Abstract:
A method and apparatus for producing potable water from non-potable water, in which a supply of air is passed through a heating unit to increase the air temperature and then passed through an evaporative cooling media through which the non-potable water is passed in liquid/gas contact with the heated air. The temperature of the air leaving the evaporative media is reduced as a result of contact with the water, and its moisture content is increased. The cooler moist air is then passed through a cooling coil to cause the moisture in the air to condense as liquid water, which is then collected and made suitable for use as drinking water.

Description:
FIELD OF THE INVENTION  
       [0001]     The present invention relates to a method and apparatus for producing potable water from non-potable water while treating air to provide conditioned air to an enclosure. Non-potable water is defined as water from a source that is not drinkable, such as, but not limited to, an ocean or sea (salty or brackish), a lake, a natural or man-made reservoir, a stream or river, etc.  
       BACKGROUND OF THE INVENTION  
       [0002]     A variety of different technologies have been developed over the years to produce drinking water from non-potable water. These technologies often involve the consumption of substantial amounts of power and are relatively expensive. In addition, demand for this technology is often located in very hot and humid areas of the world, and particularly in isolated locations which also require air treatment for the purpose of providing conditioned air to living spaces. That need creates additional power consumption requirements, which increases the total cost of any such installation.  
       OBJECTS OF THE INVENTION  
       [0003]     It is an object of the present invention to provide a new and improved method and apparatus for producing potable water from non-potable water, while at the same time producing conditioned air for supply to enclosures.  
         [0004]     Yet another object of the present invention is to provide an improved method and apparatus for producing potable water from non-potable water, which overcomes the disadvantages of prior art desalinization arrangements.  
         [0005]     A still further object of the present invention is to provide a combined non-potable water purification system and air conditioning system with reduced power requirements.  
       SUMMARY OF THE INVENTION  
       [0006]     In accordance with an aspect of the present invention, a method and apparatus for producing potable water from non-potable water and for also producing conditioned air is provided in which a supply of ambient atmospheric air, or other air, is passed through a heating device in order to increase its temperature to improve the rate of evaporation of water exposed to that air. The heated air is passed through an evaporative cooling media to which non-potable water is supplied for flow in liquid gas contact with the heated air. As the heated air passes through the evaporative media in contact with the non-potable water, the water evaporates entering the air and the air temperature is reduced while its moisture content is increased. The thus cooled and moistened air then flows through a cooling unit which causes the water moisture in the air to condense as liquid water. That water is collected, treated and optionally irradiated by UV light and or ozonator in order to render it drinkable.  
         [0007]     In accordance with another aspect of the present invention, the heating and cooling devices used in the process consist of the heating and cooling coils of a refrigerant based air conditioning unit.  
         [0008]     In accordance with a still further aspect of the invention, a desiccant wheel is positioned downstream of the cooling coil to further dry the cooled air leaving the coil. This dried and cooled air can then be supplied to an enclosure for air conditioning purposes.  
         [0009]     In an alternative arrangement, a further cooling coil can be positioned downstream of the first coil, in lieu of the desiccant wheel, to provide further cooling and drying of the air for air conditioning purposes.  
         [0010]     In yet another alternative arrangement, the condenser coil may be positioned downstream of the first coil, in lieu of the desiccant wheel, to provide even greater performance of the system in a water making only mode. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0011]     The above, and other objects, features and advantages of this invention will be apparent in the following detailed description of illustrative embodiments thereof, which is to be read in connection with the accompanying drawings, wherein:  
         [0012]      FIG. 1  is a schematic diagram of the water purification and air conditioning system of the present invention;  
         [0013]      FIG. 2  is an illustration similar to  FIG. 1  of another embodiment of the invention;  
         [0014]      FIG. 3  is a schematic illustration of a third embodiment of the invention suitable for use in remote ocean locations, such as oil well platforms; and  
         [0015]      FIG. 4  is a psychometric diagram of the process performed by the apparatus shown in  FIG. 3 . 
     
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS  
       [0016]     Referring now to the drawings in detail, and initially to  FIG. 1  thereof, a non-potable water treatment and air conditioning plant  10 , constructed in accordance with the present invention, is illustrated. The system of  FIG. 1  includes a refrigeration cycle unit  12 , which includes a heating coil  14 , a cooling coil  16 , a refrigerant supply line  18 , and a compressor  20 . The refrigeration unit operates in a known manner such that coil  16  absorbs heat from air passing through it to produce cooled and dried air, while heating coil  14  discharges heat from the refrigerant in line  18 , which was collected in the coil  16 , to the air passing through it.  
         [0017]     In the embodiment of the present invention, a supply of outside air is caused to flow through the refrigeration unit, as indicated schematically by the arrows A and B, under the influence of a fan or blower  17  first through the heating coil  14 , and thence through the cooling coil  16 . However, in accordance with a feature of the present invention, an evaporative cooling pad  24  of known construction is positioned between the two coils. This evaporative cooling pad is preferably formed from multiple layers of corrugated sheet material, with the corrugations preferably being cross-fluted in order to produce a plurality of passageways through the device located at angles to the vertical or horizontal directions. Such corrugated fill material is well-known in evaporative cooling arts, and is manufactured by the assignee of this application, Munters Corporation.  
         [0018]     The passageways of the corrugated panels are opened towards the faces  26 ,  28  of the evaporative media to receive the air flow from the heating coil  14  and discharge it to the cooling coil  16 .  
         [0019]     A water supply system  30  is also provided for supplying water to the top surface  32  of the evaporative pad. The water supply system includes a pump  34 , which through piping  36  can draw non-potable water to a water distribution pan or spray head  38  immediately above the evaporative pad in a conventional manner such as is used with evaporative coolers. The non-potable water preferably is sprayed across the top of the evaporative pad and then flows through the passageways of the pad toward the bottom of the pad.  
         [0020]     The air which flows through the heating coil  14  is heated during its passage through the coil, removing heat from the refrigerant. Heating of the air increases its ability to cause evaporation of moisture when in contact with water.  
         [0021]     As this heated air passes through the passageways of the evaporative media, the water flowing on the surfaces of the corrugated sheets in the pad evaporates, thereby reducing the temperature of the air leaving the pad while increasing its moisture content.  
         [0022]     A large amount of water is supplied to the evaporator pad to keep the pad clean and free from buildup of salts and minerals. A collection gutter  40  is provided at the bottom of the pad to collect the remaining water and return it to the non-potable water source.  
         [0023]     As the air flowing from the evaporative cooling pad to the cooling coil  16  passes through the coil, the cold coil causes the moisture in the air to condense on the coil and drip to the bottom of the coil, where it is collected in a water collection trough  42  which supplies the collected water through a pipe  44  to a storage tank  46 . The air leaving the coil  16  is now drier than the air that entered the coil and cooler than the air when it left the evaporative pad. That air is now available for use as conditioned air, e.g. as supply return or make up air, for a building or other enclosure.  
         [0024]     The water collected in storage tank  46  is pure water, with the salt or other dissolved solids removed. This water would be potable but, as a precaution the water may be further treated in order to assure its safety for drinking. Thus, if desired, a conventional ozonator  48  can be mounted in the storage tank for adding oxygen and ozone to the water. The water is collected through a pump  50  under the influence of a pressure tank  52  in a known manner, and supplied to a pair of filters  54  (preferably a 5 micron filter) and  56  (preferably a 1 micron filter) and thence to a conventional T &amp; O filter  58 . Finally, the water can be exposed, through transparent piping, to ultraviolet light from a surrounding set of ultraviolet light bulbs  60  to kill any bacteria remaining in the water.  
         [0025]     As a result, a simple system is provided for not only demineralizing water, but cooling make up air for use in air conditioning systems. Although the invention contemplates producing potable water for human consumption, the use of the potable water produced by the invention is not limited to drinking but may be used for other purposes as well, e.g. as a process liquid.  
         [0026]     In the embodiment of  FIG. 1 , an additional air drying unit may also be provided to further improve the condition of air being supplied to the enclosures and the cooling coil. In particular, a conventional desiccant wheel  70  of known construction may be provided downstream of cooling coil  16 . This wheel is formed of corrugated material which creates a series of passages through the wheel from one face  72  to the other  74 . The wheel surfaces defining the passageways are coated with a desiccant material so that as the air from coil  16  passes through the wheel the desiccant materials absorb moisture in the air, thus further drying the air before it is supplied to the enclosure.  
         [0027]     As is known in conventional desiccant wheel devices, wheel  70  rotates about its central axis  76  to continuously bring the surfaces of the wheel past a regeneration zone  78 , which is defined in the wheel by duct work (not shown) on opposite sides of the wheel. In the regeneration zone, heated air supplied from a heating device  80  of known construction (which may, for example, be a heating coil containing waste heat through which air is circulated by a fan  82 ). The heated air passes from the heating device  80  through the duct work through the regeneration zone  78  and removes the moisture from the desiccant material.  
         [0028]      FIG. 2  illustrates another embodiment of the present invention, wherein like numerals represent like parts. In this embodiment, in lieu of the desiccant wheel  70 , a second cooling coil  80  is provided downstream of cooling coil  16 . This cooling coil can be connected either in the same refrigerant circuit as coil  16 , or in a separate refrigerant circuit. The use of the second cooling coil  80  provides additional cooling and drying to the air stream as necessary. The water collected on the second cooling coil can also be supplied to the tank  46  if desired, or it can simply be discharged.  
         [0029]      FIG. 3  illustrates a third embodiment of the invention, particularly useful on ocean platforms, such as oil drilling rigs or any other application where a non-potable water source and waste heat are available. In this embodiment, as an example, an oil platform  100  is schematically illustrated on which the water treatment and air conditioning unit  110  is mounted. The system  110  includes a heating coil  114 , a cooling coil  116 , and an evaporative pad  128  positioned between the two coils. The coil  114  is connected by a piping system  111  to a source of waste heat  113 . This source of waste heat can be any known source available, for example, on an oil drilling platform, such as, for example, exhaust from electrical generating units which can be used to heat water flowing in the coils  114 .  
         [0030]     The cooling coil  116  is arranged to receive and discharge sea water or other non-potable water in a circuit with the ocean or other non-potable water source. In the ocean example, a submerged pump  130  is provided, which draws water from the ocean at depths where the ocean temperature is at most 75° F., and supplies the cool water through a vertical pipeline  132  to the coil  116 . The cooling water passes through the coil and is discharged through another pipeline  34  returning it to the ocean. As an alternative to a deep water submersible pump, a centrifugal pump at the ocean surface may be used.  
         [0031]     Atmospheric air is drawn through the system by the fan  115 . The air first enters the heating coil  114 , is warmed by the waste heat, and is supplied then to the evaporative pad  128 . As previously described, the pad is supplied with non-potable water on its upper surface in a spray or drip pattern in a known manner through a discharge head  138  from a supply line  139  which also receives the water from the supply line  132 . The heated air leaving the heating coil enters the evaporative pad and is cooled by evaporation of the water in the pad and absorbs moisture and humidity until it exits the pad. The now cooled and moist air enters the cooling coil where it is cooled and dried as the moisture in the air condenses on the coil  116  and is collected in the receptacle  42  for use as potable water, as described above.  
         [0032]     In the illustrative embodiment of  FIG. 3 , as shown in the psychometric diagram of  FIG. 4 , the air entering the heating coil  114  at point A has a temperature of 75° F. and a 74° F. wet bulb temperature. After passing through heating coil  114 , the air temperature rises to 160° F. at point B, but its humidity content remains the same. After passing through the evaporative pad, the temperature of the air is decreased to 94° F., but its moisture content increases to point C. This cooled and moist air is then further cooled in the cooling coil  116  to a temperature of 85° F. or less, and a lower moisture content.  
         [0033]     Under these conditions, and using a pumping system in which 3 gallons per minute of non-potable water are applied to the evaporative pad, approximately 25 gallons per hour of fresh water can be recovered. In addition, cooled, dried air is available for air conditioning the enclosures of the oil platform.  
         [0034]     Accordingly, a very simple and economical unit is provided which can perform two important functions in remote hot locations, i.e., the creation of potable water and the production of air conditioned air suitable for supply to enclosures.  
         [0035]     Although illustrative embodiments of the invention have been described herein with reference to the accompanying drawings, it is to be understood that various changes and modifications may be effected therein by those skilled in the art, without departing from the scope or spirit of this invention.