WO1999042766A1

WO1999042766A1 - Device for absorbing solar energy on buildings

Info

Publication number: WO1999042766A1
Application number: PCT/DE1999/000401
Authority: WO
Inventors: Christian Henkes; Ferdinand Henkes
Original assignee: Henkes Christian Hm
Priority date: 1998-02-17
Filing date: 1999-02-12
Publication date: 1999-08-26
Also published as: DE19980273D2; AU2921499A; DE19806533A1

Abstract

A device for absorbing energy which acts upon regions of the outer skin (10, 82) of a building in the form of radiation and/or heat energy from the outer surroundings of the building, comprises a layer of heat-insulating material (20, 70) arranged under selected outer skin regions (10; 82) in such a way that air convection ducts (41, 42) are formed between this layer (20, 70) and the outer skin regions (10, 82), as well as an air conveyor (45) for conveying air from the air convection ducts (41, 42) to an available heat sink (50). An air-permeable dry absorber (30) with high radiation-absorption capacity and heat conductivity is arranged inside the air convection ducts (41, 42) in a substantially parallel direction to the outer skin (10; 82) and extends parallel to the outer skin (10; 82) over the length and width of the air convection ducts (41, 42). Air flows through the dry absorber (30) and is then conveyed by the air conveyor (45) to the available heat sink (50).

Description

Arrangement for absorbing solar energy on buildings

description

The invention relates to an arrangement for absorbing energy which acts as radiation and / or thermal energy from the external environment of a building on areas of the outer skin of the building, with a layer of heat-insulating material which is arranged under selected outer skin areas, between this layer and the outer skin areas are formed air convection channels, and with an air transfer device for transferring air from the air convection channels to a useful heat sink.

Arrangements for absorbing solar energy on buildings are widely known. Currently, the most common are solar panels in the form of flat components, which are installed on a side of the roof facing the sun and have the shape of flat housings with a radiation-permeable surface and an interior covered with a tube system, which is heated up by solar radiation similar to a greenhouse and which transfers heat thus collected to a liquid flowing in the tubes. The liquid is then fed to a useful heat sink, for example the evaporator side of a heat pump or directly to a heat exchanger for hot water preparation, in order to use it in the household of the building as process water or for heating purposes. Such solar panels are sensitive to mechanical influences and dirt, they also impair the appearance of the roof, require relatively complex installation work and require frequent maintenance. These problems are avoided by a roof known from DE-A-28 09 442, in which the roof covering has gaps arranged between a sealing covering and a heat insulation layer, in which air circulation between a first opening pointing into the interior of the building and one outside the building pointing second opening takes place. The air that warms up in the spaces as a result of solar radiation on the outer skin can be used to heat the building, which of course only makes sense in colder seasons. In summer, the air from the inside of the house is passed through the gaps to the outside, in order to prevent the solar radiation on the roof skin from being transferred to the inside of the house by a heat exchange. In the summer, the heat is lost so unused.

In view of this disadvantage, it is suggested in EP-A-0 033 145 to provide an air collection space in a roof for a solar-heated house for heating air by means of heat absorption from the solar energy radiated onto the roof. The air-collecting space, which is arranged under the roof ridge and allows light radiation to pass inwards, contains special tube collectors with a closed fluid circulation system and is also connected to the interior of the house via supply and exhaust air ducts. An air insulation cushion is created in the supply air ducts to the air collection space running under the roof skin, which is set into motion by convection when exposed to sunlight, so that an air exchange can occur between these ducts and the air collection space. The liquid heated in the tube collectors is used to operate a heat exchanger that is directly connected to the water circuit in the house.

This solar system also requires extensive intervention in the construction of the roof. This applies both to setting up the air collection space and the pipe collectors located in it. under the roof ridge as well as the formation of the roof covering at this location, where separate, transparent molded panels have to be arranged instead of the roofing otherwise used.

The object of the present invention is to take advantage of the radiation and / or thermal energy acting on the outer skin of the building from the external environment of a building by means of an arrangement which has little effect on the external appearance of the building, is easy to install and yet has one ensures a satisfactory level of utilization of the external energy.

This object is achieved by the invention in an arrangement with the features of claim 1. Advantageous refinements and developments of the arrangement according to the invention are the subject of the dependent claims.

An arrangement according to the invention for absorbing energy which acts as radiation and / or thermal energy from the external environment of a building on areas of the outer skin of the building contains a layer of heat-insulating material which is arranged under selected outer skin areas, between this layer and the Air convection channels are formed in the outer skin areas, and an air transfer device for transferring air from the air convection channels to a useful heat sink. An air-permeable dry absorber with high radiation absorption capacity and high thermal conductivity is arranged within the air convection channels and extends essentially parallel to the outer skin over the length and width of the air convection channels. The air transfer device directs the air that has flowed through the dry absorber to the useful heat sink. The arrangement according to the invention can be installed both on areas of the lateral outer skin (that is on side walls) and under the roof skin and achieves a useful effect even when using conventional building materials for these outer skin areas. It is of course particularly advantageous to give the relevant outer skin areas good radiation absorption capacity, so that the smallest possible part of the incident radiation energy is lost by reflection. But even in the case of less good radiation-absorbing outer skin areas, a useful effect can be achieved by the material contact of the outer skin with warm ambient air.

If the arrangement according to the invention is installed under the roof skin, conventional coverings such as clay or concrete tiles, natural or synthetic slate, corrugated sheets made of hard fiber cement or hard fiber bitumen or steel sheet, galvanized trapezoidal sheets or copper sheets bring a satisfactory effect if they are laid directly on the roof battens. The relevant outer skin areas, in particular when it is brick, are preferably provided with a selective coating.

The arrangement according to the invention does not require tube collectors with a liquid circuit and does not require any transparent plates, as are used in conventional solar collectors to achieve the greenhouse effect. The possibility created by the invention of using or maintaining conventional outer skin elements or materials is advantageous for both aesthetic and economic reasons. A possible fear of a reduction in efficiency due to the elimination of the greenhouse effect is counteracted in the arrangement according to the invention by a plurality of other utilization factors if it is not even more than compensated for. Firstly, larger areas of the outer skin can be used, even those in which, for architectural reasons, conventional solar panels cannot be arranged. Second, the lack of radiation transparency of normal skin materials is offset by the exploitation of the heat absorption and heat storage capabilities of such materials. Not only is the radiation energy from sunlight absorbed, but also the thermal energy from the ambient air flowing through the outer skin, which is not the case with conventional solar collectors. In this way, any warming of the outer skin can be derived, for example, even during the night during summer, when the outer skin is still at a higher temperature due to the storage of the daytime heat or may be warmed by mild night air. A third factor is the presence of the dry absorber according to the invention, which on the one hand ensures a high efficiency of heat transfer from the heated outer skin areas to the useful heat sink due to its radiation-absorbing effect and on the other hand through its thermal conductivity. The dry absorber preferably consists of a black matt lacquered or anodized metal knitted fabric, for example of aluminum. Dry absorbers made of knitted metal are known per se from WO 94/19652, specifically for absorbing direct sunlight.

It is particularly advantageous if, in an advantageous embodiment of the invention, the dry absorber is arranged at a distance from both the outer skin and the heat-insulating layer in order to divide the air convection channels into a primary flow chamber facing the outer skin and a secondary flow chamber facing the heat-insulating layer, whereby the air transfer device directs air from the secondary flow chamber to the useful heat sink. The heat-insulating layer is preferably provided on its inner surface delimiting the air convection channels with a warmer reflective covering.

Hollow stones can be used for the formation of the air convection channels, the inlet air inlet of which is located at the lower end and the outlet air outlet of which is located at the upper end. It is then advantageous to arrange the supply air ducts in each case between these hollow blocks, whereby hollow blocks are also expediently used for the formation of the supply air ducts.

Heat consumers or heat stores of any kind can be used as the useful heat sink. During the daytime or when room heating is not required, the air from the air convection channels of the arrangement according to the invention can be fed to a heat exchanger and / or a heat store, for example for hot water preparation, if desired via a heat pump.

For the operation of heat exchangers or for charging heat stores, the air heated with the arrangement according to the invention is preferably conducted in a closed circuit, i.e. the exhaust air outlet of the useful heat sink is connected to a supply air inlet of the air convection channels, while the exhaust air outlet of the convection channels leads to the supply air inlet of the useful heat sink, this circuit preferably being driven by a blower.

The arrangement according to the invention is particularly suitable for charging a long-term heat store, which can be, for example, a liquid tank sunk into the ground. In this case, the air heated in the air convection channels of the arrangement according to the invention can be given to the primary side of a heat exchanger, the secondary side of which is flowed through by the storage liquid of the tank. In this way, the radiation or heat energy, which acts on the building during the entire warm season, can be accumulated in the long-term heat accumulator, and then during the to be used in the building during the cold season for heating purposes, if necessary with the interposition of a heat pump.

This type of application takes into account the peculiarities of the arrangement according to the invention particularly well, since this arrangement develops the best efficiency if it works in long-term operation throughout the warm season. This is because, in the arrangement according to the invention, the heat capacity and also the storage capacity of the building materials of the outer skin are also determinative and this results in an inertia which, as it were, smoothes the effects of the fluctuations in solar energy on the thermal output of the arrangement. Thus the degree of exploitation of this heat output will also be highest if the heat sink, that is to say the consumer of the heat output, absorbs the offered heat output as steadily as possible and without surge operation. This condition is perfectly fulfilled with the long-term storage.

Further details of the invention as well as advantageous refinements and special advantages are explained in more detail below using an exemplary embodiment with reference to the drawing. Show it :

Fig. 1 is a schematic representation of an arrangement according to the invention;

Fig. 2 shows a vertical section through an area of a

House roof, which is provided with an arrangement according to the invention;

3A to 3C

Details of the installation of the arrangement according to the invention between the rafters of the roof shown in Fig. 2; Fig. 4 shows a part of a perspective view

Expanded mesh, as can be used for the construction of the dry absorber contained in the arrangement according to the invention; and

5A to 5C

Details of the construction of a side wall of a building for realizing the invention.

1 shows a section of an area of the outer skin 10 of a building, on which radiation and / or thermal energy from the environment acts, as indicated by the sun symbol and the bundle of arrows. The outer skin 10 can e.g. be the roof covering of the building, for example in the form of bricks, which are laid directly on roof battens. Under the outer skin 10 there is a dam layer 20 made of heat-insulating material. The dam layer 20 is arranged in such a way that space for air flow remains between it and the outer skin 10. An air-permeable dry absorber 30 with a high radiation absorption capacity and high thermal conductivity extends essentially parallel to the outer skin 10. The dry absorber 30 divides the air space into a primary flow chamber 41 facing the outer skin 10 and a secondary flow chamber 42 facing the dam layer 20. The primary flow chamber 41 is connected to an air inlet 43, which is preferably arranged at a spatially lower end. The secondary flow chamber 42 is connected to an air outlet 44, preferably at a higher end.

The air outlet 44 leads to a blower 45 and from there to the air inlet of an air / water heat exchanger 50. The air outlet of the heat exchanger 50 is in turn connected to the air inlet 43 of the primary flow chamber 41. The solar radiation and / or ambient heat acting on the outer skin 10 leads to the heating of the outer skin. The heat of the outer skin 10 is transmitted by material contact to the air flowing in the primary flow chamber 41 and by radiation to the dry absorber 30, which then additionally heats the air flowing through the skin. The air heat is transferred in the heat exchanger 50 to a water circuit, which can be switched via feed and return lines 61 and 62, associated control valves 63 and 64 for charging a heat storage device 66, driven by a pump 65. The heat storage device 66, for example an im Soil-buried water storage, can be connected together with the pump 65 via the valves 63 and 64 alternatively to the evaporator side of a heat pump 65 in order to use the thermal energy stored in it to operate a room heating H, for example during the cold season.

The arrangement shown in FIG. 1 can be switched into operation for charging the heat storage device 66 as soon as and as long as the temperature of the supply air at the heat exchanger 50 is higher than the water temperature m of the return line at the heat exchanger. This condition can be monitored by a temperature sensor system on the heat exchanger. Alternatively, the charging mode can also be switched on and off in response to external air temperature sensors, voltaic solar cells or external skin temperature sensors.

2 and 3A to 3C show details of an example for the installation of an arrangement according to the invention under the roof skin of a house. In the case shown, the roof skin consists of bricks 10 which are laid directly on the roof battens 11. The bricks 10 are conventional clay or concrete bricks of any known shape. The roof battens 11 are nailed onto the rafters 12, as can be seen in FIGS. 3A and 3C, which show a section perpendicular to the drawing. 10

plane of Fig. 2 show. Individual, essentially similar modules are fitted into the spaces between adjacent rafters 12, one of which is shown in perspective and in section in FIG. 3B. Each module has a sheet of rigid plastic foam forming the dam layer 20, e.g. Polyurethane foam, the width of which corresponds to the space between the rafters 12 and which has on its upper side a plurality of spaced-apart, longitudinally extending central webs 21 and two outer webs 22 lying on the edge. The outer webs 22 are higher than the central webs 21 and each have a shoulder on their inside at a height that corresponds to the height of the central webs 21. The middle webs 21 and the shoulders of the outer webs 22 form the support for the dry absorber 30, which is a knitted metal fabric, consisting of several superimposed and matt black lacquered aluminum expanded grids. The upper ends of the edge webs 22 protrude above the top of the dry absorber 30. A support plate 23 made of gypsum or hard fiber is located on the underside of the dam layer plate 20.

3B is equal to the thickness of the rafters 12, so that after the module has been inserted between the rafters 12, the upper edge of the side webs 22 abutting the roof battens 11, the underside of the support plate 23 is flush with the underside the rafters is 12. This creates a smooth, continuous ceiling in the attic. The height of the center webs 21 and the shoulders on the side webs 22 and the total height of these side webs 22 are dimensioned such that both on the side of the dry absorber 30 facing the roof skin 10 and on the side facing the dam layer plate 20, respectively, sufficiently large air channels 41 and 42 for sufficient convection remain, as can be seen in FIG. 3C, which shows the module according to FIG. 3B in the installed state. 11

The modules according to FIG. 3B can be produced as ready-to-build elements and can be installed in existing roof structures with little effort, so that the arrangement according to the invention can also be used for old buildings. A new roofing is not necessary. The top side of the insulation layer panel 20 and also its middle and side webs 21 and 22 are preferably laminated with aluminum foil in order to improve the heat reflection to the dry absorber 30 and thus to increase the efficiency of the entire arrangement. In addition to the main objective of absorbing ambient heat, the arrangement also insulates the roof against heat loss to the outside in winter.

As already mentioned, the dry absorber 30 can be a knitted metal fabric made of a plurality of black-lacquered aluminum expanded metal meshes lying one above the other. Preferably at least seven layers of long web expanded metal are used, for a total thickness of the dry absorber of at least 16 mm and a maximum of 20 mm and for an inner surface of 3.6 to 4 m ² / m ² . Seven expanded metal layers with the following dimensions can be used for this:

a) Top layer made of long web expanded mesh, mesh length 20 mm

Knot length 4 mm

Knot width 4 mm

Bridge width 2 mm

Web thickness 0.2 mm

b) two layers with the same data as a), but web thickness 0.1 mm 12

c) three layers of long web expanded metal mesh 12 mm long

Knot length 2 mm

Knot width 2 mm

Bridge width 1 mm

Bridge thickness 0.1 mm

d) End position of long-wall expanded metal with the same data as c), but web thickness 0.2 mm

The meaning of the individual terms "mesh length", "knot length", "knot width", "web width" and "web thickness" results from Fig. 4, where a is the mesh length, b the knot length, c the knot width, d the web width, e the Bridge thickness and S shows the flow. The dimension "long" goes in the direction of the air flow, while the dimensions "width" and "thickness" are directed in a plane perpendicular thereto.

Instead of the bricks mentioned and shown in FIGS. 2, 3A and 3C, the outer skin 10 can also have natural or artificial slate elements, each laid on a slatted frame. Alternatively, the outer skin can also be formed by corrugated sheets made of mineral fiber cement or steel sheet or hard fiber bitumen. Galvanized and matt lacquered trapezoidal sheet or black-oxidized copper sheet can also be used. These are only examples of preferred configurations of the outer skin, wherein the outer skin areas to be equipped with the arrangement according to the invention can lie not only on the roof but also on the side walls of the building.

5A to 50 show details of an example of the application of the invention to the side wall of a building. In the case shown, the supporting structure of the side wall is a masonry 70 made of heat-insulating bricks 71, as can be seen most clearly in FIG. 5A, which is a horizontal section through the perspective view in FIG. 13

5B shows illustrated sidewall. The masonry 70 also forms the dam layer of the arrangement according to the invention. The bricks 71 are preferably so-called "Poroton" tiles, consisting of porous clay, the porosity of which is achieved by adding hard foam particles before firing.

On the outward-facing side of the heat-insulating masonry 70 there is a layer of hollow bricks 80 of the first type and hollow bricks 90 of the second type. The hollow bricks preferably consist of fired clay (hollow brick systems). The cavities in the hollow bricks 80 of the first type are each delimited by a rear wall 81 leaning against the masonry 70, a front wall 82 running at a distance and parallel to it and two side walls 83 and 84. The front walls 82 of the hollow bricks 80 form the outer skin, to which the radiation and / or thermal energy acts from the external environment of the building.

The cavities in the hollow stones 80 form air convection channels which are divided into the primary flow chamber 41 and the secondary flow chamber 42 by the dry absorbers 30. The dry absorbers 30 can be designed as described above in connection with FIGS. 3A to 30 and 4. The dry absorbers 30 are each held on their side edges by a groove which is formed between a pair of elongated projections m in each side wall 83 and 84 of the hollow blocks 80. Parts of the inner surface of the hollow blocks 80, at least the inner surface of the rear wall 82, are preferably aluminum-clad in order to improve heat reflection to the dry absorber.

The hollow blocks 90 of the second type form supply air channels 95 for the primary flow chambers 41 in the hollow blocks 80. The hollow blocks 90 are preferably made of the same material and have the same thickness as the hollow blocks 80 and are arranged laterally next to the latter, in such a way that they are - 14

tenwandung of each hollow block 80 abuts a side wall of a hollow block 90. Each supply air duct 95 is connected near its lower end via side air passages 43 to the primary flow chamber 41 of the respectively adjacent hollow blocks 80, as shown in dashed lines in the perspective view of FIG. 5B and in the vertical sectional view of FIG. 50, which is a section along line CC 5A, is indicated. The hollow blocks 90 are kept relatively narrow, preferably less than 1/3 of the width of the hollow blocks 80. In the direction orthogonal to the level of the masonry 70, the hollow blocks 80 and 90 preferably have the same dimensions.

In operation, the cold air to be heated is introduced at the top of the supply air ducts 95, in order to then flow at its lower ends through the side passages 43 into the primary flow chambers 41, where it flows through the dry absorbers 30 under heating and at the upper end of the hollow blocks 80 is withdrawn from the secondary flow chambers 42 in order to arrive at the useful heat sink, for example to the heat exchanger 50 shown in FIG. 1.

In an advantageous embodiment, the outer skin areas used with the arrangement according to the invention can be provided on their outer surface with an additional selective coating which reduces the reflection. For example, Bricks are coated in such a way that the reflection in the range of 80-120 my is selective and rays in this area are not allowed to pass. Either ceramic paints, ceramic embossing paints for tiles or, in the case of old roof tiles, coating paints can be applied as the coating. Old roofs should be treated beforehand with a cleaning fluid and then applied with an anti-corrosion material.

Claims

15 patent claims

Arrangement for absorbing energy which acts as radiation and / or thermal energy from the external environment of a building on areas of the outer skin of the building,

- With a layer of heat-insulating material (20, 70), which is arranged under selected outer skin areas (10; 82), air convection channels (41, 42) being formed between this layer and the outer skin areas, and

- With an air transfer device (45) for transferring air from the air convection channels (41, 42) to a Nu heat sink (50), characterized in that I

- An air-permeable dry absorber (30) with high radiation absorption capacity and high thermal conductivity is arranged within the air convection channels (41, 42), which extends essentially parallel to the outer skin (10; 82) over the length and width of the air convection channels (41, 42), and

- The air transfer device (45) conducts that air which has flowed through the dry absorber (30) to the useful heat sink (50).

.Arrangement according to claim 1, d a d u r c h g e k e n n z e i c h n e t, d a ß

- The dry absorber (30) at a distance from both the outer skin (10; 82) and the heat-insulating layer

(20; 70) is arranged to divide the air convection channels (41, 42) into a primary flow chamber (41) facing the outer skin (10; 82) and a secondary flow chamber (42) facing the heat-insulating layer (20; 70) , and - The air transfer device (45) conducts air from the secondary flow chamber (42) to the useful heat sink (50).

3. Arrangement according to claim 2, characterized in that the exhaust air outlet of the useful heat sink (50) is connected to a supply air inlet (43) of the air convection channels.

4. Arrangement according to claims 2 and 3, characterized in that the supply air inlet (43) of the air convection channels leads into the primary flow chamber (41).

5. Arrangement according to one of the preceding claims, characterized gekennz e i chnet that the air convection channels (41, 42) at least on that part of its inner surface, which is to the heat-insulating layer

(20; 70) lies down, has a heat reflecting coating.

6. Arrangement according to one of the preceding claims, characterized gekennz e i chnet that the dry absorber (30) is a black matt metal knitted fabric.

7. Arrangement according to claim 6, characterized in that the dry absorber (30) has several layers of black lacquered aluminum expanded metal.

8. Arrangement according to claim 7, characterized in that the total thickness of the dry absorber (30) is in the range from 16 to 20 mm. 17

9. Arrangement according to one of claims 6 to 8, since by gekennz ei chne t that the effective surface of the dry absorber (30) is 3.6 to 4 m ² / m ² .

10. Arrangement according to one of the preceding claims, characterized in that the selected outer skin areas (10) are areas of the roof skin.

11. The arrangement according to claim 10, characterized in that the selected outer skin regions (10) have clay or concrete tiles or natural or artificial slate elements laid on slatted frame.

12. Arrangement according to one of claims 1 to 10, characterized by marked that the selected outer skin areas have corrugated sheets of mineral fiber cement or hard fiber bitumen.

13. Arrangement according to one of claims 1 to 10, characterized by marked that the selected outer skin areas have corrugated or trapezoidal sheet steel.

14. Arrangement according to claim 13, characterized in that the steel sheet is galvanized on the outside and painted black matt.

15. Arrangement according to one of claims 1 to 10, since by gekennz e i chnet that the selected outer skin areas have black-oxidized copper sheet.

16. Arrangement according to one of claims 1 to 9, characterized in that ß the- selected areas of the outer skin are side wall areas of the building and consist of the outer walls (82) of hollow blocks (80), the cavities of which form the air convection channels (41, 42).

17. The arrangement according to claim 16, characterized in that the air convection channels (41, 42) run vertically and the supply air inlet (43) of the air convection channels is located near their lower ends and the exhaust air outlet of the air convection channels is located at their upper ends.

18. Arrangement according to claim 16 or 17, characterized gekennz ei chne t that the supply air inlet 43) of each air convection channel (41, 42) is a lateral opening, each of which is a connection to an adjacent supply air channel (95), in addition to which the Hollow stones (80) containing air convection channels (41, 42).

19. The arrangement according to claim 18, characterized in that the supply air ducts (95) run between adjacent hollow stones (80) containing air convection ducts (41, 42).

20. Arrangement according to one of claims 16 to 19, since by gekennz e i chnet that the supply air channels (95) are also formed by hollow blocks (90) which are substantially coplanar with the hollow blocks containing the air convection channels (41, 42)

(80) extend.

21. Arrangement according to one of claims 16 to 20, as by gekennz ei chnet that the hollow bricks (80, 90) are hollow bricks made of fired clay. 19

22. Arrangement according to one of claims 16 to 21, since by gekennz e i chnet that the heat-insulating layer (70) is a masonry of heat-insulating bricks (71).

23. The arrangement according to claim 22, characterized in that the heat-insulating bricks (71) are poroton bricks.

24. Arrangement according to one of the preceding claims, characterized gekennz e i chnet that the selected outer skin areas are provided on their outside with a heat-reducing coating.

25. Arrangement according to one of the preceding claims, characterized in that the air transfer device contains a line system with a fan (45).

26. Arrangement according to one of the preceding claims, characterized in that the useful heat sink (50, 66) contains a heat exchanger (50).

27. Arrangement according to one of the preceding claims, characterized gekennz e i chnet that the useful heat sink (50, 66) has a long-term heat storage

(66) contains.