EP4257909B1 - Heat storage unit - Google Patents

Description

The invention relates to a heat storage unit with at least one storage block, which is designed as a bundle of several parallel, longitudinally extended in the z-direction, closed hollow chambers made of hollow profiles, each of which is filled with PCM material, wherein in the cross-sectional plane extending in the xy-direction, at least two hollow chambers with wall sections (a, b, c, d) of their peripheral walls are arranged in a planar manner directly or indirectly via a thin, highly heat-conducting contact layer in the x-direction as well as in the y-direction of the storage block, the peripheral walls are provided with depressions running in the longitudinal direction over their entire length in at least one part of their wall sections (a, b) lying opposite one another in pairs, the depressions in the peripheral walls of two adjacent hollow chambers complement each other in cross-section to form a closed, in particular circular, ring, and a line arrangement is led through the storage block for passing through a heat-transporting fluid, said line arrangement comprising at least one line with several line sections, which are inserted into the recesses directly or via a heat conducting medium contact are thermally conductively connected to the adjacent areas of the peripheral wall and via this to the PCM material. Furthermore, the invention relates to a method for assembling such a heat storage unit. A heat storage unit according to the preamble of claim 1 is made of EN 2020 19105940U known.

A heat storage unit of this type and also assembly steps for its assembly are described in the applicant's WO 2021/078437 In this known heat storage unit, depressions are provided, particularly in the edge areas of hollow chambers that run parallel to one another and are formed from square hollow profiles, and are inserted into the line sections of a line arrangement in order to guide a heat transfer fluid, in particular water, through. A so-called phase change material, PCM material, is filled into the hollow chambers in order to temporarily store heat contained in the heat transfer fluid and to release it back to it when required. The hollow chambers, which are thus combined from several to form a bundle, are encased on the circumference in thermal insulation material and, with regard to their vertical orientation, are accommodated in a base at the bottom and covered at the top by a thermal insulation cap. Although this structure enables a cost-effective method of production, there is still room for improvement for the most efficient use of energy.

In the EP 2 468 977 A1 a surface element is shown with a heat-conducting shell that surrounds a phase change material, whereby the surface element is directly or indirectly in heat-conducting connection with a heating or cooling line. By encasing the phase change material (PCM material) in plate or slat form, this material can be easily integrated into heating or cooling ceilings or also into wall and underfloor heating, whereby a hollow profile or a plate filled with PCM material can be arranged in heat-conducting connection with a concrete ceiling. In one embodiment, two hollow profiles can each be provided with a recess on adjacent side surfaces in order to accommodate a line for a heat-conducting fluid and to enclose it over the entire surface. The adjacent side surfaces are provided with a retaining element arrangement consisting of T-shaped grooves on the one hand and webs adapted to these on the other, so that they can be pushed into one another or plugged into one another in the longitudinal direction to create a positive connection. However, it is difficult to achieve simple assembly and at the same time a tight connection between the heat-transferring components for good heat conduction.

Another heat storage unit is in the EN 20 2018 100 856 U1 shown. In this known heat storage unit, a heat storage or buffer storage, which is designed to supply service water, in particular heating and/or drinking water, is surrounded on the outside of its container wall in a heat-conducting manner by a pocket-like carrier into which a phase change material (PCM material) is filled. In this design, too, heat can be stored latently, ie essentially without a change in temperature, as a result of a phase change, using the phase change material in a manner known per se.

The EN 10 2017 125 669 A1 shows a bundled arrangement of, for example, rotationally symmetrical hollow bodies as heat storage elements in which latent heat storage medium is accommodated. The heat storage elements are arranged in a first container section of a container and are open to a second container section of the container. The heat storage elements with the latent heat storage medium are surrounded in the first container section by a heat transfer medium (in particular water) that flows through a third cavity of the container, which surrounds the second container section. The open heat storage elements are intended to enable volume changes of the heat storage medium and to achieve the same thermodynamic equilibrium states in the heat storage elements.

The EN 10 2011 004 202 A1 shows a latent heat storage element with a circular-cylindrical outer shape, in which latent heat storage material is accommodated together with a matrix made of a material with increased thermal conductivity compared to the latent heat storage material. When several such latent heat storage elements are arranged in an energy storage device, the individual latent heat storage elements are surrounded by a heat transfer fluid.

The EN 20 2010 000 027 A1 shows a further latent heat storage device with a line arrangement arranged in a container and held therein by means of a support structure, in which a heat transfer fluid is guided, wherein the heat storage medium is arranged in heat-conducting contact with the line system in the cavity surrounded by the outer casing.

The EN 10 2009 036 550 A1 also shows a latent heat storage system. Here, two sub-areas are formed for the piping system carrying the heat transfer medium and the heat storage medium, and the heat transfer medium (working medium) is also guided through flow spaces that are formed in the storage medium itself. The storage medium is designed, for example, as a one-piece, monolithic solid body with flow spaces running through it or as a bulk solid body.

Also the EN 10 2011 107 270 A1 shows a heat storage device with a container filled with a fluid, in particular water, in connection with an arrangement of phase change material for storing thermal energy. The phase change material is arranged in bodies in the fluid that are connected to the fluid in a heat-conducting manner or, in another embodiment, is housed in a storage extension in the form of a shell-like or layer-like additional casing on the outside of the container. Layered heat storage devices are also specified, with the layers containing fluid at different temperatures. and the layers are assigned phase change materials with different transformation or transition temperatures (threshold temperatures).

In a EN 10 2013 114 507 B3 In the further embodiment for a heat storage unit shown, a container with a mixture of phase change material and graphite powder is disclosed. The phase change material is introduced into a space between an inner and outer container wall.

In the US 2011/0239673 A1 is shown an apparatus for heating water comprising a hot water storage tank, a heating arrangement arranged to heat water in the storage tank, and a heat exchange device arranged in the heat storage unit in a fixed relationship relative to a position of the heating arrangement, the heat exchange device comprising a hollow object and a phase change material within the hollow object.

Other similar heat storage facilities are in the WO 2012/167934 A2 , the WO 2015/121039 A1 , the EN 10 2011 053 788 A1 , the WO 2010/092391 , the EN 10 2015 205 626 A1 , the EP 2 713 130 A2 and the CN2 01 503 135 U as well as in the DE 20 2016 102 914 U1 which shows a buffer tank in which phase change material is positioned in the water of the buffer tank by means of a carrier device.

Equipping the storage tanks with the phase change material always requires a considerable amount of effort and, if necessary, space.

Known designs of the above-mentioned type of heat storage systems feature relatively extensive design measures that prevent simple installation, additions and conversion options as well as efficient operation.

The present invention is based on the object of providing a heat storage unit which results in the most efficient operation possible with the least possible manufacturing effort and the widest possible range of uses, in particular in connection with storage containers for hot water or similar fluids, and of specifying a method for producing the heat storage unit.

This object is achieved in a heat storage unit with the features of claim 1. In this case, it is provided that a line arrangement for conducting a heat-transporting fluid is guided through the storage block, that the storage block is designed as a bundle of several longitudinally extended closed hollow chambers that run parallel to one another and are tightly adjacent to one another with wall sections of their peripheral walls (directly or via a thin intermediate layer with good heat conduction), each of which is filled with PCM material, that the peripheral walls are each provided with depressions running in the longitudinal direction, and that the line arrangement has at least one line with several line sections that are connected in the depressions in a heat-conducting manner to the adjacent areas of the peripheral wall and via a heat-conducting agent in a heat-conducting manner.

The storage block, designed as a bundle of several hollow chambers that are tightly connected to one another with their peripheral walls and are closed on all sides and contain the phase change material, results in a compact heat-storing unit that is not installed in a container filled with liquid, for example, and is easy to handle due to its structure and offers good spatial storage options. The bundle of several hollow chambers arranged next to one another in the x and y directions can be assembled simply by joining them side by side using the holding element arrangements, which also form a tight, compact, good heat transfer supporting the juxtaposition of the hollow chambers, and can also be held together, for example, by external bands or belts and/or a heat-insulating covering and/or a material connection that conducts heat well. The wall thicknesses of the peripheral walls of the hollow chambers can be thin, e.g. in the range of one or more mm, e.g. between 0.5 and 3 or 4 mm, and yet still be stable, and the cross-sectional dimensions of the chambers can, for example, be between 1 cm and 10 cm, e.g. between 3 cm and 5 cm or 8 cm for a square or rectangular cross-section, or can deviate from these dimensions if necessary, depending on the required size or storage capacity of the storage block.

The cable sections can be inserted tightly and in close contact with the surrounding wall sections, for example by means of an adhesive or sealing material, so that damage between different materials, especially metals, as a result of different electrochemical potentials can be avoided while at the same time ensuring good heat transfer.

The measures according to the invention contribute to efficient operation and a compact structure, in that the hollow chambers, which are closed on all sides, are each formed from hollow profile bars that are closed all around. The hollow profile bars can be easily provided in a suitable length (e.g. by cutting a longer hollow profile bar to length) and in a suitable number. They are preferably firmly closed on one end (on the lower side when installed vertically) and, when filled, are also firmly or preferably openably closed on the other side (on the upper side when installed vertically) with a cover part or a closure element that can be opened therein, whereby any changes in volume can also be compensated for via the cover part.

For the construction of the heat storage unit, the invention provides that individual hollow chambers, which are provided with rectangular or square hollow profiles, are closely joined together in a row direction (x or y) by means of holding element arrangements formed on the outside of their peripheral walls with mutually complementary holding elements running longitudinally in the z direction to form a layer of several adjacent hollow chambers, with line sections being inserted into recesses between wall sections of the hollow chambers, that several layers of joined hollow chambers are layered on top of one another with their end wall sections oriented at right angles to the row direction, that the layers placed on top of one another are held together to form a bundle by means of at least one folded-over band and/or by means of a cap placed on top of at least one end section of the bundle and/or a base placed on bottom, that the line sections are connected to form a line arrangement via connecting pieces, and that the storage block is encased on the circumference by means of heat-insulating material before or after the cap and/or the base are placed on.

Advantageous embodiments are specified in the subclaims. For bundling and compact assembly with good heat transfer, the measures are advantageous that the hollow chambers formed from hollow profiles with their peripheral walls except for the depressions and holding element arrangements and possibly a recessed edge area next to the holding web each have an identical, essentially rectangular or square cross-section with wall sections (c, d; a, b) that are plane-parallel to the x-z plane and the y-z plane, and that the hollow chambers lined up in the x direction with their two wall sections (c, d) oriented in the x-z plane and the hollow chambers lined up in the y direction with their two wall sections (a, b) oriented in the y-z plane are aligned with one another.

An advantageous assembly when several hollow profiles or hollow chambers are arranged side by side in a single layer is made possible by that for each hollow profile only one wall section (yz plane or xz plane) extending at right angles to a row direction (x or y) is provided with a suspension groove (14) and only the other wall section (yz plane or xz plane) extending at right angles to this row direction (x or y) is provided with a retaining web, wherein the suspension groove and the retaining web of the hollow profile are at the same distance (d) from the same wall section (xz plane or yz plane) extending in the row direction (x or y), so that the latter wall sections in the row direction (x or y) of adjacent hollow profiles lie flush in a common plane when assembled.

The assembly when placing adjacent hollow profiles or hollow chambers and also the insertion of the line sections into opposing recesses is further facilitated by the fact that the wall section (a) in which the hanging groove is arranged is flat except for the groove opening of a clear opening width and at least one recess and otherwise extends to the profile edges that delimit it and run in the z-direction and are possibly slightly rounded, that the clear opening width of the hanging groove is at most one sixth or eighth of the width of the wall section in question and that the holding groove is arranged closer to one of these two profile edges than to the other profile edge with respect to the center of its groove opening, in particular in the outer edge-side quarter of this wall section, wherein the distance between the edge-side opening edge of the holding groove and the near profile edge corresponds (essentially) to the distance between the side of the projection part of the holding web adjacent to the opening edge and the near profile edge, so that the Wall sections of adjacent hollow profiles are aligned with each other.

If it is intended that the wall section (b) provided with the retaining web is provided with a widening outwardly towards the edge area in the area between the edge-side attachment point of the projection part and the near profile edge of this hollow profile Recess, in particular beveled at an angle, in relation to its (extended) contact plane, two hollow profiles or hollow chambers to be assembled can initially be positioned at an angle to one another with respect to the alignment direction and joined together with their holding elements (holding groove and holding web) in or against the alignment direction and then pivoted against one another about the z-axis until they lie tightly (closely) against one another with their contact surfaces of the wall sections facing one another. Before they are completely pivoted together, a line section can simply be inserted, if necessary after applying a suitable heat-conducting contact layer.

A reliable connection between hollow profiles or hollow chambers joined together by means of their holding elements is ensured by the fact that the clear opening width of the groove opening is larger than the thickness of the projection part of the holding web measured in the same direction but smaller than the sum of the thickness of the projection part and the length of the retaining lug protruding in the same direction and engaging behind the holding edge when assembled, which is at most as long as the width of the holding edge in this direction, and that the groove depth is larger than the length of the projection part with the holding lug in the depth direction of the hanging groove. The hollow profiles joined together cannot be pulled apart in the direction of alignment. The projection part is rounded on its side facing away from the holding lug in the transition area to the holding lug so that the holding web can be inserted and pivoted into the holding groove at an angle without hindrance during assembly.

Advantageous design options consist in the fact that the depressions - with respect to an imaginary shape that is not recessed and not provided with a holding element arrangement - are arranged along flat wall sections of the peripheral wall.

A particularly good heat transfer between the fluid flowing through the pipe sections, in particular water, and the phase change material is achieved by the fact that the peripheral walls of the hollow chambers are made of metal, in particular aluminum.

A further advantageous design for production and function with good heat transfer is that the line sections are made of metal, in particular copper.

A functionally advantageous embodiment consists in that in each wall section of each polygonal hollow profile, in particular rectangular or square hollow profile, a recess is arranged centrally with respect to the cross-sectional width of the wall section, and further in that the hollow chambers are tightly closed on both sides at the front with a cover part, wherein in particular an upper cover part in the erected state is provided with an openable closure part.

For connection to a storage tank, such as a hot water tank, or a group of storage tanks or another hot water supply system, it is advantageously provided that the line arrangement has at least one inlet section and at least one outlet section for connection to a hot water tank. Either a line that runs through the entire storage block between the hollow chambers or their peripheral walls can be connected to an inlet section or outlet section, or several line sections can branch off in parallel from an inlet section or outlet section, so that, for example, a lower flow rate can be achieved through the individual line sections with flow rates that are advantageous in accordance with the heat transfer times.

Different sizes of heat storage units in terms of geometry and/or heat storage capacity can be provided simply by combining several storage blocks in the longitudinal direction (z-direction) adjacent to one another and/or in the transverse direction (x-y direction) next to one another to form a storage block unit.

Within a storage block, PCM materials with relatively different transformation temperatures can also be filled into the individual hollow chambers, for example in suitable groupings of hollow chambers, whereby the line arrangement can also be provided with several inlet sections and outlet sections as well as associated line sections in order, for example, to store heat appropriately or specifically according to the temperature of different fluid layers or water layers within the storage container.

Precise assembly and good function are also helped by the fact that the bundle of hollow chambers of a storage block is formed from several hollow chambers arranged linearly in a row direction (x-direction or y-direction perpendicular to the z-direction or longitudinal direction), held together by the holding element arrangement to form a hollow chamber layer, and several layers placed on top of each other with their two end wall sections aligned with one another in one plane.

The assembly and function are also facilitated by the fact that the bundle of hollow chambers of a storage block is held together by means of at least one folded, tensioned band.

The measures that the bundle of hollow chambers of a storage block is accommodated, in particular inserted, with a lower end section in a heat-insulating base and that the bundle is circumferentially and on its upper side is encased in an external insulation made of, in particular, plate-shaped, thermal insulation material.

In connection with the construction procedure, it is advantageous that there are also recesses between the layers in the wall sections of the hollow profiles, into which the line sections of the line arrangement are inserted.

Fig. 1A

eine (geöffnete) Wärmespeichereinheit mit einem Speicherblock in perspektivischer Ansicht,

Fig. 1B

einen vergrößerten Ausschnitt A des Speicherblocks nach Fig. 1A,

Fig. 2A

ein Bündel aus vier seitlich nebeneinander angeordneten Hohlprofilstäben - zwei in x-Richtung und zwei in y-Richtung - in Draufsicht in Richtung der Längsachse und

Fig. 2B

einen Ausschnitt A nach Fig. 2A zweier in x-Richtung nebeneinander angeordneter Hohlprofilstäbe im Bereich einer Halteelementanordnung in Draufsicht in Richtung der Längsachse.

The invention is explained in more detail below using exemplary embodiments with reference to the drawings.

Fig. 1A

an (open) heat storage unit with a storage block in perspective view,

Fig. 1B

an enlarged section A of the memory block after Fig. 1A ,

Fig. 2A

a bundle of four hollow profile bars arranged side by side - two in x-direction and two in y-direction - in plan view in the direction of the longitudinal axis and

Fig. 2B

a section A after Fig. 2A two hollow profile bars arranged next to each other in the x-direction in the area of a holding element arrangement in plan view in the direction of the longitudinal axis.

Fig. 1A shows a storage block 3 of a heat storage unit 1 extending along a longitudinal axis (in direction z) with a bundle of closely packed hollow profile bars 10 forming hollow chambers and a line arrangement 2 with line sections 23 running in the longitudinal direction between the hollow profile bars 10 (cf. enlarged section A in Fig. 1B ). The line sections 23, which are connected to one another in a fluid-conducting manner via intermediate pieces, form parts of lines 20, which are connected on the inlet side to an inlet section 21 and on the outlet side are fluidly connected to an outlet section 22 for supplying or discharging a fluid (heat transfer fluid), in particular a liquid, preferably water or a similar liquid.

The formation of the hollow chambers from the hollow profile bars 10 results in design options for storage blocks 3 that can be easily adapted to the respective requirements. The hollow profile bars 10 can be cut to the desired length from longer hollow profiles. They are filled with a phase change material (PCM material) in their cavity 11 and, after filling in the PCM material, are sealed tightly at the front, with the closure of one front side (the lower one when installed vertically) advantageously being permanently attached and the closure on the other front side (the upper one when installed vertically) advantageously being attached at least partially detachably as a cover part. For example, a closure part is inserted into the cover part, e.g. screwed in with a thread, fixed with bayonet closure parts, snapped in or pressed in. The cover part, e.g. in the area of the closure part, is preferably designed or attached in such a way that it can react to volume changes in the PCM material. The entire storage block 3 can be positioned, for example, standing on or in a stable base 5 or lying on support struts or the like.

How Fig. 1B shows enlarged, the line sections 23 are inserted into depressions 13 in the peripheral walls 12 of the hollow profile bars 10 and are connected to one another via the intermediate pieces, for example curved sections, and are fluidically connected at their inlet ends to the inlet section 21 and at their outlet ends to the outlet section 22. The PCM material filled into the cavities 11 of the hollow profile bars 10, which are tightly sealed all around and also at the front, stores heat latently at a certain transformation temperature as a result of a phase change or absorbs heat latently, ie without (significantly) changing its temperature, and can also release heat again without a change in temperature, as for example in the inlet The threshold temperature at which the phase transformation or heat storage and heat release takes place without a change in temperature depends on the type of PCM material and is set, for example, in a temperature range between 35 °C and 80 °C that is suitable for keeping a constant water temperature within the scope of its storage capacity. In connection with a hot water tank heated by solar energy, it is advantageous to select one or more PCM materials with a threshold temperature in the range between 55 °C and 80 °C.

The hollow profile bars 10 are made of a material with good heat conduction, in particular metal, preferably aluminum, and have, on the whole, advantageously polygonal, preferably rectangular or square, or, for example, hexagonal or triangular external cross-sections, with the exception of small deviations such as holding elements and the recesses 13. The recesses 13 are formed in the wall sections of the hollow profile bars 10 which are closely spaced in pairs (directly or indirectly via a contact layer which transfers heat well) opposite one another (cf. Fig. 2A ). The line sections 23, which are adapted in cross-section and are therefore also rounded and circular in this case, are inserted tightly into the rounded, in this case semi-circular, recesses 13 in order to produce good heat conduction from the fluid via the line wall, possibly the contact layer, and the peripheral wall 12 of the hollow profile bars 10 to the PCM material. It is advantageous to insert a sealing material or adhesive material with good heat conduction in the transition area between the peripheral surfaces of the line sections 23 and the recesses 13 in order to prevent moisture from accumulating. This also makes it possible to avoid negative influences from electrochemical potentials between different metals of the line sections 23 and the hollow profile bars 10, for example if the line sections 23 or lines 20 are made of copper and the hollow profile bars 10 are made of aluminum. However, the hollow profile bars 10 and the lines 20 can also be made of the same or similar metals, which in any case are good heat conductors.

The hollow profile bars 10 lie closely together with the flat wall sections a/b, c/d of their peripheral wall 12 along their adjacent sides, directly or indirectly via a contact layer, with good heat conduction, and form with their opposing pairs of complementary recesses 13 the receptacles for the associated line sections 23, which enclose them completely in cross-section (apart from a gap that cannot be completely avoided in practice) if necessary together with the contact layer. In a plane lying in the x-direction and y-direction and perpendicular to the longitudinal extension z, several hollow profile bars 10, at least two in the x-direction and at least two in the y-direction, are arranged next to one another in rows and columns, so that the bundle-like storage block 3 is formed. The storage block 3 can be connected to a fluid reservoir, in particular a hot water tank, for supplying or discharging the fluid to be tempered, in particular water, via the inlet section 21 and the outlet section 22. The input section or possibly several input sections 21 and/or the output section or sections 22 can be arranged protruding from the front or one or more sides of a storage block 3, so that a simple connection option is provided.

Storage blocks 3 can be constructed in different lengths L in the z-direction and widths or thicknesses in the x- and y-directions. Storage blocks 3 can thus be provided which, in total, result in a cavity volume of the cavities 11 with the filled PCM material that is appropriate for the respective heat storage purpose and thus an appropriate storage capacity. The cross-section of the cavities 11 of the individual hollow profile bars 10 and the thickness of the peripheral wall 12 can also be selected appropriately, whereby the width or thickness of the individual hollow profile bars 10 can be in the range between 1 cm and 10 cm, for example between 3 cm and 5 or 6 cm or 8 cm, and the thickness of the peripheral wall 12 can be in the mm range, for example between 0.5 and 3 mm. In addition, the hollow profile bars 10, as shown, have rib-like structures projecting into the cavity 11 to assist heat transfer.

In order to adapt threshold temperatures to the temperature ranges of the different temperature layers within a hot water tank or several hot water tanks, several storage blocks 3 of the structure described above can be combined, which are filled with different PCM material, for example with threshold temperatures in the range of 40 °C, 50 °C, 60 °C and 70 °C or 80 °C. Alternatively, PCM materials with different threshold temperatures can also be filled into the cavities 11 of different hollow profile bars 10 within a storage block 3, wherein the line arrangement 2 is provided with associated inlet sections 21, outlet sections 22 and line sections 23 as well as adapted intermediate pieces.

Another design variant or possibility of adaptation to different heat storage capacities arises by combining several storage blocks 3 to form a larger heat storage unit 1, wherein, for example, several storage blocks 3 are arranged next to one another or in a row in the longitudinal direction.

Another or additional variation option is provided by combining individual line sections within a storage block by fixed or controlled parallel and/or series connection (e.g. via valves) by means of appropriate arrangement or design of the intermediate pieces.

The bundles of hollow profile bars 10 are held together, for example, by means of circumferential retaining straps or a casing. In addition, the heat storage unit 1 or a storage block 3 can be surrounded by a heat-insulating casing, such as a thermal external insulation made of four flat, plate-shaped thermal insulation plates, which are attached to the Storage block 3 can be attached detachably. If a heat storage unit 1 comprises hollow profile bars 10 into which PCM materials with different threshold temperatures are filled, those with a lower threshold temperature can be arranged more on the outside and those with a higher threshold temperature more on the inside in order to keep heat transfer to the environment as low as possible.

The structure of the heat storage unit 1 with a storage block 3, which is designed as a bundle of several hollow profiles or hollow profile rods 10 arranged next to one another in rows and columns (in the x and y directions), results in a spatially compact design, whereby the heat exchange between the heat transfer fluid flowing through the line sections 23 and the PCM material takes place in the storage block 3, for which purpose the closest possible contact between the hollow profile rods 10 and the line sections 23, resulting in the most effective heat transfer possible, is essential for the efficient heat exchange and thus operation of the heat storage unit 1. The Fig. 1A, 1B shown structure of the memory block 3, in particular with the Fig. 2A and 2B The hollow profiles shown in cross-section result in a clear, precise arrangement with simple assembly steps and a close, good heat-conducting arrangement between adjacent wall sections a/b or c/d and the pipe sections 23 carrying the heat-transporting fluid.

How Fig. 2A based on a bundle of four hollow profile bars 10 (or hollow profiles) in a cross-sectional plane, two in the x-direction and two in the y-direction, the hollow profiles 10 consist largely (ignoring smaller contours in their peripheral wall 12) of square hollow profiles, in this case with a square cross-section. A similar structure with rectangular hollow profiles would also be possible. In each of the four wall sections a, b, c and d, there is a semicircular depression 13 in the middle with respect to the extension in the cross-sectional plane, which is complemented by an opposite depression of an immediately adjacent hollow profile to form a complete free space with a circular cross-section, wherein the wall sections of adjacent hollow profiles running in the direction of the row are aligned with each other or lie in the same plane. During assembly, before the adjacent hollow profiles are completely assembled, respective line sections 23 are inserted into the resulting circular free spaces, which are then completely enclosed by the adjacent hollow profiles in close contact after they have been placed against each other, as can be seen from Fig. 1B visible.

In order to bring the individual hollow profiles 10 into close contact with one another in a row direction, in this case in the x-direction, simply and clearly and aligned with one another in the manner described above, the two wall sections a, b of each hollow profile 10 oriented at right angles to the row direction x are provided with holding elements near their profile edge K1 that merges into the same profile side, which consist of a hanging groove 14 on one wall section a and a holding web 15 on the other wall section b. The hanging groove 14 and the holding web 15 of two hollow profiles 10 adjacent in the row direction x thus form complementary interlocking holding elements of a holding arrangement 16.

The holding elements in the form of the hanging groove 14 on the one hand and the holding web 15 on the other hand preferably run continuously in the z-direction over the entire length of the hollow profile 10 (although interruptions are not excluded, they would be less favorable for the profile formation) and are designed in such a way that they can be joined together in a combination of a translational movement and a rotational movement, whereby the two wall sections a, b are initially placed one inside the other in an oblique orientation to one another in the cross-sectional plane and then pivoted against one another in a hinge-like manner by a pivoting movement until they come into contact with their wall sections a, b flatly, after a respective line section 23 has been inserted into the circular free space between the relevant recesses 13. In order to be able to bring about the joining in the initially oblique orientation of the two hollow profiles to be arranged in a row, the hollow profile provided with the holding web 15 is between the holding web 15 and its (imaginary) adjacent profile edge are bevelled by an angle α with respect to the further (in cross-section) straight course of the wall section b, so that a recess bb is formed between the wall section a provided with the hanging groove 14 and the bevel. This means that the hollow profile having the retaining web 15 with its wall section b can be inserted unhindered into the hanging groove 14 with the retaining web 15 while orientated at an angle to the adjacent wall section a of the hollow profile having the hanging groove 14 and can then be moved with its wall section b into flat contact with the wall section a while pivoting.

As from Fig. 2B As can also be seen, the retaining web 15, which protrudes from the wall section b with a projection part 151, is provided with a retaining lug 150 which is directed parallel to the wall section b and points outwards (in the direction of the profile edge). The hanging groove 14 is provided with a retaining edge 140 (in the form of a profile section) directed in the same direction as the adjoining wall section a, pointing away from the profile edge K1, which limits the groove opening to the groove space formed by the hanging groove 14 to a clear width w that is slightly larger than the thickness s of the projection part 151 of the holding web 15 running parallel to the wall section a or b. The length l of the retaining lug 150 running parallel to the wall section a or b (in the aligned state) is approximately as long (or slightly shorter) as the retaining edge 150 of the hanging groove 14 pointing in the same direction. The groove depth t (between the outside of the wall section a and the groove base) is slightly larger than the depth-direction extension of the projection part 151 and the sum of the thickness of the projection part s and the length of the retaining lug I is slightly smaller than the extension of the groove space in the direction of the wall section a behind the retaining edge 140. Furthermore, the distance d of the edge of the projection part 151 pointing towards the profile edge is approximately as large as the distance between the profile edge K1 and the edge of the retaining edge 140 which limits the clear width of the groove opening, so that in the assembled state of the lined-up hollow profiles 10, the lines running in the lined-up direction (in this case x-direction) Wall sections c, d are aligned with one another in the same plane (wherein the hollow profile bars 10 each have the same cross-sectional contour). The holding elements, hanging groove 14 and holding web 15, with their above-mentioned components, are coordinated with one another in such a way that the adjacent hollow profiles 10 lined up next to one another with their wall sections a, b facing one another lie closely against one another, which is supported by the pivoting-in process. In the assembled state, the profiles cannot be pulled apart in the direction of the row because the holding lug 150 engages behind the holding edge 140. In order to fit the holding elements together without hindrance, the projection part 151 of the holding web 15 is also rounded towards the bottom of the groove on its side remote from the holding lug 150. The pivoting-in process is also supported by the fact that the holding element arrangement 16 and the recess bb in the above-mentioned design are located close to one profile edge K1 and away from the other profile edge K2 delimiting the same wall section.

If several hollow profiles 10 are lined up in a layer in the desired width of the storage block 3 (e.g. in the x direction) as described above, the next layer can be formed from hollow profiles 10 lined up in a corresponding manner and placed on the previous layer (e.g. in the y direction) in such a way that the end wall sections c, d of the layers placed on top of one another are flush with one another in one plane. If enough layers of lined up hollow profiles in the desired number or thickness of the storage block 3 are placed on top of one another, the bundle can be tied together with bands, such as Velcro bands, and then covered with heat insulation. For this purpose, the storage block can be inserted into an adapted base 5 which has a receiving space adapted to the outer contour of the storage block 3. Similarly, an adapted cap made of heat-insulating material can be placed on the upper end section of the storage block 3, through which connecting lines can be guided. Finally, the outer sides of the storage block 3 can be covered with heat-insulating material.

The illustrated structure of the heat storage unit 1 with at least one storage block 3 results in a compact, easy-to-handle design that can also be advantageously adapted to different spatial conditions.

Claims (15)

1. Heat storage unit (1) having at least one storage block (3) which is designed as a bundle of a plurality of closed hollow chambers made from hollow profiles, which chambers extend in parallel with one another, extend longitudinally in the z-direction, and are each filled with PCM material (4),

   - in the cross-sectional plane extended in the x-y direction, both in the x-direction and in the y-direction of the storage block (3), at least two hollow chambers having wall portions (a, b, c, d) of their peripheral walls (12) being arranged so as to closely abut one another directly over the surface or indirectly via a thin, highly thermally conductive contact layer,

   - the peripheral walls (12) being provided with indentations (13) extending over their entire length in the longitudinal direction at least in some of their wall portions (a, b) which are opposite one another in pairs,

   - the indentations (13) in the peripheral walls (12) of two adjacent hollow chambers complementing one another in cross-section to form a closed, in particular circular, ring, and

   - a line arrangement (2) being guided through the storage block (3) so as to convey heat-transporting fluid, which line arrangement has at least one line (20) comprising a plurality of line portions (23), which are connected in the indentations (13) in direct contact or in contact established via a heat-conducting means to each of the adjoining regions of the peripheral wall (12) and to the PCM material (4) thereon,

   characterized
   in that the wall portions (a, b) opposite one another in pairs are provided with respect to only one arrangement direction (x or y) with a retaining element arrangement (16) over their entire length, which arrangement has, in one wall portion (a), a hook-in groove (14) having a groove recess, groove opening and retaining edge (140) and, in the other wall portion (b), a retaining projection (15) which can be inserted laterally into the hook-in groove (14) at right angles to the z-direction and has a projection part (151) and a retaining lug (150), which engages behind the retaining edge (140) in the assembled state, it being possible for the hook-in groove (14) and the retaining projection (15) to be shaped and dimensioned in such a way that they can be fitted into one another in the arrangement direction (x or y) and to such an extent that the wall portions (a, b) opposite one another in pairs come into contact with one another directly or indirectly via the contact layer which may be located therebetween.
2. Heat storage unit according to claim 1,
   characterized

   in that the hollow chambers, formed from hollow profiles, with their peripheral wall (12) each have the same, substantially rectangular or square cross section comprising wall portions (c, d; a, b) which are plane-parallel to the x-z plane and to the y-z plane, except for the indentations (13) and retaining element arrangements (16) and possibly a recessed edge region next to the retaining projection (15), and

   in that the hollow chambers lined up in the x-direction with their two wall portions (c, d) oriented in the x-z plane and the hollow chambers lined up in the y-direction with their two wall portions (a, b) oriented in the y-z plane are flush with one another.
3. Heat storage unit according to claim 2,
   characterized
   in that in each hollow profile only the wall portion (y-z plane or x-z plane) extended at right angles to an arrangement direction (x or y) is provided with a hook-in groove (14) and only the other wall portion (y-z plane or x-z plane) extended at right angles to this arrangement direction (x or y) is provided with a retaining projection (15), the hook-in groove (14) and the retaining projection (15) of the hollow profile being spaced apart at the same distance (d) with respect to the same wall portion (x-z plane or y-z plane) extended in the arrangement direction (x or y), so that the latter wall portions lie flush in a common plane in the arrangement direction (x or y) of adjacent hollow profiles in the assembled state.
4. Heat storage unit according to claim 3, insofar as it relates to claim 2, characterized

   in that the wall portion (a), in which the hook-in groove (14) is arranged, is flat except for the groove opening of a clear opening width (w) and at least one indentation (13) and is otherwise extended as far as the profile edges which delimit it, extend in the z-direction and which may be somewhat rounded,

   in that the clear opening width (w) of the hook-in groove (14) is at most one-sixth or one-eighth of the width of the relevant wall portion (a) and

   in that the retaining groove (14) is arranged closer to one of these two profile edges (K1) than to the other profile edge (K2) with respect to the center of its groove opening, in particular in the outer edge-side quarter of this wall portion (a), the distance (d) between the edge-side opening edge of the retaining groove (14) and the near profile edge (K1) corresponding to the distance (d) between the face of the projection part of the retaining projection (15), which face is adjacent to the opening edge, and the near profile edge (K1), so that the wall portions (c, d) of adjacent hollow profiles, which wall portions are oriented at right angles to these wall portions (a, b), are flush with one another.
5. Heat storage unit according to claim 4,
   characterized
   in that the wall portion (b) provided with the retaining projection (15) is provided in the region between the edge-side attachment point of the projection part (151) and the near profile edge (K1) of this hollow profile with a recess (bb) which widens outward toward the edge region, in particular a bevel at an angle (α), relative to its contact plane.
6. Heat storage unit according to claim 5,
   characterized
   in that the clear opening width (w) of the groove opening is greater than the thickness (s), measured in the same direction, of the projection part (151) of the retaining projection (15) but smaller than the sum of the thickness (s) of the projection part (151) and the length (l) of the retaining lug (150) projecting in the same direction and engaging behind the retaining edge (140) in the assembled state, which lug is at most as long as the width of the retaining edge (140) in this direction, and in that the groove depth (t) is greater than the length of the projection part (151) with the retaining lug in the depth direction of the hook-in groove (14).
7. Heat storage unit according to any of the preceding claims,
   characterized
   in that the peripheral walls (12) of the hollow chambers are made of metal with good thermal conductivity, in particular aluminum, and at least the line portions (23) of the line arrangement (2) are made of metal, in particular copper.
8. Heat storage unit according to any of the preceding claims,
   characterized
   in that in each wall portion of each polygonal hollow profile, in particular rectangular or square square hollow profile, an indentation (13) is arranged centrally with respect to the cross-sectional width of the wall portion.
9. Heat storage unit according to any of the preceding claims,
   characterized
   in that the hollow chambers are tightly closed on the end face on both ends with a lid part, in particular an upper lid part in the erected state being provided with an openable closure part.
10. Heat storage unit according to any of the preceding claims,
    characterized
    in that the line arrangement (2) has at least one inlet portion (21) and at least one outlet portion (22) for connection to a storage water heater.
11. Heat storage unit according to any of the preceding claims,
    characterized

    in that the same PCM material is filled into each of the hollow chambers of a storage block (3), or

    in that at least two groups of hollow chambers are formed within a storage block (3), into which PCM materials with different conversion temperatures are filled, different heat circuits being assigned to the different groups by means of the line arrangement (2).
12. Heat storage unit according to any of the preceding claims,
    characterized
    in that the bundle of hollow chambers of a storage block (3) is formed from a plurality of hollow chambers arranged linearly in a row in an arrangement direction (x-direction or y-direction) and held together by means of the retaining element arrangement (16) to form a hollow chamber layer, and a plurality of layers placed against one another with their two end-face wall portions flush with one another in one plane.
13. Heat storage unit according to any of the preceding claims,
    characterized

    in that the bundle of hollow chambers of a storage block (3) is held together by means of at least one folded-over, tensioned strap,

    in that the bundle of hollow chambers of a storage block (3) is accommodated, in particular inserted, with an end-face lower portion in a thermally insulating base (5), and

    in that the bundle is encased on its periphery and on its upper face by an outer insulation (4) of, in particular, planar thermal insulation material.
14. Method for constructing a heat storage unit according to any of the preceding claims,
    characterized

    in that individual hollow chambers, which are formed with rectangular or square hollow profiles of square cross-section, are tightly joined together in an arrangement direction (x or y) to form a layer of a plurality of adjacent hollow chambers, by means of retaining element arrangements (16) which are formed on the outside of their peripheral walls (12) and have mutually complementary retaining elements extending longitudinally in the z-direction, line portions (23) being inserted into indentations (13) between wall portions (a, b) of the hollow chambers,

    in that a plurality of layers of joined hollow chambers are stacked on top of one another with their end-face wall portions flush at right angles to the arrangement direction,

    in that the layers stacked on top of one another are held together to form a bundle by means of at least one folded-over strap and/or by means of a cap placed on the top of at least one end-face portion of the bundle and/or a base (5) fitted on the bottom,

    in that the line portions are connected via connecting pieces to form a line arrangement and

    in that the storage block (3) is encased on the periphery before or after the cap and/or the base is fitted by means of heat-insulating material.
15. Method according to claim 14,
    characterized
    in that there are also indentations between the layers in the wall portions of the hollow profiles, into which indentations line portions (23) of the line arrangement are inserted.

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