Resistance heater based air heating device

Abstract

Featured is a resistance heater air heating device that includes a low thermal conductivity enclosure and an electric resistance heater that is disposed within such an enclosure. In more particular embodiments, such an enclosure is configured so as to provide a high surface area which in combination with the heater heats the air passing through the enclosure. In more particular embodiments, the ceramic enclosure is configured and arranged so as to include a through aperture in which is disposed the electric resistance heater and through which the air flows along the length of the through aperture.

1 . A resistance heater air heating device, comprising
 a low thermal conductivity enclosure having a through aperture;   an electric resistance heater that is disposed within the low thermal conductivity enclosure through aperture;   wherein the electric resistance heater is configured and arranged so as to heat air flowing through the through aperture to at least a predetermined temperature within a predetermined time; and   wherein an inner surface of the low thermal conductivity enclosure is configured and arranged so as to provide a high surface area which in combination with the electric resistance heater heats the air passing through the through aperture.   
     
     
         2 . The resistance heater air heating device of  claim 1 , wherein the inner surface of the low thermal conductivity enclosure is configured with a plurality of convolutions that extend along the length of the enclosure. 
     
     
         3 . The resistance heater air heating device of  claim 2 , wherein the convolutions create a plurality of hills and valleys that extend along the length of the enclosure. 
     
     
         4 . The resistance heater air heating device of  claim 1 , wherein the inner surface of the low thermal conductivity enclosure is configured with a plurality of flutes that extend along the length of the enclosure. 
     
     
         5 . The resistance heater air heating device of  claim 4 , wherein the flutes create a plurality of hills and valleys that extend along the length of the enclosure. 
     
     
         6 . The resistance heater air heating device of  claim 1 , wherein the low thermal conductivity enclosure is composed of a material so the enclosure inner surface is heated by convection and radiation by the electrical resistance heater. 
     
     
         7 . The resistance heater air heating device of  claim 1 , further comprising an outer member that surrounds the ceramic enclosure. 
     
     
         8 . The resistance heater air heating device of  claim 1 , wherein the electric resistance heater is configured and arranged so as to reach a high temperature and has a high watt density. 
     
     
         9 . The resistance heater air heating device of  claim 1 , wherein the electric resistance heater is selected from a group consisting of hot surface igniters, silicon carbon igniters, silicon carbide hot surface igniters, ceramic/intermetallic hot surface igniters and silicon nitride igniters. 
     
     
         10 . The resistance heater air heating device of  claim 1 , wherein the electric resistance heater is selected from the group consisting of Norton Mini Igniters®, Norton CRYSTAR Igniters®, Surface Igniters, hot surface igniters, and I 2 R hot surface igniters. 
     
     
         11 . The resistance heater air heating device of any of  claims 8 - 10  wherein a heating element of the electric resistance heater is heated to a first temperature at or less than a first period of time and to a final temperature that is greater than the first temperature at or less than a second period of time. 
     
     
         12 . The resistance heater air heating device of  claim 11 , wherein the first temperature is at or above 1000° F. and the second temperature is at or about 2000° F. 
     
     
         13 . The resistance heater air heating device of  claim 1 , further comprising a plurality of low thermal conductivity enclosures and a plurality of electric resistance heaters, at least one electric heater for each low thermal conductivity enclosure. 
     
     
         14 . The resistance heater air heating device of  claim 1 , further comprising at least one electric heating device for each low thermal conductivity enclosure. 
     
     
         15 . A furnace for burning biomass fuel, comprising
 a combustion chamber in which is received the biomass fuel and combustion air; and   a resistance heater air heating device that is fluidly coupled to the combustion chamber such that at least some of the combustion air passes through the resistance heater air heating devices and onto the combustion chamber, the resistance heater air heating device including
 a low thermal conductivity enclosure having a through aperture; 
 an electric resistance heater that is disposed within the low thermal conductivity enclosure through aperture; 
 wherein the electric resistance heater is configured and arranged so as to heat combustion air flowing through the through aperture an onto the combustion chamber, to at least a predetermined temperature within a predetermined time; and 
 wherein an inner surface of the low thermal conductivity enclosure is configured and arranged so as to provide a high surface area which in combination with the electric resistance heater heats the air passing through the through aperture.