Water production system and method with air bypass

Abstract

An apparatus and method for condensing water vapor in air to extract liquid water includes an air duct, an air movement device, and a refrigeration system. The air duct has an entry port, an intermediate port, and an exit port; while the refrigeration system includes at least one evaporator and condenser within the air duct. The air movement device may be a fan within the air duct, to cause air flow through the condenser and out the exit port. The air has a dew point, and the evaporator temperature is at that dew point or less, to cause liquid water to condense on the evaporator's exterior surface. The intermediate port of the air duct is between the evaporator and condenser, such that air can enter the air duct by at least two paths: through the entry port and evaporator, and through the intermediate port which bypasses the evaporator.

1 . An apparatus for extracting water from air, comprising:
 an air duct having an entry port, an intermediate port, and an exit port;   a refrigeration system, including an evaporator and a condenser within the air duct, the evaporator having a temperature of at most a dew point of air contacting the evaporator, to cause liquid water to condense on an exterior surface of the evaporator;   the air duct defining:
 a first air flow path sequentially through the entry port, evaporator, condenser, and exit port; and 
 a second air flow path sequentially through the intermediate port, condenser, and exit port; and 
   an air movement device disposed within the air duct, operable to draw air through the air duct along the first and second air flow paths.   
   
   
       2 . The apparatus according to  claim 1 , further comprising a bypass valve affixed to the intermediate port, selectively operable between an open position and a closed position. 
   
   
       3 . The apparatus according to  claim 2 , wherein the bypass valve is selectively operable to a plurality of positions between the open position and the closed position. 
   
   
       4 . The apparatus according to  claim 2 , further comprising a controller adapted to operate the bypass valve according to a temperature and a humidity of the air. 
   
   
       5 . The apparatus according to  claim 4 , wherein the controller is operative to open the bypass valve when the air exceeds a selected temperature, and to at least partially close the bypass valve when the air falls below the selected temperature. 
   
   
       6 . The apparatus according to  claim 1 , further comprising three additional evaporators and three additional condensers, such that four sets of an evaporator and condenser are orthogonally arranged to define a rectangular air passage through the air movement device. 
   
   
       7 . The apparatus according to  claim 6 , wherein the exit port is positioned at one end of the rectangular passage. 
   
   
       8 . The apparatus according to  claim 1 , further comprising a compressor, a first and second expansion valve, an additional evaporator, and an additional condenser, wherein a refrigerant in the refrigeration system passes sequentially from the compressor to the condenser, the additional condenser, the expansion valves, the evaporators, and then returns to the compressor. 
   
   
       9 . The apparatus according to  claim 8 , wherein the evaporator and additional evaporator are connected to the refrigeration system in parallel, and the condenser and additional condenser are connected to the refrigeration system in series. 
   
   
       10 . The apparatus according to  claim 8 , wherein a refrigerant in the refrigeration system exits the condenser in a gaseous state and exits the additional condenser in a liquid state such that the condenser acts as a de-superheater. 
   
   
       11 . The apparatus according to  claim 8 , further comprising a second refrigeration system, the second refrigeration system including a second compressor, a third expansion valve, and a fourth expansion valve, wherein the first and second refrigeration systems define separate closed-loop refrigerant paths. 
   
   
       12 . The apparatus according to  claim 2 , wherein the air duct further comprises an additional intermediate port, the intermediate port providing a conditional air bypass, the additional intermediate port providing a persistent air bypass. 
   
   
       13 . The apparatus according to  claim 1 , wherein the condenser has a greater capacity for air flow than the evaporator. 
   
   
       14 . The apparatus according to  claim 1 , further comprising:
 an ice sensor, the ice sensor sensing ice buildup on the evaporator; and   a switch coupled to the ice sensor to shut off the refrigeration system when ice is present.   
   
   
       15 . The apparatus according to  claim 1 , further comprising a water collection vessel positioned proximate to the evaporator for collecting water. 
   
   
       16 . The apparatus according to  claim 1 , wherein the air movement device is a fan. 
   
   
       17 . An apparatus for extracting water from air, comprising:
 an air duct having an entry port, an intermediate port, and an exit port;   a refrigeration system, the refrigeration system including an evaporator and a condenser within the air duct, the evaporator having a temperature of at most a dew point of air contacting the evaporator to cause liquid water to condense on an exterior surface of the evaporator;   an air movement device disposed within the air duct, operable to cause air to flow through the condenser and out the exit port; and   the intermediate port being positioned between the evaporator and condenser, such that air can enter the air duct: (i) through the entry port and evaporator, and (ii) through the intermediate port, bypassing the evaporator.   
   
   
       18 . A method of using a water production system to extract water from air, the water production system including a refrigeration system having a cooling element, and an air duct having an entry port, an intermediate port, and an exit port, the method comprising:
 operating the air movement device to cause air to flow along:
 a first flow path into the entry port, through the cooling element, and out the exit port; and 
 a second flow path into the intermediate port, and out the exit port, thus bypassing the cooling element; 
   operating the refrigeration system to cause the cooling element to maintain a temperature of at most a dew point of air contacting the cooling element;   condensing liquid water on an exterior surface of the cooling element; and   collecting the liquid water.   
   
   
       19 . The method according to  claim 18 , wherein the water production system also includes a bypass valve located proximate the intermediate port, wherein operating the air movement device further comprises:
 determining a temperature of air;   opening the bypass valve when the temperature exceeds a selected temperature to allow air to flow into the intermediate port; and   at least partially closing the bypass valve to resist flow of air into the intermediate port when the temperature falls below the selected temperature.   
   
   
       20 . The method according to  claim 18 , wherein the water production system also includes an additional intermediate port and bypass valve located proximate the intermediate port, wherein operating the air movement device further comprises:
 selectively opening and closing the bypass valve to allow and resist air flow into the intermediate port, respectively, and maintaining the additional intermediate port in an open position.