Condensing Side-Arm Water Heater

Abstract

An apparatus for providing a condensing side-arm water heater with improved efficiency. The condensing side-arm element recirculates exhaust gases into heating the cooler part of a water heater tank by the thermosiphon (or buoyancy) effect in a counterflow configuration, thus increasing efficiency of the water heater.

1 . A condensing side-arm water heater, comprising:
 a) a tank;   b) a recirculation pipe fluidly connected to an upper and lower aperture in the tank;   c) a heat exchanger in thermal contact with the recirculation pipe;   d) a burner for heating the tank, that produces heated combustion products;   e) an exhaust system that take the heated combustion products from the burner, and transfers a fraction of the heat to the heat exchanger;
 i) the exhaust system comprising:
 (1) an exhaust fan blower; 
 (2) a drip pipe; 
 (3) and an air inlet; 
 
   f) whereby the heated combustion products pass through the exhaust system, condensing water vapor from the combustion byproducts, and expelling the condensed water vapor through the drip pipe.   
   
   
       2 . The condensing side-arm water heater of  claim 1 , comprising:
 a) an upper and lower thermostat that allow control of the condensing side-arm water heater.   
   
   
       3 . The condensing side-arm water heater of  claim 1 , comprising:
 a) an insulating material disposed about the exhaust system, so as to increase thermal efficiency.   
   
   
       4 . The condensing side-arm water heater of  claim 1 , wherein the burner comprises:
 a) a low NO x  burner.   
   
   
       5 . The condensing side-arm water heater of  claim 4 , wherein the low NO x  burner comprises:
 a) a combustion zone;   b) a pilot mounted adjacent to said combustion zone, including,   c) a mixer for premixing fuel and oxidant to produce a feed gas;   d) a mechanical swirler located downstream from said mixer and capable of receiving a premixed feed gas from said mixer, said swirler including
 i) a central passage having an entrance for accepting a portion of said feed gas, a flow balancing insert that introduces additional pressure drop beyond that occurring in the central passage without said flow balancing insert, and an exit aligned to direct said portion of said feed gas into a second combustion zone, and 
 ii) an annular passage about said central passage having an entrance for accepting a second portion of said feed gas, one or more vanes oriented to impart angular momentum to feed gas exiting said annular passage and an exit aligned to direct said second portion of said feed gas into the second combustion zone, 
 wherein said swirler does not induce recirculation in said feed gas, and 
 wherein said second combustion zone is capable of supporting combustion of said premixed feed gas; and 
 wherein said pilot is capable of igniting a fuel mixture provided to said combustion zone.