Air conditioner indoor unit and heating and ventilation system

Abstract

The utility model discloses an air conditioner indoor unit and a heating and ventilation system, and relates to the technical field of heating and ventilation systems.The air conditioner indoor unit comprises a machine shell and an electric heating assembly; an air duct is formed in the shell; the electric heating assembly is arranged in the air channel and comprises electric heating pieces and an installation base, the installation base is connected with the machine shell and comprises a flame-retardant part and an installation part, the installation part is connected to the flame-retardant part, and the electric heating pieces are connected to the installation part and arranged on one side of the flame-retardant part at intervals. According to the technical scheme, the electric heating assembly is connected with the machine shell through the installation base, installation of the electric heating assembly is convenient, meanwhile, the installation base is composed of the flame-retardant part and the installation part, and the structure is simple.

Description

Technical Field

[0001] This application relates to the technical field of HVAC systems, and particularly to an air conditioner indoor unit and an HVAC system. Background Art

[0002] The HVAC system covers a wide variety of equipment, such as air conditioners, multi-connected units, heat pumps, water heaters, etc., and the HVAC system includes an indoor unit and an outdoor unit. Among them, an electric heating component is usually installed in the indoor unit to improve the heating efficiency.

[0003] In the related art, the electric heating component is generally fixedly installed in the casing and is respectively provided with a flame retardant component and a mounting component, etc., to achieve the two functions of installing the heating element and fire protection. Such a setting makes the components at the electric auxiliary heating position more, and also causes more components in the indoor unit, and the structure is relatively complex. Utility Model Content

[0004] The embodiments of this application provide an air conditioner indoor unit and an HVAC system, which can realize the convenient installation of the electric heating component, reduce parts, so that the overall structure of the air conditioner indoor unit is also simplified.

[0005] In a first aspect, the embodiments of this application provide an air conditioner indoor unit, which includes a casing and an electric heating component. A wind channel is formed in the casing; the electric heating component is arranged in the wind channel and includes an electric heating element and a mounting seat. The mounting seat is connected to the casing. The mounting seat includes a flame retardant part and a mounting part. The mounting part is connected to the flame retardant part. The electric heating element is connected to the mounting part and is spaced apart from one side of the flame retardant part.

[0006] In some embodiments, the flame retardant part includes a flame retardant plate, and the mounting part includes two mounting plates. The two mounting plates are spaced apart in the length direction of the flame retardant plate; both ends of the electric heating element are detachably connected to the two mounting plates.

[0007] In some embodiments, the flame retardant part and the mounting part are of an integral structure.

[0008] In some embodiments, both the flame retardant part and the mounting part are made of sheet metal.

[0009] In some embodiments, the width dimension of the flame retardant plate is greater than the width dimension of the electric heating element.

[0010] In some embodiments, the flame retardant plate includes a plate body, and reinforcing ribs are further arranged on the plate body.

[0011] In some embodiments, a part of the reinforcing rib passes through the connection part of the mounting plate and the plate body and extends to the mounting plate.

[0012] In some of these embodiments, one of the flame-retardant board and the casing is provided with a clamping convex portion, and the other of the two is provided with a clamping concave portion, and the clamping convex portion and the clamping concave portion are in clamping fit; and / or, the flame-retardant board and the casing are respectively provided with a mounting hole and a connection hole, and the mounting hole and the connection hole are detachably connected through a connecting member.

[0013] In some of these embodiments, one end of the electric heating element is inserted into one of the mounting plates, and the other end of the electric heating element is detachably connected to the other mounting plate through a connecting member.

[0014] In some of these embodiments, the indoor air conditioner includes a heat exchanger disposed in the air duct, and the electric heating assembly is disposed on the air outlet side of the heat exchanger; the electric heating element is arranged in a long strip shape, and the length extension direction of the electric heating element is parallel to the width direction of the heat exchanger.

[0015] In some of these embodiments, the electric heating element is arranged in a flat plate shape, and the electric heating element includes two plate surfaces opposite to each other in the thickness direction; wherein, the plate surface of the electric heating element is parallel to the air outlet surface of the heat exchanger; or, the plate surface of the electric heating element is arranged at an angle with the air outlet surface of the heat exchanger.

[0016] In a second aspect, an embodiment of the present application provides a heating and ventilation system, and the heating and ventilation system includes the indoor air conditioner as described above.

[0017] Based on the indoor air conditioner of the embodiment of the present application, the mounting seat is connected to the casing. The mounting seat includes a flame-retardant portion and a mounting portion. The mounting portion is connected to the flame-retardant portion. The electric heating element is connected to the mounting portion and is spaced apart from one side of the flame-retardant portion. In this way, the electric heating element can be quickly installed. When maintaining or replacing the electric heating assembly, operations such as disassembling and assembling the mounting seat can be directly performed on the casing. At the same time, this structure can also improve the structural integrity of the electric heating assembly, has a relatively simple structure, reduces production costs. Of course, this also reduces the number of components of the indoor air conditioner and simplifies the overall structure. The flame-retardant portion can isolate the heat-generating part and the wiring part of the electric heating element from other components, reduce the contact between the electric heating element and other components, and reduce the risk of other equipment being damaged by heat or even catching fire due to excessive temperature. Connecting the electric heating element to the mounting portion and spacing the electric heating element from the flame-retardant portion further reduces the possibility of the electric heating element contacting and conducting heat with other components, and at the same time can facilitate the air supply in the air duct to contact the electric heating element more fully, thereby improving the heating efficiency. Description of the Drawings

[0018] To more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on the structures shown in these drawings.

[0019] Figure 1 It is a schematic structural diagram of an embodiment of an air conditioner indoor unit of the present application;

[0020] Figure 2 is Figure 1 an exploded view of the air conditioner indoor unit shown in;

[0021] Figure 3 is Figure 1 a schematic structural diagram of another perspective of the air conditioner indoor unit shown in;

[0022] Figure 4 is Figure 1 a schematic structural diagram of the electric heating component of the air conditioner indoor unit shown in;

[0023] Figure 5 is Figure 4 an exploded view of the electric heating component shown in.

[0024] Explanation of the reference numerals in the drawings:

[0025] 1. Air conditioner indoor unit; 10. Cabinet; 11. Air duct; 111. Air outlet; 12. Clamping convex part; 13. Connecting part; 20. Electric heating component; 21. Electric heating element; 22. Mounting seat; 23. Flame retardant part; 231. Flame retardant plate; 232. Plate body; 2321. Reinforcing rib; 233. Clamping concave part; 234. Mounting hole; 24. Mounting part; 241. Mounting plate; 30. Heat exchanger.

[0026] The realization of the purpose of the present application, functional features and advantages will be further described in combination with the embodiments with reference to the drawings. Specific embodiments

[0027] To make the purpose, technical solutions and advantages of the present application clearer, the following will further describe the embodiments of the present application in detail in conjunction with the drawings.

[0028] When the following description involves 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. On the contrary, they are only examples of the devices and methods consistent with some aspects of the present application as detailed in the appended claims.

[0029] In the description of the present application, it should be understood that terms such as "first", "second", etc. are only used for descriptive purposes and cannot be construed 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 specific circumstances. In addition, in the description of the present application, unless otherwise specified, "a plurality of" means two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships can exist. For example, A and / or B can represent three situations: A exists alone, A and B exist simultaneously, and B exists alone. The character " / " generally indicates that the associated objects before and after are in an "or" relationship.

[0030] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which this application belongs. The terms used in the description of 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.

[0031] The HVAC system covers a wide variety of equipment, such as air conditioners, multi-connected units, heat pumps, water heaters, etc., and the HVAC system includes an indoor unit and an outdoor unit. Among them, an electric heating component is usually installed in the indoor unit to improve the heating efficiency.

[0032] In the related art, the electric heating component is generally fixedly installed in the casing, and correspondingly configured with a flame retardant component and an installation component, etc., for fire protection and installation of the heating electric heating element. In this way, there are more components for electric auxiliary heating, resulting in a more complex installation of the electric heating component.

[0033] To solve the above problems, please refer to Figures 1 to 3 In the first aspect of the present application, an air conditioner indoor unit 1 is proposed. In the embodiment of the present application, the air conditioner indoor unit 1 includes a casing 10, an electric heating component 20, and a heat exchanger 30.

[0034] The casing 10 can be an integrally formed structure to improve the overall strength of the casing 10. The casing 10 can be made of materials with higher strength such as stainless steel, aluminum alloy, plastic, etc., to better protect the various functional components arranged inside the casing 10. The present application does not limit this. A wind channel 11 is formed inside the casing 10. Among them, the casing 10 is provided with an air outlet 111 and a return air port (not shown) that communicate with the wind channel 11 in the flowing direction of the air flow. It should be noted here that Figures 1 to 3Part of the structure of the housing 10 is shown, and the air outlet 111 is a schematic position. The electric heating component 20 and the heat exchanger 30 are arranged in the air duct 11. Further, a wind wheel (not shown) is also arranged in the housing 10. The wind wheel is arranged adjacent to the air outlet 111. Driven by the wind wheel, the air flow enters the air duct 11 through the air return opening and is discharged from the air outlet 111. During the flow of the air flow in the air duct 11, it will come into contact with the electric heating component 20 and the heat exchanger 30.

[0035] The electric heating component 20 includes an electric heating element 21 and a mounting seat 22. The electric heating element 21 can directly heat the air flowing through it, thereby improving the overall heating capacity and heating efficiency of the air conditioner indoor unit 1. In practical applications, as the heating element of the electric heating component 20, the electric heating element 21 can adopt PTC (Positive Temperature Coefficient) material, which is a semiconductor heating ceramic. When the external temperature decreases, the resistance value of the PTC decreases, and the heat generation amount increases instead, so as to achieve a better heating effect. At the same time, it also has the characteristics of long service life, safe and reliable performance, etc. It can be understood that the electric heating element 21 can also adopt other types of heating structure forms, such as heating tubes, heating resistance wires, heating films, etc. This application does not limit this.

[0036] The mounting seat 22 is connected to the housing 10. The mounting seat 22 includes a flame retardant part 23 and a mounting part 24. The mounting part 24 is connected to the flame retardant part 23. The electric heating element 21 is connected to the mounting part 24 and is arranged at one side of the flame retardant part 23 at intervals. In this way, the electric heating element 21 can be quickly installed. When maintaining or replacing the electric heating component 20, operations such as disassembling and assembling the mounting seat 22 can be directly carried out on the housing 10. At the same time, this structure can also improve the structural integrity of the electric heating component 20, has a relatively simple structure, and reduces production costs. The flame retardant part 23 can isolate the heating part and the wiring part of the electric heating element 21 from other components, reducing the contact between the electric heating element 21 and other components, and the risk of other equipment being damaged by heat or even catching fire due to excessive temperature. Connecting the electric heating element 21 to the mounting part 24 and spacing the electric heating element 21 from the flame retardant part 23 further reduces the possibility of the electric heating element 21 contacting and conducting heat with other components, and at the same time can also facilitate the air supply in the air duct 11 to contact the electric heating element 21 more fully, thereby improving the heating efficiency.

[0037] It can be understood that the air conditioner indoor unit 1 of the present application can be a ceiling-mounted unit, which belongs to the indoor part of a central air conditioner. It can be understood that the central air conditioner is a situation where one outdoor unit serves multiple indoor units. Of course, the air conditioner indoor unit 1 can also be in the form of a one-to-one household air conditioner, such as a wall-mounted indoor unit. The electric heating component 20 is connected to the casing 10 to be arranged in the air duct 11. The electric heating component 20 is used to heat the air flowing through the air duct 11 to form hot air and discharge it from the air outlet 111. In the present application, the electric heating component 20 is arranged on the air outlet side of the heat exchanger 30. Taking the ceiling-mounted unit as an example, when the ceiling-mounted unit starts the heating function, the electric heating component 20 can be started separately to heat the air flowing through the air duct 11 in the case where the heating power demand is not high. Of course, the electric heating component 20 can also be used for auxiliary heating, that is, the air flow in the air duct 11 can first be heated by the heat exchanger 30, and the electric heating component 20 further heats the heated air flow, so as to meet the case where the heating power demand is relatively high.

[0038] As Figure 3 shown, the length extension direction of the electric heating element 21 is parallel to the width direction of the heat exchanger 30. Specifically, the heat exchanger 30 is arranged adjacent to the air return opening. Among them, the heat exchanger 30 can be a single-fold plate heat exchanger or a multi-fold plate heat exchanger. In the case where it is a single-fold plate heat exchanger, the heat exchanger 30 is inclined above the air return opening, and in the present application, the projection of the heat exchanger 30 in the horizontal direction is at least partially located in the air return opening. Furthermore, the electric heating component 20 can be arranged between the air wheel and the heat exchanger 30, so that the hot air flow in the air duct 11 can be sucked from the air return opening to the air outlet 111, improving the overall smoothness of the air flow direction.

[0039] Specifically, the electric heating element 21 is arranged in a long strip shape. The electric heating element 21 has a heating surface extending along its length direction, and the heat exchanger 30 has a heat exchange surface extending along its width direction. The length extension direction of the electric heating element 21 is parallel to the width direction of the heat exchanger 30, that is, the heating surface of the electric heating element 21 is parallel to the heat exchange surface of the heat exchanger 30. In this way, the air supply volume between the two can be increased, and the heating efficiency can be improved. Of course, an included angle can also be formed between the heating surface and the heat exchange surface. The included angle can be selected from 0° to 45°. In this way, the air supply volume between the heating surface and the heat exchange surface can also be ensured. When the above included angle is greater than 45°, the electric heating element 21 and / or the heat exchanger 30 will occupy too much height inside the casing, and then the body of the air conditioner indoor unit 1 will be bloated. Therefore, the included angle that can be formed between the heating surface and the heat exchange surface can be selected as 10°, 15°, 30° or 45°, etc. The present application does not limit this.

[0040] In another embodiment, the electric heating element 21 is arranged in a flat plate shape, and the electric heating element 21 includes two plate surfaces opposite to each other in the thickness direction. The plate surfaces can be PTC heating elements, and the plate surfaces of the electric heating element 21 are parallel to the air outlet surface of the heat exchanger 30; alternatively, the plate surfaces of the electric heating element 21 are arranged at an angle with the air outlet surface of the heat exchanger 30, and the angle can be selected to be set between 0° and 90°. That is, when the angle between the plate surface of the electric heating element 21 and the air outlet surface of the heat exchanger 30 is 90°, the plate surface of the electric heating element 21 is perpendicularly arranged with the inner wall surface of the housing 10 connecting the mounting seat 22. In this way, it can adapt to the air field conditions of different air volumes of the air conditioner indoor unit 1 and match different installation requirements.

[0041] In one embodiment, the flame retardant part 23 and the mounting part 24 are of an integral structure. In this way, the overall structural strength of the mounting seat 22 can be enhanced, and the operation steps when connecting the mounting seat 22 to the housing 10 can be reduced, thereby enabling the quick installation of the electric heating assembly 20 and also reducing labor costs. Of course, the flame retardant part 23 and the mounting part 24 can also be two separate components, and their connection can be a fixed connection such as welding, etc., or a detachable connection such as snap connection, screw connection, etc. The present application does not limit this.

[0042] In addition, both the flame retardant part 23 and the mounting part 24 are made of sheet metal material, which has the characteristics of light weight, high strength, conductivity, low cost, large-scale mass production, and good fire and heat insulation performance, and can make the mounting seat 22 have high material strength. Optionally, the sheet metal material can be cold-rolled sheet SPCC, galvanized steel sheet SECC, stainless steel, etc. Of course, the flame retardant part 23 and the mounting part 24 can also be other materials such as high-temperature resistant plastics, ceramics, etc. The present application does not limit this.

[0043] Please refer to Figures 3 to 5 , the flame retardant part 23 includes a flame retardant plate 231, and the mounting part 24 includes two mounting plates 241. The two mounting plates 241 are arranged at intervals in the length direction of the flame retardant plate 231. The flame retardant plate 231 is made of a flame retardant material, and the electric heating element 21 is placed on the side of the flame retardant plate 231 away from the housing 10, which can effectively isolate the electric heating element 21 from other components on the other side and play a role in heat insulation and fire prevention. To ensure the fire prevention effect, in one embodiment, the width dimension of the flame retardant plate 231 is greater than the width dimension of the electric heating element 21, so that the projection of the electric heating element 21 on the inner wall of the housing 10 is completely within the dimension range of the flame retardant plate 231, which can ensure the isolation of the electric heating element 21 from other components by the flame retardant plate 231, thereby improving the fire prevention effect.

[0044] Both ends of the electric heating element 21 are detachably connected to two mounting plates 241 respectively. The mounting plates 241 are integrally formed with the flame retardant plate 231 and are made of the same material. Therefore, while fixing and installing both ends of the electric heating element 21, the heat insulation and fire prevention effects on both sides of the electric heating element 21 can also be achieved. Specifically, one end of the electric heating element 21 is inserted into one mounting plate 241, and the other end of the electric heating element 21 is detachably connected to the other mounting plate 241 through a connecting member. With such a setting, it is convenient to quickly install the electric heating element 21, and at the same time, the use of connecting members such as screws for fixing is reduced, thereby reducing the production cost.

[0045] Specifically, a plugging hole is formed on one of the mounting plates 241, and a threaded hole is formed on the other mounting plate 241. Correspondingly, both ends of the electric heating element 21 further include pins. When installing the electric heating element 21, one of the pins of the electric heating element 21 is in threaded fit with the threaded hole, thereby locking one end of the electric heating element 21 to the mounting plate 241; and the other pin of the electric heating element 21 is inserted into and limited by the plugging hole on the mounting plate 241, so that the detachable connection between both ends of the electric heating element 21 and the two mounting plates 241 can be realized. Moreover, the present application does not limit the number and arrangement mode of the above hole structures for detachable connection on the mounting plate 241.

[0046] In an embodiment, one of the flame retardant plate 231 and the housing 10 is provided with a clamping convex portion 233, and the other is provided with a clamping concave portion 12, and the clamping convex portion 233 and the clamping concave portion 12 are in clamping fit. Exemplarily shown, the flame retardant plate 231 is provided with the clamping convex portion 233, and the housing 10 is provided with the clamping concave portion 12. Through the alignment and cooperation of the clamping concave portion 12 and the clamping convex portion 233, the quick alignment and assembly of the electric heating assembly 20 and the housing 10 can be realized, saving installation man-hours and reducing costs. And / or, the flame retardant plate 231 and the housing 10 are respectively provided with a mounting hole 234 and a connecting hole, and the mounting hole 234 and the connecting hole are detachably connected through a connecting member to provide various mounting methods of the mounting seat 22 on the housing 10, improving the mounting stability and alignment accuracy. Among them, the orientations of the mounting hole 234 and the connecting hole can be towards the outside of the housing 10 to facilitate the installation and maintenance of the electric heating assembly 20.

[0047] Please refer to again Figure 4 and Figure 5, in one embodiment, the flame retardant board 231 includes a board body 232, and reinforcing ribs 2321 are further provided on the board body 232 to enhance the structural strength of the board body 232, thereby enhancing the support strength and stability of the entire mounting seat 22. Moreover, a part of the reinforcing rib 2321 passes through the connection between the mounting plate 241 and the board body 232 and extends onto the mounting plate 241 to enhance the overall strength of the mounting plate 241 and the board body 232 of the flame retardant board 231, and at the same time, it can also prevent the connection angle between the mounting plate 241 and the board body 232 of the flame retardant board 231 from being deformed easily.

[0048] After the electric heating component 20 is installed in the air duct 11, there is a gap between the mounting plate 241 and the housing 10 that forms the side wall of the air duct 11. It can be understood that during the operation of the wind wheel, the air flow in the air duct 11 is mainly concentrated in the middle area of the air duct 11, while the air flow at the edge of the air duct 11 is relatively thin. Therefore, after the electric heating component 20 of the present application is installed, the setting with a gap between the mounting plate 241 and the housing 10 that forms the side wall of the air duct 11 can enable the electric heating component 20 to exchange heat with the air flow in the air duct 11 more fully and improve the heating efficiency even when the electric heating component 20 is not very long enough to completely occupy the width direction of the air duct 11.

[0049] The present application also proposes a heating and ventilation system, which includes the air conditioner indoor unit 1 as described above. The specific structure of the air conditioner indoor unit 1 refers to the above embodiments. Since the heating and ventilation system of the present application adopts all the technical solutions of the above all embodiments, it at least has all the beneficial effects brought by the technical solutions of the above embodiments, which will not be elaborated one by one here. Among them, the heating and ventilation system of the present application includes but is not limited to devices such as air conditioners, multi-connected units, heat pumps, water heaters, etc.

[0050] In the drawings of this embodiment, the same or similar reference numerals correspond to the same or similar components; in the description of the present application, it should be understood that if there are terms such as "upper", "lower", "left", "right", etc. indicating the orientation or positional relationship, they are based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, the terms describing the positional relationship in the drawings are only for illustrative purposes and cannot be understood as a limitation to the present application. For those of ordinary skill in the art, the specific meanings of the above terms can be understood according to specific circumstances.

[0051] The above are only the preferred embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. An air conditioner indoor unit, characterized in that: include a casing, wherein an air duct is formed; as well as An electric heating component is arranged in the air duct, including an electric heating element and a mounting seat, the mounting seat is connected to the casing, the mounting seat includes a flame retardant part and a mounting part, the mounting part is connected to the flame retardant part, the electric heating element is connected to the mounting part, and is spaced apart and arranged on one side of the flame retardant part.

2. The air conditioner indoor unit according to claim 1, characterized in that: The flame retardant portion includes a flame retardant plate, and the mounting portion includes two mounting plates, and the two mounting plates are spaced apart in the length direction of the flame retardant plate; The two ends of the electric heating element are detachably connected to the two mounting plates respectively.

3. The air conditioner indoor unit according to claim 2, characterized in that: The flame retardant portion and the mounting portion are an integrated structure.

4. The air conditioner indoor unit according to claim 3, characterized in that: The flame retardant part and the mounting part are both made of sheet metal.

5. The air conditioner indoor unit according to claim 2, characterized in that: The width dimension of the flame retardant plate is greater than the width dimension of the electric heating element.

6. The air conditioner indoor unit according to claim 2, characterized in that: The flame retardant plate comprises a plate body, and reinforcing ribs are also arranged on the plate body.

7. The air conditioner indoor unit according to claim 6, characterized in that: A portion of the reinforcing rib passes through a connection between the mounting plate and the plate body and extends to the mounting plate.

8. The air conditioner indoor unit according to any one of claims 2 to 7, characterized in that: One of the flame retardant plate and the housing is provided with a snap-fitting protrusion, and the other of the two is provided with a snap-fitting recess, and the snap-fitting protrusion and the snap-fitting recess are snap-fitted; And / or, the flame retardant plate and the housing are respectively provided with a mounting hole and a connecting hole, and the mounting hole and the connecting hole are detachably connected via a connecting piece.

9. The air conditioner indoor unit according to any one of claims 2 to 7, characterized in that: One end of the electric heating element is plugged into one of the mounting plates, and the other end of the electric heating element is detachably connected to the other mounting plate via a connecting piece.

10. The air conditioner indoor unit according to any one of claims 2 to 7, characterized in that: The air conditioner indoor unit comprises a heat exchanger arranged in the air duct, and the electric heating component is arranged on the air outlet side of the heat exchanger; The electric heating element is arranged in a long strip shape, and the length extension direction of the electric heating element is parallel to the width direction of the heat exchanger.

11. The air conditioner indoor unit according to claim 10, characterized in that: The electric heating element is arranged in a flat plate shape, and the electric heating element includes two plate surfaces opposite to each other in the thickness direction; Wherein, the plate surface of the electric heating element is parallel to the air outlet surface of the heat exchanger; Alternatively, the plate surface of the electric heating element is arranged at an angle to the air outlet surface of the heat exchanger.

12. A HVAC system, characterized in that: It comprises an air-conditioning indoor unit as described in any one of claims 1 to 11.

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