Abstract:
Planar element adapted to form, when stacked with a plurality of other such elements, a heat exchanger, comprising an inlet region, a first zone adapted to direct flow from the inlet region towards a second zone, a second zone comprising at least one cutout in the plane of the planar element, adapted to accommodate a cooling core, a third zone, adapted to direct flow from the second zone towards an outlet region and an outlet region, the planar element comprising a first blockage protrusion disposed along a first group of said side edges, the first group comprising at least a side edge adjacent to said outlet region, and a second blockage protrusion disposed along a second group of said side edges, the second group comprising at least a side edge adjacent to said inlet region.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a Continuation application of U.S. patent application Ser. No. 13/834,857, filed on Mar. 15, 2013, published as US Patent Application Publication No. US 2014-0261764 published on Sep. 18, 2014 and entitled DEHUMIDIFICATION APPARATUS which is incorporated in its entirety herein by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates to dehumidification generally. 
       BACKGROUND OF THE INVENTION 
       [0003]    Various types of dehumidifiers are known in the art. 
       SUMMARY OF THE INVENTION 
       [0004]    The present invention seeks to provide improved heat exchanger planar elements. 
         [0005]    There is thus provided in accordance with a preferred embodiment of the present invention planar element adapted to form, when stacked with a plurality of other such elements, a heat exchanger, the planar element comprising an inlet region, a first zone adapted to direct flow from the inlet region towards a second zone, a second zone comprising at least one cutout in the plane of the planar element, adapted to accommodate a cooling core, a third zone, adapted to direct flow from the second zone towards an outlet region and an outlet region. Preferably the perimeter of the planar element comprises side edges. 
         [0006]    According to embodiments of the present invention the planar element may comprise a first blockage protrusion disposed along a first group of said side edges, the first group comprising at least a side edge adjacent to said outlet region, the first blockage protrusion is adapted to block flow from said inlet region directly to said outlet region and a second blockage protrusion disposed along a second group of said side edges, the second group comprising at least a side edge adjacent to said inlet region, the second blockage protrusion is adapted to block flow from said outlet region directly to said inlet region. 
         [0007]    According to further embodiments the planar element comprise at least one first guiding protrusion adapted to guide the airflow within said first region from the inlet region. The planar element may further comprise at least one second guiding protrusion adapted to guide the airflow within said third region toward the outlet region. 
         [0008]    According to yet further embodiments the planer element may comprise at least one third protrusion is disposed in said first region and adapted to keep a defined gap between said planar element and a second planar element disposed adjacent to the planar element, in the inlet region. 
         [0009]    According to further embodiments the planar element may further comprise at least one fourth protrusion is disposed in said third region and adapted to keep a defined gap between said planar element and a second planar element disposed adjacent to said planar element, in the outlet region and at least one fifth protrusion disposed around said cutout adapted to keep a defined gap between said planar element and a second planar element disposed adjacent to the planar element, in the cutout region. 
         [0010]    According to further embodiments the planar element may further comprise at least a first set of relatively parallel protrusions adapted to guide the airflow within said first region and at least a second set of relatively parallel protrusions adapted to guide the airflow within said third region. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]    The present invention will be understood and appreciated more fully from the drawings in which: 
           [0012]      FIGS. 1A and 1B  are simplified top view and bottom view pictorial illustrations of a dehumidification apparatus constructed and operative in accordance with a preferred embodiment of the present invention; 
           [0013]      FIG. 1C  is a simplified exploded view illustration of the dehumidification apparatus of  FIGS. 1A &amp; 1B ; 
           [0014]      FIGS. 2A and 2B  are simplified top view and bottom view illustrations of a base element, forming an optional part of the dehumidification apparatus of  FIGS. 1A-1C ; 
           [0015]      FIGS. 3A and 3B  are exploded view illustrations of a heat exchange assembly including a cooling core and a core-surrounding air flow pre-cooling and post heating assembly (CSAFPCPHA) constructed and operative in accordance with first and second preferred embodiments of the invention and forming part of the dehumidification apparatus of  FIGS. 1A-1C ; 
           [0016]      FIGS. 4A and 4B  are simplified illustrations of a first end plate element, forming part of the dehumidification apparatus of  FIGS. 1A-1C ; 
           [0017]      FIGS. 5A and 5B  are simplified illustrations of a second end plate element, forming part of the dehumidification apparatus of  FIGS. 1A-1C ; 
           [0018]      FIGS. 6A and 6B  are respective simplified assembled view and exploded view illustrations of a cooling core assembly forming part of the heat exchange assembly of  FIG. 3A ; 
           [0019]      FIGS. 7A and 7B  are respective simplified assembled view and exploded view illustrations of a cooling core assembly forming part of the heat exchange assembly of  FIG. 3B ; 
           [0020]      FIGS. 8A and 8B  are respective simplified assembled view and exploded view illustrations of a core-surrounding air flow pre-cooling and post heating assembly (CSAFPCPHA) forming part of the heat exchange assembly of  FIGS. 3A &amp; 3B ; 
           [0021]      FIGS. 9A and 9B  are respective simplified plan view and pictorial view illustrations of a first side of a first plate of the core-surrounding air flow pre-cooling and post heating assembly (CSAFPCPHA); 
           [0022]      FIGS. 10A and 10B  are respective simplified plan view and pictorial view illustrations of a second side of a first plate of the core-surrounding air flow pre-cooling and post heating assembly (CSAFPCPHA); 
           [0023]      FIGS. 11A and 11B  are respective simplified plan view and pictorial view illustrations of a first side of a second plate of the core-surrounding air flow pre-cooling and post heating assembly (CSAFPCPHA); 
           [0024]      FIGS. 12A and 12B  are respective simplified plan view and pictorial view illustrations of a second side of a second plate of the core-surrounding air flow pre-cooling and post heating assembly (CSAFPCPHA); 
           [0025]      FIG. 13  is a simplified, partially exploded, pictorial illustration of part of the heat exchange assembly of  FIGS. 3A and 3B , showing typical air flows between adjacent embossed generally planar elements; and 
           [0026]      FIGS. 14A ,  14 B,  14 C and  14 D are simplified illustrations of air flow through the heat exchange assembly of  FIGS. 3A and 3B , where  FIG. 14A  is a planar view and  FIGS. 14B ,  14 C and  14 D are sectional views taken along respective section lines B-B, C-C and D-D in  FIG. 14A . 
       
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0027]    The present invention describes apparatus which produces dehumidification and can be embodied in a number of alternative operational contexts, such as part of a dehumidification apparatus, an air conditioner or a water generation system providing water for drinking or any other use. The apparatus described hereinabove normally requires an air flow of humid air thereto and a concomitant air pressure gradient thereacross. It also requires provision of a coolant fluid, which may be any suitable gas or liquid. 
         [0028]    Reference is now made to  FIGS. 1A-3B , which are simplified pictorial illustrations of a dehumidification apparatus  100  constructed and operative in accordance with a preferred embodiment of the present invention. As seen in  FIGS. 1A-3B , the dehumidification apparatus  100  includes a cooled core  102  coupled to an external cooling source (not shown) via a cooling fluid inlet pipe  104  and a cooling fluid outlet pipe  106 . The cooling fluid may be any suitable coolant, such as ammonia or FREON®, which are supplied in a partially liquid phase and change to a gaseous phase in the core  102 , or a chilled liquid, typically water or alcohol, which remains throughout in a liquid phase. 
         [0029]    At least first and second relatively humid air inlet pathways  108  lead to the cooled core  102  and at least first and second relatively dry air outlet pathways  112  extend from the cooled core  102 . 
         [0030]    In accordance with a preferred embodiment of the present invention, there is provided a core-surrounding air flow pre-cooling and post heating assembly (CSAFPCPHA)  120  wherein the at least first and second relatively dry air outlet pathways  112  are in heat exchange propinquity with respective ones of the at least first and second relatively humid air inlet pathways  108 , whereby relatively humid air in the first and second relatively humid air inlet pathways is precooled upstream of the cooled core  102  and relatively dry air in the first and second relatively dry air outlet pathways is heated downstream of the cooled core  102 . 
         [0031]    It is a particular feature of an embodiment of the present invention that the cooled core  102  is formed of core elements, such as core plates  122 , along which an air flow passes, and the at least first and second relatively humid air inlet pathways and the at least first and second relatively dry air outlet pathways are formed of pathway elements, such as embossed generally planar elements  124  and  126 , along which an air flow passes, the core elements having a relatively high thermal conductivity in a direction along which the air flow passes and the pathway elements having a relatively low thermal conductivity in a direction along which the air flow passes. It is appreciated that core plates  122  are aligned with and sealed with respect to corresponding planar elements  124  and  126 . 
         [0032]    As seen particularly in  FIGS. 1A-1C , the dehumidification apparatus  100  also preferably includes a base subassembly  130 , which provides a sump for drainage of condensate, end plate subassemblies  132  and  134 , end cover plates  136  and  138 , a top air flow sealing plate  140  which preferably restricts inlet air flow to be along the passageways  108 , a pair of bottom air flow sealing plates  142  which preferably restrict outlet air flow to be along the passageways  112  and a pair of side air flow sealing plates  144 , which separate between respective pairs of inlet and outlet air flow passageways  108  and  112 . A circumferential plate  148 , shown here symbolically, separates between an ambient relatively humid air environment which is maintained at a relatively high pressure and a relatively dry air environment, which is maintained at a relatively low pressure. 
         [0033]    Turning now specifically to  FIGS. 2A &amp; 2B , which are simplified illustrations of a base subassembly forming an optional part of the dehumidification apparatus of  FIGS. 1A &amp; 1B , it is seen that the base subassembly is typically welded of sheet metal and includes a pair of mutually inclined plates  160  and  162  which are joined by a pair of end portions  164  and  166  which define legs  168 . A pair of sump apertures  170  are preferably formed at opposite ends of the junction of plates  160  and  162  and are preferably fitted with respective sump pipes  174 . 
         [0034]    Turning now to  FIGS. 3A and 6A  &amp;  6 B, it is noted that these drawings illustrate a heat exchange assembly including a cooling core  102  and a core-surrounding air flow pre-cooling and post heating assembly (CSAFPCPHA)  120  particularly suited for use with a gaseous coolant, such as FREON®, and accordingly coolant piping  180  is preferably provided with a distributor  182 , which divides a flow of gas into multiple separate flows, each of which passes through a separate gas circulation pathway. 
         [0035]    Turning now to  FIGS. 3B and 7A  &amp;  7 B, it is noted that these drawings illustrate a heat exchange assembly including a cooling core  102  and a core-surrounding air flow pre-cooling and post heating assembly (CSAFPCPHA)  120  particularly suited for use with a liquid coolant, such as chilled water or alcohol, and accordingly coolant piping  190  is preferably provided without a distributor  182 . 
         [0036]    Reference is now made to  FIGS. 4A &amp; 4B , which illustrate end plate  132 . It is seen that end plate  132  comprises a generally planar portion  202  having an array of apertures  204  arranged to accommodate coolant piping, such as piping  180  or  190 , and preferably includes a plurality of bent over edges  206  and a plurality of double bent over edges  208  onto which end cover plate  136  may be sealingly attached. 
         [0037]    Reference is now made to  FIGS. 5A &amp; 5B , which illustrate end plate  134 . It is seen that end plate  134  comprises a generally planar portion  222  having an array of apertures  224  arranged to accommodate coolant piping, such as piping  180  or  190 , and preferably includes a plurality of bent over edges  226  and a plurality of double bent over edges  228  onto which end cover plate  138  may be attached. It is noted that one of bent over edges  226  is preferably formed with an aperture  230  which accommodates cooling fluid inlet pipe  104  and cooling fluid outlet pipe  106 . 
         [0038]    Reference is now made to  FIGS. 8A-12B , which illustrate the structure of the core-surrounding air flow pre-cooling and post heating assembly (CSAFPCPHA). As seen in  FIGS. 8A &amp; 8B , the CSAFPCPHA is made up of a stack of two different embossed generally planar elements  124  and  126  which are preferably arranged in mutually interdigitated touching relationship with each other about the core  102 . 
         [0039]    The structure and operation of embossed generally planar elements  124  and  126  will now be described with specific reference to  FIGS. 9A-12B . It is noted that planar elements  124  and  126  are preferably formed by conventional vacuum forming techniques from relatively non-conductive flexible material, typically plastic, such as PVC and PET, typically of thickness 0.3 mm. 
         [0040]    Turning first to generally planar element  124 , a first side thereof, designated by reference numeral  300 , is shown in  FIGS. 9A and 9B  and a second side thereof, designated by reference numeral  302 , is shown in  FIGS. 10A and 10B . Planar element  124  preferably has ten side edges, which are designated, clockwise with reference to  FIG. 9A , by reference numerals  320 ,  321 ,  322 ,  323 ,  324 ,  325 ,  326 ,  327 ,  328  and  329 . Planar element  124  is formed with a number of protrusions, which extend above the plane, designated by reference numeral  330 , of planar element  124 , in the sense of  FIG. 9A , to a height of approximately 3 mm and which will now be described in detail. Due to manufacture of planar elements  124  and  126  by vacuum forming, there are recesses which correspond with each of the protrusions. 
         [0041]    As seen in  FIGS. 9A &amp; 9B , a first side  300  of planar element  124  includes an air flow blockage protrusion  340 , which extends clockwise in the sense of  FIG. 9A , at first narrowly, from a location near the junction of edges  320  and  329 , along and slightly spaced from edge  320  where it becomes wider and then narrows, and narrowly along and spaced from edges  321  and  322 . Protrusion  340  serves to prevent air flow above plane  330  via edges  320 ,  321  and  322 . Planar element  124  also includes an air flow blockage protrusion  342 , which extends clockwise in the sense of  FIG. 9A , narrowly, from a location near the junction of edges  325  and  326  and along and slightly spaced from edges  326 ,  327  and  328 . Protrusion  342  serves to prevent air flow above plane  330  via edges  326 ,  327  and  328 . Planar element  124  also includes an air flow blockage protrusion  344 , which extends along and slightly spaced from edge  324 . Protrusion  344  serves to prevent air flow above plane  330  via edge  324 . 
         [0042]    Planar element  124  also includes, at first side  300 , an air flow guiding protrusion  346  at what is typically an inlet region  348  above plane  330  and an air flow guiding protrusion  350  at what is typically an outlet region  352  above plane  330 . 
         [0043]    Planar element  124  also includes, at first side  300 , an array  360  of mutually spaced enhanced counter flow heat exchange (ECFHE) protrusions  362  downstream of inlet region  348 . Each of mutually spaced protrusions  362  preferably has a tapered inlet end  364  and a tapered outlet end  366 . 
         [0044]    Planar element  124  also includes, at first side  300 , an array  370  of mutually spaced enhanced counter flow heat exchange (ECFHE) protrusions  372  upstream of outlet region  352 . Each of mutually spaced protrusions  372  preferably has a tapered inlet end  374  and a tapered outlet end  376 . 
         [0045]    Planar element  124  also includes, at first side  300 , a plurality of mutual inner edge spacing protrusions  380  preferably arranged at the sides of a generally rectangular cutout  382  which accommodates core  102 . 
         [0046]    Planar element  124  also includes, at first side  300 , a plurality of mutual outer edge spacing protrusions  390  preferably arranged along edges  323  and  329 . 
         [0047]    As seen in  FIGS. 10A &amp; 10B , second side  302  of planar element  124  includes a recess  440 , which extends counterclockwise in the sense of  FIG. 10A , at first narrowly, from a location near the junction of edges  320  and  329 , along and slightly spaced from edge  320 , where it becomes wider and then narrows, and narrowly along and spaced from edges  321  and  322 . Planar element  124  also includes a recess  442 , which extends counterclockwise in the sense of  FIG. 10A , narrowly, from a location near the junction of edges  325  and  326  and along and slightly spaced from edges  326 ,  327  and  328 . Planar element  124  also includes a recess  444 , which extends along and slightly spaced from edge  324 . Recesses  440 ,  442  and  444  cooperate with corresponding protrusions on planar element  126  to provide enhanced registration of the stack of interdigitated planar elements  124  and  126 . 
         [0048]    Planar element  124  also typically includes, at second side  302 , a recess  446  at inlet region  348  and a recess  450  at outlet region  352 . 
         [0049]    Planar element  124  also includes, at second side  302 , an array  460  of mutually spaced enhanced counter flow heat exchange (ECFHE) recesses  462  downstream of inlet region  448 . Each of mutually spaced recesses  462  preferably has a tapered inlet end  464  and a tapered outlet end  466 . 
         [0050]    Planar element  124  also includes, at second side  302 , an array  470  of mutually spaced enhanced counter flow heat exchange (ECFHE) recesses  472  upstream of outlet region  352 . Each of mutually spaced recesses  472  preferably has a tapered inlet end  474  and a tapered outlet end  476 . 
         [0051]    Planar element  124  also includes, at second side  302 , a plurality of mutual inner edge spacing recesses  480  preferably arranged at the sides of generally rectangular cutout  382  which accommodates core  102 . 
         [0052]    Planar element  124  also includes, at second side  302 , a plurality of outer edge recesses  490  preferably arranged along edges  323  and  329 . 
         [0053]    Turning now to generally planar element  126 , a first side thereof, designated by reference numeral  500 , is shown in  FIGS. 11A and 11B  and a second side thereof, designated by reference numeral  502 , is shown in  FIGS. 12A and 12B . Planar element  126  preferably has ten side edges, which are designated, counterclockwise with reference to  FIG. 11A , by reference numerals  520 ,  521 ,  522 ,  523 ,  524 ,  525 ,  526 ,  527 ,  528  and  529 . Planar element  126  is formed with a number of protrusions, which extend above the plane, designated by reference numeral  530 , of planar element  126 , in the sense of  FIG. 11A , to a height of approximately 3 mm and which will now be described in detail. Due to manufacture of planar elements  124  and  126  by vacuum forming, there are recesses which correspond with each of the protrusions. 
         [0054]    As seen in  FIGS. 11A &amp; 11B , first side  500  of planar element  126  includes an air flow blockage protrusion  540 , which extends counterclockwise, in the sense of  FIG. 11A , at first narrowly, from a location near the junction of edges  520  and  529 , along and slightly spaced from edge  520  where it becomes wider and then narrows, and narrowly along and spaced from edges  521  and  522 . Protrusion  540  serves to prevent air flow above plane  530  via edges  520 ,  521  and  522 . Planar element  126  also includes an air flow blockage protrusion  542 , which extends counterclockwise, in the sense of  FIG. 11A , narrowly, from a location near the junction of edges  525  and  526  and along and slightly spaced from edges  526 ,  527  and  528 . Protrusion  542  serves to prevent air flow above plane  530  via edges  526 ,  527  and  528 . Planar element  126  also includes an air flow blockage protrusion  544 , which extends along and slightly spaced from edge  524 . Protrusion  544  serves to prevent air flow above plane  530  via edge  524 . 
         [0055]    Planar element  126  also includes, at first side  500 , an air flow guiding protrusion  546  at what is typically an inlet region  548  above plane  530  and an air flow guiding protrusion  550  at what is typically an outlet region  552  above plane  530 . 
         [0056]    Planar element  126  also includes, at first side  500 , an array  560  of mutually spaced enhanced counter flow heat exchange (ECFHE) protrusions  562  downstream of inlet region  548 . Each of mutually spaced protrusions  562  preferably has a tapered inlet end  564  and a tapered outlet end  566 . 
         [0057]    Planar element  126  also includes at first side  500 , an array  570  of mutually spaced enhanced counter flow heat exchange (ECFHE) protrusions  572  upstream of outlet region  552 . Each of mutually spaced protrusions  572  preferably has a tapered inlet end  574  and a tapered outlet end  576 . 
         [0058]    Planar element  126  also includes, at first side  500 , a plurality of mutual inner edge spacing protrusions  580  preferably arranged at the sides of a generally rectangular cutout  582  which accommodates core  102 . 
         [0059]    Planar element  126  also includes, at first side  500 , a plurality of mutual outer edge spacing protrusions  590  preferably arranged along edges  523  and  529 . 
         [0060]    As seen in  FIGS. 12A &amp; 12B , second side  502  of planar element  126  includes a recess  640 , which extends clockwise in the sense of  FIG. 12A , at first narrowly, from a location near the junction of edges  520  and  529 , along and slightly spaced from edge  520  where it becomes wider and then narrows, and narrowly along and spaced from edges  521  and  522 . Planar element  126  also includes a recess  642 , which extends clockwise in the sense of  FIG. 12A , narrowly, from a location near the junction of edges  525  and  526  and along and slightly spaced from edges  526 ,  527  and  528 . Planar element  126  also includes a recess  644 , which extends along and slightly spaced from edge  524 . Recesses  640 ,  642  and  644  cooperate with corresponding protrusions on planar element  124  to provide enhanced registration of the stack of interdigitated planar elements  124  and  126 . 
         [0061]    Planar element  126  also typically includes, at second side  502 , a recess  646  at inlet region  548  and a recess  650  at outlet region  552 . 
         [0062]    Planar element  126  also includes, at second side  502 , an array  660  of mutually spaced enhanced counter flow heat exchange (ECFHE) recesses  662  downstream of inlet region  548 . Each of mutually spaced recesses  662  preferably has a tapered inlet end  664  and a tapered outlet end  666 . 
         [0063]    Planar element  126  also includes, at second side  502 , an array  670  of mutually spaced enhanced counter flow heat exchange (ECFHE) recesses  672  upstream of outlet region  552 . Each of mutually spaced recesses  672  preferably has a tapered inlet end  674  and a tapered outlet end  676 . 
         [0064]    Planar element  126  also includes, at second side  502 , a plurality of mutual inner edge spacing recesses  680  preferably arranged at the sides of generally rectangular cutout  582  which accommodates core  102 . 
         [0065]    Planar element  126  also includes, at second side  502 , a plurality of outer edge recesses  690  preferably arranged along edges  523  and  529 . 
         [0066]    Reference is now made to  FIG. 13 , which is a simplified partially exploded, pictorial illustration of part of the heat exchange assembly of  FIGS. 3A and 3B , showing typical air flows between adjacent embossed generally planar elements and to  FIGS. 14A ,  14 B,  14 C and  14 D, which are simplified illustrations of air flow through the heat exchange assembly of  FIGS. 3A and 3B , where  FIG. 14A  is a planar view and  FIGS. 14B ,  14 C and  14 D are sectional views taken along respective section lines B-B, C-C and D-D in  FIG. 14A . 
         [0067]      FIG. 13  shows airflow, designated generally by reference numeral  700 , between a first side  300  of a planar element  124  and a second side  502  of a planar element  126 . The second side  502  of planar element  126  is not seen in  FIG. 13 .  FIG. 13  also shows airflow, designated generally by reference numeral  702 , between a first side  500  of a planar element  126  and a second side  302  of a planar element  124 . The second side  302  of planar element  124  is not seen in  FIG. 13 . 
         [0068]    Considering airflow  700 , it is seen that a relatively planar flow of typically relatively humid air enters at an inlet region  348  above the plane  330  of planar element  124 , and which is bounded by adjacent second side  502  of planar element  126 . This flow is guided by one or more protrusions  346  into engagement with array  360  of protrusions  362  on planar element  124  and corresponding positioned array  670  of recesses  672  of planar element  126 . It is appreciated that the protrusions  362  partially seat within corresponding recesses  672  and together define an air flow passage between each recess  672  and the corresponding protrusion  362  partially seated therewithin. It is noted that the tapered ends  364  and  366  of the protrusions  362  and the tapered ends  674  and  676  of recesses  672  assist in defining these air flow passages. 
         [0069]    Downstream of arrays  360 , the air flow, which by this stage has been somewhat pre-cooled, as will be described hereinbelow, passes through the core plates  122  of core  102  in a generally planar flow, where it is substantially cooled, preferably to below the dew point. Downstream of core plates  122  of core  102 , the substantially cooled air flow passes through array  370  of protrusions  372  on planar element  124  and corresponding positioned array  660  of recesses  662  on planar element  126 . It is appreciated that the protrusions  372  partially seat within corresponding recesses  662  and together define an air flow passage between each recess  662  and the corresponding protrusion  372  partially seated therewithin. It is noted that the tapered ends  374  and  376  of the protrusions  372  and the tapered ends  664  and  666  of the recesses  662  assist in defining these air flow passages. 
         [0070]    Downstream of arrays  370 , the air flows, which have at this stage been somewhat warmed, as will be described hereinbelow, become joined into a relatively planar flow at outlet region  352  above the plane  330  of planar element  124 , and which is bounded by adjacent second side  502  of planar element  126 . This flow is guided by one or more protrusions  350 . 
         [0071]    Considering airflow  702 , it is seen that a relatively planar flow of typically relatively humid air enters at an inlet region  548  above the plane  530  of planar element  126 , and which is bounded by adjacent second side  302  of planar element  124 . This flow is guided by one or more protrusions  546  into engagement with array  560  of protrusions  562  on planar element  126  and corresponding positioned array  470  of recesses  472  on planar element  124 . It is appreciated that the protrusions  562  partially seat within corresponding recesses  472  and together define an air flow passage between each recess  472  and the corresponding protrusion  562  partially seated therewithin. It is noted that the tapered ends  564  and  566  of the protrusions  562  and the tapered ends  474  and  476  of the recesses  472  assist in defining these air flow passages. 
         [0072]    Downstream of arrays  560 , the air flow, which by this stage has been somewhat pre-cooled, as will be described hereinbelow, passes through the core plates  122  of core  102  in a generally planar flow, where it is substantially cooled, preferably to below the dew point. Downstream of core plates  122  of core  102 , the substantially cooled air flow passes through array  570  of protrusions  572  on planar element  126  and corresponding positioned array  460  of recesses  462  on planar element  124 . It is appreciated that the protrusions  572  partially seat within corresponding recesses  462  and together define an air flow passage between each recess  462  and the corresponding protrusion  572  partially seated therewithin. It is noted that the tapered ends  574  and  576  of the protrusions  572  and the tapered ends  464  and  466  of the recesses  462  assist in defining these air flow passages. 
         [0073]    Downstream of arrays  570 , the air flows, which have at this stage been somewhat warmed, as will be described hereinbelow, become joined into a relatively planar flow at outlet region  552  above the plane  530  of planar element  126 , and which is bounded by adjacent second side  302  of planar element  124 . This flow is guided by one or more protrusions  550 . 
         [0074]    Referring additionally to  FIGS. 14A-14D , it is seen that the air flows  700  and  702  between adjacent partially interdigitated planar elements  124  and  126  in the stack are in a generally counter flow mutual heat exchanging relationship, notwithstanding that the air flows are not entirely parallel, particularly at their respective inlet and outlet regions. It is an important feature of the invention that the air flows  700  and  702  are generally parallel in two dimensions as they pass through the core  102  and are generally parallel in three dimensions as they pass through the air flow passages defined between the protrusions and recesses of arrays  360  and  570  respectively and as they pass through the air flow passages defined between the protrusions and recesses of arrays  370  and  560  respectively. 
         [0075]    Thus it may be appreciated that enhanced heat exchange is provided between mutually counter airflows in the air flow passages defined between the protrusions and recesses of arrays  360  and  670  respectively and as they pass through the air flow passages defined between the protrusions and recesses of arrays  570  and  460  respectively, wherein three-dimensional counter flow is provided, and a lesser degree of heat exchange is provided therebetween in the inlet and outlet regions wherein only two-dimensional heat exchange engagement between adjacent planar air flows is provided. 
         [0076]    This can be seen graphically from a comparison of  FIGS. 14B and 14C .  FIG. 14B  shows a two-dimensional counter flow heat exchange relationship between adjacent generally planar air flows in the core  102  between adjacent plates  122  of the core  102 . 
         [0077]      FIG. 14C  shows a three-dimensional counter flow heat exchange relationship between adjacent generally planar air flows along the flow paths defined by arrays  360  and  670 .  FIG. 14C  also represents the three-dimensional counter flow heat exchange relationship between adjacent generally planar air flows along the flow paths defined by arrays  570  and  460 . 
         [0078]    It is appreciated that the heat exchange relationship represented in  FIG. 14C  is greatly enhanced as compared with that represented in  FIG. 14B  by virtue of the fact that nearly each flow shown in  FIG. 14C  is surrounded on four sides by a counterflowing flow path, whereas in  FIG. 14B , nearly each planar flow is surrounded on two sides by a counterflowing flow path. It is further appreciated that the protrusions and recesses defining the flow paths are downwardly inclined so to enhance ease of draining of condensate therefrom via edges  325  and  525  into base subassembly  130  for drainage and preferably utilization as drinking water. 
         [0079]    Realization of the highly efficient heat exchange structure shown in  FIG. 14C  is achieved in accordance with a particular feature of the present invention by the partial interdigitization of the protrusions and recesses described hereinabove and visualized in  FIG. 14D , which shows the arrangement of these flow paths in a view taken perpendicular to the planes  330  and  530  of the respective planar elements  124  and  126 . 
         [0080]    It will be appreciated by persons skilled in the art that the present invention is not limited to what has been particularly shown and described hereinabove. Rather the scope of the invention includes both combinations and subcombinations of the various features described hereinabove as well as modifications and variations thereof which would occur to persons skilled in the art upon reading the foregoing description and which are not in the prior art.