WO2020094182A1

WO2020094182A1 - Heat transport unit

Info

Publication number: WO2020094182A1
Application number: PCT/DE2019/100936
Authority: WO
Inventors: Lea Kelbsch
Original assignee: Lea Kelbsch
Priority date: 2018-11-08
Filing date: 2019-10-30
Publication date: 2020-05-14
Also published as: EP3877715A1; DE102018127928A1

Abstract

The invention relates to a heat transport unit (1) which is designed in particular in the form of a flexible heat pipe, comprising an evaporation region (2), a condensation region (3), and a line region (4) which is arranged between the evaporation region (2) and the condensation region (3) and via which thermal energy is transported from the evaporation region (2) to the condensation region (3). The heat transport unit also comprises a fluid (14) which can be found in the evaporation region (2), and the line region (4) consists of two connection lines, wherein evaporated fluid (14') reaches the condensation region (3) from the evaporation region (2) via one of the two connection lines, and the other connection line is used as a return line for condensed fluid (14).

Description

description

title

Heat transport unit

The invention relates to a heat transport unit, which is designed in particular as a flexible heat pipe, according to the preamble of claim 1.

State of the art

Heat pipes are also known under the term "heat pipes". Such heat pipes have an evaporation area, where a fluid used as a heat carrier is evaporated by supplying heat. The vaporous fluid passes through a pipe section to a condensation area, where the vaporous fluid is cooled and condensed. The liquid fluid is led back to the evaporation area via a capillary structure, so that there is a constant heat transport circuit from the evaporation area to the condensation area. Such a heat pipe is known from DE 10 2010 003 893 Al.

The utility model DE 203 20 409 EU discloses a geothermal probe with an inner tube and an outer tube concentrically surrounding the inner tube. Geothermal heat evaporates a fluid in the lower end of the geothermal probe. The gaseous fluid rises in the inner tube and is condensed again by heat being released at an upper end of the geothermal probe. The condensed fluid flows down again through an annular gap between the outer tube and the inner tube.

DE 10 2009 010 897 A1 discloses a control cabinet with a plurality of switching devices arranged in the interior of the control cabinet, in which control cabinet components are cooled by means of heat pipes. Heat pipes are used in the prior art, for example used for cooling microprocessors in equipment cabinets, wherein several computer units with microprocessors can be used as device racks in an equipment cabinet. The cooling in the individual plug-in units can be done quietly and very effectively by using heat pipes, whereby large amounts of heat energy can be dissipated from the inside of the device via the heat pipes. There is no need to use fans, which not only helps to avoid fan noise, but also has the great advantage that fan vibrations in the area of the sensitive electronic components are avoided.

Heat pipes can also be used to transfer heat from an evaporation area to a condensation area against gravity, since the capillary action enables the fluid to be transported back from the condensation area to the evaporation area against gravity. In contrast, there are also heat pipes that are operated by gravity, with the liquid fluid flowing back from the condensation area to the evaporation area due to gravity.

The use of heat pipes is extremely versatile and is in no way limited to applications in the field of micro or power electronics. LED components, rechargeable high-performance batteries (accumulators) or other elements with high heat loss can also be effectively cooled using heat pipes. It is desirable that the circulation circuit between the evaporation area and the condensation area has the highest possible circulation speed, i. H. that as much fluid as possible is transported from the evaporation area to the condensation area and back to the evaporation area per unit of time, whereby an improvement in the heat transfer from the evaporation area to the condensation area is achieved.

The invention has for its object to provide a tubular heat transport unit, which has the function of a heat pipe with high heat transfer performance.

The solution to this problem is obtained with the features of claim 1. The dependent claims have advantageous refinements and developments of the invention. The heat transport unit according to the invention, which has the function of a heat pipe and has an evaporation area and a condensation area connected to it via a line area, has a line area which consists of two connecting lines, with vaporized fluid passing from the evaporation area to the condensation area and over via one of the two connecting lines the other connecting line condensed fluid flows back to the evaporation area. The use of two connecting lines between the evaporation area and the condensation area has the advantage that the cooled fluid flowing back does not get impaired in its flow rate by the evaporated fluid flowing to the condensation area. Tests have shown that with this arrangement a high circulation speed and thus a very effective heat transfer from the evaporation area to the condensation area of the heat transport unit can be achieved.

The heat transport unit according to the invention is in particular tubular or tubular and in particular at least the line area is flexible, so that the heat transport unit can be bent at least in the line area. A flexible pipe area has the advantage that it can be bent without any significant effort. "Without any noteworthy effort" means a bending of the line area without a bending force or in any case with a lower bending force than is required to bend a plastically bendable pipe as a connecting line.

The heat transport unit according to the invention is hermetically sealed, so that a fluid contained as a heat carrier cannot escape and no fluid can enter from the outside. The fluid in the heat transport unit is partly liquid and partly gaseous.

The two connecting lines have different flow resistances for the fluid. Because of the different flow resistances, the vaporized fluid prefers one of the two connecting lines, so that this results in a fluid circuit in the heat transport unit.

The cross-sectional area of a connecting line provided for the conduction of the vaporized fluid from the evaporation area to the condensation area is larger as a connecting line provided for the return of the condensed fluid from the condensation area to the evaporation area. It is thereby achieved that gas bubbles rising in the evaporation area predominantly reach the connecting line which has the larger cross-sectional area during the evaporation process, so that the one connecting line for the transport of the fluid from the evaporation area to the condensation area is specifically specified. The other connecting line is then inevitably used as a return line for the condensed and cooled fluid.

The cross-sectional area of the connecting line provided for the conduction of the vaporized fluid from the evaporation area to the condensation area is preferably at least twice as large as the cross-sectional area of the connecting line provided for returning the condensed fluid from the condensation area to the evaporation area. In particular, the cross-sectional area ratio of the connecting lines is 1.8 ± 0, 1 or 1.8, 0.2 or 2 ± 0, 1 or 2 ± 0.2.

One embodiment of the invention provides that a contact resistance of the connecting line, which is provided for the return of the condensed fluid from the condensation area to the evaporation area, is approximately twice as large as the transition resistance of the connecting line, which is provided for the conduction of the vaporized fluid from the evaporation area to the condensation area . "About" means a contact resistance tolerance of up to 5%, up to 10% or up to 20%. The transition resistance is a flow resistance of the fluid and, if necessary, an additional resistance that the gas bubbles created during evaporation oppose the flow.

One embodiment of the invention provides that a passage width of the connecting line provided for the return of the condensed fluid from the condensation area to the evaporation area is smaller than a diameter of gas bubbles which arise in the evaporation area when the fluid evaporates. The diameter of the gas bubbles can, but need not, be larger than a diameter of the connecting line provided for the conduction of the fluid from the evaporation region to the condensation region. This prevents or at least reduces the entry of the gas bubbles into the connecting line provided for the return line of the condensed fluid. No or only a few, and preferably only small, gas bubbles enter the condensate for the return Fluid provided connecting line, but it displaces ("pump") gas bubbles, which form during boiling and evaporation of the fluid in the evaporation area and burst again, liquid fluid from the evaporation area into the connecting line, which is provided for the conduction of the fluid from the evaporation area to the condensation area is. A "pump effect" is thereby achieved, which effects the fluid circuit from the evaporation area to the condensation area through the one connecting line and back through the other connecting line. The gas bubbles formed during the boiling and vaporization of the fluid in the evaporation area produce a pulsating pressure, which resistance in the connecting line with the smaller flow or the larger cross-sectional area continues more than in the other connecting line, whereby the desired flow direction without check valves or similar control elements and without one Pump, water screw or other fluid drives is reached. Also gas bubbles that flow in the evaporation area to and / or into the connecting line, which is provided for the conduction of the fluid from the evaporation area to the condensation area, "push" liquid fluid in front of it and pump it through the connecting line. This means that heat transfer is possible, at least to a limited extent, even against capillaries, even without capillaries.

An embodiment of the invention provides that the fluid is liquid in the evaporation area of the heat transport unit. When boiling and evaporating, gas bubbles form which also burst again. With this embodiment of the invention, however, with the exception of any gas bubbles, there is no gaseous fluid above the liquid fluid in the evaporation zone.

So that a specific connection line is used for the transport of the evaporated fluid and the other connection line for the backflow of the cooled fluid, a flow resistance element can be arranged in the transition area between one of the two connection lines and the evaporation area. This

Flow resistance element has the effect that gas bubbles rising during the evaporation process do not use the connecting line with the flow resistance element, but instead use the connecting line which is further open for the rising gas bubbles. In this way, for example, an inner hose concentrically lying in an outer hose for transporting the vaporized fluid can be very specifically Condensation area are used so that the cooled fluid flows back from the condensation area through the annular gap between the outer hose and the inner hose back to the evaporation area.

It is particularly advantageous to design the connecting lines between the evaporation area and the condensation area as a flexible double hose line, which preferably consists of an outer hose and an inner hose running in the outer hose. But it can also be one of two flexible, e.g. B. existing side-by-side hose lines can be used, in which case the evaporation area and the condensation area can each be formed as a chamber with two hose connectors.

Such a line connection has the great advantage that the heat transport unit can be easily positioned on the elements of a computer or other device to be cooled, position tolerances being completely unproblematic due to the flexibility of the heat transport unit. Assembly problems, as can occur with the conventional rigid copper heat pipes, are avoided with the flexible heat transport unit according to the invention.

In the heat transport unit, a capillary structure can be provided on the inner wall in the connecting line serving as a return line from the condensation area to the evaporation area, thereby supporting a return transport of the cooled fluid to the evaporation area.

The capillary structure formed in a connecting line can be produced in the extrusion process during the production of the connecting line. This results in a very inexpensive production for the connecting line equipped with the capillary structure.

There is also the possibility of inserting a longitudinal wick or a corresponding other element into the space between an outer tube and an inner tube, which has a capillary effect and thus supports a return transport of the cooled fluid from the condensation area to the evaporation area in this space. A preferred embodiment of the invention provides a backflow throttle in one of the two connecting lines or in both connecting lines. This is generally understood to mean a device which has a lower flow resistance in the intended flow direction than in the opposite direction or which blocks flow in the opposite direction to the intended flow direction. The return flow restrictor effects or in any case favors the intended flow direction in the respective connecting line. The reflux throttle can be, for example, a non-return valve or a non-fully closing or bypassing non-return valve or a device with a comparable effect.

The evaporation area and the condensation area can advantageously consist of a plastic material with high thermal conductivity, wherein a high thermal conductivity can be achieved by using additives with high thermal conductivity. Depending on the area of application of the heat transport unit, the evaporation area and the condensation area can e.g. B. can also be formed as a copper tube closed on one side, the connecting lines then being connected to the open sides of these elements.

The fluid used in the heat transport unit preferably has a low boiling temperature, which can be, for example, at a pressure within the heat transport unit of 1 to 3 bar in a range between 25 ° Celsius and 40 ° Celsius. Depending on the area of application of the heat transport unit, fluids can also be used which have a higher or lower boiling point, which can be between -20 ° Celsius and + 1000 ° Celsius at a pressure of 0.001 to 100 bar.

Such a fluid is known, for example, under the trade name Novec 7000. A low boiling temperature has the advantage that even with low heat development in the area of a component to be cooled, the heat transport and thus the cooling process can be used effectively.

The connecting line provided for the transport of the vaporized fluid can protrude slightly into the space of the evaporation area and deep into the space of the Protrude condensation area. The functionality of the heat transport unit is positively supported both in the evaporation area and in the condensation area. “To protrude deeply into the space of the condensation area” means that the connecting line protrudes into the condensation area up to a distance of at most the diameter of the heat transport unit from one end of the heat transport unit.

All of the features mentioned in the description and / or the drawing can be implemented individually or in any combination in embodiments of the invention. Embodiments of the invention that do not have all but only part of the features of a claim, including the independent claim, are possible.

The invention will be explained in more detail with reference to exemplary embodiments shown in the drawing. Show it:

Figure 1 shows a heat transfer unit according to the invention with a flexible double hose line;

FIG. 2 shows a heat transport unit according to the invention as in FIG. 1, but with a flow resistance element in the transition area between the double hose line and an evaporation area;

Figure 3 is an enlarged view of a portion of the heat transport unit of Figure 2 in the area of the flow resistance element;

FIG. 4 shows a cross section of a double hose line with a capillary structure according to the invention;

FIG. 5 shows a longitudinal section along the sectional plane A-A of FIG. 4;

FIG. 6 shows a cross section of a double hose line with a wick element according to the invention; 7 shows an axial section along the section plane BB of the double hose line from FIG

6;

FIG. 8 shows a schematically illustrated arrangement of heat transport units effective between thermal coupling units according to the invention; and

FIG. 9 shows an axial section of a further heat transport unit according to the invention.

The heat transport unit 1 according to the invention shown in FIG. 1 has the functionality of a heat pipe and has an evaporation area 2 and a condensation area 3 which are connected to one another via a line area 4 for the transmission of thermal energy. The evaporation area 2 can consist of a metal sleeve closed on one side, for example of copper. The condensation area 3 can also be made from a metal sleeve closed on one side. However, there is also the possibility of producing the evaporation area 2 and the condensation area 3 from a plastic material 5 with the best possible thermal conductivity. The sleeves used for the evaporation area 2 and the condensation area 3 are therefore referred to as plastic sleeves 6, 7 by way of example in the following description.

In the exemplary embodiment shown, the line area 4 is formed by a double hose line 8, which consists of an outer hose 9 and an inner hose 10 running concentrically in the outer hose 9. Since an exact concentric arrangement of the outer tube 9 and inner tube 10 is not absolutely necessary, no centering elements are shown in FIG. 1, which, however, could be present in the form of centering webs projecting from the inside of the outer tube 9. 8 annular centering elements could also be used at intervals in the flexible double hose line.

The double hose line 8 is made of a flexible plastic material, so that the heat transport unit 1 can be bent flexibly and at least in the line area 4 and without exertion of force (no force is required as for plastic deformation of the line area 4) and thus the evaporation area 2 and the condensation area 3 in different positions or orientations can be brought. In Figure 1 are a heat source 11 to be cooled is indicated as a circular region with a broken line and a heat emission region 12 is also indicated with a broken circular line. If the heat dissipation area 12 is located at a position other than that shown, it is possible due to the flexible double hose line 8 that the heat transport unit 1 is bent, so that the plastic sleeve 7 forming the condensation area 3 can be brought into thermal conduction contact with the heat dissipation area 12. The heat emission region 12 can have an element with cooling fins made of aluminum or else an element through which a coolant flows.

The function of heat transfer is described below.

With the heat energy emitted by the heat source 11, a fluid 14 located in the evaporation area 2 in the plastic sleeve 6 is heated and brought to the boil and / or evaporation. The vaporous fluid 14 ′ passes through the inner tube 10 in the direction of the arrow 15 to the condensation area 3, which has a lower temperature, so that the evaporated fluid 14 ′ condenses in the condensation area 3 on the inner wall of the plastic sleeve 7 and between the outer tube 9 and the inner tube 10 flows back to the evaporation region 2 in the direction of the arrow 16 as a liquid fluid 14. As long as the heat source 11 continues to supply heat energy in accordance with the arrow directions 13 to the evaporation area 2 and condensation takes place in the condensation area 3, a circulation circuit in accordance with the arrow directions 15, 16 is maintained and thus a constant heat transfer from the heat source 11 to the condensation area 3 or to one Heat emission area 12 performed.

Vaporizable liquids with a low boiling point, which are generally known for such applications in heat pipes or heat pipes, are suitable as the fluid 14. Very good heat transfer results were achieved with a fluid that had a boiling point at approximately 30 ° Celsius. Depending on the area of application, the boiling point of the fluid 14 used can be set at different levels in different heat transport units, a range between 25 ° C. and 80 ° C. being possible, for example, as the boiling point for a predetermined area of application. The boiling temperature of the fluid 14 can also be set by varying an internal pressure in the heat transport unit 1, which can be, for example, 1 to 10 bar. The heat transport unit 1 can be designed with a length of less than 2 cm or also with a length of more than 1 m, with diameters from less than 1 mm to over 10 mm depending on the application. For a flexible heat transport unit 1 with a diameter of 10 mm, heat transfer with a heat output of 1200 watts can be achieved, specifically at a temperature difference of 10 ° C. between the evaporation area 2 and the condensation area 3. The end pieces, that is to say the plastic sleeves 6, 7 8 of the heat transport unit 1 can be thermally conductively connected to thermocouple units 31 designed as metal blocks, for example in that the end pieces are inserted into bores 51 of these thermocouple units 31. These thermal coupling units 31 can then in turn be connected on the one hand to heat sources - for example a microprocessor 32 - or on the other hand with cooling devices 33 in a heat-conducting manner in order to implement a heat transport system. The arrows drawn in FIG. 8 show, by way of example, the transport direction of the heat transfer via the heat transport units 1.

FIG. 2 shows a modified embodiment of the heat transport unit 1 according to FIG. 1 according to the invention, in which, however, a flow resistance element 17 is additionally provided as an annular rim which projects inwards on the plastic sleeve 6. The ring edge can also be referred to as an annular bead and serves to narrow a cross section for the backflow of the fluid 14 in this transition area between the evaporation area 2 and the line area 4. It is thereby achieved that the evaporated fluid 14 ″ preferably selects the path through the inner tube 10 in the direction of the arrow 15. It is important that the flowing back condensed fluid is not prevented too strongly from the backflow in the direction of the arrow 16 to the evaporation region 2. The same also applies to a similar flow resistance element 18 at the transition area between the line area 4 and the condensation area 3.

The two flow resistance elements 17, 18 also serve as

Centering elements for the inner tube 10, so that it is at least approximately concentrically arranged in the outer tube 9 or to the plastic sleeves 6, 7 in the transition areas. The flow resistance elements 17, 18 can very advantageously also be designed as knobs that lie between them Fix the inner tube 10 in place. Clearances can remain between the individual knobs, through which the back-flowing fluid 14 can flow back from the condensation area 3 to the evaporation area 2 in accordance with the direction of the arrow 16.

The flow resistance elements 17, 18 can also be designed as circumferential ring beads or ring diaphragms, which stand inwards from the outer hose 9 and have a larger inner diameter than an outer diameter of the inner hose 10 or which stand outwards from the inner hose 10 and have a smaller outer diameter than an inner diameter of the Outer hose 9, so that there is an annular gap 19 between the flow elements 17, 18 and the inner hose 10 or the outer hose 9, through which the liquid fluid 14 can flow back from the condensation area 3 to the evaporation area 2.

Another possibility are flow resistance elements 17, 18 in the form of circumferential ring beads or ring diaphragms which have interruptions at peripheral points through which the liquid fluid 14 can flow back from the condensation area 3 to the evaporation area 2 (not shown).

In FIG. 1 and FIG. 2, the heat transport unit 1 is filled approximately halfway with liquid fluid 14 and otherwise with gaseous or vaporous fluid 14 '. The fill level can be selected differently depending on the area of application and the fluid used and changes as a result of the evaporation of part of the fluid 14. Good circulation properties have been achieved at a fill level of 30% to 50% of the volume with liquid fluid 14. Depending on the fluid used and depending on the area of application, other fill levels may be appropriate.

FIG. 3 shows a longitudinal section of the heat transport unit 1 from FIG. 2 in the evaporation area 2. By supplying heat in the direction of the arrow 13 via the plastic sleeve 6 to the fluid 14, the fluid 14 is heated so that an evaporation process takes place. Here bubbles 20 rise in the fluid 14, which is indicated by individual arrows. Since the effective line cross section of the inner tube 10 is larger than the line cross section provided for the backflow in the direction of the arrow 16, the fluid 14 evaporates via the inner tube 10 and thus also passes through the Inner hose 10 to the condensation area 3 (Fig. 1, Fig. 2). Due to their size, large gas bubbles 24 do not enter the annular gap between the outer tube 9 and the inner tube 10 and burst before they get into the inner tube 10. Due to their formation and bursting, the large gas bubbles 24 generate a pulsating pressure in the evaporation area 2, which causes a pumping effect, which also displaces the fluid 14 liquid into the inner tube 10, as a result of which the fluid 14 circulates from the evaporation area 2 into the inner tube 10 Condensation area 3 and through the annular gap 19 between the outer tube 9 and the inner tube 10 back into the evaporation area 2. The fluid 14 is, so to speak, "pumped" in the circuit by the pulsating pressure that the gas bubbles 24 that develop and burst when heat is applied in the evaporation region 2.

FIG. 4 shows an embodiment of a double hose line 8 in which the outer hose 9 has a capillary structure 21 on its inner wall, which extends over the entire length of the outer hose 9. The broken circular line indicates that the capillary structure 21 can extend over the entire circumference on the inner wall. Figure 5 shows the longitudinal section of the arrangement shown in Figure 4.

6 and FIG. 7 show a cross section and a longitudinal section of a double hose line 8 with an inserted wick element 22 extending over the entire length. For example, the wick element 22 here extends only over a partial segment of the space 23 provided for the backflow from the condensation area 3 to the evaporation area 2 In principle, the wick element 22 can also completely fill the intermediate space 23. The wick element 22 and the capillary structure 21 (FIGS. 4, 5) can help to support the backflow of the condensed fluid 14.

FIG. 9 shows a heat transport unit 1 according to the invention with the functionality of a heat pipe, which, as in FIGS. 1 and 2, has an evaporation region 2 and a condensation region 3, which are connected to one another via a line region 4 for the transmission of thermal energy. As in FIGS. 1 and 2, the line area 4 in FIG. 9 is flexible and is formed by a double hose line 8 with an outer hose 9 and an inner hose 10. A diameter of the inner tube 10 is 2/3 as large as a diameter of the outer tube 9. The inner tube 10 has a half the contact resistance for the flow of the fluid 14 with gas bubbles 24 as the outer tube 9 or the annular space 19 between the outer tube 9 and the inner tube 10 for the backflow of the fluid 14, which contains no gas bubbles here.

At or near an end facing the evaporation area 2, the inner tube 10 has a sleeve 25 which projects obliquely outwards and in the direction of the evaporation area 3. In the exemplary embodiment, the sleeve 25 has the shape of a hollow truncated cone and is limp or elastic. The sleeve 25 is axially long enough that it can rest against the inside of the outer hose 9 and block against a flow of the fluid 14 from the evaporation area 2 to the condensation area 3 in the annular gap 19 between the outer hose 9 and the inner hose 10. The flow of the fluid 14 from the condensation area 3 to the evaporation area 2 lifts the cuff 25 off the outer tube 9 and presses it inwards in the direction of the inner tube 10, so that the fluid 14 can flow past the cuff 25 into the evaporation area 2. The cuff 25 forms a non-return valve, which blocks flow in the annular gap 19 between the outer hose 9 and the inner hose 10, which forms the conduit for the flow of the liquid fluid 14 from the condensation area 3 to the evaporation area 2, in the opposite direction. The cuff 25 forming the check valve can also be arranged elsewhere between the evaporation area 2 and the condensation area 3 in the annular gap 19 between the outer hose 9 and the inner hose 10 and it can protrude obliquely inwards from the outer hose 9 (not shown) instead of as shown from Project the inner hose 10 at an angle to the outside.

In the inner tube 10 there is also a flexible or elastic sleeve 26 which projects obliquely inwards and in the direction of the condensation area 3. This sleeve 26 is axially so short that it cannot close the inner tube 10, but only reduces its flow cross-section. The sleeve 26 in the inner tube 10 forms a backflow throttle, which opposes the flow in the intended direction from the evaporation area 2 to the condensation area 3, or only a small flow resistance, whereas it opposes a reverse flow with a high or at least higher resistance. The cuff 25 on the outside Inner hose 10 can generally also be understood as a reflux throttle, which, however, blocks flow against the intended direction.

Designs of the heat transport unit 1 without the two sleeves 25, 26 or with only one of the two sleeves 25, 26 are possible.

In the outer tube 9 there are also in the region of the end of the inner tube 10 facing the evaporation zone 2 a frustoconical hollow cone 27 which is inclined inwards from the outer tube 9 in the direction of the evaporation zone 2, and in the evaporation zone 2 there is an annular, inwardly standing, hollow, round vortex 28, which is arranged closer to the end of the inner tube 10 than at the end of the evaporation region 2. Designs of the heat transport unit 1 without or with only one swirler 27, 28 are possible.

By supplying heat 13, gas bubbles 24 with a larger diameter than the diameter of the inner tube 10 are formed in the evaporation area 2, which must reduce their diameter for entry into the inner tube 10 and thereby lengthen axially. The gas bubbles 24 are too large to enter the annular gap 19 between the outer tube 9 and the inner tube 10. The gas bubbles 24 push liquid fluid 14 in the inner tube 10 in front of them from the evaporation area 2 to the condensation area 3. In addition, the gas bubbles 24 generate pressure waves which, due to the larger cross section and because of the swirlers 27, 28 and from the end of the inner tube 10, obliquely outwards continue the protruding cuff 25 into the inner tube 10 more than into the annular gap 19 between the outer tube 9 and the inner tube 10. The pressure waves also convey the fluid 14 in the inner tube 10 from the evaporation area 2 to the condensation area 3.

With the heat transport unit 1 according to the invention shown in FIG. 9 and described above, a flow of the fluid 14 in the inner tube 10 from the evaporation area 2 to the condensation area 3 and thus a heat transport in this direction is also possible against gravity.

Claims

1. Hermetically sealed heat transport unit (1), which contains a gaseous and liquid fluid (14, 14 ') as a heat carrier, with an evaporation area (2) and with a condensation area (3) and between the evaporation area (2) and the condensation area ( 3) arranged line area (4) via which thermal energy is transported from the evaporation area (2) to the condensation area (3), the line area (4) consisting of two connecting lines and wherein fluid (14 ') evaporated through one of the two connecting lines from the evaporation area (2) arrives at the condensation area (3) and the other of the two connecting lines serves as a return line for condensed fluid (14), characterized in that the heat transport unit (1) is designed as a flexible heat pipe and that a cross-sectional area for a line of the evaporated Fluids (14 ') from the evaporation area (2) to the condensation area (3) v The connecting line provided is larger than a cross-sectional area of the connecting line provided for the return of the condensed fluid (14) from the condensation area (3) to the evaporation area (2).

2. Heat transport unit according to claim 1, characterized in that the cross-sectional area of the connecting line provided for the conduction of the evaporated fluid (14 ') from the evaporation area (2) to the condensation area (3) is at least twice as large as the cross-sectional area of the return line for the condensed fluid (14) from the condensation area (3) to the evaporation area (2) provided connecting line.

3. Heat transport unit according to claim 1 or 2, characterized in that a diameter of the connecting line provided for the conduction of the evaporated fluid (14 ') from the evaporation region (2) to the condensation region (3) is smaller than a diameter of gas bubbles which are present when the Fluids (14) arise in the evaporation area (2).

4. Heat transport unit according to one or more of claims 1 to 3, characterized in that the fluid (14) in the evaporation area (2) is liquid.

5. Heat transport unit according to one or more of the preceding claims, characterized in that an outer connecting line is elastically expandable.

6. Heat transport unit according to one or more of the preceding claims, characterized in that the connecting lines form a flexible double hose line (8) consisting of an outer hose (9) and an inner hose (10) extending in the outer hose (9).

7. Heat transport unit according to one or more of the preceding claims, characterized in that the return line has a capillary structure (21) on its inner wall.

8. Heat transport unit according to one or more of the preceding claims, characterized in that at least one flow resistance element (17) is arranged in the transition region between one of the two connecting lines and the evaporation region (2).

9. Heat transport unit according to one or more of the preceding claims, characterized in that the connecting line through which the evaporated fluid (14 ') from the evaporation area (2) to the condensation area (3) has a reflux throttle (26) which allows a backflow of Fluid from the condensation area (3) to the evaporation area (2) opposes a greater flow resistance than the flow from the evaporation area (2) to the condensation area (3) and / or that for the return of the condensed fluid (14) from the condensation area (3) to the evaporation area ( 2) provided connecting line has a reflux throttle (25) which opposes a flow of fluid from the evaporation area (2) to the condensation area (3) a greater flow resistance than the backflow of fluid from the condensation area (3) to the evaporation area (2).

10. Heat transport unit according to one or more of the preceding claims, characterized in that the evaporation area (2) and the condensation area (3) consist of a material with high thermal conductivity.

11. Heat transport unit according to claim 10, characterized in that the material is a plastic material with additives that increase the thermal conductivity.

12. Heat transport unit (1) according to one or more of the preceding claims, characterized in that the fluid (14, 14 ') has a low boiling temperature, which at a pressure of 0.001 to 100 bar in a range between -20 ° Celsius and + 1000 ° Celsius.

13. Heat transport unit according to one or more of the preceding claims, characterized in that the connecting line provided for the forwarding of the vaporized fluid (14 ’) projects slightly into the space of the evaporation area (2) and deep into the space of the condensation area (3).

14. Heat transport unit according to one or more of the preceding claims, characterized in that a capillary structure (21) is produced on an inner wall of one of the connecting lines in the extrusion process.

15. Heat transport unit according to one or more of the preceding claims, characterized in that the heat transport unit (1) is used for cooling electronic components, in particular microprocessors, in an electrical device.