Duct type air conditioner

Abstract

The utility model discloses a duct type air conditioner, and belongs to the technical field of air conditioners. The ducted type air conditioner comprises a shell, an air inlet, an air supply outlet, an air outlet, a fan, a fan and an air supply pipe, and the air inlet comprises an indoor return air inlet and an outdoor fresh air inlet; the first heat exchanger is arranged in the shell corresponding to the air supply outlet; the second heat exchanger corresponds to the outdoor fresh air opening and is located on the windward side of the first heat exchanger; the duct type air conditioner further comprises an indoor expansion valve and an electromagnetic valve. In a refrigerant system of the duct type air conditioner, a liquid side stop valve, a second heat exchanger, an indoor expansion valve, a first heat exchanger and a gas side stop valve are sequentially connected in series; the second heat exchanger and the indoor expansion valve form a first branch; the electromagnetic valve is connected with the first branch in parallel; the duct type air conditioner enables indoor air to flow to the air supply outlet through the indoor air return opening and the first heat exchanger and enables outdoor fresh air to flow to the air supply outlet through the outdoor fresh air opening, the second heat exchanger and the first heat exchanger. The duct type air conditioner has a fresh air function and can avoid condensation.

Description

Technical Field

[0001] The present application relates to the technical field of air conditioning, and in particular to a duct air conditioner. Background Art

[0002] At present, most duct air conditioners do not have the function of introducing fresh air. The few duct air conditioners with fresh air function can be roughly divided into two forms: one is to directly open a fresh air inlet on the outer casing of the duct air conditioner to connect with the outdoor air; the other is to install a fresh air module on the duct air conditioner.

[0003] These ducted air conditioners with the function of introducing fresh air all have the problem of condensation. Take winter as an example, when the outdoor temperature is below -10℃ but the indoor temperature is high, users need to introduce fresh air. At this time, condensation will occur when the fresh air comes into contact with the high temperature and high humidity indoor air. Utility Model Content

[0004] The present application provides a duct air conditioner which has a fresh air function and can avoid the occurrence of condensation.

[0005] One aspect of the present application. A duct air conditioner comprises: a housing, on which an air inlet and an air supply port are provided, the air inlet comprising an indoor return air port and an outdoor fresh air port; a first heat exchanger, arranged in the housing corresponding to the air supply port; a second heat exchanger, arranged corresponding to the outdoor fresh air port, the second heat exchanger being located on the windward side of the first heat exchanger, the second heat exchanger being used as an evaporator in cooling and as a condenser in heating;

[0006] The duct unit allows indoor air to flow to the supply air outlet through the indoor return air outlet and the first heat exchanger, and allows outdoor fresh air to flow to the supply air outlet through the outdoor fresh air outlet, the second heat exchanger and the first heat exchanger.

[0007] In another aspect of the present application, a duct machine includes: a housing, on which an air inlet and an air supply port are provided, the air inlet including an indoor return air port and an outdoor fresh air port; a first heat exchanger, arranged in the housing corresponding to the air supply port; a second heat exchanger, arranged corresponding to the outdoor fresh air port, the second heat exchanger being located on the windward side of the first heat exchanger;

[0008] The duct unit also includes an indoor expansion valve and a solenoid valve;

[0009] In the refrigerant system of the duct unit, the liquid-side stop valve, the second heat exchanger, the indoor expansion valve, the first heat exchanger, and the gas-side stop valve are connected in series in sequence; the second heat exchanger and the indoor expansion valve form a first branch, and the solenoid valve is connected in parallel with the first branch;

[0010] The duct unit allows indoor air to flow to the supply air outlet through the indoor return air outlet and the first heat exchanger, and allows outdoor fresh air to flow to the supply air outlet through the outdoor fresh air outlet, the second heat exchanger and the first heat exchanger.

[0011] In some embodiments, part of the space in the housing near the air inlet is the air inlet space;

[0012] The air duct machine also includes: a fan, which is arranged between the air inlet space and the first heat exchanger and is used to drive the flow of indoor air and outdoor fresh air;

[0013] An air baffle is arranged in the shell, which divides the air inlet space into an indoor air inlet space connected to the indoor return air outlet, and a fresh air inlet space connected to the outdoor fresh air outlet; the second heat exchanger is arranged in the fresh air inlet space.

[0014] In some embodiments, there is a gap between the wind baffle and the fan to form an air mixing space.

[0015] In some embodiments, part of the space in the housing near the air inlet is the air inlet space; the first heat exchanger is located between the air inlet space and the air outlet;

[0016] An air baffle is provided in the shell, which divides the air inlet space into an indoor air inlet space connected to the indoor return air outlet and a fresh air inlet space connected to the outdoor fresh air outlet;

[0017] The air duct machine also includes: a first fan, arranged in the indoor air inlet space, for driving the indoor air to blow toward the first heat exchanger; a second fan, arranged in the fresh air inlet space, for driving the outdoor fresh air to blow toward the first heat exchanger.

[0018] In some embodiments, there is a gap between the wind baffle and the first heat exchanger to form an air mixing space.

[0019] In some embodiments, with reference to the flow path of outdoor fresh air, the second fan is located downstream of the second heat exchanger.

[0020] In some embodiments, an air outlet flange is provided at the indoor return air outlet, and a plurality of knock-off plates are stacked in the air outlet flange along the radial direction.

[0021] In some embodiments, in the refrigerant system, an outdoor expansion valve is connected in series between the outdoor heat exchanger and the liquid-side stop valve; when the duct unit is defrosting, the outdoor expansion valve is in a fully open state, the solenoid valve is in a closed state, the outdoor heat exchanger and the second heat exchanger are used as a condenser, and the first heat exchanger is used as an evaporator;

[0022] The duct unit allows outdoor fresh air to pass through the second heat exchanger and the first heat exchanger in sequence and blow into the room.

[0023] In some embodiments, when the duct air conditioner operates in mixed air mode, the solenoid valve is in a closed state and the indoor expansion valve is in a fully open state, so that the second heat exchanger and the first heat exchanger are both used as evaporators during cooling and as condensers during heating. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 A diagram showing the internal structure of a duct machine according to some embodiments;

[0025] Figure 2 A diagram showing the internal structure of a duct machine according to other embodiments;

[0026] Figure 3 shows a side view of an air vent flange of a duct machine according to some embodiments;

[0027] Figure 4 A diagram showing a refrigerant system of a ducted air conditioner in cooling mode according to some embodiments;

[0028] Figure 5 A diagram showing a refrigerant system of a duct unit in cooling mode according to other embodiments;

[0029] Figure 6 A diagram showing a refrigerant system of a duct unit in heating mode according to some embodiments;

[0030] Figure 7 A diagram showing a refrigerant system of a duct unit in heating mode according to other embodiments;

[0031] Figure 8 A diagram showing air flow of a duct unit in fresh air mode according to some embodiments;

[0032] Fig. 9 A diagram showing air flow of a ducted air conditioner in return air mode according to some embodiments;

[0033] Fig.10 A diagram illustrating air flow of a duct unit in mixed air mode according to some embodiments.

[0034] In the above figures, 10, shell; 11, front side plate; 111, air supply port; 12, rear side plate; 121, indoor return air port; 122, outdoor fresh air port; 13, left side plate; 14, right side plate; 15, air port flange; 151, knock-off plate; 1511, first knock-off plate; 1512, second knock-off plate; 16, wind baffle; 171, indoor air inlet space; 172, fresh air inlet space; 21, first heat exchanger; 22, second heat exchanger; 23, indoor expansion valve; 24, solenoid valve; 30, fan; 31, first fan; 32, second fan; 40, filter; 51, compressor; 52, outdoor heat exchanger; 53, four-way valve; 54, outdoor expansion valve; 55, outdoor fan; 61, liquid side stop valve; 62, gas side stop valve. DETAILED DESCRIPTION

[0035] In order to make the purpose and implementation method of the present application clearer, the exemplary implementation method of the present application will be clearly and completely described below in conjunction with the drawings in the exemplary embodiments of the present application. Obviously, the described exemplary embodiments are only part of the embodiments of the present application, rather than all the embodiments.

[0036] In the description of the present application, it should be understood that the terms "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0037] The terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of this application, unless otherwise specified, "plurality" means two or more.

[0038] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0039] The duct machine in the embodiment of the present application is a type of air conditioner.

[0040] The air conditioner performs the refrigeration cycle of the air conditioner by using a compressor, a condenser, an expansion valve and an evaporator. The refrigeration cycle includes a series of processes involving compression, condensation, expansion and evaporation, and supplies refrigerant to the air that has been conditioned and heat exchanged.

[0041] The compressor compresses the refrigerant gas in a low temperature and low pressure state and discharges the compressed refrigerant gas. The discharged refrigerant gas flows into the condenser. The condenser condenses the compressed refrigerant into a liquid phase, and the heat is released to the surrounding environment through the condensation process.

[0042] The expansion valve expands the high-temperature and high-pressure liquid refrigerant condensed in the condenser into a low-pressure liquid refrigerant. The evaporator evaporates the refrigerant expanded in the expansion valve and returns the refrigerant gas in a low-temperature and low-pressure state to the compressor. The evaporator can achieve a refrigeration effect by utilizing the latent heat of evaporation of the refrigerant to exchange heat with the material to be cooled. In the entire cycle, the air conditioner can adjust the temperature of the indoor space.

[0043] The outdoor unit of the air conditioner refers to a portion of a refrigeration cycle including a compressor and an outdoor heat exchanger, the indoor unit of the air conditioner includes an indoor heat exchanger, and an expansion valve may be provided in the indoor unit or the outdoor unit.

[0044] The indoor heat exchanger and the outdoor heat exchanger function as a condenser or an evaporator. When the indoor heat exchanger functions as a condenser, the air conditioner functions as a heater in a heating mode, and when the indoor heat exchanger functions as an evaporator, the air conditioner functions as a cooler in a cooling mode.

[0045] The duct unit has an indoor unit and an outdoor unit. The indoor unit is used to perform heat exchange with indoor air. For duct units with fresh air function, the indoor unit is also used to perform heat exchange with outdoor fresh air. The outdoor unit is used to perform heat exchange with outdoor air.

[0046] Reference Figure 1 and Figure 2 According to the embodiment of the present application, the indoor unit of the duct air conditioner includes a housing 10 having an indoor return air port 121 and an air supply port 111 .

[0047] The housing 10 may be in a rectangular parallelepiped shape to form the overall appearance of the ducted air conditioner. The housing 10 includes a top plate constituting a top structure, a bottom plate constituting a bottom structure, and four side plates connected between the top plate and the bottom plate. The four side plates are a front side plate 11, a rear side plate 12, a left side plate 13, and a right side plate 14. The side plates may be made of sheet metal.

[0048] The indoor return air vent 121 may be disposed on the rear side plate 12. The air supply vent 111 may be disposed on the front side plate 11. However, the embodiment of the present application is not limited thereto, and the indoor return air vent 121 may also be disposed at the front of the bottom plate. The air supply vent 111 may also be disposed at the rear of the bottom plate.

[0049] The indoor return air port 121 is in communication with the room and is used to collect indoor air into the housing 10 .

[0050] The indoor return air vent 121 may be rectangular and directly connected to the air inlet grille of the indoor ceiling to achieve communication between the indoor return air vent 121 and the indoor air. Alternatively, in other embodiments, the indoor return air vent 121 is connected to an air vent flange 15, and the air vent flange 15 is connected to the indoor air through an air duct.

[0051] The air outlet 111 is connected to the room and is used to release air into the room. The air outlet 111 can be connected to the indoor air through an air duct.

[0052] The housing 10 is also provided with an outdoor fresh air outlet 122 for communicating with outdoor air so as to collect outdoor air into the housing 10 .

[0053] The outdoor fresh air inlet 122 and the indoor return air inlet 121 can be arranged on the same wall of the housing 10. Exemplarily, the outdoor fresh air inlet 122 and the indoor return air inlet 121 are arranged left and right and are arranged on the rear side plate 12. This is equivalent to dividing the indoor return air inlet of the duct air conditioner that originally had no fresh air function into two, one of which is still used as the indoor return air inlet 121, and the other is used as the outdoor fresh air inlet 122.

[0054] In other embodiments, the outdoor fresh air inlet 122 and the indoor return air inlet 121 may be arranged on different walls of the housing 10. Exemplarily, the outdoor fresh air inlet 122 is arranged on the rear side plate 12, and the indoor return air inlet 121 is arranged at the rear of the bottom plate.

[0055] The outdoor fresh air outlet 122 can be connected to the air outlet flange 15, and the air outlet flange 15 is connected to the outdoor air through the air duct.

[0056] For the convenience of description, the indoor return air outlet 121 and the outdoor fresh air outlet 122 are collectively referred to as air inlets hereinafter.

[0057] The air duct machine may include a first heat exchanger 21. The first heat exchanger 21 may be disposed inside the housing 10 and may be disposed on an air movement path from the air inlet to the air outlet 111. Exemplarily, the first heat exchanger 21 may be disposed closer to the air outlet 111 in the housing 10. The first heat exchanger 21 is used to absorb heat from the air introduced into the air inlet or to transfer heat to the air.

[0058] The duct machine may include a fan 30. The fan 30 is disposed inside the housing 10 and is used to drive air flow so that indoor air flows from the indoor return air port 121 to the air supply port 111 and outdoor fresh air flows from the outdoor fresh air port 122 to the air supply port 111.

[0059] The fan 30 may be disposed on the windward side of the first heat exchanger 21, that is, between the air inlet and the first heat exchanger 21. The fan 30 may be a centrifugal fan, which has the characteristics of large air volume and small size.

[0060] When the temperature difference between indoor and outdoor is large, condensation may occur when outdoor fresh air contacts indoor air after being introduced by the fan 30. To solve this technical problem, a second heat exchanger 22 is introduced in the embodiment of the present application.

[0061] The second heat exchanger 22 is disposed in the housing 10 corresponding to the outdoor fresh air outlet 122 for exchanging heat with the outdoor fresh air. Specifically, the second heat exchanger 22 is located between the outdoor fresh air outlet 122 and the fan 30.

[0062] The outdoor fresh air introduced from the outdoor fresh air outlet 122 will pass through the second heat exchanger 11 and the first heat exchanger 12 when flowing in the shell 10; the indoor air introduced from the indoor return air outlet 121 will not pass through the second heat exchanger 11 when flowing in the shell 10, but only pass through the first heat exchanger 12.

[0063] The second heat exchanger 22 can cool down the outdoor fresh air when used as an evaporator, and can heat up the outdoor fresh air when used as a condenser.

[0064] Therefore, in the embodiment of the present application, as soon as the outdoor fresh air enters the shell 10 from the outdoor fresh air inlet 122, it is cooled / heated by the second heat exchanger 22, thereby reducing the temperature difference between the indoor air and the outdoor fresh air and avoiding condensation problems.

[0065] Compared with the existing duct air conditioner models without fresh air function, in the embodiment provided in the present application, the distance between the fan 30 and the air inlet is increased to facilitate the installation of the second heat exchanger 22 in the space.

[0066] According to an embodiment of the present application, a portion of the space near the air inlet in the housing 10 is referred to as an air inlet space. An air baffle 16 is provided in the housing 10. The air baffle 16 divides the air inlet space into an indoor air inlet space 171 and a fresh air inlet space 172. The indoor air inlet space 171 corresponds to the indoor return air inlet 121 and is connected to the indoor return air inlet 121; the fresh air inlet space 172 corresponds to the outdoor fresh air inlet 122 and is connected to the outdoor fresh air inlet 122. The second heat exchanger 22 is disposed in the fresh air inlet space 172.

[0067] Due to the blocking effect of the wind baffle 16 , the indoor air enters the housing 10 from the indoor return air port 121 and flows toward the fan 30 , but does not flow toward the second heat exchanger 22 .

[0068] In some embodiments, the duct unit includes a filter 40. The filter 40 is disposed between the outdoor fresh air inlet 122 and the second heat exchanger 22 to filter the outdoor fresh air.

[0069] In some embodiments, the air baffle 16 is located in the space between the air inlet and the fan 30. Indoor air flows to the fan 30 through the indoor air inlet space 171; outdoor fresh air flows to the fan 30 through the fresh air inlet space 172.

[0070] There is a gap between the wind baffle 16 and the fan 30 to form a mixed air space. Therefore, when the duct air conditioner operates in the mixed air mode, that is, the indoor air and the outdoor fresh air flow into the housing 10 at the same time, the indoor air and the outdoor fresh air are mixed on the windward side of the fan 30, thereby further reducing the temperature difference between the two and avoiding the generation of condensation at the fan 30.

[0071] The fan 30 can be a structure in which one motor drives two or more fans. This structure is applicable to the prior art and will not be described in detail here.

[0072] The indoor air and the outdoor fresh air are driven by the same fan 30 .

[0073] In some embodiments, specific reference is made to Figure 2 The fan 30 includes a first fan 31 and a second fan 32. The first fan 31 is arranged in the indoor air intake space 171, and the second fan 32 is arranged in the fresh air intake space 172.

[0074] The indoor air is driven by the first fan 31, and the outdoor air is driven by the second fan 32. Driven by the first fan 31, the indoor air flows to the first heat exchanger 21 through the indoor air inlet space 171; driven by the second fan 32, the outdoor fresh air flows to the first heat exchanger 21 through the fresh air inlet space 172.

[0075] The second heat exchanger 22 is located upstream of the second fan 32 , so that the outdoor fresh air is firstly temperature-controlled by the second heat exchanger 22 and then flows to the second fan 32 , thereby avoiding condensation on the second fan 32 .

[0076] According to an embodiment of the present application, there is a gap from the air inlet space to the windward side of the first heat exchanger 21 to form an air mixing space, so that indoor air and outdoor fresh air can be mixed at the gap, thereby ensuring the uniformity of heat exchange at the first heat exchanger 21.

[0077] In some embodiments, the size of the air inlet area at the indoor return air outlet 121 can be adjusted.

[0078] The outdoor fresh air outlet 122 needs to be connected to the outdoors through an air duct, which will result in the static pressure on the fresh air side being greater than or equal to the static pressure on the indoor side during actual off-site installation. In order to ensure that fresh air can be normally introduced even if the static pressure on the fresh air side is much greater than the static pressure on the indoor side, the air inlet area of ​​the indoor return air outlet 121 is set to be adjustable, so that the appropriate return air outlet size can be selected according to the actual off-site installation situation.

[0079] According to the embodiments of the present application, referring to Figure 3 A plurality of radially stacked knock-off plates 151 are provided in the air outlet flange 15 . By knocking off the knock-off plates 151 from the inner circle to the outer circle, the air inlet area of ​​the indoor return air outlet 121 can be changed.

[0080] Exemplarily, the knock-off plate 151 has two layers, namely a first knock-off plate 1511 located at an inner layer and a second knock-off plate 1512 located at an outer layer.

[0081] When the two layers of knock-off plates 151 are not knocked off, the air inlet area of ​​the indoor return air outlet 121 is the smallest; when the first layer of knock-off plates 1511 is knocked off, the air inlet area of ​​the indoor return air outlet 121 is at an intermediate value; after the two layers of knock-off plates 151 are knocked off, the air inlet area of ​​the indoor return air outlet 121 is the largest.

[0082] In other embodiments, the air inlet area of ​​the indoor return air outlet 121 may be adjusted by adjusting the angle of the air valve at the indoor return air outlet 121 .

[0083] Corresponding to the indoor unit and the outdoor unit of the duct unit, the refrigerant system of the duct unit includes an outdoor side part and an indoor side part.

[0084] Reference Figures 4 to 7 In the refrigerant system of the duct unit, the indoor side part includes: a first heat exchanger 21, which performs heat exchange between indoor air and refrigerant, and outdoor fresh air and refrigerant; a second heat exchanger 22, which performs heat exchange between outdoor fresh air and refrigerant; an indoor expansion valve 23, which decompresses the refrigerant, or is used to control the refrigerant flow in the second heat exchanger 22; and a solenoid valve 24, which is used to control the flow path.

[0085] The refrigerant system further includes a liquid pipe and a gas pipe connected between the indoor side portion and the outdoor side portion.

[0086] The indoor side part is connected to the liquid pipe through the liquid side stop valve 61 and is connected to the gas pipe through the gas side stop valve 62.

[0087] The liquid stop valve 61, the second heat exchanger 22, the indoor expansion valve 23, the first heat exchanger 21, and the gas stop valve 62 are connected in series in sequence. The second heat exchanger 22 and the indoor expansion valve 23 form a first branch, and the solenoid valve 24 is connected in parallel with the first branch.

[0088] In the refrigerant system of the duct unit, the outdoor part includes: a compressor 51 for compressing the refrigerant; an outdoor heat exchanger 52 for performing heat exchange between the outdoor air and the refrigerant; a four-way valve 53 for selectively directing the refrigerant compressed by the compressor 51 to the outdoor heat exchanger 52 or the indoor part according to the heating mode or the cooling mode; an outdoor expansion valve 54 for decompressing the refrigerant; and an outdoor fan 55 for driving the outdoor air through the outdoor heat exchanger 52.

[0089] When the compressor 51 is powered on, the rotation of the motor therein compresses the low-pressure gaseous refrigerant to a high pressure.

[0090] The four-way valve 53 guides the refrigerant compressed in the compressor 51 to the outdoor heat exchanger 52 in the cooling mode, and guides the refrigerant compressed in the compressor 51 to the indoor side portion in the heating mode.

[0091] The outdoor heat exchanger 52 has the same structure as the first heat exchanger 21 and the second heat exchanger 22, and can adopt a finned heat exchanger. The finned heat exchanger may include: a refrigerant tube, in which the refrigerant flows; and fins, which are sleeved on the refrigerant tube to increase the surface area of ​​the refrigerant tube to improve the heat exchange efficiency between the refrigerant and the air.

[0092] The outdoor expansion valve 54 decompresses the refrigerant by utilizing a throttling operation on the refrigerant.

[0093] The outdoor fan 55 may be an axial flow fan.

[0094] The following introduces the working mode of the duct air conditioner in combination with the refrigerant flow in the refrigerant system.

[0095] First of all, according to the different air circulation in the duct unit, there can be fresh air mode, return air mode and mixed air mode.

[0096] In the fresh air mode, only outdoor fresh air flows through the air duct unit. The air valve at the indoor return air outlet 121 is closed, so that the indoor return air outlet 121 is closed; and the outdoor fresh air outlet 122 is opened.

[0097] In the return air mode, only indoor air circulates in the duct unit. The air valve at the outdoor fresh air outlet 122 is closed, so that the outdoor fresh air outlet 122 is closed; and the indoor return air outlet 121 is opened.

[0098] In the mixed air mode, indoor air and outdoor fresh air flow through the duct unit at the same time. Both the indoor return air vent 121 and the outdoor fresh air vent 122 are open.

[0099] Secondly, the fresh air mode includes fresh air cooling mode, fresh air heating mode, etc.

[0100] The return air mode includes return air cooling mode, return air heating mode, etc.

[0101] The mixed air mode includes mixed air cooling mode, mixed air heating mode, etc.

[0102] <Fresh air cooling mode>

[0103] In some embodiments, reference Figure 6 , the solenoid valve 24 is opened and the indoor expansion valve 23 is closed.

[0104] The compressor 51 compresses the refrigerant to a high pressure, and the four-way valve 53 guides the compressed refrigerant to the outdoor heat exchanger 52. The refrigerant guided to the outdoor heat exchanger 52 is condensed in the outdoor heat exchanger 52, and heat exchange between the refrigerant and the outdoor air is performed while the refrigerant is condensed.

[0105] The outdoor expansion valve 54 decompresses the condensed refrigerant, and the temperature of the refrigerant decreases.

[0106] The low-pressure and low-temperature refrigerant is supplied to the indoor part along the liquid pipe. The refrigerant flows to the first heat exchanger 21 through the opened electromagnetic valve 24 .

[0107] The first heat exchanger 21 evaporates the decompressed liquid refrigerant and performs heat exchange between the refrigerant and outdoor fresh air while the refrigerant evaporates.

[0108] As described above, in the fresh air cooling mode, the refrigerant does not flow through the second heat exchanger 22, that is, the second heat exchanger 22 does not work. The first heat exchanger 21 is used as an evaporator, and the outdoor heat exchanger 52 is used as a condenser.

[0109] Combination Figure 8 , the solid arrows in the figure indicate the flow path of the outdoor fresh air. The outdoor fresh air is cooled when passing through the first heat exchanger 21 and then sent to the room.

[0110] In other embodiments of the fresh air cooling mode, different from the above, reference Figure 5 , the solenoid valve 24 is closed and the indoor expansion valve 23 is fully opened.

[0111] In the indoor side, the refrigerant sequentially flows to the second heat exchanger 22 and the first heat exchanger 21. The second heat exchanger 22 and the first heat exchanger 21 both evaporate the decompressed liquid refrigerant, and perform heat exchange between the refrigerant and the outdoor fresh air while the refrigerant evaporates.

[0112] As described above, in the fresh air cooling mode, the refrigerant flows through the second heat exchanger 22. The second heat exchanger 22 and the first heat exchanger 21 are used as evaporators, and the outdoor heat exchanger 52 is used as a condenser.

[0113] Combination Figure 8 The outdoor fresh air is cooled when passing through the second heat exchanger 22, and then continues to be cooled when passing through the first heat exchanger 21, and is finally sent to the room.

[0114] Some other embodiments of the fresh air cooling mode are a combination of the above two embodiments: the duct unit first opens the solenoid valve 24 and closes the indoor expansion valve 23, and the first heat exchanger 21 cools the outdoor fresh air.

[0115] If the supply air temperature is still significantly different from the user set temperature after the unit has been running for a period of time, the solenoid valve 24 is closed and the indoor expansion valve 24 is fully opened, and the second heat exchanger 22 and the first heat exchanger 21 cool the outdoor fresh air.

[0116] When the first heat exchanger 21 and the second heat exchanger 22 are used as evaporators at the same time, the internal volume of the evaporator can be increased, thereby improving the refrigeration capacity of the unit.

[0117] If the air supply temperature is not much different from the user set temperature after the unit has been running for a period of time, it means that the unit has a good cooling effect. In order to avoid the indoor temperature being too low and causing user discomfort, and to avoid wasting energy, the system switches back to the solenoid valve 24 opening, the indoor expansion valve 23 closing, and only the first heat exchanger 21 cools the outdoor fresh air.

[0118] <Fresh air heating mode>

[0119] In some embodiments, reference Figure 6 , the solenoid valve 24 is opened and the indoor expansion valve 23 is closed.

[0120] The compressor 51 compresses the refrigerant to a high pressure, and the four-way valve 53 guides the compressed refrigerant to the first heat exchanger 21 .

[0121] The refrigerant guided to the first heat exchanger 21 is condensed in the first heat exchanger 21 , and heat exchange between the refrigerant and outdoor fresh air is performed while the refrigerant is condensed.

[0122] The refrigerant continues to flow to the outdoor expansion valve 54 through the opened solenoid valve 24 .

[0123] The outdoor expansion valve 54 decompresses the condensed refrigerant, and the temperature of the refrigerant decreases.

[0124] The outdoor heat exchanger 52 evaporates the decompressed liquid refrigerant, and performs heat exchange between the refrigerant and outdoor air while the refrigerant evaporates.

[0125] As described above, in the fresh air heating mode, the refrigerant does not flow through the second heat exchanger 22, that is, the second heat exchanger 22 does not work. The first heat exchanger 21 is used as a condenser, and the outdoor heat exchanger 52 is used as an evaporator.

[0126] Combination Figure 8 The outdoor fresh air is heated up when passing through the first heat exchanger 21 and then sent to the room.

[0127] In other embodiments of the fresh air cooling mode, different from the above, reference Figure 7 , the solenoid valve 24 is closed and the indoor expansion valve 23 is fully opened.

[0128] In the indoor part, the refrigerant sequentially flows to the first heat exchanger 21 and the second heat exchanger 22. The first heat exchanger 21 and the second heat exchanger 22 both condense the high-temperature and high-pressure refrigerant and perform heat exchange between the refrigerant and the outdoor fresh air while the refrigerant is condensed.

[0129] As described above, in the fresh air cooling mode, the refrigerant flows through the second heat exchanger 22. The second heat exchanger 22 and the first heat exchanger 21 are used as condensers, and the outdoor heat exchanger 52 is used as an evaporator.

[0130] Combination Figure 8 The outdoor fresh air is heated when passing through the second heat exchanger 22, and then continues to be heated when passing through the first heat exchanger 21, and is finally sent to the room.

[0131] Some other embodiments of the fresh air cooling mode are a combination of the above two embodiments: the duct unit first opens the solenoid valve 24 and closes the indoor expansion valve 23 , and the first heat exchanger 21 heats the outdoor fresh air.

[0132] If the supply air temperature is still significantly different from the user set temperature after the unit has been running for a period of time, the solenoid valve 24 is closed and the indoor expansion valve 24 is fully opened, and the second heat exchanger 22 and the first heat exchanger 21 heat the outdoor fresh air.

[0133] When the first heat exchanger 21 and the second heat exchanger 22 are used as condensers at the same time, the internal volume of the condenser can be increased, thereby improving the heating capacity of the unit.

[0134] If the air supply temperature is not much different from the user set temperature after the unit has been running for a period of time, it means that the heating effect of the unit is good. In order to avoid excessive indoor temperature causing user discomfort and to avoid energy waste, the system switches back to the solenoid valve 24 opening and the indoor expansion valve 23 closing, and only the first heat exchanger 21 heats the outdoor fresh air.

[0135] <Return air cooling mode>

[0136] Reference Figure 4 , the solenoid valve 24 is opened, the indoor expansion valve 23 is closed, and the refrigerant does not flow through the second heat exchanger 22.

[0137] The compressor 51 compresses the refrigerant to a high pressure, and the four-way valve 53 guides the compressed refrigerant to the outdoor heat exchanger 52. The refrigerant guided to the outdoor heat exchanger 52 is condensed in the outdoor heat exchanger 52, and heat exchange between the refrigerant and the outdoor air is performed while the refrigerant is condensed.

[0138] The outdoor expansion valve 54 decompresses the condensed refrigerant, and the temperature of the refrigerant decreases.

[0139] The low-pressure and low-temperature refrigerant is supplied to the indoor part along the liquid pipe. The refrigerant flows to the first heat exchanger 21 through the opened electromagnetic valve 24 .

[0140] The first heat exchanger 21 evaporates the decompressed liquid refrigerant and performs heat exchange between the refrigerant and the indoor air while the refrigerant evaporates.

[0141] As described above, in the return air cooling mode, the outdoor heat exchanger 52 functions as a condenser, and the first heat exchanger 21 functions as an evaporator.

[0142] Combination Fig. 9 The dotted arrows in the figure indicate the flow path of the indoor air. The indoor air is cooled by the first heat exchanger 21 and then sent to the room.

[0143] <Return air heating mode>

[0144] Reference Figure 6 , the solenoid valve 24 is opened, the indoor expansion valve 23 is closed, and the refrigerant does not flow through the second heat exchanger 22.

[0145] The compressor 51 compresses the refrigerant to a high pressure, and the four-way valve 53 guides the compressed refrigerant to the first heat exchanger 21 .

[0146] The refrigerant guided to the first heat exchanger 21 is condensed in the first heat exchanger 21 , and heat exchange between the refrigerant and the indoor air is performed while the refrigerant is condensed.

[0147] The refrigerant continues to flow to the outdoor expansion valve 54 through the opened solenoid valve 24 .

[0148] The outdoor expansion valve 54 decompresses the condensed refrigerant, and the temperature of the refrigerant decreases.

[0149] The outdoor heat exchanger 52 evaporates the decompressed liquid refrigerant, and performs heat exchange between the refrigerant and outdoor air while the refrigerant evaporates.

[0150] As described above, in the return air heating mode, the outdoor heat exchanger 52 functions as an evaporator, and the first heat exchanger 21 functions as a condenser.

[0151] Combination Fig. 9 The indoor air is heated by the first heat exchanger 21 and then sent to the room.

[0152] <Mixed air cooling mode>

[0153] In the mixed air cooling mode, usually, the outdoor fresh air temperature is higher than the indoor return air temperature. When the dew point temperature corresponding to the outdoor fresh air temperature is higher than the indoor return air temperature, condensation will occur in the unit. Therefore, in the mixed air cooling mode of the present application, the second heat exchanger 22 is required to first cool the introduced outdoor fresh air.

[0154] Reference Figure 5 , the solenoid valve 24 is closed; the indoor expansion valve 23 is fully open and does not play a throttling role.

[0155] The compressor 51 compresses the refrigerant to a high pressure, and the four-way valve 53 guides the compressed refrigerant to the outdoor heat exchanger 52. The refrigerant guided to the outdoor heat exchanger 52 is condensed in the outdoor heat exchanger 52, and heat exchange between the refrigerant and the outdoor air is performed while the refrigerant is condensed.

[0156] The outdoor expansion valve 54 decompresses the condensed refrigerant, and the temperature of the refrigerant decreases.

[0157] The low-pressure and low-temperature refrigerant is supplied to the second heat exchanger 22 in the indoor side portion along the liquid pipe.

[0158] The second heat exchanger 22 evaporates the decompressed liquid refrigerant and performs heat exchange between the refrigerant and outdoor fresh air while the refrigerant evaporates.

[0159] The first heat exchanger 21 evaporates the refrigerant and performs heat exchange between the refrigerant and the mixed air while the refrigerant evaporates.

[0160] As described above, in the air-mixing cooling mode, the outdoor heat exchanger 52 functions as a condenser, and the first heat exchanger 21 and the second heat exchanger 22 function as evaporators.

[0161] Combination Fig.10 In the figure, the solid arrows indicate the flow path of outdoor fresh air, and the dotted arrows indicate the flow path of indoor air. The outdoor fresh air is first cooled by the second heat exchanger 22 and then mixed with the indoor return air. The mixed air is further cooled by the first heat exchanger 21 and then sent to the room. This can not only improve the refrigeration capacity of the unit and avoid the problem of increased load due to the introduction of fresh air, but also effectively solve the condensation problem of the unit.

[0162] <Mixed air heating mode>

[0163] Normally, the outdoor fresh air temperature is lower than the indoor return air temperature. When the outdoor fresh air temperature is too low, the outdoor fresh air temperature is lower than the dew point temperature corresponding to the indoor working condition, which will cause condensation in the unit. Therefore, in the mixed air heating mode of the present application, the second heat exchanger 22 is required to first heat the introduced outdoor fresh air.

[0164] Reference Figure 7 , the solenoid valve 24 is closed; the indoor expansion valve 23 is fully open and does not play a throttling role.

[0165] The compressor 51 compresses the refrigerant to a high pressure, and the four-way valve 53 guides the compressed refrigerant to the first heat exchanger 21 .

[0166] The refrigerant guided to the first heat exchanger 21 is condensed in the first heat exchanger 21 , and heat exchange between the refrigerant and the mixed air is performed while the refrigerant is condensed.

[0167] The refrigerant flows to the second heat exchanger 22 through the fully opened indoor expansion valve 23, and the second heat exchanger 22 condenses the refrigerant and performs heat exchange between the refrigerant and outdoor fresh air.

[0168] The outdoor expansion valve 54 decompresses the condensed refrigerant, and the temperature of the refrigerant decreases.

[0169] The outdoor heat exchanger 52 evaporates the decompressed liquid refrigerant, and performs heat exchange between the refrigerant and outdoor air while the refrigerant evaporates.

[0170] As described above, in the mixed air heating mode, the outdoor heat exchanger 52 is used as an evaporator, and the first heat exchanger 21 and the second heat exchanger 22 are used as condensers.

[0171] Combination Fig.10 The outdoor fresh air is first heated by the second heat exchanger 22 and then mixed with the indoor return air. The mixed air is further heated by the first heat exchanger 21 and then sent to the room. This can increase the volume of the condenser and improve the heating capacity of the unit, avoid the problem of increased load due to the introduction of fresh air, and effectively solve the condensation problem of the unit.

[0172] During the heating operation of the duct unit, frost may form on the outdoor heat exchanger 52, and the unit needs to be defrosted.

[0173] <Defrosting operation>

[0174] Reference Figure 5 , the solenoid valve 24 is closed; the outdoor expansion valve 54 is fully open and does not play a throttling role.

[0175] The compressor 51 compresses the refrigerant to a high pressure, and the four-way valve 53 guides the compressed refrigerant to the outdoor heat exchanger 52. The refrigerant guided to the outdoor heat exchanger 52 is condensed in the outdoor heat exchanger 52, and heat exchange between the refrigerant and the outdoor air is performed while the refrigerant is condensed.

[0176] After passing through the fully opened outdoor expansion valve 54, the refrigerant flows to the second heat exchanger 22. The second heat exchanger 22 condenses the refrigerant and performs heat exchange between the refrigerant and the outdoor fresh air while condensing the refrigerant.

[0177] The indoor expansion valve 23 decompresses the condensed refrigerant, and the temperature of the refrigerant decreases.

[0178] The first heat exchanger 21 evaporates the decompressed liquid refrigerant and performs heat exchange between the refrigerant and outdoor fresh air while the refrigerant evaporates.

[0179] As described above, in the defrosting operation, the outdoor heat exchanger 52 and the second heat exchanger 22 function as a condenser, and the first heat exchanger 21 functions as an evaporator.

[0180] Since the high-temperature gaseous refrigerant compressed by the compressor 51 flows through the outdoor heat exchanger 52 , the frost layer of the outdoor heat exchanger 52 can be effectively melted.

[0181] Combination Figure 8 , the indoor return air inlet 121 is closed, the outdoor fresh air inlet 122 is opened, the outdoor fresh air is heated when passing through the second heat exchanger 22, cooled when passing through the first heat exchanger 21, and then sent to the room. Since the outdoor fresh air is heated after passing through the second heat exchanger 22, even if it is cooled at the first heat exchanger 21, the temperature of the outdoor fresh air sent to the room will not be too low. Therefore, the fan 30 in the duct unit does not need to be turned off during defrosting operation, which can effectively ensure the reliability of the unit operation.

[0182] As described above, according to the duct air conditioner of the embodiment of the present application, outdoor fresh air can be introduced into the room by providing an outdoor fresh air outlet 122 connected to the outdoor air on the duct air conditioner; by providing a second heat exchanger 22 on the air inlet side of the outdoor fresh air, the outdoor fresh air can be preheated or precooled by the second heat exchanger 22, thereby avoiding condensation problems caused by the large temperature difference between the outdoor fresh air and the indoor air when the unit introduces fresh air.

[0183] In addition, the mixing area of ​​outdoor fresh air and indoor air in the duct unit is located between the second heat exchanger 22 and the first heat exchanger 21, so that the outdoor fresh air is mixed with the indoor air after being preheated / precooled by the second heat exchanger 22, thereby avoiding the generation of condensation in the unit.

[0184] In addition, the solenoid valve 24 is connected in parallel to the first branch of the second heat exchanger 22 and the indoor expansion valve 23 in series. When fresh air is introduced, the opening and closing states of the indoor expansion valve 23 and the solenoid valve 24 can be used to determine whether the second heat exchanger 22 is functional. Thus, when the difference between the supply air temperature and the set temperature is small, the second heat exchanger 22 is selected to be inactive, so as to avoid energy waste and poor user experience due to too low / too high indoor temperature. When the difference between the supply air temperature and the set temperature is large, the second heat exchanger 22 is selected to be functional, so as to improve the cooling / heating capacity of the unit.

[0185] In addition, a solenoid valve 24 is provided in the refrigerant system, and the second heat exchanger 22 can be used as a condenser when the unit is defrosting by adjusting the opening and closing status of the outdoor expansion valve 54 and the solenoid valve 24. The outdoor fresh air is first heated by the second heat exchanger 22, so that the temperature of the introduced outdoor fresh air will not be too low, thereby improving the user's comfort. The fan 30 of the duct machine does not need to be turned off, which can effectively ensure the reliability of the unit's operation.

[0186] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

[0187] For the convenience of explanation, the above description has been made in conjunction with specific embodiments. However, the above exemplary discussion is not intended to be exhaustive or limit the embodiments to the specific forms disclosed above. Based on the above teachings, various modifications and variations can be obtained. The selection and description of the above embodiments are to better explain the principles and practical applications, so that those skilled in the art can better use the embodiments and various different variations of the embodiments suitable for specific use considerations.

Claims

1. A duct machine, characterized in that: include: A housing, on which an air inlet and an air supply outlet are provided, wherein the air inlet includes an indoor return air outlet and an outdoor fresh air outlet; A first heat exchanger is disposed in the housing corresponding to the air supply port; A second heat exchanger is arranged corresponding to the outdoor fresh air outlet, and the second heat exchanger is located on the windward side of the first heat exchanger; The duct machine also includes an indoor expansion valve and a solenoid valve; In the refrigerant system of the duct unit, the liquid-side stop valve, the second heat exchanger, the indoor expansion valve, the first heat exchanger, and the gas-side stop valve are connected in series in sequence; The second heat exchanger and the indoor expansion valve form a first branch, and the solenoid valve is connected in parallel with the first branch; The duct unit allows indoor air to flow to the supply air outlet through the indoor return air outlet and the first heat exchanger; the duct unit allows outdoor fresh air to flow to the supply air outlet through the outdoor fresh air outlet, the second heat exchanger, and the first heat exchanger.

2. The air duct machine according to claim 1, characterized in that: Part of the space in the shell near the air inlet is the air inlet space; The air duct machine also includes: A fan, disposed between the air inlet space and the first heat exchanger, for driving the flow of indoor air and outdoor fresh air; An air baffle is provided in the shell, and the air baffle divides the air inlet space into an indoor air inlet space connected to the indoor return air outlet, and a fresh air inlet space connected to the outdoor fresh air outlet; the second heat exchanger is arranged in the fresh air inlet space.

3. The air duct machine according to claim 2, characterized in that: There is a gap between the wind baffle and the fan to form a mixed air space for outdoor fresh air and indoor air.

4. The air duct machine according to claim 1, characterized in that: Part of the space in the shell near the air inlet is the air inlet space; the first heat exchanger is located between the air inlet space and the air supply port; A wind baffle is provided in the shell, and the wind baffle divides the air inlet space into an indoor air inlet space connected to the indoor return air outlet, and a fresh air inlet space connected to the outdoor fresh air outlet; The air duct machine also includes: A first fan, disposed in the indoor air inlet space, for driving indoor air to blow toward the first heat exchanger; The second fan is arranged in the fresh air inlet space and is used for driving outdoor fresh air to blow toward the first heat exchanger.

5. The air duct machine according to claim 4, characterized in that: There is a gap between the air inlet space and the first heat exchanger to form a mixed air space for outdoor fresh air and indoor air.

6. The air duct machine according to claim 4, characterized in that: Taking the flow path of outdoor fresh air as a reference, the second fan is located downstream of the second heat exchanger.

7. The air duct machine according to claim 1, characterized in that: An air outlet flange is provided at the indoor return air outlet, and a plurality of knock-off plates are stacked in the air outlet flange along the radial direction.

8. The air duct machine according to any one of claims 1 to 7, characterized in that: In the refrigerant system, an outdoor expansion valve is connected in series between the outdoor heat exchanger and the liquid-side stop valve; When the duct unit is in defrosting operation, the outdoor expansion valve is in a fully open state, the solenoid valve is in a closed state, the outdoor heat exchanger and the second heat exchanger are used as condensers, and the first heat exchanger is used as an evaporator; The air duct unit allows outdoor fresh air to pass through the second heat exchanger and the first heat exchanger in sequence and blow into the room.

9. The air duct machine according to any one of claims 1 to 7, characterized in that: When the duct air conditioner operates in the mixed air mode, the solenoid valve is in a closed state and the indoor expansion valve is in a fully open state, so that the second heat exchanger and the first heat exchanger are both used as evaporators in cooling and as condensers in heating.

10. A duct machine, characterized in that: include: A housing, on which an air inlet and an air supply outlet are provided, wherein the air inlet includes an indoor return air outlet and an outdoor fresh air outlet; A first heat exchanger is disposed in the housing corresponding to the air supply port; A second heat exchanger is provided corresponding to the outdoor fresh air outlet, the second heat exchanger is located on the windward side of the first heat exchanger, and the second heat exchanger can be used as an evaporator in cooling and as a condenser in heating; The air duct unit allows indoor air to flow to the air supply outlet through the indoor return air outlet and the first heat exchanger, and allows outdoor fresh air to flow to the air supply outlet through the outdoor fresh air outlet, the second heat exchanger, and the first heat exchanger.

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