Adsorption refrigeration machine with metal-organic framework compounds as adsorption material and production method

Abstract

The invention relates to an adsorption refrigeration machine (1) comprising a process chamber (2) which can be supplied with refrigerant and an adsorber (4) which is accommodated in the process chamber (2), wherein the adsorber (4) comprises a tube (5) for a heat transfer medium to flow through and an adsorbent (8) which encases the tube, wherein refrigerant can be adsorbed or desorbed by the adsorbent (8) in accordance with the physical state of the refrigerant in the process chamber (2), wherein the adsorbent (8) comprises casing elements (9) arranged in a row in the longitudinal extent (6) of the tube (5), wherein each casing element (9) has an adsorption material (13) with a predominant proportion of metal-organic framework compounds.

Description

[0001] ADSORPTION CHILLER WITH ORGANIC METALLOCUM FRAMEWORK COMPOUNDS AS ADSORPTION MATERIAL

[0002] AND MANUFACTURING PROCESSES

[0003] The invention relates to an adsorption refrigeration machine comprising at least one or preferably two adsorbers or desorbers, wherein each adsorber or desorber comprises a tube and an adsorbent encasing the tube, wherein the adsorbent comprises jacket elements, said jacket elements having an adsorption material with a predominant proportion of metal-organic frameworks (MOF). Alternatively, such jacket elements can also be used in an adsorption heat pump, or the invention analogously also relates to an adsorption heat pump, since the components used therein can be designed in the same way as in an adsorption refrigeration machine, although the physico-chemical processes can be applied in a modified manner. In any event, the term adsorption refrigeration machine is to be interpreted broadly in this sense, since it is used only as an example and thus in the broadest sense for the technical field of machines with adsorbers orDesorbem can be understood.

[0004] Adsorption chillers can be used to utilize thermal energy in the low-temperature range below 100°C. They can utilize the thermal energy of a medium with an exemplary temperature range of 55°C to 95°C with a thermal efficiency of approximately 0.6 through an energy conversion process. This allows them to provide, for example, chilled water with a temperature in the range of 8°C to 18°C, which can be used for air conditioning buildings. For example, waste heat from heating or chemical plants or even heat from solar energy systems can be used to provide the thermal energy.

[0005] The adsorption principle used in adsorption chillers is a phase boundary phenomenon, which is why solids with a large internal surface area are usually preferred as adsorption materials. Such solids known from the state of the art for adsorption chillers include silica gel, aluminum oxide gel, activated carbon, or zeolites. Due to their large internal surface area, these solids ensure sufficient adsorption capacity and can thus bind significant amounts of a refrigerant, such as water or water vapor, by adsorption. In addition to the adsorption properties of the adsorbent, its desorption properties are also crucial. Since silica gel, for example, releases adsorbed water even at low desorption temperatures, it is particularly well suited for use in

[0006] Suitable for adsorption refrigeration systems.

[0007] The aforementioned energy conversion process of an adsorption chiller is discontinuous. Accordingly, an adsorption chiller comprises at least one, or in the present exemplary application, two, adsorbers and desorbers, by means of which the adsorption and desorption processes are alternately implemented. The refrigerant adsorbed or desorbed by the respective adsorber or desorber can be, for example, water or water with additives or, for example, alcohol. Water or cooling water can be used as the heat transfer medium used to supply heat to the adsorption chiller or to remove heat from it, i.e., for example, equally for use in the condenser, evaporator, and both adsorbers and desorbers.It is also possible to use a different heat transfer medium as an alternative, such as a direct coupling of the absorption chiller with a solar system.

[0008] During operation of the adsorption chiller, for example, two process pairs can run in parallel. The first process pair is the evaporation of the refrigerant in the evaporator and the adsorption of the resulting water vapor in the adsorber. The first of the two adsorbers or desorbers acts as the adsorber. This process pair is implemented in the low-pressure section of an adsorption chiller and enables the provision of cold water using a cooling distribution system coupled to the evaporator. The second process pair is formed by the desorption of the refrigerant previously bound or adsorbed on the adsorber or desorber in the desorber, followed by condensation of the resulting water vapor in the condenser. A second of the two adsorbers or desorbers acts as the desorber. This process pair is implemented in the high-pressure section of an adsorption chiller.This process control allows for quasi-continuous discontinuous operation despite the saturation characteristics of the adsorption and desorption processes in the two adsorbers and desorbers, respectively, because the adsorption and desorption chambers are alternately connected in the two process pairs. The two adsorbers and desorbers, the condenser, and the evaporator can each be accommodated in specially designed chambers or process chambers, particularly in hollow cylindrical chambers, in order to ensure the pressures or negative pressures required for the adsorption process compared to atmospheric ambient pressure. Switching between the process control modes can be controlled by means of two-way or multi-way valves passively controlled by differential pressures, or by actively controlled two-way or multi-way valves.be regulated so that as soon as the adsorbent is saturated with the refrigerant vapor, the heating and cooling circuit is switched between the heat exchangers of the adsorber and desorber, so that the adsorbent of the adsorber saturated with refrigerant is converted into the desorption state and the adsorbent of the desorber is converted into the adsorption state.

[0009] According to the previous description, an adsorption chiller comprises at least one adsorber or desorber, or possibly two adsorbers or desorbers, to ensure its proper functioning. For the sake of simplicity, the term "adsorber" will be used synonymously below for the adsorber or desorber system component of an adsorption chiller, since it is now clear that refrigerant can be adsorbed by such an adsorber and, with appropriate process control, also desorbed.

[0010] The efficiency and cost-effectiveness of such an adsorption chiller's operation and manufacture are largely determined by the adsorbent used in the adsorber and the corresponding adsorber design. The prior art, such as document DE 38 08 653 C2, primarily uses silica gel or alternative working materials such as zeolite or activated carbon. The use of these working materials restricts the design of the adsorber for an adsorption chiller and, in conjunction with this, further limits its efficiency and performance, and thus its cost-effectiveness.

[0011] The object of the present invention was to overcome the disadvantages of the prior art and to provide an adsorption chiller, a method for producing an adsorber for an adsorption chiller and a method for producing a jacket element for encasing a tube of the adsorber, by means of which the manufacturability and operation of an adsorption chiller are improved.

[0012] The adsorption refrigeration machine according to the invention comprises a process chamber which can be charged with refrigerant and an adsorber accommodated in the process chamber, wherein the adsorber comprises a tube for the flow through of a heat transfer medium and an adsorbent which surrounds the tube at least in sections with respect to a longitudinal extent of the tube and completely with respect to a circumference of the tube, wherein refrigerant can be adsorbed or desorbed by the adsorbent in the process chamber according to its physical state.

[0013] The adsorption chiller is further characterized in that the adsorbent comprises jacket elements or casing elements arranged in a row along the longitudinal extent of the tube, wherein each jacket element comprises an adsorption material with a predominant proportion, in terms of mass fraction, of metal-organic framework compounds.

[0014] In this context, the adsorbent itself does not necessarily have to have a predominant proportion of metal-organic framework compounds, but it is relevant in the sense of the invention that the adsorption material, which forms the component functional for the adsorber, has a predominant proportion of metal-organic framework compounds.

[0015] The adsorbent can be applied around the pipe in a variety of ways. For example, it is conceivable for the adsorbent to be assembled from semi-cylindrical shells as casing elements, with two semi-cylindrical shells combined to form a cylindrical casing element, so that the pipe is ultimately essentially completely encased in the circumferential direction, even if this casing is composed of two shells. Similarly or alternatively, it can also be provided that the casing elements are disc-shaped, with these disc-shaped elements being able to be pushed onto the pipe, so that the pipe is completely encased with the adsorbent. In any case, the invention is not restricted to any specific shape of the casing element.In this sense, it is also conceivable that a jacket element can be penetrated by several tubes and has a shape or outer contour that is advantageous for its adsorption properties.

[0016] An advantage here is that the shell elements can have a large internal surface area of ​​up to over 4500 m2 / g due to the predominant proportion of metal-organic framework compounds in the adsorption material. This results in a particularly high proportion of refrigerant being adsorbable and equally desorbed per volume of adsorbent, which has a particularly advantageous effect on the convertible adsorption and desorption enthalpy per volume of adsorbent. As a result, the adsorber of an adsorption chiller can be constructed particularly compactly, as its adsorption kinetics are improved.Furthermore, metal-organic frameworks are particularly resistant to degradation of their adsorption capacity, especially when using water or a water-alcohol mixture as a refrigerant, which is particularly advantageous with regard to the system efficiency of the adsorption chiller over its operating life and its service life. Likewise, shell elements with a predominant proportion of metal-organic frameworks have proven particularly resistant and long-term stable against the thermal stresses encountered in adsorption chillers using water or a water-alcohol mixture as a refrigerant.

[0017] Another advantageous embodiment is one in which each casing element comprises a stabilizing supporting structure, wherein the adsorption material is permeated by the supporting structure, or the supporting structure is formed by the adsorption material. It is also possible for the adsorption material to be molded onto the supporting structure, or for the adsorption material to be introduced into the supporting structure and, if necessary, also applied around the supporting structure, in order to then be pressed together with the supporting structure to form the casing element, thus providing a dimensionally stable casing element comprising the adsorption material and the supporting structure.

[0018] The supporting structure can, for example, be designed as a grid or mesh penetrating the adsorption material. In this sense, a supporting structure is understood to be a vapor-permeable and / or gas-permeable support structure which, among other things, has a shape-stabilizing effect on the adsorption material. Alternatively, it is also conceivably advantageous if the adsorption material is enclosed or formed by the supporting structure in a mesh-like manner. This can improve the dimensional stability of the adsorption material in conjunction with the stabilizing supporting structure, so that the adsorption medium as a whole, and subsequently each shell element, is stabilized or dimensionally stabilized in order to be able to permanently withstand the thermal, physical, or chemical stresses of the process in the adsorber of the adsorption chiller.

[0019] Furthermore, it can be provided that the supporting structure is made of a heat-conducting material, wherein the heat-conducting material is in particular a metallic material, specifically an aluminum, copper, steel, or iron alloy. Alternatively, it can also be provided that the supporting structure is formed from individual and non-connected threads, fibers, or flakes, so that a shape-stabilizing effect of the supporting structure only develops in interaction with the adsorption material.

[0020] In this way, the transfer efficiency of the adsorption and desorption enthalpy, or the heat transfer within each shell element, is improved, and subsequently the heat transfer between the adsorbent and the tube is improved, since the heat transfer medium flows through the tube and thus interacts with the adsorbent as a heat sink or heat source in each process step of the adsorption chiller. In particular, in this context, it can also be provided that the tube is made of a metallic material, specifically an aluminum, copper, steel, or iron alloy.

[0021] In this context, it can also be provided that the adsorption material, which comprises a predominant proportion of organometallic compounds, also comprises a binder that is optionally thermally conductive. Furthermore, for the purpose described above, the adsorption material can alternatively or additionally also comprise powder, threads, flakes, or fibers of another material with high thermal conductivity or with thermal conductivity in the range of metallic materials. Furthermore, it can be provided that the supporting structure has a receiving area, wherein the receiving area of ​​the supporting structure is designed to complement the shape of the circumference of the pipe.

[0022] This results in a close or direct, preferably form-fitting and contacting fit of the receiving area of ​​the supporting structure and thus of the respective casing element against the pipe, thereby improving heat transfer between the supporting structure or the entire casing element and the pipe. For example, this receiving area can be formed by another pipe or by a pipe section, whereby the receiving area is in any case formed as a partial section of the supporting structure or is in any case thermally conductively connected to the supporting structure.

[0023] In particular, in this context, it can advantageously be provided that a thermally conductive paste, a thermally conductive adhesive or a thermally conductive coating is applied to the pipe or to the surface of the receiving area of ​​the supporting structure or the casing element facing the pipe between the respective casing elements and the pipe in order to further improve the heat transfer between the respective casing element and the pipe.

[0024] In particular, it can be advantageous if each jacket element is designed as a sleeve-shaped jacket element that fully extends around the pipe, with each jacket element having an opening so that the jacket elements can be pushed onto the pipe in the direction of its longitudinal extension. It can be provided that the jacket elements can be easily pushed onto the pipe, i.e., for example, that the receiving area is oversized relative to the outer diameter of the pipe. Subsequently, the pipe can be expanded, for example, to fix the position of the jacket elements surrounding this pipe.

[0025] It can also be advantageous for the supporting structure to comprise a grid or grid network penetrating the adsorption material, wherein the grid network forms a vapor-permeable and / or gas-permeable support structure that has a shape-stabilizing effect on the adsorption material. In this context, it can be provided that the receiving area is formed from a hollow-cylindrical tube section with a wall having a wall thickness, wherein the grid network is connected to the wall, in particular is connected in a thermally conductive manner, wherein an overlap of the wall with the grid network is formed over a predominant part of the wall thickness or on an end face of the wall. In this sense, the receiving area is formed by an inner surface of the hollow-cylindrical tube section.

[0026] In this regard, it can be advantageous for the grid to be pressed into the wall, wherein the receiving area is preferably formed from an aluminum alloy and wherein the grid is specifically formed from a metallic alloy, in particular an aluminum alloy. In this context, it can further be provided that the hollow cylindrical pipe section has a flange or a flange-shaped edge or a bead in the receiving area. This can be formed by appropriately pressing the grid into the wall and can serve to enlarge the receiving area for positioning the jacket element on the pipe in order to subsequently improve the heat transfer between these two components.Likewise, a relatively increased surface roughness can be provided in an area of ​​the wall that does not have a bead, so that adsorption material adheres to this area and accordingly contributes to the adsorption capacity of the casing element, with the grid covering this area of ​​the wall. This possible design of the casing element can be combined with any other possible designs, in particular with those mentioned in the subsequent description of Fig. 4.

[0027] The adsorber is easy to manufacture thanks to the possible designs described above. For example, the shell elements can be mass-produced as disc-shaped elements or as hollow-cylindrical elements or multi-part shell elements with an opening, for example by punching or cutting them out of plates as a starting product or alternatively by manufacturing them as individual elements in specially designed molds. For example, it is conceivably advantageous for a supporting structure with adsorption material to be pressed or joined together in a specially designed mold to produce a shell element. These shell elements can then be pushed onto the adsorber tube or arranged around the adsorber tube. Depending on the selection of the diameter of the opening, a press fit on the tube can also be adjusted if necessary.This can be implemented, for example, by thermal shrinking or similar processes. In this context, it can also be advantageous if the opening in the casing element has a receiving area of ​​the supporting structure in the form of the opening, wherein the receiving area is in turn formed as a partial section of the supporting structure and from the same material as the supporting structure. For example, a lattice-shaped area of ​​the supporting structure can be designed to support or stabilize the adsorption material, and the receiving area of ​​the supporting structure can be designed as a metallic complementary element in the form of the opening, wherein the complementary element is coupled to the lattice-shaped area of ​​the supporting structure, in particular in a heat-conducting manner, and wherein the complementary element is designed to be shape-complementary to the circumference of the pipe in order to be able to establish a positive connection or at least a heat-conducting connection with the pipe.

[0028] According to an advantageous development, it can be provided that a spacer is provided between two jacket elements that are closest in the longitudinal extension of the tube, wherein the spacer is made of a porous and / or gas-permeable material. The spacer can, for example, also be formed as a partial region of the jacket element. For example, it is conceivable that a jacket element can have structures protruding from its surface, such as webs or knobs. Likewise and optionally alternatively, it can also be provided that a jacket element has layers or coatings with adsorption material at edge regions that have a reduced density compared to the adsorption material inside the jacket element, so that these layers in the edge regions act as spacers between the respective adsorption material inside the jacket elements that are closest to one another.Likewise, and optionally alternatively, it can also be provided that a jacket element has a smaller thickness in an outer region relative to the pipe than in an inner region, so that a bevel is created. This ensures that outer regions of the jacket element are vapor-permeable, so that the adsorption and diffusion properties of the jacket element or, in particular, of an adsorbent with adjacent jacket elements are improved. In this context, the thickness extension is understood to mean that extension - 10 - of the jacket element that extends along a central axis of the hollow-cylindrical pipe section.

[0029] The advantage of this is that the adsorber surface is increased in addition to the inner surface of the shell element. This is due to the fact that refrigerant molecules diffuse comparatively more easily through the porous and / or gas-permeable spacer than through the adsorption material itself.

[0030] According to a particular embodiment, it is possible for the spacer to have the same cross-section as a jacket element and a thickness from a thickness range comprising 0.05 mm to 2 mm.

[0031] This thickness range is chosen because water or a water-alcohol mixture can preferably be used as the refrigerant, whereby the thickness of the spacer is thus chosen to be large enough to enable the diffusion of the refrigerant at a high kinetic level and whereby the thickness of the spacer is thus chosen to be small enough to provide the jacket elements and thus the adsorption material with the greatest possible volume fraction of the adsorbent.

[0032] Furthermore, it can be provided that the spacer is applied as a coating or as an additional layer to each of the casing elements of the adsorbent, wherein the spacer is formed, in particular, from metal foam. Alternatively, it can also be provided that a spacer is formed as an independent component of the adsorber and that a spacer is provided between each two adjacent casing elements.

[0033] In any case, it can be particularly advantageous if, by means of a coating or an additional layer of metal foam, a spacer that is as thin as possible can be formed on a respective jacket element or positioned between two adjacent jacket elements. Furthermore, it is advantageous that a metal foam has high thermal conductivity while at the same time being highly porous and gas permeable. These properties further enhance the previously described advantages of a spacer. Alternatively or additionally, it can also be provided that a distance is established between two adjacent jacket elements even without a spacer. It can namely be provided that the jacket elements are first pushed onto the pipe, with the pipe then being expanded in order to hold the jacket elements in position on the pipe.As a result of this expansion, a distance may arise between the sheath elements which would make the provision of spacers between two sheath elements located closest to each other obsolete.

[0034] Furthermore, it can be provided that the adsorbent is produced by pressing together, at least in sections with respect to the longitudinal extent of the tube, casing elements and spacers arranged in a row along the longitudinal extent of the tube, so that a density of the adsorbent material in the adsorbent or in the casing element has a higher value than 0.2 g / cm 3 , in particular a value from a range of values ​​comprising 0.5 g / cm 3 up to 2.2 g / cm 3 has.

[0035] In this context, it can be provided that the shell elements are particularly disc-shaped or hollow-cylindrical, which significantly simplifies their manufacture and the assembly of the adsorber. By pressing the shell elements and the spacers between them together, or by compressing and squeezing them, the density of the shell elements or the density of the adsorption material, in particular the metal-organic framework compounds, is increased, which improves the adsorption and desorption properties of the adsorbent. This allows the adsorber to operate longer in each process step and increases the usable evaporation or condensation enthalpy, thus further improving the efficiency of the adsorption chiller.At the same time, the spacer can be designed in such a way that its density is only slightly increased during compression, and preferably that its porosity and gas permeability remain unaffected. This further increases the adsorption surface of the adsorbent and significantly improves the adsorption kinetics.

[0036] Furthermore, it may be expedient if the casing elements for producing the adsorbent are lined up or stacked in a row directly next to one another with respect to the longitudinal extent of the tube and are pressed or pressed against one another at least in groups with respect to the longitudinal extent of the tube, so that a density of the adsorption material in the adsorbent or in the casing element has a value higher than 0.2 g / cm 3 , in particular a value from a range of values ​​comprising 0.5 g / cm 3 up to 2.2 g / cm 3 has.

[0037] In this context, it can be provided that the shell elements are particularly disc-shaped or hollow-cylindrical, which significantly simplifies their production and the assembly of the adsorber. By pressing the shell elements together or by pressing and squeezing them, their density or the density of the adsorption material, in particular of the metal-organic framework compounds, is increased, which improves the adsorption and desorption properties of the adsorbent. This allows the adsorber to operate for longer in each process step and increases the usable evaporation or condensation enthalpy, so that the efficiency of the adsorption chiller is further improved. The pressing or pressing of the shell elements together can, for example, be carried out once during the production of the adsorbent, with the shell elements possibly beingplastically deformed together with the spacers. Hysteresis of the subsequent expansion of the adsorbent following compression can be neglected, provided the density of the adsorbent remains within its specified value. Alternatively, the adsorbent can also be compressed between two supports, with the supports being fixed to the pipe after compression, so that the adsorbent remains in the compressed state.

[0038] Furthermore, it may be useful if the adsorption material comprises dicarboxylate as organic binder molecules.

[0039] Furthermore, it can also be advantageous to use aluminum fumarates, in particular, as the metal-organic framework compound. Aluminum fumarate is a material belonging to the class of metal-organic frameworks (MOPs), which are crystalline, porous coordination networks. MOFs are produced by arranging metal nodes (here, aluminum oxide) and bridging organic ligands (also called "linkers") in a repeating pattern. Aluminum fumarate exhibits a microporous, narrow pore size distribution. One advantage of Al-MOFs, especially aluminum fumarate, is their high chemical and hydrothermal stability, which makes them ideal for applications where water content or moisture cannot be avoided. Aluminum fumarate exhibits a highly desirable steep s-shaped water sorption isotherm with uptake in a low partial pressure range.Furthermore, aluminum is considered non-toxic and is one of the most abundant (8.3% by weight in the Earth's crust) and therefore the cheapest metal. Fumaric acid (trans-butenedioic acid, CAS 110-17-8) is also a non-toxic chemical used as a food additive. It can be obtained through biologically based fermentation processes.

[0040] A shell element with an adsorption material with a predominant proportion of metal-organic framework compounds can, particularly in connection with the above descriptions, have a thickness in a range comprising 0.1 mm to 4 mm, or in particular comprising 0.4 mm to 1.5 mm. The thickness is understood to be the extension of a shell element in the direction of the longitudinal axis of the tube. These ranges arise primarily due to the necessary mechanical stability of the shell elements and due to the requirements that the adsorbent be composed of shell elements and that the adsorption and desorption, and subsequently, above all, the gas diffusion, must be optimized.

[0041] Furthermore, it may also be advantageous if the casing elements are manufactured as pressed pieces from the supporting structure and the adsorption material pressed into the supporting structure. For example, it is conceivable that a supporting structure is placed in a mold designed for the compression molding of a casing element, so that the adsorption material is further added to the mold, and then the adsorption material is pressed into the supporting structure to form a pressed piece.

[0042] This makes it easy to provide a jacket element that has an adsorption material density higher than 0.2 g / cm 3 , in particular with a value from a range of values ​​comprising 0.5 g / cm 3 up to 2.2 g / cm 3, has.

[0043] According to the invention, a method for producing an adsorber for an adsorption refrigeration machine is further provided, the method comprising the following method steps:

[0044] - Providing a pipe with a longitudinal extension and a circumference, wherein the pipe can be flowed through with heat transfer medium;

[0045] - Providing casing elements with a receiving area or in particular with an opening, wherein the receiving area or in particular the opening is designed to be complementary in shape to the circumference of the pipe;

[0046] - Arranging the jacket elements in a row, preferably in the direction of the longitudinal extent and in particular through the opening, on the tube, wherein the jacket elements enclose the tube at least in sections with respect to a longitudinal extent of the tube and completely with respect to a circumference of the tube, thereby forming an adsorbent of the adsorber; wherein the method is characterized in that the jacket elements are produced from an adsorbent material in the adsorbent with a predominant proportion, in terms of mass fraction, of metal-organic framework compounds.

[0047] The advantage here is that the shell elements have a large internal surface area of ​​up to 4500 m due to the predominant proportion of metal-organic framework compounds in the adsorption material. 2 / g. This means that a particularly high proportion of refrigerant per volume of adsorbent is adsorbable and equally desorbable, which has a particularly advantageous effect on the convertible evaporation or adsorption enthalpy per volume of adsorbent. As a result, the adsorber of an adsorption chiller can be constructed particularly compactly, as its adsorption kinetics are improved. Furthermore, metal-organic framework compounds are particularly resistant to degradation of their adsorption capacity, especially when water or a water-alcohol mixture is used as the refrigerant, which is particularly advantageous with regard to the system efficiency of the adsorption chiller over its operating life and its service life.Likewise, shell elements with a predominant proportion of metal-organic framework compounds have proven to be particularly resistant and long-term stable against the thermal stresses encountered in adsorption chillers using water or a water-alcohol mixture as refrigerant.

[0048] According to a further development, it is possible to insert a spacer in the longitudinal direction between two adjacent shell elements. This is advantageous because the adsorber surface is thus increased in addition to the inner surface of the shell element. This is due to the fact that refrigerant molecules diffuse comparatively more easily through the porous and gas-permeable spacer than through the adsorption material itself.

[0049] Also advantageous is a form of embodiment according to which it can be provided that the casing elements are produced as pressed pieces from a supporting structure and adsorption material pressed with the supporting structure, so that a density of the adsorption material with a value higher than 0.2 g / cm 3 , in particular with a value from a range of values ​​comprising 0.5 g / cm 3 up to 2.2 g / cm 3 is achieved.

[0050] In this context, it can be provided that the shell elements are designed, in particular, to be disc-shaped or hollow-cylindrical, which significantly simplifies their manufacture and the assembly of the adsorber. By pressing the shell elements together or by compressing and squeezing them, the density of the shell elements or the density of the adsorption material, in particular of the metal-organic framework compounds, is increased, which improves the adsorption and desorption properties of the adsorbent. This allows the adsorber to operate for longer in the respective process step and increases the usable evaporation or condensation enthalpy, thus further improving the efficiency of the adsorption chiller. At the same time, the spacer can be designed such that its density is only insignificantly increased during pressing and, preferably, such that its porosity and gas permeability remain undamaged.This further increases the adsorption area of ​​the adsorbent and significantly improves the adsorption kinetics.

[0051] According to the invention, a manufacturing method of a jacket element for encasing a tube for an adsorber, in particular for an adsorber for an adsorption chiller, can also be provided, wherein the jacket element comprises an adsorption material with a predominant proportion, in particular in terms of mass fraction, of metal-organic framework compounds, which manufacturing method is characterized in that it comprises the following process steps:

[0052] - Providing a lattice-like or net-like supporting structure or a lattice-like or net-like supporting structure made of a thermally conductive material, in particular a metallic material;

[0053] - Pressing the adsorption material onto the supporting structure, whereby a compact is produced and whereby the supporting structure is embedded into the adsorption material by the pressing.

[0054] It can be provided that the supporting structure is first placed in a mold intended for the pressing production of the compact, so that the adsorption material is subsequently introduced into the mold, and then the adsorption material is pressed onto the supporting structure. The mold for producing the compact can already be a negative mold of the casing element thus produced. Thus, the manufacturing method can further comprise providing a mold, wherein this mold is essentially designed to complement the shape of the casing element thus produced.

[0055] Alternatively, a manufacturing method of a jacket element for encasing a tube for an adsorber, in particular for an adsorber for an adsorption chiller, is conceivable, wherein the jacket element comprises an adsorption material with a predominant proportion, in particular in terms of mass fraction, of metal-organic framework compounds, which manufacturing method is characterized in that it comprises the following process steps:

[0056] - Providing a plate-shaped lattice-like or net-like supporting structure or a lattice-like or net-like supporting structure made of a thermally conductive material, in particular a metallic material;

[0057] - agglomerating, vapor deposition, molding or depositing the adsorption material in the area of ​​the supporting structure, whereby an adsorption plate is produced and the supporting structure is embedded in the adsorption material;

[0058] - Punching or cutting out a contour of the casing element and an opening for the pipe in the casing element.

[0059] Alternatively, a manufacturing method of a jacket element for encasing a tube for an adsorber, in particular for an adsorber for an adsorption chiller, is conceivable, wherein the jacket element comprises an adsorption material with a predominant proportion, in particular in terms of mass fraction, of metal-organic framework compounds, which manufacturing method is characterized in that it comprises the following process steps:

[0060] - Providing a plate-shaped lattice-like or net-like supporting structure or a lattice-like or net-like supporting structure made of a thermally conductive material, in particular a metallic material;

[0061] - forming or overmolding the supporting structure with adsorption material, whereby an adsorption plate is produced and the supporting structure is embedded in the adsorption material;

[0062] - Punching or cutting out a contour of the casing element and an opening for the pipe in the casing element.

[0063] Alternatively, a manufacturing method of a jacket element for encasing a tube for an adsorber, in particular for an adsorber for an adsorption chiller, is conceivable, wherein the jacket element comprises an adsorption material with a predominant proportion, in particular in terms of mass fraction, of metal-organic framework compounds, which manufacturing method is characterized in that it comprises the following process steps:

[0064] - Providing a plate of adsorption material;

[0065] - pressing a respective grid-like or net-like flat supporting structure into the plate on both sides, whereby an adsorption plate is produced and wherein the supporting structure is embedded in the adsorption material;

[0066] - Punching or cutting out a contour of the casing element and an opening for the pipe in the casing element.

[0067] Furthermore, it can be provided that the adsorption plate is coated with metal foam.

[0068] This is particularly advantageous because, on the one hand, a metal foam coating allows for the thinnest possible spacer to be formed on a respective casing element. Another advantage is that metal foam exhibits high thermal conductivity while simultaneously exhibiting high porosity and gas permeability. These properties further enhance the previously described advantages of a spacer.

[0069] It can also be provided that the different manufacturing methods, or at least individual aspects or process steps thereof, can be combined with one another in order to produce a casing element. For a better understanding of the invention, it is explained in more detail with reference to the following figures.

[0070] They show in a highly simplified, schematic representation:

[0071] Fig. 1 shows a possible design of an adsorption chiller;

[0072] Fig. 2 shows a possible design of a section of an adsorber;

[0073] Fig. 3 shows a possible design of a casing element;

[0074] Fig. 4 shows a possible further embodiment of a casing element.

[0075] By way of introduction, it should be noted that in the variously described embodiments, identical parts are provided with identical reference symbols or component designations. The disclosures contained throughout the description can be applied analogously to identical parts with identical reference symbols or component designations. Furthermore, the position information chosen in the description, such as top, bottom, side, etc., refer to the directly described and illustrated figure, and these position information must be applied analogously to the new position in the event of a change in position.

[0076] Fig. 1 shows a possible embodiment of an adsorption chiller 1 in a highly simplified, schematic representation. The adsorption chiller 1 can comprise several process chambers 2, wherein a process chamber 2 can be charged or filled with refrigerant. The refrigerant can be water, for example, wherein the refrigerant can be introduced into the respective process chamber 2 by means of a multi-way valve 3 according to the process control of the adsorption chiller 1, or the loading of the individual process chambers 2 can be controlled by means of the multi-way valve 3. An adsorption chiller 1 can comprise at least one adsorber or desorber, which is simply referred to below as adsorber 4. The embodiment of an adsorption chiller 1 shown as an example in Fig. 1 can comprise two adsorbers 4, wherein one adsorber 4 can be accommodated in each process chamber 2. For better understanding, Fig.1 shows a view into a process chamber 2. Fig. 2 shows a highly simplified, schematic representation of a possible embodiment of a subsection of an adsorber 4. The same component designations and reference symbols are used in both Fig. 1 and Fig. 2, as well as in Fig. 3. For improved understanding, the following description of these representations should be understood in the context of an overall view of Fig. 1 and Fig. 2, as well as Fig. 3.

[0077] An adsorber 4 according to its possible embodiment shown in Figs. 1 and 2 can, within the meaning of the present invention, comprise a tube 5 through which a heat transfer medium flows and an adsorbent 8 that surrounds the tube 5 at least in sections with respect to a longitudinal extent 6 of the tube 5 and completely with respect to a circumference 7 of the tube 5. In accordance with these definitions, however, a process chamber 2 itself, in which an adsorber 4 is accommodated according to the present description, can alternatively be referred to synonymously as an adsorber 4 or as an adsorber or desorber.

[0078] In any case, the adsorption agent 8 is suitable for adsorbing or desorbing the refrigerant in the process chamber 2 according to its physical state. As can be seen from Fig. 2, the adsorption agent 8 can comprise jacket elements 9 arranged in a row along the longitudinal extent 6 of the tube 5, each jacket element 9 comprising an adsorption material 13 with a predominant proportion of metal-organic framework compounds. If refrigerant is now adsorbed in the adsorption agent 8, its condensation enthalpy is released, so that this can be absorbed and dissipated as heat by the heat transfer medium in the tube 5. If refrigerant is now desorbed in the adsorption agent 8, its vaporization enthalpy is released, which amount of energy is extracted in the form of heat from the heat transfer medium conveyed through the tube 5.

[0079] The illustrated shape and design of the section of the adsorber 4 is exemplary and should be understood as a schematic representation. It can be provided that an adsorber 4 is provided in a process chamber 2 of an adsorption chiller 1, which adsorber 4 has several running meters of a tube 5 according to the output of the adsorption chiller 1, which tube 5 preferably has an adsorbent 8 over a predominant portion. This is shown by way of example in the view into the process chamber 2 in Fig. 1. It can also be provided that a hollow cylindrical casing is provided around the adsorbent 8, which is porous or in particular designed as a finely perforated plate or sieve plate so that the coolant can flow through it without any significant diffusion resistance.

[0080] The adsorbent 8 can be formed from jacket elements 9 arranged in a row along the longitudinal extent 6 of the tube 5. In Fig. 3, such a jacket element 9 is shown in a highly simplified and schematic manner. It can be provided that a respective jacket element 9 of the adsorbent 8 comprises or has a supporting structure 10, by means of which supporting structure 10 the jacket element 9 can be stabilized with regard to its shape, for example because the adsorbent material 13 is penetrated by the supporting structure 10 or the supporting structure 10 is formed by the adsorbent material 13. As shown by way of example, the supporting structure 10 can be designed in a lattice or net-like manner and can be made of a metallic and / or a thermally conductive material. In this way, on the one hand, the jacket element 9 is dimensionally stabilized and, on the other hand, the transferability of the condensation and evaporation enthalpy inside the adsorbent 8 and in the direction of the tube 5 is improved.Alternatively, it can also be provided that the supporting structure 10 is completely embedded in the adsorption material 13.

[0081] The casing element 9 can also have a receiving area 11, wherein this receiving area 11 is designed to be substantially complementary in shape to the circumference 7 of the tube 5. Additionally, the casing element 9 can also be disk-shaped. Thus, a casing element 9 can be very easily pushed onto the tube 5 of an adsorber 4, so that the adsorbent 8 can be assembled from the casing elements 9. Thus, a casing element 9 completely encloses the tube 5, like a sleeve.

[0082] As can also be seen from Fig. 2, the adsorbent 8 can further comprise spacers 12, wherein a spacer 12 is provided between each two jacket elements 9 located closest in the longitudinal extension 6 of the tube 5. Provision can be made for the spacer 12 to be formed from a porous and gas-permeable material, such as a metal foam. It can also be provided that the spacer 12, such as in the form of a metal foam, is applied or applied directly as a coating to a jacket element 9 or to a side surface of a jacket element 9, as is illustrated schematically and by way of example in Fig. 3.

[0083] Furthermore, it can also be provided that the adsorbent 8 is produced by pressing together, at least in sections with respect to the longitudinal extent 6 of the tube 5, jacket elements 9 and spacers 12 arranged in a row along the longitudinal extent 6 of the tube 5, so that a density of the compressed adsorption material 13 is increased compared to a density of the non-compressed adsorption material 13. As a result, the density of the adsorption material 13 with a predominant proportion of metal-organic framework compounds can be approximated, for example, to the density of silica gel, whereby the inner surface of the adsorbent 8 per unit volume can thereby be increased compared to a non-compressed adsorption material 13.

[0084] Fig. 4 finally shows a possible further embodiment of a casing element 9. In this case, it can be provided that the casing element 9 comprises a hollow cylindrical tube section 16, wherein the receiving region 11 is thus formed by an inner surface of the tube section 16. The hollow cylindrical tube section 16 has a wall 14 with a wall thickness 15, wherein it can preferably be provided that the supporting structure 10 or, in particular, a grid designed as a supporting structure 10 is connected or coupled to the wall 14 and, over a predominant part of the wall thickness 15 of the wall 14, to the hollow cylindrical tube section 16.

[0085] In particular, it can be provided that the grid is formed from an aluminum alloy and is pressed into the wall 14, preferably on both sides or on both side surfaces or end faces of the hollow-cylindrical tube section 16, so that a positive or, under certain circumstances, a molded connection is established between the wall 14 and the grid. This creates a thermally conductive connection between the wall 14 and the grid. In this context, "both sides" can also be understood to mean that a grid is positively embossed or pressed into the wall 14 on each side. - l -

[0086] In this context, it can also be provided that heat-conducting elements are formed on the hollow-cylindrical tube section 16, projecting or extending radially in the direction of the adsorption material 13. For example, these heat-conducting elements can be formed by ribs, webs, or plates or small pieces that are formed on the hollow-cylindrical tube section 16 or on its wall 14. These heat-conducting elements can preferably have a smaller wall thickness 15 than the wall 14 or, in particular, the same wall thickness 15 as the wall 14, so that these heat-conducting elements are surrounded by adsorption material 13. It is also conceivable for the heat-conducting elements to be formed by a further grid network.In any case, the heat-conducting elements can be formed relative to the wall thickness 15 between a first grid in the region of a first end face of the hollow-cylindrical pipe section 16 and a second grid in the region of a second end face of the hollow-cylindrical pipe section 16. An end face of the hollow-cylindrical pipe section 16 is in any case formed at least parallel to the side surface of a casing element 9 and can preferably also be formed flush therewith or in a common plane.

[0087] In this context, it may further be provided that a grid has a variable mesh size in the radial direction and in the direction of a central axis of the hollow cylindrical pipe section 16. Likewise, it may be conceivably advantageous if, for example, two grids with different mesh sizes are provided instead of the variable mesh size, so that a grid with a narrower mesh size is formed in a radially inner region of the supporting structure 10 than in the radially outer region of the supporting structure 10. In this regard, as a simple alternative, a double fabric layer can also be provided in the radially inner region of the supporting structure 10.

[0088] Alternatively, or at least in combination with the above, it can further be provided that several grids with the same inner diameter and different outer diameters are formed in an overlapping manner on a side surface or end face of the casing element. This allows a proportion of grids or their material to increase in the radial direction toward the central axis of the hollow cylindrical tube section in order to further improve or increase the heat transfer or thermal conductivity toward the receiving area 11.The embodiments show possible embodiments, whereby it should be noted at this point that the invention is not limited to the specifically illustrated embodiments thereof, but rather various combinations of the individual embodiments with each other are also possible and this possibility of variation lies within the skill of the person skilled in the art in this technical field due to the teaching of technical action by means of the objective invention.

[0089] The scope of protection is determined by the claims. However, the description and drawings must be used to interpret the claims. Individual features or combinations of features from the various embodiments shown and described may represent independent inventive solutions. The problem underlying these independent inventive solutions can be derived from the description.

[0090] All information on value ranges in this description is to be understood as including any and all sub-ranges thereof, e.g. the information 1 to 10 is to be understood as including all sub-ranges starting from the lower limit of 1 and the upper limit of 10, ie all sub-ranges begin with a lower limit of 1 or greater and end with an upper limit of 10 or less, e.g. 1 to 1.7, or 3.2 to 8.1, or 5.5 to 10.

[0091] For the sake of clarity, it should be noted that some elements have been shown not to scale and / or enlarged and / or reduced in size to improve understanding of the structure.

[0092] Adsorption chiller

[0093] Trial Chamber

[0094] Multi-way valve

[0095] Adsorber

[0096] Pipe

[0097] Longitudinal extension

[0098] Scope

[0099] Adsorbent

[0100] Sheath element

[0101] supporting structure

[0102] Recording area

[0103] spacers

[0104] Adsorption material

[0105] wall

[0106] Wall thickness

[0107] Pipe section

Claims

Patent claims 1. Adsorption refrigeration machine (1) comprising a process chamber (2) which can be charged with refrigerant and an adsorber (4) accommodated in the process chamber (2), wherein the adsorber (4) comprises a tube (5) for the flow of a heat transfer medium and an adsorbent (8) which surrounds the tube (5) at least in sections with respect to a longitudinal extent (6) of the tube (5) and completely with respect to a circumference (7) of the tube (5), wherein refrigerant can be adsorbed or desorbed by the adsorbent (8) depending on its physical state in the process chamber (2), characterized in that the adsorbent (8) comprises jacket elements (9), wherein each jacket element (9) has an adsorption material (13) with a predominant proportion of metal-organic framework compounds.

2. Adsorption refrigeration machine (1) according to claim 1, characterized in that each casing element (9) comprises a stabilizing supporting structure (10), wherein the adsorption material (13) is penetrated by the supporting structure (10) or the supporting structure (10) is formed by the adsorption material (13).

3. Adsorption refrigeration machine (1) according to claim 2, characterized in that the supporting structure (10) is formed from a heat-conducting material, wherein the heat-conducting material is in particular a metallic material, in particular an aluminum, copper, steel or iron alloy.

4. Adsorption refrigeration machine (1) according to one of claims 2 or 3, characterized in that the supporting structure (10) has a receiving area (11), wherein the receiving area (11) of the supporting structure (10) is designed to be complementary in shape to the circumference (7) of the tube (5).

5. Adsorption refrigeration machine (1) according to one of the preceding claims, characterized in that each jacket element (9) is designed as a sleeve-shaped jacket element (9) which is fully circumferential with respect to the tube (5), wherein each The jacket element (9) has an opening so that the jacket elements (9) encompass the pipe (5).

6. Adsorption refrigeration machine (1) according to one of claims 2 to 4, characterized in that the supporting structure (10) comprises a grid or grid network passing through the adsorption material (13), wherein by means of the grid network a vapor-permeable and / or gas-permeable supporting structure is formed which has a shape-stabilizing effect on the adsorption material (13).

7. Adsorption refrigeration machine (1) according to claim 4 and 6, characterized in that the receiving area (11) is formed from a hollow cylindrical tube section (16) with a wall (14) with a wall thickness (15), wherein the grid is connected to the wall (14), in particular is connected in a thermally conductive manner, wherein an overlap of the wall (14) with the grid is provided over a predominant part of the wall thickness (15).

8. Adsorption refrigeration machine (1) according to claim 7, characterized in that the grid is pressed into the wall (14), wherein the receiving area (11) is preferably formed from an aluminum alloy and wherein the grid is specifically formed from a metallic alloy, in particular from an aluminum alloy.

9. Adsorption refrigeration machine (1) according to one of the preceding claims, characterized in that a spacer (12) is provided between two jacket elements (9) lying closest in the longitudinal extension (6) of the tube (5), wherein the spacer (12) is formed from a porous and / or gas-permeable material.

10. Adsorption refrigeration machine (1) according to claim 6, characterized in that the spacer (12) has the same cross-section as a casing element (9) and a thickness from a thickness range comprising 0.05 mm to 2 mm.

11. Adsorption refrigeration machine (1) according to one of claims 6 or 7, characterized in that the spacer (12) is applied as a coating to each of the casing elements (9) of the adsorbent (8), wherein the spacer (12) is formed in particular from metal foam.

12. Adsorption refrigeration machine (1) according to one of claims 6 to 8, characterized in that the adsorbent (8) is produced by, with respect to the longitudinal extent (6) of the tube (5), at least in sections pressing together casing elements (9) and spacers (12) arranged in a row in the longitudinal extent (6) of the tube (5), so that a density of the adsorption material (13) in the adsorbent (8) or in the casing elements (9) has a higher value than 0.2 g / cm 3 , in particular a value from a range of values ​​comprising 0.5 g / cm 3 up to 2.2 g / cm 3 , has.

13. Adsorption refrigeration machine (1) according to one of claims 1 to 5, characterized in that the jacket elements (9) for producing the adsorbent (8) are arranged in a row directly adjacent to one another with respect to the longitudinal extent (6) of the tube (5) and are pressed against one another at least in groups with respect to the longitudinal extent (6) of the tube (5), so that a density of the adsorption material (13) in the adsorbent (8) or in the jacket elements (9) has a value higher than 0.2 g / cm 3 , in particular a value from a range of values ​​comprising 0.5 g / cm 3 up to 2.2 g / cm 3 , has.

14. Adsorption refrigeration machine (1) according to one of claims 2 to 10, characterized in that the casing elements (9) are produced as pressed pieces from the supporting structure (10) and adsorption material (13) pressed with the supporting structure (10), so that a pressed piece has a density of its adsorption material (13) higher than 0.2 g / cm 3, in particular a value from a range of values ​​comprising 0.5 g / cm 3 up to 2.2 g / cm 3 , has.

15. A method for producing an adsorber (4) for an adsorption refrigerator (1), comprising the following method steps: - Providing a tube (5) with a longitudinal extension (6) and a circumference (7), wherein the tube (5) can be flowed through with heat transfer medium; - Providing casing elements (9) with a receiving area (11), wherein the receiving area (11) is at least partially designed to be complementary in shape to the circumference (7) of the tube (5); - Arranging the jacket elements (9) in a row on the tube (5), wherein the jacket elements (9) enclose the tube (5) at least in sections with respect to a longitudinal extent (6) of the tube (5) and completely with respect to a circumference (7) of the tube (5), whereby an adsorbent (8) of the adsorber (4) is formed; characterized in that the jacket elements (9) are produced from an adsorption material (13) with a predominant proportion of metal-organic framework compounds.

16. Method according to claim 12, characterized in that the casing elements (9) are produced as pressed pieces from a supporting structure (10) and adsorption material (13) pressed with the supporting structure (10), so that a density of the adsorption material (13) with a higher value than 0.2 g / cm 3 , in particular with a value from a range of values ​​comprising 0.5 g / cm 3 up to 2.2 g / cm 3 is achieved.

17. A method for producing a casing element (9) for encasing a tube (5) for an adsorber (4), wherein the casing element (9) comprises an adsorption material (13) with a predominant proportion of metal-organic framework compounds, characterized in that the method comprises the following process steps: - Providing a grid-like or net-like supporting structure (10) made of a thermally conductive material, in particular a metallic material; - Pressing the adsorption material (13) with the supporting structure (10), whereby a compact is produced and whereby the supporting structure (10) is embedded in the adsorption material (13) by the pressing, so that the casing element (9) is produced.

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