Freeze tolerant fuel cell power plant with a direct contact heat exchanger

Abstract

A freeze tolerant fuel cell power plant ( 10 ) includes at least one fuel cell ( 12 ), a coolant loop ( 18 ) including a freeze tolerant accumulator ( 22 ) for storing and separating a water immiscible fluid and water coolant or water component, a direct contact heat exchanger ( 56 ) for mixing the water immiscible fluid and the water coolant within a mixing region ( 72 ) of the heat exchanger ( 56 ), a coolant pump ( 21 ) for circulating the coolant through the coolant loop ( 18 ), a radiator loop ( 84 ) for circulating the water immiscible fluid through the heat exchanger ( 56 ), and a radiator ( 86 ) for removing heat from the coolant. The plant ( 10 ) utilizes the water immiscible fluid during steady-state operation to cool the fuel cell and during shut down of the plant to displace water from the fuel cell ( 12 ) to the freeze tolerant accumulator ( 22 ).

1 . A direct contact heat exchanger ( 56 ) for removing heat from a water component, the direct contact heat exchanger comprising: 
 a. a water coolant inlet ( 70 ) secured to a mixing region ( 72 ) defined within the direct contact heat exchanger ( 56 ) and configured to direct a heated water component through the water coolant inlet ( 70 ) into the mixing region ( 72 );    b. a water immiscible fluid inlet ( 90 ) secured to the mixing region ( 72 ) of the direct contact heat exchanger and configured to direct a water immiscible fluid through the water immiscible fluid inlet ( 90 ) into the mixing region ( 72 );    c. a water immiscible fluid discharge ( 91 ) secured to a separation region ( 74 ) defined within the direct contact heat exchanger ( 56 ), wherein the separation region ( 74 ) is configured to be in direct fluid communication with the mixing region ( 72 ) of the heat exchanger ( 56 ); and,    d. a water coolant outlet ( 85 ) secured to a water region ( 76 ) defined within the heat exchanger ( 56 ), wherein the water region ( 76 ) is configured to be in direct fluid communication with the separation region ( 74 ) so that the water immiscible fluid mixes with the heated water component within the mixing region ( 72 ) removing heat from the water component, the heated water immiscible fluid flows out of the separation region ( 74 ) of the heat exchanger ( 56 ) through the water immiscible fluid discharge ( 91 ), and the cooled water component flows out of the water region ( 76 ) of the heat exchanger ( 56 ) through the water coolant outlet ( 85 ).    
   
   
       2 . The direct contact heat exchanger ( 56 ) of  claim 1  wherein the water coolant inlet ( 70 ) is secured in fluid communication with a coolant outlet ( 16 ) of a heat producing source, and the water coolant outlet ( 85 ) is secured in fluid communication with a coolant inlet ( 14 ) of the heat generating source.  
   
   
       3 . The direct contact heat exchanger ( 56 ) of  claim 2 , wherein the heat producing source is a fuel cell ( 12 ).  
   
   
       4 . The direct contact heat exchanger ( 56 ) of  claim 2  wherein the heat producing source is an internal combustion engine.  
   
   
       5 . The direct contact heat exchanger ( 56 ) of  claim 1  further comprising a radiator loop ( 84 ) secured in fluid communication between the water immiscible fluid discharge ( 91 ) and the water immiscible fluid inlet ( 90 ) of the direct contact heat exchanger ( 56 ), the radiator loop ( 84 ) including a radiator ( 86 ) configured to remove heat from the water immiscible fluid passing through the radiator ( 86 ), and a radiator pump ( 92 ) secured to the radiator loop ( 84 ) and configured to circulate the water immiscible fluid through the radiator ( 86 ) and the direct contact heat exchanger ( 56 ).  
   
   
       6 . The direct contact heat exchanger ( 56 ) of  claim 5 , wherein the radiator loop ( 84 ) further comprises a water immiscible fluid reservoir ( 94 ) secured in fluid communication with the radiator ( 86 ) and the direct contact heat exchanger ( 56 ), the reservoir ( 94 ) configured to supply the water immiscible fluid to the radiator loop ( 84 ) and direct contact heat exchanger ( 56 ).  
   
   
       7 . The direct contact heat exchanger ( 56 ) of  claim 1  further comprising a direct contact heat exchanger feed valve means ( 54 ) secured in fluid communication between the water coolant inlet ( 70 ) and a by-pass coolant passage ( 58 ), the feed valve means ( 54 ) configured for selectively directing the water component to flow through the water coolant inlet ( 70 ) into the direct contact heat exchanger or to flow through the by-pass coolant passage ( 58 ) by-passing the heat exchanger ( 56 ).