Abstract:
The present invention relates to a method for manufacturing a heat exchanger, comprising steps of manufacturing plates for an upper side and an underside of the heat exchanger, arranging a profile comprising edges and ribs in at least one of the plates, which profile, after assembly of the heat exchanger, defines a space on the inside of the heat exchanger, which space has a zigzag form for allowing a fluid to flow therethrough, fixing the plates to each other along the ribs and edges.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application is a continuation-in-part of application Ser. No. 10/257,552 filed Dec.  10 ,  2002 , which is the United States national phase of International Application No. PCT/NL 01/00285 filed Apr. 10, 2001, which designated, inter alia, the United States, and which claims priority to Netherlands Application No. 1014893, filed Apr. 10, 2000. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     1) Field of the Invention  
         [0003]     The present invention relates to a method for manufacturing a heat exchanger, a solar collector, a storage container, a system comprising a solar collector and a method for manufacturing a storage container for a liquid.  
         [0004]     2) Description of the Prior Art  
         [0005]     As alternative to the use of fossil fuels, use is increasingly made of for instance solar energy. One application of solar energy is the storage of the energy in a liquid medium.  
         [0006]     Such systems are per se known, for instance from the publication of the international patent application of the same inventor as this application, WO 01/77590 Al. This document describes a flat plate collector. This collector already provides a relatively high efficiency; it is however relatively expensive to manufacture.  
       SUMMARY OF THE INVENTION  
       [0007]     In order to obviate the above stated drawback and provide an improved device for heat exchange, the present invention provides a method for manufacturing a heat exchanger, comprising steps for:  
         [0008]     manufacturing plates for an upper side and an underside of the heat exchanger,  
         [0009]     arranging a profile comprising edges and ribs in at least one of the plates, which profile, after assembly of the heat exchanger, defines a space on the inside of the heat exchanger, which space has a zigzag form for allowing a fluid to flow therethrough;  
         [0010]     fixing the plates to each other along the edges and ribs.  
         [0011]     An advantage of an embodiment according to the present invention is that the space allowing the fluid to flow through can be realized relatively advantageously by means of arranging the profile in at least one of the plates.  
         [0012]     According to an embodiment, the profile is arranged in the plate by means of deep-drawing. A profile in a plate can hereby be arranged in a plate in one operation. It is further possible to arrange the profile by means of a roller on which the desired profile is arranged on the surface.  
         [0013]     The plates preferably comprise stainless steel or another durable metal. The use of stainless steel is highly feasible in such a heat exchanger since there is direct contact between the fluid medium and the metal, whereby a very high efficiency can be achieved despite the slightly lower conduction compared to for instance copper.  
         [0014]     For fixing purposes the plates are preferably welded to each other. It is also advantageous if the plates are provided with a coating for increasing the absorption capacity of the surface and optionally reducing the emission capacity at operational temperatures.  
         [0015]     The above stated method preferably also comprises steps for arranging at least one turbulence member in at least one of the plates for the purpose of causing turbulence in the flow of the fluid. This turbulence assists in spreading the collected heat through the whole fluid volume. It is known of for instance water that the heat conduction is relatively low.  
         [0016]     A further aspect of the present invention relates to a solar collector, comprising:  
         [0017]     a first plate for collecting solar energy,  
         [0018]     a second plate which is fixed at least substantially along the edges on the underside of the first plate,  
         [0019]     a space between the two plates,  
         [0020]     an inlet for feeding a liquid to the space,  
         [0021]     an outlet for discharging the liquid from the space of zigzag form, whereby the liquid can flow from the inlet to the outlet, wherein  
         [0022]     the space between the plates is formed in that a profile defining the zigzag form of the space is arranged in at least one of the plates.  
         [0023]     Such a collector has advantages as described in the foregoing. The manufacture thereof is relatively advantageous because a profile is arranged in the metal plate, which profile forms the space for the liquid serving as heat transfer medium. The profile is preferably manufactured by means of deep-drawing or for instance rolling.  
         [0024]     In a further embodiment the solar collector comprises turbulence members for causing turbulence in the liquid in the space. An optimal heat distribution is hereby realized in the liquid when the liquid is driven through the zigzag channels. These turbulence members for instance comprise oblique ribs which narrow the throughflow channel by 50 to 90 percent as seen in the direction of flow.  
         [0025]     In a further preferred embodiment, the solar collector comprises a housing for placing of the plate assembly, comprising:  
         [0026]     a lower wall, comprising a plastic and a framework for supporting the plate assembly and a cover plate, formed integrally,  
         [0027]     an insulation layer which is arranged on the lower wall inside a framework for supporting the plate assembly,  
         [0028]     a cover plate being permeable to radiation and having insulating properties. An advantage of this embodiment is that a maximum efficiency of the solar collector can be realized with a minimum number of components. In addition, this collector can be placed in simple manner at the location where it has to function. Such a solar collector is further simple to assemble and relatively easy to handle and transport in the assembled form.  
         [0029]     The solar collector as specified above preferably comprises a mounting profile extending round the periphery of the plate assembly. An advantage of such a profile is that the perhaps slightly rough edge of the plate assembly is shielded relative to the framework within which the plate assembly is placed. With a suitable choice of material such a profile also functions as member for damping vibrations and/or sounds produced by the liquid flow in the plate assembly.  
         [0030]     A further aspect of the present invention relates to a storage container for a liquid, comprising:  
         [0031]     an inner wall and an outer wall, each comprising a bottom wall for the storage container, which are moulded from a plastic,  
         [0032]     a closing cover for closing the container which is also double-walled and filled with a foaming insulating means,  
         [0033]     a number of passage openings for passage of at least supply and discharge conduits for the liquid,  
         [0034]     a number of passage openings for passage of at least a supply and a discharge for a heat exchanger, and  
         [0035]     an insulating means such as PUR foam which fills the space between the inner wall and the outer wall by foaming during or after introduction thereof between the inner wall and the outer wall.  
         [0036]     An advantage of such an embodiment is that a storage container can be manufactured in relatively simple manner. The storage container is here very light, durable and insulates well. This is an open vessel whereby the whole collector system can be given a pressure-less form.  
         [0037]     A per se known, preferably spiral-shaped heat exchanger is preferably arranged in the container. Hot water, for instance tap water or heating water, stored in the container is carried through this heat exchanger. Further openings which can be arranged in the storage container serve for instance for a probe or for an overflow.  
         [0038]     The inner wall and the outer wall are preferably molded integrally from a plastic. A technique such as rotation molding is for instance applied for this purpose.  
         [0039]     For insulation purposes the closing cover preferably encloses a part of the wall of the container in vertical direction in the position of use.  
         [0040]     A further aspect of the present invention relates to a solar collector as specified in the foregoing which is manufactured using a method as specified in the foregoing and to a storage container as specified in the foregoing, and:  
         [0041]     conduits for transporting a liquid from the storage container to the collector and vice versa,  
         [0042]     a pump for driving liquid through the conduits. Advantages of such a system are similar to the advantages described in the foregoing.  
         [0043]     A further aspect of the present invention relates to a method for manufacturing a storage container for a liquid, comprising steps for:  
         [0044]     introducing a liquid curable plastic into a mould defining an outer wall, an inner wall and a connection therebetween,  
         [0045]     rotating the mould such that the plastic is distributed over the whole surface of the mould,  
         [0046]     curing the plastic,  
         [0047]     arranging a foaming, heat-insulating plastic in the space between the inner wall and outer wall, wherein the plastic fills the whole space between the inner wall and the outer wall. An advantage of such a method is that a very effectively insulating storage container can be obtained in relatively simple and favorable manner. Such storage containers can be applied in situations where an insulating action is desired. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0048]     Further advantages, features and details of the present invention will be further described on the basis of a number of embodiments, which will be described with reference to the accompanying figures, in which:  
         [0049]      FIG. 1  is a top view of a first embodiment according to the present invention;  
         [0050]      FIGS. 2, 3 ,  4  and  9  show cross sections of the embodiment of  FIG. 1 ;  
         [0051]      FIG. 5  is an exploded view in perspective of a further embodiment comprising the embodiment of  FIG. 1 ;  
         [0052]      FIG. 6  is a cross-sectional view of a detail of  FIG. 4 ;  
         [0053]      FIG. 7  is a cross-sectional view of a detail of  FIG. 4 ;  
         [0054]      FIG. 8  is a cross-sectional view of a detail of  FIG. 9 ;  
         [0055]      FIG. 10  is a top view of a further embodiment according to the present invention;  
         [0056]      FIG. 11  is a perspective view of a detail of  FIG. 10 ; and  
         [0057]      FIG. 12  shows a cross section and partial side view of a further embodiment according to the present invention. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0058]     A first embodiment ( FIG. 10 ) is a flat plate collector  1 . This is shown from the top in  FIG. 10 . In this embodiment the lower plate (not shown) is flat. A profile of channels and turbulence ribs  11 ,  13  is arranged in the upper plate. The channels are formed by edges  7 ,  8 ,  9 ,  10  in addition to channel ribs  3 ,  5 . A heat medium such as water flows through the channels designed in a zigzag form. The water enters the collector on the one side at inlet  2  and exits at outlet  4  on the other side of the collector.  
         [0059]     The lower corner close to water inlet  2  is shown in perspective in greater detail in  FIG. 11 . The flat plate collector  1  comprises a lower plate  16 , which in this embodiment takes a flat form, and an upper plate  17  in which a profile is arranged by means of deep drawing. In an alternative embodiment both plates are provided with a profile. The two plates are welded to each other along the broken lines  88 , for instance by means of laser welding. Situated between the two plates is a space through which the heat transport medium water flows from inlet  2  to outlet  4 . The channels are formed by the channel ribs  3  which are bounded by channel walls  86  and  87 . The collector is bounded on the side by wall  85 .  
         [0060]     In order to improve the heat transfer from upper plate  17  to the water, swirling ribs or turbulence ribs  11 , 13  are arranged in the upper plate. These extend at an angle from one side of the channel to the other side of the channel. Turbulence rib  11  is formed by two walls  81  and  82  lying in a V-shape relative to one another. Turbulence rib  13  is formed by two walls  83  and  84  lying in a V-shape relative to one another. Turbulence ribs  11  and  13  partly close the throughflow channel in vertical direction, whereby turbulence occurs in the flowing water. Turbulence likewise occurs due to the angle at which the turbulence ribs are arranged in the channels. The height of the ribs and the angle thereof can be varied depending on the use of the collector. More or fewer ribs can likewise be arranged per channel. The upper side of collector plate  17  can be further provided with a suitable coating to bring about better absorption of the solar radiation. Depending on the amount of solar radiation and ambient temperature at-the location of use of the collector, an optimal coating can be applied which for instance optimizes the ratio of the absorption properties and the radiation emission properties.  
         [0061]     Plates  16 ,  17  of stainless steel are particularly suitable for the application in this embodiment. Such a metal provides a very long lifespan and is relatively advantageous. It is also possible to suffice with relatively thin plate material, such as for instance between 0.1 and 1 millimeter. A consequence hereof is that solar collectors can be manufactured with a low weight of between 10 and 20 kilograms per m 2. A further advantage of the construction of this embodiment is that, when water is used as heat medium, the addition of antifreeze is not necessary.  
         [0062]      FIG. 5  shows in cut-away perspective view an assembly of a mounting plate  50 , insulating material  51 , collector  1 , mounting profile  52  and cover plate  53 . Mounting plate  50  is manufactured from a plastic, for instance by means of injection molding from for instance polyethylene. This plate has a relatively complex profile with a number of advantages. These will be further elucidated herein below with reference to  FIGS. 2-9 .  
         [0063]     Cover plate  53  is preferably manufactured from Perspex. This material has the advantage that it has electrostatic properties, is dirt-repellent and can be cleaned in simple manner by means of water. For fixing purposes the plate is provided with clamping protrusions  54 . These are clamped round a bulge ( FIG. 8 ) of an edge of the mounting plate ( FIG. 8 ). Alternatively, a (hardened) sheet of glass can be used as cover plate.  
         [0064]     Arranged directly onto mounting plate  50  is an insulating plate  51 . This latter is situated immediately or some distance below collector  1 . Collector  1  is held in position under cover plate  53  by means of a mounting strip. In an embodiment (not shown) there is present in mounting strip  52  a groove in which the edge of collector  1  can be placed. In the shown embodiment the collector is placed on the insulation layer, where after the mounting strip is placed on the edge of the collector.  
         [0065]     The embodiment of mounting plate  50  is particularly suited for placing on inclining roofs instead of the roof tiles that are present. A recess  28  is provided for this purpose on the underside for supporting on a so-called tiling batten.  
         [0066]     Situated on either side of mounting plate  50  are two edges  26 ,  27  for guiding rainwater. This prevents rainwater flowing away to the sides. On the upper side of mounting plate  50 , at least as seen in the mounting position, there is situated a mounting strip or mounting elevation  25 .  
         [0067]     In the view of  FIG. 1  there are indicated a number of sections which are shown in cross section in the respective  FIGS. 2, 3 ,  4 ,  9 .  
         [0068]      FIG. 1  further shows strengthening ribs  21  and  22  which are situated in the central area of mounting plate  50 . Indicated close to the edges of mounting plate  50  are profile edges  31 ,  32 ,  33 ,  34  which will be shown in detail in the cross-sectional views. Collector plate supports  24  are located on the inner side of the corners of profile edges  31 ,  32 ,  33 ,  34 .  
         [0069]      FIG. 2  shows the section II-II of  FIG. 1  in greater detail. It can be seen that insulating plate  51  is situated between the bottom of mounting plate  50  and collector  1 .  
         [0070]      FIG. 3  shows the section III-III of  FIG. 1  in greater detail. The section VIII of profile edge  32  is shown in greater detail in  FIG. 8 . Further shown in the view of  FIG. 3  is profile edge  34  and the insulating plate on mounting plate  50  on which collector  1  is situated. Situated there above is cover plate  53 . Mounting profile  52  is situated along profile edges  32  and  34  between the collector and the cover plate for the purpose of holding the collector plate positioned under and some distance from cover plate  53 .  
         [0071]     In addition to the components shown in  FIGS. 2 and 3 , a further cross section of the assembly is shown in  FIG. 4  along the cross-sectional line IV-IV of  FIG. 1 . The cross section of profile edge  33  and the tiling batten support situated adjacently thereof is shown in greater detail in  FIG. 6 . Profile edge  31  and the mounting strip situated adjacently thereof are shown in greater detail in  FIG. 7 .  
         [0072]      FIG. 9  shows profile edge  32 , which is shown in greater detail in  FIG. 8 . This profile edge  32  comprises at that position a snap protrusion for snap fixing of the cover plate. Profile edge  34  likewise comprises snap protrusions.  
         [0073]      FIG. 6  shows a cross section of profile edge  33  in detail. This is located on the underside in the position of assembly of the collector. Profile edge  33  is formed by a wall  61  which runs upward from the bottom of mounting plate  50  and which transposes into the horizontally running wall  62 , which then extends in downward direction by means of downward wall  63 . On the underside of this downward wall  63  there extends a laterally running wall part  64  which serves as support on a tiling batten. As shown in  FIG. 1 , this tiling batten support  64  extends over the whole width of mounting plate  50 . It hereby becomes possible to place this tiling batten support on a tiling batten which extends to both sides.  
         [0074]      FIG. 7  shows in cross section the upper side of the mounting plate as seen in the position of assembly. Mounting plate  50  extends upward from the bottom thereof by means of wall  71  which transposes into horizontal wall  72  and extends downward therefrom by means of wall  73 . From the underside of wall  73  the mounting plate extends by means of horizontal wall  74  which comprises mounting edge  25 .  
         [0075]      FIG. 8  shows in cross section mounting profile  32  of mounting plate  50  at the position of line IX-IX of  FIG. 1 , this detail also being indicated with VIII in  FIG. 9 . Mounting plate  50  extends from the bottom thereof in upward direction by means of wall  81 . This wall  81  transposes into horizontal upper wall  82  which then extends into arcuate wall  83  which forms the snap protrusion for fixing cover plate  53 . This arcuate part  83  transposes into vertical part  84  of profile  32 . Via several undulations the wall continues in downward direction to vertical part  85 . From vertical wall part  85  the mounting plate extends laterally by means of side flap  28 . This side flap  28  is provided with water barriers  26 ,  27 . These water barriers  26 ,  27  serve to prevent water flowing out to the sides. In an alternative embodiment, the cover plate is fixed by means of for instance expanding rivets, rivets, bolts or other suitable means known to the skilled person. The expanding rivets have the advantage that they can be rapidly placed.  
         [0076]      FIG. 8  further shows clearly the relative positioning of insulation  51 , plate assembly  1  and mounting strip  52  under cover plate  53 .  
         [0077]      FIG. 12  shows a further embodiment according to the present invention. A storage container  111  serves for the storage of water or other appropriate liquid heated by means of the collector plate. Storage container  11  comprises a double-walled, bucket-like vessel and a cover fitting thereon. The vessel is formed by inner wall  113  and outer wall  112 , inner bottom  116  and outer bottom  115  and upper wall  114 . Such a vessel is manufactured in particularly advantageous manner from a piece of plastic, for instance by means of rotation molding. By means of an opening (not shown) suitable for the purpose, preferably in outer bottom  115 , a foaming insulation material is then introduced which fills the whole space  120  with foam during or after introduction. The cover is manufactured in similar manner. The cover comprises upper wall  127 , lower wall  125  and side wall  129 . These walls enclose the insulated inner space  126 . A very well insulating foaming plastic is preferably also arranged in this inner space. For a good connection onto the vessel, the cover is provided with annular grooves  130  into which the upper part of the hollow wall of the vessel fits. The groove between the vessel and the cover can be further sealed by means of suitable insulating material. One or more annular elements can for instance be applied for this purpose. The water from the solar collector is carried into the storage container by means of a conduit  122 , which in this embodiment runs through the cover. The cold water is fed in the direction of the collector by means of conduit  121  which draws off the colder water on the underside of the collector vessel. This conduit  121  is preferably insulated in order to isolate the cold water, during transport thereof to the top of the vessel, from the relatively warm water present there. A heat exchanger  126  is also situated in the vessel. This heat exchanger preferably extends in the relatively warm part of the collector vessel water. This for instance spiral-shaped heat exchanger is connected to the outside world by means of conduits  123  and  124  which in this embodiment run through the cover of the storage container.  
         [0078]     The present invention is described on the basis of several embodiments, the different aspects of which can be readily varied by the skilled person within the concept of the present invention. The rights sought are defined by the appended claims.