Dynamic cycle air conditioner with incremental dehumidification incorporating a wet passage and a dry passage

Abstract

Incrementally cooling and dehumidifying a volume of air that is substantially at its dew point. Developing a pressure differential within an indirect evaporative cooler between a dry passage and ambient air and/or a wet passage and ambient air, to evaporate liquid outside the dry passage and condense liquid within the wet passage. A pressure differential can be developed by selectively pushing and/or blocking air at predetermined portions of the wet and dry passages.

What is claimed is: 
     
         1 . An indirect evaporative cooler apparatus comprising:
 a heat exchanger comprising a dry passage and a wet passage, the dry passage in thermodynamic communication with the wet passage and separated from the wet passage by a substantially liquid-impermeable membrane having a hydrophobic surface facing the dry passage and a hydrophilic surface facing the wet passage, the dry passage comprising an intake portion, an outlet portion, and a loop portion;   a mixing valve disposed in the dry passage and configured to selectively pass intake air from the intake portion, recirculation air from the loop portion, or a combination thereof;   a first fan disposed downstream of the mixing valve and adapted to move a first volume of air into and through the loop portion;   a diverting valve disposed in the dry passage and configured to selectively pass outlet air to the outlet portion, recirculation air to the mixing valve, or a combination thereof; and   a controller adapted to operate the mixing valve, the first fan, the diverting valve, and a combination thereof, to generate a barometric pressure differential in the heat exchanger sufficient to condense water from the first volume of air.   
     
     
         2 . The apparatus of  claim 1 , wherein the dry passage comprises air traps arranged to partially block the movement of a portion of the first volume of air through the loop portion and to develop a positive pressure in the loop portion relative to ambient pressure. 
     
     
         3 . The apparatus of  claim 1 , wherein the dry passage comprises a heat exchanger arranged to partially block the movement of a portion of the first volume of air through the loop portion and to develop a positive pressure in the loop portion relative to ambient pressure. 
     
     
         4 . The apparatus of  claim 1 , wherein to generate a barometric pressure differential comprises increasing barometric pressure in the dry passage, decreasing barometric pressure in the wet passage, or a combination thereof. 
     
     
         5 . The apparatus of  claim 4 , further comprising an enclosure fan and an enclosure valve associated therewith configured to develop a negative pressure in the wet passage. 
     
     
         6 . The apparatus of  claim 1 , wherein the controller is adapted to open the mixing valve for passing intake air and the diverting valve for passing outlet air upon detection of dry passage air temperature being below a threshold value. 
     
     
         7 . The apparatus of  claim 1 , wherein the first volume of air is circulated a number of loop circuits through the loop portion, the number of loop circuits being based on one of dry passage air temperature, dry passage air relative humidity, or a combination thereof. 
     
     
         8 . A method of conditioning air in an indirect evaporative air conditioner, the method comprising:
 circulating a first volume of air through a loop portion of a dry passage of an indirect evaporative air conditioner, the dry passage in thermodynamic communication with a wet passage configured to receive and to evaporate a liquid, the dry passage and the wet passage forming a heat exchanger;   determining a relative humidity of the first volume of air based on at least one of a barometric pressure and a temperature in the dry passage;   selectively generating a pressure differential in the heat exchanger upon the first volume of air determined to be substantially at its dew point, by increasing barometric pressure in the dry passage, decreasing barometric pressure in the wet passage, or a combination thereof, sufficient to condense water from the first volume of air.   
     
     
         9 . The method of  claim 8 , wherein the dry passage is maintained at a positive pressure range of 0.095-0.15 atm relative to ambient pressure. 
     
     
         10 . The method of  claim 9 , wherein the dry passage is maintained at a positive pressure substantially 0.1 atm relative to ambient pressure. 
     
     
         11 . The method of  claim 10 , wherein the wet passage is maintained at a negative pressure range of −0.15-−0.095 atm relative to ambient pressure. 
     
     
         12 . The method of  claim 11 , wherein the wet passage is maintained at a negative pressure substantially −0.1 atm relative to ambient pressure. 
     
     
         13 . The method of  claim 12 , wherein the dry passage is maintained at a positive pressure substantially 0.1 atm relative to ambient pressure. 
     
     
         14 . The method of  claim 13  further comprising a dry passage water nozzle configured to expel the condensed water from the first volume of air. 
     
     
         15 . The method of  claim 11 , wherein the negative pressure of the wet passage is developed by an enclosure fan and an enclosure valve associated therewith. 
     
     
         16 . The method of  claim 8 , wherein the dry passage comprises air traps arranged to partially block the movement of a portion of the first volume of air through the loop portion and to develop a positive pressure relative to ambient pressure. 
     
     
         17 . The method of  claim 8 , wherein the dry passage comprises a heat exchanger arranged to partially block the movement of a portion of the first volume of air through the loop portion and to develop a positive pressure relative to ambient pressure. 
     
     
         18 . A system for dehumidifying air, the system comprising:
 an evaporative liquid reservoir comprising a pressure valve and a channel adapted to transport evaporative liquid;   a heat exchanger comprising:
 a dry passage and a wet passage, the dry passage in thermodynamic communication with the wet passage and separated from the wet passage by a substantially liquid-impermeable membrane having a hydrophobic surface facing the dry passage and a hydrophilic surface facing the wet passage, the dry passage comprising an intake portion, an outlet portion, and a loop portion; 
 a nozzle coupled with the channel and configured to wet the wet passage for evaporative cooling of the substantially liquid-impermeable membrane; 
 a mixing valve disposed in the dry passage and configured to selectively pass intake air from the intake portion, recirculation air from the loop portion, or a combination thereof; 
 a first fan disposed downstream of the mixing valve and adapted to move a first volume of air into and through the loop portion; and 
 a diverting valve disposed in the dry passage and configured to selectively pass outlet air to the outlet portion, recirculation air to the mixing valve, or a combination thereof; and 
   a controller adapted to operate the mixing valve, the first fan, the diverting valve, and a combination thereof, to generate a barometric pressure differential in the heat exchanger sufficient to condense water from the first volume of air.   
     
     
         19 . The system of  claim 18 , wherein the dry passage comprises air traps arranged to partially block the movement of a portion of the first volume of air through the loop portion and to develop a positive pressure in the loop portion relative to ambient pressure. 
     
     
         20 . The system of  claim 18 , wherein the dry passage comprises a heat exchanger arranged to partially block the movement of a portion of the first volume of air through the loop portion and to develop a positive pressure in the loop portion relative to ambient pressure. 
     
     
         21 . The system of  claim 18 , wherein to generate a barometric pressure differential comprises increasing barometric pressure in the dry passage, decreasing barometric pressure in the wet passage, or a combination thereof. 
     
     
         22 . The system of  claim 21 , wherein the heat exchanger further comprises an enclosure fan and an enclosure valve associated therewith configured to develop a negative pressure in the wet passage. 
     
     
         23 . The system of  claim 18 , wherein the controller is adapted to open the mixing valve for passing intake air and the diverting valve for passing outlet air upon detection of dry passage air temperature being below a threshold value. 
     
     
         24 . The system of  claim 18 , wherein the first volume of air is circulated a number of loop circuits through the loop portion, the number of loop circuits being based on one of dry passage air temperature, dry passage air relative humidity, or a combination thereof.