Balloons for use in energy handling systems

Abstract

A balloon for use in an energy handling system based on a vessel and a balloon mounted therein, the balloon comprising a balloon wall, wherein the balloon wall includes at least one variation in structural properties inducing a variation in elasticity configured to control the expansion behaviour of the balloon at that location. The variation in structural properties may be a variation in balloon wall thickness or a variation in material used, e.g. in elasticity. Examples are balloons having at least one 10 local thickening located where the balloon needs to touch the vessel the latest when expanded or balloons having at least one local thickening near an inlet or a sharp edge in the vessel wall, such as an assembly gap between components, avoiding rupture.

Description

[0001] BALLOONS FOR USE IN ENERGY HANDLING SYSTEMS

[0002] Technical field of the invention

[0003] The present invention relates to the field of energy handling systems, and more specifically to balloons used within vessels in such systems.

[0004] Background of the invention

[0005] Energy handling systems, such as heat exchange units, are essential for the conversion, storage, and transmission of energy across various applications. A wide number of energy handling systems is available on the market, nevertheless, only few of them are really efficient. An example of a really efficient energy handling system is described in European patent application EP4224103, describing a system using a balloon mounted in a vessel to facilitate energy handling processes. The balloon functions by expanding and contracting, thereby enabling the system to handle energy efficiently through mechanisms like heat exchange, pressure regulation, and volume adjustment.

[0006] An important aspect of these systems is the expansion behavior of the balloon within the vessel. The manner in which the balloon expands can significantly impact the efficiency and effectiveness of energy handling. Challenges arise when the expansion is uncontrolled or uneven, leading to premature contact between the balloon and certain areas of the vessel wall, hence resulting in reduced efficiency. Such contact can result in suboptimal performance, increased wear, or even damage to the balloon.

[0007] Structural features of the vessel, including sharp edges, gaps, or filling holes, present additional concerns. When a balloon expands within a vessel that has these features, there is a risk of stress concentration on the balloon material at these points. This can lead to potential rupture or leakage, compromising the integrity of the system. Preventing undue stress and ensuring the balloon can withstand the operational environment without failure is a significant challenge.

[0008] Manufacturing variations also contribute to the complexities faced in this field. Inconsistencies in balloon wall thickness or material properties due to manufacturing tolerances can affect the balloon's expansion behavior. Such variations may lead to unpredictable performance, making it difficult to ensure that the system operates within the desired parameters consistently.

[0009] Given these challenges, there is a continuing need for advancements in energy handling systems. Enhancements that allow for better control of balloon expansion, mitigate risks associated with vessel structural features, and reduce the impact ofmanufacturing variations would significantly improve the performance and reliability of these systems.

[0010] There is thus still a need in the art for devices and methods that address at least some of the above problems.

[0011] Summary of the invention

[0012] It is an object of embodiments of the present invention to optimize the energy handling performance of systems utilizing a balloon mounted within a vessel. This objective is accomplished by the aspects of the present invention.

[0013] In a first aspect, the present invention relates to a balloon for use in an energy handling system based on a vessel and a balloon mounted therein, the balloon comprising a balloon wall, wherein the balloon wall includes at least one variation in structural properties inducing a variation in elasticity configured to control the expansion behavior of the balloon at that location. This allows the expansion behavior of the balloon to be controlled by controlling the elasticity, so that the expansion behavior in the vessel fits the expansion behavior of the balloon required for good, e.g. optimal, energy handling properties.

[0014] In some embodiments, the at least one variation in structural properties may for example be a difference, e.g. locally, in the thickness of the balloon wall. In some embodiments the different elasticity, e.g. a decreased elasticity, can thus be obtained by providing a wall at a certain location or in a certain region that is thicker than outside this region. The balloon wall then includes a local thickening.

[0015] In some embodiments, the at least one variation in structural properties may for example be a difference in material properties, as for example expressed as a difference in shore hardness such as a shore A hardness, a difference in Young’s modulus, a difference in bulk modulus, a difference in elastic modulus, etc. In some embodiments, the balloon wall may at certain positions or in certain regions be made of a different material, i.e. a material having a higher shore A value (compared to the material used outside that region) thus resulting in a reduced elasticity at that position or in that region.

[0016] In some embodiments, the local elasticity variation may be an increase in elasticity rather than a reduction, allowing to promote expansion of the balloon in a predetermined manner, e.g. according to a predetermined shape. In this way, the moment of expansion of different points of the balloon wall as well as the shape to which the balloon expands can be controlled. One may for example hence promote that the balloon expands faster in one region than in another. The latter can e.g. also be used to prevent contactbetween the balloon and a vessel wall during operation as long as possible. Such a variation in elasticity may be caused by a thickness reduction rather than a thickness increase or by locally using materials with different properties.

[0017] In some embodiments, the balloon has an elongated shape and is being configured for being mounting in the vessel at the two extremities of the balloon, whereby in a region where the balloon needs to touch the vessel the latest, the balloon has a variation in structural properties resulting in a reduced elasticity. This makes the expansion behavior less subject to manufacturing variations, resulting in an improved expansion behavior of the balloon in the vessel. Unwanted contact between the center of the balloon wall and the vessel wall can be reduced or even avoided. The efficiency of the energy handling system can hence be optimum. The volume between the outside of the balloon and the vessel wall can be reduced to a large extent while the surface of the vessel wall that is not in contact with the balloon can remain substantially the same. According to some embodiments, the surface of the vessel wall that is not in contact with the balloon can remain maximal.

[0018] In some embodiments, the balloon has, in a region of the balloon corresponding with a sharp edge in the vessel wall of the energy handling system when the balloon is mounted in the vessel and expanded, a variation in structural properties inducing a reduced elasticity. This reduces or even avoids the risk of rupture of the balloon near gaps in the vessel wall, since the balloon is less inclined to locally fit to the gap or edge in the vessel wall.

[0019] In embodiments, the sharp edge may be an assembly gap between different components mounted together to form the inner volume of the vessel.

[0020] In embodiments, a region with a variation of structural properties inducing a reduced elasticity may be positioned, when the balloon is mounted in the vessel and expanded, near a filling hole in the vessel of the energy handling system, allowing to seal, when the balloon is fully expanded, the filling hole whereby the balloon wall is substantially flush with the vessel wall surrounding the filling hole. This prevents the balloon wall from being deformed by expanding in the filling hole, which would increase the risk of rupture of the balloon.

[0021] In embodiments, the at least one region with varied structural properties inducing a reduced elasticity of the balloon wall may actually be a plurality of regions with varied structural properties inducing a reduced elasticity, distributed along the surface of the balloon.

[0022] In some embodiments, the region with varied structural properties inducing a reduced elasticity may be implemented as a gradual change in structural properties,e.g. an increase in wall thickness, from an extremity of the balloon towards the center of the balloon.

[0023] In embodiments where the region with altered structural properties to induce a reduced elasticity is obtained by a local thickening of the balloon wall, the thickness of the balloon at the position of a local thickening may be between 1.1 and 10 times as thick compared to the thickness of the balloon where no local thickening is present. In some embodiments, the thickness of the balloon at the position of a local thickening may be between 1.3 and 8 times as thick compared to the thickness of the balloon where no local thickening is present. In some embodiments, the thickness of the balloon at the position of a local thickening may be between 1.5 and 5 times as thick compared to the thickness of the balloon where no local thickening is present.

[0024] In a second aspect, the present invention relates to an energy handling system comprising a vessel and a balloon according to any embodiments of the first aspect.

[0025] In embodiments, the balloon may have an elongated shape, the balloon being mounted to the vessel at two extremities of the elongated shape in a pretensed manner.

[0026] In embodiments, the balloon may be configured such that the center of the balloon contacts the wall of the vessel after peripheral portions of the balloon when the balloon is being filled.

[0027] In embodiments, the vessel may comprise a filling hole in the vessel wall, and at least one location with varied structural properties inducing a reduced elasticity in the balloon may be configured to hermetically seal the filling hole when the balloon is completely filled.

[0028] In some embodiments, the energy handling system comprises at least two vessels with balloons as indicated above, the two vessels being fluidically interconnected with each other, wherein the balloons comprise at least one local variation in structural properties configured for hermetically sealing the fluid interconnection between the at least two fluidically interconnected vessels when one of the balloon is completely filled. In this way an energy handling system thus may be provided based on at least two vessel / balloon based units that are fluidically interconnected and that are, when one of the balloons is completely filled, hermetically sealed from each other, while not requiring a separate valve for obtaining such hermetic sealing.

[0029] In embodiments, the energy handling system may be a heat exchange unit. It is an advantage of embodiments of the present invention that the expansion behavior of the balloon can be additionally controlled by adjusting the structural properties of the balloon wall, such as for example the wall thickness or the shorehardness of the material used, so that the expansion behavior in the vessel fits the requirements for optimal heat exchanging properties. It is an advantage of embodiments of the present invention that the expansion behavior is less subject to manufacturing variations, resulting in an improved expansion behavior of the balloon within the vessel. It is an advantage that unwanted contact between the center of the balloon wall and the vessel wall can be avoided. It is an advantage of embodiments of the present invention that the efficiency of the energy handling system can be optimized. It is an advantage of energy handling systems making use of the balloon-in-vessel concept that the volume between the outside of the balloon and the vessel wall can be reduced to a large extent while the surface area of the vessel wall not in contact with the balloon can remain substantially the same. According to some embodiments, the surface area of the vessel wall that is not in contact with the balloon can remain maximal. It is an advantage of embodiments of the present invention that by adjusting the balloon wall properties locally, the risk of rupture near gaps or sharp edges in the vessel wall can be reduced or even avoided. It is an advantage of embodiments of the present invention that the balloon wall is not deformed by expanding into filling holes, since this increases the risk of rupture. It is an advantage of embodiments of the present invention that local variations in structural properties can be distributed along the surface of the balloon, allowing precise control over the expansion behavior in multiple regions. It is an advantage of embodiments of the present invention that the variation of structural properties can gradually increase from an extremity of the balloon towards the center, enabling controlled expansion that matches the vessel geometry. It is an advantage of embodiments of the present invention that the variation of structural properties of the balloon wall in a region can be a local thickening of the balloon wall between 1.1 and 10 times as thick compared to where no local thickening is present, providing flexibility in design to optimize performance. In some embodiments, the thickness in the region of a local thickening may be between 1.3 and 8 times, or between 1.5 and 5 times as thick compared to where no local thickening is present, allowing for an optimal balance between flexibility and strength.

[0030] In another aspect, the present invention also relates to a balloon for use in an energy handling system for converting, transmitting or storing energy making use of a vessel and a balloon mounted therein, the balloon having a balloon wall, wherein the balloon wall comprises

[0031] an elastic layer for allowing the balloon to expand in the vessel, andat least one further layer positioned adjacent the elastic layer, the at least one further layer comprising a first barrier layer preventing interaction between a first fluid used in the energy handling system and the elastic layer of the balloon wall.

[0032] It is an advantage that the first barrier layer may be a diffusion-limiting or a diffusionpreventing layer to prevent that the first fluid crosses the balloon wall or alternatively may be a layer that prevents interaction of the first fluid with or deterioration of the elastic material of the elastic layer. The layer does not need to be fixed to the elastic layer, but may be.

[0033] According to some embodiments of the present invention, the at least one further layer may comprise a second barrier layer preventing interaction between a second fluid used in the energy handling system and the elastic layer of the balloon wall.

[0034] It is an advantage that also this second barrier layer may be a diffusion-limiting or a diffusion-preventing layer to prevent that the second fluid crosses the balloon wall or alternatively may be a layer that prevents interaction of the second fluid with or deterioration of the elastic material of the elastic layer. The layer does not need to be fixed to the elastic layer, but may be.

[0035] The first barrier layer respectively the second barrier layer may prevent diffusion from a fluid used in the energy handling system through the balloon wall.

[0036] The first barrier layer respectively the second barrier layer may prevent interaction between the first fluid respectively second fluid used in the energy handling system and the elastic material of the elastic layer.

[0037] The first barrier layer respectively the second barrier layer may be fixed substantially over its full surface to the elastic layer.

[0038] The balloon wall may be a stack of the first barrier layer, the elastic layer positioned aside the first barrier layer, and the second barrier layer being positioned opposite the elastic layer with reference to the position of the first barrier layer.

[0039] In some embodiments, the first barrier layer and the second barrier layer may be positioned at the same side of the elastic layer, although this is less optimal for protecting the elastic material from being influenced by at least one of the fluids in the energy handling system used.

[0040] In embodiments of the present invention, the balloon may have a balloon wall having properties combining the features of different aspects as described above.

[0041] Particular and preferred aspects of the invention are set out in the accompanying independent and dependent claims. Features from the dependent claims may be combined with features of the independent claims and with features of other dependent claims as appropriate and not merely as explicitly set out in the claims.Although there has been constant improvement, change and evolution of devices in this field, the present concepts are believed to represent substantial new and novel improvements, including departures from prior practices, resulting in the provision of more efficient, stable and reliable devices of this nature.

[0042] The above and other characteristics, features and advantages of the present invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, which illustrate, by way of example, the principles of the invention. This description is given for the sake of example only, without limiting the scope of the invention. The reference figures quoted below refer to the attached drawings.

[0043] Brief description of the drawings

[0044] FIG. 1 is a schematic representation of an energy handling system wherein a balloon according to an embodiment of the present invention can be used.

[0045] FIG. 2 illustrates a heat exchange unit as can be used in an energy handling system wherein balloons according to embodiments of the present invention can be used.

[0046] FIG. 3 illustrates possible thermodynamic conditions as can be obtained using an embodiment of the present invention.

[0047] FIG. 4 illustrates a possible expansion of a balloon in a vessel for a more conventional balloon (A) and for a balloon with a variation in structural properties (B & C) according to an embodiment of the present invention.

[0048] FIG. 5 illustrates the problem of expansion of the balloon in a small gap (A) and the improved behaviour for a balloon according to an embodiment of the present invention (B).

[0049] FIG. 6 illustrates the problem of expansion of the balloon in a venting hole (A) and the improved behaviour for a balloon according to an embodiment of the present invention (B).

[0050] FIG. 7 and FIG. 8 illustrate a system based on 4 heat exchanging units respectively on 8 heat exchanging units for obtaining an energy handling system that can operate in a continuous mode, using heat exchanging units wherein intermediate valves can be omitted, according to embodiments of the present invention.

[0051] FIG. 9 illustrates a heat exchange using a balloon having a multilayer wall according to an embodiment of an aspect of the present invention.

[0052] In the different figures, the same reference signs refer to the same or analogous elements.Description of illustrative embodiments

[0053] The present invention will be described with respect to particular embodiments and with reference to certain drawings but the invention is not limited thereto but only by the claims. The drawings described are only schematic and are non-limiting. In the drawings, the size of some of the elements may be exaggerated and not drawn on scale for illustrative purposes. The dimensions and the relative dimensions do not correspond to actual reductions to practice of the invention.

[0054] The following terms are provided solely to aid in the understanding of the invention.

[0055] As used herein, and unless otherwise specified, the term "local thickening" refers to a portion of the balloon wall where the wall thickness is increased relative to adjacent portions, such that the increased thickness is localized to selected regions of the balloon wall. Examples of specific embodiments of "local thickening" include areas where the balloon wall is reinforced with additional layers, sections molded with greater material accumulation, or regions where material properties are modified to increase thickness, resulting in an increased wall thickness at that location compared to surrounding areas.

[0056] As used herein, and unless otherwise specified, the phrase "configured to control the expansion behavior" refers to being designed or arranged in a manner that influences how the balloon expands when filled or pressurized, directing the expansion in a predetermined way at specific locations. Examples include incorporating local thickenings to reinforce certain areas of the balloon wall, thereby affecting the deformation pattern during inflation to ensure desired contact timings with the vessel wall or to prevent overstretching at critical points.

[0057] As used herein, and unless otherwise specified, the expression "expansion behavior" refers to the manner in which the balloon changes its shape, size, or volume when being filled or inflated within the vessel. Examples of "expansion behavior" include the rate at which different parts of the balloon expand, the sequence in which various regions of the balloon contact the vessel wall during inflation, or the overall deformation pattern that dictates how the balloon conforms to the vessel's interior.

[0058] As used herein, and unless otherwise specified, the phrase "elongated shape" refers to a shape characterized by a length dimension significantly greater than its width or diameter, resulting in a form that extends longitudinally along an axis. Examples of specific embodiments of "elongated shape" include balloons designed to be mounted within a vessel by their two ends, allowing them to span the length of the vessel.As used herein, and unless otherwise specified, the phrase "mounted in the vessel at the two extremities of the balloon" refers to the balloon being secured or attached at its two end regions to corresponding locations at or near the ends of the vessel, such that the balloon is supported and held in place at both ends within the vessel. Examples include attaching the ends of the balloon to inlet and outlet ports, flanges, or fittings provided at the vessel's extremities, ensuring proper alignment and tension.

[0059] As used herein, and unless otherwise specified, the expression "needs to touch the vessel the latest" refers to a portion of the balloon that is intended to make contact with the vessel wall after other portions have already done so during the balloon's expansion; it is the last part of the balloon to contact the vessel wall upon inflation. Examples include designing the central region of an elongated balloon with a local thickening so that, as the balloon inflates, the ends or peripheral regions expand first to contact the vessel wall, while the thickened central region expands more slowly and contacts the vessel wall subsequently.

[0060] As used herein, and unless otherwise specified, the term "sharp edge in the vessel wall" refers to any abrupt change or discontinuity on the surface of the vessel's interior wall that forms an edge, corner, or protrusion capable of causing localized stress or potential damage to the balloon upon contact. Examples include edges formed at joints between assembled vessel components, protrusions from internal structures or fittings, or imperfections resulting from manufacturing processes.

[0061] As used herein, and unless otherwise specified, the term "assembly gap" refers to a space or discontinuity between components that are assembled together to form the inner volume of the vessel, which may create a gap, recess, or uneven surface on the vessel wall. Examples of "assembly gap" include the interface between flanged sections of the vessel, gaps at sealing joints, or spaces resulting from the assembly of modular vessel parts.

[0062] As used herein, and unless otherwise specified, the expression "gradual increase in wall thickness" refers to a continuous and progressive increment in the thickness of the balloon wall over a distance, without abrupt changes, from one point to another within the balloon. Examples include a design where the wall thickness of the balloon increases smoothly from the ends towards the center, creating a tapered effect that reinforces specific regions and controls the expansion profile during inflation.

[0063] As used herein, and unless otherwise specified, the phrase "mounted in a pretensed manner" refers to installing the balloon under tension between its two extremities within the vessel, such that the balloon is stretched or pre-stressed alongits length prior to inflation. Examples include securing the ends of the balloon to the vessel in a way that eliminates slack, ensuring the balloon remains taut and properly positioned when not inflated, which can enhance expansion control and prevent undesired movement.

[0064] As used herein, and unless otherwise specified, the phrase "hermetically seal" refers to creating a seal that is completely airtight, effectively preventing the passage of gases or fluids through the sealed interface. Examples include the balloon expanding to press firmly against the regions around a filling hole in the vessel, using the local thickening to maintain flush with the average wall of the vessel wherein the inlet hole is positioned - and not locally following the filling hole recess - thereby sealing it entirely when the balloon is fully expanded.

[0065] As used herein, and unless otherwise specified, the term "energy handling system" refers to any system or apparatus that manages the transfer, storage, or conversion of energy in various forms, including thermal, mechanical, or fluid energy, within a controlled environment. Examples include systems such as heat exchangers, energy storage systems, energy conversion systems, etc. to facilitate the handling of energy between different mediums or processes.

[0066] As used herein, and unless otherwise specified, the term "filling hole" refers to an opening in the vessel wall that allows for the introduction or removal of fluids into or from the vessel or the balloon contained therein. Examples include ports equipped with valves or fittings, apertures designed for filling purposes, or access points used during the initial setup, maintenance, or operation of the energy handling system. Nevertheless, it is an advantage of at least some embodiments of the present invention, that valves may not be necessary in the energy handling systems since the balloon may function as valve, inducing hermetic sealing when it presses against the vessel wall.

[0067] The invention will now be described by a detailed description of several embodiments of the invention. It is clear that other embodiments of the invention can be configured according to the knowledge of persons skilled in the art without departing from the technical teaching of the invention, the invention being limited only by the terms of the appended claims.

[0068] In a first aspect, the present invention relates to a balloon for use in an energy handling system based on a vessel and a balloon mounted therein. In embodiments, the energy handling system may be configured to convert, store, and / or transmit energy by means of the balloon within the vessel. The balloon comprises a balloon wall, wherein the balloon wall includes at least one variation in structural properties inducing a variation in elasticity configured to control the expansion behavior of the balloon atthat location, thereby promoting optimal energy handling. Such a variation may for example be induced near an assembly gap, in a region where the balloon should expand later than in other regions, in a region around a sharp edge or in a region where the interaction between the vessel wall and the balloon induces stress on the balloon. Such a balloon may be especially suitable for use in an energy handling system as described in European patent application EP4224103 or as described in International patent application WO2023 / 148229, although embodiments are not limited thereto. A variation in structural properties inducing a variation in elasticity may in some embodiments be a variation in the wall thickness. Typically a larger wall thickness will result in a reduced elasticity, whereas a smaller wall thickness will result in an increased elasticity. A reduced elasticity may be used for avoiding that the balloon locally expands into gaps or to guarantee that the expansion of the balloon in regions with reduced elasticity occurs later than in other regions. Another possibility to induce a variation in structural properties is the local use of a different material having different elasticity properties compared to the remaining part of the balloon. Techniques are known to use different types of materials, e.g. different types of rubbers, in different parts of a balloon. In embodiments of the present invention, this can be used for controlling the expansion behaviour near gaps, near holes in the vessel or to tune the expansion behaviour. The balloon may be made of any suitable material such as rubber materials suited for the temperature ranges and the fluids that are applied. The material may be selected as function of the temperature that will be used in the system. As indicated the balloon may exist of different materials such as for example materials with different shore hardness values or may show different balloon wall thicknesses. Techniques for fabricating balloons with varying balloon wall thicknesses or with varying material properties in different regions of the balloon are known by the person skilled in the art. In embodiments, the local variation of the structural properties may comprise a gradual change in material properties in the wall, e.g. from an extremity of the balloon towards a center of the balloon.

[0069] Embodiments of the present invention need not be limited to balloons having a single reason with varied material properties.

[0070] In embodiments where the variation in elasticity is caused by varying the thickness of the balloon, such a variation in thickness may comprise a thickness being between 1.1 and 10 times as thick compared to the thickness of the balloon in remaining parts of the balloon. In some embodiments, the thickness of the balloon at the position of a local variation may be between 1.3 and 8 times as thick compared to the thickness of the remaining parts of the balloon wall. In some embodiments, the thickness of the balloonat the position of a local thickening may be between 1.5 and 5 times as thick compared to the thickness of the balloon wall at other positions.

[0071] For reasons of illustration, a schematic representation of an exemplary energy handling system 1 as described in WO2023 / 148229 is first illustrated. The energy handling system 1 is based on one or more units 100, which may be referred to as a HBVI-unit (Hydraulic Balloon Vessel Interface). The one or more units 100, e.g. heat exchange units, may be used for performing compression and / or expansion of a fluid, used in the energy handling action. Since in the units 100 typically heat will be exchanged, in the following examples and description reference also may be made to heat exchange units but it is to be noted that the invention is not limited to heat exchange and other types of energy also could be envisaged. The one or more units 100 may be controlled by a controller 2. Such a controller may comprise any suitable processor. In some embodiments, such a controller may be configured for controlling fluids in the one or more units, for inducing energy exchange. The controller 2 may be programmed for controlling the energy exchange process to occur under substantially isentropic, isobaric, isothermic and / or polytropic conditions, during at least 50% of the energy exchange process, advantageously during at least 60% of the energy exchange process or at least 75% of the energy exchange process or at least 90% of the energy exchange process. It is an advantage of at least some embodiments of the present invention that the conditions under which the energy exchange process can occur can be fully controlled, so that a substantially isothermic process, a substantially isentropic process, a substantially isobaric process, a polytropic process or a combination thereof can be selected and fully controlled. For controlling the fluids in the at least one energy exchange unit 100, the energy handling system 1 may comprise one or more pumping systems 3. It is to be noted that in systems according to embodiments of the present invention, particular temperature and pressure conditions can be maintained in the HBVI’s used in the system for inducing an efficient process. FIG. 2 illustrates an energy exchange unit allowing for exchanging heat between a first substance 110 and a second substance 120. The first substance may in some embodiments be a liquid, e.g. water. The first substance may in some embodiments be a supercritical gas. The energy exchange unit 100 comprises a first inner compartment 130 and a second outer compartment 140. The first inner compartment 130 and the second outer compartment 140 are positioned adjacent each other and are separated by an energy exchange surface 150. The energy exchange surface 150, corresponding with the outer surface of the first inner compartment 130, is defined by the outer surface of a vessel. Since high pressures may be induced in the first inner compartment 130, the outer surface ofthe first inner compartment 130, i.e. the heat exchange surface 150, typically may be made of a pressure resistant material. The vessel may be substantially cylindrically shaped and the first inner compartment and the second outer compartment may be configured as substantially concentric compartments. The compartments may be substantially cylindrically shaped. Alternatively, the compartment also may have any other suitable shape. According to the exemplary embodiment shown in FIG. 2, a balloon 160 is being mounted in the first inner compartment 130 so as to form in the first inner compartment 130 a hermetically sealed volume 170 between the outer surface of the balloon 160 and the energy exchange surface 150. Advantageously, the balloon 160 is fixed at two positions in the first inner compartment 130 to form the hermetically sealed volume 170 but to further not touch the walls (or touch them as little as possible) of the first inner compartment 130 during the heat exchange process. The balloon 160 may be fixed in a pre-tensioned manner. The balloon 160 typically may be filled with a balloon fluid 180. The balloon fluid 180 may be oil, although embodiments are not limited thereto. The balloon fluid 180 may be pumped towards the balloon or away from the balloon 160 in the energy handling system. The balloon is configured such with respect to the inner compartment that it forms the hermetically sealed volume 170 that is filled with the first substance 110. In some embodiments, The second outer compartment 140 is, in embodiments according to the present invention, being filled with the second substance 130. The second substance may be a liquid. The second substance 140 may be a cold liquid or may be a warm liquid. In some embodiments, the second substance may be a gas. The second outer compartment 140 may in some embodiments be isolated from the outer world by an isolation tube 190. The isolation tube may be an isolation tube providing an additional cavity around the second outer compartment, whereby the additional cavity may be under vacuum or for example filled with an isolation fluid.

[0072] According to embodiments of the present invention, the area of the heat exchange surface 150 that is in contact with the first substance 110 and a second substance 140 remains substantially the same during the energy exchange process. This is caused by the balloon expanding without touching the wall of the vessel. By providing substantially the same heat exchange surface area during the energy exchange process, the energy conversion system can be performed with high efficiency, i.e. with high yield. Where reference is made to the surface area of the heat exchange surface being substantially the same during the energy exchange process, this means that at least during 90% (for example during 95% or during 98%) of the time of energy exchange in the system, the surface area of the heat exchange surface that is in contactwith the first substance and the second substance varies less than 10% (for example varies less than 5%, for example less than 2%).

[0073] As indicated above, the energy handling system may be equipped with a controller and the heat exchange unit may be controlled to induce a heat exchange process at the heat exchange surface. The heat exchange process may be controlled to occur at a pressure in the range 200 to 700 bar, e.g. in the range 200 to 400 bar. Further as indicated above, the heat exchange process may be controlled to operate substantially isothermic process, a substantially isentropic process, a substantially isobaric process, a polytropic process or a combination thereof.

[0074] By way of illustration, embodiments not being limited thereto, an example of different thermodynamic processes is shown in FIG. 3. In the example shown on the left hand side of FIG. 3, a polytropic process is shown. In the central portion of FIG. 3, an isobaric process is shown, where the pressure can be kept substantially constant. Furthermore, on the righthand side of FIG. 3, an isothermal process is shown, where the temperature can be kept constant. As indicated above, it is an advantage of embodiments of the present invention that particular temperature and pressure conditions can be maintained in the HBVI’s used in the system for inducing an efficient process.

[0075] By way of illustration, embodiments of the present invention not being limited thereto, a number of exemplary embodiments will now further be described, illustrating standard and optional features of embodiments of the present invention.

[0076] FIG. 4 illustrates the effect of balloons according to embodiments of the present invention. In FIG. 4 (A), a balloon is illustrated that has the same structural properties over its full wall. The balloon is suspended at the outer ends in the vessel. The vessel also shows a filling hole 410. When the balloon is expanded, the balloon wall 160 may touch the heat exchange surface 150 of the vessel early in its center areas, resulting in less efficient operation of the heat exchange unit shown. In FIG. 4 (B) and FIG. 4 (C), a balloon according to an embodiment of the present invention is shown, again suspended in the vessel at its ends. In FIG. 4(B) the balloon is only partly expanded. The balloon wall 160 has a local variation in properties, i.e. different structural properties in a local region 420 of the balloon wall 160, in the present example being a local thickening in the center region, resulting in a reduced elasticity so that the balloon expands latest in this center region, resulting in an optimal expansion behaviour for heat exchange. In FIG. 4 (C) the balloon wall 160 is shown when it is fully expanded. It then contacts the heat exchange surface 150 of the vessel completely. Whereas in the present example the reduced elasticity is obtained by local region 420 of the balloonwall being thicker, a similar result can be obtained by locally using a different material having a lower elasticity.

[0077] FIG. 5 illustrates another example of a balloon according to an embodiment of the present invention. FIG. 5 (A) illustrates a vessel that is assembled of different parts 510a, 510b, 510c. As can be seen, between part 510a and 510b an assembly gap 520 occurs. When using a conventional balloon, the balloon wall 160 may extend into a small gap between different parts forming the vessel. This results in a higher risk for rupture of the balloon wall 160. FIG. 5 (B) illustrates a balloon wall according to an embodiment of the present invention whereby, when the balloon expands, near the position of the assembly gap 520, the balloon wall 160 shows a local region 420 with a variation in structural properties compared to the rest of the balloon wall 160, in the present example being a local thickening. The latter results in a reduced elasticity, resulting in the fact that the balloon does not enter the assembly gap 520 but crosses the gap and lies flush with the remaining surface of the vessel. Whereas in the present example the reduced elasticity is obtained by a thicker balloon wall 160, a similar result can be obtained by locally using a different material having a lower elasticity.

[0078] FIG. 6 illustrates a further example of a balloon according to an embodiment of the present invention. FIG. 6 part (A) illustrates that the balloon wall 160 may extend into a fluid inlet / outlet in the vessel wall . This again results in a higher risk for rupture of the balloon wall 160. FIG. 6 part (B) illustrates that a balloon wall 160 having a local region 420 which is less elastic near the fluid inlet / outlet 410 may avoid that the balloon wall extends into this inlet / outlet 410, thus avoiding this risk of rupture. This local region 420 with decreased elasticity can again be obtained in different manners, one example being by using a balloon wall that has a local region with higher thickness, another example being by using an local region in the balloon wall made of a different material having structural properties resulting in a lower elasticity.

[0079] In other examples, as illustrated in FIG. 7 and FIG. 8, energy handling systems are considered that are based on multiple interconnected heat exchange units, such as for example based on 4 heat exchanging units as shown in FIG. 7 or based on 8 heat exchanging units as shown in FIG.

[0080] 8 for obtaining an energy handling system that can operate in a continuous mode. The heat exchange units thereby are interconnected two-by-two, as also described in international patent application WO2023 / 148229 by KilianNRGs. In the present example, valves that are used between the two-by-two interconnected heat exchange units are omitted, since the balloon wall can be used for hermetically sealing the fluid inlet / outlet, once the balloon is filled completely in one of the interconnected heat exchange units. In this way less valves are required, rendering the system more cost efficient and less prone to failure. More particularly, FIG 7 shows asystem 1 as described in the second example is shown, but rather than using fluid reservoirs, the HBVI units 710a, 710b are fluidically connected with further HBVI units 710c, 710d via pump / motor systems 720a, 720b. These are arranged similarly as HBVI units 710a, 710b. The HBVI unit 710c, 71 Od each typically may be connected to a heat exchange element 712c, 712d via a circulation pump (not shown explicitly). By controlling the pump / motor system 720a, 720b using a controller 740, the filling of the balloon of the respective HBVI unit 710a in fluidic communication with the balloon of the HBVI unit 710d and the filling of the balloon of the HBVI unit 710b in fluidic communication with the balloon of the HBVI unit 710c can be controlled. In the drawing and for one application envisaged, it is also indicated per HBVI unit if it provides an interface with the environment at high temperature (H) or an interface with the environment at low temperature (C). The environmental temperatures of the HBVI’s are such that each of the pump / motor systems 720a, 720b can operate at one environmental temperature. The latter allows for inducing expansion or compression of the fluid in the space defined between the vessel and the balloon of the HBVI units 710a, 710b, 710c and 710d. By controlling the expansion or compression of the fluid in the space defined between the vessel and the balloon using the controller 740, the way the expansion or compression occurs can be controlled. Further features such as safety valves, sensors and alike may be present, but according to embodiments, no valves are required between the HBVI units that are coupled to each other, since the balloon functions as valve. In FIG. 8, a system 1 is shown based on eight HBVI units. In this system, HBVI units are also interconnected two by two, so as to allow for improved operation and so as to avoid the need for liquid tanks (the balloons of the HBVI operate as liquid tanks or may act as additional HBVI’s).

[0081] The system allows for substantially continuous energy production, e.g. heat in case of a heat pump or e.g. mechanical energy in case of a heat engine. An advantage is that no valves are required between two-by-two coupled HBVI units, since the balloons function as valves. Other standard and optional components may be present as understood by the person skilled in the art.

[0082] In a second aspect, the present invention relates to an energy handling system comprising a vessel and a balloon according to any embodiments of the first aspect. In embodiments, the energy handling system may be configured to store energy by compressing and expanding a fluid within the balloon, thereby enabling energy conversion, storage, and transmission within the system. Other features and characteristics may be as set out in the first aspect.In another aspect, the present invention also relates to a balloon for use in an energy handling system for converting, transmitting or storing energy making use of a vessel and a balloon mounted therein. Such a balloon may be especially suitable for use in an energy handling system as described in European patent application EP4224103 or as described in International patent application WO2023 / 148229, although embodiments are not limited thereto.

[0083] According to embodiments of the present invention, the balloon has a balloon wall, wherein the balloon wall comprises an elastic layer for allowing the balloon to expand in the vessel, and at least one further layer positioned adjacent the elastic layer, the at least one further layer comprising a first barrier layer preventing interaction between a first fluid used in the energy handling system and the elastic layer of the balloon wall. In different examples, the barrier layer may be positioned on a first side of the elastic layer or at the other side of the elastic, on a second side of the elastic layer or a barrier layer may be present

[0084] It is an advantage that one or more barrier layers may be diffusion-limiting or diffusionpreventing hence avoiding that fluid crosses the balloon wall. Such barrier layers may also prevent interaction of a fluid with the elastic material and hence may prevent deterioration of the elastic material of the elastic layer. The one or more barrier layers do not need to be fixed to the elastic layer, but may be fixed thereto.

[0085] FIG. 9 illustrates an example of a balloon according to an embodiment of the present invention, wherein the balloon wall comprises a first barrier layer, an elastic layer and a second barrier layer. The first barrier layer prevents diffusion of the first fluid towards the elastic material of the elastic layer. The elastic layer guarantees the elastic properties of the balloon. The second barrier layer prevents diffusion of the second fluid towards the elastic material of the elastic layer. In FIG. 9, the balloon 160 is shown whereby the balloon wall is built up of a first barrier layer 910, an elastic layer 920 and a second barrier layer 930.

[0086] It is to be understood that although preferred embodiments, specific constructions and configurations, as well as materials, have been discussed herein for devices according to the present invention, various changes or modifications in form and detail may be made without departing from the scope of this invention.

Claims

CLAIMS1. A balloon for use in a energy handling system based on a vessel and a balloon mounted therein, the balloon comprising a balloon wall, wherein the balloon wall includes at least one variation in structural properties inducing a variation in elasticity configured to control the expansion behavior of the balloon at that location.

2. The balloon according to claim 1, wherein the at least one variation in structural properties comprises a local variation in thickness of the balloon wall.

3. The balloon according to claim 2, wherein the local variation in thickness of the balloon wall is an increased thickness of the balloon wall, resulting in a reduced elasticity.

4. The balloon according to claim 3, wherein the local variation of the thickness of the balloon is between 1,1 and 10 times as thick compared to the thickness of the balloon where no local thickening is present.

5. The balloon according to any of the previous claims, wherein the at least one variation in structural properties comprises a local variation in material properties.

6. The balloon according to claim 5, wherein the at least one local variation in material properties is a difference in shore hardness, Young’s modulus, bulk modulus or elastic modulus.

7. The balloon according to any of the previous claims, the balloon having an elongated shape and being configured for mounting the balloon in the vessel at the two extremities of the balloon, wherein the at least one variation in structural properties is positioned at a location where, when the balloon is expanded, the balloon needs to touch the vessel the latest.

8. The balloon according to claim 7, wherein the balloon comprises a gradual variation of structural properties from an extremity of the balloon towards the center of the balloon.

9. The balloon according to any of the previous claims, wherein at least one local thickening is positioned at a location, when the balloon is mounted in the vessel, corresponding to a sharp edge in the vessel wall of the energy handling system.

10. The balloon according to claim 9, wherein the sharp edge is an assembly gap between different components mounted together to form the inner volume of the vessel.

11. The balloon according to any of the previous claims, wherein at least one local thickening is positioned, when the balloon is mounted in the vessel, near a filling hole in the vessel of the energy handling system, allowing to seal, when the balloonis fully expanded, the filling hole whereby the balloon wall is substantially flush with the vessel wall surrounding the filling hole.

12. The balloon according to any of the previous claims, wherein the balloon comprises a plurality of variations in structural properties along the surface of the balloon.

13. A energy handling system comprising a vessel and a balloon according to any one of claims 1 to 12.

14. A energy handling system according to claim 13, wherein the balloon has an elongated shape, the balloon being mounted to the vessel at two extremities of the elongated shape in a pre-tensed manner.

15. The energy handling system according to any of claims 13 to 14,the energy handling system comprises at least two vessels with balloons according to any of claims 1 to 12, the two vessels being fluidically interconnected with each other,wherein the balloons comprise at least one local variation in structural properties configured for hermetically sealing the fluid interconnection between the at least two fluidically interconnected vessels when one of the balloon is completely filled.

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