Heat pipe for embedding in a construction material of a thermally activatable building component, and thermally activatable building component

Abstract

The invention relates to a heat pipe (102) for embedding in a construction material (108) of a thermally activatable building component (100), wherein the heat pipe (102) is rod-shaped and consists of a metal material (202), wherein a working medium (112) is pressure-tightly encapsulated in at least one partial volume (114) of a cavity (110) of the heat pipe, wherein the partial volume (114) is greater than a volume of a liquid phase of the working medium (112), and wherein a boiling point of the working medium (112) is set to a specified working temperature by a pressure in the partial volume (114). The heat pipe (102) is configured to support at least a portion of a force required for the structural dimensioning of the building component (100), wherein a supporting cross-sectional area of the heat pipe (102) is greater than a minimum area required by the force and a strength of the metal material (202).

Description

[0001] Munich, August 21, 2025

[0002] UNIVERSITY OF STUTTGART

[0003] KEPLERSTRASSE 7

[0004] 70174 Stuttgart

[0005] HEAT PIPE FOR EMBEDDING IN A BUILDING MATERIAL OF A THERMALLY ACTIVATED BUILDING COMPONENT AND THERMALLY

[0006] ACTIVABLE BUILDING COMPONENT

[0007] AREA OF INVENTION

[0008] The present invention relates to a heat pipe for embedding in a building material of a thermally activated building component, and to a thermally activated building component with at least one such embedded heat pipe.

[0009] BACKGROUND OF THE INVENTION

[0010] A hydraulic system can be used to regulate the temperature of a building. A hydraulic system is a self-contained system that is integrated into the building and has no function other than temperature control. Parts of the hydraulic system can be located within the building's structural components.

[0011] The hydraulic system has at least one fluid circuit through pipes and / or hoses. Parts of the fluid circuit can be divided into a

[0012] The KU:GR building component may be embedded. If the hydraulic system is configured as underfloor heating, wall heating, or ceiling heating, the pipes and / or hoses may be arranged on and / or along a surface of the building component. Particularly in the case of underfloor heating, the pipes and / or hoses may be embedded in a screed. The hydraulic system may also be configured for component activation. In this case, the pipes and / or hoses are embedded directly into the building component, in addition to any reinforcement elements.

[0013] A fluid circuit transports thermal energy from a heat source to a heat sink. This thermal energy is transferred sensibly, meaning through temperature changes in a fluid such as water. At the heat source, the fluid absorbs thermal energy and heats up. At the heat sink, the fluid releases the thermal energy and cools down. The fluid circuit can generally be controlled by at least one pump, at least one mixer, and / or at least one control valve. If the fluid is warmer than its surroundings, thermal energy is added to the surroundings. If the fluid is colder than the surroundings, thermal energy is removed from the surroundings. Thus, the hydraulic system can supply or remove thermal energy from the surroundings or the building. The building can be heated or cooled. A boiler, for example, can be used as the heat source.An air conditioner, for example, can be used as a heat sink.

[0014] Thermally activated building components can be used to create balanced climatic conditions in a building by maintaining a constant target temperature within the building component. Due to its large mass, the building component can buffer temperature fluctuations. If the room temperature is higher than the target temperature, the building component acts as a heat sink. If the room temperature is lower than the target temperature, the building component acts as a heat source. Alternatively, thermal energy can also be transferred through a phase change of a transfer medium. For example, the transfer medium can absorb large amounts of thermal energy by changing from a liquid to a vapor phase without a significant temperature change. This thermal energy can then be released again by the transfer medium by changing back from the vapor phase to the liquid phase without a significant temperature change.This can be described as latent heat transfer.

[0015] Latent heat transfer is used, for example, in heat pumps. Here, the transfer medium evaporates in an evaporator, absorbing heat, and condenses in a condenser, releasing heat.

[0016] A compressor is located between the evaporator and the condenser, increasing the pressure between them. This pressure increase causes heat to be released at a higher temperature than the temperature at which it is absorbed. A throttle valve is then located between the condenser and the evaporator to reduce the pressure back down to a lower level, allowing heat to be absorbed at a lower temperature.

[0017] Generally, at least the condenser is designed as a heat exchanger within the hydraulic system. For heat transfer, the heat exchanger requires a temperature difference between the condensing transfer medium and the fluid in the hydraulic system. The heat pump provides a higher temperature level than is actually necessary for heating the building.

[0018] Alternatively, the condenser pipes can be embedded directly into the building material of the component. In particular, the pipes can be embedded in the screed as part of underfloor heating. This allows the heat energy in the condenser to be transferred directly to the desired temperature level for the building component. Direct condensation eliminates the need for a heat exchanger's temperature differential. The temperature level is directly controlled by the compressor pressure.

[0019] SUMMARY OF THE INVENTION AND ADVANTAGEOUS EXECUTIONS

[0020] It was recognized that there may be a need for an improved method of temperature control for building components. In particular, the building component should be able to be temperature-controlled with minimal material and equipment requirements, with high reliability, high energy efficiency, and / or at relatively low cost.

[0021] Such a need can be met by the subject matter of one of the independent claims. Advantageous embodiments are set out in the dependent claims and in the following description and illustrated in the figures.

[0022] According to a first aspect of the invention, a heat pipe for embedding in the building material of a thermally activated building component is presented. The heat pipe is rod-shaped and made of a metal material. A working medium is pressure-tightly encapsulated in at least a partial volume of a cavity within the heat pipe. This partial volume is larger than the volume of the liquid phase of the working medium. The boiling point of the working medium is set to a predetermined operating temperature by a pressure within the partial volume. The heat pipe is configured to bear at least a portion of the force required for the structural design of the building component. For this purpose, the load-bearing cross-sectional area of ​​the heat pipe is intended to be larger than the minimum area required by the force and the strength of the metal material.

[0023] According to a second aspect, a thermally activated building component is presented. In this component, at least one heat pipe is at least partially embedded in a building material of the component. The heat pipe is rod-shaped and made of a metal material, wherein a working medium is pressure-tightly encapsulated in at least a partial volume of a cavity within the heat pipe. This partial volume is larger than the volume of a liquid phase of the working medium, and the boiling point of the working medium is set to a predetermined operating temperature by a pressure within the partial volume. Preferably (but not necessarily), the heat pipe is configured with the features of the heat pipe according to an embodiment of the first aspect of the invention and can therefore fulfill a dual static and thermal function, as described below.

[0024] Possible features and advantages of embodiments of the invention can be considered, among other things and without limiting the invention, as being based on the ideas and findings described below.

[0025] In short, and without limiting the invention in any way, the underlying principle of the heat pipe presented herein can be seen as the integration of a heat pipe for latent heat transfer into a building component. The heat pipe runs at least predominantly within the building component. For this purpose, the heat pipe is embedded in a building material of the building component before the material hardens. The heat pipe is a completely self-contained system and requires no external energy input for heat transfer other than a small temperature difference. The heat pipe can enable a homogeneous temperature distribution within the building component. Due to latent heat transfer, the heat pipe exhibits a high heat transfer capacity with minimal material usage.

[0026] The heat pipe is designed to efficiently transport heat along its longitudinal axis. Inside the heat pipe, thermal energy is transferred primarily in vapor form. A working fluid evaporates during a first phase change within the heat pipe, absorbing thermal energy in the form of enthalpy of vaporization. The vapor is transported along the heat pipe and then condenses again during a second phase change. In this second phase change, the working fluid releases the thermal energy as enthalpy of condensation. The temperature of the working fluid remains approximately constant during the phase changes. The working fluid is tightly enclosed within the heat pipe. In particular, the working fluid is hermetically sealed within its volume. The heat pipe does not require a pump or compressor. The working fluid evaporates where thermal energy is supplied and condenses where thermal energy is removed.Where the working fluid evaporates, an evaporation zone forms. Where the working fluid condenses, a condensation zone forms. The evaporated working fluid is transported in the heat pipe by a pressure gradient generated by evaporation and condensation. This pressure gradient arises because the density of the working fluid changes significantly during evaporation and condensation. During evaporation, the volume per unit mass increases. Conversely, the volume per unit mass decreases during condensation. This creates an overpressure in the evaporation zone and an underpressure in the condensation zone. The vaporous working fluid is thus forced out of the evaporation zone and drawn into the condensation zone. The condensed working fluid flows or creeps back from the condensation zone to the evaporation zone via capillary action and / or gravity, where the cycle begins again.The cycle requires no externally supplied drive energy, except for a small temperature gradient. The temperature at which the phase change occurs is determined by the boiling point of the working fluid. The boiling point is defined by a pressure or vacuum in the closed partial volume of the heat pipe. The lower the pressure, the lower the boiling point typically is. Depending on the application-specific thermal requirements, various pure media or mixtures of media with azeotropic or non-azeotropic properties can be used as the working fluid. When using mixtures as the working fluid, a gradual evaporation / condensation over a wider temperature range in the heat pipe can be achieved, if required, compared to pure media.This can lead to a reduction in the temperature difference between the heat source / heat sink and the heat pipe, thereby improving heat transfer over a wider temperature range and increasing the overall thermal efficiency of the system. If only a portion of the cavity is to be designed as a heat pipe, this portion can, for example, be pinched off or plugged to create the partial volume. In this partial volume, in addition to the liquid phase, a portion of the working fluid is also present as a gaseous phase. A reduced pressure or (partial) vacuum can be established in this partial volume to achieve a low boiling point. The boiling point corresponds to the evaporation temperature and is equal to the condensation temperature of the working fluid. The boiling point essentially corresponds to the operating temperature at which heat energy can be absorbed and released.For sensible heat transfer through the metal material of the heat pipe, a temperature difference is required. Therefore, the external temperature of the heat pipe at which the working fluid inside the heat pipe evaporates is slightly higher than the evaporation temperature. Conversely, the external temperature at which the working fluid condenses in the heat pipe is slightly lower than the condensation temperature. The temperature gradient required for the transfer of heat energy results from these two different external temperatures of the evaporation and condensation zones.

[0027] The heat pipe can be made partially or entirely of, for example, copper or aluminum. The metal material can have a tensile strength of at least 40 N / mm². Alternatively, the heat pipe can also be made partially or entirely of iron. In particular, an external portion of the heat pipe that comes into contact with the building material can be made of the metal material, preferably iron.

[0028] A building component can be, for example, a floor slab, a ceiling slab, a wall, a beam, or a column. The shape of the building component can be defined, for example, by formwork, an excavated cavity, and / or at least one other building component. The building material can be mixed as a dispersion from a binder and aggregates with liquid. The flowable building material fills the form and takes on its contour. The building material then hardens and retains its shape. As it fills the form, the building material also flows around and embeds at least one heat pipe. The building material can be based on organic or inorganic binders and can be, for example, cement-based, gypsum-based, or polymer-based.

[0029] The building component can have a mechanically load-bearing or stabilizing function within the building it encompasses. The building component can be supplied as a prefabricated element. Alternatively, it can be cast on-site. The building component can also be supplied as a semi-prefabricated element. In this case, additional heat pipes or standard reinforcement elements can be added on-site and then embedded in the building material. Semi-prefabricated elements allow for particularly good, precise, and / or easy alignment of the heat pipes within the building component. Despite this ease of alignment, semi-prefabricated elements are easily transportable and enable rapid construction progress.

[0030] The building component can be reinforced with steel reinforcement elements. These reinforcement elements can be referred to as reinforcing steel or reinforcing bars, rebar, reinforcing steel or reinforcing iron, concrete reinforcing steel, or generally as structural steel. The reinforcement elements exhibit significantly higher strength, particularly higher tensile strength, than the building material. For reinforcement purposes, the reinforcement elements can be arranged within the building material in such a way that they primarily bear tensile forces arising from the structure, while the building material is predominantly subjected to compressive forces. As an alternative to steel, reinforcing fibers, such as carbon fibers, can also be used. The reinforcement elements are generally rod- or grid-shaped. Grids can also be referred to as mats.The reinforcement elements are embedded in the liquid building material and, ideally, completely encased so that they are not exposed on any surface of the building component. The building material then hardens. The combination of steel and concrete is advantageous because there are only minimal differences between the coefficients of thermal expansion of steel and hardened concrete. The heat pipe is configured to bear at least a portion of the force required for the structural design of the building component. For this purpose, the load-bearing cross-sectional area of ​​the heat pipe can be larger than the minimum area required by the force and the strength, particularly the tensile strength, of the metal material.

[0031] The heat pipe can therefore be used as a reinforcement element in the building component. The metal material can be, in particular, steel. A load-bearing cross-sectional area can be provided by the wall thickness of the heat pipe. Mechanical forces acting on the heat pipe are transferred around the cavity via the wall thickness.

[0032] The heat pipe presented here thus fulfills a dual function as reinforcement and as a heat transfer device. In other words, the heat pipe has a mechanical and thermal dual function, being designed both to mechanically stabilize the building component and to transport heat within the building component. In particular, the presented heat pipe can be used for the thermal activation of the building component. Outside of a section designed as a heat pipe, the reinforcement element can, for example, be designed as a solid rod.

[0033] The following details and advantages of possible designs for the described heat pipe are given below.

[0034] The heat pipe is preferably designed to be mechanically stable enough to serve as reinforcement for the surrounding building material. For this purpose, the heat pipe has a load-bearing cross-sectional area that is sufficiently large to absorb forces typically encountered in reinforced building components. For example, the heat pipe can partially absorb forces resulting from the static and / or dynamic design. The cross-sectional area of ​​the rod-shaped, internally hollow heat pipe, for instance, can contribute to the required degree of reinforcement.

[0035] The heat pipe can be part of a reinforcement grid. This reinforcement grid can be welded and referred to as a reinforcement mat or reinforcement mesh. Alternatively, the reinforcement grid can be tied together with non-load-bearing wire connections. The reinforcement grid can include one or more of the heat pipes described herein, which have a dual mechanical and thermal function, as well as reinforcing bars running transversely to them. The heat pipes presented here can also be arranged transversely within the reinforcement grid.

[0036] The metal material can be steel, whose strength contributes to the load-bearing capacity and serviceability.

[0037] The heat pipe can have, at least in sections, a surface serration for interlocking with the building material. This serration can be designed with radially outwardly projecting structures and / or radially inwardly recessed structures. The serration can enable mechanical interlocking between the heat pipe and the building material. It can also increase the surface area of ​​the heat pipe, which can improve heat transfer. The serration can, for example, be rib-like. It can be oriented essentially transversely, possibly perpendicularly, to a longitudinal direction of the heat pipe. This allows the serration to transmit forces particularly well in the longitudinal direction between the heat pipe and the surrounding building material. Finally, the serration can be formed integrally with the metal material of the heat pipe.Alternatively, the heat pipe can be designed as a smooth pipe with welded-on structures, such as rings and / or knobs.

[0038] A capillary structure can be arranged within a portion of the volume. At least a portion of the liquid working medium can be bound within this capillary structure. A capillary structure can be described as a wick. The capillary structure can include structural elements, such as wires or foils, arranged at very close intervals. This creates capillaries between the structural elements, which, through capillary action, attract liquid and can even lift it against gravity. Evaporation in the evaporation zone additionally generates a negative pressure in the liquid, which causes flow through the capillary structure to equalize the negative pressure. This allows the heat pipe with the capillary structure to function independently of gravity. The evaporation zone can therefore also be located above the condensation zone. A heat pipe with a capillary structure can be called a heat pipe.Alternatively, the heat pipe can be designed without a capillary structure. In this case, the heat pipe can be described as a thermosiphon, in which the liquid working medium flows back to the evaporation zone solely by gravity.

[0039] The partial volume can be isolated by a reversibly opening and closing shut-off device. This shut-off device can be, for example, a valve or a screw. The shut-off device allows for monitoring and, if necessary, adjustment or restoration of the pressure within the partial volume of the heat pipe. Therefore, servicing of the heat pipe can be performed using the shut-off device. If necessary, the operating temperature can also be subsequently changed by altering the pressure. The heat pipe can also be adapted to a different application or to a building component optimized for a specific application or operating conditions by selecting a different working medium and / or a different capillary structure. For example, the working medium can be changed for a change of use of the building and / or to increase efficiency.

[0040] The cavity can extend to at least one end of the heat pipe. The shut-off device can be located near the end. The end can be located outside the building material. Thus, the shut-off device can be located outside the building material of the component. This allows the shut-off device to be accessible from the outside. The cavity can be lined with a non-ferrous metal other than the metallic material, at least in the area of ​​the pressure-tight section. The heat pipe, including the cavity, can be designed as a bimetallic pipe. An external metallic material can be, in particular, steel. A lining can be inserted into the cavity of the heat pipe as a tube. The non-ferrous metal can be, for example, aluminum or copper, or an alloy or mixture of these highly thermally conductive metals. The working fluid can be aggressive towards the steel material. The non-ferrous metal can be insensitive to the working fluid.The lining wall can be thinner than the outer metal material. The lining can also protrude from the heat pipe as a branch. In this case, the branch can protrude from the building component, and the heat pipe can continue within the building component. The shut-off device can be located at the branch. The heat pipe can pass through the building material via the branch and transmit forces.

[0041] The following details and advantages of possible designs for the described building component are given below.

[0042] In its intended final position, the building component may have at least a portion of its volume, comprising a certain segment of the rod-shaped heat pipe, oriented at an angle that deviates from the parallel to the surface of the building component. This deviation may be, for example, greater than 0.5°, greater than 1°, greater than 1.5°, or greater than 2°, but preferably less than 10°, less than 5°, or less than 3°. In the installed state of the building component, this angle to the horizontal may form a slope. Due to this slope, the condensed liquid working fluid can flow back towards the evaporation zone by gravity.

[0043] At least a portion of the end section of the heat pipe, comprising a certain amount of the partial volume, can protrude from the building component. This end section can therefore be unembedded. It can also be designed not to be embedded in the building material. The partial volume can be accessible at the end section. For example, the end section can be kept accessible for maintenance purposes. A heat source or heat sink can also be connected to the partial volume at the end section. In this case, either the evaporation zone or the condensation zone can be located at the end section.

[0044] The heat pipe can be bent such that its end runs perpendicular to a main plane of extension of the building component. The end can be angled relative to the building component, for example, at an angle greater than 30°, 45°, 60°, 80°, or, in particular, at an angle of 90° ± 5°. In the case of a building component oriented horizontally as a ceiling or floor, the end can be bent upwards or downwards. In the case of a building component oriented vertically as a wall or column, the end can be bent to the side.

[0045] The building component can be configured to form a floor slab. The end section can protrude from the building component within a wall bearing area. A wall bearing area can be placed on a building wall. A floor surface or a ceiling surface of the building component can be formed between several walls. The end section can protrude from the building component outside of or at the edge of the floor or ceiling surface. In the area of ​​the wall bearing area, additional reinforcement elements of the building component, not configured as a heat pipe, can be provided for connection to the wall. These additional reinforcement elements are then embedded in the wall material and no longer protrude from the building component. The heat pipe can protrude from the building component in front of or behind the wall.In the finished building, the heat pipe can then be concealed, for example, by drywall and / or a maintenance hatch.

[0046] At least one end section of the partial volume or heat pipe can be thermally coupled to a heat sink and / or heat source, which may be controllable. This end section can thus be part of a heat exchanger. If the end section is coupled to a heat sink, it can be the condensation zone. If the end section is coupled to a heat source, it can be the evaporation zone. A heat sink could, for example, be a heat exchanger for preheating domestic hot water. A heat source could, for example, be a heating heat exchanger in a hydraulic system.

[0047] The thermally activated building component can have at least one additional heat pipe. The partial volumes of the heat pipes can have different pressures or operating temperatures. Alternatively or additionally, the partial volumes of the different heat pipes can contain different working fluids. This allows at least one heat pipe to be used for heating and at least one other for cooling.

[0048] At least one of the volumes within one heat pipe can be thermally coupled to a heat sink. At least one of the volumes within the other heat pipe can be thermally coupled to a heat source. For heating, the heat source can be active. For cooling, the heat sink can be active. In each case, the other heat pipe is thermally passive and only transmits forces and essentially no heat.

[0049] The thermally activated building component can have at least one additional heat pipe. The heat pipes can be axially connected to each other to transmit forces between them. For this purpose, the heat pipes can be mechanically coupled or at least adjacent to one another. Heat pipes can have a functionally limited maximum length. Connected heat pipes can span large distances between wall bearing areas. The possible span can essentially be doubled or multiplied. The individual volumes can be connected or not. The heat pipes can, for example, be bolted or welded together.

[0050] The building component can be configured to form a floor slab. The heat pipe can be part of the field reinforcement or support reinforcement of the floor slab. Field reinforcement can be located on the underside of the floor slab. This allows the field reinforcement to be positioned close to the slab surface. In this way, the heat pipe functions similarly to a ceiling heating system and is therefore ideally suited for cooling. Support reinforcement can be located on the top side of the floor slab. This allows the support reinforcement to be positioned close to the floor surface, analogous to underfloor heating. Alternatively, the heat pipe can perform both functions regardless of its location, possibly even in the same position.

[0051] It should be noted that possible features and advantages of embodiments of the invention are described herein partly with reference to a heat pipe designed according to the invention and partly with reference to a building component according to the invention. A person skilled in the art will recognize that the features described for individual embodiments can be appropriately transferred, adapted, and / or exchanged in an analogous manner to other embodiments in order to arrive at further embodiments of the invention and potentially synergistic effects.

[0052] BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Advantageous embodiments of the invention are further explained below with reference to the accompanying drawings, whereby neither the drawings nor the explanations are to be interpreted as limiting the invention in any way.

[0054] Fig. 1 shows a section of a building with a building component according to an exemplary embodiment.

[0055] Fig. 2 shows a sectional view of a heat pipe according to an example design.

[0056] Fig. 3 shows a representation of a reinforcement grid with several heat pipes according to an exemplary embodiment.

[0057] Fig. 4 shows a spatial representation of a vertical building component according to an exemplary embodiment. The figures are schematic only and not to scale. Identical reference numerals in the different drawings denote identical or equivalent features.

[0058] DESCRIPTION OF ADVANTAGEOUS EXECUTION FORMS

[0059] Fig. 1 shows a partial sectional view of a building with a building component 100 according to an exemplary embodiment. Here, the building component 100 forms a floor slab of the building. The building component 100 is mechanically reinforced by at least one heat pipe 102 according to the approach presented here. The heat pipe 102 is rod-shaped and runs along the building component 100 between a slab surface 104 and a floor surface 106 of the building component 100. The heat pipe 102 has a dual function. In addition to mechanical reinforcement, which, for example, in a building component 100 constructed of concrete, can act similarly to reinforcement, the heat pipe 102 enables latent heat transfer within the building component 100.

[0060] For mechanical reinforcement, a load cross-section of the heat pipe 102 is made of a steel material and it is embedded in a building material 108 of the building component 100.

[0061] The heat pipe 102 is configured for latent heat transfer. For this purpose, the heat pipe 102 has a tubular cavity 110 in at least one section. A working medium 112 is enclosed in the cavity 110. The pressure in the cavity 110 is set such that the boiling point of the working medium 112 is at the desired operating temperature.

[0062] In one embodiment, the heat pipe 102 is designed as a tube from one end to the other. The tube is tightly sealed at two points. Between these two points is at least a partial volume 114 of the tube. The working medium 112 is enclosed within this partial volume 114.

[0063] In an alternative embodiment not shown, at least one end region of the heat pipe 102 is designed as solid material without a cavity. Thus, the cavity 110 extends only along a partial section of the heat pipe 102.

[0064] In one embodiment, a shut-off device 118 is arranged at least at one end 116 of the partial volume 114. The shut-off device 118 is arranged in an accessible manner. For example, the shut-off device 118 can be arranged in a box integrated into the building component 100. The box can also be used for other installation purposes. The shut-off device 118 is a valve. The shut-off device 118 can be opened and closed again. The pressure in the partial volume 114 can be checked via the shut-off device 118, for example, as part of routine maintenance, and, if necessary, readjusted to the desired value. The pressure can also be changed via the shut-off device 118, and thus a different operating temperature of the heat pipe 102 can be set. Alternatively or additionally, the working medium 112 can be exchanged via the shut-off device 118 to obtain different properties of the heat pipe 102.

[0065] In one embodiment, the end 116 of the partial volume 114 is not embedded in the building material 108 of the building component 100 and protrudes from the building component 100 with the shut-off device 118. The end 116 can, for example, protrude into a maintenance shaft of the building.

[0066] In one embodiment, the end 116 is bent transversely to a main direction of extension of the heat pipe 102 and protrudes from the base surface 106 of the building component 102 with the shut-off device 118. The end 116 protrudes from the base surface 106 close to a wall bearing area 120 of the building component 102. The end 116 is arranged close to a wall 122 erected on the building component 102 in the wall bearing area 120. For example, the end 116 is arranged in a niche in the wall 122. The niche can be closed by a maintenance door 124 or a maintenance hatch.

[0067] When heat energy 128 is supplied to the heat pipe 102 by a heat source 126, the liquid working medium 112 heats up. The temperature of the working medium 112 increases according to its specific heat capacity and the amount of heat supplied by the heat source 126. When the working medium 112 reaches its boiling point, which is determined by the pressure in the partial volume 114, its temperature remains constant and the working medium 112 begins to evaporate. An evaporation zone 130 is formed. The enthalpy of vaporization of the working medium 112 and the amount of heat supplied determine how much vapor 132 is produced. Since the enthalpy of vaporization is many times higher than the heat capacity, a very large amount of heat energy 128 can be absorbed with a small amount of working medium 112.

[0068] The resulting steam 132 moves out of the evaporation zone 130 along the cavity 110 in the heat pipe 102. In doing so, the steam 132 transports the heat energy 128 to a point in the partial volume 114 where the surface temperature of the partial volume 114 is lower than the boiling point of the working medium 112. There, a condensation zone 134 forms in the heat pipe 102. In the condensation zone 134, the steam 132 condenses and releases an amount of heat corresponding to the condensation enthalpy of the working medium 112 and the amount of condensed steam. The condensation enthalpy is equal to the evaporation enthalpy. If the heat energy 128 is not dissipated, the surface heats up due to the supplied heat energy 128, and condensation ends when the surface reaches the boiling point.

[0069] In one embodiment, a heat sink 136 is thermally coupled to the heat pipe 102 to form a targeted condensation zone 134. The condensation zone 134 is located in the region of the end 116 of the partial volume.

[0070] 114 arranged. The heat sink 136 can, for example, be a domestic hot water preheater before the building's hot water preparation.

[0071] During condensation in the condensation zone 134, the working medium 112 becomes liquid again. The working medium 112 flows as a liquid film 138 and / or as liquid droplets along the partial volume 114 back to the evaporation zone 130, where it evaporates again as long as heat energy 128 is supplied.

[0072] In one embodiment, the heat pipe 102 is arranged at a position 140 deviating from the parallel to the surface of the building section 100, wherein the deviation is, for example, more than 0.5°, more than 1°, more than 1.5°, or more than 2°, but preferably less than 10°, less than 5°, or less than 3°. Due to the slope 140, the evaporation zone 130 is lower than the condensation zone 134. Liquid working fluid 112 flows back from the condensation zone 134 to the evaporation zone 130 due to gravity and the slope 140.

[0073] In one embodiment, a capillary structure 142 is arranged at least partially within the partial volume 114. The capillary structure 142 acts like a wick and transports liquid working medium 112, even against gravity, from the condensation zone 134 to the evaporation zone 130.

[0074] In one embodiment, a plurality of heat pipes 102 with the dual function described here are arranged in the building component 100. The heat pipes 102 are arranged essentially parallel to one another, and additional reinforcing steel bars 144 without a dual function are arranged transversely to them. The heat pipes 102 and the reinforcing steel bars 144 thus form a reinforcement grid 146. The reinforcement grid strengthens the building component 100 longitudinally and transversely. The latent heat transfer functions only in one direction along the heat pipes 102 with encapsulated working medium 112. Alternatively, heat pipes 102 can also run transversely. The heat transfer then functions both longitudinally and transversely.

[0075] Fig. 2 shows a sectional view of a heat pipe 102 according to an exemplary embodiment. The heat pipe 102 essentially corresponds to the heat pipe in Fig. 1. Here, the heat pipe 102 is shown in more detail.

[0076] In one embodiment, the cavity 110 is lined with a non-ferrous metal 200. The non-ferrous metal 200 has a significantly lower strength than the metal material 202 of the load-bearing cross-section of the heat pipe 102 and therefore does not contribute much to the overall strength of the heat pipe 102. The non-ferrous metal 200 has different chemical properties than the metal material 202. Therefore, a working medium 112 can be used that would otherwise attack the metal material 202.

[0077] In one embodiment, the capillary structure 142 has a vapor channel 204 running along the heat pipe 102. The vapor channel 204 is a continuous recess that does not exert any capillary action on the liquid working medium 112. The working medium 112 is therefore not drawn into the vapor channel 204 by capillary forces. The liquid working medium 112 is located approximately entirely within the capillary structure 142. The vapor 112 can flow through the vapor channel 204 to the condensation zone with low flow resistance. In the evaporation zone, the working medium evaporates from the capillary structure 142 into the vapor channel 204.

[0078] In one embodiment, the heat pipe 102 has a toothed structure 206 on its outer surface. The toothed structure 206 consists of protrusions and / or depressions. The toothed structure 206 creates a positive-locking connection to the building material. This positive lock remains in place even if the frictional connection between the heat pipe 102 and the building material weakens. This allows for the continuous transmission of high tensile forces between the heat pipe 102 and the building material. Fig. 3 shows a representation of a reinforcement grid 146 according to one embodiment. The reinforcement grid 146 is lattice-shaped and essentially corresponds to the reinforcement grid in Fig. 1.

[0079] In one embodiment, the heat pipes 102 are arranged approximately 20 centimeters apart from each other.

[0080] In one embodiment, the heat pipes 102 are shorter than the reinforcing steel bars 144. The reinforcing steel bars 144 are aligned longitudinally within the reinforcement grid 146. The heat pipes 102 are aligned transversely within the reinforcement grid 146. For example, the heat pipes 102 are 350 centimeters long, while the reinforcing steel bars 144 are 500 centimeters long.

[0081] In one embodiment, the ends 116 of the heat pipes 102 are bent upwards along an edge of the reinforcement grid 146. Here, the ends 116 are bent upwards by approximately 30 centimeters.

[0082] In one embodiment, the reinforcing steel bars 144 are arranged as the lower reinforcement of the reinforcement grid 146.

[0083] Fig. 4 shows spatial representations of building components 100 according to exemplary embodiments. The building components 100 essentially correspond to the building component in Fig. 1. One building component 100 is designed as a ceiling slab 400, as in Fig. 1. Other building components 102 are designed as walls 122 and as columns 402. In contrast to the representation in Fig. 1, the building components 100 have three-dimensional reinforcements, which are at least partially designed as heat pipes 102 according to the approach presented here.

[0084] In the slab 400, the reinforcement is designed as field reinforcement 404 and support reinforcement 406. The field reinforcement 404 is embedded in the building material 108 near the slab surface 104. The support reinforcement 406 is embedded in the building material 108 near the floor surface 106. Both reinforcements are designed as a reinforcement grid 146. Within this grid 146, a heat pipe 102 and a reinforcing steel bar 144 are arranged alternately, parallel to each other. The heat pipes 102 of the field reinforcement 404 are bent upwards towards the floor surface 106 and protrude from the floor surface 106. The heat pipes 102 of the support reinforcement 406 are bent downwards towards the slab surface 104 and protrude from the slab surface 104.

[0085] In one of the walls 122 and the column 402, the vertical reinforcements are designed as thermal pipes 102, while the horizontal reinforcements alternate between thermal pipes 102 and reinforcing steel bars 144. In the wall 122, the ends 116 of the vertical thermal pipes 102 are bent to the opposite side and protrude there, while in the column 402, the ends 116 of the vertical thermal pipes 102 protrude from the building material 108 on the respective side of the column 402. The horizontal reinforcements are ring-shaped and do not protrude from the building material 108.

[0086] In the second wall 122, the horizontal reinforcements are designed as heat pipes 102, and the vertical reinforcements alternate between heat pipes 102 and reinforcing steel bars 144. Here, the ends 116 of the horizontal heat pipes 102 protrude from the wall 122 on the opposite side, while the vertical reinforcements are ring-shaped and without protruding ends.

[0087] Possible embodiments of the invention are summarized below or presented using slightly different wording.

[0088] A passively activated concrete core panel with a dual thermal and structural function is presented. Thermal building equipment and thermally activated ceilings / floors for room temperature control generally only have a thermal function. The structural implementation usually depends on the operating principle of heat transfer (radiation / convection). Radiant cooling ceilings and thermally activated building components are generally closed systems. Temperature control is primarily achieved through pipe systems made of copper, other metals (alloys), or plastics, through which water flows, driven by a pump. Furthermore, these actively operated cooling systems, which utilize primary energy, only have a thermal function.

[0089] Thermal building systems generally require a boiler or chiller for heating and cooling, as well as a sufficiently powerful pump to distribute the temperature-controlled fluid throughout the building. This is associated with increased CO2 emissions and / or high primary energy consumption.

[0090] The approach presented here enables energy-efficient heating and cooling of buildings through passive operation (without pump operation for circulation of the temperature control fluid) using heat pipes and a dual function (thermal / static) of the building's climate control technology as reinforcement.

[0091] Closed two-phase thermosiphons / heat tubes are passively operating heat transfer systems. They typically consist of an evacuated tube containing a heat transfer fluid under saturation conditions, divided into three zones (heating zone, adiabatic zone, and cooling zone). In the heating zone, the heat transfer fluid evaporates, absorbing heat through the heat input. Driven by a pressure gradient, the vapor flows through the adiabatic zone into the cooling zone, where it condenses, releasing heat through latent heat. The condensate then passively flows back into the heating zone via gravity or capillary action. Operating ranges extend from cryogenic temperature ranges of approximately 10 K to U0020P-WG.

[0092] - 24 -

[0093] High-temperature applications with temperatures exceeding 2000 K. For room temperature control, both the heating and cooling zones can be located in the ceiling or floor area. This allows for both heating and cooling. The evaporation of the heat transfer fluid creates a cooling effect. In cooling mode, the energy input for evaporation is supplied, for example, by the use of the room, such as waste heat from people or machines. The condensation waste heat in the cooling zone can be used, for example, by routing it through a water pipe for preheating drinking water. Since the heat pipes can be made of structural steel, they can also serve as reinforcement, further increasing the efficiency and sustainability of the system. They can replace or supplement the structurally necessary reinforcement of the reinforced concrete slab.

[0094] The approach presented here allows the thermally activated concrete slab to passively regulate building temperature year-round without a chiller or boiler. It requires no pumping system (pump, plastic tubing) for transporting the heat transfer fluid and no additional reinforcement when using structural steel pipes. Furthermore, the latent heat utilization of the thermally activated concrete slab allows for the creation of a very homogeneous temperature field with low required temperature gradients within the slab, resulting in high energy efficiency and comfort.

[0095] By eliminating the need for heating and cooling systems, pumps, and reinforcement, the sustainability of concrete-ceramic building components for climate control can be significantly increased through savings in raw materials and production. Furthermore, primary energy consumption during operation can be drastically reduced, and investment costs can also be substantially lowered. An additional advantage is that the latent heat absorption or release of the heat pipes allows for near-isothermal temperature control of the surface being cooled or heated. Moreover, compared to sensible heat transfer in conventional heating / cooling systems, a significantly larger amount of heat can be transported at low driving temperature differences due to the evaporation / condensation enthalpy of the heat transfer medium in the heat pipe.

[0096] Finally, it should be noted that terms such as "comprising," "encompassing," etc., do not exclude other elements or steps, and terms such as "a" or "an" do not exclude a plurality. Furthermore, it should be noted that features or steps described with reference to one of the above embodiments may also be used in combination with other features or steps of other embodiments described above. Reference numerals in the claims are not to be construed as

[0097] To be considered a limitation.

[0098] Reference symbol list

[0099] 100 building components

[0100] 102 Heat pipe

[0101] 104 ceiling area

[0102] 106 floor area

[0103] 108 Building materials

[0104] 110 cavity

[0105] 112 Working medium

[0106] 114 sub-volumes

[0107] 116 End

[0108] 118 Ab shut-off device

[0109] 120 wall mounting area

[0110] 122 Wall

[0111] 124 Maintenance door

[0112] 126 Heat source

[0113] 128 Thermal energy

[0114] 130 evaporation range

[0115] 132 steam

[0116] 134 Condensation area

[0117] 136 Heat sink

[0118] 138 Liquid film

[0119] 140° slope

[0120] 142 Capillary structure

[0121] 144 reinforcing steel bars

[0122] 146 reinforcement grid

[0123] 200 Non-ferrous metal

[0124] 202 steel material, metal material

[0125] 204 Steam duct

[0126] 206 Interlocking structure 400 Ceiling

[0127] 402 support

[0128] 404 Field reinforcement 406 Support reinforcement

Claims

- 28 - Claims 1. Heat pipe (102) for embedding in a building material (108) of a thermally activated building component (100), wherein the heat pipe (102) is rod-shaped and made of a metal material (202), wherein a working medium (112) is pressure-tightly encapsulated in at least one partial volume (114) of a cavity (110) of the heat pipe, wherein the partial volume (114) is larger than a volume of a liquid phase of the working medium (112), and wherein a boiling point of the working medium (112) is set to a predetermined operating temperature by a pressure in the partial volume (114), wherein the heat pipe (102) is configured to bear at least a portion of a force required for the structural design of the building component (100), wherein a load-bearing cross-sectional area of ​​the heat pipe (102) is larger than a minimum area required by the force and a strength of the metal material (202).

2. Heat pipe (102) according to claim 1, wherein the strength of the metal material (202) contributes to the load-bearing capacity and serviceability of the building component.

3. Heat pipe (102) according to one of the preceding claims, wherein the heat pipe (102) has at least sectionally a surface interlocking structure (206) for interlocking with the building material (108).

4. Heat pipe (102) according to one of the preceding claims, wherein a capillary structure (142) is arranged in the partial volume (114), wherein at least a proportion of the liquid working medium (112) is bound in the capillary structure (142).

5. Heat pipe (102) according to one of the preceding claims, wherein the partial volume (114) is shut off by a shut-off device (118).

6. Heat pipe (102) according to claim 5, wherein the cavity (110) extends to at least one end (116) of the heat pipe (102), wherein the shut-off device (118) is arranged in the region of the end (116).

7. Heat pipe (102) according to one of the preceding claims, wherein the cavity (110) is lined at least in the area of ​​the pressure-tight partial volume (114) by a non-ferrous metal (200) different from the metal material (202).

8. Thermally activatable building component (100), wherein at least one heat pipe (102) is at least partially embedded in a building material (108) of the building component (100), wherein the heat pipe (102) is rod-shaped and made of a metal material (202), wherein a working medium (112) is pressure-tightly encapsulated in at least one partial volume (114) of a cavity (110) of the heat pipe, wherein the partial volume (114) is larger than a volume of a liquid phase of the working medium (112), and wherein a boiling point of the working medium (112) is set to a predetermined working temperature by a pressure in the partial volume (114), wherein the heat pipe is preferably designed according to one of claims 1 to 8.

9. Thermally activatable building component (100) according to claim 8, wherein in an intended end position of the building component at least a partial area of ​​the rod-shaped heat pipe (102) comprising a portion of the partial volume (114) is inserted with a position, in particular a slope, (140) deviating from the parallel of the surface of the building component.

10. Thermally activatable building component (100) according to one of claims 8 and 9, wherein at least one end (116) of the heat pipe (102) comprising a portion of the partial volume (114) protrudes from the building component (100).

11. Thermally activatable building component (100) according to claim 10, wherein the heat pipe (102) is bent such that the end (116) extends transversely to a main extension plane of the building component (100).

12. Thermally activatable building component (100) according to one of claims 10 to 11, wherein the building component (100) is configured to form a floor slab and the end (116) protrudes from the building component (100) in a wall bearing area (120) of the floor slab.

13. Thermally activatable building component (100) according to one of claims 8 to 12, wherein at least one end (116) of the heat pipe (102) comprising a portion of the partial volume (114) is thermally coupled to a heat sink (136) and / or heat source (126).

14. Thermally activatable building component (100) according to one of claims 8 to 13, with at least one further heat pipe (102), which is preferably designed according to one of claims 1 to 8, wherein a partial volume (114) of a first of the heat pipes and a partial volume (114) of a second of the heat pipes have different pressures and / or operating temperatures.

15. Thermally activated building component (100) according to one of claims 8 to 14, with at least one further heat pipe (102), which is preferably designed according to one of claims 1 to 8, wherein a partial volume (114) of a first of the heat pipes is thermally coupled to a heat sink (136) and a partial volume (114) of a second of the heat pipes is coupled to a heat source (126).

16. Thermally activatable building component (100) according to one of claims 8 to 15, with at least one further heat pipe (102), which preferably is designed according to one of claims 1 to 8, wherein the heat pipes (102) are axially connected to each other.

17. Thermally activated building component (100) according to one of claims 8 to 16, wherein the building component (100) is configured to form a floor slab and the heat pipe (102) is part of a field reinforcement (404) or support reinforcement (406) of the building component (100).

18. Thermally activatable building component (100) according to one of claims 8 to 17, wherein a mixture of media is used as the working medium, in particular a mixture of media having azeotropic or non-azeotropic material properties.

19. Thermally activatable building component (100) according to one of claims 8 to 18, wherein the working medium and / or a capillary structure within the heat pipe are selected to suit the properties of the building component and / or the conditions prevailing on the building component.

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