DE202008001611U1 - Apparatus for solar energy production, in particular a solar collector - Google Patents

Abstract

contraption for solar energy, in particular solar collector (1), with at least one absorber element (2), the at least one fluid channel (4) characterized in that the Fluid channel (4) has at least one kinked flow path.

Description

The Invention relates to a device for solar energy production, in particular a solar collector, according to the preamble of the protection claim 1 and a method for producing such a device according to the generic term of the protection claim 15 and the use of such a device according to the generic term of the protection claim 16.

devices for solar energy, in particular solar or solar panels have been known for some time and have been used for some time, to radiation emanating from the sun, in short solar energy, into thermal Energy to convert, usually a transmission fluid, such as Water, oil or a gas is heated up. This transfer fluid usually becomes transported in one or more fluid channels, so that the the thermal energy inherent in the fluid can be used elsewhere.

One central component of such a device for solar energy and in particular a solar collector is an absorber element. This absorber element serves to absorb energy, which in is generally available as radiation emanating from the sun. This absorber element comprises at least one fluid channel in which the transmission medium, namely the transmission fluid, guided becomes.

A energetically efficient use an absorber element hangs of two principal factors. These are on the one hand, the thermal cal Efficiency, ie the efficiency of heat transfer to the fluid, as well a hydraulic power, namely the flow of the fluid in the fluid channel.

Regarding one possible efficient transmission of heat One important aspect of the fluid is one or more fluid channels preferably evenly in that To arrange absorber element, so that, if possible, the entire of the outside supplied to the absorber element Transfer energy to the fluid becomes.

In In the past, for this purpose, a fluid channel was built in one Absorber element used, the meandering or serpentine in the absorber element, wherein This variant also arranged a plurality of fluid channels in series one behind the other could be. A disadvantage of this construction, however, is in the big Fluid channel length, which leads to a high pressure loss.

to solution This problem has been in the past instead of a long one serially extending fluid channel multiple short parallel fluid channels, for example in the form of parallel tubes, which run between two collection channels. Such a harp absorber with several parallel arranged fluid channels However, has the disadvantage that the arranged in parallel fluid channels the absorber is flowed through unevenly, which is due to a pressure loss during the transition of the fluid is based on a collection channel in the parallel tubes.

One Another type of absorber known from the prior art is a Cushion absorber, the entire surface flows through becomes. Again, a uniform volume flow distribution, especially when only low flow rates are promoted, difficult to realize.

One further, all of these aforementioned Absorbertypen common problem is further that a complete Discharge these known absorber types and geometries in the most cases is problematic, since these are known from the prior art Absorbers frequently Dead spaces and / or Have undercuts that allow easy run out of fluid from the absorber element, respectively from the fluid channel or the fluid channels out, as well as a venting when filling of the absorber element, prevent. This problem occurs in particular in recent Meander and Serpentine absorbers, but also on Harfenabsorbern on.

Of the Invention is based on the object, a device for solar Energy production, in particular a solar collector, a method for producing such and the use of such a device to disposal to provide, in which the aforementioned problems are significantly reduced and a heat transfer is improved to a heated by the device fluid.

These The object is achieved by a device according to protection claim 1, by a Method according to protection claim 15 and by a use according to protection claim 16 solved. In particular, the object is achieved by a device for solar energy generation, in particular solar or solar collector, with at least one absorber element, the at least one fluid channel comprises, wherein the fluid channel at least a kinked flow path having.

An essential point of the invention is that it is largely avoided by a kinked flow path that the fluid channel is flowed through by a fluid having a laminar flow profile, since a kink in the flow path of the fluid channel, a turbulent flow is generated by which advantageously Wei an increase in the thermal efficiency of the absorber element is effected. This effect is due to the fact that in a turbulent flow in the cross section of the fluid channel almost no temperature gradients can form within the guided in the fluid channel fluid, since fluid which has been heated on a warm side of the absorber element, by the turbulence of the flow immediately is mixed with cooler fluid that has not been in direct contact with a warm side of the absorber element. At the same time as the fluidizing of the fluid already heated on the warm surface of the absorber element, this warm surface is immediately supplied with cooler fluid owing to the turbulent flow, which due to a larger temperature difference between the not yet heated or only slightly heated fluid and the warm absorber surface an increased amount of thermal Can absorb energy.

One An essential advantage of the invention is that of previously described Way the heat transfer and therefore the heat efficiency a solar collector equipped with such an absorber element on simple and inexpensive Way can be significantly increased.

According to one embodiment the invention is the kinked flow path in one and / or formed as a deflection region of the fluid channel.

According to this embodiment can the kinked flow path be obtained that the Fluid channel is deflected so that the flow path past a bend or over a kink flows, by causing as described above, that a laminar flow with all the benefits that go with it turn into a turbulent flow.

At this point should be mentioned the existence kinked flow path can also be generated in a simple manner that in the Fluid channel a bottleneck, for example, due to a fitment or an edge in the fluid channel. Such a kinked flow path For example, by a ramp-like flow guidance or by a Rotation of the fluid in the fluid channel triggering local or through the entire fluid channel extending guide can be generated.

According to the invention, the kinked flow path closes an angle of preferably 90 °, in particular in the range of 90 ° to 105 ° and particularly preferably in the range of 90.5 ° to 95 ° and / or an angle of <90 °, in particular in the range of 89.5 ° to 85 °.

It it should be noted that the Fluid channel of the device according to the invention, if desired, several kinked flow paths may, for example, in serial arrangement within the fluid channel are arranged. These multiple kinked flow paths within a fluid channel have different angles, with angles being preferred, the bigger or are equal to a right angle, since such angles, in particular in the range of 90.5 ° to 105 ° optimal Compromise between an occurring pressure loss of the fluid in the fluid channel and represent the effect of a turbulent flow in the fluid channel. An angle of less than 90 ° can be advantageous if the fluid is a very low density has or gaseous is.

According to one embodiment the invention, the fluid channel is formed substantially meander-shaped. The main advantage of this embodiment is that a meandering trained Fluid channel extending between a fixed input and a stationary Spout extends, has a much greater length than a linear fluid channel, in a straight line between this stationary enema and extends this fixed spout. In this way is a heat transfer route a meandering extending Fluid channel opposite a linearly extending in a straight line fluid channel clearly enlarged, what again a positive influence the heat transfer efficiency the device according to the invention causes.

According to one another embodiment the invention runs at least one meandering turn the fluid channel substantially trapezoidal, wherein the meandering turn the leg defining the fluid channel in the form of three sides of a Trapezes are arranged, wherein the course of the fluid channel through the two non-parallel legs of the trapezium and, preferably, through the shorter one the two parallel sides of the trapezoid is formed.

According to one embodiment of the invention formed the two non-parallel legs of different lengths be, with the help of an imaginary, in case equal long non-parallel thigh that complete trapeze Line, a trapezoid arises, which consists of four not parallel to each other Pages is formed.

According to the invention, respective inner angles α of trapezoidal sections of a meandering fluid channel are substantially the same. In this way, a simple manufacture of the device according to the invention is possible, since a fluid channel, for example in the form of a pipeline or a channel guide in an absorber element wall, only with an angle measure in terms of its internal angle must be edited. In this way it is easily possible to produce a uniform meandering and / or trapezoidal fluid channel.

According to one particularly advantageous embodiment the invention is the absorber element as Rollbond absorber element formed, with two, if desired the same thickness or different thickness Aluminum plates, each with, complementary in superposition Channel sections are provided, pressed together or otherwise connected, for example, welded or glued. The in the aluminum plates provided channels, if the two Aluminum plates on top of each other are arranged, each having a fluid channel, which is a heat transfer fluid can record. The formation of the absorber element as Rollbond absorber element is particularly advantageous because no pipes in the absorber element have to be arranged but the fluid channel running in the absorber element directly by the absorber element limiting metal, in particular Aluminum plates is formed, wherein provided in the metal plates channels For example, by means of pressure in these are imprinted. An advantage of such Rollbond absorber elements is moreover that heat from the absorber bounding metal plates, preferably aluminum plates, pass directly to the guided in the fluid passage fluid without heat loss can. It should be explicitly noted that according to the invention except the Material aluminum also other metals with good thermal conductivity can be used for the production of the absorber element.

Of Further, it is within the scope of the invention that the absorber element with a Plurality of fluid channels is designed in the form of a Harfenabsorbers. The advantage founded in it the device according to the invention lies in the fact that the Heat transfer efficiency of the inventively designed Absorber element by a multiple arrangement of fluid channels in one Absorber element can be significantly increased. Furthermore a pressure loss in each individual fluid channel can be reduced because of the use of multiple fluid channels in an absorber element each individual fluid channel is shorter in its fluid channel length can be without the total volume the Ubertragungsfluids, which in all fluid channels of the Absorber element is located, would be reduced.

Run according to the invention the fluid channels of a Harp absorber between a manifold and a header pipe. The fluid flows here first into a manifold and from within it from the manifold path extending fluid channels, which according to their Main direction extending in the direction of the collector tube, which that from the fluid channels outflowing Take up fluid and then can be used for further use.

Of others have the distributor and / or the collector tube with respect their longitudinal extent an end, but preferably at each end, has an external connection over which a fluid in the absorber element, respectively in the fluid channel initiated or can be diverted away from this.

The Provision of two external connections each on the manifold and increased at the collector tube the installation variability the absorber element in a device according to the invention, in particular a Solar collector according to the invention. About that In addition, in the case of Providence of two external connections one funded by the absorber element Fluid flow compared to only one external connection on the manifold and significantly increased at the collector tube. Furthermore is the providence of two external connections each the respective distributor and the collector tube with respect to a thermally efficient removal of the heated Fluids advantageous because it is ensured in this way that no heated fluid in the absorber element, for example, remains in a dead space, in the case of the Providence of only one external connection to the Distributor tube and / or would not flow through the collector tube.

Of others have the distributor and the collector tube along their respective longitudinal extent at least one, preferably up to 50 and more preferably until to 10 connections for fluid channels. In the area of these connections can each advantageously a kinked flow path in the respective fluid channels be present, namely directly in the connection region of the fluid channel the manifold to an optimized flow of fluid from the manifold into the respective fluid channels to ensure. For this purpose, the fluid channels are provided with a chamfer attached to the manifold to expand a funnel-like To allow access from the manifold into the respective fluid channel. This funnel-like expansion of the fluid channels increases in dependence the distance from an external terminal connected to the manifold is provided. In this way it is possible to remove fluid from the manifold targeted to initiate a respective fluid channel and a pressure drop in the transition area of manifold and fluid channel to minimize.

Furthermore, a pipe diameter of the distributor and / or the collector tube is larger in the particular by a factor of 2 to 10 greater than a pipe diameter of a fluid channel.

There a device according to the invention usually not flat, d. H. not in horizontal position, but is used with a certain inclination, wherein the absorber element flows through from bottom to top is this embodiment is particularly well suited to vent the absorber element, d. H. its fluid channels homogeneous and even with the transmission fluid to fill, the fluid over an external connection first in the Distributing pipe flows in, this fills up and subsequently into the individual fluid channels a harp absorber pressed is to at the upper end of the respective fluid channels out of these out into the collector tube to stream. By the provision such a buffer volume in the form of a manifold can an uneven filling of the fluid channels and thus unequal flow conditions in the fluid channels be avoided, which in turn to an increase in efficiency in heat transfer the absorber element and thus the device according to the invention contributes.

To For this purpose, it is particularly advantageous if an input and / or an outflow opening of Fluid over an external connection in the manifold or from the collector tube with respect to a and / or an outflow direction of fluid in or out of a fluid channel at an angle, preferably at an angle of substantially in the range of 90 ° ± 10 °. On this way is guaranteed that fluid not directly from an external terminal in an inflow opening of a Fluid channel flows and in this way defines a preferred fluid channel, but that all fluid channels are filled equally, after the distributor pipe has been completely filled up. Also in the further operation is in this way by the relatively large pipe diameter of the manifold ensures that a uniform distribution of the fluid to all fluid channels he follows.

Of another is provided according to the invention, that yourself the respective external connections extend in a direction that the orifices for fluid channels substantially is opposite.

According to this embodiment is ensured in a simple way that at an opening the external connections the fluid, especially at angles of the kinked flow path from ≥ 90 ° directly from the absorber element may leak if this inclined or perpendicular is provided.

Of Furthermore, the object of the invention by a method for Producing a device for solar energy production, in particular Solar collector according to the preceding versions solved, wherein the absorber element according to the invention produced in the Rollbond process becomes.

Further The object is achieved by the inventive use of such Device in a solar collector system in which one or more above-described absorber element (s) or complete devices according to the invention are, solved.

In a particularly preferred embodiment of the invention, the absorber of the device according to the invention in Rollbond process of two compressed, ie cold-welded, equal or different thickness aluminum plates produced, which are provided with channels that are expanded by the application of pressure, and in which a joining of the aluminum plates, the fluid, namely the solar fluid or the heat transfer medium flows. The channels are designed so that the collector can be provided with four connections and thus has a symmetrical 4-pipe connection option. In inclined installation is thus below a distributor and integrated above a collector tube, which are each designed so that no airbag or other hollow and / or dead space can form, so that a completely independent emptying is guaranteed at any time. Furthermore, it is ensured according to the invention that, through the special construction according to the invention of the distributor tube at the bottom and the collector tube at the top, the individual fluid passages designed as riser passages are flowed through uniformly. The channel cross-section of the manifold is sized so that, for example, up to 10 fluid channels can be connected in series. The distance between the riser and fluid channels, usually four pieces, is relatively large in relation to conventional Cu / Cu or aluminum / copper absorber elements, since the heat transfer medium channels, namely the fluid channels, are embedded directly in the absorber element sheet and a Heat transfer resistance in an absorber element, which has been produced by the Rollbondverfahren, is not present or extremely low. The fluid channels extending between the lower manifold and the upper manifold tube are preferably meandered or trapezoidal arranged so that they extend steadily rising at a vertical absorber element, so that when opening the external terminals, a safe leakage of the fluid from the Absorber element is ensured and the absorber element can be safely vented during commissioning of the device according to the invention. In addition, a significant extension of the fluid channels is made possible by the trapezoidal routing of the respective fluid channels and a turbulent flow profile is achieved in the fluid channels, whereby the heat transfer from the plates the absorber element on the heat transfer medium significantly improved.

Further embodiments The invention will become apparent from the dependent claims.

following the invention will be described by means of exemplary embodiments, the closer to the pictures explained become. Hereby show:

1 a schematic view of an embodiment of an absorber element according to the device according to the invention in plan view;

2 a schematic detail according to the in 1 embodiment shown;

3 a schematic representation of a cross-sectional view in the stage of production of an embodiment according to 1 before a roll bonding of the absorber element; and

4 a schematic representation of a cross section of the embodiment according to 1 ,

In The following description will be for the same and the same Share the same reference numbers, possibly using quotes used.

1 shows a schematic representation of an absorber element according to an embodiment of the inventive device for solar energy. The absorber element 2 includes four meandering between an inlet manifold 36 and a drain collector 38 extending fluid channels 4 . 4 ' . 4 '' . 4 ''' , The feed distributor 36 has at its two ends in each case an external connection 40 on. An inlet from these connections 40 in the inlet manifold 36 extends substantially in a direction that the terminals 41 the fluid channels 4 to 4 ''' to the inlet manifold 36 is opposite. Furthermore, in 1 shown that meandering turns of the fluid channel in the form of three-part sections of a trapezium are present, which are each connected via their non-parallel legs with each other and obtained in this way a meandering course.

In 2 is a detailed representation of these meandering turns of the fluid channel 4 shown. In particular, goes out 2 show that the respective internal angles α, α 'of the respective trapezoidal sections are identical and enclose an angle of 95 ° (not drawn to scale). These angles α, α 'are defined by the legs 10 . 12 . 14 and 16 formed, wherein these respective inner angles α, α 'respective deflection regions 8th . 8th' . 8th'' . 8th''' assigned. The respective associated trapeze are denoted by the reference numerals 6 . 6 ' and 6 '' designated.

In particular from 1 combined with 2 can be seen well that a fluid path from the external terminals 40 of the feed distributor 36 over the fluid channels 4 . 4 ' . 4 '' . 4 ''' to the drain collector 38 and from there to its external connections 40 ' steadily rising extends when the absorber element 2 is positioned so that the inlet manifold 36 below 20 and the drain collector 38 upstairs 22 located. In this way, a simple filling of the absorber element 2 over the external connections 40 of the feed distributor 36 easily possible without an air space in the absorber element 2 remains if this from below 20 up to the top 22 completely filled. In this way is a venting of the absorber element 2 easily possible. Conversely, the absorber element, due to the constantly decreasing lines from the external terminals 40 ' up to the external connections 40 be emptied easily.

According to the in 1 shown absorber element comprises this total of four fluid channels 4 to 4 ''' that run parallel.

The 3 and 4 show a cross section of the embodiment according to 1 together with a cover plate 42 and an insulating layer 32 in a schematic representation, wherein in 3 a still unfinished intermediate stage in the course of the manufacturing process of the absorber element 2 is shown.

The absorber element 2 of the solar collector 1 consists of two aluminum plates 2a and 2 B in which fluid channel sections 4a and 4b are formed. When assembling the aluminum plates 2a and 2 B become these fluid channel sections 4a and 4b so joined together in an associated manner that from these two sections 4a and 4b one fluid channel each 4 is formed. A joining of the two aluminum plates 2a and 2 B via roll bonds, which are cold-welded by the application of pressure.

When using the absorber element 2 in a solar collector according to the invention 1 this one is with its top 3 facing the sun, so that the absorber element 2 and subsequently in the fluid channels 4 Absorber fluid located 34 is heated by the solar energy. To improve the efficiency of the inventive device for solar energy, in particular solar collector 1 , is the bottom 5 of the solar collector 1 with an insulating layer 32 Mistake.

Due to the immediate arrangement of the meandering fluid channels 4 in the absorber element 2 and the provision of kinked flow paths in the fluid channels 4 is the efficiency of the solar collector according to the invention 1 compared to those according to the prior art significantly increased. This inventive very high efficiency of the device according to the invention is based primarily on the very efficient generation of turbulent flow profiles in the fluid channels by the provision of kinked flow paths claimed in the invention in the fluid channels and beyond a very low heat transfer resistance between the absorber element and the absorber fluid 34 ,

Due to this optimized efficiency, the distance of the individual in the absorber element 2 arranged fluid channels are dimensioned to each other larger than conventional Cu / Cu or Alu / Cu absorber elements, without fear of lower energy efficiency, resulting in reduced manufacturing costs of the absorber element 2 a device according to the invention in contrast to previously known absorber elements expresses.

At It should be noted that all parts described above for themselves seen alone and in any combination, especially those in the Drawings illustrated details claimed as essential to the invention become. amendments this is familiar to the person skilled in the art.

1

solar collector

2

absorber element

3

top

4

fluid channel

5

bottom

6

trapeze

8th

deflection

10

leg

12

leg

14

leg

16

leg

20

below

22

above

32

insulation layer

34

absorber fluid

36

inflow distributor

38

drain collector

40

external Connection

41

Connection for fluid channel

42

cover

Claims (14)

Apparatus for solar energy production, in particular a solar collector ( 1 ), with at least one absorber element ( 2 ), the at least one fluid channel ( 4 ), characterized in that the fluid channel ( 4 ) has at least one kinked flow path. Apparatus according to claim 1, characterized in that the kinked flow path in one and / or as a deflection region ( 8th ) of the fluid channel ( 4 ) is trained. Device according to one of the preceding claims characterized in that kinked flow path an angle of preferably ≥ 90 °, in particular in the range of 90 ° to 105 ° and especially preferably in the range of 90.5 ° to 95 ° and / or an angle of <90 °, in particular in the range of 89.5 ° to 85 ° includes. Device according to one of the preceding claims, characterized in that the fluid channel ( 4 ) is substantially meandering. Apparatus according to claim 4, characterized in that at least one meandering turn of the fluid channel ( 4 ) is substantially trapezoidal and / or trapezoidal. Apparatus according to claim 5, characterized in that respective inner angles (α) of trapezoidal sections of a meandering fluid channel ( 4 ) are substantially the same size. Device according to one of the preceding claims, characterized in that the absorber element ( 2 ) is designed as a roll-bond absorber element. Device according to one of the preceding claims, characterized in that the absorber element ( 2 ) having a plurality of fluid channels ( 4 ) is designed as Harfenabsorber. Apparatus according to claim 8, characterized in that a distributor ( 36 ) and / or collector tube ( 38 ) are provided, between which the fluid channels ( 4 ) of a harp absorber. Apparatus according to claim 9, characterized in that the distributor ( 36 ) and / or the collector tube ( 38 ) with respect to its longitudinal extension at one end, preferably at each end an external connection ( 40 ) exhibit. Device according to one of the preceding claims 9 or 10, characterized in that the distributor ( 36 ) and the collector tube ( 38 ) along its longitudinal extent at least one, preferably up to 50 and more preferably up to 10 ports for fluid channels ( 4 ) exhibit. Device according to one of the preceding claims 10 or 11, characterized in that the respective external connections ( 40 ) and / or an inlet or outlet to / from these connections ( 40 . 40 ' ) extend in a direction corresponding to the terminal (s) ( 41 ) for fluid channels ( 4 ) is substantially opposite. Device according to one of the preceding claims, characterized in that a pipe diameter of the distributor ( 36 ) and / or the collector tube ( 38 ), in particular by a factor of 2 to 10, is greater than a pipe diameter of a fluid channel. Device according to one of the preceding claims 8 to 13, characterized in that an inlet and / or a discharge direction of fluid via an external connection ( 49 ) in the manifold ( 36 ) or from the collector tube ( 38 ) with respect to an inlet and / or outflow direction of fluid into or out of a fluid channel ( 4 ) at an angle, preferably at an angle substantially in the range of 90 ° ± 10 °.