely saturated. This means that the dew point for this condition is near 70°. As in the previous example, the same phenomena occur. That is, the vapor laden air is driven by the fan  12  and passed across at least one surface of a first cooling element  14  which is maintained at a temperature below the dew point. The first cooling element  14  causes a portion of the vapor in the air to convert into liquid water. As the air passes the first cooling element  14 , it is cooled to reach one hundred percent relative humidity. This is the customary condition for air after having passed over a refrigerant evaporator. At this point the air contains all of the moisture not captured by the first cooling element  14 . The air stream is then passed across the surface of a second cooling element  15 . The second cooling element  15  is operated at a temperature below the freezing point of water so that substantially all of the remaining water within the air stream is captured at the second cooling element  15 . As the air stream passes beyond the second cooling element  15 , it is again at one hundred percent relative humidity, though at a much cooler temperature. The air stream is then passed across a heating element  16  where the temperature of the air is drastically increased, simultaneously resulting in a significant drop in relative humidity. The air then returns through the insulated, enclosed ducted air passageway  11  to the fan  12  which forces the air through the cycle again, including the water injection or introduction step. This arrangement of adiabatic cooling, first and second cooling means, and air reheat, results in the capture of the greatest quantity of water possible in comparison to conventional techniques used for such tasks. Further, the task is accomplished with a significant decrease in energy usage, thereby resulting in higher efficiencies, with the result being a significant amount of captured water. By increasing the temperature from 20° F. leaving the second cooling element  15  to 90° F. by heating element  16 , gives a new condition of 7.5% RH; extremely dry air with a great affinity for water. Since damper  18  is fully closed the air continues to circulate and again the method of moistening air, adiabatically cooling it, subjecting the adiabatically cooled air stream to multiple temperature evaporators thereby significantly drying it, then raising the temperature of the air stream creating an air stream of extremely low relative humidity, is performed in a continuously repeated cycle until the desired amount of water is collected. The water is stored in vessel  25  and subjected to filtering and disinfecting. In extremely hot and dry climates the damper may be adjusted to open to a certain degree during this operation thereby moderating the conditions within the refrigeration components. 
     Referring to  FIG. 4 , an alternate embodiment of the invention is shown in which means to pre-cool or de-superheat refrigerant supplied from a compressor  20  is illustrated. In general, the apparatus shown in  FIG. 4  is substantially the same as that shown in  FIG. 1  with the exception that air supplied by a further fan  20   b  disposed outside the enclosed air passage loop  11  is supplied across a condenser segment  20   a  to provide an air-cooled de-superheater which provides a somewhat similar effect on the circulating refrigerant as the water-cooled de-superheater shown in U.S. Pat. No. 3,643,479 mentioned above. 
     Specifically, in  FIG. 4 , vapor compressor  20  is in fluid communication with air cooled de-superheater  20   a . Refrigerant is caused to flow out of compressor  20  into de-superheater  20   a  where air supplied by a second air movement device (e.g. a fan)  20   b , which is disposed outside of closed air loop  11 , removes the superheat from the refrigerant. It has been found to be advantageous to use a controllable speed fan  20   b  in order to be able to further control the temperature of condenser  16  and thereby more accurately control temperature of the air within air duct  11 . On-off time control of fan  20   b  similarly may be used to control air temperature within duct  11 . De-superheated refrigerant then flows into condenser  16  where the remainder of the heat content is removed by the air flow within closed loop  11  passing over condenser  16 . This causes the refrigerant to condense completely into liquid form. The liquid refrigerant passes through metering devices  41 ,  21 ,  22 , as explained previously, into controlled temperature/pressure regions of evaporators  15  and  14 , respectively, in order to collect and remove water supplied by water insertion means  13  from the circulating air within closed loop  11 , again as explained above. 
     It can therefore be seen that  FIG. 4  is similar to  FIG. 1  in many respects and the same reference characters have been used in both figures to identify the same or similar parts. 
     Referring to  FIG. 5 , rather than the air cooled de-superheater arrangement  20   a ,  20   b  of  FIG. 4 , a similar function is provided by a water cooled de-superheater  20   a ′ of the type shown in U.S. Pat. No. 6,343,479 mentioned above. The flow of cooling water for the de-superheater and its recovery is described in the &#39;479 patent and is incorporated herein by reference. In the  FIG. 5  arrangement, only a single evaporator element  14  is shown. However, it should be recognized that, as was mentioned previously, evaporator element  14  may, in fact, be a combination of evaporator elements  14  and  15 , along with the associated control devices described in connection with  FIG. 1 . Furthermore, the coolant water circulated in de-superheater  20   a ′ may be coupled to the water introduction means  13  to provide the desired water vapor in closed loop  11 . In addition, all of the air-cooled de-superheater elements included in  FIG. 4  may be coupled into the system shown in  FIG. 5 , with the elements  20   a  and  20   a ′ being connected in series in the refrigerant path from compressor  20 . In this way, the appropriate one of the de-superheaters may be operated while the other is not, according to the desired conditions of operation. 
     Referring to  FIGS. 6-8 , a principal water storage reservoir or container  25  is shown which is molded as a unitary structure from a plastic material such as a transparent polycarbonate plastic. The reservoir  25  is formed so as to facilitate collection of water and maintenance of the collected water in a potable condition, as well as to facilitate maintenance of the reservoir  25  itself and its assembly and disassembly with respect to associated water handling components. Principal water storage reservoir  25  includes, on its uppermost surface, an integral condensate collection pan or tray  24  which is dimensioned to fit below and in close proximity to evaporator coils (such as cooling elements  14 , or their equivalent) in a water collection system as will be illustrated in greater detail below. Collection tray  24  has an upstanding lip  26  surrounding an open collection volume, a downward sloping floor  27  which slopes in each direction from lip  26  to a central water collection opening  28 . This arrangement allows condensed water collected in tray  24  to drop into the generally rectangular box-shaped storage volume enclosed by the lower two thirds of reservoir  25  (typically of the order of 6-8 gallons). The tray  24  and collection opening  28  are dimensioned to accommodate an anticipated maximum rate of collection of condensate. Appropriate openings  32 ,  33 ,  34  suitable for connection, for example, of water outlet, recirculated water inlet or, as will appear below, ozone gas inlet, and level sensor fittings (see below) are provided along a substantially horizontal partial ledge or shelf  29  integrally formed adjacent to and at a lower level with respect to collection tray  24 . Shelf  29  extends along the length of reservoir  25  between its front  36  and rear walls as seen in  FIG. 6 . Water collection opening  28  may be left open by maintaining the overall air passage free of any particulate matter by means of conventional air filtering at the air inlet of the overall system. 
     A closable access opening  35  is provided in the front wall  36  of reservoir  25  to allow cleaning of the interior of reservoir  25 , if necessary, as well as to provide access for installing necessary apparatus such as level sensing floats, or plumbing or the like (see below) within reservoir  25 . The location and dimensions of access opening  35  are selected with respect to the dimensions of reservoir  25  and the apparatus to be installed within reservoir  25  to permit assembly and disassembly thereof. A water tight screw cap closure  74  (see  FIG. 16  or  17 ) is associated with access opening  35 . The polycarbonate plastic material is selected for strength, ease of fabrication and cleaning and its compatibility with maintaining the potability of the stored water. 
     Referring to  FIG. 9 , a portion of a plumbing configuration associated with sanitizing, handling and dispensing the collected water is shown. A portion of water storage reservoir  25  has been cut away to permit a better understanding of the arrangement of parts. In addition to the principal water storage reservoir  25 , in  FIG. 9 , respective first (hot) and second (cold) auxiliary water storage and delivery reservoirs  37  and  38  are provided in the system. The water collected in principal water storage reservoir  25  is supplied via a water pickup tube  78  secured within reservoir  25  in collected water outlet orifice  32  to tubing  61  and  58  in sequence, and then to an inlet side of a water pump  43 . An outlet side  60  of pump  43  is coupled by means of a vertically disposed, free-standing anti-vibration loop  85  of conduit to a fitting  86 . This loop is provided so that when the pump  43  is activated, any shock wave caused by the sudden flow of water will not be audible and will not be transferred to the structure but will be absorbed by the loop  85 . The water provided by pump  43  is coupled to a particulate filter such as an activated carbon filter by means of appropriate food grade tubing and fitting arrangements. The filter preferably comprises an easily replaceable commercially available cartridge which, for example, can be screwed into a conveniently mounted filter base  42 ′ near the top of the apparatus. 
     After passing through the filter assembly  42 ′, the collected water passes through a divider (“T”) or valve  66  to respective first water delivery reservoir  37  and second water delivery reservoir  38 , as may be desired. Appropriate first and second dispensing nozzles or faucets  44  and  45  are provided in a convenient location for a user to draw water from a respective one of the delivery reservoirs  37 ,  38 . Reservoir  38  (as will be described below) is provided with additional cooling means so as to provide relatively cold water for drinking while reservoir  37  may be arranged to provide water at a different temperature, e.g., hot water, by appropriate added elements (such as a heater), if desired. 
     In order to insure the safety of the recovered water for human consumption, a particularly advantageous arrangement of water treatment apparatus forming an ozone purification system is provided in the configuration shown in  FIG. 9 . To that end, a corona discharge type of ozone generator  75 , such as a commercially available ozone generator Model FM 300S manufactured by Beyok Company is employed. Ozone generator  75  is located in the apparatus at a point where ambient air is available. As can be seen in  FIGS. 9 and 12 , appropriate tubing  76 , such as stainless steel tubing, is coupled from ozone generator  75  to a fitting  77  fastened into reservoir access opening  33 . First and second spaced apart, porous, ozone diffusing stones  81  and  82  are supported within reservoir  25  at the respective ends of hollow tubular support arms  83 . The tubular support arms  83  each are connected to a downwardly extending supply tube  84  which is fastened to fitting  77  and the combination of elements  77 ,  83 ,  84  supplies ozone to each of the diffusing stones  81 ,  82 . Water pick up tube  78  has a lower open end disposed adjacent to one of the diffusing stones  81  in order to pick up ozoneated water. Whenever electrical power is applied to pump  43  to pump collected water out of reservoir  25  to the first and/or second auxiliary reservoirs  37 ,  38 , ozone generator  75  is also energized and ozone is produced from ambient air by ozone generator  75 . That is, ordinary oxygen molecules (O 2 ) are converted to ozone (O 3 ) by ozone generator  75 . The ozone passes through tubing  76 , fitting  77 , supply tube  84  and tubular (hollow) support arms  83  to each of the diffusing stones  81 ,  82 . In this way, ozone is drawn into the pickup line  76  to sanitize the plumbing lines and insure that safe water is dispensed. Ozone generator  75  may also be activated periodically (e.g. at fifteen minute intervals) when the system is not being called upon to dispense water (e.g. overnight). In this way, the purity of the water at all times is ensured. Bubbles of ozone appear in the water in reservoir  25  in the vicinity of each of stones  81 ,  82  and two rising columns of such bubbles continue to form in the collected water as ozone is supplied. The diffusing stones  81 ,  82  are spaced apart a sufficient distance to facilitate dispersion of the injected purification ozone substantially throughout the water in reservoir  25 . By placing the pickup tube  78  adjacent one of the stones, it is insured that water pumped out of reservoir  25  is sterilized by newly generated ozone. It should also be noted that cycling of the apparatus in the manner described above, as well as controlling such parameters as fan speed and/or duty cycle to improve condensate collection under conditions of different temperature and/or humidity, readily may be accomplished by means of available programmable microcontrollers and appropriate temperature, time and humidity sensors well known to those skilled in the art. In that regard, reference to the such parameters and their relationships as shown in  FIG. 2  above are helpful. 
     The ozone generator  75  may also be suitably turned on or off according to other parameters in the system. For example, a water level sensing assembly comprising a high water level float switch  48  and a low water level float switch  49  mounted in opening  34  of reservoir  25  and extending downwardly into the reservoir  25  is provided to sense two extremes of water level in reservoir  25 . Low water level float switch  49  may be connected, for example, in the power circuit for ozone generator  75  to turn ozone generator  75  on only if the water level in reservoir  25  is sufficiently high that the ozone will be emitted and absorbed in the water. Correspondingly, high water level float switch  48  may be connected in the power circuit for refrigerant compressor  20 , pump  43  (and other devices) so that production of water ceases when the water level in reservoir  25  is at an upper acceptable limit, thereby preventing overflowing and waste of resources. 
     In an alternative water handling arrangement shown in  FIG. 9A , where similar parts are numbered the same as in  FIG. 9 , a shut-off valve  64  is provided between water outlet line  61  and the input to a UV lamp  39  which serves, instead of ozone generator  75 , to destroy bacteria in the circulating water. Water passes from UV lamp assembly  39  through particulate filter  42  and through pump  43  in this arrangement. A flow divider  66  is provided between the output of pump  43  and the first and second water delivery reservoirs  37 ,  38 . A control solenoid  46  is provided as shown to regulate water flow from second delivery reservoir  38  to principal water reservoir  25  or to cold water faucet  45 , depending on water level conditions and demands in the system. 
     Referring to  FIGS. 11 ,  12  and  12 A, a modified version of cold water reservoir  38  is shown. In  FIG. 11 , arrows indicate the direction of refrigerant flow from compressor  20 , through a condenser coil  16 , then through an evaporator (air cooling) coil  14  and returning to condenser  20 . In accordance with one aspect of the present invention, a secondary parallel refrigerant branch line, in the form of a capillary tube or metering device  50 , is arranged to divert a fraction of the liquid refrigerant available at the output of condenser  16  (i.e. before the entrance into evaporator  14 ) to a secondary evaporator coil  15 ′ which is coupled in parallel with evaporator  14 . In a preferred arrangement, secondary evaporator coil  15 ′ is wrapped closely around cold water reservoir  38  so as to cool the accumulated water in reservoir  38  to a temperature lower than room temperature (e.g., in the range of 10° C.-20° C. or suitable for human consumption). A further purpose of secondary evaporator coil  15 ′ is to provide an auxiliary flow of cooler return gas to compressor  20 , thereby allowing compressor  20  to operate at a lower temperature than would be the case without evaporator coil  15 ′. To this end, liquid refrigerant supplied by metering device  50  enters coil  15 ′ at its lower end  67  (as shown in  FIGS. 11 ,  12  and  12 A) and is converted to vapor as it traverses coil  15 ′, cooling the water in cold water reservoir  38 . At the upper end  68  of coil  15 ′, the relatively cool vapor from coil  15 ′ is combined with the higher energy vapor in refrigerant suction line  79  from primary evaporator  14 . The combined vapor is returned to the suction side  80  of compressor  20 , thereby allowing compressor  20  to operate at a lower temperature. In this manner, a single compressor  20  may be used both for capturing water by condensation from the passing air stream and to cool at least a portion of the collected water to a still lower temperature (e.g., in the range of 10° C.-20° C. suitable for human consumption). 
     It should be noted (see  FIG. 12A ) that capillary tube  50  (a relatively long, small diameter tube) is connected in the refrigerant system from one end of the evaporator coil  14  in the upper portion of the apparatus to the lower end  67  of secondary evaporator coil  15 ′. In the arrangement shown in  FIG. 12 , the capillary tube  50  preferably is fastened in intimate thermal transfer relationship with the surface of the tubing that comprises secondary evaporator coil  15 ′ so that the low temperature of coil  15 ′ pre-cools or subcools the refrigerant in capillary tube  50 . It has also been found to be advantageous to place the individual turns of evaporator coil  15 ′ in close thermal contact with each other by, for example, soldering the turns to each other (see  FIGS. 12 and 12A ). In this way, heat is transferred to the boiling refrigerant in the individual turns of coil  15 ′ one turn to the next which provides a more even boiling of the refrigerant throughout the length of the coil  15 ′. 
     Referring to  FIG. 13  which is a top view of a typical configuration of the apparatus shown in  FIG. 12 , as is customary in refrigeration systems, evaporator coil  14  comprises a serpentine array of tubing having substantially parallel, straight sections  69  joined together by generally u-shaped ends and/or hairpins  70 . Fins  71  are provided along the straight sections  69  of tubing to increase the effective surface area of the evaporator tubing  14 . However, although the hairpins/ends  70  are cold surface areas, amounting to as much area as seven or eight straight sections  69  of the operative tubing, they are disposed outside the air flow and do not contribute to recovery of water from the air. It has been found that by insulating the hairpins/ends  70 , the remainder of the evaporator coil  14  can provide increased cooling and increased water collection from the air as compared to a system in which the hairpins/ends are not insulated. To that end, blocks of insulating material  72  (e.g. appropriate molded plastic such as styrofoam or other insulating material) as shown in  FIGS. 14 and 15   a - 15   c , are provided with appropriate molded slots  73  configured according to the locations of the hairpins/ends  70  in the evaporator coil  14 . The insulating blocks  72  are self-supporting and are placed over the hairpins/ends  70  where such ends extend from the generally rectangular shape of coil  14 . The insulating blocks  72  are not shown mounted in the drawings but, as shown in the drawings, they have a flat outer surface  73  and cover the coil ends  70  in the apparatus to insulate them from ambient air. 
     Referring to  FIG. 16 , a partially assembled system embodying various aspects of one or more novel features is shown. In particular, one geometric arrangement of an air duct  11  is shown having a generally rectangular cross section in a lower (inlet) area and a generally cylindrical cross section in an upper (outlet) area. 
     Referring to  FIG. 17 , a second version of a partially assembled system embodying various aspects of the invention is shown. In general,  FIGS. 16 and 17  are similar but, in  FIG. 17 , air duct  11 ′ has a smaller, generally rectangular cross section in its lower portion and a larger rectangular cross section in its upper area. In addition, typical programmable microcontrollers  86  for controlling the sequence of operations as explained above are shown in each of  FIGS. 16 and 17 . Other suitable configurations will be apparent to persons skilled in this art. 
     The principal tasks of air to water conversion, as well as low temperature water distillation and desalination are well within the capabilities of the above described inventive combinations. 
     Accordingly, while one or more preferred embodiments of the present invention are illustrated and described herein making use of a variety of features and combinations thereof, it should be understood the invention may be embodied otherwise than as herein specifically illustrated or described and that within the embodiments certain changes in the details of construction, as well as the arrangement of parts, may be made without departing from the principles of the present invention.