Ventilation system for installation in a building wall and building equipped therewith

Abstract

Ventilation system for installation in a building wall, comprising a housing with a heat exchanger and at least a first inlet duct and a second inlet duct, a first outlet duct and a second outlet duct, a first air inlet, a second air inlet, a first air outlet and a second air outlet, wherein: on a first side of the heat exchanger: - the first inlet duct connects the first air inlet to a first inlet side of the heat exchanger and the second outlet duct connects the second air outlet to a second outlet side of the heat exchanger, and on a second side of the heat exchanger: - the second inlet channel connects the second air inlet to a second inlet side of the heat exchanger and the first outlet channel connects a first outlet side of the heat exchanger to the first air outlet; wherein, within the heat exchanger, the first inlet side is connected to the first outlet side by a first set of flow channels and the second inlet side is connected to the second outlet side by a second set of flow channels, so that during use, heat can be exchanged between air in the first set of flow channels and air in the second set of flow channels, wherein at least one first fan is provided in at least one of the first inlet channel and the first outlet channel, and at least one second fan is provided in at least one of the second inlet channel and the second outlet channel.

Description

[0001] The invention relates to ventilation systems for installation in a building wall.

[0002] In buildings, such as residential or office buildings, ventilation is important to maintain a comfortable and healthy climate inside the building. For this purpose, it is known to equip a building with a duct system that distributes the air flowing into the building to various rooms inside the building and removes the air from these rooms. A central fan and heat exchanger connected to the duct system can be provided to extract heat from the exhaust air and transfer this heat to the incoming air, making the system more environmentally efficient. However, such a system is expensive, requires a relatively large amount of space and infrastructure within the building, and is difficult to install in existing buildings.

[0003] To overcome some of the problems of this known system, it has been proposed to equip rooms within a building with individual ventilation systems installed in an external wall of such a room, allowing outside air to be drawn directly into the room and inside air to be extracted from the room and expelled outside the building. Such systems can be passive, such as ventilation grilles in a door or window, or in a wall, but this makes the system environmentally unfriendly, as heat is expelled along with the inside air during the heating season. Furthermore, such a ventilation system relies entirely on pressure differences across the ventilation grille to generate airflow.To overcome this disadvantage, the use of active systems is known. These systems utilize a fan to actively generate airflow, while a heat exchanger is used to capture energy from the expelled air and transfer this energy to the incoming air. If the outside temperature is higher than the inside temperature, the opposite will occur.

[0004] A well-known active ventilation system is a push-pull system, known, for example, under the brand name Lunos and described, for example, in US Pat. No. 9,845,959. In such a system, two separate, spaced-apart openings are provided in an exterior wall of a room. For each opening, a fan is provided, as well as a ceramic heat exchanger block with a plurality of channels extending through it, wherein the channels all have a relatively low flow resistance. Therefore, axial fans can be used, which are relatively inexpensive but have only limited pressure generation capacity. During use, each of the two fans is driven alternately in a first direction and in an opposite second direction, so that the fan blows outside air into the room in the first direction and air out of the room in the second direction.By controlling the fans so that a first of the two fans is rotated in the first direction while the second fan is driven in the second direction and vice versa, an air flow can be maintained in the room.

[0005] In such a push-pull system, the air flowing out of the room during a first period passes through the channels in the corresponding ceramic block and heats the block for the duration of the first period by transferring heat energy to the block. The fan is then stopped and its direction of rotation is reversed, after which outside air is forced through the channels in the block for a second period. This outside air is heated by the heat stored in the block while simultaneously cooling the block. At the end of the second period, the fan is stopped again and its direction of rotation is reversed to start a new first period. The first period and the second period are of equal length.At the same time, the other fan is operated with the same regime but in opposite phase, so that the first fan is driven in the first direction, while the second fan is driven in the second direction and vice versa.

[0006] Push-pull ventilation systems have the advantage of being easy to install and relatively inexpensive. However, a disadvantage of these systems is that they use axial fans, which are inefficient. Relatively low wind pressure acting on the ventilation system from the outside of a building prevents adequate air expulsion from the building. Furthermore, such wind pressure can blow cold outside air directly into the room. Furthermore, such systems are relatively noisy, especially at higher fan speeds. A user can adjust the fan speed using a wall-mounted control panel, for example. While increasing the fan speed increases airflow, it also undesirably increases noise levels.Another disadvantage of these push-pull systems is that the fans must be stopped periodically—for example, every minute—to reverse their rotation direction. This, in turn, increases the noise level and reduces the effective ventilation time and thus the efficiency of the system. Due, among other things, to the low resistance of the ducts and the limited time available for heat transfer between the block and the airflow, the heat transfer efficiency is also relatively low, for example, 40% or less. Another disadvantage of these systems is that the refreshment rate of the indoor air by outdoor air is relatively low—for example, 50% or less—resulting in less favorable indoor air quality.

[0007] WO99 / 13284 discloses a ventilation system comprising a tubular casing with an inlet duct and an outlet duct, wherein a plate heat exchanger is provided for exchanging heat between air flowing through the inlet duct and air flowing through the outlet duct. It features upper and lower impellers driven simultaneously by a single motor, with the motor and impellers located at one end of the casing, which is located outside the building to be ventilated. The impellers are driven at the same speed, meaning that pressure differences in the ducts—for example, due to wind pressure on the building—lead to a significant imbalance. A plate heat exchanger has a much lower buffer capacity than a heat exchanger according to US9,845,959, but the responsiveness for heat exchange is still relatively low.

[0008] DE4440436 and its equivalent SE507252 disclose a ventilation system with a tubular part penetrating a wall and an impeller system comprising an electric motor driving two impellers, each of these impellers extending into one of two ducts provided in the same tubular part. A heat exchanger is mounted on the outside of the wall and is connected to the tubular part and the two ducts to exchange heat between the air streams flowing through the two ducts and driven by the impellers. The heat exchanger is a plate heat exchanger, as is known from the prior art. In these documents, JP Sho 50-2950 is disclosed as prior art, which has two separate impellers arranged side by side in an inlet duct and an outlet duct, respectively, which requires a relatively large diameter of the opening in the wall.Again, a plate heat exchanger is provided essentially outside the wall, where the sensitivity for heat exchange is still relatively low.

[0009] These plate heat exchangers also have relatively low efficiency and performance because the stacked plates define channels for incoming and outgoing air. If the channels are too thin, air resistance becomes excessive, while the length of the plate in the flow direction is limited by the width of the wall. Otherwise, the plate, and thus the heat exchanger—as disclosed in the referenced prior art—must extend a considerable distance outside the wall, and the cross-section of the channel must be large. Furthermore, the materials used for the plate generally have a low heat transfer coefficient.

[0010] The object of the present invention is to provide a ventilation system for installation in a building wall, wherein at least one of the disadvantages of a push-pull system as disclosed is at least partially overcome. In this description, "in a wall" is to be understood as including at least "partially in a wall" and "partially on a wall", wherein a wall can be any partition between an interior and an exterior space. One object of the present invention may be to provide a ventilation system for installation in a building wall as an alternative to a push-pull system. One object of the present invention may be to provide a ventilation system for installation in a building wall which, for example, is more efficient with regard to energy consumption and / or heat transfer than known push-pull systems or the other described systems according to the prior art.One object of the present disclosure may be to provide a ventilation system for installation in a building wall, which has a relatively low noise level during use. One object of the present disclosure may be to provide a ventilation system for carrying out a method for ventilating a room in a building. One object of the present disclosure may be to provide a more compact heat exchanger that requires fewer and smaller openings in a wall than the described systems according to the prior art.

[0011] At least one of these objects and other objects can be achieved at least in part with a ventilation system and / or method according to the disclosure.

[0012] According to one aspect, a ventilation system for installation in a building wall may comprise a housing with a heat exchanger and at least a first inlet duct and a second inlet duct, a first outlet duct and a second outlet duct, a first air inlet, a second air inlet, a first air outlet, and a second air outlet. On a first side of the heat exchanger, the first inlet duct connects the first air inlet to a first inlet side of the heat exchanger, and the second outlet duct connects the second air outlet to a second outlet side of the heat exchanger. On a second side of the heat exchanger, the second inlet duct connects the second air inlet to a second inlet side of the heat exchanger, and the first outlet duct connects a first outlet side of the heat exchanger to the first air outlet.Within the heat exchanger, the first inlet side is connected to the first outlet side by a first set of flow channels, and the second inlet side is connected to the second outlet side by a second set of flow channels, such that, during use, heat can be exchanged between air in the first set of flow channels and air in the second set of flow channels. At least one first fan is provided in at least one of the first inlet channel and the first outlet channel, and at least one second fan is provided in at least one of the second inlet channel and the second outlet channel.

[0013] In a system according to the disclosure, the heat exchanger can simultaneously generate counter-rotating airflows, resulting in active heat transfer, which increases the efficiency of the system. With a system according to the disclosure, the air in the room can be refreshed up to 100% of the time, and heat can be exchanged between the outside air introduced into the room and the inside air expelled from the room.

[0014] In preferred embodiments, a controller is provided that is designed to operate the first fan and the second fan separately, preferably independently of each other. The first and second fans are preferably modulating fans. This allows the speed of the fans to be regulated to increase or decrease the airflow through the corresponding ducts.

[0015] Preferably, a system according to the disclosure uses a wire heat exchanger—preferably as described. The wire heat exchanger has very little to no buffer capacity. Thus, in the present application, all of the heat absorbed in one of the ducts can be and is transferred directly—completely or at least substantially without delay—to the air flowing through the other duct. This enables precise balancing of airflows and thus optimization of heat absorption and heat transfer, resulting in a system with high efficiency. Such efficiency can be achieved by appropriate adjustments of the fan speed(s), even when, for example, high wind pressure, also known as wind load on the walls of a building, exists on an inlet side outside the building. In this way, the efficiency of the system can be maintained.It is understood that, for example, a similar level of efficiency can be achieved for the emission of CO, CO2, NOx, moisture or the like by using suitable, in particular dedicated or combined sensors for such components.

[0016] It is further understood that sensors may be provided for the same or a similar purpose - with the same or similar effect - in any of the disclosed or described embodiments.

[0017] In preferred embodiments, sensors are provided in the ducts, which are connected to a system controller designed to operate the fans in dependence on at least the signals received from the sensors in order to balance the air flow through the ducts. Preferably, the sensors are temperature sensors or at least comprise temperature sensors with which a temperature increase or decrease across ducts in which the sensors are provided can be measured. In this way, it can be determined whether a temperature increase in one of the ducts cq is substantially equal to a temperature decrease in the other of the ducts cq, which indicates substantially complete heat transfer in the heat exchanger.If the temperature increase in one of the ducts does not match the temperature decrease in the other duct, the speed of at least one of the first and second fans can be adjusted to balance the air flows and thus optimize heat transfer.

[0018] In advantageous embodiments, the housing comprises a tubular portion, wherein at least a portion of the first inlet channel and a portion of the second outlet channel extend through the tubular portion in a juxtaposed arrangement. The tubular portion preferably has a substantially circular cross-section.

[0019] In such embodiments, only one hole needs to be drilled through an exterior wall to attach the tubular section.

[0020] It is understood that in the disclosure, a wall is to be understood as including, for example, doors and windows. A ventilation system according to the disclosure can, for example, be mounted in a door or window.

[0021] A heat exchanger for use in a system according to the disclosure is preferably a once-through heat exchanger comprising the first set of flow channels and the second set of flow channels, wherein the first and second flow channels are separated from each other. The heat exchanger further comprises heat-conducting metal wire elements extending across channels of the first set of flow channels and channels of the second set of flow channels, such that, during use, heat is transferred from the air flowing through the first set of flow channels via the metal wire elements to the air flowing through the second set of flow channels, or vice versa. Such a heat exchanger may also be referred to as a wire heat exchanger.

[0022] Particularly preferably, the wire elements extend in their longitudinal axis substantially parallel to one another at least partially over one of the first and second air inlet sides and one of the first and second air outlet sides of the heat exchanger, wherein the distance perpendicular to the longitudinal axis between adjacent wire elements is between 2 times and 20 times the largest cross-sectional dimension of the wire elements.

[0023] In embodiments, a heat exchanger of a ventilation system according to the disclosure has a main plane with a longitudinal direction and a width direction preferably running perpendicular to the longitudinal direction, wherein on a first side of the heat exchanger, the first inlet side is provided on a first side of the main plane and the second outlet side is provided on an opposite second side of the main plane. On an opposite second side of the heat exchanger, the second inlet side is provided on the first side of the main plane and the first outlet side is provided on the second side of the main plane, wherein the longitudinal direction of the main plane runs substantially parallel to a longitudinal axis of a housing section in which the heat exchanger is provided.

[0024] Such an embodiment enables a compact design that can provide effective heat transfer while the system is easy to install.

[0025] In a system according to the disclosure, at least one of the fans may be an axial fan. In such an embodiment, preferably both the first and second fans are axial fans. In alternative embodiments, at least one of the fans may be a centrifugal fan. In such an embodiment, preferably both the first and second fans are centrifugal fans.

[0026] In embodiments, the housing may be substantially tubular and preferably have a substantially circular cross-section and a longitudinal direction, wherein the heat exchanger is provided in the housing in a sealing manner against an inner surface of the housing and divides an internal volume of the housing into at least one outer end portion and an inner end portion. At the outer end portion, a first partition wall extends from the heat exchanger in the longitudinal direction and divides the outer end portion into the first inlet channel and the second outlet channel, wherein the inner end portion comprises the second inlet channel and the first outlet channel.

[0027] Such designs are compact and require only a single opening in the wall for installation. They are easy to manufacture, maintain, and operate, and are highly energy efficient, while the fans can operate relatively quietly.

[0028] In embodiments, a system according to the disclosure is suitable for carrying out a method for ventilating a room in a building, wherein a ventilation system is provided in a wall of the room, comprising a housing with a heat exchanger and at least a first inlet duct and a second inlet duct, a first outlet duct and a second outlet duct, a first air inlet, a second air inlet, a first air outlet and a second air outlet, wherein on a first side of the heat exchanger, the first inlet duct connects the first air inlet to a first inlet side of the heat exchanger and the second outlet duct connects the second air outlet to a second outlet side of the heat exchanger.On a second side of the heat exchanger, the second inlet duct connects the second air inlet to a second inlet side of the heat exchanger, and the first outlet duct connects a first outlet side of the heat exchanger to the first air outlet. Within the heat exchanger, the first inlet side is connected to the first outlet side by a first set of flow ducts, and the second inlet side is connected to the second outlet side by a second set of flow ducts, such that, during use, heat can be exchanged between air in the first set of flow ducts and air in the second set of flow ducts. At least one first fan is provided in at least one of the first inlet duct and the first outlet duct, and at least one second fan is provided in at least one of the second inlet duct and the second outlet duct.The first fan and the second fan are each driven in a single direction so that a first air flow through the heat exchanger is obtained between the first inlet and the first outlet and a second air flow opposite to the first air flow is obtained between the second inlet and the second outlet.

[0029] In preferred embodiments, the speed of at least one of the two fans, preferably both, can be controlled—particularly by modulation—to balance the airflow through the inlet duct and the outlet duct to optimize heat transfer. Preferably, the speed is controlled by a controller based on a temperature increase measured in a first of the ducts and a temperature decrease measured in the other, second, duct.

[0030] For a better understanding of the disclosure, various embodiments of ventilation systems and heat exchangers for use in such systems, as well as aspects thereof, are described below with reference to the drawings, in which: the Fig. 1 shows in cross section a general configuration of embodiments of a system according to the disclosure; the Fig. 2 shows in cross section an embodiment of a system according to the disclosure; the Fig. 3 shows in cross section an alternative embodiment of a system according to the disclosure; the Fig. 4 and Fig. 5 perspective views of an embodiment of a system according to the disclosure, the Fig. 6 is a side sectional view of a fine wire heat exchanger for use in a system according to the disclosure; the Fig. 6A and Fig. 6B Sectional views of a heat exchanger of the Fig. 6 along lines VI A - VI A or VI B - VI B in the Fig. 6; the Fig. 7 is a perspective, partially exploded view of another embodiment of a system according to the disclosure with the housing partially broken away; the Fig. 8 shows in cross section another embodiment of a system according to the disclosure with separate inlet and outlet through a wall; the Fig. 8A in perspective view a system according to Fig. 8, with the cover and heat exchanger removed; and the Fig. 8B the system of Fig. 8 and Fig. 8A, with the heat exchanger, without cover, in place; the Fig. 9 is a cross-sectional view of a general configuration of embodiments of a system according to the disclosure, similar to that shown in Fig. 1, wherein a controller and sensors are shown; and the Fig. 10 is a comparison diagram of various fan types and heat exchangers according to the prior art and according to the present disclosure.

[0031] The embodiments illustrated in the drawings and described in the following description are shown and described only as examples to facilitate understanding of the claimed invention and should not be considered as limiting the scope of the disclosure in any way or form. In the drawings, like or similar parts are designated by like or similar reference numerals.

[0032] The disclosure is directed to ventilation systems for installation in a building wall, the system comprising a housing with a heat exchanger and at least a first inlet duct and a second inlet duct, a first outlet duct and a second outlet duct, a first air inlet, a second air inlet, a first air outlet, and a second air outlet. In this description, "in a wall" is understood to mean that at least part of the system extends in and / or through a wall, while part of the system may be attached to a wall or spaced from that wall. In this description, a wall is understood to mean at least a partition between a room and an adjacent space, for example, a partition between an interior and an exterior space. A wall may, for example, be a brick, wood, and / or concrete partition, a door, or a window between a room inside a building and the exterior of the building.In this description, a duct is understood to mean at least any passage of any axial length and any diameter, which, for example, fluidically connects one room or area or part of a system to another room or area or part of the same or another system. In this description, heat exchange is understood to mean at least the exchange of heat between two air flows, wherein heat can be transferred from a relatively warm first flow to a relatively cool second flow, wherein the first flow can be either a flow into a building or a flow out of the building, wherein the second flow is opposite to the first flow.

[0033] On a first side of the heat exchanger, the first inlet duct connects the first air inlet to a first inlet side of the heat exchanger, and the second outlet duct connects the second air outlet to a second outlet side of the heat exchanger. On a second side of the heat exchanger, the second inlet duct connects the second air inlet to a second inlet side of the heat exchanger, and the first outlet duct connects a first outlet side of the heat exchanger to the first air outlet.

[0034] In this description, a first side and a second side are understood to mean at least spaced-apart sides of a system, such as, but not limited to, opposite sides of a system, or sides facing in different directions, such as, but not limited to, opposite directions. For example, in this description, a first side may be a side of the system facing toward an interior of a building, and the second side may be a side of the system facing outward from the building, for example, into an outdoor space, or vice versa.

[0035] Within the heat exchanger, the first inlet side is connected to the first outlet side by a first set of flow channels and the second inlet side is connected to the second outlet side by a second set of flow channels such that, during use, heat can be exchanged between air in the first set of flow channels and air in the second set of flow channels.

[0036] According to the disclosure, at least one first fan is provided in at least one of the first inlet duct and the first outlet duct, and at least one second fan is provided in at least one of the second inlet duct and the second outlet duct. The fans can direct air in opposite directions through the system, in particular through the heat exchanger, thus providing a counterflow system that enables highly efficient heat exchange. Air directed through the system in a first direction can thereby exchange heat with air flowing in the opposite direction.

[0037] For example, air that is led from an outside space into a space inside a building can be heated by air that flows out of the building from such an interior space of the building.

[0038] For further understanding, this disclosure describes methods that may be performed with embodiments of systems according to the disclosure.

[0039] The Fig. 1 shows schematically in cross section a system 1 according to the disclosure, or at least a corresponding part thereof. Fig. 1 shows a housing 2 with a heat exchanger 3 and at least a first inlet channel 4 and a second inlet channel 5, a first outlet channel 6 and a second outlet channel 7, a first air inlet 8, a second air inlet 9, a first air outlet 10 and a second air outlet 11.

[0040] On a first side 12 of the heat exchanger 3, the first inlet duct 4 connects the first air inlet 8 to a first inlet side 13 of the heat exchanger 3, and the second outlet duct 7 connects the second air outlet 11 to a second outlet side 14 of the heat exchanger 3. On a second side 15 of the heat exchanger 3, the second inlet duct 5 connects the second air inlet 9 to a second inlet side 16 of the heat exchanger 3, and the first outlet duct 6 connects a first outlet side 17 of the heat exchanger to the first air outlet 10.

[0041] In the embodiments shown, the first side 12 and the second side 15 are depicted as opposite sides of the system, so that during use, a first side 12 may face an external space "OUTSIDE" of a building B, while the opposite second side 15 may face an "INSIDE" space within the building B, or vice versa. The first and second sides 12, 15 are depicted directly opposite each other, but they could also be angled relative to each other - for example, but not limited to, using a curved or angled housing or by providing the inlets and outlets 8, 9, 10, and / or 11 in one side of the housing 2.

[0042] Within the heat exchanger 3, the first inlet side 13 is connected to the first outlet side 17 by a first set of flow channels 18. The second inlet side 16 is connected to the second outlet side 14 by a second set of flow channels 19. Thus, as will be explained further, during use, heat can be exchanged between the air in the first set of flow channels 18, represented by the first arrow 20, and the air in the second set of flow channels 19, represented by the second arrow 21, which points in the opposite flow direction of the first arrow 20.

[0043] At least one first fan 22 is provided in at least one of the first inlet duct 4 and the first outlet duct 6, and at least one second fan 23 is provided in at least one of the second inlet duct 5 and the second outlet duct 7. In the embodiment of the Fig. 1, the first fan 22 is provided in the first inlet duct 4 and the second fan 23 is provided in the second outlet duct 7.

[0044] In the embodiment of the Fig. 1, the first and second fans 22, 23 are both depicted as centrifugal fans, which have a relatively high performance, particularly compared to a similarly sized axial fan with similar energy consumption. Centrifugal fans are also advantageous over axial fans in that they can generate a relatively high pressure compared to a similarly sized and similarly powered axial fan. This is particularly true for bidirectional axial fans, such as those used in prior art push-pull systems. This is important because, during use, the wind in the outdoor space "OUTSIDE" acts on the outward-facing side, in particular on the second air outlet 11 of the system, thus generating backpressure on the corresponding fan, in particular on the second fan 23.It has been found that this can be more easily overcome by using a radial or centrifugal fan. However, it should be understood that one or both of the fans may also be axial fans, particularly single-direction axial fans. As will be explained further, centrifugal fans may also be used in embodiments.

[0045] In the Fig. 1, two fans 22A, 23A are shown in dashed lines, which could be provided instead of the first and / or the second fan 22, 23 or in addition to the first and the second fan 22, 23.

[0046] As in the Fig. 1, the first set of channels 18 and the second set of channels 19 preferably intersect such that the first air stream 20 and the second air stream 21 flow past each other such that heat can be exchanged between these air streams. For example, air 20 flowing in from the outdoor space "OUTSIDE" can be heated by heat from air 21 flowing from an indoor space "INSIDE" to the outdoor space "OUTSIDE". A heat exchanger 3 for use in a system 1 according to the disclosure is preferably a heat exchanger with a relatively low air resistance and a relatively large contact area for heat exchange.

[0047] A heat exchanger 3 for use in a system 1 according to the disclosure is preferably a once-through heat exchanger 3 comprising the first set of flow channels 18 and the second set of flow channels 19. In the Fig. 6, Fig. 6A and Fig. 6B schematically illustrates an embodiment of such a heat exchanger 3. A heat exchanger 3 for use in a system 1 according to the disclosure is preferably a heat exchanger of the type known as a fine-wire heat exchanger, for example, from NL9301439, which is incorporated by reference into this document at least for a better understanding of the structure and operation of a fine-wire heat exchanger.

[0048] In the heat exchanger 3, the first and second flow channels 18, 19 are separated from one another. The heat exchanger 3 preferably further comprises heat-conducting elements 24, such as preferably metal wire elements 24, which extend across the channels of the first set of flow channels 18 and the channels of the second set of flow channels 19, so that, as explained, during use, heat is transferred from the air flowing through the first set of flow channels 18 to the air flowing through the second set of flow channels 19 - or vice versa. The wire elements 14 extend, aligned substantially parallel to one another in their longitudinal axis L, at least partially across one of the first air inlet side 13 and the second air inlet side 16 and one of the first air outlet side 17 and the second air outlet side 14 of the heat exchanger 3, which is to be understood as meaning that air flows between the wire elements 24.The distance d, measured perpendicular to the longitudinal axis L, between adjacent wire elements 24 is, for example, between 2 times and 10 times, for example between 3 times and 5 times the largest cross-sectional dimension, such as the diameter D, of the wire elements 24. The wire element can, for example, but is not limited to, a cross-sectional dimension D of 0.1 mm, while a distance d between the wires perpendicular to the flow direction can be, for example, 0.5 mm and the distance d between wires in the flow direction can be, for example, 0.5 mm. These values ​​are given merely as examples.By selecting the number and dimensions of wire elements, as well as the spacing between the wire elements in one flow direction and in a direction perpendicular to the flow through the heat exchanger, the heat exchanger's characteristic curve, particularly the pressure-flow curve, can be adjusted so that the characteristic curve can be matched to the pressure-flow curves of the fans used. Condensation has been shown to be less problematic or even beneficial for the system if the spacing between adjacent wire elements is appropriate and not too small compared to the wire elements themselves. By selecting the spacing between the wires appropriately, if condensation occurs during use—for example, because the temperature of the corresponding airflow drops below the dew point—the condensate will not disappear due to the capillary action of the adjacent wires.By ensuring the distance between the wires is not too small, condensate will form in the form of droplets hanging from the wires, reducing the efficiency of the heat exchanger and thus the system. This can be detected by measuring the temperatures of the air streams at the first inlet, the first outlet, the second inlet, and the second outlet, and comparing a temperature difference between the first inlet and the first outlet, on the one hand, and the second inlet and the second outlet, on the other. If such a drop in efficiency is detected, at least one of the streams (into the building or out of the building) can be adjusted, preferably in such a way that the temperature of the air stream leaving the building is raised above the defrost point.

[0049] A fine-wire heat exchanger has the advantage of being simple to construct and having a relatively low air resistance, which can be easily adjusted during manufacture of the heat exchanger elements - for example, by selecting thinner or thicker wires, wires with a larger diameter D and / or by increasing or decreasing the distance d. For example, a heat exchanger for use in a system according to the disclosure has, measured at a volume flow between 10 and 60 m 3 / h, a flow resistance between 5 and 75 Pa.

[0050] In the Fig. 1, the system 1 is shown mounted in an opening 26 in a wall 25, preferably an exterior wall 25, so that air from the external space "OUTSIDE" can be directed to the space "INSIDE" within the building - and vice versa - through the system 1. Connected to or forming part of the system 1 is a controller 27 with which the system can be controlled - for example, by switching one or more of the fans 22, 23, 23A, 23B, if present, on and off, or by modulating the fan(s), for example based on inputs from sensors inside and / or outside the building, schematically shown in the form of squares 28 and 29. When operating a system 1 according to the disclosure, the fans 22, 23 can each be driven in a single direction.Their direction of rotation, and thus the direction of the air supply, does not need to be reversed periodically, as is required in prior art push-pull systems such as those provided by Lunos. This has the advantage, for example, of greatly increasing efficiency, since there is no time loss due to reversing the direction of rotation, while it is also unnecessary to store heat in a heat exchanger during a first period of time and to extract part of this stored heat during a subsequent, second period of time, which inevitably also leads to heat loss in the time interval between storage and extraction, while making it impossible to extract all of the stored heat. In a heat exchanger of a system according to the disclosure, the heat is preferably exchanged directly in the countercurrent flows.A further advantage of a system according to the disclosure compared to a prior art "push-pull" system, such as that known from Lunos, is that only one such system 1 is required for each "INTERIOR" room instead of two such systems. A system according to the disclosure can also be relatively quiet.

[0051] In the embodiment shown, the first fan 22 is rotated to draw air from the outside space "OUTSIDE" and force it through the heat exchanger 3, whereas the second fan 23 is rotated to draw air from the inside space "INSIDE" through the heat exchanger 3 and force it into the outside space "OUTSIDE". In general, with a system 1 according to the disclosure, the air in the "INSIDE" space within the building can be continuously refreshed, if desired, by removing heat from the air before it is expelled to the outside space "OUTSIDE" when the temperature of the air in the outside space "OUTSIDE" is lower than the temperature of the air in the inside space "INSIDE", thereby keeping the inside space "INSIDE" relatively warm.For example, in summer, when the air temperature in the outdoor space "OUTSIDE" is higher than in the indoor space "INSIDE", heat can be extracted from the air flowing into the indoor space "INSIDE" to be transferred to the air flow expelled from the indoor space "INSIDE" to the outdoor space "OUTSIDE", thereby keeping the indoor space "INSIDE" relatively cool.

[0052] The Fig. Figure 2 schematically shows an alternative embodiment of a system 1 according to the disclosure, which is mounted in an opening 26 in a wall 25. In this embodiment, the housing 1 comprises a tubular part 1A extending through the opening 26, wherein on the first side 12 an outer part 1B for attachment to an outer side of the wall 25 is connected to or formed integrally with the tubular part 1A. On the opposite second side 13, within the space "INSIDE" in the building, an inner housing part 1C, in which the heat exchanger 3 and the first fan 22 and the second fan 23 are accommodated, is connected to or formed integrally with the tubular part 1A. In this embodiment, a - preferably airtight - partition wall 27 extends from the heat exchanger 3 through the tubular part 1A and the outer part 1B and forms the first inlet duct 4 and the second outlet duct 7. In the Fig. 2, the system is shown in a position in which the first inlet channel 4 is located on an upward-facing side and the second outlet channel 7 is located on a downward-facing side of the system 1. However, by rotating the system, it can also be positioned differently.

[0053] In this embodiment, the heat exchanger is shown by way of example with a substantially diamond-shaped cross-section, wherein a short axis A 1 runs essentially parallel to the partition wall 27, for example horizontally, while a long axis A 2 for example, runs essentially parallel to the wall 25. In the Fig. 2, the heat exchanger 3 has the first inlet side 13 at the top on the right side and the second inlet side 16 at the top on the left side. The first outlet side 17 is provided at the bottom on the left side and the second outlet side 14 at the bottom on the right side. Here too, the first set of channels 18 extends between the first inlet side 13 and the first outlet side 17, and the second set of channels between the second inlet side 16 and the second outlet side 14. In this embodiment, the first fan 22 is opposite the axis A. 1 inclined in the first inlet duct 4. The second fan 23 is opposite the axis A 1 also inclined, but in the opposite direction. This allows for a compact design.

[0054] In the embodiment of the Fig. 2, the second inlet duct 5 extends upwards, for example substantially parallel to the wall 25, with the second air inlet 9 at the top. The first outlet duct 6 extends in the opposite direction, downwards, with the first air outlet 10 pointing downwards. During use, fresh air coming from the outside space "OUTSIDE" passes through the heat exchanger and is forced downwards by the first fan 22 through the first outlet 10 into the interior space "INSIDE", while used air is extracted from the interior space "INSIDE" by the second fan 23 through the second air inlet 9 and the heat exchanger 3.

[0055] In embodiments such as the one in the Fig. 2, the first air inlet 8 and the second air outlet 11 may be provided with louvres 30 or the like for guiding the air flow. Fig. 2, the slats 30 are angled such that used air is guided substantially downwards through the slats, thereby largely or completely preventing the used air from being drawn into the first inlet opening 8. The housing, in particular the inner part 1C, is preferably insulated and in particular has at least a sound-insulating and / or heat-insulating effect.

[0056] In a system 1 according to the disclosure, a heat exchanger preferably has a main plane A 1 with a longitudinal direction and a width direction perpendicular to the longitudinal direction, wherein on a first side of the heat exchanger 3 the first inlet side 13 is on a first side of the main plane A 1 and the second outlet side 17 on an opposite second side of the main plane A 1is provided and on the second side of the heat exchanger 3 the second inlet side 16 on the first side of the main level and the first outlet side 17 on the second side of the main level A 1 is provided, wherein the longitudinal direction Q of the main plane is substantially parallel to a longitudinal axis of a housing section in which the heat exchanger 3 is provided and which is in the Fig. 2, for example, extends parallel to an axis C of the opening 26. Preferably, each inlet opening 13, 16 and each outlet opening 17, 14 is provided in a plane which is aligned with the longitudinal direction A 1 the main plane forms an angle between 90 and 30 degrees, preferably between 90 and 45 degrees, for example between 90 and 60 degrees, wherein, as shown for example in the Fig. 2 to 8, the planes in side view preferably form substantially a rhombus or diamond shape or a hexagonal shape.

[0057] In the Fig. 6, a heat exchanger suitable for use in a system of the disclosure is shown in side section, while in the Fig. 6A and Fig. 6B shows a cross-section of the heat exchanger along the parallel planes VIA and VIB. Fig. 6 is the main level A 1 a heat exchanger 3 through the line A 1 indicated. This main plane runs perpendicular to the plane of the drawing, parallel to the planes VIA and VIB. Within a housing 31 of the heat exchanger 3, a series of vertically extending, partially open core elements 32 are provided, with at least one metal wire 24 wound around each core element or each combination of core elements, with adjacent wires 24 being spaced apart by distances d.

[0058] As can be seen from the Fig. 6 and Fig. 6B, is in a lower half of the heat exchanger, below level A 1, on the lower right side, a first row of wall elements 33 is provided, which are spaced apart from one another such that a row of first openings 34 is provided between the wall elements 33, which in this embodiment form the first inlet side 13 of the heat exchanger. On the opposite lower left side, a second row of wall elements 35 is provided, which are arranged such that they are directly opposite the first openings 34 between the first row of wall elements 33. Between the wall elements 35, in turn, a row of second openings 36 is provided, which are arranged directly opposite the wall elements of the first row. The second openings 36 form the second inlet side 16 of the heat exchanger in this embodiment.

[0059] The upper half of the heat exchanger is equal to the lower half, but inverted, so that, as shown in the Fig. 6 and the Fig. 6A, in the upper half of the heat exchanger 3, at the top left, a third row of wall elements 37 is provided directly above the second openings 36 between the second row of wall elements 35. Between the third row of wall elements 37, a third row of openings 38 is provided, which in this embodiment form the first outlet side 17 of the heat exchanger 3. On the opposite upper right side, a fourth row of wall elements 39 is provided directly above the first openings 34 between the first row of wall elements 33. Between the fourth wall elements 39, a fourth row of openings 40 is provided, which in this embodiment form the second outlet side 16 of the heat exchanger.

[0060] As can be seen from the Fig. 6, Fig. 6A and Fig. 6B, a first air flow 20 can flow into the heat exchanger through the first openings 34 and is forced through the openings between the wire elements 24 and upwards between the core elements 32 toward the third row of openings 38 and expelled, for example, into an interior space "INSIDE." At the same time, a second air flow 21 enters the heat exchanger 3 through the second openings 36 and is forced through the openings between the wire elements 24 and upwards between the core elements 32 toward the fourth row of openings 40 to be expelled, for example, into an exterior space "OUTSIDE."

[0061] As the second air stream 21 passes between the wire elements 24, it transfers heat to the wire elements 24, which conduct the heat along the wire elements 24. While the first air stream 21, if cooler, absorbs the heat from the wire elements 24 and is thus heated. As indicated, the general principle of such a wire heat exchanger is known from NL9301439.

[0062] The heat exchanger comprises at least one housing 41 and at least one core region or core element 32 and preferably a series of these, which form a Fig. 6 vertically extending main plane, wherein at least a part of the first and second set of channels 18, 19 is provided at least partially in the at least one core region. At least one metal wire 24 is wound around the at least one core region. As shown in the Fig. As shown in Figure 6, the core elements 32 are arranged one behind the other, with their main planes running parallel to each other. Separating elements are provided between adjacent wires 24, extending in a direction substantially perpendicular to a longitudinal direction of the wires 24. The separating elements can be, for example, additional core elements 32, rods, strips, or the like, which prevent the passage of air.

[0063] The Fig. 3 shows in cross-section an embodiment of a system 1 according to the disclosure, wherein the housing 2 is substantially tubular and preferably has a circular cross-section perpendicular to the longitudinal axis A-A. For mounting the system 1, a hole 26 can therefore easily be drilled into the wall 25 and also - if present - through the insulation 25A. In this embodiment, a partition wall 27 extends through the housing 2. A first part 27A of the partition wall divides a first section of the housing 2 at an outwardly directed end into the first inlet channel 4 and the second outlet channel 7, while a second part 27B of the partition wall 27 divides an opposite second section of the housing 2 into the second inlet channel 5 and the first outlet channel 6. In this embodiment, a heat exchanger 3, as shown, for example, in FIG. Fig. 6 is shown. The housing of the heat exchanger is closed to the inside of the tubular housing 2, so that all air flows 20, 21 flowing through the housing 2 flow through the heat exchanger 3. In this embodiment, the first fan 22 is arranged within the first inlet duct 4 and the second fan 23 is provided in the second outlet duct 7. As in the embodiment of the Fig. 2, the first and second fans 22, 23 are arranged at an angle to the partition wall 27, which means that the axis of rotation of the fan is inclined at an angle to the partition wall 27. This has the advantage that fans 22, 23 can be used that have a relatively large diameter W compared to the diameter Z of the housing 2.

[0064] The housing 2 comprises, on the first side 12, in the exterior space "OUTSIDE," the outer part 1B, which comprises the first air inlet 8 and the second air outlet 11. On the opposite second side 15, the housing 2 comprises, in the interior space "INSIDE," the inner part 1C, which comprises the second air inlet 9 and the first air outlet 10. Preferably, in a system 1 of the disclosure, at least one of the inner part 1C and the outer part 1B of the housing can be removed to gain access to the fans 22, 23 and / or the heat exchanger.

[0065] The Fig. 4 and Fig. 5 show a perspective view of an embodiment of a system 1 of the disclosure, which is similar to the one shown, for example, in Fig. 3 and which comprises the tubular housing section 1A and the end sections 1B, 1C. The housing 2 is shown transparent in order to show its contents. In this embodiment, the heat exchanger 3 has a circular flange 3A which seals against the inside of the housing section 1A and a circumferential horizontal flange 3B between the upper and lower parts of the heat exchanger. On the inward-facing side of the heat exchanger, a partition wall 27 bears against the flange 3B, while on the opposite side of the housing, the flange 3B bears against a flange 3D provided in or on the end section 1B. In this way, the inlet channels 4, 5 and the outlet channels 6, 7 are formed.In this embodiment, the first fan 22 is provided in the second inlet duct 5, and the second fan 23 is provided in the first outlet duct 6, thus on the side of the system facing the interior space. The fans 22, 23 are therefore easily accessible by removing the end section 1C. The end sections 1B, 1C, in turn, comprise the air inlets and the air outlets.

[0066] In this embodiment, the first fan 22 and the second fan 23 are shown as centrifugal fans arranged directly on the partition wall 27 and whose rotational axis is oriented perpendicular to the partition wall 27. Between the first fan 22 and the heat exchanger 3, a first wall part 42 is provided, which comprises an outlet side 43 of the fan 22. A pivotable flap 44 can be provided, which can close the outlet side 43 and opens when air is forced out by the first fan. Fig. 4 and Fig. 5, the flap 44 is shown in the open position. Thus, the flap 44 can prevent air from flowing in the opposite direction when the fan 22 is turned off. Similarly, a second wall 45 is provided between the second fan 23 and the inner end portion 1C, which wall encloses the outlet opening of the second fan 23.

[0067] The Fig. Figure 7 shows a partially exploded view of another embodiment of a system 1 of the disclosure, wherein the Fig. 1 and 3 to 5 similar tubular housing part 1A is removed. Also in this embodiment, the heat exchanger 3, as in the Fig. 4 and Fig. 5, to a flange 3D of the end section 1C, which end section comprises the corresponding inlet 9 and the corresponding outlet 10. At the opposite end of the system 1, the end section 1B is provided with the other inlet 8 and the other outlet 11. In this embodiment, a partition wall 27 is provided between the flange 3D of the heat exchanger and the end section 1B, the partition wall 27 having a first part 27A which is connected to the end section 1C, the first part 27A being in the Fig. 7, extends at a downward angle. A second part 27B is connected to the first part 27A and extends largely at an upward angle, for example substantially perpendicular to the first part 27A. A third part 27C is connected to the second part 27B opposite the first part 27A and extends substantially parallel to the first part 27A. As previously explained, during use the partition wall 27 seals against an inner side of the housing part 1A. The first fan 22, which is shown as an axial fan, is mounted on the first wall part 27A below and at a distance from the second wall part 27B. The second fan 23 is mounted above and at a distance from the second wall part 27B on the opposite side thereof on the third wall part 27C.

[0068] In this embodiment, the heat exchanger is shown at one end of the system facing an interior space "INSIDE", allowing easy disassembly of the combination of the end section 1C, the heat exchanger 3, and the fans 22, 23. For this purpose, the partition wall 27 is connected to the end section 1C, for example by a connecting piece 46. In the Fig. In Figure 7, the first airflow 20 and the second airflow 21 are schematically represented by striped arrows. The first airflow 20, drawn in by the fan 23, flows from the first inlet 8 into the housing 2, remains above the second partition wall section 27B, then passes through the heat exchanger 3 and exits the system 1 through the outlet 10 into the interior space "INSIDE." The second airflow 21 flows through the second inlet 9, flows downward through the heat exchanger 3 due to the pressure of the fan 22, remains below the second partition wall section 27B, and flows out the outlet 11 to the outside.

[0069] The Fig. 8, Fig. 8A and Fig. 8B show a further alternative embodiment of a system 1, in which the housing 1 is substantially box-shaped and comprises, for example, a rectangular bottom wall 50 and a peripheral wall 51 extending therefrom. A transverse wall 52 extending over the bottom wall divides the interior of the housing into two parts 53 and 54. A first tube 55 is connected to the first part 53, and a second tube 56 is connected to the second part 54. The first fan 22 is provided in or on the bottom wall 50 at the end of the first tube 55. The second fan 23 is provided in or on the bottom wall 50 at the end of the second tube 56. The fans here are axial fans.

[0070] In the Fig. 8A, the heat exchanger has been removed so that the bottom wall and the fans 22, 23 are visible. In the Fig. 8 and Fig. 8B shows the heat exchanger 3, which in this embodiment, similar to the Fig. 2, a heat exchanger 3 with a substantially diamond-shaped cross-section. The heat exchanger in turn has a housing 41 with a flange 3B, which in this embodiment is connected to the transverse wall 52 and preferably seals against it. During use, a cover 57 is mounted over the heat exchanger 3, sealing against the peripheral wall 51. The cover 57 comprises the first air outlet 10 and the second air inlet 9.

[0071] For the installation of this embodiment, two openings 26 are formed in a wall 25 at a suitable distance, one above the other or side by side. The first pipe 55 is inserted into a first of the openings 26, the second pipe 56 into the other opening 26. Air from outside is sucked into the first pipe 55 by the first fan 22 and flows into the heat exchanger 3, to be expelled from the system through the first air outlet 10 within the "INSIDE" space in the building. At the same time, air from the "INSIDE" space is sucked into the heat exchanger 3 by the second fan 23, to be expelled from the "INSIDE" space through the second pipe 56 out of building B.

[0072] As explained, with a system according to the disclosure, indoor air or stale air in an interior space "IN" within a building can be replaced by outdoor air or fresh air from an outdoor space "OUT", using at least two fans each driven in a single direction without the need to reverse either direction of rotation, whereby heat can be exchanged between opposing air flows throughout the entire time the fans are operating, which is known as the countercurrent or counterflow principle. The operation of the fans 22, 23 can, for example, be controlled by a controller - for example, based on a level of CO detected within the interior space "IN". 2 -content or particle content. For example, the fans can be switched on and off or modulated.

[0073] In the Fig. 9 is - here only as an example in a general, the Fig. 1 - a system 1 is schematically shown in which a first sensor 47 is provided in or on the first air inlet 8. A second sensor 48 is provided in or on the first air outlet 10. A third sensor 49 is provided in or on the second air inlet 9, while a fourth sensor 50 is provided in or on the second air outlet 11. It is understood that these sensors could also be provided in the corresponding ducts, closer to the fans, or at least connected to these inlets, outlets, and / or ducts. The first to fourth sensors 47 to 50 are connected to the controller 27 by wires or, for example, wirelessly. It should be understood that the sensors 47 to 50 can be provided in a similar manner in the various other embodiments disclosed herein.

[0074] In embodiments, the sensors 47 to 50 may be or at least comprise temperature sensors - such as digital temperature sensors - to measure the following: - the temperature T 8 the air flowing into the first air inlet 8; - the temperature T 10 the air flowing out of the first air outlet 10; - the temperature T 9 the air flowing into the second air inlet 9; and - the temperature T 11 the air flowing out of the second air outlet 11.

[0075] In the control 27, on the one hand, a temperature difference TD 1 between T 8 and T 10 and on the other hand a temperature difference TD 2 between T 9 and T 11 In the control system 27, the temperature differences TD 1 and TD 2compared with each other. If these are essentially the same, it can be concluded that the air flows entering the interior space "INSIDE" and leaving the interior space "INSIDE" to the exterior space "OUTSIDE" are optimally coordinated and, in particular, are equal in terms of volume per hour. However, if it is determined that the temperature differences TD 1 and TD 2 are not equal, especially if the difference is above a threshold value—a preset value in the controller 27—the flows are not properly coordinated. Then, the flow rate in at least one of the channels of the heat exchanger is controlled by increasing or decreasing this flow rate relative to the flow rate in the other channel. For this purpose, for example, the speed of at least one of the fans 22, 23 can be changed, for example, increased, relative to the speed of the other of the fans 23, 22.

[0076] For example, if it is determined that the first temperature difference TD 1 is smaller than the second temperature difference TD 2, and the temperature in the outdoor space "OUTSIDE" is lower than the temperature in the indoor space "INSIDE", it can be deduced that the heat transferred by the air flow flowing from the indoor space "INSIDE" is greater than the heat that the air flow flowing into the indoor space "INSIDE" can absorb from the heat exchanger 3, thereby heating the heat exchanger, resulting in a reduced ability of the heat exchanger 3 to absorb the heat expelled from the indoor space "INSIDE" and thus in a reduction in the efficiency of the heat exchanger. By reducing the speed of the first fan 22 in such a case, the heat exchange between the air flow flowing into the indoor space "INSIDE" can be adjusted so that the air flowing into the indoor space "INSIDE" can recover more heat from the heat exchanger.It is understood that in a similar way the speed of the first and / or the second fan depends on the temperature differences TD. 1 and TD 2 and can be adjusted upwards or downwards, for example, depending on the air temperatures in the interior space "INSIDE" and in the exterior space "OUTSIDE". A change in the flow can, for example, be caused by an increasing or decreasing wind pressure on the first air inlet 8 and / or the second air outlet 11, or may be required due to an increase or decrease in the temperature in the interior space "INSIDE" relative to the temperature in the exterior space "OUTSIDE".

[0077] In embodiments, at least one, preferably at least two of the sensors 47 to 50 and / or 28 or 29 can be or include humidity sensors for measuring the relative or absolute humidity of the air flowing into and / or out of the heat exchanger. By monitoring the humidity of at least one flow, and preferably both the flow into the interior space "INSIDE" and the flow out of the interior space "INSIDE", the speed of the fan can be controlled based on a discrepancy between the desired humidity in the interior space "INSIDE" and the humidity measured or calculated in this interior space "INSIDE". In this way, an optimal setting of the speeds can be controlled at any time.

[0078] In embodiments, at least one of the sensors 47 to 50 and / or 28 or 29 may be a CO 2 - and / or CO sensor - especially for measuring a CO 2- and / or CO content of air flowing out of the interior "INSIDE" as an indication of the CO 2 and / or CO levels within the "INDOOR" compartment. Based on such an indication, the airflow out of the "INDOOR" compartment can be increased or decreased. Preferably, at the same time, the airflow into the "INDOOR" compartment is adjusted accordingly so that the airflows are kept within the preset, permissible difference.

[0079] In embodiments, the controller is or can be set to turn off one of the fans 22, 23, preferably the second fan 23, or to reduce its speed, so that while air continues to be drawn into the interior space "INSIDE," it is at least substantially expelled from the interior space "INSIDE" not through the heat exchanger, but rather, for example, through gaps or slots under or around doors and / or windows or in some other way. This can be particularly advantageous during the night to reduce noise and energy consumption.

[0080] Fans used in systems of the disclosure are preferably speed-controllable or modulating fans so that the pressure they generate can be adjusted or controlled by changing the speed.

[0081] The Fig. Figure 10 schematically shows a comparison diagram between a system according to the prior art, which comprises an axial fan and a ceramic heat exchanger, and a system according to this disclosure, which in embodiments comprises a centrifugal fan and a wire heat exchanger, such as that described in Fig. 6 is shown. In the Fig. 10 is on the horizontal axis the volume flow of air in m 3 / h and the vertical axis shows the pressure in Pa. The hatched area I in the diagram shows the flow resistance of a wire heat exchanger, with the solid line L 1 indicates a preferred combination of pressure and flow rate for a wire heat exchanger to be used. The hatched area II in the Fig. Figure 10 shows the flow resistance of a ceramic heat exchanger as used in systems according to the state of the art, such as the Lunos system, where the solid line L2 a preferred combination of pressure and flow rate for a ceramic heat exchanger as used in the prior art. As explained, in the prior art systems, an axial fan must be used to reverse the direction of rotation and thus the flow.

[0082] In the Fig. Figure 10 shows pressure-flow curves in dotted lines for various axial and centrifugal fans. In the lower left corner, a first pressure-flow curve PF is shown. 1 for a first axial fan and a second pressure-volume flow curve PF 2for a second axial fan that has a larger diameter and / or rotates at a higher speed than the first axial fan. With a fan, the pressure obtained decreases with increasing flow rate. With axial fans, the achievable pressure is relatively low even at low flow rate, while the pressure decreases relatively quickly with increasing flow rate. For a system according to the state of the art, in which an axial fan and a ceramic heat exchanger are used, Fig. 10 a practical working range is indicated by a vertical line W to the left of this line. For a system according to the state of the art, an optimum is therefore found in the combination of a pressure P m with a volume flow F m This volume flow is required to achieve a minimum refreshment rate of, for example, 60m 3 / h. The pressure P mis significantly lower than the maximum achievable pressure to achieve the required minimum flow rate. As can be seen from the Fig. As can be seen in Figure 10, the pressure can be increased for the same flow rate, or vice versa, by increasing the size and / or speed of the fan, but this has the disadvantage that the noise level also increases significantly. Furthermore, the increase in the pressure-to-flow ratio is limited. It has been shown that in the known prior art systems, with increasing wind load on the system, for example when there is wind pressure on the inlet or outlet of the system, the axial fan becomes less effective - particularly in forcing air out of the building - thereby significantly reducing the system efficiency - in particular the refreshment rate and the heat exchange efficiency. This is further reduced by the necessary periodic reversal of the direction of rotation of the fan, which requires a period during which no airflow is achieved, since the fan must be stopped and started again.

[0083] In the Fig. 10 also shows the pressure-volume flow curves PF 3 , PF 4 and PF 5 for three centrifugal blowers or fans used in a system according to the present disclosure with increasing size and / or speed. In the Fig. 10 is the size, especially an outer diameter of the axial fan with the curve PF 1 essentially equal to the size of the centrifugal fan with the curve PF 3 , while the size, especially an outer diameter of the axial fan with the curve PF 2 essentially equal to the size of the centrifugal fan with the curve PF 5 while the size of the centrifugal fan is determined by the curve FP 4 between the size of the centrifugal blowers with the curves FP 3 and FP 5 As can be seen from the Fig. As can be seen from Figure 10, the pressure P achievable with centrifugal fans is significantly higher than that of axial fans, while the volume flow F is relatively constant and relatively high over a large pressure range, which is evident from the steep tangent T C on the pressure-volume flow curves PF, especially in comparison to the tangent T A the curve of an axial fan.

[0084] As in the Fig. 10, for the combination of a wire heat exchanger, as explained, with a centrifugal fan, as explained, in the working area I of the wire heat exchanger, an optimal combination C opt from a pressure P c and a volume flow F c be selected, whereby both the pressure P c as well as the volume flow F care relatively high compared to an axial fan and a ceramic heat exchanger. For example, a high exchange rate can be achieved while overcoming relatively high wind pressures.

[0085] In a system according to the disclosure, a fan-heat exchanger combination is preferably operated at or in an optimum C opt which is defined by the point of contact between a pressure-volume flow curve P F a specific fan and a hyperbola H c which indicates the air performance of the fan, which is defined as pressure times volume flow (P*F = W), where the pressure P is given by N / m 2 and the volume flow through F=m 3 / s and W is the power in Nm / s. In the Fig. 10 this point of contact is C opt for the second pressure-volume flow curve PF 2shown. It is clear that such a hyperbola and such a tangent point can be defined for each fan. For a given desired flow rate F or a given desired refreshment rate, an optimal centrifugal fan based on a heat exchanger used, or an optimal heat exchanger based on a fan to be used, or a combination of these, can be selected in region I, which is suitable for providing sufficient pressure during use to overcome the wind pressure on the system, or vice versa.

[0086] In the present disclosure, a fan used in the system may be an axial fan with guide vanes, which allows for higher pressures since the direction of rotation does not need to be reversed during use. Centrifugal fans are preferably used. In a system according to the present disclosure, the speed of the fans may be increased or decreased during use depending on, for example, one or more of: a desired noise level, a desired refreshment rate for the interior, the wind pressure on the system, and the like, as well as, for example, based on one or more of: a measured CO2 and / or CO level and / or fine particles in the air, odor and humidity, or, for example, based on a dew point and / or by the controller 27, as explained.

[0087] By using fans with a relatively high maximum pressure and a suitable flow rate at different pressures, i.e. with a steep tangent, as explained, the fans can be driven at relatively low speeds, thus avoiding undesirable turbulence at the blade tips of the fan and thus reducing noise.

[0088] By way of example and without limiting the scope of the disclosure, a centrifugal fan with a wire heat exchanger may be used, wherein the fan may have a diameter or cross-section of 120 mm, wherein the optimum point or contact point C opt at a pressure Pc of about 130 Pa at a volume flow of about 70 m 3 / h is selected or can be selected. For example, if a similar fan with a diameter of 133 mm is used and driven at a similar speed, a pressure of about 180 Pa and a volume flow of about 90 m 3 / h can be achieved. These systems are capable of overcoming wind pressures on the system of, for example, 20 Pa or more, without the risk of unwanted outside air being blown through the system into the building. Furthermore, by using a control system as explained, the airflow into the room and the airflow out of the room can be balanced - for example, by changing the speed of one or both fans and / or, for example, by throttling the airflow on one side of the heat exchanger - so as to achieve optimum heat transfer and thus optimum efficiency.

[0089] The invention is by no means limited to the embodiments shown and described above merely by way of example. Many variations are possible within the scope of the disclosure. For example, the heat exchanger may be a different type of flow-through heat exchanger. The housing may be designed differently—for example, with air inlets and / or air outlets in different positions or in different orientations. A system may have a plurality of first and / or second inlets and / or outlets. As explained, a system of the disclosure may be provided in a door or window forming part of an exterior wall. The description describes a system that draws air from and expels air into an exterior space "OUTSIDE." It is obvious that such an exterior space "OUTSIDE" could also be another space in a building, for example, an atrium or other space with relatively fresh air.

[0090] These and similar alternatives should be considered as also disclosed and within the scope of the disclosure. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] US 9,845,959 [0004, 0007] WO 99 / 13284

[0007] DE 4440436

[0008] SE 507252

[0008] NL 9301439 [0047, 0061]

Claims

[1] Ventilation system for installation in a building wall, comprising a housing with a heat exchanger and at least a first inlet duct and a second inlet duct, a first outlet duct and a second outlet duct, a first air inlet, a second air inlet, a first air outlet and a second air outlet, wherein: on a first side of the heat exchanger: - the first inlet duct connects the first air inlet to a first inlet side of the heat exchanger and the second outlet duct connects the second air outlet to a second outlet side of the heat exchanger, and on a second side of the heat exchanger: - the second inlet channel connects the second air inlet to a second inlet side of the heat exchanger and the first outlet channel connects a first outlet side of the heat exchanger to the first air outlet; wherein, within the heat exchanger, the first inlet side is connected to the first outlet side by a first set of flow channels and the second inlet side is connected to the second outlet side by a second set of flow channels, so that during use, heat can be exchanged between air in the first set of flow channels and air in the second set of flow channels, wherein at least one first fan is provided in at least one of the first inlet channel and the first outlet channel, and at least one second fan is provided in at least one of the second inlet channel and the second outlet channel. [2] A ventilation system according to claim 1, wherein the housing comprises a tubular portion, at least a portion of the first inlet duct and a portion of the second outlet duct extending in a side-by-side arrangement through the tubular portion, the tubular portion preferably having a substantially circular cross-section. [3] The ventilation system of claim 1 or 2, wherein the heat exchanger is a once-through heat exchanger comprising the first set of flow channels and the second set of flow channels, the first and second flow channels being separated from each other, the heat exchanger further comprising heat-conducting metal wire elements extending across channels of the first set of flow channels and channels of the second set of flow channels such that, during use, heat is transferred from the air flowing through the first set of flow channels to the air flowing through the second set of flow channels, or vice versa. [4] Ventilation system according to claim 3, wherein the wire elements extend with their longitudinal axis substantially parallel to one another at least partially over any one of the first and second air inlet sides and the first and second air outlet sides of the heat exchanger, wherein the distance perpendicular to the longitudinal axis between adjacent wire elements is between 2 times and 10 times, preferably between 3 times and 5 times the largest cross-sectional dimension of the wire elements. [5] Ventilation system according to one of the preceding claims, wherein a control is provided which is designed to operate the first fan and the second fan separately, preferably independently of each other, wherein the first and the second fan are preferably modulating fans. [6] Ventilation system according to one of the preceding claims, wherein sensors are provided which are connected to a controller of the system which is designed to operate the fans in dependence on at least the signals received from the sensors to balance the air flow through the ducts. [7] Ventilation system according to claim 6, wherein the sensors are or at least comprise temperature sensors with which a temperature increase or decrease can be measured across ducts in which the sensors are provided. [8] Ventilation system according to one of the preceding claims, wherein the heat exchanger, measured at a volume flow between 10 and 60 m 3 / h, has a flow resistance between 5 and 75 Pa. [9] Ventilation system according to one of the preceding claims, wherein the heat exchanger has a main plane with a longitudinal direction and a width direction, wherein: - on a first side of the heat exchanger, the first inlet side is provided on a first side of the main plane and the second outlet side is provided on an opposite second side of the main plane, and - on an opposite second side of the heat exchanger, the second inlet side is provided on the first side of the main plane and the first outlet side is provided on the second side of the main plane, wherein the longitudinal direction of the main plane runs substantially parallel to a longitudinal axis of a housing section in which the heat exchanger is provided. [10] Ventilation system according to claim 9, wherein each of the first and second inlet sides comprises at least one inlet opening and each of the first and second outlet sides comprises at least one outlet opening, wherein each inlet opening and each outlet opening is provided in a plane which encloses an angle between 90 and 30 degrees, preferably between 90 and 45 degrees, for example between 90 and 60 degrees, with the longitudinal direction of the main plane, wherein the planes in side view preferably form a substantially rhombus or diamond shape. [11] A ventilation system according to claim 9 or 10, wherein the heat exchanger comprises at least one core region having a main plane, wherein at least a part of the first and second set of channels is provided at least partially in the at least one core region, wherein at least one metal wire extending through and / or over the flow channels is wound around the at least one core region, the main plane of the or each core being substantially perpendicular to a longitudinal direction of the heat exchanger. [12] Ventilation system according to claim 11, wherein a row of the core regions is arranged one behind the other in the longitudinal direction, with their main planes running parallel to each other. [13] Ventilation system according to claim 11 or 12, wherein separating elements extending between adjacent wires are provided, which extend in a direction substantially perpendicular to a longitudinal direction of the wires. [14] Ventilation system according to one of claims 1 to 13, wherein the fans are axial fans. [15] Ventilation system according to one of claims 1 to 13, wherein the fans are centrifugal fans. [16] Ventilation system according to one of the preceding claims, wherein the housing is substantially tubular, preferably having a substantially circular cross-section and a longitudinal direction, wherein the heat exchanger is provided in the housing in a sealing manner against an inner surface of the housing and divides an inner volume of the housing into at least an outer end portion and an inner end portion, wherein at the outer end portion a first partition wall extends from the heat exchanger in the longitudinal direction and divides the outer end portion into the first inlet duct and the second outlet duct, and wherein the inner end portion comprises the second inlet duct and the first outlet duct. [17] Ventilation system according to claim 16, wherein the first fan is provided in the first inlet duct and the second fan is provided in the second outlet duct. [18] Ventilation system according to claim 17, wherein the first fan is a centrifugal fan with a rotation axis substantially perpendicular to the longitudinal direction of the housing and the second fan is a centrifugal fan with a rotation axis substantially perpendicular to the longitudinal direction of the housing, wherein: - a first partition wall is provided in the first inlet channel, which divides the first inlet channel into a first proximal end between the first air inlet and the first partition wall and a first distal end between the first partition wall and the heat exchanger, wherein the first fan is provided in the first proximal end and an opening is provided in the first partition wall which connects the first fan to the first distal end; and - a second partition wall is provided in the second outlet channel, which divides the second outlet channel into a second proximal end between the first air outlet and the second partition wall and a second distal end between the second partition wall and the heat exchanger, wherein the second fan is provided in the second distal end and an opening is provided in the second partition wall which connects the second fan to the second proximal end. [19] Ventilation system according to claim 17, wherein the first fan is an axial fan with a rotation axis substantially perpendicular to the longitudinal direction of the housing and the second fan is an axial fan with a rotation axis substantially perpendicular to the longitudinal direction of the housing, wherein: - a first partition wall is provided in the first inlet channel, which divides the first inlet channel into a first proximal end between the first air inlet and the first partition wall and a first distal end between the first partition wall and the heat exchanger, wherein the first fan is provided in the first proximal end and an opening is provided in the first partition wall which connects the first fan to the first distal end; and - a second partition wall is provided in the second outlet channel, which divides the second outlet channel into a second proximal end between the first air outlet and the second partition wall and a second distal end between the second partition wall and the heat exchanger, wherein the second fan is provided in the second distal end and an opening is provided in the second partition wall which connects the second fan to the second proximal end.

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