DEVICE FOR EXCHANGING THERMAL ENERGY WITH THE AMBIENT AIR AND HEAT PUMP WITH SUCH A DEVICE

Description

[0001] The invention relates to a device for exchanging thermal energy with the ambient air, comprising a heat exchanger through which an airflow passes, at least one fan arranged downstream of the heat exchanger, which has an impeller rotatable about an axis of rotation with a blading for conveying the airflow through the heat exchanger, as well as an air supply device with at least one air inlet opening for supplying the airflow from the environment to the heat exchanger and an air discharge device with at least one air outlet opening for discharging the airflow from the at least one fan to the environment, wherein the at least one air inlet opening and the at least one air outlet opening are arranged on the same side of the device.

[0002] Furthermore, the invention relates to a heat pump with such a device.

[0003] Devices of the type mentioned above are used, for example, in air conditioning systems and heat pumps, where the heat exchanger can function as an evaporator to absorb heat energy from the ambient air or as a condenser to release heat energy to the ambient air. Heat pumps are often positioned outside buildings or in basements. However, installation outside buildings requires considerable space, and installation in basements necessitates long supply and exhaust air ducts, which result in airflow losses that impair the energy efficiency of the heat pumps. To counteract these disadvantages, heat pumps are frequently installed underground outside buildings or mounted on an exterior wall inside buildings.However, this requires a compact design of the heat pumps and necessitates the positioning of the at least one air inlet opening and the at least one air outlet opening on the same side of the heat pump, whereby there is a risk of backflow of the airflow from the at least one air outlet opening to the at least one air inlet opening, so that a thermal short circuit is formed and consequently the energy efficiency is also impaired.

[0004] From JP S57 70029 U, a device for exchanging heat energy with the ambient air is known, having the features of the preamble of claim 1.

[0005] From KR 100 540 272 B1 a device for exchanging heat energy with the ambient air is known, in which an axial fan is used which is located directly in front of an air outlet opening.

[0006] The object of the present invention is to further develop a device and a heat pump of the type mentioned above in such a way that they have improved energy efficiency.

[0007] This problem is solved by a device having the features of claim 1.

[0008] In the device according to the invention, the airflow is supplied to the heat exchanger via at least one supply air duct that opens into the heat exchanger. The airflow extends along an inlet surface of the heat exchanger that is exposed to the airflow and tapers continuously along this inlet surface. As the airflow successively enters the heat exchanger, the volume flow rate within the supply air duct decreases in the direction of flow along the inlet surface. To compensate for this steadily decreasing volume flow rate, the at least one supply air duct tapers continuously along the inlet surface in the direction of flow. This results in the airflow being guided across the entire inlet surface at a practically constant flow velocity, avoiding dead spots, thus minimizing flow losses that impair energy efficiency.

[0009] The airflow is discharged to the environment via at least one air outlet, located on the same side of the device as the at least one air inlet. To prevent backflow of the airflow from the at least one air outlet to the at least one air inlet, the flow cross-section of the at least one air outlet, which defines the airflow velocity, is smaller than the flow cross-section of the at least one air inlet, which defines the airflow velocity. The smaller flow cross-section results in an outlet velocity that is greater than the inlet velocity. This prevents backflow of the airflow and thus a thermal short circuit that would impair energy efficiency.The device according to the invention is therefore characterized by high energy efficiency, whereby flow losses can be kept low and practically no mixing of the outgoing airflow with the incoming airflow takes place.

[0010] According to the invention, at least one fan is designed as an axial fan, to which an exhaust housing is assigned. This housing receives the airflow conveyed by the axial fan on the outflow side and has a housing outlet opening through which the airflow can flow tangentially with respect to a swirl motion imposed on the airflow by the rotating blades of the axial fan impeller. Axial fans enable a particularly uniform 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 order to position the at least one air outlet opening on the same side of the device as the at least one air inlet opening, it is advantageous to deflect the airflow upstream and downstream of the axial fan by 90° each time. To minimize the pressure losses caused by the deflection, the device according to the invention utilizes the swirl of the airflow generated by the rotating blades of the axial fan impeller for low-loss deflection. For this purpose, the airflow conveyed by the axial fan is received on the downstream side by an exhaust housing, the outlet opening of which is positioned such that the airflow can pass through it in a tangential direction relative to the swirl motion.Due to the swirl imparted by the axial fan, the airflow within the exhaust housing undergoes a movement around the fan's axis of rotation and is directed tangentially towards the housing outlet opening. This results in a parallel flow at the outlet opening, which uniformly fills the entire cross-section of the opening, with the airflow exhibiting virtually no residual swirl. Consequently, the deflection of the airflow downstream of the axial fan occurs with minimal flow losses.

[0011] The exhaust housing, axially offset from the impeller and the motor of the axial fan (which drives the impeller around its axis of rotation), forms an air intake chamber. This chamber captures the conveyed airflow across the entire cross-section of the impeller and motor and is penetrated by the axis of rotation. In a rear view, the exhaust housing covers the impeller and motor like a hood. The airflow conveyed by the axial fan can thus be captured by the exhaust housing over a large area and consequently with minimal loss across the entire cross-section of the impeller and motor.

[0012] The housing outlet opening is located in a rear view of the outflow housing above one half of the blading, with the blading on this half rotating towards the housing outlet opening.

[0013] It is advantageous if the flow outlet cross-section of the at least one air outlet, which defines the exit velocity of the airflow, is at most 0.8 times, and in particular at most 0.7 times, the flow inlet cross-section of the at least one air inlet, which defines the inlet velocity of the airflow. The smaller the flow outlet cross-section defining the exit velocity, the greater the exit velocity of the airflow. The airflow is thus virtually flung out of the device, so that practically no mixing with the incoming airflow occurs.

[0014] In an advantageous embodiment of the invention, the heat exchanger is designed in a plate-like shape. The inlet surface of the heat exchanger can, for example, be rectangular.

[0015] Alternatively, the heat exchanger can be designed in an L-shape, comprising a first leg and a second leg. The two legs are aligned at an angle to each other, for example, at approximately 90°. The inlet surface of the heat exchanger extends over both legs, and the L-shape results in a very compact design.

[0016] The supply air duct can extend across both legs of the heat exchanger. The airflow can thus be supplied to the inlet surfaces of both legs via the supply air duct, which continuously tapers along the inlet surfaces of both legs to ensure that the airflow is supplied at a virtually constant velocity.

[0017] Alternatively, the device can be provided with two supply air ducts, each extending over one of the two legs. These supply air ducts, each extending along one of the inlet surfaces of the legs, taper continuously along the inlet surfaces, thus directing the airflow to the heat exchanger at a virtually constant velocity across the inlet surface.

[0018] In an L-shaped heat exchanger design, it is advantageous if the fan's axis of rotation is inclined towards the surface normal of one of the two legs of the heat exchanger, in the direction of the other leg. This promotes uniform and low-loss flow through the heat exchanger via both legs. In particular, the axis of rotation can be aligned towards the transition zone between the two legs.

[0019] In a preferred embodiment of the invention, the two legs of the heat exchanger are of different lengths, and the axis of rotation is inclined relative to the surface normal of the longer leg in the direction of the shorter leg. Such an inclination of the axis of rotation results in a particularly low-loss flow through the heat exchanger.

[0020] It is advantageous if the axis of rotation of at least one fan is inclined relative to a surface normal of the heat exchanger in the direction of an end section of a supply air duct. Such an inclination of the axis of rotation promotes a uniform and low-loss flow through the heat exchanger.

[0021] In an advantageous embodiment of the invention, the at least one supply air duct tapers wedge-shaped along the inlet surface of the heat exchanger. For example, it can be provided that the at least one supply air duct has wall sections inclined obliquely to the vertical in a horizontal operating position of the device.

[0022] Preferably, the outlet opening of the exhaust housing is arranged downstream of the axial fan in a region of the exhaust housing laterally offset from the axial fan's central plane, wherein the central plane is aligned coaxially with the axial fan's axis of rotation, and wherein the impeller blades rotate in this laterally offset region relative to the outlet opening in a rear view of the exhaust housing. In a rear view of the exhaust housing along the axis of rotation, the axial fan's central plane, aligned coaxially with the axis of rotation, divides the impeller into two halves. The outlet opening is arranged downstream of the axial fan on the side of the central plane on which the impeller blades rotate relative to the outlet opening when rotating about the axis of rotation in the rear view of the exhaust housing.As a result, the air flowing on this side of the center plane moves essentially tangentially to the housing outlet opening, while the air flowing on the opposite side of the center plane moves in a loop-like motion towards the housing outlet opening. This creates a parallel flow within the housing outlet opening, which practically fills the entire cross-section of the housing outlet opening uniformly and exhibits virtually no swirl.

[0023] When using a large-area heat exchanger, it is advantageous if the device has several fans arranged next to each other.

[0024] In particular, the device may be provided to have two axial fans, each of which is associated with an exhaust housing that receives the airflow conveyed by the respective axial fan, with the housing outlet openings of the exhaust housings opening into a common air outlet channel of the air discharge device.

[0025] It is advantageous if the two axial fans and their respective associated exhaust housings are identical in design, with the exhaust housings having different rotational positions relative to the respective fan axis of rotation, so that their housing outlet openings are inclined towards each other in order to feed the respective conveyed airflows into the common air outlet duct with minimal loss.

[0026] It may be provided that an air inlet duct is arranged upstream of the at least one supply air duct. The air inlet duct may have several duct sections that are flow-tightly connected to prevent leakage. The air inlet duct may, for example, have an air inlet nozzle and / or a bend.

[0027] In an advantageous embodiment of the invention, an air outlet duct is arranged downstream of the at least one fan. The air outlet duct can have several duct sections which are flow-tightly connected to prevent leakage. The air outlet duct can, for example, comprise a pipe bend and / or an air outlet nozzle.

[0028] It is advantageous if at least one end section of the air outlet duct tapers continuously in the direction of flow, in order to increase the flow velocity of the airflow.

[0029] To reduce the noise emission of the device, the air discharge system in a preferred embodiment of the invention includes a silencer. The silencer may define the flow outlet cross-section.

[0030] The silencer is preferably designed as a baffle silencer comprising a housing in which several spaced-apart baffles are arranged between two opposing side walls of the housing. The flow cross-sections between the baffles and between the baffles and the side walls collectively form the outlet cross-section that defines the exit velocity of the airflow. In such a design, the airflow is guided between the baffles to reduce noise emissions. The outlet cross-section, which defines the exit velocity of the airflow, is formed by the sum of the flow cross-sections arranged between adjacent baffles and between the baffles and the side walls.

[0031] To widen the airflow, in a preferred embodiment of the invention, the air discharge device has a first diffuser with an opening angle of a maximum of 8°, wherein the outlet cross-section of the diffuser forms the flow outlet cross-section that defines the exit velocity of the airflow. To prevent the airflow from separating from the wall of the first diffuser, the opening angle of the first diffuser is a maximum of 8°.

[0032] In an advantageous embodiment of the invention, a second diffuser is arranged downstream of the first diffuser, which is configured to form a free jet. In particular, the opening angle of the second diffuser can be at least 90°, for example 140°. The second diffuser can be directly connected to the first diffuser. In such an embodiment, an edge forms between the two diffusers at which the airflow separates to form a free jet. The outlet cross-section of the first diffuser forms the flow outlet cross-section, which defines the exit velocity of the airflow, whereas the second diffuser, and in particular its outlet cross-section, has no noticeable influence on the exit velocity of the airflow due to the formation of the free jet at the edge between the two diffusers.

[0033] As already mentioned at the outset, the invention also relates to a heat pump. In order to design the heat pump in such a way that it has improved energy efficiency, the heat pump comprises a device of the type described above.

[0034] The heat pump can, for example, be designed as an underground heat pump, which is embedded in a base plate or sunk into the ground.

[0035] It can also be provided that the heat pump can be positioned on an exterior wall of a building room, with at least one air inlet opening and at least one air outlet opening being located on the exterior wall.

[0036] The following description of advantageous embodiments of the invention, in conjunction with the drawing, serves for further explanation. The drawing shows: Figure 1: an exploded view of a first advantageous embodiment of a heat pump according to the invention with a first advantageous embodiment of a device according to the invention for exchanging heat energy with the ambient air; Figure 2: a perspective view of the heat pump made of Figure 1 Figure 3: a perspective view of a second advantageous embodiment of a heat pump with a second advantageous embodiment of a device for exchanging heat energy with the ambient air; Figure 4: a third advantageous embodiment of a heat pump with a third advantageous embodiment of a device for exchanging heat energy with the ambient air; Figure 5: a perspective view of a silencer of the device made of Figure 4Figure 6: a perspective view of an air outlet duct forming a first diffuser and a second diffuser immediately adjoining the first diffuser; Figure 7: a perspective view of a fourth embodiment of a heat pump with a fourth embodiment of a device for exchanging heat energy with the ambient air;

[0037] In the Figure 1 and 2 Figure 10 schematically illustrates a first advantageous embodiment of a heat pump 10 according to the invention, which comprises a first advantageous embodiment of a device according to the invention for exchanging heat energy with the ambient air. The device is designated overall by reference numeral 12.

[0038] The device 12 has a planar, L-shaped heat exchanger 14 with a flat first leg 16 and a flat second leg 18 adjoining the first leg 16.

[0039] To convey an airflow through the heat exchanger 14, the device 12 has a fan 20 arranged downstream of the heat exchanger 14 at a distance from it, which in the illustrated embodiment is designed as an axial fan 22. Upstream of the heat exchanger 14, the device 12 has an air supply device 24 for supplying the airflow from the environment to the heat exchanger 14, and downstream of the axial fan 22, the device 12 has an air discharge device 26 for releasing the airflow to the environment.

[0040] The air supply device 24 has an air inlet duct 28 that forms an air inlet nozzle 30. A supply air duct 32 is directly connected to this nozzle in the direction of airflow. This supply air duct tapers in a wedge shape in the direction of airflow and extends along an inlet surface 34 of the heat exchanger 14, which is exposed to the airflow. The inlet surface 34 extends over the first leg 16 and the second leg 18, so that the airflow can be supplied to both legs via the air inlet nozzle 30 and the supply air duct 32. The air inlet nozzle 30 has a circumferential inlet rim 36 facing away from the supply air duct 32, which surrounds an air inlet opening 38 of the air supply device 24 in a circumferential direction.

[0041] The axial fan 22 is mounted on a bulkhead 39, which has an opening 40. The axial fan 22 has a motor 41 that rotates an impeller 42 about an axis of rotation 44. The impeller 42 has blades 46. Under the action of the rotating blades 46, the airflow downstream of the axial fan 22 is given a swirling motion about the axis of rotation 44. The bulkhead 39 separates the inlet side of the axial fan 22 from its outlet side to prevent internal backflow.

[0042] The axis of rotation 44 is inclined to a surface normal 48 of the first leg 16 in the direction of the second leg 18 and in the direction of an end region 50 of the supply air duct 32 facing away from the air inlet nozzle 30. This supports the uniform flow through the heat exchanger 14 across its entire inlet surface 34.

[0043] The air discharge device 26 has an exhaust housing 52 downstream of the axial fan 22. This housing is designed like a hood and forms an air intake chamber 45, axially offset from the impeller 42 and the motor 41. The axis of rotation 44 penetrates this air intake chamber. In a rear view along the axis of rotation 44, the exhaust housing 52 covers the impeller 42 and the motor 41, whose motor axis (not shown in the drawing) is aligned coaxially with the axis of rotation 44. The exhaust housing 52 receives the airflow delivered by the axial fan 22 over a large area across the entire cross-section of the impeller 42 and the motor 41. The exhaust housing 52 has a housing outlet opening 54, to which an air outlet channel 56 in the form of an air outlet nozzle 58 is connected in the direction of airflow.The air outlet nozzle 58 has an air outlet rim 60 facing away from the housing outlet opening 54, which circumferentially surrounds an air outlet opening 62. The airflow can be released to the environment via the air outlet opening 62.

[0044] The housing outlet opening 54 is arranged in a rear view of the exhaust housing 52 above one half of the blading 46, with the blading 46 rotating towards the housing outlet opening 54 on this half, so that the airflow can be directed tangentially to the housing outlet opening 54 by utilizing the swirl motion of the airflow caused by the rotating blading 46. This is shown below with reference to the Figure 4 The third advantageous embodiment, shown schematically, will be explained in more detail below.

[0045] The heat pump 10 can be buried in the ground and for this purpose has a trough-shaped housing 64, which is closed by a cover 66 that can be placed on the housing 64. The cover 66 sits airtight on the top of the heat exchanger 14 and the bulkhead 39 with sealing elements 67 in between.

[0046] The housing 64 has a central housing section 68 that accommodates the heat exchanger 14, the bulkhead 39, and the axial fan 22. The central housing section 68 also accommodates a hydraulic housing 72, which is arranged laterally next to the first leg 16 of the heat exchanger 14, as well as laterally next to the bulkhead 39 and the axial fan 22, and which houses the hydraulic components of the heat pump 10, in particular a compressor, a condenser, and an expansion valve. The hydraulic components are known per se to those skilled in the art and are not shown in the drawing for the sake of clarity.

[0047] Upstream of the middle housing section 68, the trough-shaped housing 64 has a front housing section 74 that forms the intake air duct 32, and downstream of the middle housing section 68, the trough-shaped housing 64 has a rear housing section 76 that forms the exhaust housing 52.

[0048] The cover 66 has a cover plate 78 covering the middle housing section 68 and forms the air inlet nozzle 30 and the air outlet nozzle 58, which are integrally connected to the cover plate 78.

[0049] The supply air duct 32 extends along the inlet surface 34 and opens into the heat exchanger. The flow cross-section of the supply air duct 32 decreases continuously along the inlet surface, thus compensating for the steadily decreasing volume flow rate caused by the successive entry of air into the heat exchanger. As a result, the airflow is supplied to the heat exchanger 14 at a virtually constant velocity across the entire inlet surface 34, avoiding dead zones. This virtually constant velocity across the entire inlet surface 34 reduces any potential flow losses of the airflow. The flow conditions within the supply air duct 32 are described in Figure 2 schematically represented using exemplary streamlines a, b, c, d, e and f.

[0050] The inlet velocity of the airflow into the air supply device 24 is defined by the flow inlet cross-section of the inlet surface 80 of the air inlet opening 38, which is circumferentially surrounded by the inlet edge 36 of the air inlet nozzle 30. The outlet velocity of the airflow from the air discharge device 26 is defined by the flow outlet cross-section of the outlet surface 82 of the air outlet opening 62, which is circumferentially surrounded by the air outlet edge 60 of the air outlet nozzle 58. The flow outlet cross-section is significantly smaller than the flow inlet cross-section. In the illustrated embodiment, the flow outlet cross-section is approximately half the size of the flow inlet cross-section. This results in the outlet velocity of the airflow being significantly greater than the inlet velocity of the airflow.The higher exit velocity ensures that the outgoing airflow does not mix with the incoming airflow and thus avoids a thermal short circuit, even though the air outlet opening 62 is located on the same side of the device 10, namely its top side, as the air inlet opening 38.

[0051] The heat pump 10 and the device 12 are thus characterized by high energy efficiency, whereby flow losses of the airflow can be kept low despite the deflection of the airflow by a total of 180°.

[0052] In Figure 3 A second advantageous embodiment of a heat pump 100 according to the invention is shown schematically, which has a second advantageous embodiment of a device according to the invention for exchanging heat energy with the ambient air, which is designated by reference numeral 102. Figure 3Figure 1 shows an installation situation in which the heat pump 100 is submerged in an earth volume 104. The heat pump 100 and the device 102 are designed largely identically to those described above with reference to the Figure 1 and 2 The illustrated heat pump 10 and the device 12. For identical components, therefore, in Figure 3 the same reference symbols are used as in the Figure 1 and 2 , and with regard to these components, reference is made to the preceding explanations to avoid repetition.

[0053] The heat pump 100 and the device 102 differ from the heat pump 10 and the device 12 only in that the air inlet nozzle 30 and the air outlet nozzle 58 are omitted, so that the airflow from the environment can enter the supply air duct 32 directly and exit directly into the environment via the housing outlet opening 54 of the exhaust housing 52. The air supply device 24 is therefore formed by the supply air duct 32 and the air discharge device 26 is formed by the exhaust housing 52. The inlet cross-section of the supply air duct 32 forms the flow inlet cross-section, which defines the inlet velocity of the airflow, and the outlet cross-section of the housing outlet opening 54 forms the flow outlet cross-section, which defines the exit velocity of the airflow. The incoming airflow is in Figure 3The incoming airflow is illustrated by arrow 106, and the outgoing airflow is illustrated by arrow 108, with the respective lengths of arrows 106 and 108 representing the mean flow velocity of the incoming airflow 106 and the outgoing airflow 108, respectively. It is evident that the outgoing velocity is significantly greater than the incoming velocity, so that despite the arrangement of the air inlet and outlet openings on the top of the heat pump 100 and the device 102, a mixing of the two airflows and thus a thermal short circuit is avoided.

[0054] In Figure 4 A third advantageous embodiment of a heat pump 120 according to the invention is shown schematically, which has a third advantageous embodiment of a device according to the invention for exchanging heat energy with the ambient air, wherein the device as a whole is designated by reference numeral 122.

[0055] Also in Figure 4 The same reference symbols are used for identical components as in the Figure 1 and 2 used, and with regard to these components, reference is made to the preceding explanations to avoid repetition.

[0056] Figure 4Figure 1 shows an installation situation for the heat pump 120, in which the heat pump 120 is sunk into the ground to the side of a wall corner 121 of a building (shown with a dashed line). The device 122 has an air supply unit 124 with a first supply air duct 126 and a second supply air duct 128. The first supply air duct 126 extends along the inlet surface 130 of the first leg 16 of the heat exchanger 14, and the second supply air duct 128 extends along the inlet surface 132 of the second leg 18 of the heat exchanger 14. The two supply air ducts 126 and 128 taper in a wedge shape along their respective inlet surfaces 130 and 132, thereby ensuring a practically constant velocity across the inlet surfaces 130 and 132 while avoiding dead spots.

[0057] A first air inlet duct 134, in the form of a first air inlet nozzle 136, is directly upstream of the first supply air duct 126, and a second air inlet duct 138, in the form of a second air inlet nozzle 140, is directly upstream of the second supply air duct 128. Both air inlet nozzles 136 and 140 have a rounded edge 142 at their inlet edge facing away from the respective supply air duct 126 and 128, respectively, which ensures a smooth airflow. The air inlet nozzles 136 and 140, in combination with the supply air ducts 126 and 128, form the air supply device 124. The inlet edges of the air inlet nozzles 136 and 140 each form an air inlet opening. The flow inlet cross-sections of the air inlet openings define the inlet velocity of the airflow.

[0058] At the in Figure 4In the illustrated embodiment, a bend 144 with a guide plate 146 is connected to the air outlet nozzle 58, with the help of which the exiting airflow is directed in the direction away from the wall corner 121.

[0059] A silencer 148 is inserted into the air outlet nozzle 58 of the device 122, which is in Figure 5The silencer 148 is designed as a baffle silencer 150, which has a housing 152. The housing 152 has two opposing side walls 154, 156, which are connected to each other via an end wall 158 and a rear wall 160. Between the two side walls 154, 156, several baffles 162 of the baffle silencer 150 extend from the end wall 158 to the rear wall 160. The baffles 162 are spaced apart from each other and from the side walls 154, 156 and form outflow cross-sections 164 between themselves and the side walls 154, 156, through which the airflow can pass. The sum of the outflow cross-sections 164 forms the flow outlet cross-section, which defines the exit velocity of the airflow. The exiting airflow is in Figure 5 illustrated by the arrows 166.

[0060] In Figure 4Two streamlines a, b of the airflow entering the first supply air duct 126 and the second supply air duct 128 from the surroundings via the first air inlet nozzle 136 and the second air inlet nozzle 140, respectively, are shown schematically as examples. Furthermore, in Figure 4An example of a streamline c of the exiting airflow is shown schematically. Streamline c shows the tangential deflection of the airflow within the exhaust housing 52, utilizing the swirl motion about the axis of rotation 44 generated by the axial fan 22. For this purpose, the housing outlet opening 54 of the exhaust housing 52 and the air outlet nozzle 58 adjoining the housing outlet opening 54 are arranged in a rear view, looking along the axis of rotation 44, above the half of the impeller 42 whose blades rotate towards the housing outlet opening 54. This ensures that the air flowing from this half of the impeller is conveyed to the housing outlet opening 54 with almost no deflection. The air flowing from the other half of the impeller 42, however, follows a loop-like motion. This results in a parallel flow in the area of ​​the housing outlet opening 54 and the air outlet nozzle 58, which has hardly any residual swirl.This allows for a low-loss redirection of the airflow downstream of the axial fan 22 by 90°.

[0061] In Figure 6A schematic representation shows an air outlet channel 170, formed by a first diffuser 172 and a second diffuser 174 immediately adjoining it in the flow direction. The opening angle of the first diffuser is a maximum of 8°. According to general knowledge in fluid mechanics, this represents the maximum opening angle for widening a subsonic flow without separation, thereby slowing it down and regaining static pressure. The second diffuser 174, which adjoins the first diffuser 172 via an edge 176, has an opening angle that results in the formation of a free jet of airflow. In the illustrated embodiment, the opening angle of the second diffuser 174 is at least 90°, for example, 140°. The free jet is illustrated by the wavy line 178, and the flow direction and velocity of the airflow are illustrated by the arrows 180.The flow outlet cross-section, which defines the exit velocity of the airflow, is determined by the exit cross-section of the first diffuser 172, whereas the design of the second diffuser 174 and in particular its exit cross-section has no influence on the exit velocity due to the formation of the free jet 178.

[0062] In Figure 7A fourth advantageous embodiment of a heat pump 200 according to the invention is schematically illustrated, which comprises a fourth advantageous embodiment of a device according to the invention for exchanging heat energy with the ambient air, wherein the device is designated by reference numeral 202. The heat pump 200 is embedded in a base plate 204 as an underfloor heat pump and has a very wide heat exchanger 206 for high heat energy transfer, to which an airflow from the environment can be supplied via a wedge-shaped supply air duct 208. This airflow is generated by two adjacent, identically designed axial fans, each of which is followed by an exhaust housing 210 or 212, respectively.The exhaust housings 210, 212 are identical in design to the exhaust housing 52 described above; however, they have different rotational positions relative to their respective axes of rotation, so that their respective housing outlet openings 214, 216 face each other and open into a common air outlet channel 218, through which the airflow is released to the environment. The direction and speed of the incoming airflow are shown in . Figure 7 The direction and speed of the outgoing airflow are illustrated by arrow 220, and the direction and speed of the outgoing airflow are illustrated by arrow 222. The two airflows 220 and 222 are antiparallel to each other, with the significantly higher speed of the outgoing airflow 222 ensuring that it does not mix with the incoming airflow 220 and form a thermal short circuit.

Claims

1. A device for exchanging thermal energy with the environmental air, comprising a heat exchanger (14; 206) through which an air flow can flow, at least one fan (20) arranged downstream of the heat exchanger, which has an impeller (42) with a blading (46) rotatable about an axis of rotation (44) for conveying the air flow through the heat exchanger (14; 206), as well as an air supply apparatus (24; 124) with at least one air inlet opening (38) for supplying the air flow from the environment to the heat exchanger (14; 206) and an air discharge apparatus (26) with at least one air outlet opening (62) for discharging the air flow from the at least one fan (20) to the environment, wherein the at least one air inlet opening (38) and the at least one air outlet opening (62) are arranged on the same side of the device (12; 102; 122; 202), and wherein the air supply apparatus (24; 124) has at least one inlet air channel (32; 126, 128; 208) opening into the heat exchanger (14; 206) which runs along an inlet surface (34; 130, 132) of the heat exchanger (14; 206) and continuously tapers along the inlet surface (34; 130, 132), and wherein the flow outlet cross-section of the at least one air outlet opening (62) defining the outlet rate of the air flow is smaller than the flow inlet cross-section of the at least one air inlet opening (38) defining the inlet rate of the air flow, characterised in that at least one fan (20) is designed as an axial fan (22) to which an outflow housing (52) is assigned which accepts the air flow conveyed by the axial fan (22) on the outflow side and which has a housing outlet opening (54) through which the air flow can flow in the tangential direction with regard to a swirl motion imparted to the air flow under the action of the rotating blading (46) of the impeller (42) of the axial fan (22), and in that the outflow housing (52), axially offset from the impeller (42) and from a motor (41) of the axial fan (22) rotatably driving the impeller (42) about the axis of rotation (44), forms an air acceptance space (45) which accepts the conveyed air flow over the complete cross-section of the impeller (42) and the motor (41) and is penetrated by the axis of rotation (44), wherein the outflow housing (52), in a rear view, covers the impeller (42) and the motor (41) in a hoodlike manner and the housing outlet opening (54), in a rear view of the outflow housing (52), is arranged over half of the blading (46), wherein the blading (46) rotates towards the housing outlet opening (54) on this half.

2. The device according to claim 1, characterised in that the flow outlet cross-section of the at least one air outlet opening (62) defining the outlet rate of the air flow is at most 0.8 times the flow inlet cross-section of the at least one air inlet opening (38) defining the inlet rate of the air flow.

3. The device according to claim 1 or 2, characterised in that the heat exchanger (206) is designed to be plate-shaped.

4. The device according to claim 1 or 2, characterised in that the heat exchanger (14) is designed to be L-shaped and has a first leg (16) and a second leg (18).

5. The device according to claim 4, characterised in that the inlet air channel (32) runs over both legs (16, 18) of the heat exchanger (14).

6. The device according to claim 4, characterised in that the device (122) has two inlet air channels (126, 128) which each run over one of the two legs (16, 18).

7. The device according to claim 4, 5 or 6, characterised in that the axis of rotation (44) of the fan (20) is inclined towards the surface normal (48) of one of the two legs (16, 18) in the direction of the other leg (16, 18).

8. The device according to claim 7, characterised in that the two legs (16, 18) of the heat exchanger (14) are of different lengths and the axis of rotation (44) is inclined towards the surface normal (48) of the longer leg (16) in the direction of the shorter leg (18).

9. The device according to any one of the preceding claims, characterised in that the axis of rotation (44) of the at least one fan (20) is inclined towards a surface normal of the heat exchanger (14) in the direction of an end region of an inlet air channel (32; 126, 128).

10. The device according to any one of the preceding claims, characterised in that the at least one inlet air channel (32; 126, 128; 208) tapers in a wedge-shaped manner along the inlet surface (34; 130, 132) of the heat exchanger (14; 206; 254).

11. The device according to any one of the preceding claims, characterised in that the device (122) has two axial fans, each of which is assigned an outflow housing (210, 212) which accepts the air flow conveyed by the respective axial fan, wherein the housing outlet openings (214, 216) of the outflow housings (210, 212) open into a common air outlet channel (218) of the air discharge apparatus (26).

12. The device according to any one of the preceding claims, characterised in that an air inlet channel (28; 134, 138) is arranged upstream of the at least one inlet air channel (32; 126, 128) and an air outlet channel (56; 170; 218) is arranged downstream of the at least one fan (20).

13. The device according to claim 12, characterised in that the air discharge apparatus (26) has a silencer (148), wherein the silencer (148) is designed as a background silencer (150) which has a housing (152), wherein several spaced apart backgrounds (162) are arranged between two opposite side walls (154, 156) of the housing (152) at a distance to the side walls (154, 156), wherein the outflow crosssections between the backgrounds (162) and between the backgrounds (162) and the side walls (154, 156) in their entirety form the flow outlet cross-section defining the outlet rate of the air flow.

14. The device according to any one of the preceding claims, characterised in that the air discharge apparatus (26) has a first diffusor (172) for widening the air flow with an opening angle of at most 8°, wherein the outlet cross-section of the first diffusor (172) forms the flow outlet cross-section defining the outlet rate of the air flow.

15. The device according to claim 14, characterised in that a second diffusor (174), which is adapted for forming a free jet, is arranged downstream of the first diffusor (172).