Burner vessel and fluid heater

Abstract

Disclosed is a burner vessel ( 5400 ) for a hybrid electric-combustible fuel fluid heater arranged to heat fluid in one or more fluid circuits. The vessel comprises a vessel housing ( 5401 ) containing: a combustible fuel burner ( 5405 ) arranged to burn combustible fuel; and one or more electric heating elements ( 5410 ) arranged to generate heat and transfer the heat to said fluid in one or more fluid circuits. The vessel further comprises: a first cold fluid inlet ( 5404 ) arranged to input relatively cold fluid to the vessel; a first hot fluid outlet arranged to output relatively hot fluid from the vessel; a first fluid duct ( 5403 ) extending between the first cold fluid inlet and the first hot fluid outlet and arranged to convey fluid through the vessel; and a flue ( 5407 ) arranged to convey waste combustion gas from the vessel. Both the combustible fuel burner and the one or more electric heating elements are arranged to heat fluid in the first fluid duct.

1 - 33 . (canceled) 
     
     
         34 . A burner vessel for a hybrid electric-combustible fuel fluid heater arranged to heat fluid in one or more fluid circuits, the vessel comprising a vessel housing containing:
 a combustible fuel burner arranged to burn combustible fuel;   one or more electric heating elements arranged to generate heat and transfer the heat to said fluid in one or more fluid circuits;   the vessel further comprising:   a first cold fluid inlet arranged to input relatively cold fluid to the vessel;   a first hot fluid outlet arranged to output relatively hot fluid to the one or more fluid circuits from the vessel;   a first fluid duct extending between the first cold fluid inlet and the first hot fluid outlet and arranged to convey fluid through the vessel;   a flue arranged to convey waste combustion gas from the vessel; and   wherein both the combustible fuel burner and the one or more electric heating elements are arranged to heat fluid in the first fluid duct.   
     
     
         35 . The burner vessel of  claim 34  wherein the housing further contains a burnt fuel heat exchanger arranged to transfer heat from the burnt fuel to said fluid in one or more fluid circuits. 
     
     
         36 . The burner vessel of  claim 34  wherein the duct comprises at least one duct wall through which heat is transferred from the burnt fuel to said fluid in one or more fluid circuits. 
     
     
         37 . The burner vessel of  claim 34  further comprising:
 a second cold fluid inlet arranged to input relatively cold fluid to the vessel; 
 a second hot fluid outlet arranged to output relatively hot fluid from the vessel; 
 a second fluid duct extending between the second cold fluid inlet and the second hot fluid outlet and arranged to convey fluid through the vessel; 
 wherein either or both of the combustible fuel burner and the one or more electric heating elements are arranged to heat fluid in the second duct. 
 
     
     
         38 . The burner vessel of any of  claim 35  wherein one or more of the electric heating elements is partially or completely embedded in: the burnt fuel heat exchanger; the at least one duct wall; or both. 
     
     
         39 . The burner vessel of any of  claim 35  comprising multiple distinct electric heating elements arranged to heat fluid in distinct sections of the first fluid duct. 
     
     
         40 . The burner vessel of any of  claim 35  wherein the heat exchanger, or the at least one duct wall, or both has a groove or grooves formed therein, the groove or grooves being arranged to locate the one or more electric heating elements. 
     
     
         41 . The burner vessel of any of  claim 35  wherein one or more of the electric heating elements is completely or partially located in the, any or each duct, and optionally spaced from the burnt fuel heat exchanger. 
     
     
         42 . The burner vessel of  claim 34  wherein one or more of the electric heating elements comprises a conductive heating element coating on any one or more of: an interior surface of an at least one duct wall; an exterior surface of the at least one duct wall; and a surface of the burnt fuel heat exchanger. 
     
     
         43 . The burner vessel of any of  claim 35  wherein the combustible fuel burner is arranged to burn fuel in a combustion zone, and the burnt fuel heat exchanger comprises a heat exchanger body, such as a cast heat exchanger body, and optionally wherein the heat exchanger body either:
 a) substantially surrounds the combustion zone; 
 b) comprises a block within or adjacent to the combustion zone, optionally near an upper part of the combustion zone; or 
 c) a combination of both a) and b). 
 
     
     
         44 . The burner vessel of any of  claim 35  wherein the burnt fuel heat exchanger comprises at least one heat exchanger protuberance, such as a heat exchanger fin, arranged to efficiently transfer heat from the burning fuel, and wherein optionally the at least one protuberance extends from the heat exchanger body towards the combustion zone and is in thermal communication with the heat exchanger body. 
     
     
         45 . The burner vessel of any of  claim 35  wherein the housing further comprises a cover, optionally a multi-layer cover, arranged to substantially surround the burnt fuel heat exchanger, and optionally the first fluid duct is defined between the cover and the burnt fuel heat exchanger. 
     
     
         46 . The burner vessel of  claim 45  wherein the multi-layer cover comprises at least one skin layer and at least one insulant layer. 
     
     
         47 . The burner vessel of any  claim 34  wherein the, any or each duct comprises:
 a channel defined between a wall of the heat exchanger and the cover, such as between an outer wall of the heat exchanger body and an inner surface of the cover; or 
 a sealed pipe arranged to pass through a space or channel between a wall of the heat exchanger and the cover; or 
 a channel defined entirely within the heat exchanger; or 
 a sealed pipe arranged to pass through a space or channel entirely within the heat exchanger; or 
 a sealed pipe passing through the housing, optionally through the combustion zone, and spaced from the heat exchanger; or 
 a sealed pipe passing through the housing, optionally through the combustion zone. 
 
     
     
         48 . The burner vessel of  claim 47  wherein the outer wall of the heat exchanger comprises a continuous open, optionally U-shaped or C-shaped, recess in its outer surface, wherein the channel is defined between the surface of the recess and the cover, and optionally wherein the channel extends in a spiral configuration around the outer wall of the heat exchanger from the first cold fluid inlet to the first hot fluid outlet, optionally downwardly in an in-use configuration. 
     
     
         49 . The burner vessel of  claim 47  wherein the, any or each of the electric heating elements is:
 located in or coated on or coated within the channel, optionally located near a base of the open recess, and further optionally spaced from the heat exchanger; or 
 partially or completely embedded in or coated on or coated within the heat exchanger near a base of the open recess; or 
 located in or coated on or coated within the channel, optionally located in contact with, or near to, the cover and spaced from a base of the open recess; or 
 partially or completely embedded in, or wrapped around, or coated on or coated within the at least one heat exchanger fin; or 
 integrally cast within or coated on or coated within the heat exchanger, such as within a channel, such as a spiral channel, defined entirely within the heat exchanger; or 
 wrapped around or coated on or coated within the, any or each duct; or 
 any combination thereof. 
 
     
     
         50 . The burner vessel of  claim 34  wherein the, any or each of the electric heating elements comprises any one or more of:
 a metal-sheathed, ceramic powder insulated cable with a nichrome element; 
 a spiraled wire element; 
 an encapsulated metal etched element, such as a silicone encapsulated metal etched element; 
 a pre-formed element having a desired shape profile; 
 an enamel coated element; 
 a conductive coating. 
 
     
     
         51 . The burner vessel of  claim 34  wherein the vessel housing further contains at least one baffle arranged to divert air heated by the fuel burner and arranged to increase thermal communication between the heated air and the at least one duct wall or the heat exchanger or both, and optionally wherein the, any or each electric element is partially or completely embedded within or coated on or coated within the at least one baffle or wrapped around the at least one baffle. 
     
     
         52 . The burner vessel of  claim 34  being arranged to heat water in first and second independent water circuits, the first circuit being arranged to provide heating water for a radiator circuit and the second circuit arranged to provide potable water, wherein the burner vessel is arranged to heat water for both circuits. 
     
     
         53 . The burner vessel of  claim 34  wherein the or each electric heating element is configured to be powered by any one or a combination of a DC power supply and an AC power supply. 
     
     
         54 . A fluid heater arranged to heat fluid in one or more fluid circuits, wherein the heater comprises:
 a burner vessel for a hybrid electric-combustible fuel fluid heater arranged to heat fluid in one or more fluid circuits, the vessel comprising a vessel housing containing:   a combustible fuel burner arranged to burn combustible fuel;   one or more electric heating elements arranged to generate heat and transfer the heat to said fluid in one or more fluid circuits;   the vessel further comprising:   a first cold fluid inlet arranged to input relatively cold fluid to the vessel;   a first hot fluid outlet arranged to output relatively hot fluid to the one or more fluid circuits from the vessel;   a first fluid duct extending between the first cold fluid inlet and the first hot fluid outlet and arranged to convey fluid through the vessel;   a flue arranged to convey waste combustion gas from the vessel; and   wherein both the combustible fuel burner and the one or more electric heating elements are arranged to heat fluid in the first fluid duct; and wherein the fluid heater further comprises a controller arranged to control the amount of heating supplied to said fluid in one or more fluid circuits by the combustible fuel burner and by the first heating element.   
     
     
         55 . The fluid heater of  claim 54  further comprising one or more of:
 a DC power supply, such as a battery pack, arranged to power the, any or each heating element, and optionally the DC power supply having a capacity of at least 0.5 kWh, further optionally at least 1 kWh, and yet further optionally at least 5 kWh or at least 20 k Wh; and 
 an AC power supply arranged to power the, any or each heating element. 
 
     
     
         56 . The fluid heater of  claim 55  wherein the controller is arranged to control supply of power to the electric heating element from the DC power supply, the AC power supply or both. 
     
     
         57 . The fluid heater of  claim 54 , wherein the controller is arranged to control the amount of heating supplied to the fluid based on or in response to any one or more control factors, the control factors comprising:
 amount of heating required;   fluid input temperature at an input point in the one or more fluid circuits;   fluid output temperature at an output point in the one or more fluid circuits;   fluid temperature at any predetermined point in the one or more fluid circuits;   amount of heating capacity available from the first heating element;   amount of heating capacity available from the combustible fuel burner;   instantaneous demand for heating fluid or potable water;   forecasted demand for heating fluid or potable water; and   flow rate of fluid to be heated; and optionally   wherein the fluid heater further comprises one or more sensors arranged to sense information relating to the one or more control factors and to provide said control factor information to the controller, and further optionally wherein the controller is configured to heat fluid primarily using the one or more electric heating elements, such as primarily via the DC power supply, when a demand for hot fluid is first detected.