US20130192793A1

US20130192793A1 - Device for temperature control of a room

Info

Publication number: US20130192793A1
Application number: US13/520,223
Authority: US
Inventors: Werner Guckert; Christian Kipfelsberger; Robert Michels; Siegfried Rauch
Original assignee: SGL Carbon SE
Current assignee: SGL Carbon SE
Priority date: 2009-12-31
Filing date: 2010-12-31
Publication date: 2013-08-01
Also published as: SG182296A1; EP2519783A1; WO2011080338A1; CA2786157C; EP2519783B1; PL2519783T3; CA2786157A1

Abstract

A device for tempering a room includes at least one component that forms a thermal accumulator and has a surface oriented towards the room. Tubes that are thermally coupled to the component can be traversed by a heating or cooling medium. The tubes are integrated into a panel that contains expanded graphite or is made of expanded graphite. The panel is in areal thermal contact with the surface of the component that faces towards the room.

Description

The invention relates to a device and a method for the temperature control of a room according to the preambles of claims 1 and 27.
So-called concrete core activation systems are known from the prior art for the air conditioning of rooms having concrete ceilings or concrete walls. In these systems pipes carrying heating or cooling media are mounted in, below or on the concrete ceiling or the concrete wall. By storing the heating or cooling energy in the concrete mass of the ceiling or the walls and a time-delayed delivery of the stored heating or cooling energy, an energy-efficient air conditioning of the rooms can be achieved. Thus, for example, at night a cooling fluid (for example, water) is cooled and passed through the pipes in a concrete core activated ceiling or wall whereby the ceiling or the wall is slowly cooled. The cooling energy stored in the concrete ceiling or wall can then be released into the room during the day in particular in the warm summer months, to slowly lower the room temperature in the room.
However, the installation of such thermally activatable ceilings or walls is restricted to new buildings. When renovating old buildings, such concrete core activation of the ceilings or walls cannot be installed subsequently. In the case of ceilings or walls with concrete core activation it is furthermore disadvantageous that pipes laid in the concrete ceiling or wall could be unintentionally damaged, for example, by the drilling of holes. Repair of damaged pipes is scarcely possible since the pipes embedded in concrete are difficult to access for a repair. The statics and the stability of ceilings or walls provided with pipes also suffer from the pipes embedded in concrete. Furthermore, the manufacture of such concrete core activation systems is very time consuming and costly. Another disadvantages lies in the inertia of the thermal system which is based on the time-delayed release of the thermal energy stored in the concrete accumulator mass to the room to be temperature controlled.
In order to eliminate these disadvantages, temperature control systems are known from the prior art which can also be provided subsequently on pipe-free ceilings or walls. These temperature control systems usually comprise ceiling or wall elements in which pipes are disposed which can be acted upon with a heating or cooling medium. These ceiling or wall elements are fixed to the ceiling or wall. The thermal energy stored in the heating or cooling medium which is passed through the pipes is diverted via a frame or a lining of the ceiling or wall elements in to the room to be temperature controlled by thermal radiation and free convection. Such a system is described for example in EP 1371915 A1 in which phase change materials are used as thermal accumulators.
These temperature control systems have the disadvantage that the thermal energy from the heating or cooling medium flowing into the pipelines is released directly and instantaneously by thermal radiation and convection into the room. In these temperature control systems the surfaces of the ceilings or the walls are also occupied by the ceiling or wall elements. This has the result that the ceiling or wall surface is thermally separated from the room to be temperature controlled which is why the mass of the ceilings or the walls cannot be used for storage cooling (or heating) in the night.
Starting from this, it is the object of the present invention to provide a device and a method for the temperature control of a room in which the mass of the ceilings or walls can be used as a thermal accumulator without pipes for the passage of a heating or cooling medium for thermal actuation of the accumulator needing to be incorporated in the ceilings or walls. It is furthermore the object of the invention to provide the most energy-efficient temperature control system with short response times. Furthermore, it should be made possible to install these temperature control systems subsequently, including when renovating old buildings.
These objects are solved with a device for the temperature control of a room having the features of claim 1 and by a method having the features of claim 27. Preferred embodiments of the device according to the invention can be deduced from subclaims 2 to 26.

The invention is explained in detail hereinafter by means of exemplary embodiments with reference to the accompanying drawings. In the drawings:

FIG. 1: shows a schematic sectional view of a device according to the invention for temperature control of a room in a first embodiment;

FIG. 2: shows a schematic sectional view of a ceiling or wall element for a temperature control device according to the invention in a second embodiment;

FIG. 3: shows a schematic sectional view of the second embodiment of a temperature control device according to the invention with the ceiling or wall element from FIG. 2.

FIG. 1 shows a first embodiment of a temperature control device according to the invention. This comprises an element 10 provided on a component 5 made of concrete or brick. The component 5 can comprise a ceiling or a wall or a floor of the room R to be temperature controlled. The component 5 can also be constructed from another conventional building material that is capable of storing heat and/or cold, such as clay or natural stone. The element 10 then accordingly comprises a ceiling, wall or a floor element which is disposed on the surface 11 of the component 5 pointing into the room. As a result of its large mass, the component 5 forms a thermal accumulator in which thermal energy (in the form of heat or cold) can be stored.
The element 10 comprises a panel 1 containing expanded graphite or consisting completely of expanded graphite.
The production of expanded graphite (expanded graphite) is known inter alia from U.S. Pat. No. 3,404,061-A. In order to produce expanded graphite, graphite intercalation compounds or graphite salts such as, for example, graphite hydrogen sulphate or graphite nitrate are heated in a shock manner. The volume of the graphite particles is thereby increased by a factor of about 200-400 and at the same time the bulk density decreases to values of 2-20 g/l. The expanded graphite thus obtained consists or worm- or concertina-shaped aggregates. If completely expanded graphite is compacted under the directional action of pressure, the layer planes of the graphite are preferably arranged perpendicular to the direction of action of the pressure, where the individual aggregates become entangled. In this way, self-supporting surface structures such as, for example, webs, plates or moulded bodies can be produced from expanded graphite.
In order to stiffen and increase the stability of these graphite panels or moulded bodies, the expanded graphite can be mixed with curing binders such as, for example, resins or plastics, in particular elastomers or duromers. In order improve the stability of panels made of expanded graphite, it is particularly suitable to mix the expanded graphite with thermoplastic and/or thermosetting plastics which can be introduced into the expanded graphite for example by impregnation or by means of a powder method. After the binder mixed with the expanded graphite has been cured, the graphite moulded bodies or plates made from these mixtures have a sufficient stability for the intended application provided according to the invention. The graphite panels produced in this way are in particular self-supporting and can readily be fixed to components such as ceilings or walls, for example by adhesive bonding or screwing.
Pure expanded graphite, in the same way as mixtures of expanded graphite with binders, has a very good thermal conductivity. The thermal conductivity of a mixture of expanded graphite with a binder is still very high with a 50 wt. % binder fraction according to the type of binder used. Insofar as graphite panels are mentioned in the following, these are understood as panels which either consist of pure expanded graphite or a mixture of expanded graphite with a binder.
It is also possible to manufacture graphite panels from mixtures of expanded graphite with phase-change materials (PCM, phase change materials). For this purpose, common phase-change materials, for example based on paraffin, wax or salt can be added during the manufacture of the graphite panels. Such a graphite panel with a phase-change material can be used in the temperature control systems according to the invention as additional thermal accumulators (latent heat accumulator) along with the component 5 acting as a thermal accumulator.
Pipes 9 are embedded in the graphite panel 1 shown in FIG. 1. The pipes 9 are preferably arranged in a serpentine shape in the interior of the panel 1. Other laying patterns of the pipes such as, for example, a spiral-shaped, grid-shaped or meander-shaped arrangement or an arrangement only in the edge zones of the panel 1 is feasible. The ends of the pipes 9 running in the panel 1 are connected to a conveying device for passing a heating or cooling medium (such as, for example, hot or cold water) through the pipes 9. In order to provide the entire surface 11 of the component 5 pointing into the room R with elements 10, a plurality of such elements 10 can be arranged behind one another or adjacent to one another and fixed on the surface 11. The ends of the pipes 9 of each element 10 are then connected to the associated ends of the adjacent elements 10 to form a pipe circuit and the pipe circuit is coupled to the conveying device for passage of the heating or cooling medium.
The fixing of the elements 10 is preferably accomplished by a thermally conducting adhesive 4, by which means one principal surface 12 of the panel is adhesively bonded to the surface 11 of the component 5. As a result of the adhesive bonding, the principal surface 12 of the panel 1 is in flat thermal contact with the surface 11 of the thermal accumulator formed by the component 5, preferably over the entire principal surface 12.
The other principal surface 13 of the panel 1 can be provided with a stiffening layer 6 as in the exemplary embodiment shown in FIG. 1. The stiffening layer 6 can for example comprise a plaster layer or a glued-on hard cardboard or plasterboard layer. Combinations of plaster layers and textile materials embedded therein such as, for example, nets, woven fabrics, knitted fabrics, crocheted fabrics or the like, are also possible. As a result of the stiffening layer 6, on the one hand the stability of the graphite panel 1 can be increased and on the other hand the principal surface 13 of the panel 1 pointing into the room R can be clad in a visually attractive manner. The application of a stiffening layer 6 is particularly appropriate for panels 1 made of pure expanded graphite (without added binder).
The pipes 9 running in the panel 1 can be incorporated during the manufacture of the graphite panel 1. The pipes 9 preferably comprise pipes made of metal, for example copper, or plastic pipes, for example made of polypropylene or cross-linked polyethylene. However pipes made of metal are to be preferred because of the better heat transfer. As shown in the exemplary embodiment in FIG. 1, The pipes 9 can be completely embedded in the panel 1. However, it is also possible to arrange the pipes 9 so that they end flush with a principal surface 12 or 13 of the panel 1.
For embedding the pipes 9 in the panel 1, during manufacture of the panel, the pipes 9 can be laid in the filling of worm- or concertina-shaped aggregates and this combination can be pressed in a known manner by action of pressure (for example by means of rollers or pressure plates) to form a dimensionally-stable graphite panel 1. In order to increase the stability of the panels, one of the aforementioned binders can be added during the production process. The graphite panels 1 thus produced with pipes 9 embedded therein typically have thicknesses between 8 and 50 mm. The density of the graphite panels 1 is usually in the range of 0.01 to 0.5 g/cm³(depending on the fraction of added binder). The graphite panels 1 have a thermal conductivity of 3 to 6 W/mK.
As a result of the good thermal conductivity of the graphite panel 1, a certain proportion of the thermal energy stored in a heating or cooling medium passed through the pipes 9 can initially be passed by heat conduction from the pipes 9 to the free principal surface 13 of the panel 1 and released from there by thermal radiation and free convection to the room R to be temperature controlled. This release of heat (or release of cold when a cooling medium is passed through the pipes) takes place very rapidly with the result that the room can be heated (or cooled) very rapidly. Another portion of the thermal energy stored in the heating or cooling medium is transferred by heat conduction from the pipes 9 via the heat conducting panel 1 to the thermal accumulator formed by the component 5. By this means, the thermal accumulator is heated (or cooled when a cooling medium is passed through the pipes). The thermal accumulator can then release the thus intermediately stored thermal energy in a time-delayed manner to the room, where the good thermal conductivity of the panel 1 ensures that this is accomplished largely free from losses. The heating (or cooling) of the room R accomplished in this manner takes place on a longer time scale (of a few hours). The temperature control system according to the invention is therefore able to bring the room R to be temperature controlled to a desired room temperature both rapidly and also slowly using the thermal accumulator. Thus for example, at night in summer the thermal accumulator can be cooled by passing a cooling medium (for example cold water) through the pipes 9. During the day the thermal accumulator can then be used for cooling the room by means of a time-delayed release of cold to the room.
In a corresponding manner, in winter during the day the temperature control system according to the invention can firstly be heated for instantaneous heating of the room by passing a heating medium through the pipes. At the same time the thermal accumulator is loaded with heat. At night the flow of the heating medium can be stopped since the time-delayed release of heat from the loaded thermal accumulator is sufficient to keep the room at a (lower) room temperature at night.
FIGS. 2 and 3 show another exemplary embodiment of a temperature control system according to the invention. The same or corresponding parts in FIGS. 2 and 3 are provided with the same reference numbers as in FIG. 1.
In the exemplary embodiment of a device according to the invention for the temperature control of a room R shown in FIG. 3, a ceiling element 10 is fixed to a component 5 formed as a concrete ceiling. The component 5 forms a thermal accumulator with the concrete mass of the ceiling as accumulator mass. The ceiling element 10 has a frame 2 which is fixed to the surface 11 of the component 5 pointing into the room R, in particular is screwed thereon. The frame 2 is configured as a cassette which is open on one side (i.e. its upper side). The frame 2 is preferably made of a thermally conductive material such as, for example a metal sheet. The frame 2 has a base plate 2 a and four side walls 2 b disposed thereon or formed integrally with the base plate 2 a. At least the base plate 2 a (and optionally also the side walls 2 b) is formed from a perforated sheet (i.e. a metal sheet with a perforation). A graphite panel 1 is inserted in the frame 2. The composition of the graphite panel 1 corresponds to the panel 1 of the exemplary embodiment from FIG. 1. As in this exemplary embodiment pipes 9 are also embedded in the graphite panel 1 and run there in a serpentine, grid, spiral or meander shape. The graphite panel 1 is preferably adhesively bonded flat on the surface 11 of the component 5 by means of a thermally conductive adhesive 4. The principal surface 12 of the graphite plate 1 is therefore expediently in thermal contact with the surface 11 of the component 5 over its entire surface. The adhesive layer 4 can however also be omitted (see below).
A non-woven fabric 3 and a graphite film 15 are preferably disposed between the base plate 2 a of the frame 2 and the graphite panel 1. The non-woven fabric 3 can for example comprise a glass fibre or a carbon fibre non-woven. In combination with the perforation of the base plate 2, the non-woven fabric 3 ensures good sound absorption of the ceiling element 10. The graphite film 15 comprises a thin film of expanded graphite. The thickness of the graphite film 15 is preferably between 0.05 mm and 3 mm, in particular between 0.2 and 3 mm.
The non-woven fabric 3 and the graphite film 15 disposed thereon preferably comprises a non-detachable composite which can be produced for example by calendering. Such a composite can particularly expediently be produced from a carbon fibre non-woven and a graphite film 15 of expanded graphite. When calendering a thin film of expanded graphite with a carbon fibre non-woven, the carbon particles of the non-woven surface and the surface of the graphite film become entangled with one another so that a firm and non-detachable composite is formed between the carbon fibre non-woven 3 and the graphite film 15. It is particularly appropriate to use a perforated graphite film 15. Perforation of the graphite film specifically increases its flexibility and thereby facilitates the handling of the film. Since graphite comprises a brittle material, there is the risk of the film tearing or breaking when handling thin films of expanded graphite. This risk can be reduced significantly by perforation of the graphite film 15.
FIG. 2 shows a sectional view of a ceiling element 10 such as can be used in the exemplary embodiment of the temperature control device according to the invention shown in FIG. 3. As can be seen from FIG. 2, the upper principal surface 12 of the graphite panel 1 projects over the upper edge 2 c of the side walls 2 b of the frame 2. When using such a ceiling element 10, the adhesive bonding of the graphite panel 1 to the surface 11 of the component 5 can be omitted. For fixing the ceiling element 10 to the component 5, the frame is specifically screwed onto the component 5. When screwing the frame 2 to the surface 11 of the component 5, the graphite panel 1 is compressed until the principal surface 12 of the panel 1 ends flush with the upper edge 2 c of the side walls 2 b of the frame. The compression of the graphite panel 1 is made possible by the deformability of the expanded graphite. The graphite material of the panel 1 compressed in the perpendicular direction to the surface 11 is expediently in thermal contact with the surface 11 over the entire principal surface 12 after fixing the ceiling element 10 to the component 5. As a result of the good deformability of the graphite material of the panel 1, unevennesses and protrusions in the surface 11 of the component 5 can also be compensated.
The arrangement of the ceiling element 10 or plurality of adjacent ceiling elements on the surface 11 of the component 5 corresponds to the exemplary embodiment of FIG. 1 described above. The mode of operation of the temperature control device of FIG. 3 is the same as in the exemplary embodiment of FIG. 1.

Claims

1-27. (canceled)

28. A device for controlling a temperature of a room, the device comprising:

at least one component forming a thermal accumulator, said component having a surface pointing toward the room;

a panel containing expanded graphite or consisting of expanded graphite disposed in areal and thermal contact with said surface of said at least one component; and

pipes embedded in said panel and thermally coupled to said component, said pipes being configured to conduct therethrough a heating or cooling medium.

29. The device according to claim 28, which comprises a layer of thermally conducting adhesive affixing said panel to said surface of said component.

30. The device according to claim 28, wherein said pipes extend in said panel along a serpentine path, in a grid shape, in a spiral shape, or in a meandering pattern.

31. The device according to claim 28, wherein said panel is in heat-conducting contact with said surface of said component over an entire principal surface facing said surface.

32. The device according to claim 28, wherein said panel has a density between 0.04 and 0.10 g/cm³.

33. The device according to claim 28, wherein said panel has a thermal conductivity of more than 2 W/mK.

34. The device according to claim 28, wherein said panel is made of a mixture of expanded graphite and a binder selected from the group consisting of a resin and a plastic.

35. The device according to claim 34, wherein a fraction of said binder is 5 to 50 wt.%.

36. The device according to claim 35, wherein the fraction of said binder lies between 8 and 12 wt.%.

37. The device according to claim 28, wherein said panel is formed of a mixture of expanded graphite and a latent heat storage material.

38. The device according to claim 37, wherein said latent heat storage material is a phase change material selected from the group consisting of salt, wax or paraffin.

39. The device according to claim 28, wherein said component comprises a concrete ceiling or concrete wall.

40. The device according to claim 28, wherein said panel is one of a plurality of panels with pipes embedded therein affixed adjacent to one another on said surface of said component.

41. The device according to claim 40, wherein said pipes from mutually adjacent panels are interconnected to form a pipe circuit and said pipe circuit is coupled to a conveying device for passing the heating or cooling medium through said pipes.

42. The device according to claim 28, which comprises a stiffening layer applied to a surface of said panel facing away from said component or on both surfaces of said panel.

43. The device according to claim 28, wherein said panel is a plate disposed in a frame fixed to said component.

44. The device according to claim 43, wherein said frame is made of a thermally conductive material.

45. The device according to claim 43, wherein said panel is glued in said frame.

46. The device according to claim 43, wherein said frame is a cassette that is open on one side.

47. The device according to claim 46, wherein said panel disposed in said cassette projects over a frame edge thereof on the open side of said cassette.

48. The device according to claim 43, wherein said frame is configured as a cassette with a perforated base plate.

49. The device according to claim 48, which further comprises a non-woven fabric and a perforated graphite film disposed between said base plate of said frame and said panel.

50. The device according to claim 49, wherein said graphite film is a film made of expanded graphite with a perforation.

51. The device according to claim 50, wherein said perforated graphite film is firmly connected to said non-woven fabric.

52. The device according to claim 49, wherein said non-woven fabric comprises a glass fiber non-woven or a carbon fiber non-woven.

53. The device according to claim 49, wherein said non-woven fabric comprises a carbon fiber non-woven calendered onto the perforated graphite film.

54. The device according to claim 28, wherein said panel with said pipes embedded therein is self-supporting.

55. A method for temperature control of a room bounded at least on one side by a component, the component having a surface pointing into the room and a mass of the component forms a thermal accumulator that is thermally coupled to pipes disposed for conducting therein a heating or cooling medium, the method which comprises:

providing the pipes embedded in a thermally conducting panel containing expanded graphite or consisting of expanded graphite and placing the panel is in flat thermal contact with the surface of the component pointing into the room; and

transferring at least a part of a thermal energy stored in the heating or cooling medium by heat conduction from the pipes via the thermally conducting panel to the thermal accumulator for intermediate storage, and delivering the thermal energy from the thermal accumulator to the room in a time-delayed manner.