Fuel-fired appliance with thermoelectric-powered electric heating device

Abstract

A fluid heating device includes a housing defining an inner volume. A combustion chamber configured to produce heat via combustion such that heat produced by the combustion chamber is transferred to a fluid in the inner volume, and a flue is in fluid communication with the combustion chamber and in thermal communication with the inner volume. An electrical heating device is configured to provide heat to the fluid in the inner volume, and a thermoelectric generator is in electrical communication with the electrical heating device. The thermoelectric generator is connected to the flue such that a heat difference between the inner volume of the housing and the interior portion of the flue enables the thermoelectric generator to generate electricity.

What is claimed is: 
     
         1 . A fluid heating device comprising:
 a housing defining an inner volume;   a combustion chamber configured to produce heat via combustion such that at least some of the heat produced by the combustion chamber is transferred to a fluid in the inner volume;   a flue in fluid communication with the combustion chamber and extending through at least a portion of the inner volume, an interior portion of the flue being fluidly separated from the inner volume;   an electrical heating element configured to provide heat to the fluid in the inner volume; and   a thermoelectric generator in electrical communication with the electrical heating element, the thermoelectric generator being connected to the flue such that a heat difference between the inner volume of the housing and the interior portion of the flue enables the thermoelectric generator to generate electricity and provide the electricity to the electrical heating element for heating the fluid in the inner volume.   
     
     
         2 . The fluid heating device of  claim 1  further comprising a temperature sensor configured to detect a fluid temperature of the fluid in the inner volume. 
     
     
         3 . The fluid heating device of  claim 2  further comprising a controller in communication with at least one of the temperature sensor, the thermoelectric generator, the electrical heating element, and a burner device associated with the combustion chamber. 
     
     
         4 . The fluid heating device of  claim 3 , wherein the controller is configured to:
 receive temperature data from the temperature sensor, the temperature data being indicative of the fluid temperature; and   output instructions for the burner device to produce combustion in the combustion chamber in response to the temperature data indicating the fluid temperature is less than a temperature threshold.   
     
     
         5 . The fluid heating device of  claim 4 , wherein:
 the temperature threshold is a lower temperature threshold, and   the controller is further configured to:
 output instructions for the burner device to cease producing combustion in the combustion chamber in response to the temperature data indicating the fluid temperature is greater than or equal to an upper temperature threshold. 
   
     
     
         6 . The fluid heating device of  claim 4 , wherein when the burner device is producing combustion, hot combustion gases in the interior portion of the flue create a temperature differential between the interior portion of the flue and the inner volume of the housing, thereby enabling the thermoelectric generator to generate electricity, thereby powering the electrical heating element to also provide heat to the fluid in the inner volume. 
     
     
         7 . The fluid heating device of  claim 6 , wherein:
 the temperature threshold is a lower temperature threshold, and   the controller is further configured to:
 prevent the electrical heating element from causing the fluid temperature to exceed the temperature threshold by outputting instructions for the burner device to cease producing combustion in the combustion chamber in response to the temperature data indicating a fluid temperature that is greater than or equal to a lower temperature threshold. 
   
     
     
         8 . The fluid heating device of  claim 7 , wherein the lower temperature threshold is calculated based on a delayed amount of heat provided by the electrical heating element from electricity that will be generated by the thermoelectric generator after the burner device has ceased producing combustion. 
     
     
         9 . The fluid heating device of  claim 1 , wherein:
 the thermoelectric generator is a first thermoelectric generator, and   the fluid heating device further comprises a second thermoelectric generator connected to the flue such that the heat difference between the inner volume of the housing and the interior portion of the flue enables the second thermoelectric generator to generate electricity and provide the electricity to the electrical heating element for heating the fluid in the inner volume.   
     
     
         10 . The fluid heating device of  claim 9 , wherein the first and second thermoelectric generators are electrically connected in series. 
     
     
         11 . The fluid heating device of  claim 1 , wherein the fluid heating device is a furnace. 
     
     
         12 . The fluid heating device of  claim 1 , wherein the fluid heating device is a water heater. 
     
     
         13 . A fluid heating device comprising:
 a housing defining an inner volume;   a combustion chamber configured to produce heat via combustion such that at least some of the heat produced by the combustion chamber is transferred to a fluid in the inner volume;   a flue in fluid communication with the combustion chamber and in thermal communication with at least a portion of the inner volume, an interior portion of the flue being fluidly separated from the inner volume;   an electrical heating device configured to provide heat to the fluid in the inner volume; and   a thermoelectric generator in electrical communication with the electrical heating device, the thermoelectric generator being connected to the flue such that a heat difference between the inner volume of the housing and the interior portion of the flue enables the thermoelectric generator to generate electricity and provide the electricity to the electrical heating device for heating the fluid in the inner volume.   
     
     
         14 . The fluid heating device of  claim 13  further comprising a temperature sensor configured to detect a fluid temperature of the fluid in the inner volume. 
     
     
         15 . The fluid heating device of  claim 14 , wherein when burner device associated with the combustion chamber is producing combustion, hot combustion gases in the interior portion of the flue create a temperature differential between the interior portion of the flue and the inner volume of the housing, thereby enabling the thermoelectric generator to generate electricity, thereby powering the electrical heating device to also provide heat to the fluid in the inner volume. 
     
     
         16 . The fluid heating device of  claim 13 , wherein:
 the thermoelectric generator is a first thermoelectric generator, and   the fluid heating device further comprises a second thermoelectric generator connected to the flue such that the heat difference between the inner volume of the housing and the interior portion of the flue enables the second thermoelectric generator to generate electricity and provide the electricity to the electrical heating device for heating the fluid in the inner volume.   
     
     
         17 . The fluid heating device of  claim 16 , wherein the first and second thermoelectric generators are electrically connected in series. 
     
     
         18 . The fluid heating device of  claim 13 , wherein the fluid heating device is a furnace. 
     
     
         19 . The fluid heating device of  claim 13 , wherein the fluid heating device is a water heater.