High-thermal-mass hydronic furnace

Abstract

Various embodiments of the present invention are directed to a high-thermal-mass hydronic furnace. In one embodiment of the present invention, a high-thermal-mass hydronic furnace includes a firebox, an insulated outer casing, a fluid-transport system, and a draft air-flow system. Fuel input to the firebox is combusted on a high-thermal-mass ceramic refractory. Heat from the fuel combustion is transferred to fluid within the fluid-transport system, via an internal heat exchanger, and circulated to a location external to the insulated outer casing for subsequent distribution to an interconnected heat-delivery system. The draft air-flow system regulates the fuel combustion by controlling the amount of air passing through the firebox.

1 . A high-thermal-mass hydronic furnace comprising:
 an insulated outer casing;   a firebox within the insulating outer casing for combusting input fuel, the firebox including a ceramic refractory;   a draft air-flow system connecting the firebox to the environment external to the outer casing, the draft air-flow system including an air intake system for bringing air into the firebox and an exhaust vent for removing air from the firebox; and   a fluid-transport system interconnecting the firebox to the environment external to the outer casing, the fluid-transport system containing a circulatable heat-transfer fluid.   
   
   
       2 . The high-thermal-mass hydronic furnace of  claim 1  wherein the ceramic refractory is crucible-shaped. 
   
   
       3 . The high-thermal-mass hydronic furnace of  claim 1  wherein the firebox includes at least one hundred forty pounds of ceramic refractory per cubic foot of firebox. 
   
   
       4 . The high-thermal-mass hydronic furnace of  claim 1  wherein the insulation in the outer casing includes one or more of mineral wool; and
 a ceramic fiber blanket.   
   
   
       5 . The high-thermal-mass hydronic furnace of  claim 1  wherein the air intake system includes
 a number of air-input apertures in the high-thermal-mass ceramic refractory and outer casing;   a movable damper positioned over top of the air-input apertures on the outer casing; and   a damper actuator for moving the movable damper.   
   
   
       6 . The high-thermal-mass hydronic furnace of  claim 5  wherein the fluid-transport system includes a first aquastat for monitoring the temperature of the circulatable heat-transfer fluid and transmitting signals to the damper actuator. 
   
   
       7 . The high-thermal-mass hydronic furnace of  claim 5  wherein the movable damper may be placed in one of
 an open position wherein the air-input apertures are unobstructed; and   a closed position wherein the air-input apertures are obstructed.   
   
   
       8 . The high-thermal-mass hydronic furnace of  claim 7  wherein the draft air-flow system utilizes a draft to draw air into the firebox when the damper is in an open position and to vent air from the firebox out the exhaust vent. 
   
   
       9 . The high-thermal-mass hydronic furnace of  claim 1  wherein the exhaust vent is interconnected to a flue. 
   
   
       10 . The high-thermal-mass hydronic furnace of  claim 1  wherein the fluid-transport system includes an internal heat exchanger positioned above the firebox. 
   
   
       11 . The high-thermal-mass hydronic furnace of  claim 10  wherein the circulatable heat-transfer fluid in the internal heat exchanger becomes heated in response to the heat produced by fuel combusting in the firebox. 
   
   
       12 . The high-thermal-mass hydronic furnace of  claim 1  wherein the fluid-transport system includes a circulating pump for circulating the circulatable heat-transfer fluid in a continuous loop through the fluid-transport system. 
   
   
       13 . The high-thermal-mass hydronic furnace of  claim 1  wherein the fluid-transport system includes a flat panel heat exchanger for transferring heat from the circulatable heat-transfer fluid to an interconnected heat-delivery system. 
   
   
       14 . The high-thermal-mass hydronic furnace of  claim 1  wherein the fluid-transport system includes a second aquastat interfaced with a second heating source for coordinating usage between the high-thermal-mass hydronic furnace and the second heating source. 
   
   
       15 . The high-thermal-mass hydronic furnace of  claim 1  wherein the exhaust vent is positioned in proximity to the air-input apertures for pre-heating air input to the firebox. 
   
   
       16 . The high-thermal-mass hydronic furnace of  claim 1  wherein the exhaust vent is positioned in proximity to the fluid transfer system after the circulatable heat-transfer fluid has passed the flat panel heat exchanger, but before the circulatable heat-transfer fluid has reached the internal heat exchanger for pre-heating the circulatable heat-transfer fluid input to the internal heat exchanger. 
   
   
       17 . The high-thermal-mass hydronic furnace of  claim 1  wherein the combusted fuel is one of
 wood; and   biomass.   
   
   
       18 . A method for heating a room, the method comprising:
 providing a high-thermal-mass hydronic furnace, the high-thermal-mass hydronic furnace including a firebox within an insulated outer casing, the firebox having a ceramic refractory, and a fluid-transport system interconnecting the firebox to the environment external to the outer casing, the fluid-transport system containing a circulatable heat-transfer fluid;   igniting fuel input to the firebox;   transferring the heat from the combusting fuel in the firebox to the circulatable heat-transfer fluid;   transferring the heat from the circulatable heat-transfer fluid to an interconnected heat-delivery system.   
   
   
       19 . The method of  claim 18  wherein the firebox includes at least one hundred forty pounds of ceramic refractory per cubic foot of firebox, the ceramic refractory configured into a crucible shape. 
   
   
       20 . The method of  claim 18  wherein the high-thermal-mass hydronic furnace further includes a draft air-flow system connecting the firebox to the environment external to the insulated outer casing.