WO2010057579A2

WO2010057579A2 - Building element, building shell and building

Info

Publication number: WO2010057579A2
Application number: PCT/EP2009/007921
Authority: WO
Inventors: Jörn SCHRÖER
Original assignee: Ewald Dörken Ag
Priority date: 2008-11-19
Filing date: 2009-11-05
Publication date: 2010-05-27
Also published as: EP2356703B1; ES2433416T3; DE102009022745A1; WO2010057579A3; EP2356703A2

Abstract

The invention relates to a building element (4) of a building shell (2) comprising or forming a building outer skin (3) for a building (1), comprising a building base element to be arranged behind the building outer skin (3) and at least one thermoelectric generator (11) provided for the building base element for converting heat in particular radiative heat into electricity.

Description

Building element, building envelope and building

The present invention relates to a building element of a building shell having or forming a building envelope of a building, to be arranged with a building exterior skin behind the building shell. Furthermore, the present invention relates to a building element of a building skin of a building envelope of a building, with an outer skin element. Moreover, the invention relates to a building envelope of a building with at least one building element of the aforementioned type and a building with an aforementioned building envelope.

To distinguish, it should be noted that the two aforementioned building elements differ in that the former building element is one which is arranged as part of the building envelope behind the outer outer skin of the building. Accordingly, this building element can be, for example, a supporting structure or a part thereof, a building panel, an insulating board or an underlay or underlaying track. In contrast, the second-mentioned building element is a component of the outer building skin, such as, for example, a roofing panel or a facade panel.

The present invention is essentially concerned with the use of solar energy in the area of the building envelope of a building.

In the field of buildings, the use of solar thermal energy and of photovoltaics for the conversion of visible light into thermal energy or electrical energy is known.

Solar thermal energy is the conversion of solar energy into usable thermal energy. This is usually done by using the incident solar energy via so-called solar panels.

Photovoltaic means the direct conversion of radiant energy, mainly solar energy, into electrical energy. The energy conversion takes place with the help of solar cells, which become so-called solar modules are connected, in photovoltaic systems instead. The generated electricity can then either be used on site or fed into electricity grids.

However, the use of solar thermal and photovoltaic in the field of buildings has several disadvantages. A major disadvantage in both solar thermal and photovoltaic systems is that usually a corresponding arrangement on the building shell, often on the roof or a sunlit facade is necessary. This outside arrangement on the roof or the facade is often perceived as a visual-aesthetic impairment of the building, so that is partly ignored from a use of these facilities for this reason. In addition, it is so that the systems engineering of both systems is sometimes relatively expensive, which is associated with not inconsiderable costs, so that many users are also prevented for reasons of cost of the use of such facilities. Another major disadvantage resulting from the need for the outboard arrangement of these plants, is that the plants concerned are directly exposed to external environmental factors. Particularly in the case of storms, hail or the like, damage to the abutments or at least of parts of the plant can occur.

From the US 2005/0279400 Al already roofing elements, in particular in the form of roof tiles o. The like. Known which have on the outside of a photovoltaic cell or solar cell. The roofing elements are provided with lateral connections for electrical connection to adjacent covering plates. Such structures are very expensive and therefore costly.

DE 100 02 986 A1 discloses flat roof coverings made of light-transmitting material with photovoltaic units arranged underneath. In this case, conventional solar cells are placed under the translucent roofing to convert visible light into electricity. The problem is that special translucent roofing must be used here. Furthermore, the efficiency compared to conventional solar cells on the outside of roofing much lower. In this context, it is also problematic if the lighting permeable roofing leaves or otherwise pollute these roofing. This ultimately leads to even further efficiency reduction.

The present invention is an object of the invention to provide building elements, building envelopes and buildings, which can be done in a relatively simple and cost-effective manner power generation and / or conventional and / or provided with minor modifications building base elements or outer skin elements can be used ,

The above object is achieved in a building element of a building shell having building envelope of a building with a building exterior skin to be arranged under the building base element that the building base element is assigned at least one thermoelectric shear generator for converting heat, especially heat radiation, into electricity. This alternative of the invention thus provides for arranging at least one thermoelectric generator for converting thermal radiation into electricity on building elements which are arranged in the building envelope behind the outer skin of the building. The basic building elements may be the supporting structure or parts thereof, building panels, insulating panels or even underlayment or underlay sheets. At least one generator is attached to these, for example glued, or integrated therein. It will then be understood that the building element has corresponding connections to either connect the thermoelectric generator to other generators of the same or other building elements or to dissipate the power generated by the generator.

The thermoelectric generator is an electrothermal converter that generates a current flow based on the Seebeck effect with temperature difference. Thermoelectric generators and Peltier arrangements have long been known, p- and n-doped semiconductors whose thermal contact surfaces have different temperatures, transport electrical charges through an external circuit. These thermoelectric generators electrical work can be done on a consumer in the circuit. Peltier arrangements reverse that before However, they are identical in structure to thermoelectric generators.

At present, thermoelectric generators are used in various areas where large amounts of heat and high temperatures are generated. The advantages of thermoelectric see generators are in their high reliability. They work independently of atmospheric conditions such as humidity. There is no fault-susceptible mass transport, but only a charge transport.

The materials used for thermoelectric generators are usually evaluated on the basis of the figure of merit ZT, which depends on the Seebeck coefficient, the electrical conductivity, the thermal conductivity and the temperature. The materials contained in the figure of merit depend above all on the charge carrier concentration of the respective material, with narrow bandgap semiconductors achieving the highest ZT values in the range of room temperature. Therefore, also in connection with the present invention corresponding semiconductor materials with a narrow band gap are to be preferred. Increasing the thermoelectric figure of merit is always to be understood as an optimization of the entire parameter set and can not be achieved by maximizing or minimizing only one of the variables contained.

The currently commercially available thermoelectric components achieve figures of goodness in the range of about ZT = 1. By using nanostructured materials, ZT values between 1 and 3 can be achieved.

Good ZT values are generally achieved when the thermoelectric material used in the thermoelectric generator has a mixed oxide containing the elements titanium, oxygen, sulfur and Me with Me = calcium, strontium and / or barium. As a result, efficiencies between 3 to 5% are possible. The same efficiencies arise when using semiconductor materials of Bi ₂ Te ₃ , PbTe, Si, Ge, BiSb or FeSi ₂ .

In order to achieve a high thermoelectric efficiency, it is provided in a preferred embodiment that the generator is mounted on the bäudeaußenhaut facing the outside of the building base element is arranged. The generator thus has in the installed state with its heat radiation receiving contact side in the direction of the building outer skin and is preferably only slightly spaced from the building outer skin to accommodate a large amount of heat radiation can.

Unlike the internal building element according to the invention, it is in the outer building element, which is for example a roofing plate or a facade panel, so that the thermoelectric generator is disposed on the inside of the outer skin member. The generator then absorbs the heat directly, in particular by heat conduction of the outer skin element.

In both alternatives according to the invention, however, it is in each case so that the thermoelectric generator or the arrangement for generating the electric current is not on the outside of the outer skin of the building envelope of the building, so that the visual aesthetic impression of the building is not affected and the Arrangement, moreover, not the environmental influences and thus the risk of damage in storms, hail o. The like. Is exposed.

In a preferred embodiment of the invention, generators are provided both on the building elements of the outer building skin and on the inner building elements. In this way can be easily achieved an increase in the number of thermoelectric generators per unit area.

In particular, when the thermoelectric generators are provided for use in conjunction with underlays or underlay webs, it makes sense to form the generators flexible or foil-like. In this way, the function and handling of the respective tracks is not affected by the generators provided on the upper side of the tracks.

Moreover, it goes without saying that it is easily possible to use the thermoelectric generators provided in the invention on the building elements by the use of photovoltaic and / or solar thermal energy. To supplement funds. In this case, the photovoltaic and / or solar thermal means preferably inside, ie behind the building outer skin, be provided in order not to affect the possible by the thermoelectric generators possible effect of concealed arrangement of the power generation arrangement according to the invention. Prerequisite for the use of additional photovoltaic and / or solar thermal means is then that the outer building skin is either at least partially open, so that direct sunlight is possible, or that the building outer skin at least partially transparent outer skin elements, so for example transparent facade and / or roofing elements comprises, behind which then the respective means are arranged.

With regard to the temperatures occurring in the region of the outer skin of the building, the thermoelectric generator, in particular as regards the material selection of the semiconductor materials, designed such that the generator for the conversion of infrared radiation in the wavelength range between 2 to 20 microns, preferably between 6 and 13 μm is formed and optimized. This means that the absorption maximum lies in the aforementioned interval. It is understood that each individual value within the aforementioned range limits is possible. Preferably, the absorption maximum is at a wavelength between 8 and 10 microns.

To increase the efficiency of the building shell of the building envelope according to the invention is provided in the outer skin of the building that at least one outer Gebäudeele- element or an outer skin element is provided on the outside at least partially with a coating to increase the heating. The abovementioned coating is an absorber layer which preferably has a high degree of absorption (low reflection) in the visible light range and / or low emission (high reflection) in the heat radiation range. Preferably, the coating should have a high visible light absorption of more than 80%, preferably more than 90%, and more preferably between 92 and 98%. The emission in the area of thermal radiation should be between 2 and 10% and in particular between 3 and 7%. For example, with a 95% absorption of visible light and a 5% emission in the rich heat radiation about 90% of the incident solar energy can be converted into usable heat.

Preferably, the aforementioned coating is composed of several functional layers. The carrier material may be a metal substrate with good reflection and heat conduction. The carrier material is then applied to the outside of the relevant building element or can form this. Furthermore, a thin titanium carbide compound or other compound can serve as an adhesion-promoting layer and diffusion barrier. On the carrier material or the optional adhesion-promoting layer, the absorber layer is provided as the actual functional layer. This preferably consists of a titanium compound with oxygen and nitrogen. Preference is given here TiN, TiO and TiO ₂ are used. Finally, an antireflection and / or protective layer can be located on the absorber layer, which can basically consist of a quartz glass, but also of a plastic material. By minimizing surface reflection, the absorption of solar radiation is further optimized.

It is understood that it is sufficient in the context of the present invention to provide only the absorber layer on the outer skin member, wherein the outer skin member itself can serve as a carrier. For a better connection between the absorber layer and the outer skin element, the adhesion-promoting layer and / or the protective layer on the outside can additionally be provided.

The abovementioned coating is therefore of considerable importance since, according to Stefan-Boltzmann's law, the emitted radiation energy is proportional to the fourth power of the temperature. The higher the temperature, the higher the energy gain.

Incidentally, in connection with the building envelope according to the invention, it may be appropriate to assign a cooling device to the building element on the inside. Ultimately, it is important to cool the lower-temperature contact surface of the generator in order to achieve the largest possible temperature difference between the generator surfaces, so that ultimately results in a correspondingly high current. Moreover, it is advantageous that the thermoelectric generator having building element in predominantly sunlit areas of the building envelope, ie in particular in areas that are aligned to the east, south and / or west, is provided. Particularly preferred is the use of building elements according to the invention in the areas of the building with a south, southwest or southeast orientation.

Incidentally, in connection with the building according to the invention, it is provided that the generator is coupled to at least one consumer in the building. Since the generator generates a DC current with comparatively small voltages, it makes sense that the generator is coupled to an accumulator as an energy store and / or to an inverter, so that the generated current is not only used by an AC consumer on site but can also be fed into the public grid. The energy storage ultimately serves as a buffer to continuously provide energy available.

Finally, the present invention relates to the use of thermoelectric generators for converting heat, in particular heat radiation, into electricity in the vicinity of buildings, the generators being arranged under or behind an external building skin of a building and heat emitted and / or transmitted by the building exterior skin, in particular infrared radiation, convert into electricity.

Further aspects, advantages, characteristics and features of the present invention will become apparent from the claims and the following description of a preferred embodiment with reference to the drawing. It shows

1 is a schematic representation of a building with a building envelope,

2 shows a schematic representation of a part of a building envelope,

Fig. 3 is a schematic representation of a building element according to the invention and Fig. 4 is a schematic representation of a thermoelectric generator for use in a building element.

In Fig. 1, a building 1 is shown schematically. The building 1 has a building envelope 2 which is bounded on the outside by a building skin 3 or forms this. Both the building envelope 2 and the building outer skin 3 have building elements 4, 5, wherein the building elements 4 of the building shell 2 are arranged behind the building outer skin 3, while the building elements 5 are arranged outside as part of the building outer skin 3. Thus, the outer sides of the building elements 5 form the outside of the building outer skin. 3

In the illustrated embodiment, the building envelope 2 of the building 1 has a facade 6 and a roof 7. Both the facade 6 and the roof 7 have individual building elements 4, 5, which will be discussed in more detail below.

In Fig. 2, a part of the building envelope 3 is shown. In detail, it is about a part of the roof 7. The building envelope 2 in the present case has a building outer skin 3, a plurality of outer building elements 5, which ultimately form outer skin elements. Unlike the embodiment of FIG. 3 to be described, the outer building elements 5 and the outer skin elements in the embodiment according to FIG. 2 are identical. This is in the illustrated embodiment to known roofing elements. Under or behind the outer building skin 3, ie in the direction of the building interior, interior building elements 4 are provided as parts of the building envelope 2. In the case of the individual building elements 4, which, insofar as they do not represent a modification in the direction of the present invention, correspond to known building foundations, the present invention is a support battens 8 onto which the roof covering elements are laid, as well as a underlay web 9 arranged underneath the support battens 8 is.

It should be noted that in Fig. 2, only an exemplary embodiment is shown. It is understood that the building envelope 2 is not necessary must necessarily have a sarking 9. In addition, what is not shown here, also insulation panels or other structural panels may be part of the building envelope. The aforementioned components then also represent building elements 4 or building basic elements in the sense of the present invention.

The above statements regarding the building elements 4, 5 apply, moreover, also for the part of the facade. In this case, the outer skin of the building is then formed by outer facade panels as outer building elements or outer skin elements, while the elements arranged behind the facade panels form the inner building elements or basic building elements.

In the embodiment shown in FIG. 2, it is now the case that a plurality of thermoelectric generators 11 is provided on the outer or upper side 10 of building elements 4, in this case the underlay strip 9. In principle, it is also possible, instead of a large number of smaller generators 11, to provide a smaller number of larger generators 11 from the surface. A preferred construction of the thermoelectric generators 11 will be discussed later with reference to FIG. 4. In the present case, the thermoelectric generators 11 are used for the conversion of thermal radiation 12, which results from the solar irradiation of the building shell 3 or is discharged from the outer shell 3 forming building elements 5, in electricity.

It should be pointed out that instead of on the top 10 of the underlay 9 thermoelectric generators on the building elements 5 facing upper sides of the roof battens 8 could be provided. Incidentally, in the case of non-realization of the underlay sheet 9, the generators 11 could also be provided on further interior building elements 4.

In the illustrated embodiment, the generators 11 are preferably glued to the top 10 of the underlay 9. It is not shown that the individual generators 11 are preferably electrically connected to a rechargeable battery and / or converter (not shown). It is to be noted, moreover, that the generators 11 may in principle also be laminated into the underlay strip 9 or fastened in another way to the underlay strip 9 or be integrated into it. In addition, what is also not shown, the underlay sheet 9 may be formed heat or infrared radiation reflective, so that the majority of the heat radiation passes to the generators 11. The distance of the upper side 13 of the generators 11 to the heat radiation 12 emitted underside of the building elements 5 should be only a few centimeters, preferably less than 5 cm.

In Fig. 3, a roof tile is shown as an outer building element 5. The building element 5 has an outer skin element 14 as the base body. It is such that on the inner or underside 15 of the outer skin member 14, a thermoelectric generator 11 is provided. This generator 11 converts the heat energy transferred by heat conduction through the skin member 14 into electric power. In addition, the building element 5 preferably has an absorption layer or coating 16 on its outside. The coating 16, which may consist of a titanium oxinitrite compound, for example, has a solar absorptance of 90% ± 8% and / or a thermal emissivity of 10% ± 8%. Ultimately, the absorption layer ensures that only a small portion of the solar radiation reflects and only a small part of the heat radiation is emitted to the outside. The majority of the solar energy is released in the form of heat in the direction of the thermoelectric generators 11.

It is understood that the coating 16 in principle not only in combination with thermoelectric generators 11 must be provided on the building elements 5. Thus, it is readily possible, even on the outside of the building elements 5 to provide the coating 16, without that generators 11 must be provided on the underside. Also, the generators 11 may be provided without the coating is provided.

It should be pointed out, moreover, that the building elements 4, 5 can form prefabricated building units with the generators 11, which can then be assembled as a complete structural unit at the building site together with the building concerned. be laid foundation element. In this case, then only an electrical connection of the individual generators 11 and the electrical connection is required. But it is also possible to attach to per se known outer skin elements or building base elements, the respective generators 11 only on the site. So it is possible, for example, after installation of the underlay sheet 9 on the top 10 of the underlay sheet 9, the generators 11 apply and connect them electrically afterwards. The application could then be done in a simple manner by previously mentioned bonding. The same applies to the underside arrangement of the generators 11 on the underside of the roof tiles.

It is not shown, moreover, that below the generators 11, ie in the direction of the building interior, a cooling or heat sink can be provided. The effect of cooling will be discussed in more detail below in connection with FIG. 4.

In Fig. 4, a preferred construction of a thermoelectric see generator 11 is shown schematically. The generator 11 consists of at least two, in the present case of eight cuboids 17, 18 of p- and n-doped semiconductor material, which are alternately connected at the top and bottom by metal bridges 19. The metal bridges 19 at the same time form the thermal contact surfaces and are insulated by an upper-side plate 20 and a lower-side plate 21. The arrangement of the cuboids 17, 18 is such that p-doped cubes 17 and n-doped cuboids 18 are successively electrically connected to each other so that they are connected in series. By establishing a temperature difference between the plates 20, 21 and the contact surfaces, an electric current is generated. The larger the temperature difference, the greater the generated current. If, for example, the contact surface associated with the plate 21 is provided with its upper side for receiving the heat or thermal radiation, while the contact surface facing the lower plate 21 faces the interior of the building and has a lower temperature, this results in an electric current. If the temperature acting on the plate 20 is increased, for example by using the aforementioned coating on plate 20 or building element 5 and, moreover, the plate 21 is cooled on the underside, there is an increased temperature difference and thus a larger current. In this context, it can be offered, the Form plate 21 as a heat sink. Conveniently, the underlay 9 could be designed to be good heat conducting for cooling.

In the illustrated embodiment according to FIG. 4, the generator 11 is in the horizontal installed position. Ultimately, the position of the generator 11 and the plates 20, 21 of the position of the relevant building element 4, 5 adapted in the installed position. In a Dachanordung the generator 11 is therefore arranged obliquely, while it is arranged for example in a facade assembly in a vertical position, so that the plates 20, 21 are arranged vertically.

LIST OF REFERENCE NUMBERS

1 building

2 building shell

3 building outer skin

4 building part

5 part of the building

6 facade

7 roof

8 battens

9 underlay membrane

10 top

11 generator

12 heat radiation

13 top

14 outer skin element

15 bottom

16 coating

17 cuboid

18 cuboid

19 bridge 0 plate 1 plate

Claims

Claims:

1. Building element (4) of a building outer skin (3) having or forming building envelope (2) of a building (1), with a building exterior skin behind the building outer skin (3) to be arranged building base element and at least one of the building base element associated thermoelectric generator (11) for conversion of heat, especially heat radiation, into electricity.

2. Building element according to claim 1, characterized in that the generator (11) on a supporting construction means, a building plate, a

Insulating board or an underlay or underlay (9) is provided as a building base element.

3. Building element according to claim 1 or 2, characterized in that the generator (11) is arranged on the outer skin of the building (3) facing the outside of the building base element.

4. building element (5) of an outer building skin (3) of a building envelope (2) of a building (1), with an outer skin element (14) and at least one outer skin element (14) associated thermoelectric generator (1 1) for the conversion of heat into electricity, wherein the generator (11) on the inside of the outer skin member (14) is provided or integrated in this.

5. Building element according to claim 4, characterized in that the generator (11) is provided on a roofing plate or a facade panel as an outer skin element (14).

6. Building element according to claim 4 or 5, characterized in that the outer skin element (14) is provided on the outside at least partially with a coating (16) to increase the heating.

7. Building element according to one of the preceding claims, characterized in that the generator (11) fixedly connected to the building base element or the outer skin element (14), in particular glued, or is integrated therein.

8. Building element according to one of the preceding claims, characterized in that the generator (11) is designed to be flexible or film-like.

9. Building element according to one of the preceding claims, characterized in that the generator (11) for the conversion of infrared radiation, in particular with a wavelength in the range between 2 and 20 microns, preferably formed between 7 and 13 microns and in particular between 8 and 10 microns and is optimized.

10. Building element according to one of the preceding claims, characterized in that in addition at least one photovoltaic and / or solar larthermie means is provided.

11. Building envelope (2) of a building (1) with at least one building element (4, 5) according to one of the preceding claims and an outer building skin (3), wherein the building element (4, 5) at least one thermoelectric see generator (11 ) for converting, in particular heat radiation, into electricity.

12. Building envelope according to claim 11, characterized in that the generator (11) is assigned inside a cooling device.

13. Building envelope according to claim 11 or 12, characterized in that the building element (4, 5) in predominantly sunlit areas of

Building envelope (2), in particular in east, south and / or west aligned areas of the building envelope (2) is provided.

14. Building envelope according to one of claims 11 to 13, characterized in that the building outer skin (3) has at least one transparent outer skin element (14).

15. Building envelope according to one of claims 11 to 14, characterized in that the building outer skin (3) on the outside at least partially with a coating (16) is provided to increase the heating.

16. Building (1) with a building envelope (2) according to one of claims 11 to 15.

17. Building according to claim 16, characterized in that the generator (11) with at least one consumer in the building (1) is coupled.

18. Building according to claim 16 or 17, characterized in that the generator (11) is coupled to an inverter and that, preferably, the power generated is fed into the public grid.

19. Building according to one of claims 16 to 18, characterized in that the generator (11) is coupled to an accumulator as energy storage.

20. Use of thermoelectric see generators (11) for the conversion of heat, in particular heat radiation in electricity in the building envelope (2) of a building (1), wherein the generators (11) under or behind the building outer skin (3) of the building envelope (2 ) of the building (1) are arranged and convert the heat emitted by the building exterior skin (3) and / or transmitted heat, in particular infrared radiation, into electricity.