Heat exchanger

Abstract

This invention provides a heat exchanger ( 2 ) which has an elongate heat exchange element ( 4 ). The heat exchange element ( 4 ) has a substantially cylindrical structure with a first end and a second end and the length of the element ( 4 ) is greater than the diameter. A plurality of elongate flow paths extend between the first end and the second end. A first inlet ( 8 ) and a second outlet ( 14 ) are disposed in the first end and a first outlet ( 10 ) and a second inlet ( 12 ) are disposed in the second end. The first inlet ( 8 ) and first outlet ( 10 ) define a first flow path and the second inlet ( 12 ) and second outlet ( 14 ) define a second flow path. The heat exchanger is provided with a motor ( 16, 18 ) for rotating the cylindrical structure and the rotation of the cylindrical structure ( 4 ) moves the elongate flow paths from the first flow path to the second flow path.

1 . An airflow heat exchanger configured to exchange heat between an extract air flow and in inlet air flow of a building, the heat exchanger comprising:
 an elongate heat exchange element comprising:   a substantially cylindrical structure having a first end operably located on the inside of the building and a second end operably located on the outside of the building and wherein the length is greater than the diameter;   walls defining a plurality of elongate flow paths extending between the first end and the second end; and   a first inlet and a second outlet disposed in the first end and a first outlet and a second inlet disposed in the second end, the first inlet and first outlet defining a first flow path for drawing clean fresh air into the building and the second inlet and second outlet defining a second flow path for extracting air from the building;   and, means for rotating the cylindrical structure;   wherein rotation of the cylindrical structure moves the elongate flow paths from the first flow path to the second flow path to transfer heat absorbed by walls of the heat exchange element when in the second flow path to air passing through the first flow path;   a seal element that seals against the end faces of the plurality of elongate flow paths, the seal element defining the first flow path on one side thereof and the second flow path on the other side thereof, the seal element being divided into two sections arranged relative to one another such that a larger flow area is presented on one side of the seal than on the other side of the seal, the second flow path being directed through the larger flow area such that operably more heat can be imparted to the side walls of the flow passages by the extracted air.   
     
     
         2 . A heat exchanger according to  claim 1  wherein the plurality of elongate flow paths, which may be hexagonal in cross section, comprises one of: a plastics extrusion containing a plurality of parallel flow paths; and a plurality of elongate straw like elements arranged adjacent one another. 
     
     
         3 . A heat exchanger according to  claim 1  wherein the second flow path comprises a cooled air flow path and the first flow path comprises a heated air flow path and wherein the second flow path comprises a greater number of the plurality of elongate flow paths than the first flow path. 
     
     
         4 . A heat exchanger according  claim 1  wherein the seal element comprises two seals extending substantially from the centre of rotation of the cylindrical element to the edge of the cylindrical element; and/or wherein the seal comprises a plurality of resilient rollers arranged to rotate against the end faces of the plurality of flow paths as they rotate. 
     
     
         5 . A heat exchanger according to  claim 4  wherein the seal comprises a resilient core supporting a compliant low friction fabric rubbing surface. 
     
     
         6 . A heat exchanger according to  claim 1  comprising an inlet fan in fluid communication with the first flow path and an outlet fan in fluid communication with the second flow path, said first and second fans for driving gas through the first flow path in a first direction and a through the second flow path in the opposite direction to effect that transfer between the fluid flowing in the first and second flow paths. 
     
     
         7 . A heat exchanger according to  claim 6  wherein: the fans are either located at or adjacent the second end of the cylindrical structure; the fans are located at opposite ends of the cylindrical structure; or the fans are located at a common end of the cylindrical structure and are driven by a single motor. 
     
     
         8 . A heat exchanger according to  claim 1  wherein the seal element is surrounded by a seal housing and wherein the seal housing at the second end of the cylindrical structure further comprises a seal bypass within the housing so that, immediately adjacent the seal, a flow path is provided from outlets of the elongate flow paths of the first flow path to the inlets of the elongate flow paths of the second flow path. 
     
     
         9 . A heat exchanger according to  claim 8  further comprising an inlet fan in fluid communication with the first flow path and an outlet fan in fluid communication with the second flow path, said first and second fans for driving gas through the first flow path in a first direction and a through the second flow path in the opposite direction to effect that transfer between the fluid flowing in the first and second flow paths and wherein the fans are located at or adjacent the first end of the cylindrical structure. 
     
     
         10 . A heat exchanger according to  claim 1  wherein the cylindrical structure is mounted within a bearing at either end, and the means for rotating the cylindrical structure comprises a drive means configured to apply a force to the exterior of the cylinder so as to rotate it within the bearings.