DE102009030356A1 - Two-phases-thermosiphon for use as heat exchanger e.g. vacuum tube collector, has covering shells connected one below other so that transmission of latent warmth to surface of heat transfer pipe takes place by working medium - Google Patents

Abstract

The thermosiphon (1) has a pressure-rigid and evacuable container formed as a sandwich element (2) from two covering shells (20, 21) e.g. pins or bolts. The shells are held at a distance by a spacer (22) and vacuum-tightly connected one below the other at edges such that continuous transmission of latent warmth to an outer contact surface of a heat transfer pipe (25) takes place by a gaseous working medium (11) via a bearing surface (12). The working medium flows through the pipe that is formed as a condenser (13). The pipe is centrally arranged in an operating area (10) above a sump (110).

Description

The The invention relates to a two-phase thermosiphon as a heat exchanger with a work surface for absorption and transfer of heat on a heat transfer fluid. The heat exchanger is in a first application as a heat sink, especially as an air conditioning system for the discharge of unwanted, excess Heat from a room provided. The second application for a heat exchanger according to the invention relates to solar thermal collectors as flat plate collectors or vacuum tube collectors, which are rigid or movable towards the sun and in one heat-insulated housing to be installed, the at least on the side facing the sun a glassy Has wrapping element.

State of the art

Heat conduction, Convection and radiation are the three known principles of action for transferring heat from a heat source on a relative to the source cooler heat sink. In collector technology, all three possibilities used the heat transfer to solar won Transfer heat to a heat transfer medium. Copper as a good conductor of heat has been indispensable so far Material. An alternative way of heat absorption and transfer represents a heat pipe, a so-called "heat pipe". Here one uses the heat of vaporization of a substance for the direct and indirect heat transfer too a user application. For a solar thermal collector in shape A heat pipe is the solar radiation from an absorber collected and as completely as possible in heat transformed. By the physical principle of heat conduction is the heat collected by the absorber in an evacuated and partially filled with a liquid working medium Work space transferred to a working medium, the case of heat at least partially evaporated. The steam flows from the bottom End of the heat pipe, the so-called swamp, in the direction of one Condenser, the so-called heat sink. Under a two-phase thermosyphone one understands a gravity-driven heat pipe, with the one condensed on a heat sink working medium independently flows back into the evaporator and is in the liquid Condition in the so-called swamp at the lower end of the heat pipe collects. In this way, a steady heat transfer between the workspace and the condenser, so with a high Heat flow density large amounts of heat to be transported can. Since this without additional aids, such as B. a circulating pump, are heat pipes particularly economical and characterized by a minimal Maintenance and low operating costs. This elegant Principle of heat transfer with a vertical or inclined arranged two-phase thermosyphone has been prevalent so far used in a linear training as a tube. Known heatpipes can only be perpendicular or up to a limit tilt angle be installed by 25 degrees from the horizontal. Conventional heat exchangers and absorber surfaces have a hydraulic structure that is one of a heat transfer fluid flowed through pipe network with heat-conducting surfaces connects and z. B. formed as a serpentine or Harfenabsorber is.

In the DE 20 2008 007 647 is a heat pipe, a so-called. "Heatpipe" described in particular in the application of collectors. In this by a surrounding and evacuated glass tube from heat loss protected heat pipe with a cylindrical cross-section, the absorber surface of a copper sheet, which is thermally conductively connected to an evacuated copper pipe formed. The heat sink is located outside the area protected from heat loss by a surrounding, evacuated glass tube and is connected to this neck, which causes heat loss. Such a heat pipe is suitable for a vertical or inclined (critical angle 25 degrees) arrangement. The diameter of the surrounding glass tube limits the dimensions of the absorber surface to a narrow strip. Another disadvantage is the extensive use of the relatively expensive material copper.

In the DE 10 2006 000 668 B4 an adjustable solar collector in the form of a lamellar register is presented, in each of which a lamella is designed as a heat pipe for the transmission of the heat obtained from the solar radiation to a heat transfer fluid. The heat pipe is a tube with an absorber surface in connection, which forms the lamella shape. The axis of rotation of the slats is arranged concentrically and coaxially to the heat pipe, so that the slats can only be arranged vertically or inclined.

In the DE 20 2007 007 568 a flat heat pipe is described which consists of a bottom plate in the form of a trough and a top plate spaced therefrom, a heat sink and a capillary structure connecting the trough and the top plate. The task of this flat, horizontally arranged heat pipe is to dissipate heat through a heat sink to the surrounding air.

In the DE 103 08 993 A1 a sunlight collector with heat pipe heat exchanger is beschrie ben, in which a corrugated iron absorber and a closing plate form a two-phase thermosyphon effective two-dimensional. The corrugated metal sheet and the closing plate here have individual chambers which are separate from one another and are interconnected at their upper end by a heat carrier tube which laterally crosses the chambers. The structured in the area of the sump into individual, mutually partitioned chambers working space hinders a uniform heat transfer to the heat transfer tube due to an adjusting in operation, non-uniform liquid distribution in the chambers. By a relation to the working space laterally offset arrangement of the heat transfer tube at the upper end of the heat exchanger can not be guaranteed that the outer surface of the heat transfer tube is uniformly flows around the working fluid.

task

It The object of the invention is a large-scale Find heat exchanger, avoiding the disadvantages of the prior art in a vertical or inclined arrangement on the principle of a two-phase thermosyphon on heat input via a work surface in a continuous cycle latent heat on a in a heat transfer tube Guided heat transfer fluid transfers and as a stiff sandwich element a negative pressure of less than 5 Pascals withstand dimensional stability and simple and inexpensive, and save material is to produce. It is especially task the invention, the flow of the working medium in one according to thermodynamic aspects designed working space opposite to improve the state of the art and arrangements for a uniform heat transfer of the working medium on the heat transfer tube inside of the workroom.

These Tasks are solved with the features mentioned in claim 1. Advantageous training opportunities and characteristics The invention will become apparent from the dependent claims.

Of the Working space of an inventive, large-scale Heat exchanger has at its lower end a contiguous Swamp for an even distribution of the working medium. In the case of linear with the cover shells a sandwich element connected spacers to each other Forming chambers, is in this way in the operating state of the heat exchanger each chamber evenly supplied with steam. The Both cover shells of a sandwich element act as Wärmeleitflächen, the the steam targeted to a centrally above the sump Conduct heat transfer tube. The condensation chamber is designed so that the steam targeted to the heat transfer tube is led around. In a heat exchanger with one-sided heat input over the work surface, such as B. in a flat plate, is provided, the working space in a heat source facing the flow chamber, in the the working medium rises in the gas phase and in a rearward Return chamber, in which the condensed working medium under the influence of gravity flows back into the swamp, to divide. The subdivision with a flow guide The working space can also be punctiform for a sandwich element arranged spacers are provided.

A Coating of the working space facing surfaces the cover shells with a nanostructure causes that accordingly the lotus effect pours off the working medium on the surfaces, which supports the cycle of heat absorption and release becomes.

For the optimal effectiveness of a solar thermal collector is the selective coating of the work surface. It can be made in a black chromium chemical process (absorption degree approx. 95%, emissivity approx. 12%) or black nickel (absorption degree about 97%, emissivity about 10-20%) or in a physical Titanium oxynitride process (degree of absorption approx. 95%, emissivity about 5%) by vapor deposition or sputtering on the work surface be applied.

Of the Danger of overheating a solar thermal collector can through a controlled heat dissipation over the flow of heat transfer fluid be counteracted. Another method is a precise dosage the working medium, with a lean design, d. H. With little liquid, a limitation of the operating temperature can be achieved. The spacers between the two cover shells can as

Ribs or arranged as a folded or undulating structure line. But for the production of a contiguous workspace, it is also possible to provide punctiform spacers. However, the spacers can also be formed directly on the cover shells and as linear spacers formed from deep-drawn beads or punctiform spacers made of deep-drawn or drop-forged knobs. A granulate of pressure-stiff bodies or a Pressure-resistant plate made of a metal mesh, which are each loosely connected to the cover shells, may also be provided as a spacer. In accordance with the spacers arranged in a point or line shape, concave or convexly curved surfaces can structure the cover shells and give a sandwich element the necessary dimensional stability to accommodate the changing operating pressures of a two-phase thermosyphone.

One Solar thermal collector requires a heat-insulating Housing to heat loss to the atmosphere keep as low as possible. At least on the sun facing side, this housing has a transparent Enveloping element, that of a glass pane or a vacuum insulating glass pane is formed.

One translucent flat plate collector has more than one another foreclosed working spaces attached to a heat pipe are lined up, with the cover shells between the work spaces Have breakthroughs for daylight. In a particularly advantageous embodiment of a Flat collector is the collector housing as a whole glass construction formed, wherein the acted upon by a vacuum working space is arranged between two vacuum insulating glass panes.

In Slat shape can be a flat plate collector as an element to the sun Alignable lamella register next to the collector function also assume a sun protection function in the area of a facade construction. In a collector blade according to the invention is the pivot axis horizontal, coaxial and concentric with the heat transfer tube arranged, wherein the two-phase thermosyphone perpendicular to a horizontal pivot axis works and for its effectiveness has a critical angle of 25 degrees with respect to the horizontal, so a slat with sun protection function a pivoting range of about 65 degrees.

at a tube collector is the transparent envelope element from a glass tube made of anti-reflective soda-lime glass or plastic.

in the Trap of a vacuum tube collector is a two-sided Silica-steamed soda-lime glass or borosilicate glass pipe intended. The integration of a planar Working two-phase thermosiphons in a glass tube allows the Installation of horizontally or vertically arranged tube collectors especially in the area of a building envelope construction.

copper As a good heat conducting material can be cheaper Metals, such as As stainless steel, to be replaced. This also applies to the cover shells and the linear spacers a sandwich element, possibly with minimal wall thicknesses can be trained.

Of the Working space can be only a few centimeters, but also several meters be high. Particularly advantageous is the complete integration of the heat transfer tube in a sandwich element, whereby elaborate, required outside the work space insulation measures for the heat transfer tube to a minimum are limited.

One inventive heat sink absorbs z. B. excess and unwanted Heat from the room air of a lounge and transmits they for discharging from the room to a heat transfer fluid, whereby a cooling of the room air is effected. A heat sink but can also serve the heat recovery, by cooling hot exhaust gases and z. B. in one Fireplace is installed. The recovered heat is from the heat transfer fluid a Applied utility.

One in parallel chambers partitioned sandwich element can in a Extrusion processes are made of aluminum with a Height of z. B. 1-6 cm are produced, wherein the absorbent work surface by pressed grooves or webs can be extended. Steel sandwich panels in a laser welding process as a large format Made of boards. Curved sandwich panels can be used with each other be added to hollow profiles. In the preferred embodiment is a sandwich element made of thin-walled stainless steel Ultrasonic or laser welding made.

embodiments

The with reference to accompanying figures below embodiments shown each show a two-phase thermosyphone as a large area Heat exchangers in different concrete applications.

It shows:

1 a two-phase thermosiphon as a heat sink in the schematic isometric processing

2 a two-phase thermosiphon as solar thermal flat collector with a surrounding collector housing in the schematic isometric development

3 a two-phase thermosiphon as a flat collector in the form of a movable sunblind in the schematic isometric processing

4 a two-phase thermosiphon as a flat collector in the form of an all-glass construction in the schematic isometric section representation

5 a two-phase thermosiphon as a tube collector in the form of a variable about the horizontal axis x vacuum tube collector in the perspective development

6 a two-phase thermosiphon in the form of a fixed, horizontally arranged vacuum tube collector in the perspective development

7 a two-phase thermosiphon in the form of a vertically arranged tube collector in the schematic isometric section representation

1 shows a large-area heat exchanger 3 as a heat sink 30 , In the workroom 10 a two-phase thermosyphone 1 , there is a working medium 11 , which is in the idle state of the heat sink 30 in the liquid phase in a sump 110 at the bottom of the workroom 10 collects. For heat absorption via one of the cover shells 20 . 21 begins the working medium, z. As water or alcohol or a mixture of both liquids, to vaporize and in the gas phase 111 ascend and the heat transfer tube 25 to condense. By means of a heat transfer fluid 26 In this way, unwanted and excess heat is removed from a room in a continuous process. In order to reduce the boiling point of the alcohol, which is below 78 ° C under atmospheric conditions, to below 25 ° C, a vacuum of approximately 5 Pascal is required in the working space. To ensure this negative pressure over time, a pressure vessel is made of a sandwich element 2 proposed, whose cover shells 20 . 21 by means of a profile sheet 221 kept at a distance and interconnected. The workroom 10 has at the upper end an extension for receiving the heat carrier tube 25 on. transverse ribs 251 and longitudinal ribs 250 within the heat transfer tube cause a good heat transfer latent heat on the condensing working fluid 11 on the heat transfer fluid 26 , In an advantageous arrangement of the heat sink 30 is provided, only one side of the sandwich element 2 with the room air, while the rear side is integrated into a relatively cooler wall structure. This ensures that the working medium 11 in the gas phase 111 in the of the profile sheet 221 formed flow chambers 100 rises and after condensation on the heat transfer tube 25 in the return chambers 101 in the swamp 110 flowing back. In order to allow the best possible heat conduction and for a permanent maintenance of the negative pressure, it is proposed to produce all parts of the heat sink from thin-walled stainless steel. In the example shown, the heat sink 30 as a shaped body 24 the shape of a flat plate 240 on.

2 shows a solar thermal collector 31 as a flat collector 310 which is in a collector housing 32 is integrated. This is the two-phase thermosiphon 1 as a sandwich element 2 backward through a tub 321 with an inserted vacuum insulation panel as thermal insulation 322 and a transparent enveloping element 33 in the form of a vacuum insulating glass pane 331 Protected against heat loss on the side facing the sun. In order to achieve an optimal energy yield with changing irradiation angles of the sun, the surfaces of the VIG disks are 331 antireflective and can with a light-directing structure, for. B. in the form of light-directing prisms 330 be provided. A surrounding frame 320 serves for installation in a building envelope construction. The sandwich element 2 consists of a front, sun-oriented cover shell 20 and a rear cover 21 , Line-shaped spacers 22 that as ribs 220 are formed, together with the cover shells 20 . 21 one in chambers 100 . 101 subdivided working space 10 , About a swamp 110 , which is the liquid working medium 11 which are supported by a flow guide 102 separate chambers 100 . 101 in connection with each other. Here, the sun facing the flow chamber 100 the rise of the gaseous working medium in the operating state 11 and directs the working fluid to the condenser 13 , which at the upper end of the working space of the heat transfer tube 25 is formed. Return chambers 101 serve on the opposite side of the sun Page the reflux of the condensate in the sump 110 , So the working medium 11 already at a temperature below 25 ° C in the gas phase 111 passes, prevails in the sandwich element 2 a negative pressure of about 5 Pascal. The working surface rigidly aligned with solar radiation 12 carries an absorbent, selectively effective coating 120 , Over a not shown, convex or concave structured surface of the cover shells 20 . 21 For example, the absorption and conversion of solar radiation into heat and the dimensional stability at varying operating pressures can be improved.

3 shows a solar thermal collector 31 that as a flat plate collector 310 in the form of a pivotable about a horizontal axis x lamella 241 is trained. The as sandwich element 2 trained two-phase thermosiphon 1 corresponds in construction and operation to the in 1 described embodiment. As the working medium 11 in the operating state of the solar thermal collector 31 Temperatures reaching 100 ° C and above, is a saturated hydrocarbon from the group of alkanes as the working medium 11 proposed. To the heat losses during outdoor installation of the flat collector 310 To keep as low as possible, the lamella 241 from a transparent wrapping element 33 surround. By means of spacers, not shown, the hollow chamber plate 332 Made of polycarbonate protected against overheating and at a distance to the cover shells 20 . 21 held, so that an additional insulating air layer between the sandwich element 2 and the atmosphere is formed. The slat 241 is an element within a lamellar register, which is mounted as a sunshade in front of a facade, each lamella can be pivoted about a horizontal axis of rotation x and fixed in different working positions. In a rigid heat transfer tube 25 the slat turns 241 around the pipe 25 , wherein the heat transfer to the heat transfer tube 25 by a silicone oil as a hinge between the movable blade 241 and the rigid tube 25 serves. Turn the heat transfer tube 25 and the slat 241 together, not shown waterproof joints on the pivot axis x are required.

4 shows a solar thermal flat collector 310 as a large-area heat exchanger 3 which is almost entirely made of glass. The sun-facing cover shell 20 and the back cover 21 are each as vacuum insulating glass panes 331 formed, with the sun-oriented cover shell 20 on the workroom 10 facing surface an absorbing and selectively effective coating 120 wearing. Between the two cover shells 20 . 21 is the workroom 10 a two-phase thermosyphone 1 , A vacuum with a residual pressure of about 5 Pascal leaves the working medium already at a temperature of 22-25 ° C in the gas phase 111 go over and rise to the heat sink, where the heat transfer tube 25 as a capacitor 13 is effective. A capillary structure 140 stands as a wick 14 with the swamp 110 in contact and brings the working medium 11 in a thermally conductive contact with the selective coating 120 so that the evaporation process and thus the heat transfer starts at a surface temperature of approx. 22-25 ° C. The edge bond of the workspace 10 is formed by a thin-walled stainless steel foil, which by means of a glass-metal connection with the VIG discs 331 is connected vacuum-tight. A circumferential, belonging to the outside edge profile forms the frictional connection between the two cover shells 20 . 21 , Inside the workroom 10 themselves are punctiform spacers 23 provided, which are formed as metal pins and in the same grid as the spacers of the VIG disks 331 are arranged. This flat collector 310 is intended as an element of a building envelope construction and combines the functions of a heat-insulating facade panel with the collector function and can also be designed to be translucent. In a variant of this heat exchanger 3 It is intended to use a single pane of glass on the room side and the two-phase thermosyphone 1 then as a heat sink 30 to operate the air conditioning of an adjacent room.

5 shows a vacuum tube collector 311 in which a heat exchanger according to the invention 3 as solar thermal collector 31 in the form of a pivotable about a horizontal axis of rotation x slat 241 in a glass tube 333 is arranged. By means of a non-illustrated glass-to-metal connection is the glass tube 333 closed at both ends vacuum-tight and is on its outside of a transparent, splinter-binding film 334 surround. The sandwich element 2 is made of two cover shells 20 . 21 constructed, each having on its surface an absorbent coating 120 wear. The heat transfer tube 25 is arranged coaxially and concentrically to the pivot axis x and forms with its outer lateral surface the capacitor 13 for the working medium 11 , which is in the inactive state of the vacuum tube collector in a sump 110 at the lower end of the lamella 241 collects. ribs 220 connect as linear spacers 22 the cover shells 20 . 21 with each other and with the heat transfer tube 25 , An unspecified, fixed concave mirror outside the glass tube 333 can increase the efficiency. In addition to a very effective and without delay working heat transfer, this two-phase thermosiphon 1 In contrast to conventional, copper-based solutions are made entirely from thin-walled steel sheets. Corresponding tube collectors 311 are particularly suitable for integration into a facade construction and can be used as horizontally swiveling elements in addition to the Serve sunscreen.

6 shows a horizontally arranged, rigidly oriented to the sun, solar thermal vacuum tube collector 311 in which the heat exchanger 3 in a glass tube 333 is arranged. Non-illustrated end connections close the glass tube 333 vacuum-tight, wherein at the closed end of a glass closure and at the open end of a vacuum-tight glass-metal closure for carrying out flow and return 260 . 261 a large-area two-phase thermosyphone 1 are provided. The cover shells 20 . 21 a sandwich element 2 are with an absorbent coating 120 provided that the sunlight as direct incident radiation and indirectly via a concave mirror 34 is caught in involute form. The heat exchanger 3 is as a sandwich element 2 constructed, with the cover shells 20 . 21 through a thin profile sheet 221 are interconnected. The particular advantage of this arrangement is that a heat exchanger 3 in this way in a horizontally arranged vacuum tube collector 311 can be installed, the two-phase thermosiphon 1 works perpendicular to the horizontal pivot axis x. Another advantage is that the return 261 in heat-conductive contact with the sump 110 stops, causing the evaporation of the working fluid 11 is accelerated. Also in this embodiment, the working medium 11 in the gas phase 111 via flow chambers 100 and return chambers 101 controlled. The processing of extremely thin stainless steel sheets and foils promotes heat transfer through the two-phase thermosyphone 1 on the heat transfer fluid 26 and makes it possible to dispense with components made of copper.

7 shows a solar thermal tube collector 311 in which the heat exchanger 3 a cylindrical hollow body 242 has, the z. B. of two half-shell-shaped sandwich elements 2 is formed and concentric and coaxial about the focal line f of a surrounding concave mirror 34 is arranged. By pivoting about a vertical axis of rotation x, this collector arrangement can follow the changing azimuth angles of the sun. A heat transfer fluid 26 flows through the centrally arranged heat transfer tube 25 from bottom to top and traversed at the top of the heat exchanger 3 the workroom 10 , The outer surface of the heat transfer tube 25 forms in this area as a capacitor 13 the heat sink of the two-phase thermosyphon 1 , In the chambers 100 of the workroom 10 falls the working medium 11 as condensate in the swamp 110 at the lower end of the cylindrical hollow body 242 to heat over the work surface 12 in the gas phase 111 to ascend again. The cover shells 20 . 21 form the lateral surfaces of a cylindrical hollow body, in the region of the capacitor 13 flared funnel-shaped and with the heat transfer tube 25 connected is. In a particularly advantageous embodiment, the glass tube 330 made of antireflective borosilicate glass, has a diameter of 70 mm and a length of 4 m and is closed at both end faces by means of a glass-metal connection vacuum-tight. A tube collector 311 is preferably concentric with the focal line f of a parabolic concave mirror 34 arranged and can be used as a vertical solar thermal collector about four successively arranged heat exchanger 3 take up. If you abandon the vacuum in the glass tube 333 , there is a large choice in terms of pipe diameter, pipe length and material. Long tube collectors 311 are characterized by the advantage that the heat transfer tube 25 inside the heat-insulating glass tube 333 is arranged, whereby the heat losses are reduced and the insulation measures outside of the tube collector 311 are reduced to a minimum. Reference numeral Overview 1 Two-phase thermosyphon 2 sandwich element 3 heat exchangers 10 working space 20 Absorbing cover shell 30 heatsink 100 lead chamber 21 Rear cover shell 31 Solar thermal collector 101 Return chamber 22 Line-shaped spacers 310 flat-plate collectors 102 flow guide 220 ribs 311 Vacuum tube collector 11 working medium 221 Profilblech 32 collector housing 110 swamp 23 Point-shaped spacers 320 Surrounding 111 gas phase 24 moldings 321 tub 12 working surface 240 Level plate 322 thermal insulation 120 Absorbent coating 241 lamella 33 Transparent wrapping element 13 capacitor 242 Cylindrical hollow body 330 Light directing prisms 14 wick 25 Heat transfer tube 331 VIG disc 140 Capillary structure 250 longitudinal rib 332 Multiwall sheet 251 transverse rib 333 glass tube 26 Heat transfer fluid 334 protector 260 leader 34 concave mirror 261 returns f focal line x axis of rotation

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - DE 202008007647 [0003]
• - DE 102006000668 B4 [0004]
• - DE 202007007568 [0005]
• - DE 10308993 A1 [0006]

Claims (25)

Two-phase thermosiphon ( 1 ) as a heat exchanger ( 3 ) with a work surface ( 12 ) for absorption and transfer of heat to a heat transfer fluid ( 26 ), in which a relative to the atmosphere hermetically encapsulated and with a negative pressure ( 100 ) acted upon working space ( 10 ) for receiving a working medium ( 11 ), which is in the idle state of the heat exchanger ( 3 ) as a liquid in a sump ( 110 ) at the bottom of the workspace ( 10 is provided, wherein the two-phase thermosiphon ( 1 ) has a sheet-like expansion and as a sandwich element ( 2 ) a pressure-resistant, evacuable container of two cover shells ( 20 . 21 ) by spacers ( 22 . 23 ) are held at a distance and at their edges vacuum-tight with each other, forms, so over a large area of at least one of the cover shells ( 20 . 21 ) formed, effective as a heat source working surface ( 12 ) a continuous transfer of latent heat by the operating state gaseous working medium ( 11 ) on the outer surface of one in the working space ( 10 ) above the swamp ( 110 ) arranged centrally and by the heat transfer fluid ( 26 ) through which the heat transfer tube ( 25 ), used as a capacitor ( 13 ) evenly from the working medium ( 12 ) flows around takes place. Two-phase thermosiphon ( 1 ) according to claim 1, characterized in that a sandwich element ( 2 ) as a shaped body ( 24 ), z. B. in the form of a flat plate ( 240 ), a lamella ( 241 ), as a cylindrical hollow body ( 242 ) or formed as a free-form shell or hollow body. Two-phase thermosiphon ( 1 ) according to claim 1, characterized in that spacers ( 22 ), which shell with the deck ( 20 . 21 ) are connected in a line and z. B. from individual, parallel ribs ( 220 ) or profile sheets ( 221 ) consist. Two-phase thermosiphon ( 1 ) according to claim 1, characterized in that spacers ( 23 ) provided with the cover shells ( 20 . 21 ) are punctiform connected and z. B. are designed as pins or bolts or have a grid structure in the manner of a space frame. Two-phase thermosiphon ( 1 ) according to claim 1, characterized in that the cover shells ( 20 . 21 ) are folded at their edges, bent or beaded formed and directly or via an edge profile with each other to a vacuum-tight container for receiving the working medium ( 11 ) get connected. Two-phase thermosiphon ( 1 ) according to claim 1, characterized in that the cover shells ( 20 . 21 ) of a sandwich element ( 2 ) between the line or punctiform spacers ( 22 . 23 ) have concavely or convexly curved partial surfaces in order to compensate for the changing pressure stresses in the working space ( 10 ) of a two-phase thermosyphone ( 1 ) as dimensionally stable as possible. Two-phase thermosiphon ( 1 ) according to claim 1, characterized in that as a working medium ( 11 ) a liquid which evaporates under vacuum at temperatures below 25 ° C, such as. B. a mixture of water and ethanol, water and methanol or a saturated hydrocarbon from the group of alkanes, is provided, wherein the negative pressure in the working space ( 10 ) z. B. is less than or equal to 5 Pascal. Two-phase thermosiphon ( 1 ) according to claim 1, characterized in that the working space ( 10 ) at least one heat source facing the flow chamber ( 100 ), in which the working medium ( 11 ) in the gas phase ( 111 ), and a return chamber ( 101 ), in which the working medium ( 11 ) as condensate in the sump ( 110 ), whereby between the chambers ( 100 . 101 ) a flow control surface ( 102 ) is arranged. Two-phase thermosiphon ( 1 ) according to claim 1, characterized in that the working space ( 10 ) is formed as a contiguous space whose compartments over the swamp ( 110 ). Two-phase thermosiphon ( 1 ) according to claim 1, characterized in that the heat transfer tube ( 25 ) inside longitudinal ribs ( 250 ) and outside, with the working space ( 10 ) related transverse ribs ( 251 ) for optimum heat transfer to the heat transfer fluid ( 26 ) Has. Two-phase thermosiphon ( 1 ) according to claim 1, characterized in that the working space ( 10 ) one with the swamp ( 110 ) connected wick ( 14 ) with a capillary structure ( 140 ) receiving the working medium ( 11 ) in the lower section of a sandwich element ( 2 ) in a thermally conductive contact with the Working surface ( 12 ) brings. Two-phase thermosiphon ( 1 ) according to claim 1, characterized in that a heat transfer tube ( 25 ) a flow and return ( 250 . 251 ) and the return ( 251 ) in heat-conducting contact with the sump ( 110 ) of a two-phase thermosyphone ( 1 ) stands. Two-phase thermosiphon ( 1 ) according to claim 1, characterized in that the heat exchanger ( 3 ) as a heat sink ( 30 ) whose working surface ( 12 ) is directly in communication with the surrounding room air and as an air conditioning undesired excess heat from the room air to a heat transfer fluid ( 34 ) transmits. Two-phase thermosiphon ( 1 ) according to claim 1, characterized in that a heat sink ( 30 ) is arranged in an interior space either on the room-side surface of an outer wall component or is attached to an inner wall and is thereby flushed on at least one side of the room air. Two-phase thermosiphon ( 1 ) according to claim 1, characterized in that a heat sink ( 30 ) the heat recovery from hot air or hot exhaust gases is used and z. B. is installed in a fireplace. Two-phase thermosiphon ( 1 ) according to claim 1, characterized in that the heat exchanger ( 3 ) as a solar thermal solar collector ( 31 ) and a work surface ( 12 ) a selectively effective coating absorbing the sunlight in the wavelength range of 0.3 to 1.8 microns ( 120 ) wearing. Two-phase thermosiphon ( 1 ) according to claim 1, characterized in that a solar thermal solar collector ( 31 ) a trans parentes envelope element ( 33 ), as a glass sheet, as an insulating glass pane, as VIG-pane ( 331 ), as a hollow chamber plate ( 332 ) or as a glass tube ( 333 ) is trained. Two-phase thermosiphon ( 1 ) according to claim 1, characterized in that the transparent enveloping element ( 33 ) in a rigidly solar-oriented solar collector ( 31 ) a light directing structure z. B. as a prism sheet ( 330 ) is formed. Two-phase thermosiphon ( 1 ) according to claim 1, characterized in that a flat collector ( 310 ) in a conventional collector housing ( 32 ) with transparent envelope ( 33 ), rear pan ( 321 ) for receiving the thermal insulation ( 322 ) and a Umfassungszarge ( 320 ) is installed. Two-phase thermosiphon ( 1 ) according to claim 1, characterized in that a flat collector ( 310 ) is integrated in the construction of a partially transparent insulating glass pane, wherein a sandwich element ( 2 ) several in series, by ribs ( 220 ) isolated working spaces ( 10 ) and the cover shells ( 20 . 21 ) in the area between the workspaces ( 10 ) are formed perforated for the passage of daylight. Two-phase thermosiphon ( 1 ) according to claim 1, characterized in that in a flat collector ( 310 ) both cover shells ( 20 . 21 ) of a sandwich element ( 2 ) as VIG disks ( 331 ) are formed, wherein punctiform spacers ( 23 ) in the same grid arrangement as the spacers of the VIG disks ( 321 ) the working space ( 10 ). Two-phase thermosiphon ( 1 ) according to claim 1, characterized in that in a flat collector ( 310 ) of glass one of the working space ( 10 ) facing surfaces of the VIG discs ( 331 ) an absorbent, selectively effective coating ( 120 ) wearing. Two-phase thermosiphon ( 1 ) according to claim 1, characterized in that a solar thermal collector ( 31 ) is aligned rigidly to the sun or by pivoting about an axis of rotation (x), z. B. as solar shading ( 241 ) can follow the different angles of incidence of the sun and is thereby fixable. Two-phase thermosiphon ( 1 ) according to claim 1, characterized in that a plurality of pivotable in a pivot axis (x) and alignable to the sun slats ( 241 ) form a lamellar register. Two-phase thermosiphon ( 1 ) according to claim 1, characterized in that a solar thermal collector ( 31 ) as a vacuum tube collector ( 311 ) is formed and coaxial and concentric with the Brenn line (f) of a concave mirror ( 34 ) is arranged.