Heat exchangers and tower structure for density-driven power generation

Abstract

A power-generating tower comprises: at least one of the lower heat-exchange assemblies, at least one of the upper heat-exchange assemblies, a tower structure arranged to support each upper heat-exchange assembly, at least one ascending circulating-fluid column within the tower structure, at least one descending circulating-fluid column within the tower structure, and at least one turbine. Each ascending column is arranged and connected to receive the circulating fluid from at least one of the lower heat-exchange assemblies and to convey the circulating fluid thus received upward and into at least one of the upper heat-exchange assemblies. Each descending column is arranged and connected to receive the circulating fluid from at least one of the upper heat-exchange assemblies and to convey the circulating fluid thus received downward and into at least one of the lower heat-exchange assemblies. The turbine is arranged to be driven by flow of circulating fluid.

1 . (canceled) 
     
     
         2 . (canceled) 
     
     
         3 . An apparatus comprising:
 at least one lower heat-exchange assembly;   at least one upper heat-exchange assembly;   a tower structure arranged to support each upper heat-exchange assembly at an elevation higher than that of the lower heat-exchange assembly;   at least one ascending circulating-fluid column within the tower structure;   at least one descending circulating-fluid column within the tower structure;   at least one buoyant cell; and   at least one turbine,   wherein each ascending column is arranged and connected to receive the circulating fluid from at least one of the lower heat-exchange assemblies and to convey the circulating fluid thus received upward and into at least one of the upper heat-exchange assemblies,   wherein each descending column is arranged and connected to receive the circulating fluid from at least one of the upper heat-exchange assemblies and to convey the circulating fluid thus received downward and into at least one of the lower heat-exchange assemblies,   wherein the buoyant cell is filled with a lighter-than-air gas and is arranged to support at least a portion of the weight of the upper heat-exchange assembly or is arranged within the tower structure to support a portion of its weight; and   wherein the turbine is arranged to be driven by flow of circulating fluid.   
     
     
         4 . A method for using the apparatus of  claim 3 , the method comprising:
 (i) transferring heat from lower ambient fluid to the circulating fluid in the at least one lower heat-exchange assembly;   (ii) conveying the circulating fluid from each lower heat-exchange assembly upward through the at least one ascending column in the tower structure to the at least one upper heat-exchange assembly;   (iii) transferring heat from the circulating fluid to upper ambient fluid in each upper heat-exchange assembly;   (iv) conveying the circulating fluid from each upper heat-exchange assembly downward through the at least one descending column in the tower structure; and   (v) driving the at least one turbine with flow of the circulating fluid.   
     
     
         5 . A method comprising:
 (i) during daylight, transferring heat from lower ambient fluid to a circulating fluid in at least one lower heat-exchange assembly;   (ii) conveying the circulating fluid from each lower heat-exchange assembly upward through at least one ascending column to at least one upper heat-exchange assembly positioned at an elevation higher than that of the lower heat-exchange assembly;   (iii) during nighttime, transferring heat from the circulating fluid to upper ambient fluid in each upper heat-exchange assembly;   (iv) conveying the circulating fluid from each upper heat-exchange assembly downward through at least one descending column in the tower structure; and   (v) driving at least one turbine with flow of the circulating fluid,   wherein each ascending column is arranged and connected to receive the circulating fluid from at least one of the lower heat-exchange assemblies and to convey the circulating fluid thus received upward and into at least one of the upper heat-exchange assemblies,   wherein each descending column is arranged and connected to receive the circulating fluid from at least one of the upper heat-exchange assemblies and to convey the circulating fluid thus received downward and into at least one of the lower heat-exchange assemblies, and   wherein the turbine is arranged to be driven by flow of circulating fluid.   
     
     
         6 . A method comprising:
 (i) transferring heat from lower ambient fluid a circulating fluid in at least one lower heat-exchange assembly to boil the circulating fluid;   (ii) conveying the circulating fluid from each lower heat-exchange assembly upward through at least one ascending column to at least one upper heat-exchange assembly positioned at an elevation higher than that of the lower heat-exchange assembly;   (iii) condensing at least about 0.5% of the circulating fluid as it is conveyed through the ascending column;   (iv) transferring heat from the circulating fluid to upper ambient fluid in each upper heat-exchange assembly to condense the circulating fluid;   (v) conveying the circulating fluid from each upper heat-exchange assembly downward through at least one descending column in the tower structure; and   (vi) driving at least one turbine with flow of the circulating fluid,   wherein each ascending column is arranged and connected to receive the circulating fluid from at least one of the lower heat-exchange assemblies and to convey the circulating fluid thus received upward and into at least one of the upper heat-exchange assemblies,   wherein each descending column is arranged and connected to receive the circulating fluid from at least one of the upper heat-exchange assemblies and to convey the circulating fluid thus received downward and into at least one of the lower heat-exchange assemblies, and   wherein the turbine is arranged to be driven by flow of circulating fluid.   
     
     
         7 . A heat-exchange assembly comprising multiple heat-exchanging subunits wherein:
 (a) each of the heat-exchanging subunits comprises (i) an ambient-fluid passage, (ii) at least one circulating-fluid inlet, (iii) at least one circulating-fluid outlet, and (iv) multiple heat-exchange tubes, each of the multiple heat-exchange tubes connecting at least one inlet to at least one outlet so as to convey circulating fluid from the connected inlet through the heat-exchange tube to the connected outlet;   (b) in each of the multiple heat-exchanging subunits, the multiple heat-exchange tubes are arranged at least partly within the ambient-fluid passage so as to enable heat transfer between circulating fluid conveyed through the heat-exchange tubes and ambient fluid flowing through the ambient-fluid passage;   (c) the multiple heat-exchanging subunits are arranged in at least one substantially horizontal row or ring so as to direct flow of the ambient fluid through the ambient-fluid passages of the multiple subunits; and   (d) each row or ring of multiple heat-exchanging subunits is arranged within the ambient fluid so that a temperature-induced density differential of the ambient fluid, which density differential arises from the heat transfer, drives the flow of the ambient fluid through the ambient-fluid passages.   
     
     
         8 . A method for using the apparatus of  claim 7 , the method comprising:
 (i) supplying the circulating fluid to the corresponding circulating-fluid inlets of the multiple heat-exchanging subunits of the heat-exchange assembly; and   (ii) receiving the circulating fluid from the corresponding circulating-fluid outlets of the multiple heat-exchanging subunits of the heat-exchange assembly.   
     
     
         9 . A heat-exchange assembly comprising:
 (a) an ambient-fluid passage;   (b) at least one circulating-fluid inlet;   (c) at least one circulating-fluid outlet; and   (d) multiple heat-exchange tubes, each of the multiple heat-exchange tubes connecting at least one inlet to at least one outlet so as to convey circulating fluid from the connected inlet through the heat-exchange tube to the connected outlet,   wherein:   (e) the multiple heat-exchange tubes are arranged at least partly within the ambient-fluid passage so as to enable heat transfer between circulating fluid conveyed through the heat-exchange tubes and ambient fluid flowing through the ambient-fluid passage;   (f) the ambient-fluid passage is arranged so as to direct flow therethrough of the ambient fluid in a non-horizontal direction;   (g) the heat-exchange assembly is arranged so as to drive the flow of the ambient fluid through the ambient-fluid passage by a temperature-induced density differential, which density differential arises from the heat transfer, between the flowing ambient fluid at opposing ends of the ambient-fluid passage; and   (h) the heat-exchange assembly is immersed in the ambient fluid, which ambient fluid comprises atmospheric air.   
     
     
         10 . A method for using the apparatus of  claim 9 , the method comprising:
 (i) supplying the circulating fluid to the corresponding circulating-fluid inlets of the heat-exchange assembly; and   (ii) receiving the circulating fluid from the corresponding circulating-fluid outlets of the heat-exchange assembly.