CN218949467U

CN218949467U - Air conditioner indoor unit and marine air conditioning system

Info

Publication number: CN218949467U
Application number: CN202320081497.9U
Authority: CN
Inventors: 雷新建; 黄志豪; 田朋; 朱浩浩; 陈志强; 张翔
Original assignee: Gree Electric Appliances Inc of Zhuhai
Current assignee: Gree Electric Appliances Inc of Zhuhai
Priority date: 2023-01-11
Filing date: 2023-01-11
Publication date: 2023-05-02
Anticipated expiration: 2033-01-11

Abstract

The present disclosure relates to an air conditioning indoor unit and a marine air conditioning system. The indoor unit of the air conditioner comprises: the closed air duct structure (1) is provided with an air return chamber (11), a heat exchange chamber (12) and an air outlet air duct (13); the fan assembly (2) comprises a fan volute (21) and an impeller (22) arranged in the fan volute (21), an air inlet (211) of the fan volute (21) is in sealing connection and communication with the heat exchange chamber (12), an air outlet of the fan volute (21) is in sealing connection and communication with the air outlet air duct (13), and the impeller (22) is configured to drive air in the heat exchange chamber (12) to flow to the air outlet air duct (13) through the fan volute (21); and a heat exchanger (3) disposed between the return air chamber (11) and the heat exchange chamber (12) and configured to exchange heat with gas flowing from the return air chamber (11) to the heat exchange chamber (12).

Description

Air conditioner indoor unit and marine air conditioning system

Technical Field

The disclosure relates to the technical field of air conditioners, in particular to an air conditioner indoor unit and a marine air conditioning system.

Background

The air conditioning system used on the ship can be used for providing air conditioning functions for each cabin in the ship so as to realize the set temperature and humidity requirements. For some cabins used for storing materials or arranging electrical equipment and the like in ships, explosion hazards can exist, and explosion protection safety is needed. The civil air conditioner is only suitable for general environment, carries out refrigeration treatment on common air, and is not suitable for being directly applied to ships as an explosion-proof air conditioner.

Disclosure of Invention

In view of the above, the embodiments of the present disclosure provide an air conditioning indoor unit and a marine air conditioning system, which can provide an air conditioning function while realizing explosion-proof security.

In one aspect of the present disclosure, there is provided an air conditioner indoor unit including:

the closed air duct structure is provided with an air return chamber, a heat exchange chamber and an air outlet air duct;

the fan assembly comprises a fan volute and an impeller arranged in the fan volute, an air inlet of the fan volute is in sealing connection and communication with the heat exchange chamber, an air outlet of the fan volute is in sealing connection and communication with the air outlet air duct, and the impeller is configured to drive air in the heat exchange chamber to flow to the air outlet air duct through the fan volute; and

and a heat exchanger disposed between the return air chamber and the heat exchange chamber and configured to exchange heat with gas flowing from the return air chamber to the heat exchange chamber.

In some embodiments, the air conditioning indoor unit further comprises:

a wind shielding piece which is arranged on the wall surface of the heat exchange chamber adjacent to the fan volute and covers the air inlet of the fan volute,

wherein the wind shield has at least one vent.

In some embodiments, the windshield comprises: the side plate and the coaming are arranged at the edge of the side plate and extend towards the fan volute, the coaming is fixedly connected with the wall surface of the heat exchange chamber, which is adjacent to the fan volute, and the side plate and the coaming form a concave cavity.

In some embodiments, the at least one vent comprises: a plurality of first through holes in the coaming and/or a plurality of second through holes in the side plate.

In some embodiments, the side panels are polygonal and the shroud comprises a plurality of side panel segments connected to each side of the side panels, adjacent side panel segments corresponding to adjacent sides of the side panels being interconnected.

In some embodiments, the cross-sectional shape of the vent is circular, elliptical, or polygonal.

In some embodiments, the closed air duct structure includes a partition plate having a plurality of folds, and the plurality of folds are respectively and fixedly connected to a plurality of sides of the heat exchanger, so that a closed heat exchange chamber is formed between the partition plate and the heat exchanger.

In some embodiments, the heat exchanger comprises a straight plate type fin heat exchanger, wherein an air inlet surface and an air outlet surface of the straight plate type fin heat exchanger are parallel to a wall surface of the heat exchange chamber adjacent to the fan volute.

In some embodiments, the air conditioning indoor unit further comprises:

the compressor is communicated with the heat exchanger through a pipeline;

the motor is positioned at one side of the fan assembly far away from the heat exchanger, and an output shaft of the motor is connected with the impeller to drive the impeller to rotate; and

the electric control box is used for placing an air conditioner electric control device;

the compressor, the motor and the electric cabinet are all located outside the airtight air duct structure.

In some embodiments, the motor is located between the compressor and the fan assembly, and the electric cabinet is located on the upper side of the fan volute and on the side of the air outlet duct.

In some embodiments, the enclosed tunnel structure has a water pan located on the underside of the heat exchanger.

In some embodiments, the air conditioner indoor unit further comprises a body frame, the closed air duct structure is disposed on the body frame, and the closed air duct structure comprises:

the first panel is opposite to the water receiving disc, and an air outlet of the air outlet duct is arranged on the first panel;

the second panel is connected with the first panel and the water receiving disc on one group of opposite sides of the second panel respectively;

a third panel and a fourth panel respectively connected with the other group of opposite sides of the second panel,

wherein at least a portion of the first panel, the second panel, the water tray, the third panel, and at least a portion of the fourth panel enclose the return air chamber.

In some embodiments, the return air compartment has a return air inlet disposed on the first panel or the second panel.

In some embodiments, the air conditioner indoor unit further comprises a body frame, the body frame is provided with a bottom plate and a fifth panel opposite to the bottom plate, the closed air duct structure, the compressor and the motor are all installed on the upper surface of the bottom plate, and the electric cabinet is installed on the lower side of the fifth panel.

In one aspect of the present disclosure, there is provided a marine air conditioning system including the aforementioned air conditioning indoor unit.

Therefore, according to the embodiment of the disclosure, the airtight air duct structure is arranged, and the heat exchange chamber and the air outlet air duct of the airtight air duct structure are respectively in sealing connection and communication with the air inlet and the air outlet of the fan volute of the fan assembly, so that air flow driven by the fan assembly and subjected to heat exchange through the airtight air duct structure is prevented from leaking out of the airtight air duct structure, the air conditioning function is realized, the risk of explosion caused by leaked air flow is reduced, and explosion-proof safety is realized.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the disclosure and together with the description, serve to explain the principles of the disclosure.

The disclosure may be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings in which:

FIG. 1 is a schematic diagram of some embodiments of an air conditioning indoor unit according to the present disclosure;

fig. 2 and 3 are schematic views illustrating an internal structure of an indoor unit of an air conditioner according to an embodiment of the present disclosure at different viewing angles, respectively;

FIG. 4 is a partial cross-sectional view of the location of the air inlet of the blower scroll of FIG. 3;

FIG. 5 is a schematic diagram of an embodiment of an air conditioning indoor unit according to the present disclosure;

FIG. 6 is a schematic view of an air conditioner indoor unit according to an embodiment of the present disclosure with a heat exchanger removed;

FIG. 7 is a schematic view of the mounting structure of a fan assembly, an air outlet duct, and a motor in accordance with an embodiment of the disclosed air conditioning indoor unit;

fig. 8 and 9 are schematic views of external structures of an indoor unit of an air conditioner according to an embodiment of the present disclosure at different viewing angles, respectively;

fig. 10 is a schematic view of an external structure of other embodiments of an air conditioner indoor unit according to the present disclosure

Fig. 11 and 12 are schematic structural views of a wind shielding member in some embodiments of an indoor unit of an air conditioner according to the present disclosure, respectively.

It should be understood that the dimensions of the various elements shown in the figures are not drawn to actual scale. Further, the same or similar reference numerals denote the same or similar members.

Detailed Description

Various exemplary embodiments of the present disclosure will now be described in detail with reference to the accompanying drawings. The description of the exemplary embodiments is merely illustrative, and is in no way intended to limit the disclosure, its application, or uses. The present disclosure may be embodied in many different forms and is not limited to the embodiments described herein. These embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art. It should be noted that: the relative arrangement of parts and steps, the composition of materials, numerical expressions and numerical values set forth in these embodiments should be construed as exemplary only and not limiting unless otherwise specifically stated.

The terms "first," "second," and the like, as used in this disclosure, do not denote any order, quantity, or importance, but rather are used to distinguish one element from another. The word "comprising" or "comprises" and the like means that elements preceding the word encompass the elements recited after the word, and not exclude the possibility of also encompassing other elements. "upper", "lower", "left", "right", etc. are used merely to indicate relative positional relationships, which may also be changed when the absolute position of the object to be described is changed.

In this disclosure, when a particular device is described as being located between a first device and a second device, there may or may not be an intervening device between the particular device and either the first device or the second device. When it is described that a particular device is connected to other devices, the particular device may be directly connected to the other devices without intervening devices, or may be directly connected to the other devices without intervening devices.

All terms (including technical or scientific terms) used in this disclosure have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs, unless specifically defined otherwise. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

Techniques, methods, and apparatus known to one of ordinary skill in the relevant art may not be discussed in detail, but are intended to be part of the specification where appropriate.

Fig. 1 is a schematic structural view of some embodiments of an air conditioning indoor unit according to the present disclosure. Referring to the internal and external structures of the air conditioning indoor unit shown in fig. 1 and 2 to 12, respectively, the embodiment of the present disclosure provides an air conditioning indoor unit. The indoor unit of the air conditioner comprises: the air conditioner comprises a closed air duct structure 1, a fan assembly 2 and a heat exchanger 3. The closed air duct structure 1 is provided with an air return chamber 11, a heat exchange chamber 12 and an air outlet air duct 13. The return air chamber 11 may have a return air inlet 111 for receiving return air from the active area of the air conditioning indoor unit. The heat exchanger 3 is arranged between the return air chamber 11 and the heat exchange chamber 12 and is configured to exchange heat with the gas flowing from the return air chamber 11 to the heat exchange chamber 12.

The fan assembly 2 comprises a fan volute 21 and an impeller 22 arranged within said fan volute 21. The air inlet 211 of the fan volute 21 is in sealing connection and communication with the heat exchange chamber 12, and the air outlet of the fan volute 21 is in sealing connection and communication with the air outlet duct 13. The impeller 22 is configured to drive the gas in the heat exchange chamber 12 to flow to the air outlet duct 13 through the fan volute 21.

The embodiment sets up airtight wind channel structure to make airtight wind channel structure's heat transfer room and air-out wind channel respectively with fan assembly's fan spiral case air intake and air exit sealing connection and intercommunication, with avoid receiving fan assembly drive and flow through airtight wind channel structure and carry out the air current of heat exchange leak outside the airtight wind channel structure, thereby reduce the risk of causing the explosion because of the air current of leaking when realizing the air conditioning function, realized explosion-proof safety.

The impeller 22 of the fan assembly 2 is capable of sucking the air flow in the heat exchange chamber 12 from the air inlet 211 thereof, and in order to avoid the air flow of the air return chamber 11 from intensively flowing to the air inlet 211 and causing the heat exchange efficiency of the heat exchanger 3 to be reduced, referring to fig. 5 and 6, in some embodiments, the air conditioner indoor unit further includes a wind shielding member 4. The wind shielding member 4 is arranged on the wall surface 121 of the heat exchange chamber 12 adjacent to the fan volute 21 and covers the air inlet of the fan volute 21. The wind shielding member 4 has at least one vent hole. The air flow thus entering the heat exchange chamber 12 no longer enters the air inlet 211 directly, but instead passes through at least one ventilation opening in the wind deflector 4 and divergently enters the air inlet 211. The vent holes can play a role in wind shielding and depressurization, so that the airflow passes through the heat exchanger 3 more uniformly, and the heat exchange efficiency of the heat exchanger 3 is improved.

Referring to fig. 5, 6, 11 and 12, in some embodiments, the windshield 4 includes side panels 41 and a shroud 42. A shroud 42 is provided at the edge of the side plate 41 and extends towards the fan volute 21. The shroud 42 is fixedly connected with the wall 121 of the heat exchange chamber 12 adjacent to the fan volute 21, and the side plate 41 and the shroud 42 form a concave cavity. As can be seen from fig. 4, the concave wind shielding member 4 is fastened to the wall surface 121 and covers the air inlet 211.

Referring to fig. 11 and 12, in some embodiments, the at least one vent includes: a plurality of first through holes 421 located in the shroud 42, and/or a plurality of second through holes 411 located in the side plate 41. By providing a plurality of through holes in the shroud 42 and/or the side plate 41, the airflow can be more dispersed from the outside of the weather shield 4 into the inside of the weather shield 4. Through the arrangement of the through holes with different numbers, different sizes and different distribution positions, the adjustment of the air outlet state (such as air quantity, air pressure and the like) of the heat exchanger can be realized. Accordingly, different windshields 4 may be replaced as needed.

In fig. 11 and 12, the side plate 41 has a polygonal shape, the coaming 42 includes a plurality of side plate segments connected to each side of the side plate 41, and adjacent side plate segments corresponding to adjacent sides of the side plate 41 are connected to each other. The plurality of second through holes 411 are arranged in at least one direction of the surface of the side plate 41, for example, in an array. Each side plate section of the coaming 42 may be provided with a plurality of first through holes 421, and the plurality of first through holes 421 may be arranged at intervals along a connecting line of the side plate and the coaming.

In some embodiments, the cross-sectional shape of the vent is circular, elliptical, or polygonal. The cross section here refers to a section perpendicular to the thickness direction of the side plate or the coaming where the vent hole is located. For example, in fig. 11, the cross-sectional shape of the vent is circular; in fig. 12, the cross-sectional shape of the vent is diamond-shaped. In other embodiments, the cross-sectional shape of the vent may also be oval, triangular, hexagonal, etc.

Referring to fig. 6, in some embodiments, the enclosed tunnel structure 1 includes a partition 14 having a plurality of folds 141. The folded edges 141 are fixedly connected with a plurality of sides of the heat exchanger 3 respectively, so that a closed heat exchange chamber 12 is formed between the partition 14 and the heat exchanger 3. For convenient assembly, a partition plate 14 of a sheet metal part can be adopted, and the partition plate is hermetically and fixedly connected with the side surface of the heat exchanger 3 through folded edges on the upper side and the left side and the right side of the partition plate so as to prevent air flow in the heat exchange chamber 12 from leaking outwards from the side plates. The wind shielding member 4 may be fixedly connected to the wall surface 121 of the bulkhead 14 by a connecting member such as a bolt.

In some embodiments, the heat exchanger 3 comprises a straight plate type fin heat exchanger with an inlet face 31 and an outlet face parallel to a wall 121 of the heat exchange chamber 12 adjacent to the fan volute 21. Through this kind of overall arrangement structure, can make heat exchanger and heat exchange chamber occupy less space in the thickness direction of straight plate type fin heat exchanger to make airtight wind channel structure be higher at the indoor set of air conditioner inside space utilization, can provide bigger space of placing for vibration cylinder bodies such as compressor when guaranteeing self working property.

Referring to fig. 1 to 5, in some embodiments, the closed duct structure 1 has a water pan 15 located at the lower side of the heat exchanger 3. The water receiving tray 15 can receive condensed water generated during heat exchange of the heat exchanger 3, and the condensed water can be discharged through a water outlet of the water receiving tray 15.

Referring to fig. 1, in some embodiments, the air conditioning indoor unit further includes a body frame 8. The closed air duct structure 1 is arranged on the machine body frame 8. The closed duct structure 1 may include: a first panel 161, a second panel 162, a third panel 163, and a fourth panel 164. The first panel 161 may be provided on the upper side of the heat exchanger 3 as a top plate, opposite to the water receiving tray 15. The air outlet 131 of the air outlet duct 13 may be disposed on the first panel 161. A set of opposite sides of the second panel 162 are respectively connected to the first panel 161 and the drip tray 15.

Referring to fig. 1-5, the return air inlet 111 of the return air compartment 11 may also be provided on the first panel 161. This facilitates the situation where both the return air side and the outlet air side are located outside the first panel 161. Referring to fig. 10, the return air inlet 111 of the return air compartment 11 may also be provided on the second panel 162. This facilitates the case where the return air side and the outlet air side are provided outside the first panel 161 and the second panel 162, respectively.

Referring to fig. 8 and 9, a third panel 163 and a fourth panel 164 are respectively connected to the other set of opposite sides of the second panel 162. The first panel 161, the second panel 162, the water tray 15, at least a portion of the third panel 163, and at least a portion of the fourth panel 164 enclose the return air compartment 11.

In some embodiments, the third panel 163 and the fourth panel 164 are opposite and connected to the first panel 161, the drip tray 15, and the second panel 162, respectively, to form a closed structure. In other embodiments, the third panel 163 and the fourth panel 164 are connected to the first panel 161, the water tray 15 and the second panel 162 through a part of the surfaces, so as to form a closed structure, and the other part of the surfaces can form a space for accommodating other components of the indoor unit, so as to save the number of components.

Referring to fig. 1 to 7, in some embodiments, the air conditioner indoor unit may further include: a compressor 5, a motor 6 and an electric cabinet 7. The compressor 5 is communicated with the heat exchanger 3 through a pipeline to form a refrigerant circulation loop, so that the refrigerating or heating function is realized. A motor 6 is located on a side of the fan assembly 2 remote from the heat exchanger 3, and an output shaft of the motor 6 is connected to the impeller 22 to drive the impeller 22 to rotate. The electric cabinet 7 is used for placing air conditioning electric control devices, which here can be used for controlling the compressor 5, the motor 6 or other devices.

The compressor 5, the motor 6 and the electric cabinet 7 are all located outside the closed air duct structure 1. The air duct of the air conditioner indoor unit can be separated from electric elements such as a motor, an electric cabinet and a compressor, and flammable and explosive gas is prevented from contacting with the electric elements, so that explosion hidden danger is eliminated.

Referring to fig. 1, in order to make the indoor unit more compact in internal structure and smaller in overall size, in some embodiments, the motor 6 is located between the compressor 5 and the fan assembly 2, and the electric cabinet 7 is located on the upper side of the fan volute 21 and on the side of the air outlet duct 13. As can be seen from fig. 2, the fan volute 21, the air outlet duct 13 and the heat exchange chamber 12 together define a concave area, and the electric cabinet 7 is arranged in this area, so that the thicknesses of the electric cabinet 7 and the air outlet duct 13 in the thickness direction of the heat exchanger overlap, which is beneficial to further reducing the size of the indoor unit in the direction.

In fig. 3 and 10, the body frame 8 may have a bottom plate 81 and a fifth panel 82 opposite to the bottom plate 81. The airtight air duct structure 1, the compressor 5 and the motor 6 are all installed on the upper surface of the bottom plate 81, and the electric cabinet 7 is installed on the lower side of the fifth panel 82, so that an indoor unit structure with smaller size and regular shape can be formed, and the indoor unit structure is convenient to arrange in various scenes.

The embodiments of the air conditioning indoor unit disclosed in the disclosure can be applied to various air conditioning systems with explosion-proof requirements, such as air conditioning systems for ships. Accordingly, in one aspect of the present disclosure, there is also provided a marine air conditioning system including the air conditioning indoor unit of any of the foregoing embodiments.

The operation of one embodiment of the indoor unit of the air conditioner will be described with reference to fig. 1 to 10.

When the indoor unit of the air conditioner works, external air (such as return air in an action area of the indoor unit of the air conditioner can be inflammable and explosive gas) enters the return air chamber through the return air inlet, and the air in the return air chamber flows to the fan volute under the drive of the impeller in the fan volute, so that the air flows into the heat exchange chamber through the heat exchanger, enters the fan volute through the vent hole on the wind shielding piece, and flows outwards from the air outlet through the air outlet channel under the action of the impeller. The air can not leak to other parts of the indoor unit in the process from the return air inlet to the air outlet, so that the air can not contact with a compressor, a motor and an electric cabinet in the indoor unit, and further the explosion risk is eliminated.

Thus, various embodiments of the present disclosure have been described in detail. In order to avoid obscuring the concepts of the present disclosure, some details known in the art are not described. How to implement the solutions disclosed herein will be fully apparent to those skilled in the art from the above description.

Although some specific embodiments of the present disclosure have been described in detail by way of example, it should be understood by those skilled in the art that the above examples are for illustration only and are not intended to limit the scope of the present disclosure. It will be understood by those skilled in the art that the foregoing embodiments may be modified and equivalents substituted for elements thereof without departing from the scope and spirit of the disclosure. The scope of the present disclosure is defined by the appended claims.

Claims

1. An air conditioning indoor unit, comprising:

the closed air duct structure (1) is provided with an air return chamber (11), a heat exchange chamber (12) and an air outlet air duct (13);

the fan assembly (2) comprises a fan volute (21) and an impeller (22) arranged in the fan volute (21), an air inlet (211) of the fan volute (21) is in sealing connection and communication with the heat exchange chamber (12), an air outlet of the fan volute (21) is in sealing connection and communication with the air outlet air duct (13), and the impeller (22) is configured to drive air in the heat exchange chamber (12) to flow to the air outlet air duct (13) through the fan volute (21); and

and a heat exchanger (3) disposed between the return air chamber (11) and the heat exchange chamber (12) and configured to exchange heat with gas flowing from the return air chamber (11) to the heat exchange chamber (12).

2. The indoor unit of claim 1, further comprising:

a wind shielding piece (4) which is arranged on the wall surface (121) of the heat exchange chamber (12) adjacent to the fan volute (21) and covers the air inlet of the fan volute (21),

wherein the wind shield (4) has at least one ventilation opening.

3. An air conditioning indoor unit according to claim 2, characterized in that the wind shield (4) comprises: the side plate (41) and the coaming (42) are arranged at the edge of the side plate (41) and extend towards the fan volute (21), the coaming (42) is fixedly connected with the heat exchange chamber (12) adjacent to the wall surface (121) of the fan volute (21), and the side plate (41) and the coaming (42) form a concave cavity.

4. An air conditioning indoor unit according to claim 3, wherein the at least one vent comprises: a plurality of first through holes (421) located in the coaming (42), and/or a plurality of second through holes (411) located in the side plate (41).

5. An indoor unit for air conditioning according to claim 3, wherein the side plate (41) is polygonal, the shroud (42) comprises a plurality of side plate segments connected to respective sides of the side plate (41), and adjacent side plate segments corresponding to adjacent sides of the side plate (41) are connected to each other.

6. An air conditioning indoor unit according to claim 2, wherein the cross-sectional shape of the vent is circular, oval or polygonal.

7. An indoor unit for air conditioning according to claim 1, wherein the closed duct structure (1) comprises a partition (14) having a plurality of folds (141), the folds (141) being fixedly connected to a plurality of sides of the heat exchanger (3), respectively, so that a closed heat exchange chamber (12) is formed between the partition (14) and the heat exchanger (3).

8. An indoor unit for air conditioning according to claim 1, wherein the heat exchanger (3) comprises a straight-plate type fin heat exchanger, the air inlet face (31) and the air outlet face of which are both parallel to the wall face (121) of the heat exchange chamber (12) adjacent to the fan volute (21).

9. The indoor unit of claim 1, further comprising:

a compressor (5) which is communicated with the heat exchanger (3) through a pipeline;

the motor (6) is positioned on one side of the fan assembly (2) away from the heat exchanger (3), and an output shaft of the motor (6) is connected with the impeller (22) so as to drive the impeller (22) to rotate; and

the electric control box (7) is used for placing an air conditioner electric control device;

the compressor (5), the motor (6) and the electric cabinet (7) are all located outside the airtight air duct structure (1).

10. An indoor unit for an air conditioner according to claim 9, characterized in that the motor (6) is located between the compressor (5) and the fan assembly (2), the electric cabinet (7) is located on the upper side of the fan volute (21) and on the side of the air outlet duct (13).

11. An air conditioning indoor unit according to claim 1, characterized in that the closed duct structure (1) has a water pan (15) located on the underside of the heat exchanger (3).

12. The indoor unit of claim 11, further comprising a machine body frame (8), wherein the closed duct structure (1) is disposed on the machine body frame (8), and wherein the closed duct structure (1) comprises:

the first panel (161) is opposite to the water receiving disc (15), and an air outlet (131) of the air outlet duct (13) is arranged on the first panel (161);

a second panel (162), a set of opposite sides of the second panel (162) being connected to the first panel (161) and the drip tray (15), respectively;

a third panel (163) and a fourth panel (164), each connected to the other set of opposite sides of the second panel (162),

wherein at least part of the first panel (161), the second panel (162), the water pan (15), the third panel (163) and at least part of the fourth panel (164) enclose the return air compartment (11).

13. The indoor unit of claim 12, wherein the return air chamber (11) has a return air port (111), the return air port (111) being provided on the first panel (161) or the second panel (162).

14. The indoor unit of claim 9, further comprising a body frame (8), wherein the body frame (8) has a bottom plate (81) and a fifth panel (82) opposite to the bottom plate (81), the closed duct structure (1), the compressor (5) and the motor (6) are all installed on an upper surface of the bottom plate (81), and the electric cabinet (7) is installed on a lower side of the fifth panel (82).

15. A marine air conditioning system, comprising:

an air conditioning indoor unit according to any one of claims 1 to 14.