EP3658733B1 - Building facade system having hygroscopic and auto-reactive dehumidification mechanism - Google Patents

Description

Technical area

The present invention relates to a building facade system with a hygroscopic and auto-reactive dehumidifying mechanism. The invention relates in particular to a double facade, such as, for example, a closed-cavity facade, with a hygroscopic and auto-reactive dehumidification mechanism that manages without additional control or complex maintenance.

Technical background

With conventional double façades, the space between the shells, in which there are mainly mechanical sun protection components, is dimensioned in such a way that it can be accessed primarily for cleaning but also for maintenance purposes. Because of the constant exchange with the outside air, this gap is exposed to contamination that occurs, for example, from sand, insects or other particles in the air. In recent years, facades with a closed and maintenance-free space between the facades have become ready for the market. This so-called "Closed Cavity Façade" is a special type of double-shell facade, which usually has a very high proportion of glazing and in which the space between the two glazings or shells (also called "Cavity" in the following) is a space closed off from inside and outside air forms.

The tightness and seclusion of the space between the façade is a central product idea, because this is supposed to prevent soiling of the components protected from the wind, such as the sun protection, in the space between the shells prevent. Thus, according to the manufacturers, this space no longer has to be made accessible for cleaning purposes, which has a decisive advantage over facade constructions with open shells: The smaller depth of the space enables a corresponding increase in the usable area of the interior with the same external dimensions of a building. While the double facades built around the world in the last few decades have a facade gap of up to one meter deep, this application shows a reduction in depth of up to 10-15 cm. This gain in space multiplies with the number of storeys in the building.

In addition, the space between the facade does not need any additional cleaning measures, as it is completely sealed from the outside and inside and ventilated with clean air. This is made possible by a continuous supply of dry and clean air and a slight overpressure in the closed cavity. The aim of this measure is to prevent the condensation of water vapor caused by temperature fluctuations and thus fluctuating relative humidity. The amounts of air that are introduced into the cavity are preconditioned, in particular dried. In some applications, the air can optionally be adjusted to different temperatures by building services systems. The dehumidified air, which is introduced into the space with a constant overpressure, prevents condensation, which occurs in conventional double-shell facades, especially in the lower area of the inside of the (outer) glazing, especially if the temperature fluctuates within a day. In the transitional periods in particular, in conventional double facades that are not supplied with preconditioned air, temperature fluctuations occur due to solar heating during the day and the exchange of radiation between the facade surfaces and space and thus strong cooling of the outer pane. The dehumidified and clean air in the cavity of the conventional closed cavity façade tries to avoid condensation. However, the disadvantage here is the technical effort involved in dehumidifying the cavity, for example for providing the preconditioned and dehumidified air as described above or other dehumidifying measures. Other manufacturers have developed products with a diffusion-open edge bond of the cavity, which enables a regulated and self-sufficient compensation of pressure and humidity of the cavity with the outside environment enable. A controlled equalization of the cavity with the outside environment should prevent the formation of condensation. This technology is sold by the company Seele under the name "SCF", "Self Conditioning Façade"

EP 2441910 A1 discloses a double facade element for buildings comprising an inner pane arrangement with at least one glass pane and an outer pane arrangement with at least one glass pane, each of which is held by a frame arrangement, the frame arrangement having at least one pressure compensation opening which connects the space to the atmosphere.

This solution effectively prevents condensation in the space between the panes of the facade. However, the mechanical elements require maintenance.

DE 10 2015 219302 A1 discloses a ventilation device for controlled air exchange between indoor air of an interior and outside air of the outside environment of the interior through a ventilation duct, wherein a first variable sealing arrangement is present, which is set up to seal the ventilation duct depending on the humidity of the interior air, the ventilation device being designed as a window , wherein the ventilation channel is arranged between a sash frame and a window frame of the window.

Brief description of the invention

The present invention provides a building facade system that effectively overcomes the disadvantages of the prior art. The disclosure that follows will provide a better understanding of the invention as defined by the appended claims.

In a preferred embodiment of the disclosure, a building facade system is provided that includes a frame structure; an outer pane which is held by the frame structure and forms an interface with the outside air; an inner pane, which is held by the frame structure, with the outer pane is spaced apart and which is arranged facing the building. The frame construction defines a space between the panes with the outer pane and the inner pane. The frame construction further comprises a first opening that allows a gas flow between the outside air and the space between the panes, a first closure mechanism that closes the first opening in a substantially airtight manner, and a first moisture-responsive control element that is in communication with air in the space between the panes and that the The first locking mechanism opens or closes via a moisture-reactive change in dimension of the control element, which depends on the relative humidity in the space between the panes.

The frame construction according to the invention furthermore comprises a second opening which allows a gas flow between the outside air and the space between the panes, wherein the second opening can also be opened or closed via the first closure mechanism and the first moisture-reactive control element. The first and the second opening are opened at the same time by the first locking mechanism and a ventilation or draft effect occurs immediately. This can be reinforced by a chimney effect if, for example, the first opening is arranged in a lower frame area and the second opening is arranged in an upper frame area. This is particularly preferred since the direction of the air flow through the cavity is determined and corresponding optional filters or dehumidification measures, as described below, only have to be provided at one of the openings, since the other only serves for the exit of the air flow. This can be further ensured by interposed valves (e.g. valve flaps).

The use of a locking mechanism that opens or closes the control element via a moisture-reactive change in dimensions means that complex sensors and correspondingly controlled electronics and mechanical components are superfluous. The moisture-reactive control element is auto-reactive, ie it reacts automatically to changed environmental conditions, and by suitable adaptation of the transfer of the dimensional change to the locking mechanism, dehumidification is achieved through automatic ventilation of the cavity or the space between the panes.

The moisture-reactive control element reacts particularly preferably to the change in the relative humidity. If the relative humidity in the cavity is high, e.g. as a result of the ambient air cooling down in the evening and the lack of solar radiation, the control element reacts, e.g. with a linear expansion. This is transferred to the locking mechanism, which opens the opening and starts ventilation of the cavity. Only relatively drier air gradually replaces the relatively humid air of the cavity, whereby the control element contracts again and the locking mechanism closes. There is no condensation because the air in the cavity is quickly warmed up again to a higher temperature than that of the outside air due to its proximity to the building.

In a preferred embodiment of the present disclosure, the distance between the outer and inner panes is from 70 mm to 250 mm, preferably from 100 mm to 150 mm. These distances are only preferred dimensions of so-called "closed cavity" facades and should not be understood as restrictive. Facades with lesser or greater spacing between the panes, such as other types of double facades, can also benefit from the present invention.

In a preferred embodiment of the present disclosure, the closure mechanism is a flap which is opened or closed via a lever by changing the length of the control element. The invention can, however, be implemented with different locking mechanisms as are familiar to the person skilled in the art. For example, actuators, stamps, bottle or cable systems, gear wheels, hydraulic transmissions and sliding windows and doors are conceivable as locking mechanisms, either alone or in combination with one another.

In a preferred embodiment of the present disclosure, the moisture-reactive control element has a strip shape and is made from an extruded, cast, braided and / or rolled moisture-reactive material. This embodiment uses a change in length of the strip to control the closure. Usually, elements with a large surface area, such as several parallel, very fine fibers, are preferred, as this reduces the effects of the Dimensional change, such as the change in length, increased. In another embodiment of the disclosure, the moisture-reactive control element is made from a woven and / or braided moisture-reactive material. Here, too, the finer the fibers used, the larger the area that can react with the ambient air, more precisely with the water vapor contained therein, which also increases the dimensional change of the control element.

In a preferred embodiment of the present disclosure, the moisture-reactive control element comprises a hygroscopic plastic from the group of polyamides. In a more specific embodiment of the present disclosure, the moisture-reactive control element consists of the hygroscopic plastic from the group of polyamides.

The hygroscopic plastic can preferably be selected from PA6, PA66, PA11, PA12 or mixtures or copolyamides of two or more (co) polyamides from this group. It should be understood, however, that the invention is not restricted to specific moisture-reactive substances and that other substances, such as natural fibers or other classes of plastic, can also be used. The only important thing is to change the length or volume of the substance when it absorbs water.

In a preferred embodiment of the present disclosure, the frame construction also comprises a second opening which allows a gas flow between the outside air and the space between the panes. However, for this opening there is a second closing mechanism which closes the second opening in a substantially airtight manner, and a second moisture-reactive control element which is in communication with air in the space between the panes and which opens or closes the second closing mechanism via a moisture-reactive dimension change of the control element, which is determined by the relative humidity in the space between the panes is provided. It should be noted at this point that the first and the second locking mechanisms can also each open or close openings in two adjacent facade systems. This is possible because the moisture conditions in two adjacent facade modules are usually very similar and can accordingly be ventilated at the same time.

By using two independent opening mechanisms for the first and the second opening, the strength of the ventilation of the cavity can be graded. E.g. if the air is slightly too humid, but it does not necessarily lead to condensation of water vapor, only one of the two locking mechanisms and a slower ventilation of the cavity occurs. In addition, it is desirable that, in the case of using the chimney effect, the air inlet opening of the cavity is opened in front of the outlet opening. Otherwise, dirt particles or non-dehumidified air could enter through the second opening. It should be noted at this point, however, that both openings can be equipped with particle filters or dehumidification measures.

In a preferred embodiment of the present disclosure, the first opening comprises a particle filter and / or a dehumidifying means. These are used to clean and dehumidify the penetrating air and can also be provided on the second opening. In preferred embodiments, the particle filter comprises a cotton filter, a Gore Tex membrane filter, a dry filter, an electrostatic filter, a sieve filter or an inertia filter. Furthermore, in preferred embodiments, the dehumidifying agent comprises aluminum silicate, zeolite, a pNIPAAm polymer, a combination of pNIPAAm polymer and cotton or a superabsorbent (SAP). It should be understood that the above-mentioned filters and dehumidifiers can be provided both individually and in combination with one another, e.g. by connecting several filters and / or dehumidifiers in series in the air flow entering the cavity.

It should also be noted that further elements, e.g. shading devices or panes, can be arranged between the outer pane and the inner pane. In the case of additional panes, additional spaces between panes can either be in sufficient gas exchange with one another or, as an alternative, additional dehumidification measures are provided for additional spaces in accordance with the description above.

In accordance with the above disclosure, it is an object of the present invention to create a solution that allows the space between the façades of a closed cavity façade to be dehumidified without the use of external energy if there is a condensation problem.

Brief description of the drawings

• Fig. 1 Figure 12 shows a building facade system in accordance with a preferred embodiment of the present disclosure.
• Figures 2A through 2D each show a schematic building facade system according to a preferred embodiment of the present disclosure in different situations.

Description of the disclosed embodiments

The present invention is described below with reference to figures which schematically show various exemplary embodiments of a building facade system according to the invention. The embodiments shown in the figures are not shown to scale, with dimensions being selected in some cases which bring out the principle of the present invention more clearly.

Both in the description and in the figures, the same or similar reference symbols are used to refer to the same or similar elements or components. In order to keep the description concise, elements that have already been mentioned in other figures are not necessarily mentioned again explicitly in the description of each further figure.

Fig. 1 Figure 10 shows a building facade system 100 in accordance with a preferred embodiment of the present disclosure. The building facade system according to Fig. 1 comprises a frame construction 150. The frame construction does not have to be modified in addition to the known prior art in order to implement the present invention. Only the openings and the control over the Locking mechanisms 112 and 122 or the control elements 114 and 124, as they are described further below, must find space in the frame structure.

The building facade system 100 further comprises an outer pane 140, which is held by the frame structure 150 and forms a boundary surface with the outside air B. The direct contact between outside air B and outside pane 140 means that water vapor preferentially condenses on this when the outside temperature drops sharply (e.g. at night). This phenomenon is intended to be suppressed by the present invention.

The building facade system 100 further comprises an inner pane 130, which is held by the frame structure 150, is spaced apart from the outer pane 140 by a distance A, and which is arranged facing the building C. The frame structure 150 defines, with the outer pane 140 and the inner pane 130, a space 160 between panes, also referred to as a cavity in the present description. The frame structure 150 also includes a first opening 110 in the lower region thereof, which allows a gas flow between the outside air and the space between the panes. The opening is not limited in the present disclosure. However, a sufficient size is desirable in order to enable sufficient gas exchange. As an alternative to the in Fig. 1 Indicated individual first opening, several first openings can also be provided.

The first opening 110 can be closed in a substantially airtight manner by a first closing mechanism 112. Suitable sealing elements (not shown) are preferably provided in the contact area between the opening and the closure. The locking mechanism 112 is actuated, ie opened or closed, by a first moisture-reactive control element 114. The control element 114 is in communication with air in the space between the panes 160 and opens or closes the shutter 112 accordingly depending on the relative humidity in the space between the panes 160. In particular, the control element 114 opens the shutter 112 when the relative humidity in the cavity 160 has a preset value exceeds. A corresponding coordination of the locking mechanism 112 and the control element 114 can be implemented by a person skilled in the art with just a few attempts and will not be detailed here executed.

A second opening 120, which allows a gas flow between the outside air and the space between the panes, is arranged in the upper region of the frame structure 150, ie in the region of the upper edges of the panes 130 and 140. As in Fig. 1 As shown, a second closure mechanism 122 can be provided which closes the second opening in a substantially airtight manner. In Fig. 1 a first locking mechanism 210 of a system arranged above the illustrated facade system or facade module is also indicated.

A second moisture-reactive control element 124, which is in communication with air in the space between the panes 160 and which opens or closes the second locking mechanism 122 via a moisture-reactive change in dimension of the control element 124, which depends on the relative humidity in the space between the panes 160, is also in the upper area of the frame construction 150 provided. The second control element 124 can also actuate the adjacent first locking mechanism 210 in order to open or close an adjacent first opening (not shown).

The system according to the above description can also be provided with only a single opening and the associated closure and moisture-reactive elements. The ventilation takes place correspondingly more slowly in this embodiment. The invention is preferably used in the space between the panes of a double-shell, large-area glazed facade. Depending on the relative humidity, the cavity can be dehumidified using autoreactive, moisture-reactive materials. The autoreactive material reacts to the increasing humidity level in that the water absorption and consequently an increase in volume initiate a geometric change. The change in length or volume is preferably initiated by means of calibrated fiber ribbons (with integrated actuator-sensor functions) made of polyamide or the like (PA6, PA66, PA11, PA12 or mixtures or copolyamides thereof) in a folding mechanism that allows air to be exchanged in the cavity the environment, i.e. the natural ventilation of the space between the façades; enables.

If the humidity of the ambient air increases, the facade closes again without additional energy. Certain opening parameters can be set by utilizing the effects of the swelling kinetics and simple structural measures.

In a preferred embodiment, the inflowing air is additionally dehumidified using a drying agent (aluminum silicate, zeolite or the like). Alternatively, pNIPAAm polymers can be used to temporarily dry the cavity. The combination of pNIPAAm polymers and cotton can store and release 3.4 times its own weight in water. The material can absorb large amounts of water up to 34 ° C. At higher temperatures, however, it gives off water. Furthermore, superabsorbents (superabsorbent polymers, SAP) are also possible.

The desiccant can release moisture in a controlled manner on dry days. The process described works without auxiliary energy and is automatically reversible and therefore always possible.

In a preferred embodiment, the invention provides for the use of several polymer actuators: one is located in the lower part of the facade element (box element); the other in the upper part. A membrane (Gore-tex or similar) is used as a filter for better protection against contamination from penetrating into the cavity caused by particles. Other filter devices can alternatively be used, e.g. dry filters, electrostatic filters, sieve filters or inertial filters.

The only temporary opening to the surrounding outside air reduces the pollution of the cavity to the extent that it reduces the period of exchange with the environment and thus the entry of unclean air containing particles into the cavity.

Figures 2A through 2D each show a schematic building facade system according to a preferred embodiment of the present disclosure in different situations. Figures 2A and 2B are schematic representations of the conditions on a Summer day, especially the transition from great heat ( Figure 2A ) on the terms in the late afternoon or in the evening ( Figure 2B ). In Figure 2A it is shown that the relative humidity outside (50-75%), in the space between the panes 160 (55-75%) and inside (30-55%) are not critical per se. The high temperature difference between the cavity 160 and the interior, i.e. 50-60 ° C compared to <26 ° C (e.g. due to an air conditioning system), however, ensures a local humidity in the area of the inner pane of over 100% and condensation occurs. It is therefore necessary to provide ventilation in the interior space 160 in order to lower the temperature therein and thus to keep the relative humidity on the inner pane low so that no condensate precipitates on the pane.

This situation changes in the evening, as shown schematically in Figure 2B is shown. The outside temperature drops rapidly (15 ° C, 65-95% relative humidity) while the space between the panes 160 and the interior are still relatively warm. Too much cooling of the cavity is not desirable. Therefore, when cool outside air enters the cavity 160, it is quickly heated, the relative humidity in the cavity 160 decreases rapidly, and the dehumidifying system as described above stops ventilation. This saves energy for heating the building at night.

Fig. 2C and 2D are schematic representations of the conditions on a winter day, in particular the transition from early morning to night ( Figure 2C ) under the conditions in the morning or generally during the day ( Figure 2D ).

In the situation in Figure 2C are similar to that of the Fig.2B , Energy saving aspects important. Should the humidity in the cavity 160 rise to almost 100%, the ventilation should be triggered by the facade system described above. Cool outside air flows in and is quickly heated to approx. 5-10 ° C by the relatively warm building. The relative humidity therefore drops quickly and the ventilation is stopped again or the control element (not shown) closes the opening (not shown) via the locking mechanism (not shown). This process corresponds to the burst ventilation generally recommended in winter.

Claims (13)

1. Building facade system (100), comprising:

   a frame structure (150);

   an outer pane (140) supported by the frame structure (150) and forming an interface with the outside air (B); and

   an inner pane (130) supported by the frame structure (150), spaced from the outer pane (140) by a distance (A), and arranged to face the building (C);

   the frame structure (150) defining, with the outer pane (140) and the inner pane (130), an inter-pane space (160); the frame structure (150) comprising:

   a first opening (110) allowing gas flow between the outside air and the inter-pane space, and

   a first closure mechanism (112) adapted for closing the first opening (110) in a substantially airtight manner, the building facade system (100) being characterized in that the frame structure (150) further comprises:

   a first moisture-responsive control element (114) that communicates with air in the inter-pane space (160) and that opens or closes the first closure mechanism (112) via a moisture-responsive dimensional change of the control element (114) that depends on the relative humidity in the inter-pane space (160); and

   a second opening (120) that allows gas flow between the outside air and the inter-pane space, the second opening (120) also being opened or closed by the first closure mechanism (112) and the first moisture-responsive control element (114).
2. Building facade system (100) according to claim 1, wherein the distance (A) is from 70 mm to 250 mm, preferably from 100 mm to 150 mm.
3. Building facade system (100) according to claim 1 or 2, wherein the closure mechanism (112) is a flap which is opened or closed via a lever by a change in length of the control element (114).
4. Building facade system (100) according to any one of the preceding claims, wherein the moisture-responsive control element (114) has a strip shape and is made of an extruded, cast, braided and/or rolled moisture- responsive material.
5. Building facade system (100) according to any one of the preceding claims, wherein the moisture-responsive control element (114) is made of a woven and/or braided moisture-responsive material.
6. Building facade system (100) according to any one of the preceding claims, wherein the moisture-responsive control element (114) comprises a hygroscopic plastic from the group of polyamides, in particular homo- or copolyamides.
7. Building facade system (100) according to claim 6, wherein the moisture-responsive control element (114) consists of the hygroscopic plastic from the group of polyamides, in particular homo- or copolyamides.
8. Building facade system (100) according to claim 6 or 7, wherein the hygroscopic plastic is selected from the group consisting of PA6, PA66, PA11, PA12, or mixtures or copolyamides of two or more (co)polyamides from this group.
9. Building facade system (100) according to any one of claims 1 to 8, wherein the frame structure (150) further comprises:

   a second opening (120) that allows gas flow between the outside air and the inter-pane space,

   a second closure mechanism (122) that closes the second opening in a substantially airtight manner; and

   a second moisture-responsive control element (124) that communicates with air in the inter-pane space (160) and that opens or closes the second closure mechanism (122) via a moisture-responsive dimensional change of the control element (124) that depends on the relative humidity in the inter-pane space (160).
10. Building facade system (100) according to claim 1 or 9, wherein the first opening (110) is provided in a frame portion below the second opening (120), so that when the first and second closure mechanism (112, 122) are opened simultaneously, an air flow is generated by the chimney effect.
11. Building facade system (100) according to any one of the preceding claims, wherein a particle filter and/or a dehumidifying means is provided at the first opening to clean and/or dehumidify air entering the inter-pane space (160) through the first opening (112).
12. Building facade system (100) according to claim 11, wherein the particle filter comprises: a cotton filter, a Gore Tex membrane filter, a dry filter, an electrostatic filter, a screen filter, or an inertial filter.
13. Building facade system (100) according to claim 11 or 12, wherein the dehumidifying means comprises: Aluminum silicate, zeolite, a pNIPAAm polymer, a combination of pNIPAAm polymer and cotton, or a superabsorbent (SAP).

Images