Indoor unit and heating and ventilation system

Abstract

The utility model discloses an indoor unit and a heating and ventilation system. The indoor unit comprises a shell and a wind wheel. The shell is provided with a heat exchange cavity, a wind wheel cavity and a diffusion cavity which are sequentially communicated and comprises a front volute tongue and a rear volute tongue, the front volute tongue is arranged at the joint of the wind wheel cavity and the heat exchange cavity, and the rear volute tongue is arranged at the joint of the diffusion cavity and the wind wheel cavity. The wind wheel is located between the front volute tongue and the rear volute tongue. In the datum plane, the rotation center of the wind wheel is a point O, the axis penetrating through the rotation center and extending in the height direction of the installation environment is S, the front volute tongue and the rear volute tongue are arranged on the two sides of the axis S respectively, the axis S and the top wall and the bottom wall of the wind wheel cavity intersect at a point J and a point P respectively, the end point, close to the axis S, of the front volute tongue is a point A, and the end point, close to the axis S, of the rear volute tongue is a point L; the angle AOJ meets the relation that the angle AOJ is larger than or equal to 25 degrees and smaller than or equal to 35 degrees, and the angle POL meets the relation that the angle POL is larger than or equal to 15 degrees and smaller than or equal to 30. According to the technical scheme, aerodynamic efficiency can be improved, the noise level is lowered, and user experience is improved.

Description

Technical Field

[0001] The present application relates to the field of HVAC technology, and in particular to an indoor unit and a HVAC system. Background Art

[0002] The HVAC system includes an air conditioner indoor unit that is used to regulate the indoor environment.

[0003] In the related art, in order to reduce space occupation and fit for room installation, some indoor units are constructed with a thinner body thickness. Due to the thin body thickness, the air inlet and outlet of some indoor units are roughly in the same plane, and the air flow turns greatly, resulting in low aerodynamic efficiency and high noise, which affects the user experience. Utility Model Content

[0004] The embodiments of the present application provide an indoor unit and a HVAC system, which can improve aerodynamic efficiency and reduce noise levels.

[0005] In a first aspect, an embodiment of the present application provides an indoor unit, comprising:

[0006] A housing, provided with a heat exchange chamber, a wind wheel chamber and a pressure diffuser chamber which are connected in sequence, and comprising a front volute tongue and a rear volute tongue, wherein the front volute tongue is arranged at the transition between the wind wheel chamber and the heat exchange chamber, the rear volute tongue is arranged at the transition between the pressure diffuser chamber and the wind wheel chamber, and the front volute tongue is located above the rear volute tongue; and

[0007] A wind wheel, located between the front volute tongue and the rear volute tongue;

[0008] A plane perpendicular to the axial direction of the wind wheel is set as a reference plane. Within the reference plane, the rotation center of the wind wheel is point O, and the axis passing through the rotation center and extending along the height direction of the installation environment is S. The front volute tongue and the rear volute tongue are respectively arranged on both sides of the axis S. The axis S intersects with the top wall and the bottom wall of the wind wheel cavity at points J and P respectively. The end point of the front volute tongue close to the axis S is point A, and the end point of the rear volute tongue close to the axis S is point L. ∠AOJ satisfies the relationship: 25°≤∠AOJ≤35°, and ∠POL satisfies the relationship: 15°≤∠POL≤30°.

[0009] In one embodiment, within the reference plane, the end point of the front volute tongue away from the axis S is point K, ∠KOL is the air inlet angle of the indoor unit, and the relationship is satisfied: 150°≤∠KOL≤170°.

[0010] Based on the above embodiments, both noise and air intake effects can be taken into consideration to ensure the user experience.

[0011] In one embodiment, the end point of the rear volute tongue away from the axis S is point N;

[0012] ∠AOK is the envelope angle of the front volute tongue, ∠NOL is the envelope angle of the rear volute tongue, and the relationship is satisfied: 1°≤∠AOK≤15°, 15°≤∠NOL≤30°.

[0013] Based on the above embodiments, the air volume and air inlet and outlet efficiency are guaranteed, and a low noise level is maintained.

[0014] In one embodiment, within the reference plane, the diameter of the wind wheel is φ, the rear volute tongue is arranged in an arc shape arched toward the wind wheel cavity, and the curvature radius R2 of the surface of the rear volute tongue satisfies the relationship: 0.03φ≤R2≤0.08φ.

[0015] Based on the above embodiments, the aerodynamic efficiency can be improved and the noise level can be kept low.

[0016] In one embodiment, the housing further comprises a plurality of guide ribs, the plurality of guide ribs are connected to the rear volute tongue and are arranged at intervals along the axis of the wind wheel;

[0017] Wherein, the guide rib is arranged in an arc shape arched toward the wind wheel cavity.

[0018] Based on the above embodiments, noise can be reduced, and the pressure loss of the airflow in the process of flowing to the air outlet can be reduced, thereby improving the user experience.

[0019] In one embodiment, the curvature radius R3 of the top surface of the guide rib satisfies the relationship: 0.03φ≤R3≤0.08φ; and / or,

[0020] The curvature radius R3 of the top surface of the guide rib is less than or equal to the curvature radius R2 of the surface of the rear volute tongue.

[0021] Based on the above embodiments, the aerodynamic efficiency can be improved, the noise level can be kept low, the cost can be reduced and the air volume can be guaranteed.

[0022] In one embodiment, within the reference plane, the diameter of the wind wheel is φ, the minimum distance between the surface of the rear volute tongue and the outer contour of the wind wheel is δ2, and the relationship is satisfied: 0.04φ≤δ2≤0.07φ; and / or,

[0023] In the reference plane, the diameter of the wind wheel is φ, and the shell also includes a plurality of guide ribs, which are arranged at intervals along the axis of the wind wheel and connected to the rear volute tongue. The minimum distance between the top surface of the guide rib and the outer contour of the wind wheel is δ3, and the relationship is satisfied: 0.04φ≤δ3≤0.07φ.

[0024] Based on the above embodiments, air flow leakage can be reduced, air volume can be guaranteed, and noise can be reduced.

[0025] In one embodiment, the front volute tongue is arranged in an arc shape arched toward the wind wheel cavity, and the curvature radius R1 of the surface of the front volute tongue satisfies the relationship: 2mm≤R1≤10mm; and / or,

[0026] In the reference plane, the diameter of the wind wheel is φ, the minimum distance between the front volute tongue surface and the outer contour of the wind wheel is δ1, and the relationship is satisfied: 0.04φ≤δ1≤0.07φ.

[0027] Based on the above embodiments, the air volume and the lower noise level are ensured in this way.

[0028] In one embodiment, the front volute tongue comprises:

[0029] An air guide portion is provided at the junction of the wind wheel cavity and the heat exchange cavity and is arched toward the wind wheel cavity; and

[0030] A front transition portion is located on a side of the wind guide portion close to the wind wheel cavity and connected to the top wall of the wind wheel cavity, wherein the front transition portion is higher than the dome of the wind guide portion;

[0031] Wherein, the front transition portion is arranged in a step shape, or the front transition portion is arched in a direction away from the wind wheel.

[0032] Based on the above embodiments, the air intake efficiency is improved in this way, so that the air flow transition is more uniform and smooth.

[0033] In one embodiment, the indoor unit further comprises a heat exchanger, the heat exchanger is disposed in the heat exchange chamber, and the heat exchanger comprises a first heat exchange tube and a second heat exchange tube sequentially arranged at intervals in a direction away from the wind wheel;

[0034] In the reference plane, the minimum distance between the outer contour of the wind wheel and the first heat exchange tube is d1, and the minimum distance between the outer contour of the wind wheel and the second heat exchange tube is d2, and the relationship is satisfied: d1≥15mm, and d2≥25mm.

[0035] Based on the above embodiments, the flow of the airflow near the heat exchanger side of the wind wheel can be improved, and the turbulent kinetic energy there can be reduced, thereby achieving a noise reduction effect.

[0036] In one embodiment, the housing comprises:

[0037] The casing is provided with an open bottom;

[0038] An air duct shell and a water receiving tray assembly are arranged in the casing, and the air duct shell is located above the water receiving tray assembly. The air duct shell, the water receiving tray assembly and the casing cooperate to define the heat exchange chamber, the wind wheel chamber and the pressure diffuser chamber which are connected in sequence. The air duct shell is provided with the front volute tongue, and the water receiving tray assembly is provided with the rear volute tongue; and

[0039] A panel is covered at the open portion and is provided with an air inlet and an air outlet which are arranged at intervals. The heat exchange cavity is connected to the air inlet, and the pressure diffusion cavity is connected to the air outlet.

[0040] Based on the above embodiments, the housing is relatively flat and occupies less space.

[0041] In one embodiment, the wind duct shell at least forms the rear side wall and the top wall of the wind wheel cavity. On the reference plane, one end of the top wall of the wind wheel cavity is connected to point A, and the other end is connected to the rear side wall of the wind wheel cavity. One end of the rear side wall of the wind wheel cavity away from the top wall of the wind wheel cavity is connected to the rear side wall of the diffuser cavity at point D.

[0042] Along the direction from point A to point D, the distance between the air duct housing and the rotation center O gradually increases.

[0043] Based on the above embodiments, the airflow is relatively smooth, and the loss along the way can be reduced, thereby improving the efficiency of the indoor unit.

[0044] In one embodiment, the junction of the rear side wall and the top wall of the wind wheel cavity is point C, and the distances of arc AJ, arc JC and arc CD relative to the rotation center O gradually increase;

[0045] Among them, 20°≤∠AOJ≤40°, 30°≤∠JOC≤80°, 40°≤∠COD≤60°.

[0046] Based on the above embodiments, the gas outlet efficiency is further improved.

[0047] In one embodiment, at least the rear side wall of the pressure diffuser cavity is inclined relative to the height direction of the installation environment, so that the gas flow area of ​​the pressure diffuser cavity gradually increases;

[0048] Therein, an angle θ13 is formed between the rear side wall of the pressure diffuser cavity and the axis S, and θ13 satisfies the relationship: 6°≤θ13≤12°.

[0049] Based on the above embodiments, the air supply distance is increased and the user experience is improved.

[0050] In a second aspect, an embodiment of the present application provides a HVAC system, including:

[0051] outdoor unit; and

[0052] In the indoor unit as described in any one of the above items, the indoor unit and the outdoor unit are connected through a pipeline.

[0053] In the embodiment of the present application, a front volute tongue and a rear volute tongue are formed in the shell and arranged on both sides of the wind wheel. The front volute tongue is arranged above the rear volute tongue, so that when the wind wheel rotates, the airflow between the heat exchange chamber and the wind wheel chamber, and between the wind wheel chamber and the pressure diffusion chamber are guided respectively, so as to achieve air intake and air outlet, and improve the smoothness of airflow. Further, in the reference plane perpendicular to the axial direction of the wind wheel, ∠AOJ is used to represent the position of the front volute tongue relative to the rotation center O of the wind wheel in the circumferential direction of the wind wheel, and ∠POL is used to represent the position of the rear volute tongue relative to the rotation center O of the wind wheel in the circumferential direction of the wind wheel, and by limiting the specific range values ​​of ∠AOJ and ∠POL, it is ensured that the position and spacing of the front volute tongue and the rear volute tongue relative to the wind wheel are more appropriate, and a reasonable air outlet range and air intake range are established, so that the indoor unit of the embodiment of the present application has a higher airflow efficiency, sufficient air volume, lower noise and smoother airflow while ensuring a thinner body thickness, thereby improving user experience. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0055] Figure 1 This is a structural schematic diagram of an indoor unit according to an embodiment of the present application;

[0056] Figure 2 for Figure 1 A schematic cross-sectional view of the middle indoor unit II;

[0057] Figure 3 This is a cross-sectional structural diagram of the indoor unit of the present application from another perspective;

[0058] Figure 4 for Figure 3 Schematic diagram of the enlarged structure at a in the middle;

[0059] Figure 5 for Figure 3 Schematic diagram of the enlarged structure at b in the middle;

[0060] Figure 6 This is a schematic cross-sectional structure diagram of another embodiment of the indoor unit of the present application.

[0061] Description of Figure Numbers:

[0062] 100, indoor unit; 10, shell; 101, heat exchange chamber; 103, wind wheel chamber; 105, pressure diffusion chamber; 11, casing; 12, panel; 121, air outlet; 122, air inlet; 13, air duct shell; 131, front volute tongue; 1311, air guide part; 1313, front transition part; 15, water receiving tray assembly; 151, water receiving tray body; 153, rear volute tongue; 30, guide rib; 50, wind wheel; 70, heat exchanger; 71, first heat exchange tube; 73, second heat exchange tube.

[0063] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0064] In order to make the objectives, technical solutions and advantages of the present application clearer, the following part will further describe the embodiments of the present application in detail in conjunction with the accompanying drawings.

[0065] When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present application. Instead, they are only examples of devices and methods consistent with some aspects of the present application as detailed in the attached claims.

[0066] In the description of the present application, it should be understood that the terms "first", "second", etc. are used for descriptive purposes only and should not be understood as indicating or implying relative importance. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to the specific circumstances. In addition, in the description of the present application, unless otherwise specified, "multiple" refers to two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. The character " / " generally indicates that the objects associated before and after are in an "or" relationship.

[0067] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used in this specification are only for the purpose of describing specific embodiments and are not intended to limit this application. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0068] On the one hand, an embodiment of the present application proposes a HVAC system. As one of the commonly used air conditioning equipment, the HVAC system is used to adjust the indoor ambient temperature (some HVAC systems also have functions such as adjusting humidity and purification). In the embodiment of the present application, the HVAC system includes but is not limited to equipment such as air conditioners, multi-split units and heat pumps, and can be used in large-scale places such as shopping malls and office buildings. Exemplarily, the HVAC system may include an indoor unit 100, an outdoor unit and a connecting pipe, and the indoor unit 100 is connected to the outdoor unit through a connecting pipe so that the indoor unit 100 and the outdoor unit form a circulation flow path. In some actual use scenarios, the indoor unit 100 of the present application can be installed indoors, the outdoor unit is responsible for cooling or heating, and the refrigerant is transported through the connecting pipe. The refrigerant is heat exchanged with the indoor air and the outdoor air respectively, and the indoor unit 100 is responsible for delivering cold air or hot air to the room to achieve the effect of cooling or heating.

[0069] Another aspect of the embodiment of the present application provides an indoor unit 100, which may include but is not limited to ceiling units, duct units, wall-mounted air conditioner indoor units, and vertical air conditioner indoor units. The installation method of the ceiling unit allows it to be hidden inside the ceiling of the building and does not occupy the available indoor space, which is particularly important for those use environments with limited space (such as offices, stores, and residences) and can effectively utilize the space.

[0070] Please refer to Figure 1 and Figure 2 In some embodiments of the present application, the indoor unit 100 includes a housing 10 , a heat exchanger 70 and a wind wheel 50 .

[0071] The outer contour of the housing 10 may be roughly in the shape of a cuboid, and has an up-down direction ZZ, a front-to-back direction YY, and a left-to-right direction XX, and the up-down direction ZZ, the front-to-back direction YY, and the left-to-right direction XX are arranged at an angle to each other. An air duct is formed in the housing 10, and the air duct includes a heat exchange chamber 101, a wind wheel chamber 103, and a pressure diffusion chamber 105 that are connected in sequence. The housing 10 also forms an air inlet 122 and an air outlet 121, wherein the air inlet 122 is connected to the heat exchange chamber 101, and the air outlet 121 is connected to the pressure diffusion chamber 105.

[0072] The heat exchanger 70 and the wind wheel 50 are arranged at intervals in the air duct along the air flow direction, and the heat exchanger 70 is located in the heat exchange chamber 101. Optionally, the heat exchanger 70 can be in a variety of shapes such as straight, V-shaped, arc-shaped or wavy. The heat exchanger 70 is used to exchange heat with the gas passing through the heat exchanger 70, and plays a role in cooling or heating the gas. For example, a plurality of refrigerant pipes are provided in the heat exchanger 70. When the gas passes through the heat exchanger 70, it exchanges heat with the refrigerant in the pipe, thereby changing the temperature of the gas. Specifically, when cooling, the gas exchanges heat with the refrigerant of the heat exchanger 70 to form low-temperature air; and when heating, the gas exchanges heat with the refrigerant of the heat exchanger 70 to form heated air.

[0073] The wind wheel 50 is arranged in the wind wheel cavity 103, and can extract the gas on one side of the heat exchange cavity 101, and work on it to make it flow to the pressure diffuser cavity 105 at a faster flow rate, providing power for the gas circulation in the air duct. The wind wheel 50 can be a crossflow wind wheel 50, a centrifugal wind wheel 50 or an axial flow wind wheel 50, etc. When the wind wheel 50 is configured as a crossflow wind wheel 50, the crossflow wind wheel 50 has the advantages of small radial size, low rotation speed, low noise, uniform air output, etc., and its axial length can be arbitrarily lengthened without affecting the gas flow state, etc., and compared with the centrifugal wind wheel 50 or the axial flow wind wheel 50, the cost of the crossflow wind wheel 50 is lower.

[0074] In such Figure 1 and Figure 2 In the ceiling machine shown, the air outlet 121 and the air inlet 122 are spaced apart on the bottom surface of the shell 10. When the indoor unit 100 is installed indoors, the bottom surface can be located on the ceiling and facing the indoors. Since the air outlet 121 and the air inlet 122 are both located on the bottom surface, the indoor unit 100 can inhale and discharge airflow on only one side, which is more conducive to the flat design of the indoor unit 100 and to achieve a thinner body thickness, so as to be suitable for environments with smaller installation spaces. After the airflow enters the ceiling machine from the air inlet 122, it needs to undergo a large airflow turn and flow out from the air outlet 121. The ceiling machine in the related art has low aerodynamic efficiency and high noise, which affects the user experience.

[0075] Please refer to Figure 2 and Figure 3 In the embodiment of the present application, the housing 10 is provided with a front volute tongue 131 and a rear volute tongue 153. The front volute tongue 131 is provided at the transition between the wind wheel cavity 103 and the heat exchange cavity 101, and the rear volute tongue 153 is provided at the transition between the pressure diffuser cavity 105 and the wind wheel cavity 103. Along the up-down direction ZZ, the front volute tongue 131 is located above the rear volute tongue 153, and the front volute tongue 131 and the rear volute tongue 153 are located on both sides of the wind wheel 50 along the front-back direction YY. In this way, when the indoor unit 100 is working, the wind wheel 50 rotates, and the airflow enters the heat exchange cavity 101 through the air inlet 122 and exchanges heat with the heat exchanger 70. Thereafter, the airflow flows to the wind wheel cavity 103 through the front volute tongue 131, and the rear volute tongue 153 is used to guide part of the airflow blown out by the wind wheel 50 to flow to the pressure diffuser cavity 105, and part of it flows back to the wind wheel cavity 103. The airflow in the pressure diffuser 105 is blown out into the room through the air outlet 121, thereby adjusting the indoor ambient temperature.

[0076] In some embodiments, the wind wheel 50 has a rotating shaft extending in the left-right direction XX. The front volute tongue 131 and the rear volute tongue 153 both extend in the left-right direction XX, and the length of the front volute tongue 131 and the rear volute tongue 153 in the left-right direction XX is greater than or equal to the length of the wind wheel 50 in the left-right direction XX, so as to ensure that the front volute tongue 131 and the rear volute tongue 153 can fully guide the airflow.

[0077] The plane perpendicular to the axial direction of the wind wheel 50 is set as the reference plane, or the normal of the reference plane is set along the left-right direction XX. In the reference plane, the rotation center of the wind wheel 50 is a point on its own rotation axis. The rotation center of the wind wheel 50 is set as point O, and the axis passing through the rotation center and extending along the height direction (up-down direction ZZ) of the installation environment is set as S. The front volute tongue 131 and the rear volute tongue 153 are respectively arranged on both sides of the axis S, and the axis S intersects the top wall and the bottom wall of the wind wheel cavity 103 at points J and P respectively.

[0078] Among them, the end point of the contour line of the front volute tongue 131 on the reference plane close to the axis S is point A, and the end point of the rear volute tongue 153 close to the axis S is point L. It can be understood that ∠AOJ indicates the angular position relationship of the front volute tongue 131 relative to the rotation center O of the wind wheel 50, in the circumferential direction of the wind wheel 50; correspondingly, ∠POL indicates the angular position relationship of the rear volute tongue 153 relative to the rotation center O of the wind wheel 50, in the circumferential direction of the wind wheel 50. The embodiment of the present application stipulates that ∠AOJ satisfies the relationship: 25°≤∠AOJ≤35°, and ∠POL satisfies the relationship: 15°≤∠POL≤30°

[0079] Specifically, for ∠AOJ, the size of ∠AOJ indicates the distance between the front volute tongue 131 and the axis S. If ∠AOJ is greater than 35°, there is a large distance between the front volute tongue 131 and the axis S, and the gap between the front volute tongue 131 and the wind wheel 50 is large, which has a greater impact on the air intake efficiency. If ∠AOJ is less than 25°, the gap between the front volute tongue 131 and the wind wheel 50 is small, which not only affects the air intake volume, but also reduces the depth of the front volute tongue 131 to affect the air intake efficiency, or raises the position of the front volute tongue 131, thereby increasing the thickness of the shell 10 in the vertical direction ZZ while ensuring no interference with the wind wheel 50. Therefore, the embodiment of the present application limits 25°≤∠AOJ≤35°, so that the thickness of the shell 10 is kept in a relatively low range while ensuring the air intake volume and air intake efficiency, meeting the requirements of thin design. ∠AOJ can be selected as 27°, 30°, 35°, etc.

[0080] For ∠POL, the size of ∠POL indicates the distance between the rear volute tongue 153 and the axis S. If ∠POL is greater than 30°, there is a large distance between the rear volute tongue 153 and the axis S, and the gap between the rear volute tongue 153 and the wind wheel 50 is large. Too large a gap can easily cause airflow leakage, thereby causing the attenuation of air volume. If ∠POL is less than 15°, the gap between the rear volute tongue 153 and the wind wheel 50 is small, which will increase the noise on the one hand, and on the other hand, while ensuring that there is no interference with the wind wheel 50, either reduce the depth of the rear volute tongue 153 to affect the air intake efficiency, or lower the position of the rear volute tongue 153, thereby increasing the thickness of the housing 10 in the up and down direction ZZ. Therefore, the embodiment of the present application limits 15°≤∠POL≤30°, which is not only convenient for controlling the thickness of the housing 10, but also enables the indoor unit 100 to have sufficient air volume and good air intake efficiency, and can also reduce the noise level. ∠POL can be selected as 15°, 18°, 25°, etc.

[0081] It can be understood that along the circumference of the wind wheel 50, it can be divided into the air inlet angle of the indoor unit 100, the envelope angle of the front volute tongue 131, the envelope angle of the rear volute tongue 153 and the air outlet angle of the indoor unit 100, wherein the envelope angle of the front volute tongue 131 and the envelope angle of the rear volute tongue 153 respectively represent the coverage of the front volute tongue 131 and the rear volute tongue 153 in the circumference of the wind wheel 50. When the envelope angle of the front volute tongue 131 and the envelope angle of the rear volute tongue 153 are constant, the position of the front volute tongue 131 and the rear volute tongue 153 in the circumference of the wind wheel 50 can be controlled by controlling the position of the front volute tongue 131 and the rear volute tongue 153 in the circumference of the wind wheel 50, such as limiting ∠AOJ and ∠POL to control the size of the air inlet angle and the air outlet angle. By controlling the reasonable ∠AOJ and ∠POL angle ranges, the air inlet angle and the air outlet angle can be controlled within a more appropriate range, so that the airflow can flow more smoothly and improve the user experience.

[0082] Therefore, the embodiment of the present application forms a front volute tongue 131 and a rear volute tongue 153 on both sides of the wind wheel 50 in the shell 10, and the front volute tongue 131 is arranged above the rear volute tongue 153, so that when the wind wheel 50 rotates, the airflow between the heat exchange chamber 101 and the wind wheel chamber 103, and the wind wheel chamber 103 and the pressure diffuser chamber 105 are guided respectively, so as to realize air intake and air outlet and improve the smoothness of airflow. Furthermore, in a reference plane perpendicular to the axial direction of the wind wheel 50, ∠AOJ is used to represent the position of the front volute tongue 131 in the circumferential direction of the wind wheel 50 relative to the rotation center O of the wind wheel 50, and ∠POL is used to represent the position of the rear volute tongue 153 in the circumferential direction of the wind wheel 50 relative to the rotation center O of the wind wheel 50, and by limiting the specific range values ​​of ∠AOJ and ∠POL, the position and spacing of the front volute tongue 131 and the rear volute tongue 153 relative to the wind wheel 50 are ensured to be more appropriate, and a reasonable air outlet range and air inlet range are established, so that the indoor unit 100 of the embodiment of the present application has higher airflow efficiency, sufficient air volume, lower noise and smoother airflow while ensuring a thinner body thickness, thereby improving user experience.

[0083] Further, in the reference plane, the end point of the front volute tongue 131 away from the axis S is point K, ∠KOL is the air inlet angle of the indoor unit 100, and the relationship is satisfied: 150°≤∠KOL≤170°. It can be understood that along the circumference of the wind wheel 50, it can be divided into the air inlet angle of the indoor unit 100, the envelope angle of the front volute tongue 131, the envelope angle of the rear volute tongue 153 and the air outlet angle of the indoor unit 100, wherein the envelope angle of the front volute tongue 131 and the envelope angle of the rear volute tongue 153 respectively represent the coverage of the front volute tongue 131 and the rear volute tongue 153 in the circumferential direction of the wind wheel 50. When the envelope angle of the front volute tongue 131 and the envelope angle of the rear volute tongue 153 are constant, the larger the air inlet angle is, the smaller the air outlet angle is.

[0084] Specifically, if ∠KOL is greater than 170°, the air inlet angle is too large and the air outlet angle is too small, and the airflow enters the impeller 50 at a faster speed, thereby conflicting with the airflow direction driven by the impeller 50 during operation, reducing the cross-flow area. At the same time, the airflow will generate vortices near the impeller 50, which increases the operating noise and reduces the performance of the air conditioner indoor unit 100. If ∠KOL is less than 150°, the air inlet angle is small and the air outlet angle is large, which will affect the smoothness of the air intake on the one hand, and on the other hand, the airflow blown out by the impeller 50 will enter the indoor environment in a more dispersed form, reducing the user experience. Therefore, in order to take into account both noise and air intake effects and ensure the user experience, the embodiment of the present application limits 150°≤∠KOL≤170°, and ∠KOL can be selected as 150°, 160°, 165°, etc.

[0085] Please refer to Figure 3 In some embodiments, the end point of the rear volute tongue 153 away from the axis S is point N. Therefore, ∠AOK is the envelope angle of the front volute tongue 131, ∠NOL is the envelope angle of the rear volute tongue 153, and the relationship is satisfied: 1°≤∠AOK≤15°, 15°≤∠NOL≤30°.

[0086] It can be understood that if ∠AOK is greater than 15°, that is, the front volute tongue 131 occupies a larger range in the circumferential direction of the wind wheel 50, which has a greater impact on the air intake efficiency; and if ∠AOK is less than 1°, the front volute tongue 131 does less work and cannot ensure the air volume. Therefore, in order to ensure the air volume and air intake efficiency, the embodiment of the present application limits 1°≤∠AOK≤15°, where ∠AOK can be selected as 8°, 10°, 13°, etc.

[0087] If ∠NOL is greater than 30°, that is, the rear volute tongue 153 occupies a larger range in the circumferential direction of the wind wheel 50, which will affect the air outlet efficiency and easily increase the noise; and if ∠NOL is less than 15°, the front volute tongue 131 does less work and cannot ensure the air volume. Therefore, in order to ensure the air volume and air outlet efficiency and maintain a low noise level, the embodiment of the present application limits 15°≤∠NOL≤30°, where ∠NOL can be selected as 15°, 19°, 20°, etc.

[0088] Please refer to Figure 3 and Figure 4 , observing the profile of the rear volute tongue 153 in the reference plane, the rear volute tongue 153 is arranged in an arc shape arched toward the wind wheel cavity 103, so as to separate the airflow, so that the airflow blown out by the wind wheel 50 can flow more smoothly to the diffuser cavity 105 or flow through the gap between the rear volute tongue 153 and the wind wheel 50. The diameter of the wind wheel 50 is φ, and φ can be specifically set according to the size of the housing 10. For example, in some structural forms, φ can be set to 98mm or 100mm, so as to ensure sufficient air volume while having a thinner housing 10.

[0089] In some embodiments, the radius of curvature of the surface of the rear volute tongue 153 is R2, and satisfies the relationship: 0.03φ≤R2≤0.08φ. It can be understood that the larger the radius of curvature, the flatter the rear volute tongue 153, and vice versa. The sharper it is. Specifically, if R2 is greater than 0.08φ, the diversion effect on the airflow is poor, and the aerodynamic efficiency is low; if R2 is less than 0.03φ, the airflow near the rear volute tongue 153 is more turbulent and the noise is greater. Therefore, in order to improve the aerodynamic efficiency and maintain a low noise level, the embodiment of the present application defines 0.03φ≤R2≤0.08φ, and R2 can be 0.03φ, 0.05φ, 0.08φ, etc. In the specific example, φ is 100mm, and R2 can be selected as 7.9mm.

[0090] In one embodiment, a plurality of guide ribs 30 are further provided on the surface of the rear volute tongue 153. Along the extension direction (left-right direction XX) of the rear volute tongue 153, the plurality of guide ribs 30 are convexly provided on the surface of the rear volute tongue 153 at intervals, and the guide ribs 30 are provided in an arc shape arched toward the wind wheel cavity 103. The airflow blown out by the wind wheel 50 during operation has a high velocity and is prone to noise. In this embodiment, the plurality of guide ribs 30 are convexly provided on the surface of the rear volute tongue 153 at intervals, so that when the airflow flows through the surface of the rear volute tongue 153, the airflow with noise will be separated, and compared with the airflow directly impacting the entire surface, the interference area between the airflow and the surface of the guide ribs 30 is smaller, thereby reducing noise, thereby improving the user experience. In addition, the arrangement direction (left-right direction XX) of the multiple guide ribs 30 is parallel to the axial direction of the wind wheel 50, and the extension direction of the guide ribs 30 is perpendicular to the axial direction of the wind wheel 50. In this way, under the guiding effect of the multiple guide ribs 30, the flow of airflow in the axial direction can be reduced, thereby reducing the pressure loss of the airflow during the flow process toward the air outlet 121.

[0091] Furthermore, the radius of curvature of the top surface of the guide rib 30 is R3, and satisfies the relationship: 0.03φ≤R3≤0.08φ. Similarly, if R3 is greater than 0.08φ, the diversion effect on the airflow is poor and the aerodynamic efficiency is low; if R3 is less than 0.03φ, the airflow near the rear volute tongue 153 is more turbulent and the noise is greater. Therefore, in order to improve the aerodynamic efficiency and maintain a low noise level, the embodiment of the present application specifies 0.03φ≤R3≤0.08φ, and R3 can be 0.03φ, 0.05φ, 0.08φ, etc.

[0092] In some structural forms, R3≤R2. In this way, the guide ribs 30 are provided to reduce noise while reducing the coverage area of ​​the guide ribs 30, thereby reducing costs and ensuring air volume. Specifically, if φ is 100 mm, R2 can be selected to be 7.9 mm, and R3 can be selected to be 6.0 mm.

[0093] Please refer to Figure 4 , within the reference plane, the minimum distance between the surface of the rear volute tongue 153 and the outer contour of the wind wheel 50 is δ2, and the relationship is satisfied: 0.04φ≤δ2≤0.07φ. It can be understood that if δ2 is greater than 0.07φ, the excessive gap between the rear volute tongue 153 and the wind wheel 50 will cause more serious airflow leakage, resulting in air volume attenuation; and if δ2 is less than 0.04φ, the gap between the rear volute tongue 153 and the wind wheel 50 is too small, the airflow is more turbulent, and the noise is greater. Therefore, in order to ensure the air volume and a lower noise level, the embodiment of the present application is limited to 0.04φ≤δ2≤0.07φ, where δ2 can be 0.04φ, 0.05φ, 0.06φ, etc.

[0094] Similarly, the minimum distance between the top surface of the guide rib 30 and the outer contour of the wind wheel 50 is δ3, 0.04φ≤δ3≤0.07φ, which will not be repeated. Specifically, when φ is 98 mm, δ2 can be selected as 6.4 mm, and δ3 can be selected as 5.1 mm.

[0095] Please refer again Figure 3 , the airflow flowing out from the rear volute 153 is located between the heat exchanger 70 and the wind wheel 50. The heat exchanger 70 includes a first heat exchange tube 71 and a second heat exchange tube 73 arranged in sequence and spaced apart in a direction away from the wind wheel 50. At least part of the first heat exchange tube 71 and the second heat exchange tube 73 extends along the left-right direction XX, and it can be understood that the heat exchanger 70 may not only include the first heat exchange tube 71 and the second heat exchange tube 73.

[0096] In the reference plane, the minimum distance between the outer contour of the wind wheel 50 and the first heat exchange tube 71 is d1, and the minimum distance between the outer contour of the wind wheel 50 and the second heat exchange tube 73 is d2, and the relationship is satisfied: d1 ≥ 15 mm, and d2 ≥ 25 mm. It can be understood that if d1 is less than 15 mm and d2 is less than 25 mm, the airflow returning from the rear volute tongue 153 interferes with the first heat exchange tube 71 and the second heat exchange tube 73 to generate turbulence, thereby increasing the noise of the indoor unit 100. Therefore, the embodiment of the present application defines d1 ≥ 15 mm, and d2 ≥ 25 mm, so as to improve the flow of the airflow near the side of the wind wheel 50 close to the heat exchanger 70, reduce the turbulent kinetic energy there, and thus play a role in noise reduction.

[0097] Please refer to Figure 3 and Figure 5 In some embodiments, the front volute tongue 131 is also arranged in an arc shape arched toward the wind wheel cavity 103 to facilitate airflow guidance. Among them, the curvature radius R1 of the surface of the front volute tongue 131 satisfies the relationship: 2mm≤R1≤10mm. If R1 is greater than 10mm, the work efficiency of the front volute tongue 131 is poor and the air intake efficiency is low; and if R1 is less than 2mm, the noise at the front volute tongue 131 is large. The embodiment of the present application limits 2mm≤R1≤10mm, which can reduce noise and ensure air intake efficiency. Among them, R1 can be selected as 6mm, 8mm, 10mm, etc.

[0098] Furthermore, the minimum distance between the surface of the front volute tongue 131 and the outer contour of the wind wheel 50 is δ1, and 0.04φ≤δ1≤0.07φ. It can be understood that if δ1 is greater than 0.07φ, the excessive gap between the front volute tongue 131 and the wind wheel 50 will cause serious airflow leakage, resulting in insufficient air intake; and if δ1 is less than 0.04φ, the gap between the front volute tongue 131 and the wind wheel 50 is too small, the airflow is relatively turbulent, and the noise is relatively large. Therefore, in order to ensure the air volume and a low noise level, the embodiment of the present application is limited to 0.04φ≤δ1≤0.07φ, where δ1 can be 0.04φ, 0.05φ, 0.06φ, etc. When φ is 98mm, δ1 can be selected as 4.8mm.

[0099] Please continue to refer to Figure 5 In one embodiment, the front volute tongue 131 includes an air guide portion 1311 and a front transition portion 1313. The air guide portion 1311 is disposed at the junction of the wind wheel cavity 103 and the heat exchange cavity 101, and is arched toward the wind wheel cavity 103. The front transition portion 1313 is located on the side of the air guide portion 1311 close to the wind wheel cavity 103, and is connected to the top wall of the wind wheel cavity 103. The front transition portion 1313 is higher than the arch of the air guide portion 1311. As a result, the distance between the front transition portion 1313 and the wind wheel 50 is large, and the airflow can be buffered when flowing through the front volute tongue 131, thereby improving the air intake efficiency.

[0100] Optionally, the front transition portion 1313 may be arranged in a stepped shape. Figure 5 As shown, the front transition portion 1313 can be extended in a generally horizontal direction, with one end thereof connected to the top wall of the wind wheel cavity 103, and the other end connected to the end of the wind guide portion 1311. Since the wind guide portion 1311 is arranged in an arc shape, there is a height difference between the front transition portion 1313 and the arch of the wind guide portion 1311, and the airflow can be buffered when flowing through the front transition portion 1313. Of course, in some structural forms with a larger envelope angle of the front volute tongue 131, the front transition portion 1313 can also be an arc shape that is arched in the direction away from the wind wheel 50, so as to make the airflow transition more uniform and smooth.

[0101] Combined with reference Figures 2 to 5 In some structural forms, the housing 10 includes a casing 11, a panel 12, an air duct casing 13 and a water receiving tray assembly 15.

[0102] The housing 11 may be made of alloy or metal such as aluminum or steel to meet requirements such as structural strength and long service life. Of course, the housing 11 may also be made of plastic to meet requirements such as light weight, and this application does not limit this. The housing 11 may play a protective role and be connected and adapted to the connection structure of the indoor environment.

[0103] The bottom of the casing 11 is open, and the panel 12 is covered at the open position, and the air inlet 122 and the air outlet 121 are arranged at intervals on the panel 12. The panel 12 is usually detachably connected to the bottom of the casing 11, so that it is easy to disassemble and assemble the panel 12. During the later use of the indoor unit 100, when the electrical components inside the casing 11 fail, the panel 12 can be removed, and then the electrical components inside the casing 11 can be repaired. The connection between the panel 12 and the casing 11 can be connected by threaded fasteners or by snap-on connection. Here, there is no specific restriction on the connection between the panel 12 and the casing 11.

[0104] The air duct shell 13 and the water receiving pan assembly 15 are arranged in the housing 11, and the air duct shell 13 is located above the water receiving pan assembly 15. The housing 11, the air duct shell 13 and the water receiving pan assembly 15 cooperate to form a heat exchange chamber 101, an air inlet chamber 103 and a pressure diffusion chamber 105 that are connected in sequence. The water receiving pan assembly 15 is configured to carry condensed water from the heat exchanger 70. During the operation of the indoor unit 100, condensed water usually adheres to the surface of the heat exchanger 70. Generally, in order to avoid the surface of the heat exchanger 70 being attached with more condensed water and affecting the performance of the heat exchanger 70 itself, a water receiving pan assembly 15 is arranged below the bottom of the heat exchanger 70 to receive the condensed water.

[0105] Further, the air duct shell 13 forms at least part of the top wall of the heat exchange chamber 101, the front volute tongue 131, the top wall and rear side wall of the wind wheel chamber 103, and the rear side wall of the pressure diffuser chamber 105. The water receiving tray assembly 15 includes a water receiving tray body 151 and a rear volute tongue 153, the rear volute tongue 153 is connected to the water receiving tray body 151, and the water receiving tray body 151 forms at least part of the bottom wall of the wind wheel chamber 103, at least part of the bottom wall of the heat exchange chamber 101, and the front side wall of the pressure diffuser chamber 105.

[0106] Please refer to Figure 6 On the reference plane, one end of the top wall of the wind wheel cavity 103 is connected to point A, and the other end is connected to the rear side wall of the wind wheel cavity 103. One end of the rear side wall of the wind wheel cavity 103 away from the top wall of the wind wheel cavity 103 is connected to the rear side wall of the diffuser cavity 105 at point D. Along the direction from point A to point D, the distance between the air duct shell 13 and the rotation center O gradually increases. As a result, the airflow is smoother in the process of moving from the wind wheel cavity 103 to the diffuser cavity 105, and the loss along the way can be reduced, thereby improving the efficiency of the indoor unit 100.

[0107] Further, in the height direction of the installation environment (vertical direction ZZ), point D is flush with the rotation center O, that is, the junction of the rear side wall of the wind wheel cavity 103 and the rear side wall of the diffuser cavity 105 is flush with the rotation center to ensure smooth airflow transition and reduce diffusion loss. In some embodiments, point D is also lower than the rotation center O, which is not limited here.

[0108] Please refer to Figure 6 In some embodiments, the junction of the rear side wall and the top wall of the wind wheel cavity 103 is point C, and the distances of arc AJ, arc JC and arc CD relative to the rotation center O gradually increase. 20°≤∠AOJ≤40°, 30°≤∠JOC≤80°, 40°≤∠COD≤60°.

[0109] Among them, on the reference plane, two circles with radii of 0.2φ and 0.3φ are drawn with the rotation center O as the center. With the forward and backward direction YY as the reference and the front as the positive direction, two rays with the origin at the rotation center O are drawn based on the clockwise rotation angles θ1 and θ2, respectively. The two rays intersect the two circles at F, H, E, and G, respectively. Connect FG and EH, and the intersection point is the center of the spiral line. From this point, a three-arc spiral line is drawn to obtain arcs AJ, JC, and CD. Among them, θ1 can be selected as 130° and θ2 can be selected as 140°.

[0110] It can be understood that when ∠AOJ is greater than 40°, it affects the smoothness of the air intake, and when ∠AOJ is less than 20°, it may cause a large airflow turn, causing a large loss along the way; when ∠JOC is greater than 80°, it affects the smoothness of the air outlet, and when ∠JOC is less than 30°, it may cause a large airflow turn, causing a large loss along the way; when ∠COD is greater than 60°, it affects the volume of the diffusion chamber 105, resulting in insufficient static pressure conversion, and when ∠COD is less than 40°, it may cause a large airflow turn, causing a large loss along the way. Therefore, in order to ensure the smoothness of the air intake and outlet, while maintaining the stability of the airflow, gradually converting the kinetic energy into static pressure energy, and reducing the diffusion loss, the present application limits 20°≤∠AOJ≤40°, 30°≤∠JOC≤80°, and 40°≤∠COD≤60°. Among them, ∠AOJ can be selected as 20°, 30°, 35°, etc.; ∠JOC can be selected as 30°, 35°, 50°, etc.; ∠COD can be selected as 40°, 45°, 55°, etc.

[0111] Please refer to Figure 6In one embodiment, the rear side wall of the pressure diffuser 105 is tilted relative to the height direction (up and down direction ZZ) of the installation environment so that the gas flow area of ​​the pressure diffuser 105 gradually increases, and the kinetic energy is gradually converted into static pressure energy, thereby increasing the air supply distance. Among them, the rear side wall is at an angle θ13 relative to the axis S, or the up and down direction ZZ, and θ13 satisfies the relationship: 6°≤θ13≤12°. It can be understood that if θ13 is less than 6°, the kinetic energy of the airflow cannot be well converted into static pressure energy, resulting in a shorter air supply distance, excessive wind speed at the air outlet 121, and poor user experience. If θ13 is greater than 12°, the air outlet direction is relatively scattered, and a good air outlet effect cannot be achieved. Therefore, the embodiment of the present application limits 6°≤θ13≤12° to ensure the air supply distance and improve user experience. The above is an explanation of the specific structure of the indoor unit 100 in the embodiment of the present application. It can be understood that since the HVAC system of the present application adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought by the technical solutions of the above embodiments, which will not be repeated here one by one.

[0112] The same or similar numbers in the drawings of this embodiment correspond to the same or similar parts; in the description of this application, it should be understood that if the terms "up", "down", "left", "right", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the drawings, it is only for the convenience of describing this application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, the terms describing the positional relationship in the drawings are only used for illustrative purposes and cannot be understood as limitations on this application. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0113] The above are only preferred embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. An indoor unit, characterized in that: include: The housing is provided with a heat exchange chamber, a wind wheel chamber and a pressure diffuser chamber which are connected in sequence, and comprises a front volute tongue and a rear volute tongue, wherein the front volute tongue is arranged at the transition between the wind wheel chamber and the heat exchange chamber, and the rear volute tongue is arranged at the transition between the pressure diffuser chamber and the wind wheel chamber, and the front volute tongue is located above the rear volute tongue; and A wind wheel, located between the front volute tongue and the rear volute tongue; A plane perpendicular to the axial direction of the wind wheel is set as a reference plane. Within the reference plane, the rotation center of the wind wheel is point O, and the axis passing through the rotation center and extending along the height direction of the installation environment is S. The front volute tongue and the rear volute tongue are respectively arranged on both sides of the axis S. The axis S intersects with the top wall and the bottom wall of the wind wheel cavity at points J and P respectively. The end point of the front volute tongue close to the axis S is point A, and the end point of the rear volute tongue close to the axis S is point L. ∠AOJ satisfies the relationship: 25°≤∠AOJ≤35°, and ∠POL satisfies the relationship: 15°≤∠POL≤30°.

2. The indoor unit according to claim 1, characterized in that: In the reference plane, the end point of the front volute tongue away from the axis S is point K, ∠KOL is the air inlet angle of the indoor unit, and the relationship is satisfied: 150°≤∠KOL≤170°.

3. The indoor unit according to claim 2, characterized in that: The end point of the rear volute tongue away from the axis S is point N; ∠AOK is the envelope angle of the front volute tongue, ∠NOL is the envelope angle of the rear volute tongue, and the relationship is satisfied: 1°≤∠AOK≤15°, 15°≤∠NOL≤30°.

4. The indoor unit according to claim 1, characterized in that: In the reference plane, the diameter of the wind wheel is φ, the rear volute tongue is arranged in an arc shape arched toward the wind wheel cavity, and the curvature radius R2 of the surface of the rear volute tongue satisfies the relationship: 0.03φ≤R2≤0.08φ.

5. The indoor unit according to claim 4, characterized in that: The housing further comprises a plurality of guide ribs, which are connected to the rear volute tongue and are arranged at intervals along the axis of the wind wheel; Wherein, the guide rib is arranged in an arc shape arched toward the wind wheel cavity.

6. The indoor unit according to claim 5, characterized in that: The curvature radius R3 of the top surface of the guide rib satisfies the relationship: 0.03φ≤R3≤0.08φ; and / or, The curvature radius R3 of the top surface of the guide rib is less than or equal to the curvature radius R2 of the surface of the rear volute tongue.

7. The indoor unit according to claim 1, characterized in that: In the reference plane, the diameter of the wind wheel is φ, the minimum distance between the surface of the rear volute tongue and the outer contour of the wind wheel is δ2, and the relationship is satisfied: 0.04φ≤δ2≤0.07φ; and / or, In the reference plane, the diameter of the wind wheel is φ, and the shell also includes a plurality of guide ribs, which are arranged at intervals along the axis of the wind wheel and connected to the rear volute tongue. The minimum distance between the top surface of the guide rib and the outer contour of the wind wheel is δ3, and the relationship is satisfied: 0.04φ≤δ3≤0.07φ.

8. The indoor unit according to claim 1, characterized in that: The front volute tongue is arranged in an arc shape arched toward the wind wheel cavity, and the curvature radius R1 of the surface of the front volute tongue satisfies the relationship: 2mm≤R1≤10mm; and / or, In the reference plane, the diameter of the wind wheel is φ, the minimum distance between the front volute tongue surface and the outer contour of the wind wheel is δ1, and the relationship is satisfied: 0.04φ≤δ1≤0.07φ.

9. The indoor unit according to claim 1, characterized in that: The front volute tongue comprises: An air guide portion is provided at the junction of the wind wheel cavity and the heat exchange cavity and is arched toward the wind wheel cavity; and A front transition portion, located on a side of the wind guide portion close to the wind wheel cavity and connected to the top wall of the wind wheel cavity, wherein the front transition portion is higher than the dome of the wind guide portion; Wherein, the front transition portion is arranged in a step shape, or the front transition portion is arched in a direction away from the wind wheel.

10. The indoor unit according to claim 1, characterized in that: The indoor unit further comprises a heat exchanger, the heat exchanger being arranged in the heat exchange cavity, the heat exchanger comprising a first heat exchange tube and a second heat exchange tube sequentially arranged at intervals in a direction away from the wind wheel; In the reference plane, the minimum distance between the outer contour of the wind wheel and the first heat exchange tube is d1, and the minimum distance between the outer contour of the wind wheel and the second heat exchange tube is d2, and the relationship is satisfied: d1≥15mm, and d2≥25mm.

11. The indoor unit according to any one of claims 1 to 10, characterized in that: The housing comprises: The casing is provided with an open bottom; An air duct shell and a water receiving tray assembly are arranged in the casing, and the air duct shell is located above the water receiving tray assembly. The air duct shell, the water receiving tray assembly and the casing cooperate to define the heat exchange chamber, the wind wheel chamber and the pressure diffuser chamber which are connected in sequence. The air duct shell is provided with the front volute tongue, and the water receiving tray assembly is provided with the rear volute tongue; and A panel is covered at the open portion and is provided with an air inlet and an air outlet which are arranged at intervals. The heat exchange cavity is connected to the air inlet, and the pressure diffusion cavity is connected to the air outlet.

12. The indoor unit according to claim 11, characterized in that: The wind duct shell at least forms the rear side wall and the top wall of the wind wheel cavity. On the reference plane, one end of the top wall of the wind wheel cavity is connected to point A, and the other end is connected to the rear side wall of the wind wheel cavity. One end of the rear side wall of the wind wheel cavity away from the top wall of the wind wheel cavity is connected to the rear side wall of the diffuser cavity at point D. Along the direction from point A to point D, the distance between the air duct housing and the rotation center O gradually increases.

13. The indoor unit according to claim 12, characterized in that: The junction of the rear side wall and the top wall of the wind wheel cavity is point C, and the distances of arc AJ, arc JC and arc CD relative to the rotation center O gradually increase; Among them, 20°≤∠AOJ≤40°, 30°≤∠JOC≤80°, 40°≤∠COD≤60°.

14. The indoor unit according to any one of claims 1 to 10, characterized in that: At least the rear side wall of the pressure diffuser cavity is arranged to be inclined relative to the height direction of the installation environment so that the gas flow area of ​​the pressure diffuser cavity is gradually increased; Therein, an angle θ13 is formed between the rear side wall of the pressure diffuser cavity and the axis S, and θ13 satisfies the relationship: 6°≤θ13≤12°.

15. A HVAC system, characterized in that: include: Outdoor unit; and The indoor unit according to any one of claims 1 to 14, wherein the indoor unit and the outdoor unit are connected via a pipeline.

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