COOLER

Abstract

A cooler, having individual cooling elements (1) of stacked construction having ducts (25) extending in parallel to one another, each of which delimits a flow chamber (29) for the throughflow of a liquid medium to be cooled, between which at least two layers (3, 5) of individual rows of meandering fins (34) extend, which for the throughflow of air jointly delimit a further flow chamber (26, 28) each, is characterized in that the respective one flow chamber (29), free of obstacles, permits a laminar flow of the liquid medium through the assignable duct (25) in one throughflow direction, in that the height (H1) of each fin (34), viewed transversely to the direction of throughflow of the liquid medium, has at least the same height as the free throughflow cross section of the flow chamber (29) of the adjacently arranged duct (25), viewed in parallel to the extension of the respective fin (34), and in that in every layer (3, 5), a plurality of rows (36) of several fins (34) are arranged in succession, which each viewed in the direction of throughflow of the duct (25) are offset from each other.

Claims

1. A cooler, having individual cooling elements (1) of stacked construction having ducts (25) extending in parallel to one another, each of which delimits a flow chamber (29) for the throughflow of a liquid medium to be cooled, between which at least two layers (3, 5) of individual rows (36) of meandering fins (34) extend, which for the throughflow of air jointly delimit a further flow chamber (26, 28) each, characterized in that the respective one flow chamber (29), free of obstacles, permits a laminar flow of the liquid medium through the assignable duct (25) in one throughflow direction, in that the height (H1) of each fin (34), viewed transversely to the direction of throughflow of the liquid medium, has at least the same height (H2) as the free throughflow cross section of the flow chamber (29) of the adjacently arranged duct (25), viewed in parallel to the extension of the respective fin (34), and in that in every layer (3, 5), a plurality of rows (36) of several fins (34) are arranged in succession, which each viewed in the direction of throughflow of the duct (25) are offset (P) from each other.

2. The cooler according to claim 1, characterized in that at least part of the fins (34) of each layer (3, 5) adjoining one another extends in a bar-like manner each, forming a waveform between two respective opposite deflection points (38), and in that deflection points (38) of two adjacent layers (3, 5) are congruently facing each other in a joint plane (E) adjoining the adjacently arranged ducts (25) of a cooling element (1).

3. The cooler according to claim 1, characterized in that in the respective plane (E) a partition wall (27) extends in parallel to the throughflow direction of the liquid medium in the ducts (25).

4. The cooler according to claim 1, characterized in that the respective partition wall (27) has the same material thickness as the fins (34) forming the waveform.

5. The cooler according to claim 1, characterized in that the height (H1) of a single bar-like fin (34) is preferably three to six times, and particularly preferably five times, the height (H2) of the flow chamber (29) for a duct (25).

6. The cooler according to claim 1, characterized in that the flow chamber (29) of every duct (25) has a free opening cross-section, which is solely delimited in a rectangular shape by peripheral duct walls (23, 23′, 24), whose material thickness preferably matches the wall thickness of the respective fin (34).

7. The cooler according to claim 1, characterized in that the offset (P) is selected in such a way that the respective fin (34) of a further fin row (36), arranged between two to each other parallel, offset-free fin rows (36), extends offset from the adjacent fins (34) of the two adjacent fin rows (36) by a predeterminable axial distance, in parallel to the respective duct (25), viewed in its flow direction.

8. The cooler according to claim 1, characterized in that the offset (P) is 3 mm to 8 mm, preferably 4 mm to 6 mm, particularly preferably between 5 mm to 5.9 mm.

9. The cooler according to claim 1, characterized in that the height (H1) of a single fin (34), viewed transversely to the direction of flow through a duct (25), is between 5 mm to 15 mm, preferably 12 mm, and in that the total depth of every cooler element (1), having a plurality of fin rows (36) arranged in succession, is 60 mm to 90 mm, preferably 63 mm and 82 mm, in depth.

10. The cooler according to claim 1, characterized in that the wall thickness of the fins (34), formed from a sheet material, is 0.15 mm to 0.4 mm, preferably 0.2 mm, and the wall thickness of a panel, consisting of sheet material, as a partition wall (27) between the fin rows (36) is 0.2 mm to 0.8 mm, preferably 0.4 mm.

11. The cooler according to claim 1, characterized in that the meander shape of the respective fin row (36) has bar-like fins (34), extending in parallel to one another, and in that two adjacent fins (34) of the fin rows (36) are each integrally interconnected via the deflection points (38) in the form of connecting bars, which extend in parallel to the ducts (25) having the boundary walls (24), in their direction of flow.

12. The cooler according to claim 1, characterized in that the fin rows (36) and the ducts (25) extend between two media-conveying main struts (20) forming the fluid connections with the ducts (25) and span a rectangular front face (16) as cooler surface, and that 20 to 48, preferably 25 to 63, particularly preferably 54 ducts (25) form the effective cooler surface.

13. A wind turbine, in which at least one cooler according to claim 1 is spatially assigned to a nacelle (4) of the turbine, for the purpose of flow through the flow chambers (26, 28) without any fan drive only based on the blade air flow and/or purely wind-driven ambient air.

Description

[0023] The invention is explained in detail below, with reference to an exemplary embodiment shown in the drawing. In the Figures:

[0024] FIG. 1 shows a highly schematically simplified and cut off perspective oblique view of the end region, adjacent to the nacelle, of a wind turbine provided with two coolers according to the invention;

[0025] FIG. 2 shows a perspective oblique view of the exemplary embodiment of the cooler according to the invention;

[0026] FIGS. 3 and 4 show a front view and a top view, respectively, of the exemplary embodiment of the cooler;

[0027] FIG. 5 shows an illustration, drawn at approximately twice the magnification of a practical embodiment, of the partial area, designated by V in FIG. 3, of the exemplary embodiment;

[0028] FIG. 6 shows a front view of a section of two rows of fins succeeding each other in the direction of air flow;

[0029] FIGS. 7 and 8 show perspective oblique view and top view, respectively, of three rows of fins succeeding each other in the direction of air flow; and

[0030] FIG. 9 shows a perspective front view on a part of a duct, not connected to a main strut, for the medium to be cooled, wherein the wall thicknesses are shown larger for better illustration.

[0031] FIG. 1 shows only the nacelle 4 of a wind turbine 2 in a highly simplified form, wherein said nacelle 4 is rotatably arranged on a tower 6 only suggestively shown. Only a hub 10 together with blade roots 12 of rotor blades, otherwise not shown, of a rotor, located at the front 8 of nacelle 4, are shown. Two coolers 18, according to the exemplary embodiment of the invention, are arranged adjacent to each other on the upper side 14 of the nacelle 4 in such a way that their front faces 16 are exposed in the direction of the wind flow flowing along the nacelle surface 14. Further details of the cooler 18 can be taken from FIGS. 2 to 9.

[0032] As shown in FIGS. 2 and 3, the front face 16, exposed to the wind flow, of the cooler 18 is square in outline. On both sides, main struts 20, forming a support structure, adjoin the front face 16, wherein each of said main struts 20 is shaped like a bar-like hollow box having an arbitrarily shaped cross-section, which in the exemplary embodiment shown is square, and each main strut 20 forms a collecting chamber for the liquid medium to be cooled. This can be a water-glycol mixture that is heated by the lost heat generated in the operation of the wind turbine, wherein said lost heat is to be dissipated to the ambient air. Ports 22 for the inflow and outflow of the medium are arranged on the struts 20, which form a medium passage to the interior of the respective collecting chamber. While FIGS. 2 to 4 show the ports at the upper ends of the struts 20, it goes without saying that the ports 22 are conveniently provided on the underside, facing the nacelle top 14, if the coolers 18 are attached to the top 14 of the nacelle 4.

[0033] In the exemplary embodiment shown in the drawing, the lateral length of the square outline and thus the depth of the radiator measured perpendicular to the plane of the end face 16 is 63 mm. The height of the struts 20 measured in the drawing plane of FIG. 3 and the spacing of the struts 20 are such that the front faces 16 span a rectangular front face 16, exposed to the ambient wind, as a cooler surface. Boundary walls 24 extend between the struts 20, only part of which boundary walls are numbered in FIGS. 2 and 3 and which are formed from thin, flat-surfaced aluminum plates, whose width matches the lateral length of the square outline of the struts 20, see FIG. 4. The boundary walls 24 are, see FIGS. 5 and 9, each combined into groups of two, in which the walls 24 extend equidistantly from each other and in parallel and, with a front wall 23 and a rear wall 23′ in between them, form a duct 25 for the medium to be cooled, in particular in the form of a liquid. The groups of two of the boundary walls 24, extending equidistantly from each other and in parallel, each delimit between them a combination of two flow chambers 26 and 28, separated by a further panel used as a partition wall (27), wherein through said flow chambers 26 and 28 the ambient air can flow from the front face 16 forming the cooling surface. The ends of the ducts 25, formed between the boundary walls 24, are each connected to the collecting chamber inside the struts 20 in a fluid conveying manner and, in operation, the liquid medium to be cooled flows therethrough. In this example, the width of the ducts 25, measured transversely to the longitudinal direction of the duct, is 3 mm each.

[0034] The cooler 18 shown in the figures is formed of individual cooling elements 1 in a stacked structure with the ducts 25 extending in parallel to each other. In any case, any single cooling element 1 has a combination of two layers 3, 5 of meandering fins 34, wherein the two layers 3, 5 of a cooling element 1 are separated by the partition wall 27, which extends in a horizontal plane E.

[0035] As shown in particular in FIG. 9, each individual duct 25 of rectangular, in particular square, cross-section is delimited by the walls 24 at the top and at the bottom and by a front wall 23 and a rear wall 23′. In this respect, the duct 25 mentioned spans a kind of flow chamber 29, which, kept free of obstacles, permits a laminar flow of the liquid medium to be cooled through the duct 25 in a flow direction.

[0036] The vertical height H1 of every fin 34, viewed transversely to the flow direction of the liquid medium, has at least the same height H2 as the free flow cross-section of the flow chamber 29 of the adjacently arranged duct 25, viewed in parallel to the extension of the respective fin 34 in its heightwise orientation. In every layer 3, 5, there is in turn a plurality of rows 36 of a plurality of fins 34, which are arranged in succession in the horizontal direction (see FIGS. 7 and 8), and each has an offset P (see FIG. 6) from one another, viewed in the direction of flow through the duct 25. This axial offset P of the rows 36 arranged in succession is viewed in the horizontal direction towards the front face of the cooler 18.

[0037] As can be taken from FIGS. 5 to 9, for transferring the heat of the liquid medium flowing through the ducts 25 to the air flowing through the flow chambers 26 and 28 fins 34, whose surfaces are flowed against by the cooling air flowing therethrough, are located in the flow chambers 26, 28. As is most clearly shown in FIGS. 7 and 8, the fins 34, which are only partially numbered in the figures, are arranged in the fin rows 36, wherein the rows 36 extend in a direction in parallel to the plane of the front face 16 and the rows 36 are arranged in succession viewed in the direction of flow. The identically formed fins 34 are each formed by sheet metal parts made of aluminum sheet having a rectangular outline, wherein the sheet thickness in this exemplary embodiment is 0.2 mm. The fins 34 extend in a direction in parallel to the direction of the air flow and perpendicular to the longitudinal direction of the ducts 25 and have a height H1, which matches the height of the assigned flow chamber 26 or 28. In this example, the height of the flow chambers 26 and 28 and accordingly the height H1 of the fins 34 is 10.3 mm. At the ends adjacent to the boundary walls 24, the fins 34 are interconnected by connecting bars (also not all numbered in the figures), forming deflection points 38 and continuing in one piece the sheet material, wherein the connecting bars lie against the facing boundary wall 24 in a planar manner and are secured thereto by bonding or welding. Owing to the planar contact of the deflection points 38, every fin 34 is in close heat-conducting contact with a duct 25. This also applies to the articulation of the fins 34 to the panel spanning a partition wall 27, wherein said panel extends in the horizontal direction.

[0038] As shown in FIGS. 7 and 8, the rows 36 of fins 34 with the flow chambers 26 are arranged in succession without distance in the direction of the air flow, wherein successive rows 36 each are displaced alternately to one side and the other side in the longitudinal direction of the ducts 25 by half the width of the connecting bars or deflection points 38 and thus, as viewed in their direction of flow, axially. As indicated by the dashed line 40 in FIG. 8, the flow division forms zigzag flow paths for the air flow through the flow chambers 26. The width of the fins 34, measured in the direction of flow, or their depth in this example matches the height H1 of the fins 34, wherein the number of fin rows 36, measured in the direction of flow, is selected such that the depth of this exemplary embodiment of the cooler is 63 mm. The width of the connecting bars 38, measured in the longitudinal direction of the ducts 29, is selected such that the offset of the fins 34, denoted by P in FIG. 6, is 5 mm in this exemplary embodiment.

[0039] The arrangement of the fin rows 36, provided in the invention, and their geometric form having contact surfaces, formed via the connecting bars 38, as deflection points on the boundary walls 24 permits a particularly effective heat coupling for heat transfer from the heated medium in the ducts 25 to the fins 34, which have large surfaces against which air flows. In addition, because the fin rows 36 of each flow chamber exchange heat with both air-conveying ducts 26 and ducts 28, the coolers according to the invention provide a cooling capacity, which renders the use of the coolers 18 for the dissipation of the heat loss occurring during operation without supporting, motor-driven auxiliary fans possible, while the mounting area on the nacelle 4 of a wind turbine can be freely selected. This is without parallel in the prior art.