Module for a heat pump
09829225 · 2017-11-28
Assignee
Inventors
- Thomas Schiehlen (Altheim, DE)
- Steffen Thiele (Freital, DE)
- Thomas Wolff (Münchberg, DE)
- Eberhard Zwittig (Hochdorf, DE)
- Hans-Heinrich Angermann (Stuttgart, DE)
- Roland Burk (Stuttgart, DE)
- Holger Schroth (Maulbronn, DE)
- Stefan Felber (Schwieberdingen, DE)
- Steffen Brunner (Weissach im Tal, DE)
Cpc classification
Y02A30/27
GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
Y02B30/00
GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
F25B15/025
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F25B2315/006
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F25B35/04
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F25B2315/002
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F25B17/08
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F25B37/00
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F25B39/026
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F28F2275/025
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
International classification
F25B15/00
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F25B17/08
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F25B30/04
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
Abstract
The invention relates to a module for a heat pump, comprising an adsorption-desorption region, wherein in the region a bundle of pipes through which fluid can flow is arranged and a housing encloses the pipe bundle and a movable working medium in a sealing manner, wherein a supporting structure forms a mechanical support of a wall of the housing against the action of an external pressure.
Claims
1. A module for a heat pump, comprising: a housing; an adsorption/desorption region, wherein in the adsorption/desorption region, a bundle of tubes through which fluid can flow is arranged; a supporting structure that forms a mechanical support for a wall of the housing against an action of an external pressure; a first tube sheet having first rim holes that each retain a first end of respective tubes of the bundle of tubes; and a second tube sheet having second rim holes that each retain a second end of the respective tubes of the bundle of tubes, wherein the housing encloses the bundle of tubes and a movable working medium in a sealing manner, and wherein the supporting structure is arranged parallel to a longitudinal extent of the bundle of tubes, the longitudinal extent of the bundle of tubes being a direction from the first end of the respective tubes to the second end of the respective tubes, such that the supporting structure extends from the first tube sheet to the second tube sheet.
2. The module as claimed in claim 1, further comprising a condensation/evaporation region that is provided in the housing and in which the bundle of tubes through which the fluid can flow is arranged, wherein the working medium is movable between the adsorption/desorption region and the condensation/evaporation region.
3. The module as claimed in claim 2, wherein in the condensation/evaporation region, there is no support by the bundle of tubes for an accumulation and release of the working medium.
4. The module as claimed in claim 2, wherein the adsorption/desorption region occupies a larger proportion of the module than the condensation/evaporation region, and wherein a ratio of the volumes taken up by each of these regions within the housing is between 2 and 4.
5. The module as claimed in claim 2, wherein the supporting structure is positioned between the adsorption/desorption region and the condensation/evaporation region.
6. The module as claimed in claim 5, further comprising a second supporting structure, the second supporting structure being positioned in the adsorption/desorption region.
7. The module as claimed in claim 1, further comprising an adsorber structure comprising: an adsorbent, wherein the working medium can be adsorbed and desorbed on the adsorbent, and the adsorbent is thermally connected to at least one tube of the bundle of tubes in the adsorption/desorption region, wherein the adsorbent is formed as at least one shaped body which directly adjoins a tube wall of the at least one tube of the bundle of tubes.
8. The module as claimed in claim 7, wherein the at least one shaped body forms a mechanical support for a wall of the housing against the action of the external pressure.
9. The module as claimed in claim 7, wherein the at least one shaped body rests against the tube wall of the at least one tube of the bundle of tubes under the action of a force by frictional engagement.
10. The module as claimed in claim 9, wherein at least one of the two, namely the tube or the shaped body, has a substantially wedge-shaped cross section, wherein, in particular, at least one of the two is held under the action of a force in a wedging direction.
11. The module as claimed in claim 7, wherein the at least one tube of the bundle of tubes is designed as a flat tube and the at least one shaped body adjoins a broad side of the flat tube.
12. The module as claimed in claim 7, wherein the tube is designed substantially as a round tube or polygonal tube, wherein the tube is embedded in two or more shaped bodies.
13. The module as claimed in claim 7, wherein the flat tube is composed of an iron-based alloy which is coated for the purpose of joining and/or for corrosion resistance.
14. The module as claimed in claim 13, wherein the shaped bodies in which the tube is embedded have a polygonal, in particular hexagonal, external outline overall.
15. The module as claimed in claim 14, wherein the shaped bodies are adhesively bonded to the tubes by means of a thermoplastic adhesive, e.g. a silicone-based adhesive.
16. The module as claimed in claim 15, wherein the adhesive has a low density of uncrosslinked molecules.
17. The module as claimed in claim 13, wherein the shaped body is of substantially plate-shaped design, wherein it has in each case a plurality of indentations for partially surrounding some of the tubes.
18. The module as claimed in claim 1, wherein the housing wall is composed of an iron-based alloy, and wherein the housing wall is painted on the outside.
19. The module as claimed in claim 1, wherein no Ti-stabilized steels and/or stainless steels are used in assembling a tube/sheet and a sheet/housing joint by soft soldering.
20. The module as claimed in claim 1, wherein the housing is embodied as a single-shell housing formed by hydroforming.
21. The module as claimed in claim 7, wherein the at least one shaped body is a plate-shaped body.
22. A module for a heat pump, comprising: a housing; an adsorption/desorption region, wherein in the adsorption/desorption region, a bundle of tubes through which fluid can flow is arranged; and a supporting structure that forms a mechanical support for a wall of the housing against an action of an external pressure, wherein the housing encloses the bundle of tubes and a movable working medium in a sealing manner, and wherein the supporting structure is arranged parallel to a longitudinal extent of the bundle of tubes, the module further comprising an adsorber structure comprising: an adsorbent, wherein the working medium can be adsorbed and desorbed on the adsorbent, and the adsorbent is thermally connected to at least one tube of the bundle of tubes in the adsorption/desorption region, wherein the adsorbent is formed as at least one shaped body which directly adjoins a tube wall of the at least one tube of the bundle of tubes, wherein the at least one shaped body is a plate-shaped body, and wherein an upper surface of the plate-shaped body has first recesses that form steam ducts and a lower surface of the plate-shaped body has second recesses that form predetermined breaking points.
23. A module for a heat pump, comprising: a housing; an adsorption/desorption region, wherein in the adsorption/desorption region, a bundle of tubes through which fluid can flow is arranged; and a supporting structure that forms a mechanical support for a wall of the housing against an action of an external pressure, wherein the housing encloses the bundle of tubes and a movable working medium in a sealing manner, and wherein the supporting structure is arranged parallel to a longitudinal extent of the bundle of tubes the module further comprising an adsorber structure comprising: an adsorbent, wherein the working medium can be adsorbed and desorbed on the adsorbent, and the adsorbent is thermally connected to at least one tube of the bundle of tubes in the adsorption/desorption region, wherein the adsorbent is formed as at least one shaped body which directly adjoins a tube wall of the at least one tube of the bundle of tubes, wherein the adsorbent is formed as multiple shaped bodies, each of the multiple shaped bodies being a plate-shaped body, wherein the at least one tube of the bundle of tubes is designed as a flat tube, and wherein a first one of the plate-shaped bodies adjoins a first broad side of the flat tube and a second one of the plate-shaped bodies adjoins a second broad side of the flat tube.
Description
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(22) The module shown in
(23) Here, the tubes 4 of the first region are each designed as an adsorber structure 5 (see
(24) An adhesive layer 7 for connecting the shaped bodies 6 to the tubes 4 comprises a flexible adhesive based on silicone, in the present case Semicosil 988.
(25) Recesses 6a, 6b are formed in the shaped bodies, serving as steam ducts 6a for the joint supply and discharge of working medium and/or as predetermined breaking points 6b, by means of which separation of the shaped bodies from the tube 4 under excessive thermal stress is avoided.
(26) The tubes 4 project beyond the shaped bodies 6 in end regions 4a and open into rim holes 10a in tube sheets 10. The latter are embodied in such a way that they can flexibly accommodate thermomechanical differences in expansion between the housing parts, on the one hand, and the tubes, on the other hand. For this purpose, the tubes can also have one or more annular beads surrounding the rim hole region of the tube bundles.
(27) The flat tubes 4 can be of any desired design, being designed as a longitudinally laser-welded tube, snap over tube, B-type tube or flanged tube according to
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(29) In the example shown in
(30) In the example shown in
(31) In the illustrative embodiment shown in
(32) The round tubes 4 are each surrounded partially by a plurality of shaped bodies 6, in the present case two shaped bodies. Overall, the tube 4 is completely embedded in the shaped bodies 6 (apart from tolerance or adhesive bonding gaps), and overall they have a hexagonal external outline in the present case. As a result, the adsorber structures 5, each consisting of one tube 4 and two shaped bodies 6, can be stacked densely in two directions in space (see
(33) The preferred thickness of the shaped bodies 6 is obtained from the average length of the heat conduction path, for which the same specifications apply in the case of all the shapes (preferably between 1 mm and 10 mm, particularly preferably between 2 mm and 6 mm).
(34) As is apparent, the edges of the external outline of the shaped bodies have a defined rounding, and therefore respective steam ducts 6a are formed in the stack.
(35) Additional steam ducts extending transversely to the longitudinal axis of the tubes can be formed by segmenting the shaped bodies in the longitudinal direction of the tubes and spacing the segments apart (not shown).
(36) Depending on the requirements, the example shown in
(37) In the example shown in
(38) The shaped bodies 6 each have recesses 6a, 6b to form steam ducts and predetermined breaking points. It is self-evident that a recess 6a, 6b can also perform both functions simultaneously. They are preferably formed and arranged either in the neutral plane of the heat flux and/or as narrow gaps in the direction of heat flux.
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(40) In general, the adsorber structures described above preferably have the following properties:
(41) The tubes of the bundles are connected to the shaped bodies in a manner which allows good heat conduction, with overlaps of the ends being from 5 mm to 15 mm.
(42) The tubes of the tube bundles are characterized by:
(43) the base material being an iron-based material, particularly preferably ferritic stainless steel; this has a lower coefficient of thermal expansion than austenitic stainless steels.
(44) As an alternative, tinplated stainless steel or tinplated steel (tinplate) can be used as a raw material—depending on the joining method chosen. Another variant is to use galvanized base material, in particular galvanized steel. Using noncorrosive working media on the inside of the module, such as methanol and heat transfer media containing corrosion inhibitors, also makes it possible to use inexpensive steels (structural steel). Moreover, said steels can also be additionally provided with corrosion protection on the outside by coating or painting only after the final material joining of the overall module.
(45) The flat tubes 4 (
(46) The round tubes (
(47) In particular, the shaped bodies of the illustrative embodiments described above preferably have features in accordance with the following examples or are preferably produced in the following manner:
EXAMPLE 1
(48) 1. Use of a highly porous adsorbent in powder form as an adsorption-active base material for adsorbing the selected working medium (in the present case methanol), having the following properties:
(49) 1.1. Preferably having an adsorption isotherm of type 1.
(50) 2. Adsorber compound consisting of:
(51) 2.1. Powder of the sorption-active base material with a particle size in a range between 2 μm and 500 μm, preferably between 5 μm and 100 μm.
(52) 2.2. Ceramic binder based on siliceous ceramics such as magnesium silicates (e.g. steatite), magnesium aluminum silicates (e.g. cordierite) and aluminum silicates (e.g. stoneware, porcelain). The percentage by weight of the ceramic binder in the shaped body is between 5% and 50%, particularly preferably between 15% and 30%.
(53) 2.3. Heat-conducting additives, especially expanded graphite, BN, SiC, AlN, the percentage by mass being between 5% and 50%, preferably 10% to 35%.
(54) 2.4. Optionally inorganic fibers for reinforcement and increasing thermal conductivity.
(55) 2.5. Optionally activated carbon fibers, which both have sorptive properties and can perform a heat conducting function.
(56) 3. Shaped bodies produced from adsorber compound by the following method:
(57) Version 1:
(58) 3.1. Production of a plastic composition consisting of the components listed in 1., 2. above, plus water and a plasticizer.
(59) 3.2. Extrusion, e.g. to give a film or a strand which is rolled to give a film, into which channels, grooves or blind holes are rolled, followed by cutting.
(60) 3.3. Alternatively, extrusion to give a film with the profile already provided, having channels or grooves to improve mass transfer, followed by cutting into strips.
(61) 3.4. Drying according to requirements, with measures to maintain the shape.
(62) 3.5. Sintering in an inert gas atmosphere at a temperature and for a dwell time that are required for the hardening or sintering of the aluminum silicate binder to give a stable matrix.
(63) Version 2:
(64) Production of granules consisting of the components listed above and of an additive (e.g. a wax), which performs the function of a green binder after a pressing operation. One example of such a production process is the production of spray granules.
(65) 3.6. Introduction of the granules into a mold and pressing to give the shape of the adsorber structure.
(66) 3.7. Sintering in an inert gas atmosphere at a temperature and for a dwell time that are required for the hardening or sintering of the aluminum silicate binder to give a stable matrix.
(67) 3.8. To establish a particular porosity and a defined pore structure, a pore former, e.g. in the form of powdered polymers or in the form of organic fibers, can optionally be added to the starting mixture.
(68) The following features are preferably provided for the geometrical configuration of the shaped bodies:
(69) A plate shape with a thickness in a range between 1 mm and 10 mm, preferably in a range between 2 and 6 mm.
(70) A channel structure on one or both sides with a channel spacing that correlates with the plate thickness by a factor of between 0.5 and 2. A channel width is <1 mm, preferably <0.5 mm.
(71) A channel depth which correlates with the plate thickness by a factor of between 0.2 and 0.8.
(72) The following features are preferably present in respect of the adhesive layer 7 for attaching the shaped bodies 6 to tubes 4:
(73) flexible adhesive layer characterized by: full-surface wetting of the contact surface between the adsorption body and the metal support; optional partial usage of the channel volume as an adhesive displacement volume for achieving thin adhesive layers; temperature stability up to 250° C. for the purpose of adsorber desorption before installation; long-term stability relative to the working medium, preferably methanol, up to 130° C.; enrichment with heat conduction additives such as BN, finely ground graphite, expanded graphite or soot, depending on requirements; elongation at tear (elongation at break) at room temperature is at least 300%
(74) a layer thickness of the adhesive layer is between 10 μm and 500 μm, preferably between 50 μm and 150 μm.
(75) The heat transfer fluid flowing through the tubes 4 is a matter of free choice, but is preferably a water/propylene glycol mixture.
(76) The heat pump module shown in
(77) The housing 1 of the module comprises a lower housing part 1a and an upper housing part 1b, which each have stamped longitudinal beads in a first direction (direction of through flow) for reinforcement.
(78) The housing 1 furthermore comprises the sheets 10 with the rim holes 10a, into which the tubes 4 are inserted. The edges of the sheets are surrounded in a hermetically sealed manner by the two housing parts 1a, 1b.
(79) Respective supporting structures 11 are provided between housing parts 1a, 1b and the first and second regions 2, 3. The supporting structures 11 are of extended-area design, being designed in the present case as trapezoidal sheets (see, in particular,
(80) Overall, the crisscrossing of the longitudinal beads and of the folds results in a high pressure stability of the housing walls, especially in respect of external excess pressure and good thermal decoupling between the internal structures and the housing parts.
(81) The stacked adsorber structures 5 in the first region represent a further support. At least at operating temperatures and/or under a corresponding pressure effect (assembly with the minimum clearance necessary), the shaped bodies 6 rest perpendicularly one upon the other and on the trapezoidal sheets of the housing, resulting in optimum support with respect to the generally relatively high external pressure.
(82) The sheets 10 are provided from the outside with plastic header tanks 12 of the kind which are known in principle from the construction of heat exchangers. The header tanks 12 have connections 12a for supplying and discharging heat transfer fluid.
(83) Connections 13 for filling the module with working medium, in the present case methanol, are provided in the sheets 10. In the illustration in
(84) A supporting frame 15 is arranged in the module between the first region 2 and the second region 3 in order to further improve mechanical stability, especially in the vicinity of the second region 3. In general, in contrast to the adsorber structures 5 of the first region 2, no provision is made for the active structures for evaporation and condensation of the second region to rest upon one another in the manner of a mechanical support. This prevents condensed working medium from flowing down from the top between the structures.
(85) Another particularly preferred further embodiment has the following differing features in accordance with
(86) The direction of the housing beads of the two half shells is rotated through 90° and divided into three segments, between which there are undeformed flat housing surfaces.
(87) In the region of the undeformed flat surfaces, the housing shells are supported internally by a total of two supporting frames, which have tabs which pass partially through the housing shells. These tabs are welded materially and in a hermetically sealed manner to the housing parts afterwards from the outside, the advantage being that this embodiment can absorb even relatively high excess pressures without damage.
(88) The embodiment shown by way of example, having two supporting frames, in combination with the modified structure of the housing half shells, makes it possible to eliminate the trapezoidal sheets and hence to reduce the internal surface area and the mass of the housing.
(89) The following features preferably apply to the construction of the module and, specifically, to the housing 1:
(90) Both tube bundles of regions 2, 3 open at the ends into the tube sheets 10 and are connected materially thereto. The tube sheets have the following features:
(91) A metal base material with low heat conduction, preferably austenitic stainless steel, such as 1.4301 or 1.4404. A thickness range of the tube sheet is between 0.3 mm and 1.5 mm, preferably between 0.5 and 1 mm. Depending on the tube production method and joining method used, tinplated or galvanized base materials or uncoated inexpensive steels can also be used.
(92) Spacing of the tube sheet leadthroughs for thermal decoupling of the two regions 2, 3 in accordance with the thermal conductivity of the tube sheets is provided (adiabatic zone 16). As an alternative, however, the tube sheet can also be provided with a stamped transverse bead to reduce heat conduction losses between the regions.
(93) The tube sheets 10 have integrally formed tube rim holes 10a and have an optional coating, which is matched to the type of tube used and to the fluidtight joining method implemented, e.g. a layer of tin in the case of joining by means of soft soldering.
(94) A fluidtight tube/sheet connection can be produced by remote laser welding, characterized by: punching and push-through formation of a collar of the same height (
(95) As an alternative or supplementary measure, a fluidtight tube/sheet connection can be achieved by soft soldering, characterized by: use of one of the tubes illustrated in
(96) As an alternative or supplementary measure, a fluidtight tube/sheet connection can be achieved by adhesive bonding, characterized by: use of flat tubes (
(97) The housing 1 of the hollow element is preferably characterized by: base material consisting of stainless steel, preferably austenitic; shell-type construction comprising two housing parts 1a, 1b having; longitudinal beads in the direction of the longitudinal axes of the tubes, running out toward the rim; flat rim for material, fluidtight connection to the tube sheets 10 by flanged butt welding, soft soldering and/or adhesive bonding; U-shaped seam on one of the longitudinal edges in each case (longitudinal edge reinforcement and splash guard during optional laser welding);
(98) As a particularly preferred option, there is a reinforcement by a trapezoidal sheet 11 with a seam edge direction perpendicular to the external beading, characterized by: trapezium height adjusted for support of the inner trapezium surfaces on the adsorber structure; recesses for 90°-forming toward the side faces; spot welding to the outer shells; the housing half shells 1a, 1b are preferably connected to one another materially and hermetically by through-welding the upper and lower sheet by means of deep penetration laser welding, the sheet/housing connection is made by flanged butt welding; optional additional sealing is effected by means of a sealing adhesive in the bonding gap 17 (
(99) The supporting frame 15 is arranged in the region of the adiabatic zone 16 between the sorption zone 2 and the phase change zone 3 and is preferably characterized by: frame with bars angled in a U or L shape; frame height matched to the clear width between the inner surfaces of the trapezoidal sheet.
(100) The connections 13, 14 for evacuation and filling preferably comprise stainless steel or copper stubs which are welded into the tube sheet by means of resistance welding and into which respective evacuation and filling tubes made of copper are soldered for pinching off, ultrasonic welding and/or soldering shut.
(101) As an alternative, they can be stainless steel fittings which are screwed into the stubs and sealed off by means of metal gaskets and into which an evacuation/filling tube made of copper is soldered for pinching off and soldering shut or ultrasonic welding.
(102) The header tanks 12 preferably comprise an injection molded plastic inner part substantially resistant to hydrolysis, preferably PA or PPS, having: an elastomer seal for sealing off with respect to the tube sheet; respective fluid connections; respective vent stubs;
(103) An optional contact pressure bell made of metal (not shown) can have: bell depth adjusted to provide support for the internal sealing plastic inner part; guides and supporting elements for straps; straps for pressing two opposite header tanks in each case against the tube sheets of the tube bundles for the sorption zone 2 and phase change zone 3; clamping bars with clamping screws for pressing two opposite header tanks on in each case.
(104)
(105) In this case, the tubes 4 of the first region are each designed as an adsorber structure 5. Here, the broad sides of the flat tubes 4 are each connected to a shaped body 6 over an extended area, in particular by an adhesive bond for example. The shaped body 6 is composed of a mixture of adsorbent, in the present case activated carbon, and binder.
(106) Recesses 6a, 6b are formed in the shaped bodies, serving as steam ducts 6a for the joint supply and discharge of working medium and/or as predetermined breaking points 6b, by means of which separation of the shaped bodies from the tube 4 under excessive thermal stress is avoided.
(107) The tubes 4 project beyond the shaped bodies 6 in end regions 4a and open into rim holes 10a in tube sheets 10. The latter are embodied in such a way that they can flexibly accommodate thermomechanical differences in expansion between the housing parts, on the one hand, and the tubes, on the other hand. For this purpose, the tubes can also have one or more annular beads surrounding the rim hole region of the tube bundles.
(108) The two supporting elements 15 are arranged parallel to the longitudinal extent of the tubes 4, which support two housing half shells 1a, 1b provided with transverse beads on one another. Alternative detail designs of the supporting structure are possible, e.g. as a grid, a plurality of rods and the like.
(109) In another embodiment of the invention, in accordance with