Chimney systems with integrated waste heat recovery and related methods

Abstract

A representative system includes: an inner stack defining a flow path to direct exhaust gasses from the exhaust air outlet of a heating appliance to an exhaust; an outer stack disposed about an exterior of the inner stack and being spaced therefrom to form a combustion air passage in a heat transfer relationship with the exterior of the inner stack; a combustion air opening disposed at the intake end of the outer stack configured to receive combustion air and provide the combustion air to the combustion air passage; an air dam positioned to terminate the combustion air passage; a combustion air conduit configured to direct the combustion air from the combustion air passage to the combustion air inlet of the heating appliance; wherein, in operation, heat is transferred from the exhaust gasses to the combustion air directed through the combustion air passage.

We claim: 
     
         1 . A chimney system with integrated waste heat recovery for use with a heating appliance, the heating appliance being located within a structure, the heating appliance having a combustion air inlet and an exhaust air outlet, the system comprising:
 an inner stack pneumatically communicating with the exhaust air outlet and extending in length to an exhaust, disposed exterior to the structure, the inner stack defining a flow path to direct exhaust gasses from the exhaust air outlet to the exhaust;   an outer stack extending along a portion of the length of the inner stack between an intake end and an appliance end, the outer stack being disposed about an exterior of the inner stack and being spaced therefrom to form a combustion air passage therebetween, the combustion air passage being annular in cross-section and in a heat transfer relationship with the exterior of the inner stack;   a combustion air opening disposed at the intake end of the outer stack, the combustion air opening being configured to receive combustion air and provide the combustion air to the combustion air passage;   an air dam disposed at the appliance end of the outer stack to terminate the combustion air passage; and   a combustion air conduit pneumatically communicating with the combustion air passage at the appliance end of the outer stack and upstream of the air dam, the combustion air conduit being configured to direct the combustion air from the combustion air passage to the combustion air inlet of the heating appliance;   wherein, in operation, heat is transferred from the exhaust gasses being directed from the heating appliance to the combustion air directed through the combustion air passage.   
     
     
         2 . The system of  claim 1 , wherein:
 the outer stack has a first aperture defining a first opening; and   an inlet of the combustion air conduit communicates with the combustion air passage via the first opening.   
     
     
         3 . The system of  claim 1 , further comprising a flow disruption assembly disposed along the flow path of the exhaust gasses, the flow disruption assembly having a first fin extending radially across the flow path, the first fin being inclined with respect to the flow path to disrupt the flow of the exhaust gasses. 
     
     
         4 . The system of  claim 3 , wherein:
 the flow disruption assembly is a first flow disruption assembly; and   the system further comprises a second flow disruption assembly disposed along the flow path of the exhaust gasses, the second flow disruption assembly being spaced from the first flow disruption assembly.   
     
     
         5 . The system of  claim 3 , wherein the flow disruption assembly has a second fin, the second fin being positioned downstream of the first fin with respect to the flow path of the exhaust gasses. 
     
     
         6 . The system of  claim 3 , wherein the flow disruption assembly has an axial shaft, and the first fin is attached to the axial shaft. 
     
     
         7 . The system of  claim 3 , wherein:
 the outer stack has a second aperture defining a second opening;   the inner stack has a first inner aperture defining a first inner opening, the first inner opening being aligned with the second opening;   the flow disruption assembly is mounted to an inner stack panel configured to selectively cover the first inner opening, the first fin being fixed in position relative to the inner stack panel.   
     
     
         8 . The system of  claim 7 , wherein:
 the flow disruption assembly is removably mounted to the inner stack via the inner stack panel; and   the outer stack has an outer door configured to provide selective access to the second opening to permit installation and removal of the flow disruption assembly.   
     
     
         9 . The system of  claim 1 , wherein the combustion air opening is annular. 
     
     
         10 . The system of  claim 1 , wherein the air dam is annular. 
     
     
         11 . The system of  claim 1 , wherein the air dam is positioned between an inner surface of the outer stack and an outer surface of the inner stack. 
     
     
         12 . A method for integrated waste heat recovery of a heating appliance, the heating appliance being located within a structure, the heating appliance having a combustion air inlet and an exhaust air outlet, the method comprising:
 providing an inner flow path to direct exhaust gasses from the exhaust air outlet of the heating appliance to an exhaust, which is disposed exterior to the structure;   providing a combustion air passage annular in cross section and disposed about an exterior of the inner flow path, the combustion air passage being in a heat transfer relationship with the inner flow path;   providing a combustion air flow path to direct the combustion air from the combustion air passage to the combustion air inlet of the heating appliance; and   transferring heat from the exhaust gasses of the heating appliance being directed along the inner flow path to the combustion air being directed in a counter-flow direction through the combustion air passage.   
     
     
         13 . The method of  claim 12 , wherein the combustion air opening is disposed within the structure. 
     
     
         14 . The method of  claim 12 , further comprising disrupting the flow of the exhaust gasses along the inner flow path to enhance heat exchange. 
     
     
         15 . The method of  claim 14 , wherein the disrupting is provided by a flow disruption assembly having a first fin, the flow disruption assembly being removably positioned along the inner flow path. 
     
     
         16 . The method of  claim 15 , further comprising:
 removing the flow disruption assembly;   cleaning the flow disruption assembly; and   reinstalling the flow disruption assembly.