Device for exchanging thermal energy with ambient air

Abstract

The invention relates to a device for exchanging thermal energy with ambient air, comprising at least one heat exchanger (12; 162, 164; 202) through which an air flow can flow and which is assigned an axial fan (16; 166, 168; 208) for conveying the air flow through the heat exchanger and an outflow housing (40; 170, 172; 210) receiving the air flow, wherein the outflow housing has an air outlet opening (46) for discharging the air flow into the environment. In order to develop the device in such a way that the outflow of the axial fan 16; 166; 168; 208) can be deflected transverse to the outlet direction of the axial fan with minimal flow losses, according to the invention, the outflow housing (40; 170; 172; 210) forms an air-receiving space (41) axially offset to an impeller wheel (24) and a motor (26) of the axial fan (16; 166, 168; 208), which receives the conveyed air flow over the entire cross-section of the impeller wheel (24) and the motor (26) and through which the fan rotational axis (28) engages, and wherein the outflow housing covers the impeller wheel (24) and the motor (26) when viewed from the rear and is designed and configured to supply the conveyed air flow with a directional component of the air outlet opening (46) tangential to a swirling movement imposed on the air flow by the axial fan.

Description

[0001] DEVICE FOR EXCHANGE OF HEAT ENERGY WITH THE AMBIENT AIR

[0002] The invention relates to a device for exchanging thermal energy with the ambient air, comprising at least one heat exchanger through which an air flow can flow, to which an axial fan for conveying the air flow through the heat exchanger and an outflow housing receiving the air flow conveyed by the axial fan on the outflow side are assigned, wherein the axial fan has a motor and an impeller with blades which can be driven by the motor to rotate about an axis of rotation, and wherein the outflow housing has an air outlet opening for discharging the air flow to the environment.

[0003] Devices with a heat exchanger through which an air flow can flow, an axial fan for conveying the air flow through the heat exchanger and with an outflow housing which receives the air flow conveyed by the axial fan on the downstream side and has an air outlet opening for discharging the air flow to the environment are used, for example, in heat pumps and air conditioning systems in which the heat exchanger assumes the function of an evaporator of a refrigerant flowing through the heat exchanger in heating mode and the function of a condenser in cooling mode.

[0004] Such devices are also used in the electronics sector to cool electronic components. The heat exchanger is designed in the form of a heat sink through which the air flow can flow and on which the electronic components are arranged. In order to expose the heat sink to the air flow conveyed by the axial fan, the axial fan is usually selected to be large enough to almost completely cover the surface of the heat sink. Compared to radial fans, axial fans have the advantage of a large intake area and thus enable a uniform air flow through the heat exchanger. However, axial fans have the disadvantage that the conveyed volume flow decreases even with a moderate increase in back pressure. For this reason, axial fans often have a free outflow without obstructions.In many cases, however, it is necessary to divert the airflow by 90° for discharge to the environment downstream of the axial fan. To minimize pressure losses, the discharge housing often features a box-like shaft whose width is at least equal to the diameter of the axial fan. This results in a significant increase in the size of the device, and despite the considerable size, pressure losses often cannot be avoided.

[0005] For heat pumps used for building or swimming pool heating, installation in the ground is often preferred over installation in a basement or outdoor space due to space requirements. In such cases, the return of the airflow to the environment requires an exhaust housing, which must have minimal flow resistance despite the strong air deflection to avoid a noticeable reduction in the delivered flow rate.

[0006] In the electronics sector, too, it is advantageous to increase the cooling performance, especially of high-performance processors, by directing the outflow of the axial fan to an air outlet opening via an outflow housing with a small installation space and minimal pressure loss, thus preventing internal backflow, a so-called thermal short circuit.

[0007] The object of the present invention is therefore to further develop a device of the type mentioned at the outset such that the outflow of the axial fan can be deflected transversely to the outlet direction of the axial fan with the lowest possible flow losses. This object is achieved according to the invention in a device of the generic type in that the outflow housing forms an air intake chamber axially offset from the impeller and the motor of the axial fan, which receives the conveyed air flow across the entire cross-section of the impeller and the motor and is penetrated by the axis of rotation of the axial fan, wherein the outflow housing covers the impeller and the motor like a hood in a rear view, and wherein the outflow housing is set up and designed to feed the conveyed air flow to the air outlet opening with a directional component that is tangential to a swirl movement imposed on the air flow by the axial fan.

[0008] The device according to the invention has an outflow housing which receives the air flow conveyed by the axial fan on the downstream side and feeds it to an air outlet opening through which the air flow can be released into the environment. The outflow housing forms an air intake chamber, axially offset from the impeller and motor of the axial fan, which absorbs the air flow conveyed by the axial fan across the entire cross-section of the impeller and motor and is penetrated by the rotational axis of the axial fan. In a rear view looking along the rotational axis, the outflow housing covers the impeller and motor like a hood. The air flow conveyed by the axial fan can thus be absorbed by the outflow housing over a large area and consequently with low loss across the entire cross-section of the impeller and motor.

[0009] Under the action of the axial fan, the conveyed air flow is subjected to a swirling motion around the rotational axis of the axial fan. According to the invention, the air flow is supplied to the air outlet opening with a tangential directional component relative to the swirling motion. The swirling motion of the air flow is thus utilized to deflect the air flow by 90°. Due to the imposed swirl, the air flow, which is supplied to the exhaust housing over a large area across the entire cross-section of the impeller and motor, performs a loop-like movement within the hood-like exhaust housing and is fed to the air outlet opening essentially in a tangential direction. This creates a parallel flow in the area of ​​the air outlet opening, which evenly fills practically the entire cross-section of the air outlet opening, with the air flow exhibiting hardly any residual swirl.The air flow is thus redirected with very low flow losses.

[0010] Compared to a conventional 90° elbow with an outlet diameter corresponding to the diameter of the axial fan's impeller, the size of the exhaust housing can be kept significantly smaller. In particular, the axial dimension of the exhaust housing relative to the rotation axis can be significantly reduced, so that the device according to the invention has a very compact design. Furthermore, a much more uniform airflow velocity distribution can be achieved in the area of ​​the air outlet opening, which can further reduce pressure losses.

[0011] For optimal flow, the axial dimension of the exhaust housing can be adjusted to the existing ratio of swirl to axial velocity of the airflow, which depends on the impeller blades used and the selected operating point of the axial fan. The size of the air outlet opening influences the outlet velocity of the airflow. Increasing the size creates a diffuser effect, slowing the airflow. Reducing the size creates a nozzle effect, thus accelerating the airflow. The outlet velocity can, for example, be selected just large enough to reliably prevent backflow to the inlet of the heat exchanger and thus a thermal short circuit. This enables very high energy efficiency of the device according to the invention.

[0012] Preferably, the air outlet opening is arranged downstream of the axial fan in a region of the outflow housing that is laterally offset from a center plane of the axial fan, wherein the center plane is aligned coaxially with the axis of rotation of the axial fan, and wherein the blading of the impeller rotates in this laterally offset region towards the air outlet opening in a rear view of the outflow housing. In a rear view of the outflow housing looking along the axis of rotation, the center plane of the axial fan divides the impeller into two halves. The air outlet opening is arranged downstream of the axial fan on the side of the center plane on which the blading of the impeller rotates towards the air outlet opening when rotating about the axis of rotation in the rear view of the outflow housing.As a result, the air flowing on this side of the center plane moves essentially tangentially toward the air outlet opening, while the air flowing on the opposite side of the center plane moves within the hood-like exhaust housing in a loop-like motion toward the air outlet opening. This creates a parallel flow in the air outlet opening that evenly fills virtually the entire cross-section of the air outlet opening and exhibits virtually no residual swirl.

[0013] In a preferred embodiment of the invention, the extension of the air outlet opening transverse to the rotational axis is a maximum of 1.9 times the outer radius of the impeller. This helps to direct the air flow essentially tangentially to the air outlet opening.

[0014] It is advantageous if the air outlet opening extends transversely to the axis of rotation to at least 0.5 times the outer radius of the impeller. With this design of the invention, the air flow is accelerated in the area of ​​the air outlet opening and released into the environment at a higher speed. This reliably counteracts backflow to the inlet of the heat exchanger, thus causing a thermal short circuit.

[0015] It is advantageous if the exhaust housing has an air outlet nozzle that defines the air outlet opening. The air outlet opening can be oriented tangentially to the swirling motion of the airflow, thereby creating a particularly uniform parallel flow and keeping flow losses to a minimum.

[0016] The air outlet nozzle can be designed to widen or taper in the direction of flow. A widened or tapered nozzle creates a diffuser effect, slowing the flow, while a tapered nozzle creates a jet effect, accelerating the flow. The choice of widened or tapered nozzle for the air outlet nozzle thus allows you to specify the speed at which the air flow is released into the environment.

[0017] In a preferred embodiment of the invention, the exhaust housing has a rear wall opposite the axial fan, which has at least one rear wall section inclined to the axis of rotation of the axial fan, over which the distance of the rear wall from the axial fan increases. It is advantageous if the at least one rear wall section, which is inclined to the axis of rotation, is arranged on the side of a center plane aligned coaxially to the axis of rotation, on which the flowing air rotates in a loop-like motion. In the direction of rotation, the continuous supply of air from the axial fan leads to an increase in the mass flow.To counteract the associated increase in flow velocity, the at least one rear wall section, which increases the distance between the rear wall and the axial fan, can be used to increase the flow cross-section of the airflow, thereby counteracting an increase in flow velocity. This can reduce flow losses.

[0018] It is advantageous if the exhaust housing has a circumferential side wall. This further reduces flow losses and prevents dirt deposits within the exhaust housing. It is particularly advantageous if the side wall of the exhaust housing widens with increasing distance from the axial fan. The side wall thus forms a kind of cone that opens in the direction away from the axial fan.

[0019] It is advantageous if the side wall transitions seamlessly into the rear wall of the exhaust housing via a rounded section. The rounded section can vary in radius, i.e., narrow or widen. The rounded section supports the low-loss redirection of the airflow toward the air outlet.

[0020] It is particularly advantageous if the rear wall widens spirally in the circumferential direction. This spiral widening allows for a particularly low-loss airflow supply to the air outlet opening, deflecting the airflow by 90°. This counteracts an increase in airflow velocity despite the linearly increasing volume flow from the impeller in the circumferential direction.

[0021] In an advantageous embodiment of the invention, the axial fan comprises a housing defining an inlet channel and an outlet channel, wherein the inlet channel is arranged upstream of the impeller and the outlet channel surrounds the impeller in the circumferential direction. The air flow can be supplied to the impeller via the inlet channel. The inlet channel can be directly connected to the heat exchanger. The outlet channel surrounds the impeller and, in combination with the impeller blades, defines the air flow on the downstream side of the axial fan.

[0022] It is advantageous if the inlet duct extends to a bulkhead having an opening to which the outlet duct is connected. The bulkhead makes it possible to separate the inlet side of the axial fan from its outlet side, thereby preventing internal backflow and thus thermal short circuits. In an advantageous embodiment of the invention, the outlet duct forms a constriction adjacent to the opening in the bulkhead, to which an annular wall is connected. This constriction reduces the flow cross-section of the airflow and thus increases its speed, i.e. the constriction forms an inlet nozzle. The annular wall, in combination with the blading of the impeller, defines the axial movement of the airflow. The annular wall is preferably cylindrical or conical.

[0023] The exhaust housing can be arranged to adjoin the bulkhead of the fan housing and circumferentially surround the fan housing's exhaust duct. In such a configuration, the fan housing is submerged in the exhaust housing.

[0024] It is advantageous if the heat exchanger is flat and the axial fan's rotation axis is aligned at an angle to the heat exchanger. The angled orientation of the rotation axis supports the low-loss redirection of the air flow toward the air outlet.

[0025] In a preferred embodiment of the invention, the axis of rotation of the axial fan is aligned at an angle of maximum 30°, in particular 5° to 10°, to the surface normal of the heat exchanger.

[0026] In an advantageous embodiment of the invention, the exhaust housing has a flow guide element directed radially inward relative to the rotational axis of the axial fan, which is arranged in the transition area between an air outlet nozzle and a side wall of the exhaust housing. The flow guide element allows the discharged volume flow to be separated from the loop-shaped circulating volume flow in a simple design. This improves the parallel flow in the area of ​​the air outlet opening.

[0027] The flow guide element can, for example, be designed in a tongue-like manner. The device according to the invention can be provided with a single heat exchanger, to which an axial fan and an exhaust housing are assigned. The axial fan can generate an air flow flowing through the heat exchanger, which can be discharged to the environment via the air outlet opening of the exhaust housing.

[0028] Alternatively, it can be provided that the device according to the invention has a plurality of heat exchangers, in particular two heat exchangers, each of which is assigned an axial fan and an outflow housing, wherein the air flows conveyed by the axial fans can be fed via the air outlet openings of the outflow housings to a common air outlet duct, via which the air flows can be discharged to the environment, wherein the air outlet openings are aligned obliquely to one another. For example, it can be provided that the device has two heat exchangers arranged one above the other or next to one another, each of which can be flowed through by an air flow generated by an axial fan assigned to the respective heat exchanger, wherein the air flow can be fed to a respective outflow housing, from which the air flow can be fed to the common air duct via the respective air outlet opening.

[0029] The air outlet openings of the outflow housings can each be defined by an air outlet nozzle, whereby the air outlet nozzles of the two outflow housings are aligned at an angle to each other.

[0030] It is particularly advantageous if the two exhaust housings are identically designed and aligned differently with respect to the shared air outlet duct. When the device is installed, the two exhaust housings can be rotated to a specific position relative to the respective fan rotation axis, so that their air outlet nozzles open into the shared air outlet duct. It is advantageous if the exhaust housing is mounted on a base plate of the axial fan so that it can rotate about its rotation axis.

[0031] The invention also relates to the use of the device explained above in a heat pump or air conditioning system or for cooling electronic components.

[0032] The following description of preferred embodiments of the invention serves to explain it in more detail in conjunction with the drawings. They show:

[0033] Figure 1: an exploded view of a first embodiment of a device for exchanging thermal energy with the ambient air;

[0034] Figure 2: a perspective view of an outflow housing of the device from Figure 1 with exemplary streamlines of an air flow;

[0035] Figure 3: a side view of a second embodiment of a device for exchanging thermal energy with the ambient air;

[0036] Figure 4: a perspective view of the device from Figure 3;

[0037] Figure 5: a perspective view of a third embodiment of a device for exchanging thermal energy with the ambient air;

[0038] Figure 6: a side view of the device from Figure 5;

[0039] Figure 7: a rear view of the device from Figure 5; Figure 8: a perspective view of an outflow housing of the device from Figure 5, looking obliquely from below at a flow inlet;

[0040] Figure 9: a side view of a fourth embodiment of a device for exchanging thermal energy with the ambient air;

[0041] Figure 10: a perspective view of a fifth embodiment of a device for exchanging thermal energy with the ambient air;

[0042] Figure 11: a rear view of the device from Figure 10;

[0043] Figure 12: a rear view of a sixth embodiment of a device for exchanging thermal energy with the ambient air;

[0044] Figure 13: a perspective view of a seventh embodiment of a device for exchanging thermal energy with the ambient air.

[0045] Figure 1 shows a schematic exploded view of a first advantageous embodiment of a device according to the invention for exchanging thermal energy with the ambient air, which is designated overall by the reference numeral 10. The device 10 has a conventional flat heat exchanger 12 with a fluid line 14 through which a fluid can flow to heat or cool the fluid, whereby an exchange of thermal energy with the ambient air takes place. For this purpose, the heat exchanger 12 can be passed through by an air flow generated by an axial fan 16. The axial fan 16 adjoins the heat exchanger 12 in the flow direction of the air flow and has a fan housing 18 which forms an inflow channel 20 with a rectangular cross-section and an outflow channel 22 with a circular cross-section.In addition, the axial fan 16 has an impeller 24, which can be rotated about a rotational axis 28 by a motor 26. The impeller 24 has a plurality of blades 30 for conveying the air flow. The impeller 24 is rotatably mounted in the outflow duct 22, and the inflow duct 20 is arranged upstream of the impeller 24.

[0046] Starting from the heat exchanger 12, the inlet channel 20 extends to a bulkhead 32, which has an opening 33, to which a constriction 34 of the outlet channel 32 is connected. The constriction 34 forms an inlet nozzle. Adjoining the constriction 34 is an annular wall 36 of the outlet channel 32, which circumferentially surrounds the impeller 24. Viewed toward the motor 26, the impeller 24 rotates counterclockwise. The direction of rotation of the impeller 24 is illustrated in Figure 1 by the arrow 38.

[0047] The device 10 also has an outflow housing 40 which is connected to the axial fan 16 in the flow direction of the conveyed air flow and receives the air flow conveyed by the axial fan 16 on the outflow side.

[0048] The exhaust housing 40 is designed like a hood, forming an air intake chamber 41 axially offset from the impeller 24 and the motor 26, through which the rotational axis 28 passes. In a rear view along the rotational axis 28, the exhaust housing 40 covers the impeller 24 and the motor 26, whose motor axis (not shown in the drawing) is aligned coaxially with the rotational axis 28. The exhaust housing absorbs the air flow conveyed by the axial fan 16 over a large area across the entire cross-section of the impeller 24 and the motor 26.

[0049] The exhaust housing 40 is shown enlarged in Figure 2 together with the impeller 24 and the motor 26. The exhaust housing 40 has a cuboid-shaped housing body 42, which rests against the bulkhead 32 and surrounds the exhaust duct 22 as well as the impeller 24 and the motor 26. An air outlet nozzle 44 is connected to the top of the housing body 42, which defines an air outlet opening 46 of the exhaust housing 40. The air flow conveyed by the axial fan 16 can be discharged to the environment via the air outlet opening 46.

[0050] The air outlet nozzle 44 and the air outlet opening 46 are arranged in a region laterally offset from a center plane 48 of the outflow housing 40, shown in dash-dotted lines. The center plane is coaxial with the rotational axis 28 and, in the illustrated position of use of the device 10, is vertically aligned. The blades 30 of the impeller 24 rotate in this laterally offset region toward the air outlet opening 46 in a rear view of the outflow housing 40. The viewing direction in the rear view is illustrated in Figure 1 by the arrow 50.

[0051] Under the action of the axial fan 16, the conveyed air flow is imparted a swirling motion around the rotational axis 28. The arrangement of the air outlet nozzle 44 and the air outlet opening 46, which is laterally offset from the central plane 48, and the blading 30 of the impeller 24, which rotates in this laterally offset region relative to the air outlet opening 46 in a rear view of the outflow housing 40, results in the air flow conveyed by the axial fan 16 being fed to the air outlet opening 46 in this laterally offset region essentially in a tangential direction with respect to the swirling motion. On the side of the central plane 48 facing away from the air outlet nozzle 44 and the air outlet opening 46, the air flow executes a loop-like motion before flowing in an essentially tangential direction toward the air outlet opening 46.This creates a parallel flow in the air outlet nozzle 44 that evenly fills the entire cross-section of the air outlet nozzle 44 and exhibits hardly any residual swirl. To illustrate the air flow in the area of ​​the outflow housing 40, some flow lines a, b, c, d, and e are shown in dashed lines in Figure 2 as examples. The device 10 thus makes it possible to guide an air flow through the heat exchanger 12 in an axial direction relative to the axis of rotation 28 and to deflect the air flow in the outflow housing 40 by 90° using the swirl movement caused by the axial fan 16. This deflection is associated with very low flow losses, and the air flow in the area of ​​the air outlet opening 46 essentially forms a parallel flow.The low-loss deflection of the air flow within the discharge housing 40 is achieved even though the axial dimension of the discharge housing 40, i.e., its depth, is smaller than the dimension of the discharge housing 40 transverse to the rotation axis 28. The device 10 thus enables a low-loss deflection of the air flow by 90°, while the device 10 has a compact design. For a particularly low-loss deflection of the air flow, the depth of the discharge housing 40 can be adapted to the existing ratio of swirl to axial velocity of the air flow, which depends on the blades 30 used for the impeller 24 and the selected operating point of the axial fan 16.

[0052] Figures 3 and 4 schematically illustrate a second advantageous embodiment of a device according to the invention for exchanging thermal energy with the ambient air, the device being designated overall by reference numeral 60. For identical components, the same reference numerals are used in Figures 3 and 4, as well as in Figures 5 to 13 explained in more detail below, as in Figures 1 and 2. To avoid repetition, reference is made to the above explanations with regard to these components.

[0053] The device 60 shown in Figures 3 and 4 differs from the device 10 shown in Figures 1 and 2 by a hood-like outflow housing 62 having a cylindrical side wall 64 circumferentially surrounding the outflow duct 22 as well as the impeller 24 and the motor 26 of the axial fan 16, which extends in the axial direction from the bulkhead 32 of the axial fan 16 to a rear wall 66 opposite the axial fan 16, which has a first flat rear wall section 68 inclined to the axis of rotation 28 and a second flat rear wall section 70 inclined to the axis of rotation 28, over which the distance between the rear wall 66 and the axial fan 16 increases. The two rear wall sections 68, 70 adjoin an air outlet nozzle 72 of the outflow housing 62.

[0054] The air outlet nozzle 72 defines an air outlet opening 74 and, in a manner corresponding to the air outlet nozzle 44 explained above with reference to Figures 1 and 2, is arranged laterally offset from a center plane 75 aligned coaxially with the rotation axis 28. The center plane 75 is shown in dash-dotted lines in Figure 4. The first rear wall section 68 and the second rear wall section 70 are positioned on the side of the center plane 75 opposite the air outlet nozzle 72. The air outlet nozzle 72 extends with a nozzle rear wall 76 to the lower end of the outflow housing 62, wherein the nozzle rear wall 76 is inclined rearward on the side facing away from the axial fan 16, so that the flow cross-section of the air outlet nozzle 72 continuously widens in the flow direction.

[0055] The obliquely aligned rear wall sections 68, 70 expand the internal volume of the discharge housing 62 on the side of the center plane 75, on which the flowing air executes a loop-like movement, with the volume flow in this area continuously increasing in the circumferential direction due to the air continuously conveyed by the impeller 24. In order to achieve a substantially constant flow velocity despite the increase in the volume flow, the obliquely aligned rear wall sections 68, 70 are used, which cause an expansion of the internal volume of the discharge housing 62 in this area.On the side of the center plane 75 opposite the rear wall sections 68, 70, the blades 30 of the impeller 24 rotate toward the air outlet opening 74 in a rear view of the outflow housing 62, so that the air flow is supplied to the air outlet opening 74 essentially in a tangential direction relative to the swirling motion of the air flow, as already explained above with reference to Figures 1 and 2. The flow cross-section of the air outlet nozzle 72, which continuously increases in the flow direction, acts as a diffuser that slows the flow.

[0056] The device 60 thus enables a low-loss deflection of the air flow by 90° with a very compact design.

[0057] Figures 5 to 8 schematically illustrate a third advantageous embodiment of a device according to the invention for exchanging thermal energy with the ambient air, the device as a whole being designated by the reference numeral 90. The device 90 has a hood-like outflow housing 92 which, in contrast to the outflow housings 62 and 40 explained above, does not directly adjoin the bulkhead 32 of the axial fan 16. Instead, the outflow housing 92 adjoins the outflow duct 22 of the axial fan 16, having a side wall 94 which adjoins the outflow duct 22 and which continuously widens with increasing distance from the axial fan 16 and which, via a rounded portion 96, continuously merges into a rear wall 98 which widens spirally in the circumferential direction.

[0058] In the device 90, the axial fan 16 is inclined relative to the heat exchanger 12, i.e., the rotational axis 28 of the axial fan 16 is inclined at an angle a of a maximum of 30°, in particular at an angle a of 5 to 10° relative to the surface normal 100 of the flatly configured heat exchanger 12. The inclination of the axial fan 16 supports the low-loss deflection of the air flow into the air outlet nozzle 102 of the outflow housing 92, which defines an air outlet opening 104 and is arranged laterally offset from a center plane 106 aligned coaxially with the rotational axis 28. This is particularly evident in Figure 7.The absorption of the volume flow of the conveyed air from the axial fan 16, which increases linearly in the circumferential direction, is achieved by expanding the internal volume of the outflow housing 92 via the side wall 94, which continuously expands with increasing distance from the axial fan 16, and the rear wall 96, which continuously expands in the circumferential direction, so that a substantially constant flow velocity can be achieved despite the volume flow of the conveyed air increasing linearly in the circumferential direction.

[0059] In the device 90, the blades 30 of the impeller 24, in a rear view of the discharge housing 92, also rotate in the direction of the air outlet nozzle on the side of a center plane 106 (shown in dash-dotted lines in Figure 7), on which the air outlet nozzle 102 and the air outlet opening 104 are arranged, so that the air flow conveyed by the axial fan 16 can be fed to the air outlet opening 104 essentially in a tangential direction relative to the swirling movement of the air flow. On the opposite side of the center plane 106, the air moves in a loop-like manner and is then also fed to the air outlet nozzle 102 and the air outlet opening 104 essentially in a tangential direction.

[0060] The air outlet nozzle 102 has a wall flattening 112 between a nozzle rear wall 108 facing away from the axial fan 16 and a nozzle side wall 110 facing the center plane 106, which prevents an area with a lower flow velocity from forming in this area of ​​the air outlet nozzle 102.

[0061] In the transition area between the rounded portion 96 and the air outlet nozzle 102, the outflow housing 92 has a tongue-shaped, inwardly directed flow guide element 114, which ensures a precise separation of the discharged and circulating volume flow, wherein the discharged volume flow can reach the air outlet opening 104 via the air outlet nozzle 102 and the circulating volume flow executes a loop-like movement around the rotation axis 28. The separation of the discharged and circulating volume flow improves the parallel flow in the air outlet nozzle 102. Figure 9 schematically shows a fourth advantageous embodiment of a device according to the invention for exchanging thermal energy with the ambient air, the device as a whole being designated by the reference numeral 120.

[0062] The device 120 has a hood-like outflow housing 122, which extends with a front housing section 124 to the heat exchanger 12. The front housing section 124 surrounds the fan housing 18, but only a small amount of vibration is transmitted from the axial fan 16 to the outflow housing 122; instead, vibrations of the axial fan 16 are primarily absorbed by the heat exchanger 12.

[0063] With the exception of the front housing section 124, the outflow housing 122 is designed in the same way as the outflow housing 92 explained above, so that reference can be made to the above explanations in this regard.

[0064] Figures 10 and 11 schematically illustrate a fifth advantageous embodiment of a device according to the invention for exchanging thermal energy with the ambient air, the device as a whole being provided with the reference numeral 140. The device 140 has a hood-like outflow housing 142 which is largely identical in design to the outflow housing 92 explained above with reference to Figures 5 to 8. In contrast to the outflow housing 92, the outflow housing 142 has an air outlet nozzle 144 with a nozzle side wall 146 which is inclined to a central plane 148 aligned coaxially to the axis of rotation 28, so that the flow cross-section of the air outlet nozzle 144 is reduced in the flow direction and the flow velocity of the air flow in the air outlet nozzle 144 is thereby increased.

[0065] The air outlet nozzle 144 defines an air outlet opening 150, which, like the air outlet nozzle 144, is arranged laterally offset from the center plane 148, as already explained above. The extension of the air outlet opening 150 transverse to the rotational axis 28 is smaller than the outer radius of the impeller 24, so that a jet effect is created and the air flow conveyed by the axial fan 16 is ejected from the air outlet opening 150 at a considerable flow velocity.

[0066] Figure 12 schematically illustrates a sixth advantageous embodiment of a device according to the invention for exchanging thermal energy with the ambient air. The device is designated overall by reference numeral 160.

[0067] The device 160 has a first heat exchanger 162 and a second heat exchanger 164, which are arranged one above the other and each of which is assigned an axial fan 166 and 168, respectively, and a hood-like exhaust housing 170 and 172, respectively. The two heat exchangers 162, 164 are identically designed, and the two axial fans 166, 168 are also identically designed, as are the two exhaust housings 170, 172. The two exhaust housings 170, 172 each have an air outlet nozzle 174 and 176, respectively, which open into a common air outlet duct 178, through which the air streams conveyed by the two axial fans 166, 168 are discharged to the environment. The identically designed axial fans 166, 168 each have a center plane 180 or 182 shown in dash-dotted lines in Figure 12, to which the air outlet nozzles 174, 176 are arranged offset, as already explained in detail above.With reference to the rear view of the device 160 shown in Figure 12, the axial fans 166, 168 differ only in their rotational position relative to the respective fan rotation axis, so that the air flows can be fed to the common air outlet duct with low flow losses.

[0068] Figure 13 schematically shows a seventh advantageous embodiment of a device according to the invention for exchanging thermal energy with the ambient air, the device being designated by the reference numeral 200.

[0069] The device 200 differs from the previously explained embodiments essentially in that it has a heat exchanger 202 in the form of a heat sink 204. The heat sink 204 has fins 206 and serves to cool electronic components. The heat sink 18 can be flowed through by an air stream, which is conveyed by an axial fan 208 of the device 200 and fed to a hood-like exhaust housing 210 of the device 200. In the exhaust housing 210, the air stream is deflected by 90°, as already explained in detail above, and can be discharged via an air outlet nozzle 212 and an air outlet opening 214 to the environment or to an air duct 216 adjoining the air outlet nozzle 212. The air duct 216 is shown in dashed lines in Figure 13.

[0070] The axial fan 208 is connected on the downstream side to a base plate 218, which enables the outflow housing 210 to be mounted so that it can rotate about the axis of rotation of the axial fan 208, so that the outflow housing 210 can assume a predeterminable rotational position in which the air outlet nozzle 212 assumes a desired orientation.

[0071] In the exhaust housing 210, the air outlet nozzle 212 and the air outlet opening 214 are also offset from a center plane that is coaxial with the fan rotation axis, as already explained in detail above. The device 200 also enables an energy-efficient exchange of thermal energy with the ambient air, whereby the air flow conveyed by the axial fan 208 can be deflected by 90° with minimal flow losses.

Claims

PATENT CLAIMS Device for exchanging thermal energy with the ambient air, comprising at least one heat exchanger (12; 162, 164) through which an air flow can flow, to which an axial fan (16; 166, 168; 208) for conveying the air flow through the heat exchanger (12; 162, 164) and an outflow housing (40; 62; 92; 122; 142; 170, 172; 210) are assigned, which receives the air flow conveyed by the axial fan (16; 166, 168; 208) on the outflow side, wherein the axial fan (16; 166, 168; 208) has a motor (26) and an impeller (24) which can be driven by the motor (26) to rotate about an axis of rotation (28) and has a blade arrangement (30), and wherein the outflow housing (40; 62; 92; 122; 142; 170, 172; 210) has an air outlet opening (46; 74; 104; 150; 174, 176; 214) for discharging the air flow to the environment, characterized in that the outflow housing (40; 62; 92; 122; 142; 170, 172;210) axially offset from the impeller (24) and the motor (26) of the axial fan (16; 166, 168; 208) forms an air intake chamber (41) which receives the conveyed air flow over the entire cross section of the impeller (24) and the motor (26) and is penetrated by the rotational axis (28), wherein the outflow housing (40; 62; 92; 122; 142; 170, 172; 210) covers the impeller (24) and the motor (26) in a hood-like manner in a rear view and is arranged and designed to direct the conveyed air flow with a tangential directional component of the air outlet opening (46; 74; 104; 150; 174, 176; 214). Device according to claim 1, characterized in that the air outlet opening (46; 74; 104; 150; 174, 176; 214) downstream of the axial fan (16; 166, 168; 208) is arranged in a plane extending to a center plane (48; 106; 148; 180, 182) of the axial fan (16; 166, 168; 208) is arranged in a laterally offset region of the outflow housing (40; 62; 92; 122; 142; 170, 172; 210), wherein the center plane (48; 106; 148; 180, 182) is aligned coaxially to the axis of rotation (28), and wherein the blading (30) of the impeller (24) in this laterally offset region is arranged in a rear view of the outflow casing (40; 62; 92; 122; 142; 170, 172; 210) to the air outlet opening (46; 74; 104; 150; 174, 176; 214). Device according to claim 1 or 2, characterized in that the extension of the air outlet opening (46; 74; 104; 150; 174, 176; 214) transverse to the axis of rotation (28) is a maximum of 1.9 times the outer radius of the impeller (24). Device according to claim 3, characterized in that the extension of the air outlet opening (46; 74; 104; 150; 174, 176; 214) transverse to the rotation axis (28) is at least 0.5 times the outer radius of the impeller (24). Device according to one of the preceding claims, characterized in that the outflow housing (40; 62; 92; 122; 142; 170, 172; 210) has an air outlet nozzle (44; 72; 102; 174, 176; 212) that defines the air outlet opening (46; 74; 104; 150; 174, 176; 214). Device according to claim 5, characterized in that the air outlet nozzle (44; 72; 102; 174, 176; 212) widens or tapers in the direction of flow.Device according to one of the preceding claims, characterized in that the outflow housing (40; 62; 92; 122; 142; 170, 172; 210) has a counter-rotating axial fan (16; 166, 168; 208). overlying rear wall (66), which has at least one rear wall section (68, 70) inclined to the axis of rotation (28), over which the distance of the rear wall (16) from the axial fan (16) increases. Device according to one of the preceding claims, characterized in that the outflow housing (62; 92) has a side wall (64; 94) running in the circumferential direction. Device according to claim 8, characterized in that the side wall (94) widens with increasing distance from the axial fan (16). Device according to claim 8 or 9, characterized in that the side wall (94) merges continuously into a rear wall (98) of the outflow housing (92) via a rounded portion (96). Device according to claim 10, characterized in that the rear wall (98) widens spirally in the circumferential direction.Device according to one of the preceding claims, characterized in that the axial fan (16) has a fan housing (18) defining an inlet channel (20) and an outlet channel (22), wherein the inlet channel (20) is arranged upstream of the impeller (24) and the outlet channel (22) surrounds the impeller (24) in the circumferential direction. Device according to claim 12, characterized in that the inlet channel (20) extends to a bulkhead (32) having an opening (33) to which the outlet channel (22) is connected. Device according to claim 13, characterized in that the outflow channel (22) forms a constriction (34) adjoining the opening (33) in the bulkhead (32), to which an annular wall (36) is connected. Device according to claim 13 or 14, characterized in that the outflow housing (40) adjoins the bulkhead (32) and surrounds the outflow channel (22) in the circumferential direction. Device according to one of the preceding claims, characterized in that the heat exchanger (12) is flat and the axis of rotation (28) is aligned obliquely to the heat exchanger (12). Device according to claim 16, characterized in that the axis of rotation (28) is aligned at an angle of maximum 30° to the surface normal (100) of the heat exchanger (12).Device according to one of the preceding claims, characterized in that the outflow housing (92) has a flow guide element (114) which is directed inwards with respect to the axis of rotation (28) and is arranged in the transition region between an air outlet nozzle (102) and a rounded portion (96) of the outflow housing (92). Device according to one of the preceding claims, characterized in that the outflow housing (210) is mounted on a base plate (218) of the axial fan (208) so as to be rotatable about the axis of rotation (28). Device according to one of the preceding claims, characterized in that the device (160) has a plurality of heat exchangers (162, 164), each of which has an axial fan (166, 168) and. an exhaust housing (170, 172) is assigned, wherein the air flows conveyed by the axial fans (166, 168) can be fed to a common air outlet duct (168) via the air outlet openings (174, 176) of the exhaust housings (170, 172), and the air outlet openings (174, 176) are aligned obliquely to one another. Use of the device according to one of the preceding claims in a heat pump or air conditioning system or for cooling electronic components.

Images