EP3926285A1 - Wärmerohr, system und verfahren zum schalten und/oder programmieren eines wärmetransports - Google Patents

Wärmerohr, system und verfahren zum schalten und/oder programmieren eines wärmetransports Download PDF

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Publication number
EP3926285A1
EP3926285A1 EP20180665.0A EP20180665A EP3926285A1 EP 3926285 A1 EP3926285 A1 EP 3926285A1 EP 20180665 A EP20180665 A EP 20180665A EP 3926285 A1 EP3926285 A1 EP 3926285A1
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EP
European Patent Office
Prior art keywords
heat
working fluid
heat pipe
area
designed
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
EP20180665.0A
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German (de)
English (en)
French (fr)
Inventor
Martin Kluge
Jürgen Dr. Clade
Christoph Prof. Dr. EBERL
Markus Dr. WINKLER
Erik Dr. Wischerhoff
Kilian Dr. BARTHOLOMÉ
Olaf Dr. SCHÄFER-WELSEN
Murat Dr. TUTUS
Martin Prof. Dr. KRUS
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Fraunhofer Gesellschaft zur Forderung der Angewandten Forschung eV
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Fraunhofer Gesellschaft zur Forderung der Angewandten Forschung eV
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Application filed by Fraunhofer Gesellschaft zur Forderung der Angewandten Forschung eV filed Critical Fraunhofer Gesellschaft zur Forderung der Angewandten Forschung eV
Priority to EP20180665.0A priority Critical patent/EP3926285A1/de
Priority to CN202180047345.0A priority patent/CN115968437A/zh
Priority to PCT/EP2021/066424 priority patent/WO2021255176A1/de
Priority to JP2022577654A priority patent/JP2023531430A/ja
Priority to US18/011,247 priority patent/US20230417492A1/en
Priority to KR1020237002195A priority patent/KR20230037570A/ko
Publication of EP3926285A1 publication Critical patent/EP3926285A1/de
Pending legal-status Critical Current

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
    • F28D15/00—Heat-exchange apparatus with the intermediate heat-transfer medium in closed tubes passing into or through the conduit walls ; Heat-exchange apparatus employing intermediate heat-transfer medium or bodies
    • F28D15/02—Heat-exchange apparatus with the intermediate heat-transfer medium in closed tubes passing into or through the conduit walls ; Heat-exchange apparatus employing intermediate heat-transfer medium or bodies in which the medium condenses and evaporates, e.g. heat pipes
    • F28D15/06—Control arrangements therefor
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
    • F28D15/00—Heat-exchange apparatus with the intermediate heat-transfer medium in closed tubes passing into or through the conduit walls ; Heat-exchange apparatus employing intermediate heat-transfer medium or bodies
    • F28D15/02—Heat-exchange apparatus with the intermediate heat-transfer medium in closed tubes passing into or through the conduit walls ; Heat-exchange apparatus employing intermediate heat-transfer medium or bodies in which the medium condenses and evaporates, e.g. heat pipes
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
    • F28D15/00—Heat-exchange apparatus with the intermediate heat-transfer medium in closed tubes passing into or through the conduit walls ; Heat-exchange apparatus employing intermediate heat-transfer medium or bodies
    • F28D15/02—Heat-exchange apparatus with the intermediate heat-transfer medium in closed tubes passing into or through the conduit walls ; Heat-exchange apparatus employing intermediate heat-transfer medium or bodies in which the medium condenses and evaporates, e.g. heat pipes
    • F28D15/04—Heat-exchange apparatus with the intermediate heat-transfer medium in closed tubes passing into or through the conduit walls ; Heat-exchange apparatus employing intermediate heat-transfer medium or bodies in which the medium condenses and evaporates, e.g. heat pipes with tubes having a capillary structure
    • F28D15/046—Heat-exchange apparatus with the intermediate heat-transfer medium in closed tubes passing into or through the conduit walls ; Heat-exchange apparatus employing intermediate heat-transfer medium or bodies in which the medium condenses and evaporates, e.g. heat pipes with tubes having a capillary structure characterised by the material or the construction of the capillary structure
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
    • F28F13/00—Arrangements for modifying heat-transfer, e.g. increasing, decreasing
    • F28F2013/005—Thermal joints
    • F28F2013/008—Variable conductance materials; Thermal switches
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
    • F28F2245/00—Coatings; Surface treatments
    • F28F2245/02—Coatings; Surface treatments hydrophilic
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
    • F28F2245/00—Coatings; Surface treatments
    • F28F2245/04—Coatings; Surface treatments hydrophobic

Definitions

  • the invention relates to a heat pipe according to the preamble of claim 1, a system with a heat pipe according to claim 12 and a method for switching and / or programming the heat transport in a heat pipe according to the preamble of claim 15.
  • heat pipes also known as heat pipes
  • Heat pipes enable a high heat flux density due to the heat transport via evaporation heat.
  • Heat pipes usually have a hot side, the heat source, and a cold side, the heat sink.
  • a working fluid is provided in the heat pipe, which is evaporated in the area of the heat source and condenses in the area of the heat sink.
  • the heat transport takes place via the transport of the working fluid and the transfer by means of latent heat of condensation and evaporation.
  • Known heat pipes have a preferred direction for the heat flow, that is, they are designed as thermal diodes. This means that the diode conducts heat very well in one direction and very poorly in the opposite direction.
  • thermal diode is for example in Boreyko et al. 2011, Applied Physics Letter 99 (23 ) as well as in the publication US 8716689 B2 described.
  • the use of superhydrophobic coatings in the area of the heat sink and superhydrophilic coatings in the area of the heat source creates a preferred direction of the thermal diode described for the heat: Due to the superhydrophobic coating, the surface in the area of the heat sink repels the working fluid so that it returns to the superhydrophilic area the heat source is transported and can evaporate again there.
  • the invention is therefore based on the object of proposing a heat pipe or a method for heat transport that is more variable and overcomes the limits of the methods and devices known from the prior art.
  • the heat pipe according to the invention comprises at least one working chamber with at least one evaporator area and at least one condenser area.
  • the evaporator area is in operative connection with a heat source and the condenser area is in connection with a heat sink.
  • a working fluid is provided in the working chamber. In a first operating state, heat is transported from the heat source to the heat sink by means of the working fluid.
  • the heat pipe is designed as a switchable and / or programmable thermal diode or heat switch, in which at least one activatable functional material is provided, which is arranged and designed to keep the evaporator area free of the working fluid in a second operating state and / or to prevent the working fluid from evaporating in order to reduce and / or prevent the heat transport and / or to change the preferred thermal conduction direction of the heat transport.
  • the working fluid fills the working chamber and, depending on the pressure and temperature, is both liquid and gaseous.
  • the phrase "to keep the evaporator area free of the working fluid" refers to the working fluid in the liquid phase in direct contact and / or direct interaction with the surface of the evaporator area. It is also within the scope of the invention that working fluid is present in the gaseous phase in the evaporator area, since the working fluid in the gaseous phase fills the entire volume of the working chamber of a heat pipe.
  • the invention is based on the applicant's knowledge that the heat transport can be controlled and even reversed by means of a corresponding design of the conditions in the working chamber.
  • the heat pipe according to the invention thus differs in essential aspects from previously known heat pipes:
  • An activatable functional material is provided in the heat pipe, which can change from a first state (first operating state of the heat pipe) to a second state (second operating state of the heat pipe).
  • first state the functional material that can be activated enables heat to be transported in the preferred thermal conduction direction of the first operating state or has no influence on the function of the heat pipe.
  • second state the activatable functional material keeps the evaporator area free of the working fluid or prevents the working fluid from evaporating.
  • the activatable functional material is designed in such a way that in the second operating state the preferred thermal conduction direction is changed by the activatable functional material.
  • the heat pipe is designed as a switchable thermal diode or heat switch, in which the at least one activatable functional material is designed, in an outer one Field to at least partially change its properties.
  • Possible properties of the activatable functional material are surface wetting properties, swelling capacity, fluid-binding properties and volume.
  • the heat pipe is designed as a programmable thermal diode or heat switch, in which the at least one activatable functional material is designed to at least partially change its properties depending on conditions within the working chamber.
  • Possible properties of the activatable functional material are surface wetting properties, swelling capacity, fluid-binding properties and volume.
  • the functional material that can be activated is thus preferably switchable or programmable by external or internal influences.
  • switchable means that the operating state can be changed by actively applying an external field.
  • programmable means that the heat pipe changes its state automatically due to internal factors inherent in the material when ambient conditions, in particular the conditions in the working chamber, change.
  • the heat pipe is designed as a programmable thermal diode or heat switch in which the at least one activatable functional material is designed, depending on conditions within the working chamber, in particular temperature, pH value of the working fluid and / or ionic strength of the working fluid to change its properties. So there are advantageously no external fields necessary, but the control of the heat transport in the heat pipe can take place solely via the working fluid or direct properties of the heat pipe.
  • the working chamber is preferably designed as a closed volume, in particular such that a heat transport by means of convection of the evaporated fluid and a return transport of the condensed fluid from the Condenser area takes place in the evaporator area.
  • the closed volume of the working chamber is designed as a pressure-tight system.
  • essentially all foreign gases with the exception of the working fluid have been removed from the pressure-tight system.
  • Various designs are possible for this, which differ in the return transport of the working fluid.
  • the design as a heat pipe or as a 2-phase thermosyphon is known here.
  • the functional material that can be activated is preferably provided within the working chamber. It is also possible that the functional material that can be activated is provided as part of the working chamber, for example of the floor and ceiling of the working chamber.
  • the heat pipe is designed with a fluid circuit for the working fluid.
  • the fluid circuit preferably comprises a fluid return for a return transport of the condensed working fluid from the condenser area to the evaporator area. In this way, the working fluid can be guided back into the evaporator area in a targeted and metered manner, thus preventing the evaporator area from drying out.
  • the enclosed volume has a fluid-phobic coating in the evaporator area and / or a fluid-phobic coating in the condenser area. It is also within the scope of the invention that the closed volume, that is to say the working chamber, has an additional structure both in the evaporator area and / or in the condenser area. In this way, for example, the wetting properties of the surfaces can be optimized.
  • the at least one activatable functional material is preferably designed in the form of a switchable coating of the evaporator area and / or the condenser area of the working chamber, in that at least the surface properties of the coating of the evaporator area can be changed from fluid-philic to fluid-phobic.
  • both the coating of the evaporator area and the condenser area are designed in such a way that the surface property of the coating of the evaporator area is fluid-philic fluid-phobic is changeable, while the surface property of the coating of the capacitor area can be changed from fluid-phobic to fluid-phobic.
  • the heat pipe is designed as a switchable thermal diode: by applying an external field, the heat pipe can be changed from the first operating state to the second operating state.
  • the working fluid that has collected on the fluid-philic coating of the evaporator area evaporates and enables heat to be transported from the evaporator area to the condenser area.
  • the working fluid condenses on the fluid-phobic coating of the condenser area. Because of the fluid-phobic surface property in the condenser area, drops form in the working fluid. In the case of a highly fluid-phobic configuration of the surface, the working fluid "jumps" back into the evaporator area.
  • a fluid return of the droplets via capillary forces can also be provided, for example in the form of a hydrophilic wick structure, as is known from the prior art for heat pipes. In this state the thermal diode is thermally conductive.
  • the hot side i.e. the evaporator area
  • the hot side now has hydrophobic properties at the heat source.
  • Not enough working fluid collects on this coating and the working fluid that collects there evaporates quickly and condenses on the fluid-philic coating of the condenser area.
  • the working fluid remains there and is not transported back into the evaporator area, since the above-mentioned return mechanisms do not work.
  • the hot side of the working chamber dries out and there is no heat transfer via the working fluid.
  • the switchable coating as ORMOCER ® and / or with ORMOCER ® is formed.
  • ORMOCER ® e are inorganic-organic hybrid polymers that can advantageously influence the surface properties of many substrates, cf. B. Sanchez et al., Chem. Soc. Rev. 40, 2011, 696-753 .
  • ORMOCER ® e can also be designed as switchable coatings from hydrophilic to hydrophobic and back using mechanisms known from the specialist literature, see B. Xin, J. Hao, Chem. Soc. Rev. 39, 2010, 769-782 .
  • ORMOCER ® e according to the invention therefore contain z. B.
  • the ORMOCER ® coatings have a micro-, meso- or nano-structuring that reinforces their fluid-philic / fluid-phobic properties by utilizing the capillary or lotus effect.
  • the functional material that can be activated is designed in such a way that the evaporator area and condenser area exchange properties in the second operating state.
  • the second operating state is therefore not a blocking state, but rather enables heat to be transported in the opposite direction to the first operating state.
  • the working fluid in the second operating state, can evaporate in the original condenser area, which now acts as the evaporator area, and absorb heat from a heat source and transport it to the original evaporator area, which now acts as the condenser area.
  • the working fluid condenses in the new condenser area and transfers the heat to a heat sink. This reverses the preferred thermal conduction direction of the thermal diode.
  • the activatable functional material is formed both in the evaporator region than in the capacitor area as ORMOCER ® coating.
  • the coatings are selected so that the application of an external field, preferably an electric field or a radiation field, ie (UV) light radiation, swaps the surface wetting properties of the evaporator area and the condenser area.
  • the functional end groups of an ionic group consists of a "spacer", ie a linear alkyl chain with 2-20 carbon atoms, preferably 3-12 carbon atoms, are covalently bound to the ORMOCER ® network.
  • the electrical voltage to be applied to the thermal diode is preferably ⁇ 50 V, particularly preferably ⁇ 5 V.
  • the at least one functional material that can be activated is designed in the form of a reservoir for the working fluid, in particular in the form of a liquid reservoir.
  • the reservoir controls the uptake or release of the working fluid required for heat transport. This means that the available amount of the working fluid can be made variable.
  • the working fluid In the first operating state of the heat pipe, the working fluid is available for heat conduction. The heat pipe conducts heat.
  • the second operating state, the blocking state the working fluid is bound in the reservoir, in particular in the form of a liquid reservoir. In this bound form, the working fluid is no longer available for heat transport. The heat pipe no longer conducts heat.
  • the phrase "the heat pipe no longer conducts heat” means the blocking state of the diode. This means that the heat transport is considerably reduced compared to the other switching state. Nevertheless, a small heat flow can take place, for example via the thermal conduction of components.
  • the reservoir for the working fluid is preferably designed as a gel, in particular as a polymer gel, as an adsorbent or as a mesoscopically structured surface.
  • the reservoir is particularly preferably designed as a chemically crosslinked polymer gel.
  • the crosslinked polymer gel is designed in such a way that it swells up due to the working fluid and then exhibits a volume phase transition, preferably between a swollen and a collapsed state of the hydrogel.
  • the reservoir is preferably designed as a water-binding hydrogel.
  • the polymer gel has a water-binding and a non-water-binding state.
  • the transition from the first operating state to the blocking state of the heat pipe, that is to say from a non-fluid-binding state of the polymer gel to the fluid-binding state of the polymer gel, is preferably induced by a temperature transition.
  • the polymer gel can be designed as a polymer gel with a volume phase transition of the UCST type (Upper Critical Solution Temperature) or of the LCST type (Lower Critical Solution Temperature).
  • the crosslinked polymer gel is only swollen when the working fluid exceeds the critical temperature (limit temperature).
  • the working fluid is displaced from the crosslinked polymer gel when the critical temperature (limit temperature) is exceeded.
  • the heat pipe blocks in the event of a UCST transition above the critical temperature.
  • the heat pipe blocks below the critical temperature.
  • the limit temperature can thus be used to define a switching temperature for the transition from the first operating state to the blocking state of the heat pipe.
  • Known polymers that have a UCST volume phase transition are, for example, in Macromol. Rapid Commun. 33, 1898-1920, 2012 described.
  • Known polymers that exhibit an LCST volume phase transition are, for example, in Adv. Polym. Sci. 242, 29-89, 2011 described.
  • the named polymer gels interact with water and are therefore particularly suitable for a heat pipe in which water is used as the working fluid. It
  • organic fluids such as mineral oils, for example J. Polym. Sci. A46, 5724 - 5733, 2008 .
  • a fluid other than water can also be used as the working fluid.
  • the reservoir is designed as an adsorbent.
  • An adsorbent binds fluid.
  • the amount of fluid bound in the adsorbent is also referred to as the load. With increasing temperature (and the associated increasing vapor pressure of the bound fluid) the loading of an adsorbent decreases and the fluid is released again.
  • the adsorbent preferably has a limit temperature so that when this limit temperature or a specific vapor pressure of the fluid is exceeded, the fluid is released again quite abruptly by the adsorbent.
  • a switching temperature for the transition from the blocking state to the first operating state of the heat pipe can thus be defined.
  • a material example for an adsorbent with a defined limit temperature or the associated vapor pressure of the fluid is the adsorbent AQSOA TM -Z05 from Mitsubishi TM .
  • the properties of the liquid reservoir are not influenced by temperature, but by another physical or chemical stimulus. Examples of this are UV light or microwave radiation as well as pH value, ionic strength or the presence of certain organic molecules. Examples are in Applied Chem. Int. Ed. 55, 6641 - 6644, 2015 described.
  • the switching of the thermal diode is therefore possible due to a wide variety of factors and can be adapted accordingly to the area of application and the ambient conditions.
  • the object according to the invention is also achieved by a system with a heat pipe with the properties according to the invention described above and means for applying a field in order to change the properties of the functional material that can be activated.
  • Field generators for an E field, a B field, a stress-strain field, for generating light, in particular UV light, for generating heat and / or for generating cold are preferably provided as the means for applying the field. Only one of the named field generators or a combination of several of the named field generators can be provided. Examples of this are a capacitor, a coil, an eccentric, a (UV) light source or a heating and cooling device. As a result, the control options can be individually adapted to the working fluid used and to the functional material that can be activated.
  • the system according to the invention also has the advantages and properties of the heat pipe according to the invention and / or a preferred embodiment thereof described above.
  • the system is preferably designed to be flexible with regard to the hot side and cold side.
  • the heat pipe is designed as a heat pipe with a reversible preferred heat conduction direction, means are preferably provided that the evaporator area and condenser area are assigned their function through contact with a hot side or, accordingly, a cold side. Good thermal contact is preferably provided between the evaporator area and the condenser area and the hot side or cold side. There is good thermal contact between the heat sink and the heat source and the heat pipe.
  • the system is designed with a heat pipe with a combination of two functional materials, one of the two functional materials being designed as a liquid reservoir described above, in particular in the form of a polymer gel.
  • the other functional material is preferably formed as a fluidphoben in its fluid hydrophilic / properties changeable ORMOCER ®, preferably under the influence of light, in particular UV light.
  • the heat pipe is operated as a thermal diode or heat switch in that the thermal conductivity is changed by applying an external field and / or depending on conditions within the working chamber.
  • the method according to the invention is preferably designed to be carried out by means of the heat pipe according to the invention and / or a preferred embodiment of the heat pipe according to the invention.
  • the heat pipe according to the invention is preferably designed to carry out the method according to the invention and / or a preferred embodiment of the method according to the invention.
  • the method according to the invention also shows the advantages and features of the heat pipe according to the invention and / or the system according to the invention described above.
  • the thermal conductivity of the heat pipe is changed in that the evaporator area is kept free of the working fluid and / or the working fluid is prevented from evaporating.
  • heat in a first operating state, heat is transported in the heat pipe from a hot side (heat source) arranged on the evaporator area to a cold side (heat sink) arranged on the condenser area.
  • a hot side heat source
  • a cold side heat sink
  • the heat pipe is transferred to a second operating state.
  • an E field, a B field, a stress-strain field is preferably generated or the activatable functional material is exposed to light, in particular UV light, with heat and / or cold.
  • no or at least insufficient working fluid is available in the evaporator area.
  • the evaporator area dries out and the heat pipe no longer conducts heat in the direction of the preferred thermal conduction direction of the first operating state.
  • the working fluid can change from the first operating state to the second operating state as a function of conditions within the working chamber.
  • Parameters that can initiate a change from the first operating state to the second operating state are temperature, pH value of the working fluid and / or ionic strength of the working fluid. This has the advantage that the heat pipe can be "programmed" to change the operating state under certain conditions without any external influence being necessary.
  • the working fluid is preferably displaced from the evaporator area of the working chamber by means of a switchable surface coating, as already described above.
  • the working fluid can be bound by means of an activatable functional material.
  • the at least one activatable functional material is preferably designed in the form of a reservoir for the working fluid, in particular in the form of a liquid reservoir.
  • the reservoir controls the uptake or release of the working fluid necessary for the heat transport. This means that the available amount of the working fluid can be changed.
  • the working fluid In the first operating state of the heat pipe, the working fluid is available for heat conduction. The heat pipe conducts heat.
  • the second operating state the blocking state, the working fluid is bound in the reservoir, in particular in the form of a liquid reservoir. In this bound form, the working fluid is no longer available for heat transport. The heat pipe no longer conducts heat.
  • the preferred thermal conduction direction of the thermal diode is reversed by exchanging the surface properties of the evaporator area and condenser area by applying an external field and / or depending on conditions within the working chamber.
  • the working fluid in a second operating state, can evaporate in the original condenser area, which now acts as the evaporator area, and absorb heat from a heat source and transport it to the original evaporator area, which now acts as the condenser area.
  • the working fluid condenses in the new condenser area and transfers the heat to a heat sink.
  • the preferred thermal conduction direction is reversed compared to operating state 1.
  • the heat pipe according to the invention, the system according to the invention and the method according to the invention are particularly suitable for being able to effectively switch heat flows on and off or to control or regulate them.
  • Heat switches or thermal diodes based on heat pipes are particularly suitable because they can achieve high switching factors and, due to the high heat transport in the conductive state, only have a very low thermal resistance. In addition, they can be implemented as very compact designs and are therefore easy to integrate.
  • the heat pipes have a simple structure, consist of a few individual parts and do not have to contain any moving parts.
  • Figure 1 shows a schematic representation of a thermal diode with an activatable functional material in the form of a switchable coating in the Evaporator area and the condenser area with the partial images a) in the conductive state and b) in the blocked state.
  • the heat pipe 1 has a working chamber 2 with at least one evaporator area 3 and at least one condenser area 4.
  • a working fluid 5 is provided in the working chamber 2 in the working chamber 2, a working fluid 5 is provided in the working chamber 2, a working fluid 5 is provided in the working chamber 2, a working fluid 5 is provided in the working chamber 2, a working fluid 5 is provided.
  • the working chamber 2 is designed as a closed, pressure-tight volume which is designed in such a way that heat is transported by means of convection of the evaporated working fluid 5 and the condensed working fluid 5 is transported back.
  • the working fluid 5 is water.
  • the evaporator area 3 and the condenser area 4 are formed with a coating 6 made of functional material that can be activated. Both the coating 6 of the evaporator area 3 and the condenser area 4 are designed in such a way that the surface property of the coating 6a of the evaporator area 3 can be changed from hydrophilic to hydrophobic and back again, while the surface property of the coating 6b of the condenser area 4 can be changed from hydrophobic to hydrophilic and back again is changeable.
  • the coatings 6 are designed in such a way that the evaporator area 3 and condenser area 4 have exactly the opposite surface wetting properties.
  • the coating 6 is formed of activatable function as a switchable material coating 6 of ORMOCER ® and / or with ORMOCER ®.
  • ORMOCERE ® are inorganic-organic hybrid polymers that can advantageously influence the surface properties of many substrates. ORMOCERE ® can hydrophobic from hydrophilic and are formed back by utilizing known from the literature mechanisms as switchable coatings 6, see B. Xin, J. Hao, Chem. Soc. Rev. 39, 2010, 769-782 .
  • the coatings are formed in the evaporator 6a and 6b region 3 in the condenser section 4 with an electrically switchable ORMOCER ®, as described above.
  • the coatings consist of an ORMOCER ® with functional end groups in the form of methylimidazoliumdodecylsilyl groups.
  • the substrate in the evaporator area is designed to be electrically charged with the same name. This leads to a hydrophilic property of the surface 6a in the evaporator area 3.
  • an electrically oppositely charged substrate is provided in the condenser area 4. As a result, however, the ionic groups are attracted, so that the non-polar dodecyl chains protrude into the interior of the thermal diode, which leads to a hydrophobic property of the surface 6b in the capacitor area.
  • the heat pipe 1 is thus designed as a switchable thermal diode: In a first operating state, heat is transported from the heat source to the heat sink by means of evaporation of the working fluid 5, in that heat is transported with the gaseous working fluid 5 from the evaporator area 3 to the condenser area 4.
  • the evaporator area 3 is heated by the heat source and the working fluid 5, which has collected on the hydrophilic coating 6a of the evaporator area 3, evaporates and enables heat to be transported from the evaporator area 3 to the condenser area 4.
  • the working fluid 5 condenses on the hydrophobic coating 6b of the capacitor area 4 and the heat is dissipated to a heat sink. Due to the hydrophobic surface property in the condenser area 4, drops form in the working fluid 5. Due to the highly hydrophobic configuration of the surface, the working fluid 5 “jumps” back into the evaporator area 3.
  • the heat pipe 1 can be switched from the first thermally conductive operating state to the second non-thermally conductive operating state.
  • the application of the external field changes the surface properties of the coating 6 in the evaporator area 3 and in the condenser area 4.
  • the evaporator area 3 at the heat source now has hydrophobic properties. Not enough working fluid 5 collects on the coating 6a of the evaporator area 3 and the working fluid 5 that collects there evaporates quickly and condenses on the hydrophilic coating 6b of the condenser area 4.
  • the working fluid 5 remains there and is not transported back into the evaporator area 3, since the working fluid 5 is not repelled by the now hydrophilic surface.
  • the hot side of the working chamber 2 dries out and there is no heat transport via the working fluid 5.
  • the thermal diode blocks are not necessary to transport the working fluid 5.
  • Figure 2 shows a schematic representation of a thermal switch with an activatable functional material in the form of a liquid reservoir with the partial images a) in the conductive state and b) in the blocked state.
  • the at least one activatable functional material is designed in the form of a reservoir for the working fluid 5, namely in the form of a water-binding hydrogel 7.
  • the water-binding hydrogel 7 is designed as follows: For example, hydrogels with a volume phase transition of the LCST type can be produced by radical polymerization using the following monomers.
  • compositions mentioned are not to be understood as exclusive: Composition Monomer 1 Mole% Monomer 2 Mole% Crosslinker Mole% 1 50-80 0 - 30 2 - 20 2 50-85 2 - 30 2 - 20 3 50-85 2 - 30 2 - 20 4th 30-80 10 - 45 2 - 25 5 30-80 10 - 45 2 - 25 6th 30-80 10 - 45 2 - 25 7th 80-98 - 2 - 20 8th 20 - 80 10 - 50 2-20 9 30-90 10 - 40 2 - 20 9 20 - 80 10 - 50 2 - 20
  • hydrogels with a volume phase transition of the UCST type can be prepared by radical polymerization using the following monomers.
  • the compositions mentioned are not to be understood as exclusive: Composition Monomer 1 Mole% Monomer 2 Mole% Crosslinker Mole% 1 80-98 - 2 - 20 2 80-98 - 2 - 20 3 60-90 10-30 2 - 20 4th 60-90 10-30 2 - 20
  • hydrogels that have a volume phase transition.
  • partially hydrolyzed poly (vinyl acetate) can be crosslinked with 1,4-butanediol diglycidyl ether, poly (ethylene glycol) diglycidyl ether or other di- or multifunctional epoxides.
  • the available amount of the working fluid 5 is made variable by the water-binding hydrogel 7.
  • the water-binding hydrogel 7 has a water-binding and a significantly less water-binding state.
  • the transition from the first operating state to the blocking state of the heat pipe 1, i.e. from a significantly less water-binding state of the hydrogel 7 to the water-binding state of the hydrogel 7, is induced by a temperature transition, in the present case in a temperature range from room temperature to approx. 150 ° C . This heating takes place by heating the hot side on the evaporator side, i. H. without an outside field.
  • the working fluid 5 In the first operating state of the heat pipe 1, the working fluid 5 is available for heat conduction. The heat pipe 1 conducts heat. In the second operating state, the blocking state, the working fluid 5 is bound in the water-binding hydrogel 7. The working fluid 5 is not in this bound form more available for heat transport. The heat pipe 1 no longer conducts heat.

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  • Engineering & Computer Science (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Sustainable Development (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Cooling Or The Like Of Semiconductors Or Solid State Devices (AREA)
  • Cooling Or The Like Of Electrical Apparatus (AREA)
EP20180665.0A 2020-06-18 2020-06-18 Wärmerohr, system und verfahren zum schalten und/oder programmieren eines wärmetransports Pending EP3926285A1 (de)

Priority Applications (6)

Application Number Priority Date Filing Date Title
EP20180665.0A EP3926285A1 (de) 2020-06-18 2020-06-18 Wärmerohr, system und verfahren zum schalten und/oder programmieren eines wärmetransports
CN202180047345.0A CN115968437A (zh) 2020-06-18 2021-06-17 热管、系统和用于对传热进行切换和/或编程的方法
PCT/EP2021/066424 WO2021255176A1 (de) 2020-06-18 2021-06-17 Wärmerohr, system und verfahren zum schalten und/oder programmieren eines wärmetransports
JP2022577654A JP2023531430A (ja) 2020-06-18 2021-06-17 ヒートパイプ、熱輸送を切り換えるおよび／またはプログラミングするためのシステムおよび方法
US18/011,247 US20230417492A1 (en) 2020-06-18 2021-06-17 Heat pipe, system and method for switching and/or programming a transport of heat
KR1020237002195A KR20230037570A (ko) 2020-06-18 2021-06-17 히트 파이프, 시스템, 및 열 전달을 스위칭 및/또는 프로그래밍하는 방법

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DE102022210523A1 (de) 2022-10-05 2024-04-11 Vitesco Technologies GmbH Elektrisches Antriebssystem

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102022210523A1 (de) 2022-10-05 2024-04-11 Vitesco Technologies GmbH Elektrisches Antriebssystem

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US20230417492A1 (en) 2023-12-28
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WO2021255176A1 (de) 2021-12-23
KR20230037570A (ko) 2023-03-16

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