EP3118533A1 - Ceiling element, in particular heating and cooling ceiling element on an aluminium or steel basis - Google Patents

Abstract

The present invention relates to a ceiling element made of or with a metal plate selected from aluminum and / or aluminum alloy plates, steel, tinplate and stainless steel, the side facing the space having a layer such that the plate on this side in the thermal infrared radiation (2.0 to 50μm) thermal emission at 100 ° C according to ISO 22975-3: 2014; Annex A.2 has at least 50% and its side facing away from the space is formed by the metal of the plate itself, which has no coating except a possible natural oxide skin in the case of plates made of aluminum and / or an aluminum alloy. Furthermore, the invention relates to a heat and / or cooling ceiling element, comprising such a ceiling element and at least one back mounted on this ceiling element tube, which is designed for the circulation of a heat transfer medium.

Description

The present invention relates to a ceiling element whose surface facing the space may be colored and / or mirrored and may have a surface with different degrees of roughness. The ceiling element is configured on the rear side in such a way that it can be connected particularly effectively to one or more pipes attached to the element, in which a heat transfer medium circulates, so that it can be used, in particular, as a highly efficient heating and / or cooling ceiling element.

With a cooling or heating blanket, heat should be dissipated from rooms within a building in order to individually air-condition these rooms. In addition, other functions such as the acoustic design, fire protection or lighting can be integrated into the ceiling elements. In addition, the ceiling elements also serve the architectural space design, so that in addition to the technical functions high aesthetic demands are placed on the ceiling elements.

In cooling mode, the heat from the room is transported by infrared radiation or by thermal convection to the ceiling. Up to 2/3 of the heat is transported by infrared radiation and the rest mainly by convection. It is therefore important that a cooling ceiling absorbs infrared radiation as well as possible. This is achieved by a surface with high thermal emission, since according to the Kirchhoff radiation law then also a high absorption of the infrared radiation is achieved. In the case of cooling ceilings with high levels of radiation, the perceived room temperature is 1.5 - 2 K below the room air temperature, which has a positive effect on comfort. Last but not least, humans release about 50% of their excess heat from radiation onto surrounding surfaces. Thus, a cooling ceiling system on the basis of the radiation cooling of the physiological heat output of humans comes.

In heating mode, the heat introduced via the heat transfer fluid is transferred to the ceiling element and discharged mainly as infrared radiation to the room. Therefore, it is also important in this case that the surface of the ceiling element has a high thermal emission in order to achieve a high radiation of infrared radiation. Also, this heat radiation is perceived by people as particularly pleasant.

Various heating and cooling ceiling elements are known from the prior art. Their main elements are a ceiling plate and coils, the back, so on their side facing away from the room, are fixed to the ceiling plate so that in the heating mode as much heat from a circulating in the pipes heating medium in the ceiling plate and in the Cooling mode as much heat from the ceiling plate in the then acting as a cooling medium in the tubes can pass.

As ceiling tiles here are often used plasterboard, but sometimes metal plates.

In DE 100 61 229 C1 is described consisting of ceiling panels and a supporting structure ceiling, which carries by a heating or cooling medium durchströmmbare tubular plastic conduits, wherein the tubular conduits are surrounded by a thin, thermally conductive copper foil, which is in contact with the ceiling plates facing away from half of the tubular conduits and forms a flat contact with the ceiling panels. By laid around the wires and rolled onto the ceiling plate copper foil to get large contact surfaces, which reduce the thermal resistance.

This in DE 298 03 663 U1 disclosed cooling ceiling module consists of a cladding Deckenpaneel and a cooling system, which consists of stapled on the inside of the ceiling panel pipe hammer. The pipe coils are covered with a metal sheet, which has a bead receiving or enclosing the bead as well as surface areas extending laterally therefrom. These areas are glued to the ceiling panel. By this construction, the heat absorbed by the ceiling panel is received over the sheet surface and effectively dissipated to the pipes.

With the heat transfer of a radiation plate deals JP 2505246 B2 , The plate is made of stainless steel covered with an oxide layer obtained by treatment with chromic acid. On this oxide layer is a layer of a fluorine resin (polyvinyl fluoride: PVF), which absorbs only radiation with a wavelength of 8-14 microns. Through the thickness of the oxide layer, the color of the plate surface is adjusted by interference. An improvement of the cooling and heating functions succeeds according to JPS 6352296 (B2) in that a rear plate is provided with recesses for water pipes, on the side facing away from the room, a heat-insulating material and on the side facing the room a plate with selectively radiating Surface coating is attached, which is in contact with the plate and the water pipes. The selective radiating surface coating consists of a two-ply coating wherein the inner layer consists of a high-reflectance layer of visible radiation, for example aluminum, and the outer layer of a material which is transparent to visible light but highly absorbent to IR radiation , for example, magnesium oxide.

Out WO 2011/128118 A1 It is known pipes of a liquid-carrying piping system by an ultrasonic welding process with an absorber sheet of a Solar collector to connect without the effective surface of the solar collector is impaired. For this purpose, a metal sheet is placed in an omega shape around the pipe and welded to the absorber sheet with the help of two sonotrodes.

The inventors of the present invention have set themselves the task of providing a visually appealing ceiling element, which, when it is provided as a component of a heating or cooling ceiling element for a room, such as a living or working space, this heating or Cooling ceiling element gives a special energy efficiency.

The object is achieved in accordance with the invention by providing a ceiling element composed of a metal plate selected from aluminum plates (pure aluminum, preferably A1050 or better, or an aluminum alloy or a roll-clad material of pure aluminum and an aluminum alloy) and plates containing iron alloy , namely plates made of steel, tinplate and stainless steel, or has such a plate whose side facing the room is treated so that they in the range of thermal infrared radiation (2.0 to 50 microns), a thermal emission at 100 ° C surface temperature according to ISO 22975-3: 2014; Annex A.2 of at least 50%.

If plates made of aluminum or an aluminum alloy are used, in a first embodiment of the invention the required thermal emission can be achieved by applying an aluminum oxide layer having a thickness of at least 1 .mu.m to the plate, it being possible to produce this layer by anodizing the aluminum surface. In this case, plates with different output roughness (eg with an R _a of 10 nm to 2 microns) can be used to obtain surfaces with different diffuse reflection ratio (between 5% and 95% according to DIN 5036-3). So you can adjust the surface appearance of the room from mirroring to matt. If, in addition, luminous elements are integrated into the ceiling elements, then the light distribution in the room can additionally be controlled. The aluminum may have been electrochemically polished in a first embodiment prior to anodizing, so that a high reflection with a low diffuse reflection component is achieved. In a second embodiment, this is omitted in order to achieve a high diffuse reflection component. Normally, a good aluminum mirror has a high reflection also in the area of thermal infrared radiation. By applying an anodization layer (eg of about 4 μm) on the aluminum plate used according to the invention, the high reflection (total reflection> 75% according to DIN 5036-3) is maintained in the visible range, but in the infrared range the reflection is considerably lowered by this measure, see above that the material receives the necessary high emission (in the example:> 70%) in order to absorb infrared radiation from the room as well as possible in cooling mode and on the other hand, in the heating mode, emit as much infrared radiation as possible to the room. This gives a selective coating with high thermal emission in the infrared and high reflection in the visible wavelength range.

In one embodiment of the invention, therefore, a ceiling element with a total reflection according to DIN 5036-3 of at least 70% and particularly preferably of at least 80% is provided.

The thickness of the anodization layer can be selected in a preferred manner in the range between 1 and 10 .mu.m, more preferably between 2 and 6 .mu.m. It influences the proportion of thermal emission which increases with increasing thickness of the layer. In FIG. 1 the dependence of the emission on the thickness of an aluminum oxide layer formed by anodization at different surface temperatures of the coated plate is shown. For example, the thermal emission of a plate surface which is hotter than 50 ° C increases from approx. 73% at 2 μm thickness to approx. 82% at 10 μm thickness.

When using this ceiling element made of aluminum or an aluminum alloy as the space-facing component of a heating or cooling ceiling of a room a particularly high energy efficiency is achieved because the anodized surface in the range of thermal infrared radiation (2.0 to 50 microns) an integral low reflection owns (see FIG. 2 ) and according to Kirchhoff's law and taking into account the energy conservation in this wavelength range thus a particularly high thermal emission (according to ISO 22975-3: 2014, Annex A.2) has.

In FIG. 2 is the reflection of aluminum applied with different anodization thicknesses. In addition, the emission of a blackbody at 15 ° C and 100 ° C in au (arbitrary units, freely selected units) is plotted. It can be seen from this that the reflection of the anodized aluminum surface in the region of the maximum of the emission curve is particularly small, which results in a high thermal emission.

The outer surface of the ceiling element according to the invention also has the advantage that can be added anodized aluminum surfaces with colored pigments, thereby obtaining colored surfaces. Thus, you can color the surface as desired and at the same time receives a surface with a high thermal emission.

For this purpose, the aluminum surface is first degreased chemically with caustic, usually in a caustic, strongly alkaline liquor and etched to remove the natural aluminum oxide layer of about 10nm thickness. This is followed, as an option, by electrochemical polishing followed by electrochemical anodizing in dilute Sulfuric acid. In the bath, the plate to be anodized is connected as an anode and a DC voltage of usually about 5 - 50V applied.

The cathode is usually made of lead. In the resulting stress field, oxygen-containing anions migrate to the aluminum surface. There they react with the aluminum surface, forming aluminum oxide, which due to its larger volume grows out of the original metal surface but remains firmly attached to the aluminum. In this case, capillary-like pores are formed in the alumina with a diameter of usually 10 nm to 50 nm. In these pores, inorganic or organic pigments can now be introduced by pulling the tape through a bath with a solution containing pigments with a defined concentration becomes. As inorganic pigment, for example, iron oxalate and as organic pigments, azo pigments are preferably used. As azo pigments are called organic pigments containing one or more azo groups -N = N-. The color intensity is determined not only by the concentration of the pigments but also by the thickness of the anodization layer. The thicker the anodization layer, the more pigments can be stored and the more intense the color impression. After incorporation of the pigments, the pores in the alumina are sealed in hot water so that the dyes are permanently embedded in the alumina layer.

Another advantage of the thick anodization layer is that the surface becomes very scratch-resistant by the hard alumina, so that all decorative applications on the surface are well protected against mechanical damage.

In a second embodiment of the invention, which can be realized with all usable metal plates, the space-facing side of the metal plate with a stoichiometric or substoichiometric silicon oxide coating, which is applied by means of the sol-gel process, and / or with a Fluoropolymer paint of at least 2 microns thickness coated. If plates of aluminum or an aluminum alloy are used in this embodiment, this side may or may not be anodized.

The thermal emission of the metallically clean surfaces of aluminum, steel, tinplate and stainless steel depends on the surface quality. For a polished surface, the thermal emission is below 10%, below 15% for a typical mill finish, and below 40% even for a sandblasted surface. This makes these materials for cooling and heating ceiling elements once poorly suited. According to the invention, however, it was found that the thermal emission at 100 ° C surface temperature according to ISO 22975-3: 2014; Annex A.2 can be increased to over 50% by coating with the aforementioned materials.

Fluoropolymer coatings are polymeric fluorohydrocarbons and contain carbon chains with perfluorinated carbon atoms. For the purposes of the invention are basically all polymeric fluorinated hydrocarbons, but those polymers are particularly preferred having having three fluorine atoms substituted ethylene units. These have hydrophobic properties which are particularly suitable for the invention. On the one hand, because of their higher substitution with fluorine over e.g. Polyvinylidene fluoride (with two fluorine atoms per ethylene unit) are preferred, but are also more favorable than completely perfluorinated materials such as Teflon. Particularly advantageous for the invention is the use of crosslinked or uncrosslinked fluoroethylene vinyl ether resins such as Lumiflon®, because the prepolymers have good solubility properties and the finished coatings show high transparency and flexibility. A crosslinking is usually carried out by the copolymerization of isocyanate groups, whereby crosslinked fluorourethane paints arise.

Sol-gel paints are produced by hydrolytic condensation of suitable silanes or polysiloxanes in a suitable solvent. In the solvent, a gel is formed with an already extensive network, so that after application of the resin or paint and removal of the solvent by heating or the like, a highly crosslinked three-dimensional SiO _x layer is formed.

The materials which can be used according to the invention not only impart the desired thermal emission properties; The additional benefit of these coatings is that the surface is well protected against environmental influences such as moisture and corrosive attack. This is especially important when using steel. In addition, an SiO _x coating produced by the sol-gel process is also very hard so that the surface is protected from mechanical damage. Fluoropolymer lacquer offers the additional advantage that the surface has hydrophobic properties, so that dirt is rejected well.

Both coatings have the advantage that they can be easily applied in an industrial coil coater on only one side of the sheet. In any case, the substrate, ie the metal plate, is preferably degreased on both sides prior to the coating in order to ensure good adhesion of the coating and later good ultrasonic weldability.

In order to additionally color the surface, the metal surface can also be coated with a colored layer before coating with a sol-gel SiO _x coating or a fluoropolymer lacquer by means of a PVD coating, for example on an industrial PVD strip coater. Furthermore, an adhesion layer which improves the adhesion of the colored layer to the metal surface and / or an adhesion layer which improves the adhesion to the sol-gel SiO _x layer or the fluoropolymer lacquer to be applied later, be applied. As a rule, further layers are absent; but this is not mandatory. The following layer systems of the following layers have proved themselves:

1st layer directly on the metal surface (optional)

Adhesive layer of Cr, Ti, Al or a nickel alloy, particularly preferably NiV, NiCr or NiAl. Particularly preferably, this layer is sputtered on.

2nd layer directly on the metal surface or directly on the adhesive layer

Layer of Si, SiO _x N _y , TiO _x N _y C _z , TiAl _s N _y O _x or CrO _x N _y C _z or ZrO _x N _y C _z , wherein x, y and z are selected such that the compounds are substoichiometric with respect to the sum of the anions and in particular with respect to the oxygen, where x> 0, while y and z are each ≥0. It is preferred if the compounds are pure oxides or oxynitrides; the presence of carbon is possible, but not mandatory. The value of s is in the range of 20 to 80 atom%, based on the existing titanium.

For this purpose, it is advantageous to sputter the layer reactive. In this case, gases are massively introduced via mass flow controllers (MFC) into the sputtering chamber in addition to the working gas (preferably argon). In addition, it is particularly advantageous to control the oxygen content defined by a lambda probe or a plasma monitor. Suitable gases are preferably oxygen, nitrogen and carbon-containing gases such as methane, ethyne or carbon dioxide.

The color can be adjusted via the layer thickness and the composition of the layers. It can z. B. shades red, orange, green, blue, purple, gold, gray or anthracite.

3rd layer of adhesive layer for the sol-gel or fluoropolymer coating (optional)

Layer of sputtered SiO _x , ZrO _x , TiO _x or ZAO (aluminum doped zinc oxide). Thickness in the range of preferably 2 - 100 nm.

A layer system with all three of these possible PVD layers is in FIG. 6 shown; see the arrow at the edge of the diagram in connection with the layers "PVD layer 1" to "PVD layer 3". The color is determined by the only existing second layer or by the synergetic interaction of all layers.

The metal plate used according to the invention generally has a thickness of 0.1 to 3 mm, but may also be thicker or thinner if required. The plate is referred to in this text in some cases as a sheet, without this being a difference to be shown. You may regularly or in a desired pattern wells or through holes contain, such as holes or slots through a Laser or punching can be introduced. This measure improves the sound absorption behavior. In order to further improve the sound absorption behavior, a sound-absorbing material (eg a fleece) can additionally be attached to the back of the ceiling element.

By patterning with an embossing roller, selectively etching the surface or by laser machining, patterns for decorative purposes can be created on the metal surface. For example, customer logos or logos can be realized. In this case, the material is preferably optionally electrochemically polished after introduction of the pattern and then either coated or anodized, only in the case of aluminum or an aluminum alloy.

In order to achieve a high energy efficiency in the forwarding of heat from or in the located on the back of the ceiling element piping system, which is traversed by a heat transfer fluid and is to be combined with the ceiling element according to the invention to form a cooling or heating blanket, the derivative should the heat from the room, which is registered by thermal infrared radiation and by thermal convection in the ceiling element, can be removed as efficiently as possible through the piping system. If, in the reverse case, the ceiling element is operated as a heating element, the heat from the pipe system must be delivered to the ceiling element as efficiently as possible.

An important parameter for the performance of a heating and cooling ceiling element is the thermal resistance value R [m ² K / kW] = F Δ T / Q ̇. This is a measure of the heat transfer between the heat carrier leading tube and the space F facing the surface of the ceiling element. It indicates which temperature difference ΔT is necessary to transport a certain amount of heat Q̇ through an area F of the surface element. The resistance R should be as small as possible. For this purpose, it is advantageous if the tubes are attached to the ceiling element, that the heat conduction between the tubes and the ceiling element is as high as possible, so that the thermal resistance is minimized.

According to the invention it is provided to attach the tubes for this purpose to the ceiling element, the joining method, however, must be designed so that when joining the surface facing the room, which must meet high aesthetic requirements is not damaged. As joining methods that ensure good heat conduction, laser welding and ultrasonic welding have proven successful in the past. Both methods, however, damage the surface facing the room. This disadvantage can be avoided if the ultrasonic welding process with the help of at least two sonotrodes as in WO 2011/128118 A1 is carried out, wherein joining strips form-fitting around the one or more laid on the back of the ceiling element (s) tube (s) and put on the back of the ceiling element to be welded. On the one hand, the space facing the space is not damaged and on the other hand, a good heat transfer achieved because under the action of ultrasound, a plastic deformation of the metal parts takes place, the surfaces of which enter into an intensive connection with each other. By using a third sonotrode as in WO 2011/128118 A1 described, with which the joining strips are welded on the side facing away from the ceiling element of the tube or pipes, the heat transfer can be even increased. This additional weld is optional.

The tubes can be made of any suitable material, such as a metal such as aluminum, an aluminum alloy, copper, a copper alloy, brass, stainless steel, plastic and a composite, wherein the composite of a plastic and a metal or of two different metals can. For the additional weld joint between joining strip and tube by means of said third sonotrode, it is advantageous, although not mandatory, if the tubes are made of metal. If they are made of metal, they should generally be metallic "bright" to achieve good heat conduction. This is especially true when it is intended that the back of the tube should be welded by means of a third sonotrode with the one or more joining strips. The thickness of the tubes and their diameter can be selected as needed. Suitable, for example, tubes with diameters of about 6-12 mm. The tubes are laid in an arbitrary pattern at a suitable, as constant as possible a distance from each other (for example 80-120 mm).

In a special embodiment with further improved heat efficiency, the tubes are pressed onto the back of the ceiling element in such a way that they deform and become flatter with increasing contact surface with the ceiling element. This measure can be carried out until the tubes have assumed an approximately semicircular cross-section, the base surface of which bears against the rear side of the ceiling element, while the rounding extends in the direction away from the ceiling element. The additional contact area gained in this way greatly improves the heat flow. For deforming the tubes, these are preferably pressed during the welding operation by means of a pressure roller.

According to the invention it is provided to make the connection between the joining strip and the back of the ceiling element particularly strong. This is achieved by the back of the metal plate of the ceiling element has no technically applied coating, but from the "bare" metal surface (ie also in the case of aluminum from the "bare" aluminum surface) as such, as it exists under natural ambient atmosphere. Aluminum forms an ambient atmosphere natural oxide skin (typically of about 10nm thickness). This means that the aluminum surface according to the invention has no anodization layer on this side.

Thus, it is ensured that in all embodiments of the invention, the back of the plate or the sheet metal remains metallic and thus well by means of the described ultrasonic welding process pipes can be welded using a joining strip.

While a "bare" surface can easily be produced or maintained with materials such as steel, tinplate or stainless steel, this "bright" surface can be achieved in the case of aluminum or an aluminum alloy by a special process after the anodization of the aluminum sheet: During the Anodization process are usually coated on both sides of the aluminum sheet with an anodization layer as described above. In order to remove the anodization layer only on the back, the surface is protected with a commercially available self-adhesive protective film (particularly preferably made of polyethylene with a rubber-based adhesive layer) and the aluminum strip is pulled through hot caustic lye. In this case, the anodization layer is etched away on the unprotected side of the aluminum strip. The strip is then rinsed in a water bath and dried. Preferably, the protective film remains on the top to the mounting of the ceiling element. This step as well as the previous anodization is preferably carried out in a conveyor system; only the finished coated or freed from the coating aluminum sheet is then cut into suitable plates, the size of which can of course vary as needed.

The natural oxide skin is easily rubbed away by the ultrasonic welding operation, so that a frictional connection between the metal surface of the metal plate and the metal surface of the joining strip is formed by the ultrasonic welding process.

In the case of aluminum or an aluminum alloy as the metal of the tile used for the ceiling element, the joining strips preferably also consist of "bare", i. non-anodized aluminum (preferably pure aluminum, e.g., A1050 or better) or an aluminum alloy. Instead, they can also be made of another metal or another metal alloy such as copper, steel or stainless steel. In the case that steel, tinplate or stainless steel is used for the ceiling element, it is advantageous that the joining strip is made of steel, tinplate or stainless steel. Copper is also excellent and also offers the advantage of higher thermal conductivity compared to steel materials.

At the back of the ceiling element fastening elements can be attached, with which the ceiling elements can be hung on the ceiling. The fasteners may be glued or more preferably by Ultrasonic welding can be attached. In this case, the fasteners are preferably made of aluminum or aluminum alloys or steel.

In a particular embodiment of the invention, the ceiling element has recesses in which bulbs are located. Favor these are introduced by laser cutting. Due to the high reflection of the material in the visible range, a high luminous efficacy or, in the case of a colored surface, a desired color impression can be achieved. In the case of LED lamps, these can be cooled particularly efficiently, so that a high light output is ensured (the luminous efficacy decreases with LEDs at the operating temperature). Of course, further components can be integrated into the ceiling element, for example loudspeaker boxes, fire sensors, sprinkler systems, etc.

The invention will be explained in more detail by means of exemplary embodiments.

A. Preparation of an aluminum sheet according to the invention

For the electrochemical treatment of the aluminum sheet, a commercially available tape anodization unit with pigmentation unit is used. Ie. Aluminum belts are treated in a continuous process in which the belt passes through different baths.

Step 1:

Caustic etching in a strong alkaline liquor to remove residues from the rolling process of aluminum (oils, fats, rolling emulsion) and the natural alumina skin of about 10nm from the aluminum surface to obtain a metallically clean surface.

Step 2:

Optional: electrochemical polishing of the surface in a mixture of phosphoric and sulfuric acid. In this case, an aluminum oxide layer is produced by applying an electrical voltage of 10 - 60V predominantly to the protruding from the surface aluminum elevations (rolling marks) by field elevation. Ie. especially the bumps are converted into aluminum oxide.

Step 3:

Etching of this aluminum oxide layer in caustic lye, so that mainly the bumps are removed.

Step 4:

Electrochemical anodising of the surface in dilute sulfuric acid under application of a voltage of 5 - 50V.

Step 5:

Optional: pigmentation. Introduction of color pigments into the pores of the aluminum oxide.

Step 6:

Sealing the pores of the alumina in hot water with chemical additives by forming aluminum hydroxide.

Step 7:

Drying, winding.

Step 8:

Apply a self-adhesive polyethylene protective film on the side that later faces the room.

Step 9:

Rerun the band anodizing unit. In this case, only the tank for etching is used to remove the anodization layer on the non-protected by the film back in hot caustic lye.

Step 10

Rinse in deionized water, dry, wind

Step 11

Aligning and cutting the aluminum strip in plates, for example in a size of 1.25 m x 2.00 m.

B. generating a heat and / or cooling ceiling element with the aluminum sheet according to A.

In the next step, 10 mm diameter copper tubes of standard thickness are placed on the back of the ceiling element and welded to aluminum horns with two sonotrodes using an ultrasonic welding machine, so that the two horns have parallel tracks. A third sonotrode welds the aluminum sheets to the back of the pipe. Possible, meandering pipe courses are in FIG. 3 shown, other, alternative pipe runs in FIG. 4 and FIG. 5 , The pipes are each about 100 mm (clear width) spaced from each other. The tube ends extend beyond the plate on one side of the plate and have suitable connection means, such as an external screw thread or a quick release. The position of the connections and the connecting elements are chosen so that several ceiling elements can be easily coupled together. Preferably flexible hoses made of plastic and / or metal are used for the connection.

The measurement of the performance of cooling ceilings is described in DIN EN 14240: The cooling ceiling element or several identical cooling ceiling elements are moved into a measuring room whose enclosure surfaces are heated to the room temperature in the test room to prevent heat loss or heat input (room temperature at test: 22. ..27 ° C) through the outer walls. In the measuring room are cooling load simulators - electrically heated radiators - which bring a defined cooling load. The room temperature T _Globe is determined with a "globe thermometer". The cooling ceiling elements are flowed through with water of defined flow and defined temperature (T _VL is the flow temperature and T _{RL is} the return temperature of the water), so that an "under temperature" T _{U is set} to room temperature.

The "under temperature" is defined by: $$\mathrm{\Delta }{T}_U=T_{\mathrm{Globe}}-\frac{T_{VL}-{\mathrm{<figure-callout\; id="2"\; label="T\; R\; L"\; filenames="imgf0002.png"\; state="\{\{state\}\}">T\; </figure-callout>}}_{RL}}{2}$$

Thereafter, a thermal equilibrium between the cooling load simulators and the cooling surface is set and the heat output of the cooling load simulators is measured. This is identical to the heat output, which is transported away by the cooling ceiling elements. If this power is normalized to the active surface of the cooling ceiling elements , the cooling capacity Q̇ is obtained .

The cooling capacity is determined at 3 different sub-temperatures and from this the power curve of the cooling ceiling element is determined: $$\dot{Q}=K\mathrm{\Delta }{T}_U^n$$

From the power curve, the nominal cooling capacity is determined at Δ T _U = 8K. The standard stipulates that a rated cooling capacity of at least 35W / m ² must be achieved for chilled ceiling elements.

The heating / cooling element produced in this way had the following technical data:

The nominal cooling capacity of the example was excellent. The thermal conduction resistance between pipes and ceiling element results from the power measurement and could be determined with less than 10m ² K / kW. This value is very favorable, since the thermal conduction resistance between the tubes and the ceiling element should be less than 50 m ² K / kW, preferably less than 20 m ² K / kW and particularly preferably 10 m ² K / kW.

Further examples of ceiling elements according to the invention have the following properties:
1) Cooling ceiling element with metallic matt surface substratum 5005 Al-Mg1 Electropolish No Roughness Ra 0.25μm ± 0.1μm Thick plate 1 mm Thick anodization 4 μm colour metallic Color values Lab Total reflection according to DIN 5036-3 75 - 79% Diffuse reflection according to DIN 5036-3 > 77% Thermal emission (100 ° C) > 73% Tube Copper 10X0,5mm Pipe axis distance 80mm tube geometry meander 2) Cooling ceiling element with aluminum-matt matt surface substratum 5005 Al-Mg1 Electropolish Yes Roughness Ra 0.20μm ± 0.1μm Thick plate 1 mm Thick anodization 4 μm colour Bright aluminum Color values Lab Total reflection according to DIN 5036-3 80 - 83% Diffuse reflection according to DIN 5036-3 > 76% Thermal emission (100 ° C) > 73% Tube Copper 10X0,75mm Pipe axis distance 100mm tube geometry meander 3) Cooling ceiling element with reflecting surface substratum Al 1090 Electropolish Yes Roughness Ra 20nm ± 10nm Thick plate 1 mm Thick anodization 3 μm colour Bright aluminum Color values Lab Total reflection according to DIN 5036-3 85 - 87% Diffuse reflection according to DIN 5036-3 <15% Thermal emission (100 ° C) > 75% Tube Copper 12X0,75mm Pipe axis distance 120mm tube geometry meander 4) Cooling ceiling element with matt golden surface substratum 5005 Al-Mg1 Electropolish Yes Roughness Ra 0.25μm ± 0.1μm Thick plate 0,5mm Thick anodization 5 μm colour gold Color values Lab L * = 81; a * = 4; b * = 40 (all values ± 2) Total reflection according to DIN 5036-3 55 - 60% Diffuse reflection according to DIN 5036-3 > 50% Thermal emission (100 ° C) 70 - 75% Tube Copper 8X0,5mm Pipe axis distance 80mm tube geometry spiral 5) Chilled ceiling element with matt dark red surface substratum 5005 Al-Mg1 Electropolish Yes Roughness Ra 0.25μm ± 0.1μm Thick plate 0,7mm Thick anodization 5 μm colour Dark red Color values Lab L * = 64; a * = 46; b * = -6 (all values ± 2) Total reflection according to DIN 5036-3 25 - 30% Diffuse reflection according to DIN 5036-3 > 20% Thermal emission (100 ° C) 65 - 70% Tube Copper 6X0.3mm Pipe axis distance 80mm tube geometry harp 6) Cooling ceiling element with a mirror-like blue surface substratum Al 1080 Electropolish Yes Roughness Ra 0,30nm ± 10nm Thick plate 0,7mm Thick anodization 6 μm colour blue Color values Lab L * = 67; a * = -24; b * = -35 (all values ± 2) Total reflection according to DIN 5036-3 35 - 40% Diffuse reflection according to DIN 5036-3 <20% Thermal emission (100 ° C) 55 - 60% Tube Copper 12X0,75mm Pipe axis distance 100mm tube geometry harp 7) Chilled ceiling element with metallic matt surface substratum stainless steel Electropolish No Roughness Ra 0.25μm ± 0.1μm Thick plate 0,4mm PVD color layer No Emission enhancing coating Sol-gel SiO _x Thick coating 3 - 4μm colour metallic dark Color values Lab Total reflection according to DIN 5036-3 Diffuse reflection according to DIN 5036-3 Thermal emission (100 ° C) > 55% Tube Stainless steel 6X0,5mm Pipe axis distance 80mm tube geometry harp 8) Chilled ceiling element with metallic matt surface substratum 5005 Al-Mg1 Electropolish No Roughness Ra 0.25μm ± 0.1μm Thick plate 1 mm Thick anodization 0μm PVD color layer No Emission enhancing coating Sol-gel SiO _x Thick coating 3 - 4μm colour metallic dark Color values Lab Total reflection according to DIN 5036-3 75 - 79% Diffuse reflection according to DIN 5036-3 > 77% Thermal emission (100 ° C) > 50% Tube Aluminum 10X1, 0mm Pipe axis distance 100mm tube geometry meander 9) Chilled ceiling element with colored matt surface substratum stainless steel Electropolish No Roughness Ra 0.25μm ± 0.1μm Thick plate 0,3mm PVD color layer NiV / CrO _x N _y / ZrO _x Emission enhancing coating Fluoropolymerlack Thick coating 6 .mu.m colour purple Color values Lab L * = 16; a * = 30; b * = -37 (all values ± 2) Total reflection according to DIN 5036-3 3-5% Diffuse reflection according to DIN 5036-3 <3% Thermal emission (100 ° C) > 55% Tube Stainless steel 6X0,5mm Pipe axis distance 80mm tube geometry harp 10) Cooling ceiling element with colored matte surface substratum 5005 Al-Mg1 Electropolish Yes Roughness Ra 0.20μm ± 0.1μm Thick aluminum plate 1.5mm Thick anodization 0μm PVD color layer NiV / CrO _x N _y / SiO _x Emission enhancing coating Sol-gel SiO _x Thick coating 3 - 4μm colour gold Color values Lab L * = 55; a * = 9; b * = 44 (all values ± 2) Total reflection according to DIN 5036-3 20 - 30% Diffuse reflection according to DIN 5036-3 <20% Thermal emission (100 ° C) > 60% Tube Aluminum 8X0,75mm Pipe axis distance 80mm tube geometry spiral

Claims (17)

Ceiling element of or with a metal plate selected from aluminum and / or aluminum alloy plates, steel, tinplate and stainless steel, the side facing the space having a layer such that the plate on this side is in the range of thermal infrared radiation (2, 0 to 50μm) a thermal emission at 100 ° C according to ISO 22975-3: 2014; Annex A.2 of at least 50%, and whose side facing away from the space is formed by the metal of the plate itself, which has no coating except for a possible natural oxide skin in the case of plates made of aluminum and / or an aluminum alloy. Ceiling element according to claim 1, whose metal plate is electropolished at least on the side facing the room. A ceiling member according to claim 1 or 2, wherein said metal plate is made of aluminum or an aluminum alloy having an anodization layer of at least 1 μm on its space-facing side. Ceiling element according to claim 3, whose anodization layer has a thickness between 1 and 10 μm, preferably between 2 and 6 μm. Ceiling element according to one of claims 3 and 4, whose anodization layer is additionally pigmented in color with inorganic and / or organic pigments. Ceiling element according to one of claims 3 to 5 with an anodization layer having a thickness between 3.5 and 10 microns, wherein the ceiling element is a thermal emission at 100 ° C according to ISO 22975-3: 2014; Annex A.2 of at least 70%. A ceiling member according to claim 1 or 2, wherein said metal plate has on its space side at least 2 μm thick transparent layer of fluorohydrocarbon chain-containing organic polymer or silicon oxide obtained by the sol-gel method as a single layer or as an outermost layer of a Layer stack, which further comprises one or more sputtered layers or consists of said layers. A ceiling element according to claim 7, wherein the layer stack comprises a colored layer of a sputtered material selected from Si, SiO _x N _y , TiO _x N _y C _z , TiAl _s N _y O _x , CrO _x N _y C _z and ZrO _x N _y C _z , wherein x, y and z are chosen such that the compounds are substoichiometric with respect to the sum of the anions and preferably also with respect to oxygen, where x> 0 and y and z are each ≥0, and s 20 to 80 Atomic%, based on the titanium. Ceiling element according to claim 8, wherein the layer stack additionally comprises either a sputtered adhesive layer which is located directly on the surface of the metal plate and is selected from the metals Cr, Ti and Al and a nickel alloy, preferably an alloy with vanadium, chromium or aluminum, and or has a sputtered adhesive layer, which is located between the colored layer of sputtered material and the at least 2 microns thick, transparent, outermost layer and is selected from stoichiometric or oxygen-substoichiometric SiO _x , TiO _x and doped with alumina zinc oxide ( ZAO). A ceiling element according to any one of the preceding claims, wherein said metal plate has a thickness between 0.1 and 3mm. Heat and / or cooling ceiling element, comprising a ceiling element according to any one of the preceding claims and at least one back mounted on this ceiling element tube, which is designed for the circulation of a heat transfer medium. A heat and / or chilled ceiling element according to claim 11, wherein the at least one tube is held in position by means of a form-fittingly placed around the back of the tube joining strip, wherein the joining strips are welded on both sides of the tube to the back of the ceiling element. Heat and / or cooling ceiling element according to claim 11 or 12, wherein the joining strips are additionally welded on the side facing away from the ceiling element of the tube at the surface thereof. Heat and / or cooling ceiling element according to one of claims 11 to 13, characterized in that the joining strip consists of a metal selected from steel, stainless steel, aluminum, an aluminum alloy, copper, a copper alloy and brass, and preferably consists of aluminum. Heat and / or cooling ceiling element according to one of claims 11 to 14, characterized in that the ceiling element facing the side of the at least one tube is flattened to form an enlarged contact surface between the tube and the ceiling element. Heat and / or cooling ceiling element according to one of claims 11 to 15, characterized in that the surface of the plate on its side facing the room pattern for decorative purposes. Heat and / or cooling ceiling element according to one of claims 11 to 16, additionally comprising light sources located in the ceiling element, in particular LED lights, fire sensors, sprinkler devices and / or loudspeaker boxes.

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