Asymmetric Dimple Tube for Gas Heat

Abstract

A heat exchanger tube for a gas furnace is provided. The heat exchanger tube may include an inlet, an outlet and one or more asymmetric dimple pairs disposed between the inlet and the outlet. The inlet and the outlet may form a passageway through the heat exchanger tube for receiving a heated combustion gas. Each asymmetric dimple pair may provide a first dimple and an opposing second dimple. The first and second dimples may be configured to at least partially constrict flow of the gas therethrough. Together, the first and second dimples may form an upstream section, a downstream section and a merge point.

1 . A heat exchanger tube for a gas furnace, comprising:
 an inlet and an outlet forming a passageway therethrough for receiving a gas; and   one or more asymmetric dimple pairs disposed between the inlet and the outlet, each asymmetric dimple pair including a first dimple and an opposing second dimple, the first and second dimples being configured to at least partially constrict flow of the gas therethrough, each asymmetric dimple pair forming an upstream section, a downstream section and a merge point.   
     
     
         2 . The heat exchanger tube of  claim 1  further comprising at least one bend disposed between to the inlet and the outlet so as to form at least a first pass between the inlet and the bend and a second pass between the bend and the outlet. 
     
     
         3 . The heat exchanger tube of  claim 2 , wherein the asymmetric dimple pairs are disposed along the second pass. 
     
     
         4 . The heat exchanger tube of  claim 1 , wherein the upstream section is substantially shorter than a length of the downstream section. 
     
     
         5 . The heat exchanger tube of  claim 1 , wherein respective lengths of the upstream and downstream sections are at least partially dependent on a cross-sectional diameter of the heat exchanger tube. 
     
     
         6 . The heat exchanger tube of  claim 1 , wherein each of the first and second dimples is formed as an indentation in a surface of the heat exchanger tube. 
     
     
         7 . The heat exchanger tube of  claim 1 , wherein a plurality of asymmetric dimple pairs are linearly disposed along a length of the heat exchanger tube. 
     
     
         8 . The heat exchanger tube of  claim 1 , wherein a plurality of asymmetric dimple pairs are nonlinearly disposed along a length of the heat exchanger tube. 
     
     
         9 . The heat exchanger tube of  claim 1 , wherein a plurality of asymmetric dimple pairs are spirally disposed along a length of the heat exchanger tube. 
     
     
         10 . A heat exchanger tube for a gas furnace, comprising:
 an inlet and an outlet forming a passageway therethrough for receiving a gas; and   at least two rows of asymmetric dimples disposed along opposing sides of the heat exchanger tube so as to form a plurality of dimple pairs, each dimple pair being configured to at least partially constrict flow of the gas therethrough, each dimple pair forming an upstream section, a downstream section and a merge point, the upstream section being shorter in length than the downstream section.   
     
     
         11 . The heat exchanger tube of  claim 10  further comprising at least one bend disposed between to the inlet and the outlet so as to form at least a first pass between the inlet and the bend and a second pass between the bend and the outlet. 
     
     
         12 . The heat exchanger tube of  claim 11 , wherein the rows of asymmetric dimples are disposed along the second pass. 
     
     
         13 . The heat exchanger tube of  claim 10 , wherein respective lengths of the upstream and downstream sections are at least partially dependent on a cross-sectional diameter of the heat exchanger tube. 
     
     
         14 . The heat exchanger tube of  claim 10 , wherein each asymmetric dimple is formed as an indentation in a surface of the heat exchanger tube. 
     
     
         15 . A heating and cooling system, comprising:
 a ventilation duct configured to communicate external air with an interior space;   at least one fan configured to draw the external air through the ventilation duct and toward the interior space; and   at least one heat exchanger tube disposed within the ventilation duct and proximate to the fan, the heat exchanger tube being configured to receive a heated combustion gas therethrough and heat the external air supplied by the fan, the heat exchanger tube having a plurality of asymmetric dimple pairs at least partially disposed along a length of the heat exchanger tube, each asymmetric dimple pair having two opposing dimples configured to at least partially constrict flow of the gas therethrough, each asymmetric dimple forming an upstream section, a downstream section and a merge point, the upstream section being shorter in length than the downstream section.   
     
     
         16 . The heating and cooling system of  claim 15  further being configured as a roof-top unit. 
     
     
         17 . The heating and cooling system of  claim 15  further comprising a burner disposed proximate to an inlet of the heat exchanger tube. 
     
     
         18 . The heating and cooling system of  claim 15  further comprising an induction blower disposed proximate to an outlet of the heat exchanger tube. 
     
     
         19 . The heating and cooling system of  claim 15 , wherein the heat exchanger tube includes at least one bend so as to form at least a first pass between the inlet and the bend and a second pass between the bend and the outlet. 
     
     
         20 . The heating and cooling system of  claim 19 , wherein the asymmetric dimple pairs are distributed along the second pass.