Dynamic cycle air conditioner with incremental dehumidification and stored water maintained at a temperature lower than the environment

Abstract

Water temperature conservation for increasing efficiency of an indirect evaporative cooling apparatus. A heat exchanger of the indirect evaporative cooling apparatus includes a dry passage separated from a wet passage by a membrane, the dry passage including an intake portion, an outlet portion, and a loop portion. Water captured from condensation during a dehumidification process can be stored and/or used to wet the wet passage of the heat exchanger to enhance evaporative function. Stored water can be maintained at a relatively lower temperature than the environment, helping to maintain a lower internal apparatus temperature and to further cool circulating air.

What is claimed is: 
     
         1 . An indirect evaporative cooler apparatus comprising:
 a heat exchanger comprising a dry passage and a wet passage, the wet passage comprising a nozzle coupled with an evaporative liquid reservoir and configured to wet the 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 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 move a first volume of air through the dry passage while dispensing evaporative liquid having a first temperature through the nozzle onto the hydrophilic surface to cool and dehumidify the first volume of air, and to dispense collected water condensed from the dehumidification of the first volume of air onto the hydrophilic surface to cool and dehumidify a second volume of air.   
     
     
         2 . The apparatus of  claim 1 , wherein the collected water is stored in an internal liquid reservoir disposed within a housing that contains the heat exchanger and coupled with the nozzle. 
     
     
         3 . The apparatus of  claim 2 , wherein the controller is adapted to increase pressure in the internal liquid reservoir to dispense the collected water upon detection of the collected water temperature being at or below a threshold value. 
     
     
         4 . The apparatus of  claim 1 , wherein the collected water is stored in the evaporative liquid reservoir. 
     
     
         5 . The apparatus of  claim 1 , further comprising a dry passage water nozzle configured to expel accumulated water from dehumidification of the first volume of air. 
     
     
         6 . A method of conserving water temperature for cooling air in an indirect evaporative cooler, the method comprising:
 having 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;   moving a first volume of air through the dry passage while dispensing an evaporative liquid having a first temperature onto the hydrophilic surface to cool and dehumidify the first volume of air;   collecting water condensed from the dehumidification of the first volume of air; and   dispensing the collected water onto the hydrophilic surface to cool and dehumidify a second volume of air.   
     
     
         7 . The method of  claim 6 , wherein collecting water comprises storing in an external reservoir operable to also store the evaporative liquid. 
     
     
         8 . The method of  claim 6 , wherein collecting water comprises storing in an internal reservoir disposed within a housing that contains the heat exchanger. 
     
     
         9 . The method of  claim 8 , wherein the dispensing comprises directing the collected water via a supply pipe to a wet passage nozzle, the supply pipe having an associated pressure valve for maintaining a dispensing rate. 
     
     
         10 . The method of  claim 9 , wherein the dispensing is controlled to occur when the collected water has a second temperature that is lower than the first temperature. 
     
     
         11 . A system for conserving water temperature for cooling 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 move a first volume of air through the dry passage while dispensing evaporative liquid having a first temperature through the nozzle onto the hydrophilic surface to cool and dehumidify the first volume of air, and to dispense collected water condensed from the dehumidification of the first volume of air onto the hydrophilic surface to cool and dehumidify a second volume of air.   
     
     
         12 . The system of  claim 11 , wherein the collected water is stored in an internal liquid reservoir disposed within a housing that contains the heat exchanger and coupled with the nozzle. 
     
     
         13 . The system of  claim 12 , wherein the controller is adapted to increase pressure in the internal liquid reservoir to dispense the collected water upon detection of the collected water temperature being at or below a threshold value. 
     
     
         14 . The system of  claim 11 , wherein the collected water is stored in the evaporative liquid reservoir. 
     
     
         15 . The system of  claim 11 , further comprising a dry passage water nozzle configured to expel accumulated water from dehumidification of the first volume of air.