Diffuser for a heat pump and heat pump

Abstract

The diffuser (2) in an air / water heat pump (30) serves to deflect an axial airflow from an axial fan (32). It has a housing (4) with an annular inlet opening (16) for air and two laterally arranged radial outlet openings (14). For deflecting the airflow, the housing (4) has a flow guide device (18) which has a central guide cone (20) with a lateral surface (26), wherein the guide cone (20) widens along the central axis (22) in the axial direction (6) and extends to a cone base (25) which merges into the outer wall (10), and wherein guide vanes (28) are formed on the lateral surface (26) which extend from the inlet opening (16) in the axial direction (6) to the cone base (25), so that several separate deflection channels (29) are formed.

Description

[0001] The invention relates to a diffuser for a heat pump having the features of the preamble of claim 1 and to a heat pump having such a diffuser.

[0002] Such a diffuser can be found, for example, in DE 10 2019 203 171 A1 or in KR 2006 0034609 A.

[0003] In the heat pumps described therein, a diffuser is arranged downstream of an axial fan in the flow direction, which deflects the axial air flow generated by the axial fan to a radial flow outlet.

[0004] In DE 10 2019 203 171 A1, the diffuser is designed as a circular structural unit, the base of which is conical and the circumferential surface of which is formed by an access protection element which has a plurality of air openings for the outlet of the air flow.

[0005] In the KR 2006 0034609 A, a diffuser is also arranged downstream of an axial fan, which has a conical, pyramidal or roof-shaped flow guide element which deflects the air flow so that it can exit via radial outlet openings.

[0006] Such axial fans are used particularly in air / water heat pumps, where the axial fan draws an air flow through a heat exchanger acting as an evaporator and releases it into the environment.

[0007] If the air flow is diverted in an axial direction without deflection, the sound generated by the axial fan radiates directly into the environment.

[0008] Heat pumps with a radial air outlet therefore have a lower sound pressure level compared to units without a deflection and with an axial outlet. Since heat pumps, especially split units installed outdoors, are often located close to neighboring properties, heat pumps with a radial outlet and lower noise emissions are preferred for such designs.

[0009] However, the redirection of the initially axial air flow towards a radial air outlet leads to a pressure loss, which has a detrimental effect on the efficiency of the heat pump.

[0010] The well-known diffusers reduce the flow velocity, so that part of the kinetic energy of the air flow is recovered in the form of static pressure. This measure can reduce pressure loss.

[0011] Based on this, the present invention is based on the object of improving the flow guidance in a heat pump.

[0012] The object is achieved according to the invention by a diffuser having the features of claim 1 and by a heat pump with such a diffuser. The advantages and preferred embodiments cited with regard to the diffuser also apply analogously to the heat pump. The heat pump is, in particular, an air-to-water heat pump.

[0013] The diffuser initially comprises a housing which extends along a central axis in an axial direction and which has an inlet opening for air on an axial inlet side as well as a closed outer wall opposite this in the axial direction and further radial outlet openings arranged laterally.

[0014] The housing further comprises a flow guide device. This is either arranged inside the housing or the housing walls are shaped to form the flow guide device. The flow guide device is generally designed to deflect an axial air flow flowing in through the inlet opening during operation to the radial outlet openings. It comprises a central guide cone having a circumferential surface. The guide cone extends along the central axis in the axial direction to a conical base, which merges into the outer wall. Due to the conical design, this widens in the axial direction and, in particular, the cone diameter increases. The guide cone preferably has a circular base. Other bases are possible in principle.

[0015] A number of guide vanes are formed on the casing surface, which extend from the inlet opening in the axial direction to the cone root, so that a number of separate deflection ducts are formed. The air flow emitted by the axial fan is therefore divided into several partial flows, which are each deflected by the deflection ducts to a radial outlet opening. Each deflection duct is designed in particular as a closed duct. Each deflection duct connects the inlet opening to (exactly) one of the outlet openings. The guide vanes therefore each extend in the axial direction from a front outer wall formed on the inlet side along the casing surface to the rear outer wall. In the radial direction, they each extend from the casing surface to a side wall of the housing.Each closed deflection channel is therefore limited by the outer surface of the guide cone, the guide vanes and the housing walls.

[0016] When installed, the diffuser in the heat pump is directly connected to the axial fan. The axial fan typically has a fan hub with impellers attached to it.

[0017] The guide cone is preferably designed as a truncated cone, i.e., it has a flattened conical tip forming a truncated conical surface. This flattened conical tip is oriented coaxially with the fan hub. The truncated conical surface is preferably adapted to the fan hub in shape and size.

[0018] The inlet opening is particularly circular and, due to the guide cone with the truncated cone surface on the hub side, circular in shape. When installed, i.e., when the diffuser is installed in the heat pump, the inlet opening is located directly downstream of the axial fan. The diameter of the inlet opening is preferably adapted to the diameter of the axial fan, particularly in such a way that an annular outflow surface of the axial fan is aligned with the annular inlet opening. This achieves a particularly uniform flow pattern.

[0019] This design, with its guide cone and the guide vanes mounted on it, achieves a particularly uniform and defined deflection of the airflow delivered by the axial fan to the radial outlet openings. The targeted guidance of the airflow in the deflection channels and along the guide vanes reduces the risk of flow separation and turbulence in the flow, thereby reducing overall pressure losses during flow guidance.

[0020] The diffuser design also generally increases the flow cross-section, meaning the free flow area of ​​the inlet opening is smaller than the sum of the outlet areas of the outlet openings. This achieves the desired flow deceleration and creates a diffuser effect. This results in the recovery of the flow's kinetic energy in the form of static pressure.

[0021] Overall, this achieves the special advantage that the operating point of the axial fan is shifted in the characteristic curve field in such a way that a lower pressure build-up is required to convey the same air volume flow via the heat exchanger, which is connected upstream of the axial fan.

[0022] Overall, this results in improved efficiency for the axial fan and therefore for the entire heat pump. In particular, it is possible to reduce the fan frequency, i.e. the rotation speed of the axial fan, which has the particular advantage of reducing noise emissions. This also has a positive effect on the fan's electrical power consumption. Alternatively, with the same noise emissions and / or electrical power consumption, the air volume flow can be increased. This increases the evaporator capacity, reduces the electrical power consumption of a heat pump compressor and also - depending on the air temperature and humidity - reduces the formation of frost and ice on the heat pump's evaporator. The latter requires fewer defrosting processes during operation, which improves the heat pump's coefficient of performance.

[0023] According to a preferred embodiment, exactly two guide vanes are arranged, which are in particular offset by 180 degrees from each other. Therefore, exactly two deflection channels are created. Preferably, exactly one radial outlet opening is provided for each deflection chamber. This outlet opening can be equipped with an anti-interference device, for example, formed by a grid.

[0024] The guide vanes are preferably designed and arranged rotationally symmetrically with respect to the central axis. In particular, an n-fold rotational symmetry is formed, with the number of guide vanes being n. In the preferred variant with two guide vanes, n=2. Due to the rotational symmetry, the guide vanes lie identically one above the other after a rotation of 360 degrees / n. This means that after such a rotation, a subsequent guide vane assumes exactly the same position and contour as the leading guide vane.

[0025] To ensure particularly uniform flow, the outer surface is preferably concavely curved. This means that the outer surface—viewed in a sectional plane parallel to the axial direction (axial section) and along the center axis—is not straight but curved, specifically concavely curved, so that the outer surface transitions into the outer wall as smoothly as possible and preferably without any or almost no steps. The cone base can also be considered a section of the outer wall as a whole.

[0026] Each guide vane has a curved contour overall. It preferably has an inflow side that is curved, particularly concavely curved, at least in the area of ​​the cone root. This measure achieves particularly smooth flow guidance, and the air flow is deflected by the guide vanes as evenly and thus as turbulence-free as possible, especially in the area of ​​the cone root, and directed, for example, onto the outer surface of the cone root.

[0027] The transition of the guide vane in the axial direction into the cone root or into the rear outer wall is preferably at least largely free of steps and edges and / or preferably occurs at an obtuse angle of, for example, at least 110 degrees or even more.

[0028] During operation of an axial fan, an airflow is typically generated that has both an axial and a radial component. Therefore, the airflow does not exit the axial fan parallel to the axial direction, but rather at a defined outflow angle to the axial direction.

[0029] The upstream side of the guide vanes is generally a radially oriented surface facing the air flow coming from the axial fan and in particular its radial component.

[0030] Opposite the upstream side in the circumferential direction, each guide vane has a rear side, which is preferably generally shaped differently from the upstream side. The two sides are therefore asymmetrical to one another. The rear side is generally a side facing away from the air flow (its radial component). Specifically, for example, it is provided that a transition angle is formed in a transition region between the rear side and the cone root, which is smaller and thus more acute than the obtuse angle in the transition region between the upstream side and the cone root.

[0031] The respective guide vane is oriented with its upstream side in the area of ​​the inlet opening preferably at an angle of attack relative to a horizontal plane (plane perpendicular to the axial direction). This refers to an axial section oriented parallel to the axial direction and perpendicular to a radial direction. The angle of attack is measured as the angle that the upstream side forms with the horizontal plane on the rear side (i.e., facing the rear side).

[0032] The angle of attack is measured in the axial end region of the guide vanes, which is oriented toward the inlet opening. In this end region, the guide vane preferably has a straight section. Further along in the axial direction, the inflow side is curved, particularly concave, so that it merges into the cone root as described above.

[0033] In a preferred embodiment, the angle of attack changes in the radial direction. This means that the angle of attack has a different value in a radially inner region, on the hub side and thus oriented toward the center axis, than in a radially outer region, facing away from the fan hub and thus the center axis.

[0034] Specifically, the angle of attack decreases radially outward from the center axis. Preferably, the angle of attack decreases continuously.

[0035] In a preferred embodiment, the angle of attack corresponds to a defined, predetermined outflow angle α I of the axial fan upstream of the diffuser. As previously explained, the air flow emitted by the axial fan also has a radial component. This radial component therefore defines a flow angle relative to the axial direction. This flow angle is referred to as the outflow angle α I. By adapting the angle of attack to the outflow angle α I, the air flow is guided and deflected as evenly and as turbulence-free as possible.

[0036] As explained in more detail below, the outflow angle α I depends on the radial position and therefore varies in the radial direction. Accordingly, the angle of attack also varies in the radial direction, as previously described.

[0037] Alternatively, a constant angle is selected as the angle of attack depending on the outflow angle α I, whereby, for example, the average value of the outflow angle α I, which is variable in the radial direction, is used as the value for the angle of attack.

[0038] The discharge angle α I (variable in the radial direction) is a predetermined value that can be considered a device-specific value. It depends largely on the design of the axial fan and the nominal speed at which the axial fan operates during operation. If the axial fan can be operated at different speeds, a nominal speed for which the axial fan is designed is used to determine the discharge angle α I.

[0039] The discharge angle is preferably derived for a given operating point of the heat pump or from the discharge angles for several characteristic operating points, for example by averaging. The overall efficiency of the heat pump is often determined by the (weighted) efficiency of several characteristic operating points. The operating points A2 / W35 and A7 / W35 in particular have the greatest influence here. The number following the letter A stands for the air temperature in degrees Celsius at the air inlet and the number following the W stands for the heating water flow temperature in degrees Celsius. At these two points the fan is usually operated with an average volume flow. The discharge angle is therefore determined in particular on the basis of the flow conditions at selected operating points, specifically on the basis of the two operating points mentioned.The circumferential speed of the axial fan is used to determine the flow conditions. This not only keeps losses as low as possible across the entire operating range of the fan, but also optimizes the overall efficiency of the heat pump.

[0040] The determination of the radially variable outflow angle α I and thus the radially variable angle of attack is as follows:

[0041] The angle of attack αII of the guide vane is determined by the flow velocity vector c 2 at the trailing edge of an axial fan impeller. The angle of attack is described by the so-called flow triangle and depends on both the circumferential speed of the impeller u 2 in the respective radial section and the velocity vector v 2 of the outflow.

[0042] For the radially inner, hub-side area, due to the smaller hub-side radius r N that the peripheral speed u 2N of the axial fan is smaller. Conversely, the radial outside of the housing is larger due to the larger radius r G also the peripheral speed u 2G of the axial fan is larger. Accordingly, the angle of attack α II,G on the radially outer casing side is smaller than the angle α II,N on the radially inner side, facing the center axis, on the hub side.

[0043] To determine the outflow angle and thus also the angle of attack, the circumferential speed at at least one selected operating point is used. If multiple operating points are used, for example, an averaged circumferential speed of these operating points is used to determine the angle of attack, or the outflow angles are determined for each of these operating points and averaged.

[0044] Preferably, a weighted mean is determined when calculating each mean value, taking into account a weighting factor that, for example, relates to the efficiency of the heat pump at the respective operating point. The higher the efficiency, the higher the weighting factor.

[0045] Preferably, at least one of the sides selected from the inflow side and the opposite rear side of a respective guide vane, in particular the inflow side, transitions continuously and in particular seamlessly into a side wall of the housing at its radial end or (co-)forms the side wall. This homogeneous transition achieves a uniform flow deflection toward the radial outlet openings.

[0046] In a preferred embodiment, the housing is cuboid-shaped with at least two rectangular radial outlet openings. Preferably, exactly two such rectangular radial outlet openings are provided, which are formed on opposite side surfaces. Except for the inlet opening and the two outlet openings, the housing is completely closed.

[0047] An embodiment of the invention is explained in more detail below with reference to the figures, which show, in partially simplified representations: FIG 1 a perspective first view of a diffuser, FIG 2 a perspective second view of the diffuser according to FIG 1 , FIG 3 a highly simplified representation of an outdoor unit of a heat pump with diffuser, FIG 4A, 4B a front view and a side view of the diffuser with drawn section planes, namely axial section planes ( FIG 4A ) and horizontal cutting planes ( FIG 4B ) FIG 5A, 5B a sectional view along the axial section line A - A ( FIG 4A ) and a perspective view of the diffuser cut along this cutting line in a perspective view according to FIG 1 , FIG 6A, 6B a sectional view along the axial section line B - B ( FIG 4A ) and a perspective view of the diffuser cut along this cutting line in a perspective view according to FIG 1 , FIG 7A, 7B a sectional view along the axial section line C - C ( FIG 4A ) and a perspective view of the diffuser cut along this cutting line in a perspective view according to FIG 1 , FIG 8A, 8 legs, a sectional view along the horizontal section line D - D ( FIG 4B ) and a perspective view of the diffuser cut along this cutting line in a perspective view similar to FIG 1 , FIG 9A, 9 legs, a sectional view along the horizontal section line E - E ( FIG 4B ) and a perspective view of the diffuser cut along this cutting line in a perspective view similar to FIG 1 , and FIG 10A, 10B a sectional view along the horizontal section line F - F ( FIG 4B ) and a perspective view of the diffuser cut along this cutting line in a perspective view similar to FIG 1 .

[0048] One in FIG 1 as well as FIG 2 The diffuser 2 shown has a cuboid-shaped housing 4 which extends in an axial direction 6. The housing 4 has a front, axial inlet side 8, an outer wall 10 opposite this in the axial direction 4, two opposite, closed side walls 12 (top and bottom) and two further opposite open (lateral) side walls, on each of which a preferably rectangular outlet opening 14 is formed. These extend in particular over the entire surface of the respective side wall, thus are delimited only by the two adjacent side walls 12 and to the rear by the outer casing 10 and to the front by the wall of the inlet side 8.

[0049] The housing 4 has a depth in the axial direction 6 which is significantly (more than a factor of 2) smaller than a width and a height perpendicular to the axial direction 6. The inlet side 8 and the outer wall 10 have a square base in the exemplary embodiment.

[0050] A circular inlet opening 16 is formed on the inlet side 8. A flow guide device 18 is formed inside the housing 4. This device has a central guide cone 20 which widens in the axial direction. It has a circular conical base surface which is arranged concentrically to a central axis 22. The guide cone 20 is designed as a truncated cone which forms a (flat) truncated conical surface 24 at its front end oriented towards the inlet side 8. The guide cone 20 has a concavely curved outer surface 26. This extends from the truncated conical surface 24 to a conical base 25 which reaches to the outer wall 10 and merges into it. The conical base 25 and with it the outer surface 26 preferably merge seamlessly into the outer wall 10. The outer surface 26 is rotationally symmetrical.

[0051] In the exemplary embodiment, exactly two opposing guide vanes 28 are arranged on the lateral surface 26. In the exemplary embodiment, these vanes begin directly at the inlet opening 16 and therefore extend particularly into it, i.e., they extend into the wall region of the axial inlet side 8 surrounding the inlet opening 16. In the exemplary embodiment, they do not extend to a front end face of the axial inlet side 8, but are slightly spaced from it. However, this is not absolutely necessary.

[0052] In the exemplary embodiment, the guide vanes 28 begin slightly offset from the truncated cone surface 24 in the axial direction 6. However, they can also be aligned with this.

[0053] The guide vanes 28 extend over the entire depth of the housing 4 and reach to the inside of the outer wall 10. Because the two guide vanes 28 extend over the entire depth of the housing 4 in the axial direction 6, two separate deflection channels 29 are formed, via each of which a partial flow of the air flow is deflected and directed to one of the two outlet openings 14.

[0054] Such a diffuser 2 is used in a heat pump 30, as it is shown in a highly simplified and partially illustrated form in the FIG 3 is shown. In the FIG 3 In particular, an outdoor unit of a split heat pump 30 is shown, which is equipped with the diffuser 2. The heat pump 30, specifically the outdoor unit, typically has a heat exchanger (not shown here), which is usually designed as a finned heat exchanger. A refrigerant from a refrigeration circuit flows through this heat exchanger. With the help of an axial fan 32 (shown in dashed lines), air is drawn in and guided through the heat exchanger in the axial direction 6, and finally expelled again in the axial direction. In this process, heat is transferred from the air to the refrigerant.

[0055] The air flow discharged via the axial fan 32 in the axial direction 6 flows into the diffuser 2 via the annular inlet opening 16, is deflected there by means of the flow guide device 18 and leaves the diffuser 2 in the radial direction via the two outlet openings 14. The diffuser 2 is arranged directly in front of the axial fan 32 and is mounted, for example, on the outside of an outer wall of a housing of the heat pump 30.

[0056] The axial fan 32 has several, typically three, impeller blades 34 attached to a fan hub 36. The axial fan 32 defines a circular outflow area corresponding to the dashed circle minus the area for the fan hub 36.

[0057] The inlet opening 16 is designed correspondingly thereto, preferably has the identical annular surface and is in particular aligned with the outflow surface.

[0058] The special design of the flow guide device 18 is particularly evident from the various sectional views of the Figuren 4A, 4B until FIG 10A, 10B .

[0059] In the various perspective sectional views according to the "B-figures" ( FIG 5B, FIG 6B ... FIG 10B ) the traffic cone 20 with its circular base and its concave curved surface 26 can be clearly seen (see in particular FIG 6B ). In particular, it can be seen that the lateral surface 26 in the region of the conical base 25 merges smoothly and without edges into the inside of the outer wall 10.

[0060] Furthermore, the arrangement of the guide vanes 28 on the lateral surface 26 can be seen from these "B-figures." The guide vanes 28 generally have two opposite sides, which are referred to as the inflow side 38 and the rear side 40. The guide vanes 28 extend continuously in the axial direction 6 from a front region oriented toward the inlet side 8 to the outer wall 10 ( FIG 5B - FIG 7B ). At the same time, they extend in a radial direction from the guide cone 26 to the closed side wall 12 ( FIG 8B - FIG 10 B) . The two guide vanes 28 therefore form the two separate and closed deflection channels 29 ( FIG 6A, 6B ) trained.

[0061] The guide vanes 28 are preferably mounted vertically on the lateral surface 26. The two guide vanes 28 are arranged offset by 180 degrees relative to the central axis 22. In particular, they are designed to be rotationally symmetrical with respect to a 180-degree rotation around the central axis 22.

[0062] The guide vanes 28 are designed to be straight and radial at their front end, oriented toward the inlet side 8. They preferably widen both in the axial direction 6 toward the outer wall 10 and in the radial direction, thus toward the side walls 12.

[0063] In the horizontal sections according to FIG 9B und FIG 10B It is clearly visible that a respective guide vane 28 has an approximately T-shaped cross-sectional profile in such a horizontal section, with the two opposite sides (inflow side 38 and rear side 40) each being concavely curved. The design is preferably such that at least one of these sides, specifically the inflow side 38, and preferably both sides, merges continuously and seamlessly into the side walls 12, or co-forms them. This achieves a particularly uniform flow deflection.

[0064] In connection with the "A-figures", especially in connection with the FIG 5A and the FIG 7A In the following, a special element is explained with regard to the orientation of the respective guide vanes 28, specifically their inflow side 38: The inflow side 38 is oriented in its end region, which faces the inlet side 8, at an angle of attack αII with respect to a horizontal plane H (plane perpendicular to the axial direction 6). The angle of attack αII is defined by a straight line that is laid through the preferably rectilinear end region on the inflow side 38, and the horizontal plane H, namely the rear angle, i.e. the angle measured from the horizontal plane H in the direction of the rear side 40 to the previously defined straight line (compare Figur 5A ). This angle of attack αII is determined in particular by an outflow angle αI of the axial fan 32, as explained above. The angle of attack αII depends on the radial position and therefore changes in the radial direction. As can be seen in particular by comparing the FIG 5A with FIG 7A As can be seen, the angle of attack αII decreases continuously, starting from a radially inner, hub-side angle of attack αII N , to a radially outer, housing-side angle of attack αII G . The angle of attack αII varies depending on the radial position, for example between 95 degrees and 60 degrees and in particular between 90 degrees and 70 degrees.

[0065] Based on the vertical sections according to the "A-Figures" it can also be seen that a respective guide vane 28 is at least in the radially outer regions ( FIG 5A, FIG 6A ) merges into the outer wall 10 at an obtuse angle β at its rear end viewed in the axial direction 6. This is particularly pronounced in the radially outer regions, ie this obtuse angle β increases continuously in the axial direction 6.

[0066] Overall, the curvature and thus the concave curvature of the inflow side 38 is more pronounced radially outward, ie the concave curvature increases in the axial direction 6.

[0067] Overall, with the diffuser 2 described here, especially by means of the flow guide device 18, the most homogeneous deflection of the air flow from the inlet opening 16 to the radial outlet openings 14 is achieved, and the special design of the guide vanes 28, in particular in conjunction with the guide cone 20, achieves a particularly turbulence-free deflection. Bezugszeichenliste

[0068] 2Diffuser 4Housing 6Axial direction 8Inlet side 10Outer wall 12Closed side wall 14Outlet opening 16Inlet opening 18Flow guide device 20Guide cone 22Central axis 24Frustum surface 25Cone base 26Shell surface 28Guide vanes 29Deflection duct 30Heat pump 32Axial fan 34Impeller blades 36Fan hub 38Inlet side 40Rear side α I Fan discharge angle α I,G Fan discharge angle on the casing side (radially outer) α I,N Fan discharge angle on the hub side (radially inner) α II Guide vane angle α II,G Guide vane angle on the casing side (radially outer) α II,N Guide vane angle on the hub side (radially inner) βAngle

Claims

1. Diffuser (2) for a heat pump (30) with - a housing (4) which extends along a central axis (22) in an axial direction (6) and has, on an inlet side (8), a particularly circular or annular inlet opening (16) for air, a closed outer wall (10) opposite in the axial direction (6), and laterally arranged, radial outlet openings (14), wherein - the housing (4) further comprises a flow guide device (18) for deflecting an air flow flowing in via the inlet opening (16) during operation to the radial outlet openings (14), wherein - the flow guide device (18) has a central guide cone (20) with a lateral surface (26), wherein the guide cone (20) widens along the central axis (22) in the axial direction (6) and extends to a conical base (25) which extends into the outer wall (10) passes over, characterized by, - guide vanes (28) are formed on the lateral surface (26) and extend from the inlet opening (16) in the axial direction (6) to the cone root (25), so that a plurality of separate deflection channels (29) are formed.

2. Diffuser (2) according to the preceding claim, characterized in that two guide vanes (28) are arranged, which are in particular offset by 180 degrees from one another.

3. Diffuser (2) according to one of the preceding claims, characterized in that the guide vanes (28) are rotationally symmetrical with respect to the central axis (22).

4. Diffuser (2) according to one of the preceding claims, characterized in that the lateral surface (26) is concavely curved.

5. Diffuser (2) according to one of the preceding claims, characterized in that a respective guide vane (28) has an inflow side (38) which is curved, in particular concavely curved, at least in the region of the cone root (25).

6. Diffuser (2) according to the preceding claim, characterized in that the respective guide vane (28) has a rear side (40) opposite the inflow side (38) which is shaped differently than the inflow side (38).

7. Diffuser (2) according to one of the two preceding claims, characterized in that the inflow side (38) extends in the axial direction (6) from the inlet opening (16) to the outer wall (10) and - viewed in an axial section parallel to the axial direction (6) and perpendicular to a radial - is oriented in the region of the inlet opening (16) at an angle of attack (αII) with respect to a horizontal plane (H), wherein the angle of attack (αII) changes in the radial direction.

8. Diffuser (2) according to the preceding claim, characterized in that the angle of attack (αII) decreases in the direction starting from the central axis (22).

9. Diffuser (2) according to one of the two preceding claims, characterized in thatthe inflow side (38) extends in the axial direction (6) from the inlet opening (16) to the outer wall (10) and - viewed in an axial section parallel to the axial direction (6) and perpendicular to a radial - is oriented in the region of the inlet opening (16) at an angle of attack (αII) with respect to a horizontal plane (H), and the angle of attack (αII) corresponds to a defined outflow angle (αI) of an axial fan (32) connected upstream of the diffuser (2).

10. Diffuser (2) according to one of the preceding claims, characterized in that a respective guide vane (28) has an inflow side (38) and an opposite rear side (40) and that at least one of these sides, in particular the inflow side (38) at its radial end, merges continuously and in particular without a step into a side wall (12) of the housing (30) or forms this.

11. Diffuser (2) according to one of the preceding claims, characterized in thatthe housing (4) is cuboid-shaped with at least and preferably exactly two rectangular radial outlet openings (14).

12. Heat pump (30) with an axial fan and a diffuser (2) arranged downstream of the axial fan (6) according to one of the preceding claims.

Images