DE29615791U1 - Double-skinned building facade - Google Patents

Description

FARMER

PATENT ATTORNEY

EUROPEAN PATENT ATTORNEY

VNR: 100 307

H. BAUER ■ AM KEILBUSCH 4 ■ D-52O8O AACHEN

Utility model registration phone 024 05/9033

FAX O 24 OS/9O34

Note: H. KRANTZ-TKT GmbH, Am Stadion 18-24, 51465 Beraisch Gladbach Name: "Double-shell building façade"

YOUR SIGNS YOUR MESSAGE MY SIGNS AACHEN-

BVMJ (4311) 22 July 1996

The invention relates to a double-shell building façade with an inner façade and a substantially transparent outer façade. Between the inner façade and the outer façade, separating elements are arranged which, together with the inner façade and the outer façade, form closed compartments. The compartments are connected to the atmosphere via at least one inlet opening and one outlet opening in the outer façade.

Such a building façade is known, for example, from EP 0 663 573 A2. The interior façade is a largely conventionally constructed façade with openable windows, in front of which is a glass façade consisting essentially of pane elements as an exterior façade. The inlet opening and the outlet opening in the exterior façade serve to ventilate the interior of the compartment, which is occasionally very hot due to solar radiation. Since the interior façade has openable windows, the rooms behind the interior façade can be naturally ventilated and heated at the same time over a large period of the year in an energy-efficient manner, i.e. using solar energy.

DEUTSCHE BANKAG AACHEN 2 502 631 POSTAL GIRO ACCOUNT COLOGNE 23 13 33-508. VAT NO.DE 123 60 97 SS

(Bank code 390 700 20) (Bank code 370 100 50) Hubert Bauer, Im Reichswald 30

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The use of such double-shell building facades also makes it possible to have natural ventilation of high-rise buildings, i.e. ventilation that does not require air conditioning, since the very high wind pressure that can occur with single-shell facades is largely dissipated on the outer facade and the air exchange in the rooms can be influenced by the size of the openings in the outer facade.

Furthermore, the external facade has a significant soundproofing function, so that if the inlet and outlet openings are designed accordingly, openable windows can be provided in busy or otherwise noisy areas. Furthermore, sun protection can be installed in the compartments between the external and internal facades, which protects it from the effects of the weather, such as dirt and wind pressure. In particular, the wind force loads that occur on sun protection devices lead to considerable structural effort in terms of strength when installed unprotected, especially in the case of adjustable systems on tall buildings.

In addition to these advantages, the well-known double-shell building facades have the serious disadvantage in summer that the air in the compartments heats up considerably compared to the outside air, which can only be inadequately prevented by ventilating the compartments. If the windows in the interior facade are opened in such a case, much warmer air enters the room than would be the case with conventional single-shell facades, where the outside air is supplied directly. Ventilation with the overheated air from the compartments leads to increased cooling effort in the affected rooms or - if cooling is not used - to a higher room air temperature compared to the outside air temperature.

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This effect of overheating the air in the compartments can only be partially prevented by the forced ventilation of the compartments proposed in EP O 663 573 A2 with a ventilation system controlled depending on the temperature or the energy irradiation. In addition, this solution is very energy-intensive or - if photovoltaic elements are used in the external facade to supply energy to the ventilation systems - very costly.

Finally, DE 295 08 423 U1 discloses a ventilation device for double-walled building facades, which are divided into individual sections by separating elements and can be connected to the atmosphere via closable inlet and outlet openings. To increase air circulation in the compartments, box-shaped ventilation shafts are arranged at the opening cross-sections, each with a pivoting closure flap. To achieve the lowest possible flow resistance, these ventilation shafts have drop-shaped slats arranged at the inlet and outlet openings and curved air baffles, which are intended to prevent detachment and turbulence when the air flows through the compartment.

But even with this well-known facade, despite the flow-optimized ventilation of the compartments, it is not possible to prevent the temperature inside the compartment from rising significantly above the outside temperature when there is strong sunlight. Ventilation of the rooms via the windows in the interior facade therefore leads to an extremely undesirable increase in temperature in summer.

The invention is based on the task of creating a double-shell building façade which, on the one hand, enables the use of solar energy gains inside the compartments when ventilating the rooms in times of comparatively low

Solar energy radiation is enabled and, on the other hand, it also allows ventilation of the rooms without increasing the temperature above the outside air temperature in times of high solar energy radiation.

Starting from a building façade of the type described at the outset, this object is achieved according to the invention in that a passage opening arranged in the inner façade to the interior of a room can be connected to at least a partial area of the inlet opening via a ventilation duct provided with a shut-off element and separated or separable from the rest of the compartment.

The building facade according to the invention therefore has a ventilation duct that is separated or can be separated from the rest of the compartment, which allows direct ventilation of the room with outside air. Even at times when the air inside the compartment is significantly overheated compared to the outside air due to strong sunlight on the outside facade, comparatively cool outside air can be supplied to the room. However, at times when the outside air temperature is too low for direct ventilation of the room, the passage opening can be closed using the shut-off element arranged in the ventilation duct, so that cool air can be prevented from entering the room, for example in the winter months.

An embodiment of the building facade according to the invention provides that the inlet opening is arranged directly above a floor of the compartment and the passage opening is arranged below a heating device arranged on or in front of a room wall.

If the temperatures in summer are too high for room ventilation via the window due to solar heat gains in the compartment, the cooler outside air is drawn in directly through the ventilation duct and the passage opening according to the invention.

into the interior of the room. Due to the buoyancy in the compartment and the vertically upward flow that occurs, the room is essentially only ventilated even when the window is open, with cool air flowing in through the ventilation duct near the floor of the room - as with known so-called source air systems - and rising upwards as a result of heating in the room. The heated room air is then discharged back outside through the open window and the flow through the compartment.

In further developing the invention, it is proposed that the inlet opening is divided into two sub-areas arranged one above the other, with the lower sub-area being connected to the ventilation duct.

This design ensures that ventilation of the compartment is ensured regardless of the flow through the ventilation duct. Because the lower part of the inlet opening is connected to the ventilation duct, the air flow serving as a source air flow through the ventilation duct and the air flow serving as a vent flow through the compartment can advantageously be drawn in parallel through the same inlet opening.

It is also particularly advantageous to design the shut-off element as a pivoting flap which, in an open position, forms a wall part of the ventilation duct that separates the ventilation duct from the rest of the compartment and, in a closed position, releases a connecting cross-section between the ventilation duct and the rest of the compartment.

Because a connecting cross-section is released between the ventilation duct and the rest of the compartment when the flap is in the closed position, both sections of the inlet opening act as inlet openings into the compartment when the flap is in the closed position. This enlarged inlet cross-section into the

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Particularly in the transitional seasons, i.e. when there is less sunlight, the compartment has the advantage that increased ventilation of the compartment can be achieved when there is no wind. This increased ventilation is particularly necessary when there is no sunlight in order to avoid disadvantageous condensation phenomena in the compartment, which would always occur if air from the room laden with moisture were to condense on comparatively cool surfaces in the compartment in the area of the external facade. Such condensation phenomena can be prevented due to the increased ventilation cross-section.

Furthermore, it is provided that a wall of the ventilation duct is formed by a separating element, since this can reduce the construction effort for the building facade according to the invention.

It is also particularly advantageous if the separating elements and/or the walls of the ventilation duct are made of a sandwich material with low thermal conductivity.

This is an advantage because it prevents heat exchange between the compartment, in which unpleasantly high temperatures prevail in summer, and the ventilation duct, which is intended to allow the coolest possible outside air to be supplied into the room. Furthermore, in winter, when the pivoting flap closes the opening in the room wall, it is important that no unnecessarily large heat losses occur in the room as a result of heat conduction through the flap.

The entry of coarse dirt into the room through the ventilation duct can be prevented if a perforated sheet or grating is inserted into the opening.

In cases where it is desired to supply air cooled to below the outside air temperature into the room in summer, it is advisable to insert a heat exchanger into the passage opening that essentially fills its cross-section and whose width corresponds approximately to the thickness of the room wall.

Without requiring additional space, the temperature of the air supplied through the ventilation duct can be significantly reduced.

The volume flow through the ventilation duct can be drastically increased by arranging an air conveying device in the ventilation duct, whereby the air conveying device is advantageously arranged in the direction of air flow in front of the shut-off element, since such an arrangement also allows forced ventilation of the compartment when the pivoting flap is in the closed position and thus a connection is established between the ventilation duct and the compartment.

It is particularly advantageous to use a roller fan as the air conveying device, which has a comparatively elongated inlet cross-section.

Even the finest dirt particles in the air and pollen can be kept out of the ventilated room if an air filter is installed in the ventilation duct in the direction of air flow in front of the heat exchanger. In this way, the contamination of the heat exchanger can be drastically reduced and the required maintenance effort can be reduced.

According to a further development of the building facade according to the invention, it is also proposed that the width of the partial area of the inlet openings connected to the ventilation duct and the width of the outlet openings correspond approximately to half the width of the associated compartments, with the lower partial areas of the inlet openings and the outlet openings of two adjacent compartments arranged one above the other being arranged offset from one another. - 8 -

This design can prevent the heated air emerging from the outlet opening of a lower compartment from entering the inlet opening of the ventilation duct of the compartment above, which would impair the effect of supplying comparatively cool outside air. According to the invention, such a short-circuit flow is reliably avoided by the fact that the inlet to the ventilation duct of the upper compartment is completely next to the outlet opening of the compartment below. Such a staggered arrangement of the inlet and outlet openings can be achieved without affecting the appearance of the building facade by covering the inlet and outlet openings with diagonally inclined slats. It is therefore not apparent that the actual width of the inlet and outlet openings is only half the width of the associated compartment. The closed areas of the compartment provided with slats are covered with a sheet material, for example, from behind, i.e. from the inside of the compartment.

Advantageously, the shut-off element is adjustable depending on the difference between the temperature in the compartment and the temperature in the room and/or the temperature of the atmosphere. Completely automatic regulation, which does not require any intervention by the room user, can be achieved by providing a motor operated by a controller to adjust the shut-off element.

The invention is explained in more detail below using an embodiment shown in the drawing. It shows:

Fig. 1 shows the building façade according to the invention in cross section;

Fig. 2 a view of the building façade;

Fig. 3 the flow conditions that occur when the

Swing flap in the open position; - 9 -

Q'

Fig. 4 as Fig. 3, but with the

swing flap;

Fig. 5 as Fig. 3, but with a arranged in the passage opening

net heat exchanger;

Fig. 6 as Fig. 5, but with the

swing flap;

Fig. 7 as Fig. 6, but with a arranged in the ventilation duct!

nice fan;

Fig. 8 as Fig. 7, but with the

Swing flap, and

Fig. 9 a view of the building facade with offset

arranged inlet and outlet openings.

Fig. 1 and 2 show a double-shell building facade, which consists of a conventionally constructed inner facade 1 with openable windows 2 and an outer facade 4 formed essentially by transparent glass elements 3. Between the inner facade 1 and the outer facade 4, a large number of horizontal and vertical separating elements 5 and 6 are arranged, which together with the inner facade 1 and the outer facade 4 form closed compartments 7. The compartments 7 are connected to the atmosphere via an inlet opening 8 in the outer facade 4 and via an outlet opening 9 also in the outer facade 4. In a room wall 10 forming part of the inner facade 1, a passage opening 13 is arranged below a heating device 12 facing the interior of a room 11, which passage opening 13 leads to the interior of the

Room 11 is connected to a lower part 15 of the inlet opening 8 via a ventilation duct 14 that can be separated from the rest of the compartment 7. A pivoting flap 16 that forms a shut-off element is arranged within the ventilation duct 14 and, in an open position, forms a wall part of the ventilation duct 14 that separates the ventilation duct 14 from the rest of the compartment 7. In a closed position, however, the pivoting flap 16 releases a connecting cross-section 17 between the ventilation duct 14 and the rest of the compartment 7. In Fig. 1, the pivoting flap 16 takes up an intermediate position between the open position and the closed position, so that there is a connection between the lower part 15 of the inlet opening 8 and the passage opening 13 as well as with the connecting cross-section 17.

The separating element 5 forming the bottom of the compartment 7 simultaneously forms the lower wall of the ventilation duct 14. The separating elements 5 and 6 as well as an upper wall 18 of the ventilation duct 14 (including the pivoting flap 16) consist of a sandwich material with good heat insulation. Between the inner facade 1 and the outer facade 4, in the area of the window 4, there is a sun protection device S, the construction of which can be comparatively simple and therefore inexpensive due to the protected position between the facades.

Two perforated plates 20 are inserted into the passage opening 13, which prevent the penetration of coarser dirt into the interior of the room 11. The inlet opening 8 is divided into two sections 15 and 19 arranged one above the other, where the upper section 19 is arranged above the ventilation duct 14 and is therefore always connected to the interior of the remaining compartment 7.

Fig. 3 shows the flow conditions that arise both inside the compartment 7 and inside the room 11 when the pivoting flap 16 is in an open position and the ventilation duct 14 is above the lower

Partial area 15 of the inlet opening 8 and via the passage opening 13 establishes a connection between the atmosphere and the interior of the room 11.

The opening position of the pivoting flap 16 is appropriate and useful if the air inside the compartment 7 is very hot due to strong sunlight on the outer facade 4. In this case, direct ventilation of the room 11 through the window 2 is prohibited.

However, the ventilation duct 14 allows comparatively cool outside air to enter directly without heating up in the compartment 7. This comparatively cool outside air exits through the passage opening 13 in the floor area of the room 11, so that a kind of source air principle is implemented. The incoming outside air heats up and can, for example, exit back into the compartment 7 through the tilted window 2. Such an exit of air from the room 11 is significantly supported by the fact that there is a strong upward flow in the compartment 7 due to the thermals, with the air entering through the upper part 19 of the inlet opening 8 and the air exiting through the outlet opening 9. Due to this flow through the compartment 7, despite the open window 2, no overheated air enters the interior of the room 11 from the compartment 7, but only the previously described extraction of heated room air.

Fig. 4 shows the flow conditions that arise when the swivel flap 16 is in the closed position. A passage opening 13 that is closed in this way is indicated when the outside air temperature is lower than a temperature that is perceived as comfortable in the room 11. Because the swivel flap 16 in the closed position opens up a passage cross-section 17 between the ventilation duct 14 and the rest of the compartment, the entire compartment 7 is now connected to the environment via both the lower part 15 and the upper part 19 of the inlet opening 8. This is particularly advantageous when at times of low

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Air movement and lack of sunlight on the outer facade 4, condensation phenomena inside the compartment 7, namely on comparatively cold surfaces near the outer facade 4, are to be feared. The occurrence of such condensation phenomena is prevented because the circulation is increased by the now significantly larger inlet opening 8.

If, when the pivoting flap 16 is closed, the temperature inside the compartment 7 is higher than the desired temperature in the room 11 due to direct or diffuse solar radiation, the room 11 can be ventilated in an energetically advantageous manner and heated at the same time by opening the window 2. If such heating via air from the compartment 7 is not possible, the heating device 12 ensures that the desired room temperature is achieved.

The double-shell facade shown in Fig. 5 shows a heat exchanger 21 arranged in the area of the passage opening 13, through which both a hot and a cold heat exchange medium can flow. In the open position of the pivoting flap 16 shown in Fig. 5, the heat exchanger 21 is flowed through by a cooled heat exchange medium in order to additionally cool the outside air flowing through the ventilation duct 14 and then entering the room 11. Such an approach can be advantageous, particularly when the outside air temperature is very high, in order to be able to keep the room temperature low.

The ventilation of the room 11 takes place, similar to the case shown in Fig. 3, according to the displacement air principle, whereby the heated room air exits from the tilted window 2, which is supported by the suction effect of the ventilation flow flowing through the compartment 7.

Fig. 6 shows the pivoting flap 16 in the closed position, so that the compartment 7 is in communication with the environment over the full cross-section of the inlet opening 8.

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and a correspondingly strong circulation prevails in the compartment 7. If the swing flap 16 has been closed because the outside air temperature is lower than the desired room air temperature and because otherwise unpleasant drafts would occur in the foot area, the heat exchanger 21 used for cooling in the previously described case can now also be used as a heating device, provided that a heated heat exchange medium flows through it. Due to the position of the heat exchanger, which is not optimal in terms of flow for heating, a relatively weak warm air flow occurs on the inside of the room wall 10, which, however, does not require a separate radiator on the room wall 10 to cover only a small heat requirement. An exchange of air takes place between the room 11 and the compartment 7 via the tilted window 2, with flows taking place in both directions.

In the building façade shown in Fig. 7, the ventilation duct 14 additionally has an air conveying device in the form of a roller fan 22 arranged in the direction of air flow in front of the pivoting flap 16 and in front of the heat exchanger 21 located in the room wall 10. Due to the now forced air flow through the ventilation duct 14, an air filter 23 can be arranged in front of the heat exchanger 21, which both prevents contamination of the heat exchanger 21 and enables the separation of the finest particles from the outside air, such as dust, soot or pollen.

Operating the roller fan 22 is particularly advantageous in the summertime during the night hours, in order to introduce large amounts of comparatively cool outside air into the interior of the room 11 or the entire building. In this way, the building can be noticeably cooled overnight, whereby, due to the avoidance of long intake ducts, no noticeable heating of the intaken outside air occurs when it flows through the ventilation duct 14. Due to its short length, the existing heat storage capacities are very low. - 14 -

Another very useful application of the roller fan 22 is shown in Fig. 8. In this case, the pivoting flap 16 is again in a closed position, so that the entire cross-section of the inlet opening 8 is connected to the compartment 7. By operating the roller fan 22, the circulation within the compartment 7 is increased again significantly if necessary, so that condensation within the compartment is excluded even in very unfavorable weather conditions or when a high level of moisture is released from the room 11. The heat exchanger 21 is again used as a heating device in the case shown and therefore makes a conventional heating device in the parapet area of the window 2 superfluous.

The modified double-shell building facade shown in Fig. 9 is essentially identical to the facade shown in Fig. 2. In contrast to this, however, the facade shown in Fig. 9 has a lower section 15' of the inlet opening 8', the width 24 of which corresponds to only half the width 25 of the compartment 7. Furthermore, the width 26 of the outlet opening 9' also corresponds to only half the width 25 of the compartment 7. The lower section 15' of the inlet opening 8' and the outlet opening 9' of adjacent compartments 7 arranged one above the other are arranged offset from one another, so that the heated exhaust air does not escape from the compartment 7 below below the lower section 15' of the inlet opening 8', which could cause a short-circuit flow under certain circumstances. Rather, the heated air flows from the compartment 7 below through the outlet opening 9', which is offset next to the lower area 15' of the inlet opening 8' and thus essentially past the intake area of the ventilation duct 14. However, the upper part 19 of the inlet opening 8' extends, as in the previously shown embodiments, over the entire width 25 of the compartment 7 in order to ensure its optimal ventilation.

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The appearance of the external facade 4 must not be adversely affected in any way by the previously described measure of the offset arrangement, since it is not possible to see from the outside whether there is actually an opening behind the slats used to cover the inlet opening 8' and the outlet opening 9' or not. The areas not used as opening cross-sections can, for example, be covered with a glass or sheet metal element in such a way that this is not recognizable from the outside. The left half of the slat area next to the outlet opening 9' shown cross-hatched in Fig. 9 does not actually differ from the outlet opening 9' when viewed from the outside.

If space permits, it is also possible to provide an appropriate distance between the outlet opening and the part of the inlet opening connected to the ventilation duct in order to avoid a short-circuit flow, so that this undesirable effect can no longer occur.

Claims (15)

Protection claims: 1. Double-shell building facade with an inner facade and a substantially transparent outer facade, separating elements arranged between the inner facade and the outer facade, which together with the inner facade and the outer facade form closed compartments, which are connected to the atmosphere via at least one inlet opening and one outlet opening in the outer facade, characterized in that a passage opening (13) arranged in the inner facade (1) to the interior of a room (11) can be connected to at least a partial area (15, 15') of the inlet opening (8, 8') via a ventilation duct (14) provided with a shut-off element and separated or separable from the rest of the compartment (7). 2. Building facade according to claim 1, characterized in that the inlet opening (8, 8') is arranged directly above a floor of the compartment (7) and the passage opening (13) is arranged below a heating device (12) arranged on or in front of a room wall (10). 3. Building facade according to claim 1 or 2, characterized in that the inlet opening (8, 8') is divided into two sub-areas (15, 15'; 19, 19') arranged one above the other, the lower sub-area (15, 15') being connected to the ventilation duct (14). 4. Building facade according to one of claims 1 to 3, characterized in that the shut-off element is designed as a pivoting flap (16) which, in an open position, forms a wall part of the ventilation duct (14) separating the ventilation duct (14) from the rest of the compartment (7) and, in a closed position, releases a connecting cross-section (17) between the ventilation duct (14) and the rest of the compartment (7). - 17 - • 6 · • ·· I ···
¹ * * \ * · ·« 5. Building facade according to one of claims 1 to 4, characterized in that a wall of the ventilation duct (14) is formed by a separating element (5). 6. Building facade according to one of claims 1 to 5, characterized in that the separating elements (5, 6) and/or the walls of the ventilation duct (14) consist of a sandwich material with a low thermal conductivity. 7. Building facade according to one of claims 1 to 6, characterized in that a perforated sheet (20) or grating is inserted into the passage opening (13). 8. Building facade according to one of claims 1 to 7, characterized in that a heat exchanger (21) is inserted into the passage opening (13) which essentially fills its cross-section and whose width corresponds approximately to the thickness of the room wall (10). 9. Building facade according to one of claims 1 to 8, characterized in that an air conveying device is arranged in the ventilation duct (14). 10. Building facade according to claim 9, characterized in that the air conveying device is arranged in front of the shut-off element in the direction of air flow. 11. Building facade according to claim 9 or 10, characterized in that the air conveying device is a roller fan (22). · · i - 18- 12. Building facade according to one of claims 8 to 11, characterized in that an air filter (23) is arranged in the ventilation duct (14) in the flow direction of the air in front of the heat exchanger (21). 13. Building facade according to one of claims 1 to 12, characterized in that the width (24) of the partial area (15) of the inlet openings (8') connected to the ventilation duct (14) and the width (26) of the outlet openings (9') correspond approximately to half the width (25) of the associated compartments (7), wherein the lower partial areas (15') of the inlet openings (8') and the outlet openings (9') of two adjacent compartments (7) arranged one above the other are arranged offset from one another. 14. Building facade according to one of claims 1 to 13, characterized in that the shut-off element is adjustable depending on the difference between the temperature in the compartment (7) and the temperature in the room (11) and/or the temperature of the atmosphere. 15. Building facade according to claim 14, characterized in that a motor controlled by a controller is provided for adjusting the shut-off element.