Method and Materials for Improving Evaporative Heat Exchangers

Abstract

A corrugated laminate material ( 44 ) for use in an evaporative heat exchanger, said material including a water retaining medium having a wettable surface ( 40 ) and an opposed vapour resistant surface ( 42 ).

1 . A corrugated laminate material for use in an evaporative heat exchanger, said corrugated laminate material including a water retaining medium having a wettable surface and an opposed vapour resistant surface. 
   
   
       2 . The corrugated laminate material as claimed in  claim 1 , wherein the corrugations are equi-sized. 
   
   
       3 . The corrugated laminate material as claimed in  claim 1 , wherein the corrugations are mutually parallel at a common angle across the length of at least a portion of said corrugated laminate material. 
   
   
       4 . The corrugated laminate material as claimed in  claim 1 , wherein the corrugations are at varying angles across the length of at least a portion of said corrugated laminate material. 
   
   
       5 . The corrugated laminate material as claimed in  claim 1 , wherein the water retaining medium is selected from treated wettable paper, moulded paper fibre slurry, wettable particulate sintered polymers and metallic or polymer films having treated or modified surfaces to promote wetting. 
   
   
       6 . The corrugated laminate material as claimed in  claim 1  wherein the vapour resistant surface is formed from a plastic film liquid polymer or vapour resistant treatment applied to one surface of the water retaining medium. 
   
   
       7 . A method of making a corrugated laminate material for use in an evaporative heat exchanger comprising the steps of:
 providing a planar sheet of water retaining medium; and   forming corrugations by the planar sheet of water retaining medium through corrugating rollers.   
   
   
       8 . The method as claimed in  claim 7 , further comprising the step of applying a vapour resistant surface during formation of the corrugations. 
   
   
       9 . The method as claimed in  claim 7 , further comprising the step of applying a vapour resistant surface before or after formation of the corrugations. 
   
   
       10 . The method as claimed in  claim 8 , further comprising the step of applying the vapour resistant surface by hot calendaring it onto or adhering it to the planar sheet while the planar sheet is being fed through the rollers. 
   
   
       11 . The method as claimed in  claim 9 , further comprising the step of spraying the vapour resistant surface onto the planar sheet. 
   
   
       12 . A heat exchange element for a core for use in an evaporative heat exchanger formed from at least one sheet of corrugated laminate material, wherein the at least one sheet of corrugated laminate material having first and second sides, said first side includes a water retaining medium having a wettable media and a said second side includes a vapour resistant surface, the corrugated laminated material being folded to form at least fold such that the interior of each fold forms a wettable surface passage or a vapour resistant channel. 
   
   
       13 . The heat exchange element of  claim 12 , further comprising a plurality of elements wherein each element includes said sheet and where the respective sheet in said plurality of elements are placed side by side in a substantially parallel relationship such that adjacent surfaces of each sheet form a wettable surface passage or a vapour resistant passage. 
   
   
       14 . The heat exchange element of  claim 12 , formed from at least two of said sheets of corrugated laminate material, wherein the two sheets are joined to form a passage having corrugated walls for airflow therethrough and wherein the corrugations on opposite sides of the passage are at intersecting angles. 
   
   
       15 . The heat exchange element as claimed in  claim 14 , wherein the passage is bounded by vapour resistant surfaces. 
   
   
       16 . The heat exchange core including a plurality of heat exchange elements as claimed in  claim 14  stacked side by side such that passages between the stacked elements provide wettable surface passages. 
   
   
       17 . A method of making a heat exchange core comprising the steps of:
 providing a plurality of pairs of sheets of corrugated laminate material each sheet having first and second sides, said first side includes a water retaining medium having a wettable media and a said second side includes a vapour resistant surface;   spacing said plurality of pairs of sheets in a substantially parallel spaced apart relationship;   forming a plurality of pockets from pairs of said sheets where the inner surfaces of each pocket are vapour resistant surfaces;   sealing adjacent edges of each pair of substantially parallel spaced apart sheets together to form open-ended pockets; and   stacking said pockets in a substantially parallel relationship to form wettable surface airflow passages between each pair of adjacent pockets.   
   
   
       18 . A method of effecting heat exchange between counter current airflows in a heat exchanger comprising the steps of:
 providing a heat exchange core within the heat exchanger comprising wet and dry airflow channels in counter flow; and   forming said wet and dry airflow channels with corrugated walls;   wherein entry air is passed down the dry airflow channels to exit as conditioned air, a portion of the exit air being reversed to pass through the wet channels and effect heat exchange between the dry and wet airflow channels before being exhausted.   
   
   
       19 . (canceled) 
   
   
       20 . A method of operating an evaporative cooler comprising the steps of:
 providing a heat exchange core having adjacent wet and dry airflow channels;   orienting said wet and dry airflow channels to counter current airflow heat exchange relationship;   supplying water to the wet channels in a descending flow pattern;   supplying water to the wet channels over a plurality of segments from an air entry end to an air outlet end of said heat exchange core during operation of said evaporative cooler; and   circulating water through each segment relatively separately from adjacent segments such that an appropriate temperature gradient is established from an air inlet end to an air outlet end of the core by maintaining different circulating water temperatures in each segment.   
   
   
       21 . A method of operating an evaporative cooler comprising the steps of:
 providing a heat exchange core adapted for heat exchange airflow therethrough via a plurality of heat exchange channels, at least some of said channels being wet channels;   applying water to a wettable material in the wet channels, the wettable material retaining the water;   applying water to the wet channels in an intermittently and generally uniformly descending flow pattern across the entire core; and   repeating the application of water to the wet channels of the core before the wettable material has dried out.   
   
   
       22 . The method as claimed in  claim 20 , wherein the step of providing the heat exchange core includes a heat exchange core comprising a plurality of elements wherein each element includes a sheet having first and second sides, said first side includes a water retaining medium having a wettable media and a said second side includes a vapour resistant surface and where the respective sheet in said plurality of elements are placed side by side in parallel such that adjacent surfaces of each sheet form a wettable surface passage or a vapour resistant passage. 
   
   
       23 . An evaporative cooler including a heat exchange core comprising:
 a plurality of elements wherein each element includes a sheet of corrugated laminate material having first and second sides, said first side includes a water retaining medium having a wettable media and a said second side includes a vapour resistant surface;   the respective sheet in each of said plurality of elements are placed side by side in a substantially parallel relationship such that adjacent surfaces of each sheet form a wettable surface passage or a vapour resistant passage;   a water distribution system including a plurality of water distributors for wetting the wettable surfaces, passages, or channels, said water distributors being positioned above the core and disposed in spaced apart parallel relation transversely of the core relative to an airflow direction through the core, each water distributor being located within a respective space above the core separate from adjacent water distributor spaces, each water distributor being supplied from a respective reservoir, and further including flow restriction means at an airflow exit of the vapour resistant channels for effecting counter flow of a portion of the exit air through the wet channels to an exhaust.