WALL PASSAGE

Abstract

 A wall passage provided to be incorporated in a wall of a building and configured to be connected to an air displacing unit, the wall passage comprising an air inlet and an air outlet, wherein provided between the air inlet and the air outlet is a sound trap which takes the form of a chamber with a chamber air inlet and a chamber air outlet between which at least a segment of the channel is situated, wherein the segment of the channel secondarily guides the airflow in a direction parallel to the wall and wherein the chamber is formed such that the airflow travels in the chamber through a substantially two-dimensional bend which lies parallel to the wall in order to prevent a linear airflow from the chamber air inlet to the chamber air outlet and so damp propagation of sound through the chamber.

Description

[0001] The invention relates to a wall passage, particularly a wall passage for an air displacing unit.

[0002] Air displacing units are used inter alia in ventilation systems which are configured to actively ventilate buildings.

[0003] BE1024294 describes for instance a local ventilation unit which can be incorporated in a cavity. This local ventilation unit is provided with air displacing units which are provided outside the space in order to allow air to flow into and out of a space in controlled manner. The local ventilation unit described in BE 1024294 is concealed fully in the cavity, so behind the inner wall and not in the space, and causes only a minimal aesthetic disruption in the space. In order to allow air to flow into and out of the space a wall passage is provided in the inner wall, which wall passage is configured to be connected to the air displacing unit. The wall passage comprises an air inlet and an air outlet. A drawback of the air displacing units is however that they produce sound which finds its way into the space via the wall passage. Because said local ventilation unit is concealed in the cavity, the distance between the air displacing units contained in the local ventilation unit and the space which is provided with air by the local ventilation unit is limited. Because this distance is limited, among other reasons, a person present in the space experiences noise nuisance from the sound produced by the air displacing units.

[0004] DE20305801U1 describes a local ventilation system wherein the incoming and outgoing air flows via a sound-damping channel. This sound-damping channel simultaneously forms the heat exchanger for exchanging heat between incoming and outgoing air. Building this solution into a wall in efficient manner is difficult due to the overall depth. It is almost impossible to finish the wall airtightly because the opening does not extend transversely through the wall.

[0005] It is an object of the invention to further limit noise nuisance in the space coming from an air displacing unit and to enable efficient incorporation.

[0006] For this purpose the invention provides a wall passage according to claim 1.

[0007] The wall passage, which comprises the sound trap, is provided to be incorporated at least partially in a wall of a building. This allows the sound trap to be concealed at least partially in the wall of the building and to realize an aesthetically attractive result. As for instance the inner shell or inner wall of the building, although the wall can also be a ceiling. The channel demarcates an airflow between the air inlet and the air outlet. The channel is thus configured to guide the air from the air inlet to the air outlet.

[0008] According to the invention, the wall passage is provided to have the air flow primarily transversely of the wall. This is functionally significant since this allows air to flow through the wall, i.e. from the one side of the wall to the other side of the wall, through an opening in the wall in which the wall passage is provided.

[0009] The wall passage is secondarily provided to make the airflow travel a distance in a direction parallel to the wall. This secondary flow direction does not contribute directly to the flow of the air through the wall, but does contribute to the reduction of sound. The invention is here based on the insight that the way in which this secondary airflow is configured or formed determines the efficiency of the wall passage. When this secondary airflow is linear, parallel to the wall, the sound damping is minimal and therefore not optimal. When this secondary airflow is not linear but divided into multiple parts, each having a different direction parallel to the wall, and these multiple parts lie adjacently of each other in a direction transversely of the wall, either the overall depth needed for integration of the wall passage is great or the cross-sectional area of the channel is small. A wall passage with a great overall depth cannot be provided in every wall, and in each case requires extensive modification of the wall due to the depth. A wall passage in which the channel has a small cross-sectional area is disadvantageous because this affects the flow resistance. A higher flow resistance requires a stronger air displacing means, whereby the latter will also produce more noise. The means for reducing the sound thus result in the need for a stronger sound source, which is not optimal.

[0010] The specific combination of features of the invention relating to the secondary airflow, being that a sound trap is provided which takes the form of a chamber with a chamber air inlet and a chamber air outlet between which at least a segment of the channel is situated, wherein the segment of the channel secondarily guides the airflow in a direction parallel to the wall and wherein the chamber is formed such that the airflow travels in the chamber through a substantially two-dimensional bend which lies parallel to the wall in order to prevent a linear airflow from the chamber air inlet to the chamber air outlet and so damp propagation of sound through the chamber, allows a high-performance sound reduction and an optimal manner of integration.

[0011] Because the chamber is formed to prevent a linear airflow, and because the bend lies parallel to the wall, the overall depth needed for such a chamber is determined by the dimensions of one air channel, more specifically the width of the channel measured in the transverse direction to the wall, so that the overall depth is optimal. Because the dimensions are not compromised, or are so to lesser extent, by the options for integration, the flow resistance can be minimized. Because a bend is provided and a linear airflow is prevented, a linear propagation of sound is also prevented, and an improved sound damping is achieved. This specific combination of features thus provides for a good sound damping, good flow and optimal manner of integration.

[0012] A two-dimensional bend is defined as a bend formed between two central flow axis segments in order to connect them such that almost the whole central flow axis lies in one plane, wherein the two central flow axis segments lie at an angle greater than 0 degrees relative to each other.

[0013] A central flow axis of the airflow in the chamber preferably lies substantially wholly in a plane lying parallel to the wall. By having the airflow flow parallel to the wall and further providing a bend which also flows parallel to the wall the central flow axis of the airflow lies in a plane lying parallel to the wall. This has been found to be optimal when integrating such a wall passage because the overall depth is determined only by the dimensions of one air channel. The flow resistance can further be minimized because this channel can be formed freely in the chamber. A wide and/or high chamber can typically be provided at least partially in a wall in considerably simpler manner than a deep chamber. By modifying the height and width of the chamber the cross-sectional area of the channel can be adjusted in order to achieve an optimized wall passage in which an optimal balance between sound damping, flow resistance and size of the wall passage has been found. The central flow axis of the airflow here preferably has a length greater than a linear distance between the air inlet and the air outlet, preferably at least 1.5 times greater, more preferably at least 2 times greater. This has been found to be optimal for the sound damping of the wall passage.

[0014] The substantially two-dimensional bend is preferably almost 180 degrees so that the segment of the channel extends substantially in a U-shape. It will be apparent here that the U-shape extends almost parallel to the wall. It has been found that this can be realized in simple manner and installed in optimal manner, while the sound damping is good.

[0015] The chamber preferably comprises a baffle for preventing the linear airflow in the plane. The baffle is particularly configured to prevent the airflow between the chamber air inlet and chamber air outlet from being completely linear. The baffle therefore also prevents sound from being able to propagate between the chamber air inlet and the chamber air outlet, and therefore also between the air inlet and the air outlet, in a substantially straight line. On one hand the baffle allows the sound waves produced by the air displacing device to be absorbed to considerable extent at the position of a chamber wall of the chamber which bounds the channel or at the position of the baffle itself.

[0016] In absorption sound waves are absorbed by the material from which the baffle is made and converted into thermal energy. On one hand the baffle further allows diffusion of sound by reflecting the sound waves at the position of the chamber wall of the chamber which bounds the channel or at the position of the baffle itself. In diffusion the sound wave is attenuated in that the sound wave is scattered in different directions by the reflection. Because the baffle on one hand absorbs sound waves and on the other hand diffuses them, the sound waves are attenuated or, in other words, weakened, and the person present in the space will experience no or less noise nuisance. In the context of the application the term "attenuate" is used synonymously with the terms "weaken" or "damp". By increasing the length of the channel the sound trap attenuates sound waves with a lower frequency, for instance 250 Hertz (Hz) or lower, in improved manner. Such low-frequency sound waves are more difficult to attenuate than high-frequency waves, at the least because the energy of the low-frequency sound wave dissipates less quickly.

[0017] The baffle is preferably arranged to force the airflow along a single primary flow path. The advantage hereof is based on the insight that the baffle increases the air resistance through the channel compared to for instance a linear channel, whereby more energy is required from the air displacing unit to guide air through the channel. This in turn causes more noise nuisance in that undesirable sound sources are created in the channel. Forcing the airflow along a single primary flow path however prevents sound sources from occurring in the channel, whereby this negative effect is substantially cancelled out or avoided.

[0018] The sound trap optionally further comprises at least one sound obstruction in the channel, which obstruction is configured to at least partially damp or reflect sound. The sound obstruction improves the absorption and diffusion of sound waves in the channel further. The sound obstruction more preferably extends at least partially in a zone of the channel. In this way the diffusion of sound waves is substantially further improved, particularly because more reflection of the sound in the channel is realized. It is noted that the sound obstruction will also absorb sound at least partially. The sound obstruction extends in the transverse direction over at least 5 mm, more preferably over at least 10 mm.

[0019] The sound trap is preferably configured to be provided upstream of the air displacing unit. The channel is more preferably configured to prevent sound from propagating from the air outlet to the air inlet. The advantages hereof are based on the insight that the prominent sound source of an air displacing device is located substantially on an air suction side thereof. Because the sound trap is provided upstream of the air displacing unit, the sound produced thereby is thus damped to optimal extent.

[0020] The sound trap is preferably configured to be connected to an inner wall of the building. This allows both the ventilation unit and the sound trap to be integrated in the outer shell or cavity and the inner shell or inner wall of the building.

[0021] The sound trap preferably comprises a frame which is configured to mount the sound trap in the wall. The chamber is more preferably connected to the frame at least partially via a hinge such that the chamber has an open state and a closed state. This allows maintenance to be performed. This further also allows said ventilation unit to be reached so that for instance functional elements, such as filters of the ventilation unit, can be replaced.

[0022] One of the chamber air inlet and the chamber air outlet is preferably provided at the position of a space between the frame and the chamber, such that air is able to flow from the space to the chamber air inlet or from the chamber air outlet to the space. The space is preferably formed here by a niche or groove in the wall of the building. This manner of integration allows air to be blown into and/or out of the space without any appreciable aesthetic disruption of the wall. A niche or groove can be provided in the wall by incorporation in the wall of the frame and the chamber, wherein air is able to flow via the niche or groove into and/or out of the chamber and so through the wall passage.

[0023] The sound trap preferably further comprises at least one first air filter in the channel. The at least one first air filter is more preferably provided at the position of the air inlet. Air can be purified via the filter. Dirt and/or vermin can also be prevented from being sucked into the space along with the air.

[0024] An inner wall of the channel is preferably provided at least partially with a sound-absorbing layer. The sound-absorbing layer is more preferably provided, at least at the position of the air outlet, with an inward-directed side of the first wall part. This improves the attenuation of the sound further.

[0025] The sound trap preferably further comprises a second chamber in line with and separate from the first chamber, which second chamber is provided to facilitate a second airflow through the wall between a second air inlet and a second air outlet.

[0026] According to a further aspect, the invention further provides a local ventilation unit connected to a wall passage as described above. This ventilation unit comprises a heat exchanger and a housing. The housing is configured to form a first channel for allowing air to flow from outside the building to inside, a second channel for allowing air to flow from inside the building to outside, and a heat exchanger provision configured for a heat exchange between an airflow in the first channel and an airflow in the second channel. The local ventilation unit is connected to the wall passage such that the chamber of the wall passage forms an extension of at least one of the first and the second channel of the ventilation unit.

[0027] The housing is preferably formed by a housing assembly comprising a first housing part and a second housing part which are mutually connectable and shape-compatible. The first housing part and the second housing part are configured to each form at least a portion of a first channel for allowing air to flow from outside the building to inside, a second channel for allowing air to flow from inside the building to outside, and a heat exchanger provision configured to receive the heat exchanger. The local ventilation unit is connected to the wall passage such that the chamber of the sound trap is preferably positioned at the air outlet of the second channel of the ventilation unit.

[0028] The invention will now be further described with reference to an exemplary embodiment shown in the drawing.

[0029] In the drawing:

figure 1 shows a section of a first exemplary embodiment of the invention;

figure 2A, figure 2B and figure 2C each show a front view of a preferred embodiment of the wall passage with sound trap;

figure 3 shows a perspective view of a further preferred embodiment of the sound trap;

figure 4 shows a schematic upright section of a ventilation unit connected to a wall passage comprising a sound trap;

figure 5 shows an exploded view of a ventilation unit with which the invention is preferably combined; and

figure 6 shows a lying cross-section of a wall at the position of the ventilation unit and the wall passage.

[0030] The following detailed description relates to determined specific embodiments. The teaching hereof can however be applied in different ways. The same or similar elements are designated in the drawings with the same reference numerals.

[0031] The present invention will be described with reference to specific embodiments. The invention is however not limited thereto, but solely by the claims.

[0032] As used here, the singular forms "a" and "the" comprise both the singular and plural references, unless clearly indicated otherwise by the context.

[0033] The terms "comprising", "comprises" and "composed of" as used here are synonymous with "including". The terms "comprising", "comprises" and "composed of" when referring to stated components, elements or method steps also comprise embodiments which "consist of" the components, elements or method steps.

[0034] The terms first, second, third and so on are further used in the description and in the claims to distinguish between similar elements and not necessarily to describe a sequential or chronological order, unless this is specified. It will be apparent that the thus used terms are mutually interchangeable under appropriate circumstances and that the embodiments of the invention described here can operate in an order other than described or illustrated here.

[0035] Reference in this specification to "one embodiment", "an embodiment", "some aspects", "an aspect" or "one aspect" means that a determined feature, structure or characteristic described with reference to the embodiment or aspect is included in at least one embodiment of the present invention. The manifestations of the sentences "in one embodiment", "in an embodiment", "some aspects", "an aspect" or "one aspect" in different places in this specification thus do not necessarily all refer to the same embodiment or aspects. As will be apparent to a skilled person in this field, the specific features, structures or characteristics can further be combined in any suitable manner in one or more embodiments or aspects. Although some embodiments or aspects described here comprise some but no other features which are included in other embodiments or aspects, combinations of features of different embodiments or aspects are further intended to fall within the context of the invention and to form different embodiments or aspects, as would be apparent to the skilled person. In the appended claims all features of the claimed embodiments or aspects can for instance be used in any combination.

[0036] In this description the terms 'incorporation' and 'to incorporate' are used as translations of the Dutch term 'inbouwen', therefore 'incorporation' and 'to incorporate' is defined as to build into. In other words, the terms to incorporate A in B is defined as to build element A into structure B.

[0037] Figure 1 shows a wall 1 of a building. The figure is unusual in that it shows different parts of the figure cut along different planes. This special representation allows an airflow to be shown in a direction transversely of the wall and in a direction parallel to the wall in a two-dimensional view. To the left of the left-hand broken line, designated with arrow A, the figure thus shows a section transversely of the wall. Between the broken lines, designated with arrow B, a section parallel to the wall is shown, and to the right of the right-hand broken line a section transversely of the wall is shown.

[0038] The wall 1 is shown schematically and is in practice typically formed by an outer wall 3 and an inner wall 2. In order to limit heat loss a cavity 4 is typically provided between inner wall 2 and outer wall 3. The cavity 4 is defined by a space between the inner wall and the outer wall, which space can be filled with air or with an insulating material. A thermal barrier is hereby created between inner wall 2 and outer wall 3 so that energy can be retained in the building. The outer wall 3 is defined as the outer shell of a building. The inner wall 2 is defined as the elements forming an inner shell of a building, wherein the inner shell is thermally insulated from the outer shell. The skilled person will appreciate that the walls can be manufactured from different types of material, such as brick, wood, plasterwork, plastic cladding and so on.

[0039] Figure 1 further shows a ventilation unit 7 which is arranged in the cavity 4. The ventilation unit 7 preferably forms part of a ventilation system and allows a forced controlled airflow from inside to outside and from outside to inside, through wall 1. The ventilation system can be deemed a local ventilation system. This is because a plurality of such ventilation units 7 can be provided in a building, for instance in a plurality of rooms of the building, such as the kitchen, living room, bedroom and/or bathroom. The operation of the local ventilation units is individually controllable. In figure 1 the ventilation unit 7 is mounted in the cavity 4.

[0040] Ventilation unit 7 has an air displacing unit with an air supply side and an air discharge side. The air supply side is connected to a space of the building, referred to hereinafter as the interior space O, via the inner wall 2. The air discharge side is connected to the outside environment via the outer wall 3. It will be apparent to the skilled person that the air discharge side can be arranged anywhere in the outer wall, such as for instance the reveal of a window. It is illustrated in the figure that a hole can be formed in the outer wall 3. This is optional. The outer side of the outer wall can then be finished with a grating at the position of the hole. Alternatively, it is possible to provide at the position of a window opening, door opening or gate opening in the wall an air channel from ventilation unit 7 to the reveal of the opening so that no hole need be provided in outer wall 3. Such an embodiment is illustrated in figure 5. When reference is made in the invention to an airflow through a wall, it is preferably only the inner wall 3 that is understood to be the wall. This is also the most relevant place structurally to refer to a wall passage since modern construction is finished with a foil or film sheet material at the inner wall in order to give the building an airtight finish. The wall passage then ensures that a controlled exchange of air into and out of the interior space can be provided. An example of an air displacing unit is a fan. Air is thus extracted from the interior space O by discharging air from interior space O to the air supply side of the air displacing unit. This is designated in figure 1 with arrow L.

[0041] Figure 1 shows a wall passage with a sound trap 100 according to an exemplary embodiment. The sound trap 100 is illustrated schematically and in section in order to show the operating principle. The blank arrows L thus represent an airflow flowing through the wall passage and the sound trap 100. It will be apparent here that the airflow L travels through a bend (not shown in this figure) at the position of the broken lines so as to flow from a direction transversely of the wall to a direction parallel to the wall and vice versa.

[0042] The wall passage is provided with a sound trap 100 between the air inlet and the air outlet. Sound trap 100 comprises a chamber 110 with a chamber air inlet 120 and a chamber air outlet 130. The air inlet of the wall passage can coincide with the chamber air inlet of sound trap 100. The chamber air inlet 120 of sound trap 100 can also form the air inlet of the wall passage. The air outlet of the wall passage can also coincide with the chamber air outlet 130 of sound trap 100. The chamber air outlet 130 of sound trap 100 can thus also form the air outlet 130 of the wall passage. Air inlet 120 is connected to the interior space O and air outlet 130 is connected to the air supply side of the air displacing device of ventilation unit 7. Chamber 110 forms a channel 140 which forms at least one segment of the channel of the wall passage, which is configured to demarcate an airflow between the air inlet and the air outlet. The channel 140 is thus configured to guide the air from air inlet 120 to air outlet 130. The airflow is realized by the air displacing device which creates an underpressure by drawing air in at the position of air outlet 130, so that a pressure difference prevails between air inlet 120 and air outlet 130. This pressure difference realizes an airflow from air inlet 120 to air outlet 130.

[0043] In the shown embodiment the chamber 110 further comprises a baffle 150 which forms the chamber and which, owing to the presence in the chamber, also forms the channel 140. The baffle is provided in chamber 110 so that a linear airflow P between chamber air inlet 120 and chamber air outlet 130 is prevented. Such a linear airflow P is shown in figure 1 for the purpose of elucidation, but is not possible in practice. Linear is understood to mean that the airflow is able to flow from chamber air inlet 120 to chamber air outlet 130 in one straight line, as would be the case if baffle 150 were not provided. In figure 1 chamber air inlet 120 and chamber air outlet 130 lie at the same height and baffle 150 lies between chamber air inlet 120 and chamber air outlet 130. The baffle 150 forces the airflow to travel through a bend which lies parallel to the wall. Hereby, the baffle forces the airflow to flow around baffle 150 and the baffle also forms an obstacle to sound produced by the air displacing unit. In other words, a sight line connection between chamber air inlet 120 and chamber air outlet 130 is broken. Without baffle 150, sound produced by the air displacing unit would be able to propagate from chamber air outlet 130 to chamber air inlet 120 in a straight line without any appreciable attenuation thereof. Because baffle 150 forms an obstacle to the sound, the sound trap damps the direct propagation of the sound waves. In this way the sound level related to the air displacing device and perceptible in the interior space is considerably lower than the actual sound level produced by the air displacing unit. On one hand the baffle 150 allows the sound waves produced by the air displacing device to be absorbed to a considerable extent in the chamber 110, for instance at the position of the chamber wall bounding channel 140. Baffle 150 itself will further also absorb sound. Baffle 150 allows diffusion of sound in that the sound waves are reflected at the position of the chamber wall of the chamber bounding the channel. Baffle 150 itself will also reflect, diffuse and/or absorb the sound waves. Because baffle 150 on one hand absorbs sound waves and on the other hand diffuses them, the sound waves are attenuated and the person present in the interior space will experience no or less noise nuisance. It is noted that the flow direction of the airflow L and a propagation direction of the sound produced by the air displacing unit are opposite in the illustrated situation. This will be further elucidated below. It is further noted here that the operating principle of the sound chamber will have the same effect when the airflow is reversed, i.e. from the fan in ventilation unit 7 to the interior space O.

[0044] The chamber 110 and the baffle 150 can be manufactured from the same material, for instance wood or plastic. An inward-directed wall of chamber 110, for instance a chamber wall bounding channel 140, and baffle 150 can be provided at least partially with a sound-absorbing layer. This improves the attenuation of the sound further. In the context of the application the terms "to attenuate" or "attenuation" are used synonymously with terms such as "to reduce", "to weaken", "to alleviate" or "to damp". The terms refer to acoustic damping as a measure of the energy loss of sound propagation in media, in the current context for instance air.

[0045] The sound-absorbing layer is preferably provided on at least a portion of the walls in the chamber 110 bounding the channel 140. Such a sound-absorbing layer can be made of a porous or soft material such as textile or foam. The texture and structure of the surface of the chamber wall and the surface of baffle 150 also affect the acoustic attenuation. A crease in the surface or woven or other non-flat texture can thus further attenuate the sound wave in that the sound wave is reflected in several reflection directions. Texture and material types can also be combined in order to further improve the attenuation. It is further noted that the sound-absorbing layer can be arranged selectively. The sound-absorbing layer can thus be arranged only at the position of the chamber air outlet 130, or over the whole surface of an inward-directed side of the channel. The sound-absorbing layer can further be arranged in several portions, which are each made individually from a determined material.

[0046] The preferred embodiment of the sound trap 100 shown in figure 1 comprises a baffle 150 which extends downward from an upper wall. Baffle 150 is mounted on the upper wall at the top, or baffle 150 lies substantially against the upper wall in order to substantially wholly prevent an airflow between the baffle 150 and the upper wall. Baffle 150 extends up to a predetermined distance from a lower wall of chamber 110. There is therefore an opening between a lower outer end of baffle 150 and the lower wall 112 of chamber 110. In this way a U-shaped air channel is formed, wherein the U-shape runs parallel to the inner wall and wherein the air channel has a bend of substantially 180 degrees around an underside of baffle 150 at the bottom of the U-shape. In this way the sound trap 100 has a first channel part which is oriented downward and extends from chamber air inlet 120 to the lower outer end of baffle 150, a second channel part which is oriented upward and extends from the lower outer end of baffle 150 to the chamber air outlet 130, and a third channel part in the form of a bend extending between the lower outer end of baffle 150 and the lower wall 112 of the chamber. It is noted that baffle 150 is arranged in accordance with the position of air inlet 120 and air outlet 130. When the position of the chamber air inlet and the chamber air outlet change, it will be apparent that the baffle 150 must be adjusted accordingly. In the figure the channel parts have substantially the same cross-sectional area, although this is not essential. The first channel part can thus be wider than the second channel part, and vice versa. Obstructions such as sound obstructions and/or guides can also be provided in the chamber, as will be further elucidated below.

[0047] It is clearly visible in figure 1 that the wall passage, and consequently the sound trap, are configured to facilitate an airflow at least partially through the inner wall 2, whereby for the wall passage the inner wall 2 is deemed the wall. The airflow flows primarily in a direction transversely of the wall. This is referred to as the primary direction because this is the most important direction functionally for having air flow from the one side to the other side of the wall. An orientation of the wall is not essential here, the wall can thus be an upright wall, as illustrated in figure 1. The wall can also have a lying orientation, for instance a ceiling wall. Although the airflow flows primarily in a direction transversely of the wall, the sound trap 100 prevents the airflow from flowing from air inlet 120 to air outlet 130 in a straight line. Sound trap 100 secondarily makes the airflow travel a distance in a direction parallel to the wall. A sound trap 100 with a wholly analogous operation can have a different orientation, wherein the baffle extends from a first wall to a position at a distance from a second wall.

[0048] Figure 1 shows that the baffle is preferably arranged to force the airflow along a single primary flow path. A primary flow path is a path or road along which the airflow mainly flows, in the figure a first segment of the primary flow path is directed downward. A second segment of the primary flow path has a bend of substantially 180 degrees, while a third segment of the primary flow path is directed upward. The three segments together form a U-shaped path or a U-shaped road. In other words, the primary flow path forms a U-bend between chamber air inlet 120 and chamber air outlet 130. By making the cross-sectional area of the channel large enough there is substantially no increase in the air resistance through the channel. It hereby requires hardly any more energy from the displacing unit to carry air through the channel, so that the sound production by the air displacing unit does not increase either.

[0049] Figure 1 further shows that a central flow axis of the airflow through the channel has a length greater than a linear distance between air inlet 120 and air outlet 130, preferably at least 1.5 times greater, more preferably at least 2 times greater. The central flow axis is illustrated in figure 1 by the blank arrows designated with reference letter L. The central flow axis of the airflow is a fictional axis which runs substantially through the centre of channel 140. Because the central flow axis has a length greater than the linear distance between air inlet 120 and air outlet 130, the sound trap attenuates sound waves in improved manner. Sound waves with a lower frequency, for instance 250 Hertz (Hz) or lower, are particularly attenuated in improved manner. Such low-frequency sound waves are more difficult to attenuate than high-frequency waves, at the least because the energy of the low-frequency sound wave dissipates less quickly. A linear distance could for instance be 10 cm. A length of the channel can however be for instance 20 cm or more, for instance 50 cm. The longer the channel, the more efficient the operation of sound trap 100 will be and, particularly, the more efficiently it will attenuate lower frequencies, at least within reasonable boundaries which are known to the skilled person and/or can be tested easily.

[0050] Figures 2A, 2B and 2C show further examples of a sound trap 100. The figures show an inner wall 2 in a front view frontally of the wall. The outer wall is not visible in the figures. As shown in figure 1, sound trap 100 comprises an upper wall 111 and a lower wall 112. Two side walls 113 extend between the upper and lower wall 111, 112. These side walls 113 extend upward in the inner wall 2. Channel 140 is further bounded by a first wall part 114 and a second wall part. The second wall part is not shown in figures 2A, 2B and 2C, yet still visible in figures 1 and 3, where the second wall part is designated with reference numeral 115. Side walls 113 lie substantially at right angles to the first wall part 114. Figures 2A, 2B and 2C show a channel 140 which extends substantially parallel to the inner wall. In this way the sound trap can secondarily make the airflow travel a distance in multiple directions lying substantially parallel to the wall 2.

[0051] Figures 2A, 2B and 2C show that the chamber air inlet 120 and the chamber air outlet 130 can be provided at different locations or that more than one inlet opening and/or outlet opening can be provided. This for instance allows the overall air inlet opening to be enlarged. Figure 2A thus for instance shows that two or more chamber air inlets 120 can be provided. One of the two chamber air inlets 120 is provided in the upper wall 111 of the chamber 110. Another of the two chamber air inlets is provided in a side wall 113 of the chamber 110. The chamber air inlets 120 as shown in figure 2 are particularly provided to be applied when the chamber is incorporated at least partially in the wall 2 via a frame. This frame is shown in figure 3. The chamber air inlets 120 open toward a space which lies between the relevant side wall 113 and/or upper wall 111 and the frame. This space forms a groove or niche in the wall 2 so that air is able to flow into and out of the space from the interior space O.

[0052] Figure 2A shows that the chamber air outlet 130 is provided in a first wall part 114. This first wall part 114 is situated on the side of the cavity and preferably lies in a plane parallel to the inner wall. The chamber air outlet can be positioned at the height of the chamber air inlet but on another side of baffle 150, this in order to prevent the airflow from being able to flow from the chamber air inlet to the chamber air outlet in a straight line. The first wall part (not shown in figures 2A, 2B and 2C) is preferably provided to lie opposite the chamber air outlet 130. In this way sound propagating through the chamber air outlet will thus hit the first wall part (not shown) almost immediately. An additional sound obstruction is thus provided in ingenious manner, this without reducing a passage opening of channel 140 so that the air resistance remains low. On one hand the sound waves produced by the air displacing unit hit the first wall part directly, whereby the sound waves are already attenuated early. On the other hand, the air pressure drop in the channel remains limited, whereby the air displacing unit remains functioning efficiently.

[0053] Figure 2B shows an example of the sound trap 100 with at least one sound obstruction 161, 162 in the channel, which obstruction 161, 162 is configured to at least partially damp or reflect sound. This improves the absorption and diffusion of sound waves in the channel further. Figure 2B shows that the sound trap 100 can be realized with two or more sound obstructions 161, 162. An example is thus shown with two sound obstructions 161, 162. A first sound obstruction 161 is provided at an outer end of baffle 150. It will be apparent to the skilled person that the sound obstruction 161 can also be situated at a different location in the channel, and can even be situated even at multiple locations. In this way the diffusion of sound waves is substantially further improved, particularly because more reflection of the sound in channel 140 takes place.

[0054] Figure 2B further shows that a second sound obstruction is provided against the lower wall. The second sound obstruction extends in the channel at the position of the bend. The second sound obstruction creates two recesses in the channel, in the figure on the left and on the right of sound obstruction 162. Tests have shown that the embodiment shown in figure 2B is particularly effective at attenuating sound propagation from chamber air outlet 130 to chamber air inlet 120. It is noted here that such a sound obstruction 162 can be produced in simple manner.

[0055] Figure 2C also shows a further example of a sound trap 100. In figure 2C a guide 170 is provided to divide the channel 140 into at least two sub-channels 141, 142 at the position of the bend, these sub-channels running parallel and defining a different length between the chamber air inlet 120 and the chamber air outlet 130. The guide 170 can be provided with a sound-absorbing textile, but guide 170 can also be manufactured from a hard material.

[0056] In each of the embodiments of figures 1 and 2A-2C the air inlet 120 is positioned offset relative to the chamber air outlet 130. Offset is understood to mean that, projected frontally onto the plane of inner wall 2, chamber air inlet 120 and chamber air outlet 130 do not coincide but lie at a mutual distance.

[0057] Figure 3 shows a perspective view of a further preferred embodiment of sound trap 100. The figure shows the sound trap in a preferred embodiment, wherein the sound trap is functionally connected to a local ventilation unit 7 as will be further described in figure 5. Figure 3 further shows a reveal finish 13. In figure 3 a wall passage according to the invention is provided to allow air to flow through the inner wall between the interior space on one side and the ventilation unit in the cavity wall on the other.

[0058] Figure 3 shows the sound trap 100 in an open state. Sound trap 100 is constructed with a fixed portion or frame 180 which can be incorporated at least partially in an inner wall. Frame 180 is connected via hinges 190 to a door part (110, 210). When this door part is closed by rotation of the door part toward frame 180, the chamber with the channel 140 demarcating the airflow is formed.

[0059] Sound trap 100 is provided with a door part with a first chamber 110 and a second chamber 210. The first chamber 110 is a chamber as already described at length above. Figure 3 further shows the second wall part 115 of chamber 110. In figure 3 the side walls 113, upper wall 111 and lower wall 112 are provided fixedly on the second wall part 115 and thus form the door part 110, 210. The skilled person will appreciate that this is just one embodiment, and that these walls can also be connected fixedly to the first wall part 114 such that the door is plate-like in its simplest form.

[0060] Figure 3 further shows that the baffle 150 need not necessarily be connected to the upper wall 111 and need not necessarily extend straight as shown in figures 2A, 2B and 2C. A similar, substantially U-shaped channel can thus also be formed in the manner shown in figure 3, for instance by extending substantially horizontally and inward from a side wall 113 and then forming a bend in the direction of the lower wall where the second sound obstruction 162 is formed.

[0061] In figure 3 the wall of the building is not shown in order to illustrate that the wall passage can comprise a frame 180. The frame 180 is configured to mount the sound trap in the wall. Frame 180 can here be provided such that at least one of the walls of the chamber is formed by the frame 180. In the shown embodiment the first wall part 114 of the chamber is formed by the frame 180. Frame 180 can also be provided to be functionally connected to a ventilation unit 7 in the cavity. Frame 180 allows sound trap 100 to be mounted robustly in the wall. The frame thus for instance allows the sound trap 100 to be mounted at least partially pivotally relative to the wall, preferably relative to the frame 180. For this purpose a hinge 190 can be provided between frame 180 and several walls of sound trap 100. In this way a door part of the sound trap is pivotable between an open position and a closed position.

[0062] Frame 180 preferably takes the form of a tray with a rear wall 114, which rear wall is placeable substantially parallel to the inner wall 2, and a plurality of upright walls with dimensions such that the tray has a substantially constant depth. The upright walls can be incorporated in an inner wall such that the edges of the upright walls lie in the plane of the inner wall. Provided in the rear wall is at least one opening 130 for allowing an airflow through inner wall 2. Sound trap 100, formed by a chamber, is formed such that it can be received substantially wholly in frame 180. When the outer wall of the chamber lies in line with the plane of the inner wall, a whole with an aesthetically pleasing finish is created. A space can be left here between at least a portion of walls 111, 113 and/or 112 and upright walls of frame 180 so that a groove or niche forms at the position of the surface of the inner wall. Air can flow into and out of the sound trap via this groove or niche, as further explained below. This paragraph describes a wall passage which is incorporated substantially wholly in an inner wall. It will be apparent to the skilled person that a wall passage can also be incorporated only partially, and that at least some of the components can protrude from the surface of the inner wall.

[0063] Figure 3 shows sound trap 100 in an open position. When sound trap 100 is in the closed position, the second wall part 115 functions as cover and the edges of the walls 113, 111, 112, 113 as seal between the first wall part 114 and the second wall part 115 so as to thus form the channel 140. In the shown embodiment the first wall part 114 is formed by the rear wall of frame 180. Owing to hinge 190, the chamber is thus always accessible, for instance for carrying out maintenance. This further also allows said ventilation unit to be reached so that for instance filters or functional elements, such as the air displacing unit, of the ventilation unit can be replaced, hardware and/or software updates can be performed, and so on. It will be apparent that when sound trap 100 is in the closed position, the second wall part 115 lies opposite and at a distance from the chamber air outlet 130. The distance between first wall part 114 and second wall part 115 corresponds with a height of the channel and with the height of the wall parts 113, 112, 111, as well as with the height of baffle 150. This height is at least 2 cm, preferably at least 4 cm, more preferably at least 6 cm, most preferably at least 8 cm, and is a maximum of 18 cm, preferably a maximum of 16 cm, more preferably a maximum of 14 cm and most preferably a maximum of 12 cm, and is for instance about 10 cm. In figure 3 the sound trap 100 is substantially beam-shaped. Upper wall 111, lower wall 112 and the two side walls 113 have substantially the same width here, for instance 10 cm. It will be apparent that the width of the walls 111, 112 and 113 is the dimension transversely of the wall. Compared to upper wall 111 and lower wall 112, the two side walls 113 have a greater length, for instance 75 cm compared to 40 cm. Owing to the construction of sound trap 100, the width of the walls 111, 112, 113 is substantially equal to the width of the channel 140 through which the air can flow. The airflow will hereby experience only a minimal resistance compared to other passages in which a considerable narrowing of the channel is provided. The specific construction as described in this text allows an air channel without any appreciable narrowed portions to be formed, so that an air displacing unit such as a fan need not work any harder than necessary.

[0064] The sound trap 100 shown in figure 3 comprises two air inlets 120. These air inlets are preferably provided with an air filter. The air inlets preferably have substantially the same dimensions. This allows the filters to be standardized on the basis of dimensions so that variations in replacement parts remain limited. The filters prevent dust, dirt and vermin from being able to enter channel 140. The same filters with the same dimensions can preferably also be used as outlet from the further second chamber 210 discussed below.

[0065] Sound trap 100 is further preferably provided to be incorporated at least partially in the inner wall, preferably using frame 180. At the position of chamber air inlet 120 the wall passage is configured to provide a space between sound trap 100 and frame 180. In other words, a portion of an outer side of walls 111 and 113 of sound trap 100 lies at a distance from an opposite wall of frame 180. The outer sides of the sound trap can be chamfered, wherein the thickness decreases toward the ventilation unit 7. Provided at the position of the inner side of inner wall 3 is a groove or niche which forms the space between frame 180 and the walls 111, 113 of the chamber. Via this niche or groove air is able to flow from the interior space, via the space into and/or out of the openings 120. The niche or groove can form a so-called shadow-casting recessed joint. In this way almost the whole sound trap can be concealed from view and the wall passage does not form any appreciable aesthetic disruption of the inner wall.

[0066] As shown in figure 3, the wall passage can comprise a second chamber 210 which forms part of a second wall passage for facilitating an opposite airflow through the wall. It is not essential for second chamber 210 to be provided with a baffle, because the sound which is produced is already attenuated partially yet considerably in the ventilation unit itself. Alternatively, second chamber 210 is also provided with a sound trap as described above. Further alternative embodiments wherein only the lower chamber is provided with a sound trap are also possible.

[0067] Figure 4 shows a schematic view of a wall passage with a sound trap 100 which is connected to a local ventilation unit 7. Similar to figure 1, the figure is unusual in that it shows different parts of the figure cut along different planes. This special representation allows an airflow to be shown in a direction transversely of the wall and in a direction parallel to the wall in a two-dimensional view. To the left of the left-hand vertical broken line, designated with arrow A, figure 4 thus shows a section transversely of the wall. Between the vertical broken lines, designated with arrow B, a section parallel to the wall is shown, and to the right of the right-hand vertical broken line a section transversely of the wall is shown. Sound trap 100 and local ventilation unit 7 are illustrated schematically and in section in order to show the operating principle. Sound trap 100 comprises a first chamber 110 and a second chamber 210. The first and second chamber 110, 210 have already been described at length above, in figure 4 the same or similar elements are designated with the same reference numerals as in figures 1, 2A, 2B, 2C and 3. The blank arrows L further represent an airflow flowing through the wall passage and the sound trap 100.

[0068] Figure 4 shows that a local ventilation unit 7 is connected to a wall passage comprising the sound trap 100 as described above. The local ventilation unit 7 comprises a heat exchanger (not shown) and a housing. The housing is configured to provide a first channel 20 for allowing air to flow from outside the building to inside, a second channel 30 for allowing air to flow from inside the building to outside, and a heat exchanger provision configured for a heat exchange between an airflow in the first channel 20 and an airflow in the second channel 30. The first channel of the local ventilation unit is also referred to as a first ventilation channel. The second channel of the local ventilation unit is also referred to as a second ventilation channel. The figure shows that first channel 20 extends between a suction opening 21 and an outlet opening 22 of first channel 20. Second channel 30 further extends between a suction opening 31 and an outlet opening 32. Figure 4 further shows that the local ventilation unit 7 is connected to the wall passage such that the chamber 110 of the wall passage forms an extension of at least one of the first and the second channel of the ventilation unit. Suction opening 31 of second channel 30 is thus preferably connected to the air outlet 130 of the first chamber and outlet opening 22 of first channel 20 is preferably connected to the air inlet 220 of the second chamber. In particular, first chamber 110 forms an extension of second channel 30, and the second chamber forms an extension of first channel 20. In order to supply air into the interior space O an air outlet 230 is provided in second chamber 210. It is preferred for the local ventilation unit to be connected to the wall passage such that the chamber 110 of sound trap 100 is positioned at the position of the air inlet 31 of the second channel 30 of ventilation unit 7.

[0069] Figure 4 further shows that ventilation unit 7 is preferably provided to be placed in a cavity of a building. The ventilation unit here preferably has a casing which is provided fixedly in the cavity and one or more functional modules which can be installed in and uninstalled from the casing. Provided fixedly is understood to mean that the casing cannot be removed without carrying out extensive work. Such extensive work is often at least partly destructive and requires for instance demolition of a part of a wall. Outlet opening 32 of second ventilation channel 30 and suction opening 21 of first ventilation channel 20 are located on a first side of ventilation unit 7, which preferably has an upright orientation. In mounted state the first side is preferably oriented parallel to a reveal. In practice the first side preferably lies substantially in line with the reveal. It will however also be apparent to the skilled person that the first side may lie parallel to and at a distance from the reveal, for instance 20 cm from the reveal.

[0070] Figure 5 shows a wall 1 of a building in which an opening is provided for fitting a window. Windows are typically provided in order to allow light to shine into a building. A window is an example of a functional opening in a building. Other functional openings comprise doors, gates, sliding windows and other similar openings. Functional openings are therefore typically provided in a wall 1 which has an inner wall 2 adjoining an interior space of the building, and has an outer wall 3 provided on an outer side of the building. In order to limit heat loss a cavity 4 is typically provided between inner wall 2 and outer wall 3. The cavity is defined by a space between inner wall 2 and outer wall 3, this space being filled with air or with an insulating material. A thermal barrier is hereby created between inner wall 2 and outer wall 3 so that energy can be better retained in the building. Reference is made in this description to inner wall 2, outer wall 3 and cavity 4, although it will be apparent here that this does not imply a traditional way of building. An outer wall 3 is defined as the outer shell of a building. The inner wall 2 is defined as the elements forming an inner shell of a building, wherein the inner shell is thermally insulated from the outer shell. The cavity 4 is defined as the zone and/or the elements thermally separating the inner shell and the outer shell at least partially from each other. The outer wall can be formed from stone, brick, metal, wood, plasterwork or other material suitable for forming an outer shell of a building. The cavity can be formed by insulating plates or foam fixedly connected to inner and/or outer wall. The cavity can alternatively be formed by a layer of air. The outer wall 3 is not necessarily self-supporting, and can be structurally connected to the inner wall via the cavity 4.

[0071] Recent legislation and modern techniques go a step further than creating a thermal barrier between outer wall 3 and inner wall 2 and also provide an airtight foil or film sheet material in wall 1 with the theoretical purpose of airtight enclosing of the interior space. Because of this airtight foil or film sheet material there is negligible, or at least no uncontrolled and appreciable exchange of air inside the building with air outside the building. This can further limit energy loss. This airtight foil or film sheet material has to be connected to the window when the window is placed in the opening.

[0072] It has been known for years to provide window profiles with which windows are constructed with a thermal barrier such that the profiles comprise an outer part and an inner part, wherein the outer part is configured to lie on the outside of the building and the inner part is configured to lie on the inner side of the building. Such window profiles are then mounted either with their outer part against outer wall 3 or with their inner part against inner wall 2. The thermal barrier provided between outer wall 3 and inner wall 2 can hereby be extended to the window. The thermal barrier can in this way take a continuous form so that cold bridges facilitating energy exchange from outside to inside the building, and vice versa, do not occur. It will be apparent here to the skilled person that, if both inner part and outer part of a window are placed on one of an outer wall 3 or inner wall 2, an undesirable heat exchange would be facilitated between either outer wall and inner part of the window profile or inner wall and outer part of the window profile so that a cold bridge occurs. The airtight foil or film sheet material provided in wall 1 is adhered against an edge of the window profile and connects airtightly against the window profile. A building with a window can be energy-optimized by providing a window in an opening of a building while making allowance for the aspects described above.

[0073] When an opening is provided in a wall 1, a so-called reveal is also formed. The reveal is defined as a straight, chamfered or profiled inner side of a window opening, gate opening or arch opening, which inner side preferably lies transversely or substantially transversely of the wall. The reveal is preferably always perpendicular to the wall. The reveal shows the thickness of inner wall 2, the thickness of cavity 4 and the thickness of outer wall 3. Figure 5 shows a portion of the upright reveal and a portion of the upper reveal of a window opening.

[0074] Figure 5 further shows a ventilation unit 7. The ventilation unit preferably forms part of a ventilation system and allows a forced controlled airflow from inside to outside and from outside to inside through wall 1. A plurality of such ventilation units can be placed in a plurality of respective rooms of a building in order to together form the ventilation system of the building. Because each ventilation unit of the ventilation system operates individually, the ventilation system can be explained in this description by describing the operation of one ventilation unit. It will be apparent here that, while a plurality of ventilation units can operate independently, the skilled person can couple them operationally in order to obtain a predetermined operational interaction between the different ventilation units in the ventilation system.

[0075] The ventilation unit of the ventilation system is constructed with a casing 5 and one or more modules which are provided with a heat exchanger for energy exchange between the inflowing and outflowing air. The ventilation system can be deemed a local ventilation system. This is because a plurality of such ventilation units 7 can be provided in a building, for instance at a plurality of window openings in a plurality of rooms of the building, the operation of which is controllable separately of each other.

[0076] Figure 5 shows the casing 5 of ventilation unit 7. Casing 5 is formed such that it can be provided fixedly in the cavity of a building. Provided fixedly is understood to mean that the casing 5 cannot be removed without carrying out extensive work. Such extensive work is often at least partly destructive and requires for instance demolition of a part of a wall. Casing 5 is for this purpose provided on an outer side with mounting means. These mounting means are preferably provided at the position of, i.e. in the vicinity of, the first side 8. Casing 5 has a first side 8 which preferably has an upright orientation. In mounted state the first side 8 is oriented parallel to the reveal. The first side 8 is also directed toward the reveal, i.e. of all sides, first side 8 lies closest to the reveal. In practice the first side 8 lies according to a first embodiment as shown in figures 1 and 2 substantially in line with the reveal or the first side 8 lies according to a second embodiment as shown in figures 3-5 parallel to and at a distance from the reveal, wherein the distance is preferably smaller than 15 cm, more preferably smaller than 10 cm. The first side 8 of casing 5 is provided with an opening 9. In the shown embodiment opening 9 extends over substantially the whole first side 8.

[0077] Casing 5 has a second side 10 configured to lie parallel to the wall. The second side 10 has a plurality of openings 35' and 37', further elucidated below. Second side 10 preferably lies against the inner wall 2 when the window is mounted in or at the inner wall, and preferably lies against the outer wall when the window is mounted in or at the outer wall. The wall passage according to the invention is provided to be connected to the openings 35' and 37' so as to allow air to flow through the wall in question, between the ventilation unit and the space. Hereby, one of the first side and second side will in each case face outward and another of the first side and second side will face inward. It has been discussed at length above that inner wall 2 can be provided with a passage when the second side 5 lies against the inner wall 2. The casing has a maximum outer dimension, measured transversely of the second side, of 30 cm, preferably 25 cm, more preferably 21 cm, in order to enable the whole casing to be incorporated in the wall. This means that the whole casing is situated between an inner shell and outer shell of the wall after being mounted in the wall.

[0078] Casing 5 further has a third side 11 which preferably forms the bottom side of casing 5. The third side 11 has a draining opening 12 for discharging condensation and other water that has entered casing 5.

[0079] Casing 5 is preferably beam-shaped. This means that opposite the first side lies a further first side with a surface area substantially equal to that of the first side. Opposite the second and the third side also lie respectively further second and further third sides, these having substantially the same surface areas as respectively the second and third side. The thus obtained beam-shaped casing can be incorporated in a cavity 4 in simple manner. The first side 8 is preferably smaller than the second side 10. First and second side 8 and 10 preferably have an upward orientation. The third side 11 is preferably smaller than the first side 8. The overall depth for functional modules 6 is hereby smaller than the overall height via first side 8. Third side 11 preferably extends in lying orientation as bottom surface.

[0080] Figure 5 shows schematically one or more functional modules 6 of a ventilation unit 7. The functional modules 6 can be incorporated in casing 5 via the opening 9 in first side 8. The functional modules 6 can also be dismantled from casing 5 via the opening 9 in first side 8. For the sake of simplicity, figure 5 shows one functional module comprising all functions. The functional modules 6 preferably comprise a first housing part and the second housing part with therein one or more of the sensors, ventilators and heat exchanger. Casing 5 is for this purpose formed with dimensions corresponding with a mounted assembly of first housing part and second housing part, such that in mounted state the housing parts can be installed in and uninstalled from the casing via first side 8. In mounted state the first site 8 of casing 5 will here substantially coincide with the above described first side A of the housing assembly.

[0081] Heat exchanger 24 is of the air-air type, so that a heat exchange is possible between a first and a second airflow. Heat exchanger 24 is configured for this purpose to allow crosswise flow of the airflows relative to each other in a manner such that heat exchange between the flows is optimized. Air-air heat exchangers are known and the details of this heat exchanger are therefore not described in further detail in this description. The heat exchanger can be configured to exchange only heat, but can also be a so-called recuperator. A recuperator not only exchanges heat, but also recuperates moisture. This is also referred to as an enthalpy heat exchanger.

[0082] The second channel 30 starts at a second suction opening 31 provided in a second side of the ventilation unit which, when ventilation unit 7 has been incorporated in the wall, adjoins an interior space of the building. The first outlet opening 22 is provided for allowing outflow of air to the interior space from outside to inside via first channel 20. When the housing assembly is mounted in casing 5, second suction opening 31 is aligned with opening 35' and first outlet opening 22 is aligned with opening 37'.

[0083] Ventilation unit 7 further optionally comprises a fifth opening 36 which is preferably formed in the same side as second opening 35 and third opening 37. This fifth opening 36 is optionally positioned (not shown) at the location of a filter for filtering the inflowing outside air. An advantage hereof is that this filter is accessible via the fifth opening 36. Fifth opening 36 is preferably positioned between second opening 35 and third opening 37. As a result of this positioning of the openings, in particular the positioning of fifth opening 36, all filters present in ventilation unit 7, more specifically the filter for filtering the air flowing from inside to outside and the filter provided for filtering the air flowing from outside to inside, can be replaced via inner wall 2. The filter preferably comprises a carbon filter, more preferably an active carbon filter, which cleans incoming air. This makes maintenance of ventilation unit 7 extremely simple.

[0084] Figure 5 shows that suction opening 21 and outlet opening 32 are located on a first side A of casing 5 when the housing assembly is incorporated in casing 5.

[0085] Figure 5 further shows a reveal finish 13 for the upright reveal and a finish 14 for the upper reveal. When the reveal finish is mounted, a segment of the reveal finish 13 comes to lie in front of the opening 9 in first side 8 of casing 5 and in front of the first side A of the housing assembly. This segment therefore functions as cover 15 for the opening 9 in first side 8. It is particularly when airflow openings of the functional modules 6 open on the first side 8 that the cover 15 is provided with perforations 16 to allow the airflow through cover 15.

[0086] Figure 6 shows a cross-section of a wall at the position of the ventilation unit. Figure 6 thereby shows the above described components including the outer wall 3, the cavity 4 with insulation 17, the inner wall 2, the casing 5 and the lateral guide 19 of a screen device. Figure 6 further shows particularly that, at the position of casing 5, a zone 17' is provided between the inner wall 2' and casing 5. The zone 17' forms a barrier between casing 5 and inner wall 2. Figure 6 further shows that a window 53 is provided at the position of an inner wall 2. This window 53 is connected via a thermal plate 54 to the inner wall in order to prevent cold bridges. The zone 17' and the thermal plate 54 are deemed part of the inner shell of the building since zone 17' and thermal plate 54 at least partially define the form and position of inner wall 2. In the embodiment as shown in figure 6 the whole casing 5 will therefore also fall between the outer shell 3 and the inner shell 2, 2', 17' and 54. Because the housing assembly is also preferably formed from heat-insulating material, the housing assembly of the ventilation unit will also have an insulating effect.

[0087] A zone 17' can be provided between casing 5 and inner wall 2 in two ways. The figure shows an embodiment wherein inner wall 2 has been made narrower at the position of the casing so that the zone 17' fits between the narrower inner wall and the casing 5 (narrower as seen in a direction transversely of the wall). In this embodiment the casing 5 can be embodied with the same width as cavity 4, as seen in a direction transversely of the wall. In an alternative embodiment casing 5 is narrower than cavity 4 and the difference in width is filled up with the zone 17'. There is in any case preferably an overlap of zone 17' and insulating material 17 in order to prevent cold bridges and to obtain a good insulation. A combination of the above described embodiments is of course also possible. The wall passage 100 according to the invention is shown conceptually in the figure and is provided to allow air to flow from the interior space to the casing 5, through inner wall 2.

[0088] Because the housing assembly is preferably also formed from heat-insulating material, it will also be possible to use the space in the inner wall which is filled up by zone 17' in figure 6, this without any appreciable heat-insulating effect, to provide the above described sound trap 100. The piece of inner wall 2', and optionally also a part of the zone 17', can thus be replaced integrally by the frame 180 with sound trap 100 as shown in figure 3, or by a variant thereof, in order to further optimize the throughfeed for air through inner wall 2. The advantage of working with a wall passage, wherein a piece of wall is effectively provided which lies between the outlet openings in the space on one side and the ventilation unit outside the space on the other, relates to airtight finishing of the space. Because the wall continues all the way up to the window, this wall can be provided with an airtight and damp-proof and/or breathable foil or film sheet material, which greatly improves the energy performance of the space. A passage is then provided through this wall in order to supply and/or discharge air in controlled manner.

[0089] The skilled person will appreciate on the basis of the above description that the invention can be embodied in different ways and on the basis of different principles. The invention is not limited to the above described embodiments. The above described embodiments and the figures are purely illustrative and serve only to increase understanding of the invention. The invention will not therefore be limited to the embodiments described herein, but is defined in the claims.

Claims

1. A wall passage provided to be incorporated at least partially in a wall of a building and suitable for connection to an air displacing unit, the wall passage comprising an air inlet and an air outlet between which is situated a channel configured to facilitate an airflow at least partially through the wall and between the air inlet and the air outlet, which airflow is directed primarily in a direction transversely of the wall, characterized in that provided between the air inlet and the air outlet is a sound trap which takes the form of a chamber with a chamber air inlet and a chamber air outlet between which at least a segment of the channel is situated, wherein the segment of the channel secondarily guides the airflow in a direction substantially parallel to the wall and wherein the chamber is formed such that said segment of the channel has a substantially two-dimensional bend which lies parallel to the wall in order to prevent a linear airflow from the chamber air inlet to the chamber air outlet and so damp propagation of sound through the chamber.

2. The wall passage according to the foregoing claim, wherein a central flow axis of the airflow in the chamber lies substantially wholly in a plane lying parallel to the wall.

3. The wall passage according to the foregoing claim, wherein the central flow axis of the airflow has a length greater than a linear distance between the air inlet and the air outlet, preferably at least 1.5 times greater, more preferably at least 2 times greater.

4. The wall passage according to any one of the foregoing claims, wherein the substantially two-dimensional bend is almost 180 degrees so that the segment of the channel extends substantially in a U-shape.

5. The wall passage according to any one of the foregoing claims, wherein the chamber comprises a baffle for preventing the linear airflow in the plane.

6. The wall passage according to the foregoing claim, wherein the substantially two-dimensional bend lies around the baffle.

7. The wall passage according to any one of the foregoing claims, further comprising a frame which is configured to mount the sound trap in the wall.

8. The wall passage according to the foregoing claim, wherein the chamber is connected to the frame at least partially via a hinge such that the chamber has an open state and a closed state.

9. The wall passage according to the foregoing claim, wherein one of the chamber air inlet and the chamber air outlet is provided at the position of a space between the frame and the chamber, such that air is able to flow from the space to the chamber air inlet or from the chamber air outlet to the space.

10. The wall passage according to the foregoing claim, wherein the space is formed by a niche or groove in the wall of the building.

11. The wall passage according to any one of the foregoing claims, wherein an inner wall of the channel is provided at least partially with a sound-absorbing layer.

12. The wall passage according to any one of the foregoing claims, further comprising a second chamber adjacent to and separate from the first chamber, which second chamber is provided to facilitate a second airflow through the wall between a second air inlet and a second air outlet.

13. Local ventilation unit connected to a wall passage according to any one of the foregoing claims, the ventilation unit comprising

- a heat exchanger and

- a housing configured to facilitate a first channel for allowing air to flow from outside the building to inside, a second channel for allowing air to flow from inside the building to outside, and a heat exchanger provision configured for a heat exchange between an airflow in the first channel and an airflow in the second channel;

wherein the local ventilation unit is connected to the wall passage such that the chamber of the wall passage forms an extension of at least one of the first and the second channel of the ventilation unit.

Drawing