Venturi for Heat Transfer

Abstract

Heat pumps consume power in order to transfer heat from a source to a higher-temperature sink. This invention enables spontaneous heat transfer from a heat source to a small portion of the generally warmer working fluid that is cooled locally by the Bernoulli effect to a temperature below that of the heat source. The Bernoulli effect occurs in a Venturi shaped duct shaped to maintain attached flow. Heat-transfer efficiency is improved by restriction of the heat transfer to a small portion of the Venturi in which the flow temperature, velocity, pressure gradient and the Nusselt effect enhance heat transfer. Within this region, heat transfer is maximized by a thermally conducting grid extending across the Venturi neck.

1 . A solid heat-transfer Venturi duct structure capable of guiding a fluid flow, wherein
 the cross-sectional area of said duct varies along its axis and   said variation of said cross-sectional area possesses at least one local minimum and   the walls of said duct are thermally insulating, except   in at least one thin, thermally conducting cross-sectional portion of said duct wall located close to said minimum-area cross section, and   a thermal conductor connecting said thermally conducting portion of said duct wall to a heat source   
   
   
       2 . A heat-transfer Venturi duct structure as in  claim 1 , comprising at least one thermally conducting fin extending from said thermally conducting portion of said duct wall into the interior of said duct structure. 
   
   
       3 . A heat-transfer Venturi duct structure as in  claim 2 , wherein said fin extends across said duct 
   
   
       4 . A heat-transfer Venturi duct structure as in  claim 2 , wherein multiple said thermally conducting fins form a thermally conducting grid within said thermally conducting cross-sectional portion of said duct. 
   
   
       5 . A heat-transfer Venturi duct structure as in  claim 2 , wherein said fin is shaped to minimize aerodynamic drag on a fluid flowing through said heat-transfer duct structure. 
   
   
       6 . A heat-transfer Venturi duct structure as in  claim 2 , wherein said fin is aligned with the stream lines of said fluid flowing through said heat-transfer duct structure for the purpose of reducing drag on said fluid flow. 
   
   
       7 . A heat-transfer Venturi duct structure as in  claim 2 , wherein the cross-sectional area of said fin varies with distance from said Venturi wall. 
   
   
       8 . A heat-transfer Venturi duct structure as in  claim 1 , wherein the rate of heat transfer is controlled by variation of the pressure drop across said heat-transfer duct structure. 
   
   
       9 . A heat-transfer Venturi duct structure as in  claim 1  comprising a diffuser 
   
   
       10 . A heat-transfer Venturi duct structure as in  claim 9 , wherein said diffuser expands sufficiently slowly to maintain laminar flow. 
   
   
       11 . A heat-transfer Venturi duct structure as in  claim 1  wherein said duct exhausts flow into its local ambient environment. 
   
   
       12 . A Bernoulli heat-pump system comprising
 a heat source   a heat-transfer Venturi duct structure as in  claim 1     a thermal connection between said heat source and said thermally conducting section of said heat-transfer Venturi duct structure.   a working-fluid flowing in said heat-transfer duct structure   a blower mechanism that maintains said working-fluid flow through said duct structures   a duct structure connecting said heat-transfer Venturi duct structure to said blower mechanism   
   
   
       13 . A Bernoulli heat-pump system as in  claim 12  additionally comprising
 a heat sink   a heat exchange mechanism that transfers heat from said working-fluid flow to said heat sink   a duct structure connecting said blower mechanism to said heat-exchange mechanism   a duct structure connecting said heat exchange mechanism to the entrance of said heat-transfer Venturi duct structure   
   
   
       14 . A method for transferring heat to a flow comprising the steps of
 maintaining a pressure drop that maintains a flow of a fluid through a heat transfer Venturi duct structure, as described in  claim 1     maintaining a flow of heat into at least one thermally conducting cross-sectional portion of said heat-transfer Venturi duct structure heat-transfer slice.   
   
   
       15 . A method, as in  claim 14 , wherein
 the rate of heat transfer is controlled by variation of said pressure drop.