An alternating bidirectional fan and a system for ventilating the air in a room

Abstract

An alternating bidirectional fan (1) comprising an impeller (10), and a motor (3) for rotating the impeller (10), a first side (11) and an opposite second side (12), and the alternating bidirectional fan (1) being characterized by comprising an alternating bidirectional air guide (4, 4', 4'') arranged radially outside the impeller (10), and an in-flow guide (5) arranged on the inflow side (7) of the alternating bidirectional fan (1), the alternating bidirectional air guide (4, 4', 4'') and the in-flow guide (5) being rotationally connected, wherein the alternating bidirectional fan (1) is configured to alternate an air flow through the alternating bidirectional fan (1) by shifting the alternating bidirectional air guide (4, 4', 4'') and the in-flow guide (5) between a first position and a second position. The disclosure further relates to a system for ventilating the air in a room.

Description

[0001] An alternating bidirectional fan and a system for ventilating the air in a room

[0002] Technical field

[0003] The present disclosure relates to an alternating bidirectional fan with optional air filtering and / or heat exchange capabilities and a system for ventilating the air in a room, and optionally with reduced heat loss. More specifically, the disclosure relates to an alternating bidirectional fan and a system for ventilating the air in a room as defined in the introductory parts of the independent claims 1 and 8.

[0004] Background art

[0005] Present disclosure provides an air filtering device or a heat exchange air filtering device having unprecedented characteristics compared to any prior art. A problem with the solutions of the prior art is they have low filtration efficiency, they are bulky and noisy. Compact systems requires more energy to achieve acceptable flow and thermal efficiency.

[0006] In US2023 / 0204256 it is shown an air conditioner including: a housing including a cylinder portion, an inlet and an outlet formed in a lower portion of the cylinder portion and being in a shape of an arc; a heat exchanger positioned inside the cylinder portion and being in a shape of an arc; and a plurality of blades configured to selectively open or block the outlet.

[0007] Ventilation systems with both heat recovery and high filtration efficiency require a lot of space and are power demanding, and as a result, when run they run with high noise levels. High noise, and high power consumption are incompatible characteristics for a ventilation system and is in general unwanted.

[0008] A further problem related to air ventilation appears in rooms primarily needed to be ventilated, such as meeting rooms, class rooms, private housing rooms, larger rooms and confined spaces. Traditionally such rooms have been ventilated using one fan blowing into the room, and one blowing out of the room. Alternatively pulsed ventilation devices with complex bidirectional features including turning the fan direction has been offered. These solutions are space demanding, expensive and has a tendency to have low efficiency when using much of the time turning the air flow direction.

[0009] Additionally there is typically a challenge with noise when the filters clog. There is thus a need for compact systems with better ventilation efficiency or higher filtering and heat exchange efficiency emitting low noise and having a low power consumption.

[0010] It is an object of the present disclosure to mitigate, alleviate or eliminate one or more of the above-identified deficiencies and disadvantages in the prior art and solve at least the above mentioned problems.

[0011] Although, the present disclosure mainly solves challenges and problems related to air ventilation including heat exchange features, it has been recognized that the core of the present disclosure also solves a more basic air ventilation task when provided in a stripped version without heat exchange capabilities, and even without air filtering capabilities.

[0012] Thus, according to a first aspect there is provided an alternating bidirectional fan comprising an impeller, and a motor for rotating the impeller, a first side and an opposite second side, an alternating bidirectional air guide arranged radially outside the impeller, and an in-flow guide arranged on the inflow side of the alternating bidirectional fan, the alternating bidirectional air guide and the in-flow guide being rotationally connected.

[0013] There is an advantage by providing air guides changing the air flow independent of the position of the motor and impeller which will operate continuously in same position independent of air flow direction.

[0014] According to a further aspect the alternating bidirectional fan further comprising a one- way-flow air filter being rotationally connected to the impeller.

[0015] According to a further aspect of the alternating bidirectional fan, the one-way-flow air filter is a one-way-flow pulse heat exchange air filter. According to a further aspect there is provided an alternating bidirectional fan comprising: a one-way-flow air filter, an impeller, and a motor for rotating the the impeller and the one- way-flow air filter, a first side and an opposite second side, and the one-way-flow air filter further comprising: an alternating bidirectional air guide arranged radially outside the one- way-flow air filter, and an in-flow guide arranged on the inflow side of the one-way-flow air filter, the alternating bidirectional air guide and the in-flow guide being rotationally connected.

[0016] According to a further aspect there is provided an alternating bidirectional fancomprising: a one-way-flow pulse heat exchanging air filter, an impeller, and a motor for rotating the the impeller and the one-way-flow pulse heat exchanging air filter, a warm side and an opposite cold side, and the one-way-flow pulse heat exchanging air filter operating as a first pulsed heat exchanger, further comprising: an alternating bidirectional air guide arranged radially outside the one-way-flow pulse heat exchanging air filter, and an in-flow guide arranged on the inflow side of the one-way-flow pulse heat exchanging air filter, the alternating bidirectional air guide and the in-flow guide being rotationally connected.

[0017] The one-way-flow pulse heat exchanging air filter rotates continuously in one direction, and alters between either only pumping air from warm to cold side, or the opposite direction from cold to warm side.

[0018] According to some embodiments, the one-way-flow pulse heat exchanging air filter further comprises one or more of: the one-way-flow air filter is a rotating pleated filter, and the impeller is a rotationally connected morphed impeller.

[0019] There is an advantage having a pleated air filter, which enables the device according to present disclosure to provide optimal air filtering and heat storing characteristics.

[0020] According to some embodiments, the alternating bidirectional air guide being constructed with a first part of a snail house comprising a radially expanding air duct, and a second part of the snail house comprising one of: - an opening, or

[0021] - a radially decreasing air duct comprising one or more of:

[0022] - a second pulsed heat exchanger, and

[0023] - a mesh for eddie / turbulence reduction.

[0024] There is a further advantage with the device according to present disclosure in that the comprised parts of the second part of the snail house are optional, and the air exit section may advantageously provide a further pulsed heat exchanger for increased heat exchange efficiency and / or a mesh. The snail house further comprise a encircling top and bottom.

[0025] According to some embodiments: the heat exchange air filtering device further comprises a static air flow guide being constructed to:

[0026] - separate the air in-flow from the following out-flow at the warm side, of the one-way- flow pulse heat exchanging air filter.

[0027] The warm side of the heat exchanging device may separate inflow area from outflow area to reduce recirculation. It is possible to arrange a corresponding static air flow guide on the cold side.

[0028] According to some embodiments, the in-flow guide is arranged on the opposite side of the air in-flow to the position of the first part of the snail house of the alternating bidirectional air guide for guiding air into the one-way-flow pulse heat exchanging air filter, such that when the alternating bidirectional air guide is in a first locked position the air flows from the warm side of the heat exchange air filtering device into the one-way-flow pulse heat exchanging air filter and out of the one-way-flow pulse heat exchanging air filter to the cold side of the heat exchange air filtering device, and when the alternating bidirectional air guide is in a second locked position the air flows from the cold side of the heat exchange air filtering device into the one-way-flow pulse heat exchanging air filter and out of the one-way-flow pulse heat exchanging air filter to the warm side of the heat exchange air filtering device.

[0029] The device according to present disclosure provides air flow only in one direction at a time. According to some embodiments, the heat exchange air filtering device comprises a rotation control device for controlling an alternating duty cycle of the heat exchange air filtering device, and a controller, controlling the rotation control device, wherein the rotation control device is arranged to lock-step the alternating bidirectional air guide and the rotationally connected in-flow guide, and the lock-step motion is provided by one of:

[0030] - the momentum of the spinning air flow exiting the one-way-flow pulse heat exchanging air filter, or

[0031] - an actuator.

[0032] The device according to present disclosure need little additional parts for controlling the angular positions of the in-flow guide and the rotationally connected snail house.

[0033] According to some embodiments, the heat exchange air filtering device comprises: a static push-pull heat exchanger arranged at the cold and / or the warm side of the one-way- flow pulse heat exchanging air filter.

[0034] According to a second aspect there is provided a system for ventilation of the air in a room with reduced heat loss, the system comprising: two or more alternating bidirectional fans as described in the first aspect, and any of the two or more alternating bidirectional fans operating in an antiphase pattern with any other of the two or more alternating bidirectional fans.

[0035] In an advantageous embodiment the heat exchange filtering devices operate in pairs, and their running cycles are configured to run in antiphase, such that if one airflow is pumped in warm-to-cold direction, the other heat exchange filtering device in the pair is pumping an airflow in cold-to-warm direction.

[0036] According to some embodiments, the alternating bidirectional fan further comprising a one-way-flow air filter being rotationally connected to the impeller. According to some embodiments, the one-way-flow air filter is a heat exchange air filtering device.

[0037] According to some embodiments, the anti-phase pattern are pre-configurable or dynamically configurable.

[0038] Effects and features of the second aspect are to a large extent analogous to those described above in connection with the first aspect. Embodiments mentioned in relation to the first aspect are largely compatible with the second aspect.

[0039] The present disclosure will become apparent from the detailed description given below. The detailed description and specific examples disclose preferred embodiments of the disclosure by way of illustration only. Those skilled in the art understand from guidance in the detailed description that changes and modifications may be made within the scope of the disclosure.

[0040] Hence, it is to be understood that the herein disclosed disclosure is not limited to the particular component parts of the device described or steps of the methods described since such device and method may vary. It is also to be understood that the terminology used herein is for purpose of describing particular embodiments only, and is not intended to be limiting. It should be noted that, as used in the specification and the appended claim, the articles "a", "an", "the", and "said" are intended to mean that there are one or more of the elements unless the context explicitly dictates otherwise. Thus, for example, reference to "a unit" or "the unit" may include several devices, and the like. Furthermore, the words "comprising", "including", "containing" and similar wordings does not exclude other elements or steps.

[0041] Terminology :

[0042] The term "warm side" is used on the right side of the figures. It will typically be the room (in cold climates to be ventilated (in cold climates). The term "cold side" is used on the left side of the figures, typically outdoor when in cold climates, and then represent the fresh air side (when air outside for example has lower CO2, VOC etc.). It should be understood that the techniques described in present disclosure is the same also when warm / cold name configuration is changed (warm climate).

[0043] The term "warm side" and "cold side" shall further be interpreted as also representing the first side and the second side correspondingly, and the use of first / second and warm / cold respectively shall be understood to describe the same elements / sides. First and second side is also better describing the features when the device of present disclosure does not comprise heat exchange elements.

[0044] When the term "motor" is used it should be understood to also comprise any necessary power sources, cables, controllers, brackets, axels and gears necessary for the motor to function as the driving force of the components of the present disclosure.

[0045] The term "lock-step" is used to describe that the stepwise position of the alternating bidirectional air guide and the rotationally connected in-flow guide is rotated in steps defined by a duty cycle, and shifting between two positions in the embodiments shown in present disclosure, separated by 180°. The alternating bidirectional air guide and the rotationally connected in-flow guide is locked in a first position for a period before it is stepped / rotated to the second position for a further period, before moving to the first position again, and then repeating.

[0046] The term "alternating bidirectional fan" is used to describe the device of the present invention when discussing core air flow direction features, whilst the term "heat exchange filtering device" is used to describe the device of the present invention when discussing embodiments related to heat exchange features. The two terms may be used alternately. Brief descriptions of the drawings

[0047] The above objects, as well as additional objects, features and advantages of the present disclosure, will be more fully appreciated by reference to the following illustrative and non-limiting detailed description of example embodiments of the present disclosure, when taken in conjunction with the accompanying drawings. Figure 1A shows a perspective view of the heat exchange filtering device when providing a warm-to-cold air flow direction, and showing a longitudinal cross section cut on one side, according to an embodiment of the present disclosure.

[0048] Figure IB shows vital parts of the heat exchange filtering device when providing a cold- to warm air flow direction.

[0049] Figure 2 shows a vertical cross section in the longitudinal direction of the heat exchange filtering device when providing a warm-to-cold air flow direction.

[0050] Figure 3 shows a horizontal cross section of the one-way-flow pulse heat exchanging air filter and the alternating bidirectional air guide and air flow pattern through the parts.

[0051] Figure 4 shows a vertical cross section in the longitudinal direction of a further embodiment of the heat exchange filtering device when providing a warm-to-cold air flow direction.

[0052] Figure 5 shows a pair of heat exchange filtering devices installed in a window frame.

[0053] Detailed description

[0054] The present disclosure will now be described with reference to the accompanying drawings, in which preferred example embodiments of the disclosure are shown.

[0055] Figure 1A shows a perspective view of the heat exchange filtering device when providing a warm-to-cold air flow direction, and showing a longitudinal cross section cut on one side, according to an embodiment of the present disclosure.

[0056] The first aspect of present disclosure comprises an embodiment comprising an alternating bidirectional fan comprising an impeller 10, and a motor 3 for rotating the impeller 10, , a first side 11 and an opposite second side 12, an alternating bidirectional air guide 4, 4', 4” arranged radially outside the impeller 10, and an in-flow guide 5 arranged on the inflow side 7 of the alternating bidirectional fan 1, the alternating bidirectional air guide 4, 4', 4” and the in-flow guide 5 being rotationally connected.

[0057] There is an advantage by providing air guides changing the air flow independent of the axis, position and angular velocity of the motor and impeller that can operate continuously independent of air flow direction.

[0058] According to a further aspect the alternating bidirectional fan further comprising a one- way-flow air filter being rotationally connected to the impeller.

[0059] According to a further aspect of the alternating bidirectional fan, the one-way-flow air filter is a one-way-flow pulse heat exchange air filter.

[0060] Further embodiments comprising air filtering capacities and heat exchange capabilities are discussed below, but in its simplest most stripped down version the present disclosure provides for an alternating directional fan providing a bidirectional air flow. The alternating directional fan comprises only a motor, an impeller and a rotating house comprising the air flow guides 4, 4', 4”, 5. The air flow guide provides for a rapid switch altering the air flow between a first direction through the alternating directional fan to a second direction in the opposite direction. The switching time may be as low as less than 1 second, and even as low as less than 0,3 seconds. The quick change is facilitated by that the air flow guides rotate to change the air flow directions, but the motor and impeller remains in its original position. This operation is different from other comparable techniques which when one motor / rotor is used will alter the arrangement of the motor / rotor to facilitate a changed air flow direction. The motor and impeller will be arranged in one position only, and the impeller will rotate independent of the air flow guides 4, 4', 4", 5 in the same direction irrespectively of the direction of the air flow through the alternating directional fan. The arrangement of the air flow guides being rotationally connected to the motor and impeller, provides for this unique feature. The air flow guides 4, 4', 4”, 5 are explained further below in combination with filters and / or heat exchange filter, but the filters and heat exchange filter are not mandatory for achieving the unique bidirectional air flow. Therefore the present disclosure also defines this as a standalone feature solving problems related to air exchange. In the following description the alternating bidirectional fan will be described as a heat exchange air filtering device, due to the optional air filtering and / or heat exchange capabilities that are added to the basic version of the alternating bidirectional fan.

[0061] It is also in the following described a warm side instead of the first side and a cold side instead of the second side mentioned above.

[0062] Thus, a further aspect of this disclosure shows a heat exchange air filtering device 1 comprising: a one-way-flow pulse heat exchanging air filter 2, and a motor 3 for rotating the one-way-flow pulse heat exchanging air filter 2, the heat exchange air filtering device 1 further comprising: a warm side 11 and an opposite cold side 12, and the one-way-flow pulse heat exchanging air filter 2 operating as a first pulsed heat exchanger, further comprising: an alternating bidirectional air guide 4, 4', 4” arranged radially outside the one-way-flow pulse heat exchanging air filter 2, and an in-flow guide 5 arranged on the inflow side 7 of the one- way-flow pulse heat exchanging air filter 2, the alternating bidirectional air guide 4, 4', 4” and the in-flow guide 5 being rotationally connected.

[0063] When the one-way-flow pulse heat exchanging air filter 2 rotates, clockwise rotation is used as an "example only" in the figures, the air flow 7 from the warm side 11 over the top of the one-way-flow pulse heat exchanging air filter 2 and into the center inflow duct 30 of the one-way-flow pulse heat exchanging air filter 2, such that air flows through the filter 9 radially from the inside to the outside. The rotation of the one-way-flow pulse heat exchanging air filter 2 pushes the air out through the filter 9 and into the alternating bidirectional air guide 4, 4', 4”. As explained further below the alternating bidirectional air guide 4, 4', 4” collects the air flowing out of the filter 9 from the first part of a snail house 4' and guides the air flow out through the opening / lamellas at the second part of the snail house 4”.

[0064] The one-way-flow pulse heat exchanging air filter 2 may further comprise one or more of: the one-way-flow air filter is a rotating pleated filter 9, and the impeller is a rotationally connected morphed impeller 10. Pleated filter 9 is provided to increase both thermal and filtering efficiency. The impeller may be comprised of air foils having a morphed axial to radial shape to increase fan efficiency and reduce noise.

[0065] The alternating bidirectional air guide 4, 4', 4” may advantageously be constructed with a first part of a snail house 4' radially expanding air duct 51 - 51', and a second part of the snail house comprising one of:

[0066] - an opening 41, or

[0067] - a radially decreasing air duct 52-52' comprising one or more of:

[0068] - a second pulsed heat exchanger 4", and

[0069] - a mesh 42 for eddie / turbulence reduction.

[0070] As shown in figure 3 it is exemplified how the flow builds up between the clockwise rotating 50 one-way-flow pulse heat exchanging air filter 2 and the first part of a snail house 4'. The first part of a snail house 4' provides a barrier for the air flow, it is non-permeable. When the air flows from warm-to-cold side the first part of a snail house 4' is arranged towards the warm side of the heat exchange air filtering device 1, effectively blocking any air from returning to the warm side. When the one-way-flow pulse heat exchanging air filter 2 rotates in the clockwise direction 50 , the air moves radially out 8 of the filter 9 in the one- way-flow pulse heat exchanging air filter 2 to the space between the outside of the one-way- flow pulse heat exchanging air filter 2 and the inside of the snail house 4', 4'' and there flows in the clockwise 50 direction with a spinning flow pattern driven by the rotation of the one- way-flow pulse heat exchanging air filter 2.

[0071] The radially expanding air duct 51 - 51' accommodate the air and preserve the tangential velocity of the incoming air flow.

[0072] When the air enters the decreasing air duct 52-52' the air escapes through the opening 41 when no mesh 42 or second pulsed heat exchanger 4'' is present, or through the second pulsed heat exchanger 4'' and / or the mesh 42 when present. The second pulsed heat exchanger 4'' typically is comprised of a lightweight pulse heat exchanger. In the embedment where the second pulsed heat exchanger 4” is present, the decreasing air duct 52-52' provides for an even distribution of air through the second pulsed heat exchanger 4”.

[0073] The second pulsed heat exchanger 4” advantageously comprise an array of lamellas arranged perpendicular, or slightly tilted, to the air flow and in addition bent towards the incoming air flow with a low angle of attack for converting dynamic pressure to static pressure that in turn overcome the pressure resistance of the second pulsed heat exchanger 4”. All heat exchange are associated with a pressure loss, but the system according to present disclosure use spin energy to drive flow through the pulsed heat exchanger without substantially any flow-reducing pressure loss.

[0074] The flow path through the device travels through one or more porous media. The principle of the one-way-flow pulse heat exchanging air filter 2 utilizes the fact that heat pulses from shifting inflow temperatures travel substantially slower through the porous media than the air carrying the heat and driving the heat pulse forward. By alternating the warm and cold inflow with a 180 degree phase shift synchronized with the heat pulse travel time through the one-way-flow pulse heat exchanging air filter 2, heat stored in the porous media is transferred to the fresh cold incoming air, and sent back indoors, hence preserving energy. By using the heat capacity of the porous filter a thermal efficiency of more than 50% can be achieved without the extra energy consumption traditional heat exchanger would need for the operation. By combining a further lightweight pulse heat exchanger in series a thermal efficiency of more than 60% can be achieved without the extra energy consumption traditional heat exchanger would need for the operation. For even further increase of the thermal efficiency the pulsating air pumping action of the present disclosure can be combined with a traditional push pull heat exchanger 15. The fact that the efficiency is already lifted to above 60 % enables energy savings previously not possible, hence 80-90 % efficiency is easily achieved. The principle also allows for substantially smaller systems to achieve high filtration grade and at the same time high thermal efficiency.

[0075] The heat exchange air filtering device 1 may further comprise: a static air flow guide 6 being constructed to: - separate the air in-flow 13 from the following out-flow 14' at the warm side 11, of the one-way-flow pulse heat exchanging air filter 2.

[0076] Figure 1A show one side of the heat exchange air filtering device 1. The heat exchange air filtering device 1 may be symmetrical in design, and regarding the static air flow guide 6, this may also be symmetrical in design, and the embodiment shown have two openings 6' for exit air flowing from the one-way-flow pulse heat exchanging air filter 2 when air flow in cold- to-warm side. The figure 1A shows a warm-to-cold flow direction phase, and in this phase the air flows from the warm side over the static air flow guide 6. The static air flow guide 6 blocks an air to enter anywhere else but over the top of the one-way-flow pulse heat exchanging air filter 2 and into the clockwise rotating filter 9. The static air flow guide 6 is not limited to the form as described above, but can have other forms serving the same purpose.

[0077] The static air flow guide 6 ensures that air flows do not mix easily when the air flow phases shift.

[0078] The in-flow guide 5 is arranged on the opposite side of the air in-flow 30 to the position of the first part of the snail house 4' of the alternating bidirectional air guide 4, 4', 4” for guiding air into the one-way-flow pulse heat exchanging air filter 2, such that when the alternating bidirectional air guide 4, 4', 4” is in a first locked position the air flows from the warm side 11 of the heat exchange air filtering device 1 into the one-way-flow pulse heat exchanging air filter 2 and out of the one-way-flow pulse heat exchanging air filter 2 to the cold side 12 of the heat exchange air filtering device 1, and when the alternating bidirectional air guide (4, 4', 4”) is in a second locked position, cold-to-warm flow direction phase as shown in figure IB, the air flows from the cold side 12 of the heat exchange air filtering device 1 into the one-way-flow pulse heat exchanging air filter 2 and out of the one-way-flow pulse heat exchanging air filter 2 to the warm side 11 of the heat exchange air filtering device 1.

[0079] In the figures of present invention, the in-flow guide 5 and the alternating bidirectional air guide 4, 4', 4” are rotationally connected, and in a radial position the in-flow guide 5 is arranged radially opposite the first part of the snail house 4' of the alternating bidirectional air guide 4, 4', 4”. In effect, as shown in figure 1A, when the alternating bidirectional air guide 4, 4', 4” is in a first locked position, the in-flow guide 5 block any air flow from passing over the one-way-flow pulse heat exchanging air filter 2 without entering into the one-way-flow pulse heat exchanging air filter 2 on its way in the warm-to-cold direction through the heat exchange air filtering device 1.

[0080] When the alternating bidirectional air guide 4, 4', 4” is in a second locked position, the in-flow guide 5 block any air flow from passing over the one-way-flow pulse heat exchanging air filter 2 without entering into the one-way-flow pulse heat exchanging air filter 2 on its way in the cold-to-warm direction through the heat exchange air filtering device 1.

[0081] The alternating bidirectional air guide 4, 4', 4” and the in-flow guide 5 rotates, as exemplified in the figures, in a clockwise direction when changing from the first locked position to the second locked position, and thus alternating an air flow between a warm-to- cold flow direction phase 13, 13' and a cold-to-warm flow direction phase 14, 14' through the alternating bidirectional fan (1).

[0082] In present disclosure there is envisaged one warm side and one cold side, with closed side walls. It is within the inventive concept of present disclosure to have more than one cold side, and more than one warm side with corresponding sections of the heat exchange air filtering device 1 accommodated to such multiple warm and cold sides (not shown).

[0083] The heat exchange air filtering device 1 comprises a rotation control device (not shown) for controlling an alternating duty cycle of the heat exchange air filtering device 1, and a controller (not shown), controlling the rotation control device. Typically there is two duty cycles, earlier described as: air flow in warm-to-cold flow direction phase and air flow in cold- to-warm flow direction phase.

[0084] The rotation control device 40 is arranged to lock-step the alternating bidirectional air guide 4, 4', 4'' and the rotationally connected in-flow guide 5 between the two duty cycles such that in the first duty cycle the in-flow guide 5 is located towards the cold side, and in the second duty cycle the in-flow guide 5 is located towards the warm side. The controller 41 may comprise communication means for communicating and synchronizing duty cycles with paired or other heat exchange air filtering devices 1.

[0085] Sensors, for sensing any of temperature, CO2, VOC, humidity or other, or other computing resources may provide input for either of the rotation control device and / or the controller controlling the duty cycles, or the motor controlling the RPM of the one-way-flow pulse heat exchanging air filter 2, and can thus be dependent on many different scenarios. Alternatively may a remote computing system be connected and define the duty cycle and / or the RPM of the one-way-flow pulse heat exchanging air filter 2 as a result of other sensor data and / or time / season / environment / case - dependent schedules.

[0086] The lock-step motion 50' is provided by one of: the momentum 8 of the spinning air flow exiting the one-way-flow pulse heat exchanging air filter 2, or an actuator (not shown).

[0087] The heat exchange air filtering device 1 may further comprise: a static push-pull heat exchanger 15 arranged at the cold 12 and / or the warm 11 side of the one-way-flow pulse heat exchanging air filter 2. Such static push-pull heat exchanger 15 when arranged at the cold 12 side of the heat exchange air filtering device 1 is specifically advantageous in combination with the one-way-flow pulse heat exchanging air filter 2 and the optional second pulsed heat exchanger 4”. Summed up the heat exchange then is provided in three steps:

[0088] 1. Filter pulse heat exchanger through the one-way-flow pulse heat exchanging air filter 2 that spins 50' continuously.

[0089] 2. Pulse heat exchanger through the second pulsed heat exchanger 4''.

[0090] 3. Static push-pull heat exchanger 15 arranged on an accompanying chassis or arranged in a conduit in which the heat exchange filtering devices 1 is arranged.

[0091] The principle of present disclosure allows for substantially smaller systems to achieve high filtration grade and at the same time high thermal efficiency. The second aspect of this disclosure shows a system for ventilating the air in a room with reduced heat loss, the system comprising: two or more alternating bidirectional fans as described in the first aspect, and any of the two or more alternating bidirectional fans 1 operating in an antiphase pattern with any other of the two or more alternating bidirectional fans 1.

[0092] In one embodiment the alternating bidirectional fan 1 further comprising a one-way-flow air filter 2 being rotationally connected to the impeller 10.

[0093] In an even further embodiment the one-way-flow air filter 2 is a one-way-flow pulse heat exchange air filter 2.

[0094] In one embodiment as shown in figure 5 the heat exchange air ventilation function will be divided in two heat exchange filtering devices 1 with optional separate electronics. These heat exchange filtering devices 1 may be located on each side of the window, optionally with click on sound dampers. Working in anti-phase, when one heat exchange filtering device 1 operates in warm-to-cold 13, 13' air flow direction, the other works in the opposite direction, cold-to- warm 14, 14' air flow direction, as shown in the figure. This way there will be a pressure alignment on the warm side. In one operating mode the heat exchange filtering devices 1 could be operating in a locked position, not providing heat exchange, for example in summertime.

[0095] In a further embodiment wherein a window comprises trickle vents, the heat exchange filtering devices 1 may easily be adapted for retrofitting to any side of the trickle vents (not shown). In such embodiments for an even more compact retrofit version the push-pull heat exchanger 15 may be arranged on the opposite side of the trickle vents (not shown).

[0096] The anti-phase pattern may be pre-configurable or dynamically configurable.

[0097] The person skilled in the art realizes that the present disclosure is not limited to the preferred embodiments described above. The person skilled in the art further realizes that modifications and variations are possible within the scope of the appended claims. Additionally, variations to the disclosed embodiments can be understood and effected by the skilled person in practicing the claimed disclosure, from a study of the drawings, the disclosure, and the appended claims.

Claims

Claims1. An alternating bidirectional fan (1) comprising: an impeller (10), and a motor (3) for rotating the impeller (10), a first side (11) and an opposite second side (12), and the alternating bidirectional fan (1) being c h a r a c t e r i z e d b y comprising: an alternating bidirectional air guide (4, 4', 4") arranged radially outside the impeller (10), and an in-flow guide (5) arranged on the inflow side (7) of the alternating bidirectional fan (1), the alternating bidirectional air guide (4, 4', 4") and the in-flow guide (5) being rotationally connected, wherein: the alternating bidirectional fan (1) is configured to alternate an air flow through the alternating bidirectional fan (1) by shifting the alternating bidirectional air guide (4, 4', 4") and the in-flow guide (5) between a first position and a second position.

2. The alternating bidirectional fan (1) according to claim 1, further comprising a one-way-flow air filter (2) being rotationally connected to the impeller (10).

3. The alternating bidirectional fan (1) according to claim 2, wherein the one-way-flow air filter (2) is a one-way-flow pulse heat exchange air filter (2).

4. The alternating bidirectional fan (1) according to claim 2 or 3, further comprising one or more of: the one-way-flow air filter (2) is a rotating pleated filter (9), and the impeller (10) is a rotationally connected morphed impeller.

5. The alternating bidirectional fan (1) according to any one of claim 1 to 4, wherein the alternating bidirectional air guide (4, 4', 4") being constructed with a first part of a snail house (4') comprising a radially expanding air duct (51, 51"), and a second part of the snail house (4") comprising one of:- an opening (41), or- a radially decreasing air duct (52, 52") comprising one or more of: o a second pulsed heat exchanger (4"), and o a mesh (42) for eddie / turbulence reduction.

6. The alternating bidirectional fan (1) according to any one of claim 1 to 5, further comprising: a static air flow guide (6) being constructed to: separate the air in-flow (13) when the alternating bidirectional air guide (4, 4', 4") and the inflow guide (5) is in the first position from the next phase out-flow (14') when the alternating bidirectional air guide (4, 4', 4") and the in-flow guide (5) is in the second position at the first side of the one-way-flow pulse heat exchanging air filter (2).

7. The alternating bidirectional fan (1) according to claim 5 or 6, wherein the in-flow guide (5) is arranged on the opposite side of the air in-flow (30) to the position of the first part of the snail house (4') of the alternating bidirectional air guide (4, 4', 4") for guiding air into the one-way-flow pulse heat exchanging air filter (2), such that: when the alternating bidirectional air guide (4, 4', 4") is in a first locked position the air flows from the first side (11) of the air filtering device (1) into the one-way-flow pulse heat exchanging air filter (2) and out of the one-way-flow pulse heat exchanging air filter (2) to the second side (12) of the air filtering device (1), and when the alternating bidirectional air guide (4, 4', 4") is in a second locked position the air flows from the second side (12) of the air filtering device (1) into the one-way-flow pulse heat exchanging air filter (2) and out of the one-way-flow pulse air filter (2) to the first side (11) of the air filtering device (1).

8. The alternating bidirectional fan (1) according to claim 7, further comprising a rotation control device (40) for controlling an alternating duty cycle of the air filtering device (1) , and a controller, controlling the rotation control device, wherein the rotation control device is arranged to lock-step the alternating bidirectional air guide (4, 4', 4") and the rotationally connected in-flow guide (5), and the lock-step motion is provided by one of:- the momentum (8) of the spinning air flow exiting the one-way-flow air filter (2), or- an actuator.

9. The alternating bidirectional fan (1) according to any one of the previous claims, further comprising: a static push-pull heat exchanger (15) arranged at the second (12) and / or the first (11) side of the one-way-flow pulse heat exchanging air filter (2).10.A system for ventilating the air in a room, the system comprising:- two or more alternating bidirectional fans (1) as described in any one of claim 1 to 9, and- any of the two or more alternating bidirectional fans (1) operating in an antiphase pattern with any other of the two or more alternating bidirectional fans (1) .11.The system according to claim 10, wherein the alternating bidirectional fan (1) further comprising a one-way-flow air filter being rotationally connected to the impeller (10).12.The system according to claim 11, wherein the one-way-flow air filter is a heat exchange air filtering device (1).13.The system according to any one of claim 10 to 12, wherein the antiphase pattern are pre- configurable or dynamically configurable.

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