Recuperator and combustor for use in external combustion engines and system for generating power employing same

Abstract

A combustor/recuperator assembly for use in an external combustion engine, such as a Stirling engine. The assembly includes a plurality of substantially hemispherical domed members positioned in nested uniaxial spaced relation, the plurality of substantially hemispherical domed members forming at least a first flow chamber and a second flow chamber, the first flow chamber for passing an incoming charge of air therethrough and the second flow chamber for passing an outgoing charge of combustion exhaust gases therethrough, wherein the second chamber is positioned to be effective to heat the incoming charge of air. Also provided is a system for producing power from a source of liquid fuel. The system is capable of producing up to about 5,000 watts of mechanical or electrical power.

1 . A combustor/recuperator assembly for use in an external combustion engine having a heater head, comprising: 
 a plurality of substantially hemispherical domed members positioned in nested uniaxial spaced relation, said plurality of substantially hemispherical domed members forming at least a first flow chamber and a second flow chamber, said first flow chamber for passing an incoming charge of air therethrough and said second flow chamber for passing an outgoing charge of combustion exhaust gases therethrough,    wherein said second chamber is positioned to be effective to heat the incoming charge of air.    
   
   
       2 . The assembly of  claim 1 , wherein said plurality of substantially hemispherical domed members comprises: 
 (a) an intake dome having an outer surface and an inner surface;    (b) a recuperator dome having an outer surface and an inner surface;    (c) an exhaust dome having an outer surface and an inner surface; and    (d) an inner dome having an outer surface and an inner surface,    wherein said recuperator dome is positioned between said inner surface of said intake dome and said outer surface of said exhaust dome and said outer surface of said inner dome is adjacent said inner surface said exhaust dome.    
   
   
       3 . The assembly of  claim 2 , further comprising refractory material affixed to said inner surface of said inner dome to insulate said intake dome, said recuperator dome and said exhaust dome from heat produced by combustion, whereby said refractory material enhances the ability to transfer heat to the outer surface of the external combustion engine heater head.  
   
   
       4 . The assembly of  claim 3 , wherein said refractory material is a lightweight, high-purity, alumina-silica fiber, having a duty rating of at least about 2300° F.  
   
   
       5 . The assembly of  claim 4 , wherein said refractory material has an approximate thermal conductivity value of at least about 0.8 BTU In/Hr/Ft 2  at a mean temperature of 1000° F.  
   
   
       6 . The assembly of  claim 4 , wherein the heater head of the external combustion engine is clad with a layer of copper to enhance heat transfer to the heater head.  
   
   
       7 . The assembly of  claim 1 , wherein the heater head of the external combustion engine is clad with a layer of copper to enhance heat transfer to the heater head.  
   
   
       8 . The assembly of  claim 2 , wherein said intake dome is fabricated from stainless steel having a wall thickness of from about 0.5 to about 1 mm.  
   
   
       9 . The assembly of  claim 2 , wherein said recuperator dome is fabricated from stainless steel having a wall thickness of from about 0.5 to about 1 mm.  
   
   
       10 . The assembly of  claim 2 , wherein said exhaust dome is fabricated from stainless steel having a wall thickness of about 1 mm.  
   
   
       11 . The assembly of  claim 2 , wherein said inner dome has a wall thickness of about 1 mm.  
   
   
       12 . A burner for an external combustion engine having a heater head, comprising: 
 (a) combustor/recuperator assembly for use in the external combustion engine having a heater head, said combustor/recuperator assembly including a plurality of substantially hemispherical domed members positioned in nested uniaxial spaced relation, said plurality of substantially hemispherical domed members forming at least a first flow chamber and a second flow chamber, said first flow chamber for passing an incoming charge of air therethrough and said second flow chamber for passing an outgoing charge of combustion exhaust gases therethrough;    (b) a fuel vaporizing device, said fuel vaporizing device including at least one capillary flow passage, said at least one capillary flow passage having an inlet end and an outlet end, said inlet end in fluid communication with a source of liquid fuel; and a heat source arranged along said at least one capillary flow passage, said heat source operable to heat the liquid fuel in said at least one capillary flow passage to a level sufficient to change at least a portion thereof from a liquid state to a vapor state and deliver a stream of substantially vaporized fuel from said outlet end of said at least one capillary flow passage; and    (d) a combustion chamber defined by an inner surface of said combustor/recuperator assembly and an outer surface of the heater head of the external combustion engine, said combustion chamber having an igniter for combusting the stream of substantially vaporized fuel and air, said combustion chamber in communication with said outlet end of said at least one capillary flow passage,    wherein said second chamber of said combustor/recuperator assembly is positioned to be effective to heat the incoming charge of air.    
   
   
       13 . The burner of  claim 12 , wherein said plurality of substantially hemispherical domed members comprises: 
 (a) an intake dome having an outer surface and an inner surface;    (b) a recuperator dome having an outer surface and an inner surface;    (c) an exhaust dome having an outer surface and an inner surface; and    (d) an inner dome having an outer surface and an inner surface,    wherein said recuperator dome is positioned between said inner surface of said intake dome and said outer surface of said exhaust dome and said outer surface of said inner dome is adjacent said inner surface said exhaust dome.    
   
   
       14 . The burner of  claim 13 , further comprising refractory material affixed to said inner surface of said inner dome to insulate said intake dome, said recuperator dome and said exhaust dome from heat produced by combustion, whereby said refractory material enhances the ability to transfer heat to the outer surface of the external combustion engine heater head.  
   
   
       15 . The burner of  claim 14 , wherein said refractory material is a lightweight, high-purity, alumina-silica fiber, having a duty rating of at least about 2300° F.  
   
   
       16 . The burner of  claim 15 , wherein said refractory material has an approximate thermal conductivity value of at least about 0.8 BTU In/Hr/Ft 2  at a mean temperature of 1000° F.  
   
   
       17 . The burner of  claim 15 , wherein the heater head of the external combustion engine is clad with a layer of copper to enhance heat transfer to the heater head.  
   
   
       18 . The burner of  claim 12 , wherein the heater head of the external combustion engine is clad with a layer of copper to enhance heat transfer to the heater head.  
   
   
       19 . The burner of  claim 13 , wherein said intake dome is fabricated from stainless steel having a wall thickness of from about 0.5 to about 1 mm.  
   
   
       20 . The burner of  claim 13 , wherein said recuperator dome is fabricated from stainless steel having a wall thickness of from about 0.5 to about 1 mm.  
   
   
       21 . The burner of  claim 13 , wherein said exhaust dome is fabricated from stainless steel having a wall thickness of about 1 mm.  
   
   
       22 . The burner of  claim 13 , wherein said inner dome has a wall thickness of about 1 mm.  
   
   
       23 . The burner of  claim 12 , wherein said heat source comprises a resistance-heating element.  
   
   
       24 . The burner of  claim 23 , wherein said at least one capillary flow passage comprises at least one capillary tube.  
   
   
       25 . The burner of  claim 24 , wherein said heat source comprises a section of said capillary tube heated by passing an electrical current therethrough.  
   
   
       26 . The burner of  claim 12 , further comprising a fuel source, said fuel source capable of delivering pressurized liquid fuel to said at least one capillary flow passage at a pressure of 100 psig or less.  
   
   
       27 . A method of generating power, comprising; 
 (a) inducing a flow of air of through an intake;    (b) supplying liquid fuel to at least one capillary flow passage;    (c) causing a stream of substantially vaporized fuel to pass through an outlet of the at least one capillary flow passage by heating the liquid fuel in the at least one capillary flow passage;    (d) combusting the air and vaporized fuel in a combustion chamber;    (e) exhausting a stream of combustion gases through an exhaust;    (f) exchanging heat from the stream of combustion gases exhausted in step (e) to the flow of air induced in step (a) through a recuperator; and    (g) converting heat produced by combustion of the vaporized fuel in the combustion chamber into mechanical and/or electrical power using an external combustion engine,    wherein the recuperator includes a plurality of substantially hemispherical domed members positioned in nested uniaxial relation, the plurality of substantially hemispherical domed members forming at least a first flow chamber and a second flow chamber, the first flow chamber for passing an incoming charge of air therethrough and the second flow chamber for passing an outgoing charge of combustion exhaust gases therethrough and the second chamber is positioned to be effective to heat the incoming charge of air.    
   
   
       28 . The method of  claim 27 , wherein the at least one capillary flow passage includes at least one capillary tube and the heat source comprises a resistance heating element or section of the capillary tube heated by passing an electrical current therethrough, the method further including flowing the liquid fuel through the capillary tube and vaporizing the liquid fuel by heating the tube.  
   
   
       29 . The method of  claim 27 , wherein the combustion chamber includes an igniter arranged to ignite the vaporized fuel, the method including igniting the vaporized fuel with the igniter.  
   
   
       30 . The method of  claim 27 , wherein the external combustion engine outputs up to 5000 watts of mechanical or electrical power, the method including generating power at one or more points in a range of up to 5000 watts of power with the conversion device.  
   
   
       31 . The method of  claim 27 , wherein the plurality of substantially hemispherical domed members comprises: 
 (a) an intake dome having an outer surface and an inner surface;    (b) a recuperator dome having an outer surface and an inner surface;    (c) an exhaust dome having an outer surface and an inner surface; and    (d) an inner dome having an outer surface and an inner surface,    wherein the recuperator dome is positioned between the inner surface of the intake dome and the outer surface of the exhaust dome and the outer surface of the inner dome is adjacent the inner surface the exhaust dome.    
   
   
       32 . The method of  claim 31 , further comprising refractory material affixed to the inner surface of the inner dome to insulate the intake dome, the recuperator dome and the exhaust dome from heat produced by combustion, whereby the refractory material enhances the ability to transfer heat to the outer surface of the external combustion engine heater head.  
   
   
       33 . The method of  claim 32 , wherein the refractory material is a lightweight, high-purity, alumina-silica fiber, having a duty rating of at least about 2300° F.  
   
   
       34 . The method of  claim 33 , wherein the refractory material has an approximate thermal conductivity value of at least about 0.8 BTU In/Hr/Ft 2  at a mean temperature of 1000° F.  
   
   
       35 . The method of  claim 33 , wherein the heater head of the external combustion engine is clad with a layer of copper to enhance heat transfer to the heater head.  
   
   
       36 . The method of  claim 27 , wherein the heater head of the external combustion engine is clad with a layer of copper to enhance heat transfer to the heater head.  
   
   
       37 . The method of  claim 28 , wherein the intake dome is fabricated from stainless steel having a wall thickness of from about 0.5 to about 1 mm.  
   
   
       38 . The method of  claim 28 , wherein the recuperator dome is fabricated from stainless steel having a wall thickness of from about 0.5 to about 1 mm.  
   
   
       39 . The method of  claim 28 , wherein the exhaust dome is fabricated from stainless steel having a wall thickness of about 1 mm.  
   
   
       40 . The method of  claim 28 , wherein the inner dome has a wall thickness of about 1 mm.