Fresh air air conditioner and corresponding control method thereof

Abstract

The application provides a fresh air conditioner and a corresponding control method thereof. The fresh air conditioner comprises an indoor unit module having a fresh air channel and an exhaust air channel. The fresh air channel is provided with a first heat exchanger and a second heat exchanger located at the air inlet side of the first heat exchanger. The first heat exchanger is close to a fresh air outlet. The exhaust air channel is provided with a third heat exchanger. A backflow port is formed on a partition plate. The backflow port connects the air inlet side space of the second heat exchanger with the air outlet side space of the third heat exchanger. The fresh air conditioner further comprises an outdoor heat exchanger and an intermediate heat exchanger. The first heat exchanger, the third heat exchanger and a first heat exchange flow channel in the intermediate heat exchanger are connected in series to form a first flow path. A second heat exchange flow channel in the intermediate heat exchanger and the second heat exchanger are connected in series to form a second flow path. The first flow path and the second flow path are connected in parallel. The system has low power consumption. Fresh air and return air are sent into a room after being dehumidified and heated, and the comfort level is high.

Description

Technical Field

[0001] This invention belongs to the field of air conditioning technology, specifically relating to a fresh air air conditioner and its corresponding control method. Background Technology

[0002] As customers' requirements for air temperature and humidity continue to increase, the demands for temperature and humidity control in air handling units are also gradually strengthening. Currently, the common approach is to address the issue of decreased comfort due to excessively low outlet air temperature during cooling and dehumidification processes by adopting independent temperature and humidity control methods. However, the existing dehumidification and temperature control systems in fresh air handling units clearly still have inconveniences and shortcomings in terms of structure and use, and urgently need further improvement. Specifically, existing fresh air conditioning technologies mostly use multiple (at least two) units to control and adjust temperature and humidity separately, which results in relatively high system energy consumption. Summary of the Invention

[0003] Therefore, the present invention provides a fresh air conditioner and its corresponding control method, which can solve the technical problem of excessive power consumption in the temperature and humidity adjustment system of the existing fresh air conditioner.

[0004] To address the aforementioned problems, this invention provides a fresh air air conditioner, including an indoor unit module corresponding to an indoor space. The indoor unit module includes an indoor unit housing. A partition within the indoor unit housing divides the internal space of the housing into a fresh air duct and an exhaust air duct. The fresh air duct has a fresh air inlet selectively connected to the external environment and a fresh air outlet selectively connected to the indoor space. The exhaust air duct has an exhaust air outlet selectively connected to the external environment and an exhaust air inlet selectively connected to the indoor space. The fresh air duct is equipped with a first heat exchanger and a second heat exchanger located on the air inlet side of the first heat exchanger, wherein the first heat exchanger is close to the fresh air outlet. The exhaust air duct is equipped with a third heat exchanger. The device includes a reflux port on the partition, which connects the air inlet space of the second heat exchanger with the air outlet space of the third heat exchanger. The fresh air air conditioner also includes an outdoor heat exchanger and an intermediate heat exchanger. The first heat exchanger, the third heat exchanger, and the first heat exchange channel in the intermediate heat exchanger are connected in series to form a first flow path. The second heat exchange channel in the intermediate heat exchanger and the second heat exchanger are connected in series to form a second flow path. The first flow path and the second flow path are connected in parallel. The first end of the first flow path and the first end of the second flow path are connected to the side of the outdoor heat exchanger away from the compressor exhaust port. The second end of the first flow path and the second end of the second flow path are connected to the compressor intake port.

[0005] In some embodiments, a first throttling element and a second throttling element are connected in series in the first flow path. The first throttling element is located between the outdoor heat exchanger and the first heat exchanger, and the second throttling element is located between the first heat exchanger and the third heat exchanger.

[0006] In some implementations...

[0007] A third throttling element is also connected in series in the second flow path, and the third throttling element is located between the intermediate heat exchanger and the second heat exchanger.

[0008] In some implementations...

[0009] A third shut-off valve is connected in series in the first flow path. The third shut-off valve is located on the side of the intermediate heat exchanger away from the third heat exchanger. A second shut-off valve and a first shut-off valve are connected in series in the second flow path. The second shut-off valve is located on the pipe section of the second flow path near the outdoor heat exchanger, and the first shut-off valve is located on the pipe section of the second flow path near the suction port of the compressor.

[0010] In some embodiments, a four-way reversing valve is also included, wherein the first port of the four-way reversing valve is connected to the exhaust port of the compressor, the second port is connected to the first end of the outdoor heat exchanger, the third port is connected to the suction port of the compressor, and the fourth port is connected to the second end of the first flow path and the second flow path connected in parallel.

[0011] In some embodiments, a fresh air valve is provided in the fresh air inlet, an exhaust air valve is provided in the exhaust air outlet, and a return air valve is provided in the return port.

[0012] In some embodiments, a humidifying component is also provided in the fresh air duct, and the humidifying component is located on the air outlet side of the first heat exchanger.

[0013] The present invention also provides a control method for a fresh air conditioner as described above, comprising the following steps:

[0014] Obtain the operating mode of the fresh air conditioner;

[0015] Based on the obtained operating mode, control the opening and closing of the fresh air inlet, exhaust air outlet and return outlet, and control the on / off of the first flow path and the second flow path.

[0016] In some implementations...

[0017] When the operating mode is dehumidification mode, the fresh air inlet, exhaust outlet and return outlet are all opened, and the first flow path and the second flow path are both connected.

[0018] In some implementations...

[0019] When the first throttling element, the second throttling element, and the third throttling element are included, the first throttling element, the second throttling element, and the third throttling element are all controlled to be in a throttling state.

[0020] In some implementations...

[0021] When the operating mode is dehumidification and heating mode, the fresh air inlet and exhaust outlet are opened and the return outlet is closed, and the first flow path is opened and the second flow path is cut off.

[0022] In some implementations...

[0023] When the fresh air air conditioner also includes a four-way reversing valve and the operating mode is cooling mode, the four-way reversing valve is controlled to be in cooling state, the fresh air inlet and exhaust outlet are both closed, the return outlet is opened, and the second flow path is opened while the first flow path is cut off; or,

[0024] When the fresh air air conditioner also includes a four-way reversing valve and the operating mode is heating mode, the four-way reversing valve is controlled to be in heating mode, the fresh air inlet and exhaust outlet are both closed and the return port is opened, and the second flow path is opened and the first flow path is cut off.

[0025] The present invention provides a fresh air conditioner and a corresponding control method thereof, which have the following beneficial effects:

[0026] When the fresh air conditioner is in dehumidification mode, the first and second flow paths are connected simultaneously. The indoor return air undergoes two-stage dehumidification at the third and second heat exchangers, while the outdoor fresh air is dehumidified at the second heat exchanger. After being dehumidified, the indoor return air and fresh air are mixed and heated at the first heat exchanger to prevent the dehumidified cold air from being directly sent into the indoor space and causing discomfort to the user. At the same time, the refrigerant in the first and second flow paths exchange heat at the intermediate heat exchanger. The refrigerant in the second flow path is subcooled by the refrigerant in the first flow path before entering the second heat exchanger, resulting in a lower evaporation temperature in the second heat exchanger, which fully meets the condensation dehumidification needs of the fresh air and indoor return air. Attached Figure Description

[0027] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings in the following description are merely exemplary, and those skilled in the art can derive other embodiments based on the provided drawings without creative effort.

[0028] The structures, proportions, sizes, etc. illustrated in this specification are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed herein, and are not intended to limit the conditions under which the present invention can be implemented. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportions, or adjustments to the size, without affecting the effects and objectives that the present invention can produce, should still fall within the scope of the technical content disclosed in the present invention.

[0029] Figure 1 This is a system schematic diagram of a fresh air conditioner according to an embodiment of the present invention;

[0030] Figure 2 This is a schematic diagram (state illustration) of the refrigerant flow direction when the fresh air air conditioner is operating in dehumidification mode according to an embodiment of the present invention;

[0031] Figure 3 This is a schematic diagram (state illustration) of the refrigerant flow direction when the fresh air air conditioner is operating in dehumidification and heating mode according to an embodiment of the present invention;

[0032] Figure 4 This is a schematic diagram (state illustration) of the refrigerant flow direction when the fresh air air conditioner is operating in cooling mode according to an embodiment of the present invention;

[0033] Figure 5 This is a schematic diagram (state illustration) of the refrigerant flow direction when the fresh air air conditioner is operating in heating mode according to an embodiment of the present invention;

[0034] Figure 6 This is a schematic diagram of the control logic of a fresh air conditioner according to another embodiment of the present invention (excluding the heating mode);

[0035] Figure 7 This is a schematic diagram of the control logic of a fresh air conditioner in heating mode according to another embodiment of the present invention.

[0036] The reference numerals in the attached figures are as follows:

[0037] 1. Indoor unit casing; 11. Partition;

[0038] 21. First heat exchanger; 22. Second heat exchanger; 23. Third heat exchanger; 24. Outdoor heat exchanger; 25. Intermediate heat exchanger;

[0039] 3. Compressor;

[0040] 41. First throttling element; 42. Second throttling element; 43. Third throttling element;

[0041] 51. First shut-off valve; 52. Second shut-off valve; 53. Third shut-off valve;

[0042] 6. Four-way directional valve;

[0043] 71. Fresh air damper; 72. Exhaust air damper; 73. Return air damper;

[0044] 8. Humidification components;

[0045] 91. Air outlet temperature sensor; 92. Indoor temperature and humidity sensor; 93. Outdoor temperature and humidity sensor;

[0046] 101. Fresh air duct; 1011. Fresh air inlet; 1012. Fresh air outlet; 102. Exhaust duct; 1021. Exhaust outlet; 1022. Exhaust inlet;

[0047] 103. Fresh air fan; 104. Exhaust fan. Detailed Implementation

[0048] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0049] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0050] It should be understood that the term "and / or" used in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0051] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the invention. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0052] In the description of this invention, it should be understood that the orientation or positional relationship indicated by directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" is generally based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this invention and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this invention; the directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0053] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0054] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore should not be construed as limiting the scope of protection of this invention.

[0055] See also Figure 1and Figure 7 As shown in the figure, according to an embodiment of the present invention, a fresh air air conditioner is provided, including an indoor unit module (not shown) corresponding to an indoor space. The indoor unit module includes an indoor unit housing 1. A partition 11 inside the indoor unit housing 1 divides the internal space of the indoor unit housing 1 into a fresh air channel 101 and an exhaust air channel 102. The fresh air channel 101 has a fresh air inlet 1011 selectively connected to the external environment and a fresh air outlet 1012 selectively connected to the indoor space. The exhaust air channel 102 has an exhaust air outlet 1021 selectively connected to the external environment and an exhaust air inlet 1022 selectively connected to the indoor space. The fresh air channel 101 is provided with a first heat exchanger 21 and a... The first heat exchanger 21 has a second heat exchanger 22 on its air inlet side. The first heat exchanger 21 is located near the fresh air outlet 1012. This means that fresh air entering through the fresh air inlet 1011 can flow sequentially through the second heat exchanger 22 and the first heat exchanger 21 before being sent into the indoor space through the fresh air outlet 1012. A third heat exchanger 23 is provided within the exhaust duct 102. The partition 11 has a return port, which connects the air inlet space of the second heat exchanger 22 with the air outlet space of the third heat exchanger 23. That is, indoor return air entering through the exhaust inlet 1022 can enter the fresh air duct 101 through the return port and exchange heat again with the heat exchangers in the fresh air duct 101 before being sent into the indoor space. (Continue to the previous section...) Figure 1 As shown, the fresh air air conditioner also includes an outdoor heat exchanger 24 and an intermediate heat exchanger 25. The first heat exchanger 21, the third heat exchanger 23 and the first heat exchange channel in the intermediate heat exchanger 25 are connected in series to form a first flow path. The second heat exchange channel in the intermediate heat exchanger 25 and the second heat exchanger 22 are connected in series to form a second flow path. The first flow path and the second flow path are connected in parallel. The first end of the first flow path and the first end of the second flow path are connected to the side of the outdoor heat exchanger 24 away from the exhaust port of the compressor 3. The second end of the first flow path and the second end of the second flow path can be connected to the intake port of the compressor 3.

[0056] In this technical solution, when the fresh air air conditioner is operating in dehumidification mode, the first flow path and the second flow path are simultaneously connected. The indoor return air undergoes two-stage dehumidification at the third heat exchanger 23 and the second heat exchanger 22, while the outdoor fresh air is dehumidified at the second heat exchanger 22. After the dehumidified indoor return air is mixed with the fresh air, it is heated at the first heat exchanger 21 to prevent the dehumidified cold air from being directly sent into the indoor space and causing discomfort to the user. At the same time, the refrigerant in the first flow path and the refrigerant in the second flow path exchange heat at the intermediate heat exchanger 25. The refrigerant in the second flow path is subcooled by the refrigerant in the first flow path before entering the second heat exchanger 22, resulting in a lower evaporation temperature in the second heat exchanger 22. This fully meets the condensation and dehumidification requirements of the fresh air and the indoor return air. Since the first flow path and the second flow path exchange heat at the intermediate heat exchanger 25, the energy efficiency of the air conditioning system can be improved and the system power consumption can be reduced.

[0057] In some embodiments, a first throttling element 41 and a second throttling element 42 are connected in series in the first flow path. The first throttling element 41 is located between the outdoor heat exchanger 24 and the first heat exchanger 21, and the second throttling element 42 is located between the first heat exchanger 21 and the third heat exchanger 23. The aforementioned throttling element may specifically be an electronic expansion valve.

[0058] By setting a first throttling element 41 between the outdoor heat exchanger 24 and the first heat exchanger 21, and setting a second throttling element 42 between the first heat exchanger 21 and the third heat exchanger 23, the evaporation temperature of the first heat exchanger 21 and the third heat exchanger 23 can be adjusted by adjusting the opening of the first throttling element 41 and the second throttling element 42, thereby enabling reasonable adjustment according to the actual humidity and temperature of the indoor space.

[0059] A third throttling element 43 is also connected in series in the second flow path, and the third throttling element 43 is located between the intermediate heat exchanger 25 and the second heat exchanger 22.

[0060] In this technical solution, the refrigerant in the second flow path is throttled and adjusted by connecting a third throttling element 43 in series between the intermediate heat exchanger 25 and the second heat exchanger 22. In this way, the refrigerant flow in the second flow path can be adjusted separately to realize the adjustment of the cooling mode and heating mode of the fresh air air conditioner of the present invention.

[0061] In some implementations...

[0062] A third shut-off valve 53 is connected in series in the first flow path. The third shut-off valve 53 is located on the side of the intermediate heat exchanger 25 away from the third heat exchanger 23. A second shut-off valve 52 and a first shut-off valve 51 are connected in series in the second flow path. The second shut-off valve 52 is located on the pipe section of the second flow path near the outdoor heat exchanger 24, and the first shut-off valve 51 is located on the pipe section of the second flow path near the suction port of the compressor 3. Each of the aforementioned shut-off valves can be a solenoid valve.

[0063] In this technical solution, by setting the aforementioned third shut-off valve 53, second shut-off valve 52 and first shut-off valve 51 on the first flow path and the second flow path respectively, the refrigerant flow in the first flow path and the second flow path can be conditioned, so that the refrigerant in the fresh air air conditioner flows to different pipelines under different operating modes.

[0064] To further enrich the operating modes of the fresh air conditioner of the present invention, in some embodiments, the fresh air conditioner also includes a four-way reversing valve 6. The first port of the four-way reversing valve 6 is connected to the exhaust port of the compressor 3, the second port is connected to the first end of the outdoor heat exchanger 24, the third port is connected to the intake port of the compressor 3, and the fourth port is connected to the second end of the first and second flow paths connected in parallel. This allows the fresh air conditioner to switch between heating and cooling modes by changing the state of the four-way reversing valve 6. Specifically, see [reference needed]. Figures 1 to 5 As shown, the four-way reversing valve 6 has a heating state and a cooling state. That is, when the fresh air air conditioner is running in heating mode, the four-way reversing valve 6 is adjusted to the heating state. In this state, the first port and the fourth port of the four-way reversing valve 6 are connected, and the second port and the third port are connected. In the cooling mode, dehumidification mode, and dehumidification heating mode, the four-way reversing valve 6 is adjusted to the cooling state. In this state, the first port and the second port of the four-way reversing valve 6 are connected, and the third port and the fourth port are connected.

[0065] In order to control the introduction of fresh air, the return air of indoor return air, or the exhaust air, a fresh air valve 71 is provided in the fresh air inlet 1011, an exhaust air valve 72 is provided in the exhaust air outlet 1021, and a return air valve 73 is provided in the return port. The aforementioned valves can be valve components in the prior art, and the present invention does not particularly limit their specific structure.

[0066] Specifically, when the fresh air conditioner is operating in dehumidification mode, the fresh air valve 71 and return air valve 73 are opened, and the exhaust air valve 72 is closed. At this time, the fresh air fan 103 corresponding to the first heat exchanger 21 and the exhaust fan 104 corresponding to the third heat exchanger 23 both operate, and outdoor fresh air is driven to enter the fresh air duct 101, while indoor return air enters the fresh air duct 101 through the exhaust air duct 102 and the flow hole. When the fresh air conditioner is operating in dehumidification and heating mode, both the fresh air valve 71 and the exhaust air valve 72 are opened. When the open and return air dampers 73 are closed, both the fresh air fan 103 and the exhaust fan 104 are running. Outdoor fresh air is driven into the fresh air duct 101, while indoor return air is driven to be discharged to the outside through the exhaust duct 102. When the fresh air air conditioner is running in heating or cooling mode, the fresh air damper 71 and the exhaust air damper 72 are closed and the return air damper 73 is opened. At this time, the fresh air fan 103 drives the indoor return air to enter the exhaust duct 102, where it exchanges heat at the second heat exchanger 22 and is then sent into the room through the fresh air outlet 1012.

[0067] In some embodiments, the fresh air duct 101 is further provided with a humidifying component 8, which is located on the air outlet side of the first heat exchanger 21. The aforementioned humidifying component 8 is, for example, an existing ultrasonic humidifier.

[0068] In this technical solution, by setting a humidifying component 8 on the air outlet side of the first heat exchanger 21, its operation can be controlled to humidify the indoor air conditioner when the indoor humidity is too low, thereby improving the user's comfort.

[0069] According to an embodiment of the present invention, a control method for a fresh air conditioner as described above is also provided, comprising the following steps:

[0070] Obtain the operating mode of the fresh air conditioner;

[0071] Based on the obtained operating mode, the opening and closing of the fresh air inlet 1011, the exhaust outlet 1021 and the return outlet are controlled, and the on / off of the first flow path and the second flow path are controlled.

[0072] In this technical solution, after obtaining the operating mode of the fresh air conditioner, the system controls the opening and closing of each air outlet and the switching on and off of the first and second flow paths to achieve targeted operation of different operating modes, making the system control simple.

[0073] When the operating mode is dehumidification mode, the fresh air inlet 1011, the exhaust outlet 1021 and the return outlet are all opened, and the first flow path and the second flow path are both connected. Furthermore, when the first throttling element 41, the second throttling element 42 and the third throttling element 43 are included, the first throttling element 41, the second throttling element 42 and the third throttling element 43 are all in a throttling state.

[0074] See details Figure 2 As shown, in this mode, all solenoid valves (i.e., the aforementioned shut-off valves, the same below) are open, and all electronic expansion valves (i.e., the aforementioned throttling elements, the system) are controlled; fresh air + return air is used, the fresh air valve 71 is opened, the exhaust air valve 72 is closed, the return air valve 73 is opened, and both the fresh air fan 103 and the exhaust fan 104 are turned on.

[0075] The system flow is as follows: The high-temperature and high-pressure refrigerant discharged from the compressor 3 flows to the outdoor heat exchanger 24 through the four-way reversing valve 6. After being condensed in the outdoor heat exchanger 24, the refrigerant is divided into two paths. The first path (i.e., the first flow path, the same below) is throttled and depressurized for the first time through the first throttling element 41 and enters the first heat exchanger 21 (the refrigerant in the second heat exchanger is in a medium-pressure and medium-temperature state) to exchange heat with the air, heating the air and sending it into the room, avoiding the direct delivery of dehumidified cold air into the room, thereby improving comfort. Afterwards, the refrigerant is throttled and depressurized again through the second throttling element 42 and evaporates and absorbs heat in the third heat exchanger 23. Then it flows to the intermediate heat exchanger 25, where it exchanges heat with another refrigerant (i.e., the second flow path mentioned above, the same below) and absorbs heat from the other refrigerant. Then it passes through the third shut-off valve 53 and merges with the other refrigerant. The other refrigerant coming out of the outdoor heat exchanger 24 passes through the intermediate heat exchanger 25 and is cooled again by the refrigerant flowing from the third heat exchanger 23. It undergoes subcooling treatment, and then it is throttled by the third throttling element 43 and evaporates and absorbs heat in the second heat exchanger 22. After merging with the other refrigerant, it flows through the four-way reversing valve 6 and is drawn into the compressor 3, completing one cycle.

[0076] In this mode, the indoor temperature and humidity are high. After the exhaust fan and return air valve 73 are opened, the indoor return air passes through the third heat exchanger 23 and the second heat exchanger 22 twice for dehumidification and cooling, which can quickly dehumidify the air. After mixing with the fresh air entering the room, the air passes through the first heat exchanger 21 and is reheated by medium-pressure refrigerant. This avoids directly sending the dehumidified cold air into the room, thereby improving comfort.

[0077] To adjust the unit's outlet air temperature, the intermediate pressure temperature of the first heat exchanger 21 can be adjusted. This intermediate pressure temperature is controlled by the compressor frequency and the first throttling element 41. To increase the intermediate pressure temperature, the first throttling element 41 can be increased, or the compressor frequency can be raised. To decrease the intermediate pressure temperature, the first throttling element 41 can be decreased, or the compressor frequency can be lowered. The dehumidification temperatures of the third heat exchanger 23 and the second heat exchanger 22 can be controlled by the second throttling element 42 and the third throttling element 43, respectively, to maintain the refrigerant evaporation temperature Tz = TL - A℃ (where A is the set difference, which can be 5℃, and TL is the dew point temperature). Simultaneously, the refrigerant that has expanded and evaporated in the third heat exchanger 23 can be recooled through the intermediate heat exchanger 25, thereby achieving a lower evaporation temperature for the refrigerant in the second heat exchanger 22.

[0078] In some implementations, when the operating mode is dehumidification and heating mode, the fresh air inlet 1011 and the exhaust outlet 1021 are opened and the return outlet is closed, and the first flow path is opened and the second flow path is cut off.

[0079] See details Figure 3 As shown, in this mode, the second shut-off valve 52 is closed and the first shut-off valve 51 is closed; fresh air + exhaust air is used, the fresh air valve 71 is open, the exhaust air valve 72 is open, the return air valve 73 is closed, and both the fresh air fan 103 and the exhaust fan 104 are open.

[0080] The system flow is as follows: The high-temperature and high-pressure refrigerant discharged from the compressor 3 flows to the outdoor heat exchanger 24 through the four-way reversing valve 6 and is condensed. After being throttled by the first throttling element 41, it enters the first heat exchanger 21 to release heat. After being throttled by the second throttling element 42, it enters the third heat exchanger 23 to evaporate and absorb heat. After passing through the intermediate heat exchanger 25, the third shut-off valve 53 flows through the four-way reversing valve 6 and is drawn into the compressor 3, completing one cycle.

[0081] See also Figure 6 As shown in the flowchart, in this mode, the indoor temperature is low but the humidity is high. Therefore, outdoor air is introduced into the room, and the low-temperature, high-humidity indoor air is exhausted to the outside, reducing the indoor humidity at the same time. In this mode, the refrigerant passing through the first throttling element 41 undergoes one throttling, and the refrigerant temperature entering the first heat exchanger is medium pressure, which can heat the fresh air before it is sent into the room. The refrigerant after being throttled by the second throttling element 42 recovers and utilizes the heat in the exhaust air in the third heat exchanger 23. The fresh air supply temperature control, which is the control of the medium pressure temperature, is achieved by adjusting the first throttling element 41 or the compressor frequency. When the temperature is low, the compressor frequency is increased or the first throttling element 41 is opened wider; when the temperature is high, the first throttling element 41 is closed or the compressor frequency is reduced.

[0082] When the fresh air air conditioner also includes a four-way reversing valve 6 and the operating mode is cooling mode, the four-way reversing valve 6 is controlled to be in cooling state, the fresh air inlet 1011 and the exhaust outlet 1021 are both closed and the return port is opened, and the second flow path is controlled to be open and the first flow path is cut off.

[0083] See details Figure 4 As shown, in this mode, the first throttling element 41 is closed, the third shut-off valve 53 is closed; the fresh air valve 71 is closed, the exhaust air valve 72 is closed, the return air valve 73 is open, the fresh air fan 103 is open, and the exhaust fan 104 is closed.

[0084] The system flow is as follows: The high-temperature and high-pressure refrigerant discharged from the compressor 3 flows to the outdoor heat exchanger 24 through the four-way reversing valve 6 and is condensed. Then it flows through the intermediate heat exchanger 25, and after being throttled by the third throttling element 43, it enters the second heat exchanger 22 to evaporate and absorb heat, exchange heat with the return air, take away the heat from the air, and cool the air. Then it flows through the four-way reversing valve 6 again and is drawn into the compressor 3 to complete one cycle.

[0085] In this mode, a return air is used. At this time, the indoor temperature is high and the humidity is low. The system controls the evaporation temperature Tz of the second heat exchanger 22 by adjusting the third throttling element 43, which is Tz = f(TL, Tw, RH%) (this formula is an empirical formula obtained through testing). This ensures that the humidity does not decrease while the temperature is being lowered. At the same time, by using a return air method, the indoor temperature can be quickly reduced to the set temperature.

[0086] or,

[0087] When the fresh air air conditioner also includes a four-way reversing valve 6 and the operating mode is heating mode, the four-way reversing valve 6 is controlled to be in heating mode, the fresh air inlet 1011 and the exhaust outlet 1021 are both closed and the return port is opened, and the second flow path is controlled to be open and the first flow path is cut off.

[0088] See details Figure 5 As shown, in this mode, the first throttling element 41 is closed, the third shut-off valve 53 is closed, the four-way reversing valve 6 is reversed, and return air is used. The fresh air valve 71 is closed, the exhaust air valve 72 is closed, the return air valve 73 is open, the fresh air fan 103 is on, and the exhaust fan 104 is off. The high-temperature and high-pressure gas discharged from the compressor 3 flows through the four-way reversing valve 6 to the second heat exchanger 22, where it exchanges heat with the air. After being throttled by the third throttling element 43, it enters the intermediate heat exchanger 25. After evaporating and absorbing heat in the outdoor heat exchanger 24, it is drawn into the compressor through the four-way reversing valve 6, completing one cycle.

[0089] In this mode, the air supply temperature is mainly regulated by the compressor frequency. When Tw < Ts - T1℃ (T1 is the set deviation temperature, ranging from 0 to 2℃, and can be taken as 1℃), the compressor frequency is increased; when Tw > Ts - T1℃, the compressor frequency is decreased. Humidity is controlled by the humidifier 8; if the humidity is insufficient, the humidifier 8 is turned on; if the humidity is high, the humidifier 8 is turned off.

[0090] It is understandable that the dehumidification mode, dehumidification heating mode, cooling mode, and heating mode of the aforementioned fresh air conditioner have different refrigerant flow directions in the heating mode compared to the other three modes. Regarding the acquisition of commands for these operating modes, manual selection can be used to switch modes. However, to enhance the intelligence of the fresh air conditioner, the system can also obtain relevant temperature and humidity parameters, such as indoor temperature Tw and indoor relative humidity RH, from sensors like the outlet air temperature sensor 91, indoor temperature and humidity sensor 92, and outdoor temperature and humidity sensor 93. These parameters are compared with the corresponding set values ​​Ts and RH1 to intelligently switch operating modes. For details, please refer to [link to relevant documentation]. Figure 6 and Figure 7 As shown.

[0091] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention. The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the protection scope of the present invention.

Claims

1. A fresh air conditioner, comprising an indoor unit module arranged corresponding to an indoor space, the indoor unit module comprising an indoor unit shell (1), characterized in that, the indoor unit shell (1) has a partition plate (11) inside, which separates the internal space of the indoor unit shell (1) into a fresh air channel (101) and an exhaust air channel (102), the fresh air channel (101) has a fresh air inlet (1011) selectively communicating with an external environment and a fresh air outlet (1012) selectively communicating with the indoor space, the exhaust air channel (102) has an exhaust air outlet (1021) selectively communicating with the external environment and an exhaust air inlet (1022) selectively communicating with the indoor space, the fresh air channel (101) is provided with a first heat exchanger (21) and a second heat exchanger (22) at the air inlet side of the first heat exchanger (21), wherein the first heat exchanger (21) is close to the fresh air outlet (1012), the exhaust air channel (102) is provided with a third heat exchanger (23), the partition plate (11) has a backflow port, the backflow port communicates the air inlet side space of the second heat exchanger (22) with the air outlet side space of the third heat exchanger (23), the fresh air conditioner further comprises an outdoor heat exchanger (24) and an intermediate heat exchanger (25), a first heat exchange flow channel in the first heat exchanger (21), the third heat exchanger (23) and the intermediate heat exchanger (25) are connected in series to form a first flow path, a second heat exchange flow channel in the intermediate heat exchanger (25) and the second heat exchanger (22) are connected in series to form a second flow path, the first flow path and the second flow path are connected in parallel, the first end of the first flow path and the first end of the second flow path are connected in communication with the side of the outdoor heat exchanger (24) away from the exhaust port of a compressor (3), and the second end of the first flow path and the second end of the second flow path are capable of being connected in communication with the suction port of the compressor (3).

2. The fresh air conditioner according to claim 1, characterized in that, The first flow path further has a first throttling element (41) and a second throttling element (42) connected in series, the first throttling element (41) is between the outdoor heat exchanger (24) and the first heat exchanger (21), and the second throttling element (42) is between the first heat exchanger (21) and the third heat exchanger (23).

3. The fresh air conditioner according to claim 2, characterized in that, the second flow path further has a third throttling element (43) connected in series, the third throttling element (43) is between the intermediate heat exchanger (25) and the second heat exchanger (22).

4. The fresh air conditioner according to claim 1, characterized in that, The first flow path is further connected in series with a third shutoff valve (53) on the side of the intermediate heat exchanger (25) away from the third heat exchanger (23), and the second flow path is further connected in series with a second shutoff valve (52) and a first shutoff valve (51), wherein the second shutoff valve (52) is on the pipe section of the second flow path close to the outdoor heat exchanger (24), and the first shutoff valve (51) is on the pipe section of the second flow path close to the suction port of the compressor (3).

5. The fresh air conditioner according to any one of claims 1 to 4, characterized in that, A four-way reversing valve (6) is further included, a first port of the four-way reversing valve (6) is in communication with the discharge port of the compressor (3), a second port is in communication with the first end of the outdoor heat exchanger (24), a third port is in communication with the suction port of the compressor (3), and a fourth port is in communication with the second ends of the first flow path and the second flow path in parallel.

6. The fresh air conditioner according to claim 1, characterized in that, A fresh air inlet (1011) is provided with a fresh air damper (71), an exhaust air outlet (1021) is provided with an exhaust air damper (72), and a return air inlet is provided with a return air damper (73).

7. The fresh air conditioner according to claim 1, characterized in that, The fresh air passage (101) is further provided with a humidifying component (8) on the air outlet side of the first heat exchanger (21).

8. A control method of a fresh air conditioner according to any one of claims 1 to 7, characterized by, The method comprises the following steps: Obtaining the operation mode of the fresh air conditioner; According to the obtained operation mode, controlling the opening and closing of the fresh air inlet (1011), the exhaust air outlet (1021), and the return air inlet, and controlling the on-off of the first flow path and the second flow path.

9. The control method according to claim 8, wherein When the operation mode is the dehumidification mode, the fresh air inlet (1011), the exhaust air outlet (1021), and the return air inlet are all controlled to be opened, and the first flow path and the second flow path are both controlled to be through.

10. The control method according to claim 9, wherein When the first throttling element (41), the second throttling element (42), and the third throttling element (43) are included, the first throttling element (41), the second throttling element (42), and the third throttling element (43) are all controlled to be in the throttling state.

11. The control method according to claim 8, wherein When the operation mode is the dehumidification and heating mode, the fresh air inlet (1011) and the exhaust air outlet (1021) are controlled to be opened, the return air inlet is controlled to be closed, the first flow path is controlled to be through, and the second flow path is controlled to be shut off.

12. The control method according to claim 8, wherein When the fresh air conditioner further includes a four-way reversing valve (6) and the operation mode is the refrigeration mode, the four-way reversing valve (6) is controlled to be in the refrigeration state, the fresh air inlet (1011) and the exhaust air outlet (1021) are both controlled to be closed, the return air inlet is controlled to be opened, the second flow path is controlled to be through, and the first flow path is controlled to be shut off; or When the fresh air conditioner further comprises a four-way reversing valve (6) and the operation mode is the heating mode, the four-way reversing valve (6) is controlled to be in the heating state, the fresh air inlet (1011) and the exhaust air outlet (1021) are both controlled to be closed, the backflow port is controlled to be open, and the second flow path is controlled to be through and the first flow path is controlled to be blocked.

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