Heat exchanger, air conditioner and control method thereof

Abstract

The application provides a heat exchanger, an air conditioner and a control method thereof. The heat exchanger comprises an upper refrigerant branch and a lower refrigerant branch. The upper refrigerant branch has an upper liquid port and an upper gas port. The lower refrigerant branch has a lower liquid port and a lower gas port. The upper gas port and the upper liquid port are communicated with the upper port of the upper refrigerant branch through a first flow path switching valve. The lower refrigerant branch is communicated with the upper refrigerant branch at a first point. The lower liquid port is communicated with the first point through a second flow path switching valve. The lower gas port is communicated with the lower refrigerant branch. The two flow path switching valves are used to parallelly combine the upper gas pipe communicated with the upper gas port and the lower gas pipe communicated with the lower gas port into a total gas pipe when the heat exchanger is used as an evaporator. The liquid phase refrigerant formed after heat exchange is combined into the total gas pipe in a parallel way. The gas phase refrigerant discharged from the two refrigerant branches does not collide. The pressure loss caused by the combination of the refrigerants is small. The sufficient suction of the compressor in the air conditioner is effectively ensured. The heat exchange performance of the air conditioning system is further ensured.

Description

Technical Field

[0001] This invention belongs to the field of air conditioning technology, specifically relating to a heat exchanger, an air conditioner, and a control method thereof. Background Technology

[0002] The flow path length has a significant impact on the heat exchange efficiency of air conditioning heat exchangers. With the same air inlet conditions and flow rate, heat exchanger geometry, and piping arrangement, shortening the flow path length increases the temperature difference between the air and refrigerant, but decreases the overall heat transfer coefficient. When the indoor heat exchanger functions as an evaporator, the heat exchange initially increases and then decreases. There exists an optimal flow path length that maximizes the heat exchange. When the flow path length is greater than or less than the optimal length, the dominant factors for heat exchange are the temperature difference and the overall heat transfer coefficient, respectively. When the indoor heat exchanger functions as a condenser, the heat exchange decreases monotonically with decreasing flow path length, and the overall heat transfer coefficient remains the dominant factor limiting heat exchange. Therefore, to coordinate and simultaneously improve the efficiency of the cooling and heating cycles, it is necessary to optimize the flow path length of the heat exchanger in the heat pump system.

[0003] According to simulation analysis results from the EVAP-COND software developed by NIST, during cooling, given the same airflow and evaporator outlet superheat, the optimal flow path length differs at different evaporation temperatures. At low evaporation temperatures, a shorter flow path results in greater heat transfer, while at high evaporation temperatures, a longer flow path results in greater heat transfer. This means that the optimal flow path length for the evaporator differs between full-load and low-load operation of the air conditioner.

[0004] In order to at least partially overcome the aforementioned shortcomings of the prior art, a heat exchanger with a variable heat exchange flow path length is disclosed in the related art. However, when the heat exchanger is used as an evaporator, the refrigerant in the two parallel branches needs to be reversed and then flow out of the heat exchanger together. This reversed refrigerant has a countercurrent problem, resulting in a large pressure loss, which leads to insufficient air intake of the air conditioning system compressor, and thus a decrease in heat exchange performance. Summary of the Invention

[0005] Therefore, the present invention provides a heat exchanger, an air conditioner and a control method thereof, which can solve the technical problem in the prior art where, when a heat exchanger with a variable heat exchange flow path length is used as an evaporator, the refrigerant flows in opposite directions in the two branches converge, resulting in a large pressure loss, which leads to insufficient air intake of the air conditioning system compressor and thus a decrease in heat exchange performance.

[0006] To address the above problems, the present invention provides a heat exchanger comprising:

[0007] The heat exchanger comprises an upper refrigerant branch and a lower refrigerant branch. The upper refrigerant branch has an upper liquid port and an upper gas port, and the lower refrigerant branch has a lower liquid port and a lower gas port. The upper gas port and the upper liquid port are connected to the upper port of the upper refrigerant branch via a first flow path switching valve. The upper port and the lower port of the lower refrigerant branch are connected to a first point. The lower liquid port is connected to the first point via a second flow path switching valve. The lower gas port is connected to the lower port of the lower refrigerant branch. The first flow path switching valve and the second flow path switching valve are used together to ensure that when the heat exchanger is used as an evaporator, a portion of the refrigerant flowing in through the lower liquid port flows through the upper refrigerant branch and exits through the upper gas port, while the other portion flows through the lower refrigerant branch and exits through the lower gas port. The upper gas pipe connected to the upper gas port and the lower gas pipe connected to the lower gas port are parallel and merge into the main gas pipe.

[0008] In some embodiments, the first flow path switching valve and the second flow path switching valve are also used together to ensure that when the heat exchanger is used as a condenser, the refrigerant at the lower gas port flows sequentially through the lower refrigerant branch and the upper refrigerant branch before flowing out through the upper liquid port.

[0009] In some embodiments, the first flow path switching valve is a first electromagnetic three-way valve, wherein the first port of the first electromagnetic three-way valve is connected to the upper liquid port, the second port is connected to the upper port of the upper refrigerant branch, and the third port is connected to the upper gas port.

[0010] The second flow path switching valve is a first electromagnetic two-way valve.

[0011] In some embodiments, the first flow path switching valve includes:

[0012] The second electromagnetic two-way valve and the first one-way valve are connected in series in the pipeline between the upper liquid port and the upper port of the upper refrigerant branch. The pipeline between the second electromagnetic two-way valve and the upper port of the upper refrigerant branch is the first pipeline. The first one-way valve is connected in series in the pipeline between the upper gas port and the first pipeline. The unidirectional flow direction of the first one-way valve is the direction in which the refrigerant flows out of the upper gas port.

[0013] The second flow path switching valve is a second check valve, which is connected in series in the pipeline between the liquid outlet and the first point, and the unidirectional flow direction of the second check valve is the direction in which the refrigerant flows into the liquid outlet.

[0014] In some embodiments, the upper refrigerant branch and / or lower refrigerant branch are serpentine pipes.

[0015] The present invention also provides an air conditioner, including the heat exchanger described above, wherein the heat exchanger is an indoor heat exchanger.

[0016] The present invention also provides a control method for an air conditioner as described above, comprising:

[0017] Obtain the operating mode of the air conditioner;

[0018] According to the operating mode, the first flow path switching valve and / or the second flow path switching valve are controlled to switch the refrigerant flow direction.

[0019] In some implementations...

[0020] When the operating mode is heating mode, and the first flow path switching valve is a first solenoid three-way valve and the second flow path switching valve is a first solenoid two-way valve, the gaseous refrigerant is controlled to flow in from the lower gas port.

[0021] Controlling the first flow path switching valve and / or the second flow path switching valve to switch the refrigerant flow direction according to the operating mode includes:

[0022] Control the first solenoid two-way valve to disconnect, and connect the first port and the second port of the first solenoid three-way valve; or...

[0023] When the operating mode is heating mode, and the first flow path switching valve includes a second solenoid two-way valve and a first check valve, and the second flow path switching valve is a second check valve, the gaseous refrigerant is controlled to flow in from the lower gas port.

[0024] Controlling the first flow path switching valve and / or the second flow path switching valve to switch the refrigerant flow direction according to the operating mode includes:

[0025] Control the second solenoid two-way valve to connect.

[0026] In some implementations...

[0027] When the operating mode is cooling mode, and the first flow path switching valve includes a second solenoid two-way valve and a first check valve, and the second flow path switching valve is a second check valve, the liquid refrigerant is controlled to flow from the lower liquid port into the upper refrigerant branch and the lower refrigerant branch respectively.

[0028] Controlling the first flow path switching valve and / or the second flow path switching valve to switch the refrigerant flow direction according to the operating mode includes:

[0029] Control the second solenoid two-way valve to shut off.

[0030] In some implementations...

[0031] When the operating mode is cooling mode, and the first flow path switching valve is a first solenoid three-way valve and the second flow path switching valve is a first solenoid two-way valve, the cooling load of the heat exchanger is further determined.

[0032] When the heat exchanger is under high cooling load

[0033] The liquid refrigerant is controlled to flow from the lower liquid port into the upper refrigerant branch and the lower refrigerant branch respectively.

[0034] Controlling the first flow path switching valve and / or the second flow path switching valve to switch the refrigerant flow direction according to the operating mode includes:

[0035] Control the first solenoid two-way valve to connect, and connect the second port and the third port of the first solenoid three-way valve; or...

[0036] When the heat exchanger is under low cooling load

[0037] The liquid refrigerant is controlled to flow from the upper liquid port into the upper refrigerant branch.

[0038] Controlling the first flow path switching valve and / or the second flow path switching valve to switch the refrigerant flow direction according to the operating mode includes:

[0039] Control the first electromagnetic two-way valve to cut off, and connect the first port and the second port of the first electromagnetic three-way valve.

[0040] The present invention provides a heat exchanger, an air conditioner, and a control method thereof, which have the following beneficial effects:

[0041] When the heat exchanger is used as an evaporator (when the heat exchanger is an indoor heat exchanger, i.e., the air conditioner is operating in cooling mode), the refrigerant in the upper and lower refrigerant branches flows in parallel. At this time, the heat exchanger has a large heat exchange temperature difference and a low heat exchange coefficient, which makes the total heat exchange capacity at a high level under this condition and the heat exchange effect is high. At the same time, the gaseous refrigerant formed after heat exchange merges in the main gas pipe in a parallel manner. The gaseous refrigerant flowing out of the two refrigerant branches does not collide, and the pressure loss caused by the refrigerant merging is small. This effectively ensures that the compressor in the air conditioner draws in enough gas, further ensuring the heat exchange performance of the air conditioning system, and also effectively reducing the operating noise of the system.

[0042] The heat exchanger has a long heat exchange flow path between the inlet and outlet of the heat exchanger, a small heat exchange temperature difference, a high heat exchange coefficient, and a high total heat exchange capacity. Thus, by controlling the aforementioned flow path switching valve group, the heat exchanger in this invention can have a high total heat exchange capacity whether it is used as an evaporator or a condenser, thereby ensuring that the heat exchange performance of the air conditioner is better in both operating conditions.

[0043] When the heat exchanger is used as a condenser, the gaseous refrigerant in this invention flows through the heat exchanger from bottom to top. When the heat exchanger needs to be defrosted as a condenser, the high-temperature gaseous refrigerant is first guided to the lower region of the heat exchanger, thus making defrosting at the bottom of the heat exchanger more efficient. It should be noted that when the heat exchanger is used as an evaporator, when the evaporation temperature is too low, frost will form on the surface of the heat exchanger. At this time, the corresponding air conditioner can be controlled to operate in heating mode, and the heat exchanger will be used as a condenser. At this time, the high-temperature refrigerant can defrost the surface of the heat exchanger. After the upper part is defrosted, it will flow to the lower region under its own weight, making defrosting at the bottom of the heat exchanger more difficult (increasing the cooling capacity of the lower region). However, by guiding the high-temperature refrigerant to the lower region of the heat exchanger first, the defrosting of this region can be achieved efficiently.

[0044] The refrigerant flow path length can be switched by controlling the opening and closing of the first solenoid two-way valve and the first solenoid three-way valve. More importantly, the opening and closing of the first solenoid two-way valve and the first solenoid three-way valve can also switch the refrigerant flow path length between high-load operation and low-load operation of the compressor when the heat exchanger is used as an evaporator, ensuring that the total heat exchange is at a high level under both high and low load conditions.

[0045] Both the first and second check valves are pressure differential driven mechanical on / off valves. By selecting the unidirectional flow direction of the two valves, it is possible to match the refrigerant flow direction of the heat exchanger with different operating conditions of the air conditioner without the need for electrical signal control and in conjunction with the electrical control of a second solenoid two-way valve. The control is simple and the manufacturing cost is low. Attached Figure Description

[0046] 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.

[0047] 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.

[0048] Figure 1 This is a schematic diagram of the heat exchanger in the first embodiment of the present invention;

[0049] Figure 2for Figure 1 The diagram shows the refrigerant flow direction when the heat exchanger is used as an evaporator. The arrows in the diagram indicate the refrigerant flow direction, and the heat exchanger is operating at a high cooling load at this time.

[0050] Figure 3 for Figure 1 The diagram shows the refrigerant flow direction when the heat exchanger is used as an evaporator. The arrows in the diagram indicate the refrigerant flow direction, and the heat exchanger is operating at a low cooling load at this time.

[0051] Figure 4 for Figure 1 A schematic diagram of the refrigerant flow direction when the heat exchanger is used as a condenser. The arrows in the diagram indicate the refrigerant flow direction.

[0052] Figure 5 This is a schematic diagram of the heat exchanger in the second embodiment of the present invention;

[0053] Figure 6 for Figure 5 A schematic diagram of the refrigerant flow direction when the heat exchanger is used as an evaporator. The arrows in the diagram indicate the refrigerant flow direction.

[0054] Figure 7 for Figure 6 The diagram shows the refrigerant flow direction when the heat exchanger is used as a condenser. The arrows in the diagram indicate the refrigerant flow direction.

[0055] The reference numerals in the attached figures are as follows:

[0056] 1. Upper refrigerant branch; 11. Upper liquid inlet; 12. Upper gas inlet; 2. Lower refrigerant branch;

[0057] 21. Liquid outlet; 22. Gas outlet; 31. First solenoid three-way valve; 32. First solenoid two-way valve; 41. Second solenoid two-way valve; 42. First check valve; 43. Second check valve; 5. Heat exchange fins. Detailed Implementation

[0058] 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.

[0059] 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.

[0060] 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.

[0061] 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.

[0062] 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.

[0063] 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.

[0064] 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.

[0065] See also Figure 1 and Figure 7 As shown, according to an embodiment of the present invention, a heat exchanger is provided, comprising:

[0066] The upper refrigerant branch 1 and the lower refrigerant branch 2 are provided. The upper refrigerant branch has an upper liquid port 11 and an upper gas port 12, and the lower refrigerant branch 2 has a lower liquid port 21 and a lower gas port 22. The upper gas port 12 and the upper liquid port 11 are connected to the upper port of the upper refrigerant branch 1 through a first flow path switching valve. The upper port of the lower refrigerant branch 2 is connected to the lower port of the upper refrigerant branch 1 at a first point. The lower liquid port 21 is connected to the first point through a second flow path switching valve. The lower gas port 22 is connected to the lower port of the lower refrigerant branch 2. The first flow path switching valve... The switching valve and the second flow path switching valve work together when the heat exchanger is used as an evaporator, so that a portion of the refrigerant flowing into the lower liquid port 21 flows through the upper refrigerant branch 1 and out through the upper gas port 12, while the other portion flows through the lower refrigerant branch 2 and out through the lower gas port 22. The upper gas pipe (not shown in the figure) connected to the upper gas port 12 and the lower gas pipe (not shown in the figure) connected to the lower gas port 22 merge parallel to each other into the main gas pipe (not shown in the figure). That is, under this operating condition, the refrigerant in the upper refrigerant branch 1 and the lower refrigerant branch 2 flows in parallel. (See also...) Figure 1 and Figure 5As shown, the aforementioned upper liquid port 11, upper gas port 12, lower liquid port 21, and lower gas port 22 are all located on the same side of the heat exchanger body (not labeled in the figure), which makes the pipeline connection more convenient and the overall pipeline layout more reasonable and compact. It should be noted that, ideally, the upper and lower gas pipes should be strictly parallel when they merge. However, objectively, they only need to meet certain requirements in the parallelism direction, with the basic principle being to avoid excessive backlash between the two refrigerant branches. For example, the angle between the extended intersection of the pipe sections at the junction of the two branches in the assembled state should not exceed 10°.

[0067] In this technical solution, when the heat exchanger is used as an evaporator (when the heat exchanger is an indoor heat exchanger, i.e., the air conditioner is operating in cooling mode), the refrigerant in the upper refrigerant branch 1 and the lower refrigerant branch 2 flows in parallel. At this time, the heat exchanger has a large heat exchange temperature difference and a low heat exchange coefficient, which makes the total heat exchange under this condition relatively high and the heat exchange effect relatively high. At the same time, the gaseous refrigerant formed after heat exchange merges in the main gas pipe in a parallel manner. The gaseous refrigerant flowing out of the two refrigerant branches does not collide, and the pressure loss caused by the refrigerant merging is small, which effectively ensures that the compressor in the air conditioner draws in enough gas, further ensuring the heat exchange performance of the air conditioning system, and also effectively reducing the operating noise of the system.

[0068] In some embodiments, the first flow path switching valve and the second flow path switching valve are also used together to ensure that when the heat exchanger is used as a condenser, the refrigerant in the lower gas port 22 flows through the lower refrigerant branch 2 and the upper refrigerant branch 1 in sequence and then flows out through the upper liquid port 11. That is, under this operating condition, the refrigerant in the upper refrigerant branch 1 and the lower refrigerant branch 2 flows in series, resulting in a large heat exchange flow path length.

[0069] In this technical solution, the heat exchanger has a long heat exchange flow path between the inlet and outlet of the heat exchanger, a small heat exchange temperature difference, a high heat exchange coefficient, and a relatively high total heat exchange capacity. Thus, by controlling the aforementioned flow path switching valve group, the heat exchanger in this invention can have a high total heat exchange capacity whether it is used as an evaporator or a condenser, thereby ensuring that the heat exchange performance of the air conditioner is superior under both operating conditions.

[0070] Furthermore, when the heat exchanger is used as a condenser, the gaseous refrigerant in this invention flows through the heat exchanger from bottom to top. When the heat exchanger needs to be defrosted as a condenser, the high-temperature gaseous refrigerant is first guided to the lower region of the heat exchanger, thus making defrosting at the bottom of the heat exchanger more efficient. It should be noted that when the heat exchanger is operating as an evaporator, when the evaporation temperature is too low, frost will form on the surface of the heat exchanger. At this time, the corresponding air conditioner can be controlled to operate in heating mode, and the heat exchanger will be used as a condenser. At this time, the high-temperature refrigerant can defrost the surface of the heat exchanger. After the upper part is defrosted, it will flow to the lower region under its own weight, making defrosting at the bottom of the heat exchanger more difficult (increasing the cooling capacity of the lower region). However, in this invention, the high-temperature refrigerant is first guided to the lower region of the heat exchanger, which can efficiently achieve defrosting in this region.

[0071] Figures 1 to 4 A first embodiment of the heat exchanger of the present invention is shown:

[0072] In the first embodiment, the first flow path switching valve is a first electromagnetic three-way valve 31, the first port a of the first electromagnetic three-way valve 31 is connected to the liquid inlet 11, the second port b is connected to the upper port of the upper refrigerant branch 1, and the third port c is connected to the gas inlet 12; the second flow path switching valve is a first electromagnetic two-way valve 32.

[0073] In this technical solution, the refrigerant flow path length is switched by controlling the opening and closing of the first electromagnetic three-way valve 31 and the first electromagnetic two-way valve 32. More importantly, the opening and closing of the aforementioned first electromagnetic three-way valve 31 and the first electromagnetic two-way valve 32 can also switch the refrigerant flow path length between high-load operation and low-load operation of the compressor when the heat exchanger is used as an evaporator, ensuring that the total heat exchange is at a high level under both high and low load conditions.

[0074] Figures 5 to 7 A second embodiment of the heat exchanger of the present invention is shown:

[0075] In the second embodiment, the first flow path switching valve includes: a second electromagnetic two-way valve 41 and a first one-way valve 42. The second electromagnetic two-way valve 41 is connected in series in the pipeline between the upper liquid port 11 and the upper port of the upper refrigerant branch 1. The pipeline between the second electromagnetic two-way valve 41 and the upper port of the upper refrigerant branch 1 is the first pipeline. The first one-way valve 42 is connected in series in the pipeline between the upper gas port 12 and the first pipeline, and the one-way flow direction of the first one-way valve 42 is the direction in which the refrigerant flows out of the upper gas port 12. The second flow path switching valve is a second one-way valve 43. The second one-way valve 43 is connected in series in the pipeline between the lower liquid port 21 and the first point, and the one-way flow direction of the second one-way valve 43 is the direction in which the refrigerant flows into the lower liquid port 21.

[0076] In this technical solution, the first one-way valve 42 and the second one-way valve 43 are both mechanical on-off valves driven by differential pressure. By selecting the one-way conduction direction of the two valves, it is possible to match the refrigerant flow direction of the heat exchanger with different operating conditions of the air conditioner without the need for electrical signal control and in combination with the electrical control of a second electromagnetic two-way valve 41. The control is simple and the manufacturing cost is low.

[0077] In some embodiments, the upper refrigerant branch 1 and / or the lower refrigerant branch 2 are serpentine tubes to ensure a longer refrigerant flow path length within a limited space. It is understood that both the upper refrigerant branch 1 and the lower refrigerant branch 2 are interspersed on multiple parallel, spaced-apart heat exchange fins 5.

[0078] According to an embodiment of the present invention, an air conditioner is also provided, including the heat exchanger described above, which can be used as an outdoor heat exchanger or an indoor heat exchanger of the air conditioner.

[0079] Taking the heat exchanger as an indoor heat exchanger as an example, according to an embodiment of the present invention, a control method for an air conditioner as described above is also provided, comprising:

[0080] The operating mode of the air conditioner is obtained, including cooling mode and heating mode;

[0081] According to the operating mode, the first flow path switching valve and / or the second flow path switching valve are controlled to switch the refrigerant flow direction.

[0082] It is understandable that by controlling the operation of the first flow path switching valve and / or the second flow path switching valve for the corresponding operating mode, the refrigerant flow direction can be switched to the flow direction corresponding to the operating mode. This ensures that the refrigerant flow path length is at an optimal length in both cooling and heating modes, thereby ensuring that the heat exchanger has a high total heat exchange volume in the corresponding operating mode.

[0083] Specifically, regarding the aforementioned first embodiment, when the operating mode is heating mode, and the first flow path switching valve is a first electromagnetic three-way valve 31 and the second flow path switching valve is a first electromagnetic two-way valve 32, controlling the gaseous refrigerant to flow in from the lower gas port 22, and controlling the first flow path switching valve and / or the second flow path switching valve to switch the refrigerant flow direction according to the operating mode includes: controlling the first electromagnetic two-way valve 32 to disconnect, and connecting the first port a and the second port b of the first electromagnetic three-way valve 31; at this time, see Figure 4As shown, the third port c of the first electromagnetic three-way valve 31 is connected to the second port b, while the two ports a and b of the first electromagnetic two-way valve 32 are not connected. The gaseous refrigerant flowing from the main gas pipe enters the lower refrigerant branch 2 of the heat exchanger through the lower gas port 22. After heat exchange, it enters the upper refrigerant branch 1 and finally flows to the main liquid pipe through the upper liquid port 11. At this time, the heat exchange temperature difference is small, the heat exchange coefficient is high, and the total heat exchange capacity of the heat exchanger is high.

[0084] Alternatively, in the aforementioned second embodiment, when the operating mode is heating mode, and the first flow path switching valve includes a second solenoid two-way valve 41 and a first one-way valve 42, and the second flow path switching valve is a second one-way valve 43, controlling the gaseous refrigerant to flow in from the lower gas port 22, and controlling the first flow path switching valve and / or the second flow path switching valve to switch the refrigerant flow direction according to the operating mode includes: controlling the second solenoid two-way valve 41 to connect. In this case, see... Figure 7 As shown, the two ports a and b of the second electromagnetic two-way valve 41 are cut off. The gaseous refrigerant flowing from the main gas pipe enters the lower refrigerant branch 2 of the heat exchanger through the lower gas port 22. After heat exchange, it enters the upper refrigerant branch 1 and finally flows to the main liquid pipe through the upper liquid port 11. Since there is a pressure drop of the refrigerant in the heat exchanger (lower refrigerant branch 2), the pressure at port f of the second one-way valve 43 is higher than that at port e. Therefore, during heating operation, the second one-way valve 43 does not conduct. At the same time, the pressure at port d of the first one-way valve 42 is lower than that at port c, so the first one-way valve 42 also does not conduct.

[0085] Furthermore, regarding the second embodiment, when the operating mode is the cooling mode, and the first flow path switching valve includes a second solenoid two-way valve 41 and a first one-way valve 42, and the second flow path switching valve is a second one-way valve 43, the liquid refrigerant is controlled to flow from the lower liquid port 21 into the upper refrigerant branch 1 and the lower refrigerant branch 2 respectively. Controlling the first flow path switching valve and / or the second flow path switching valve to switch the refrigerant flow direction according to the operating mode includes: controlling the second solenoid two-way valve 41 to cut off the flow. At this time, the corresponding reference is... Figure 6 As shown, the two ports a and b of the second electromagnetic two-way valve 41 are cut off and not connected. A portion of the liquid refrigerant flowing from the main liquid pipe enters the upper refrigerant branch 1 for heat exchange, and then flows to the upper gas port 12 through the channel between port d and port c of the first one-way valve 42, and then flows to the main gas pipe. Another portion of the liquid refrigerant enters the lower refrigerant branch 2 for heat exchange, and then flows to the main gas pipe through the lower gas port 22. At this time, the heat exchanger has a large heat exchange temperature difference and a low heat exchange coefficient, and the heat exchanger has a high total heat exchange capacity.

[0086] Regarding the first embodiment, when the operating mode is cooling mode, and the first flow path switching valve is the first solenoid three-way valve 31 and the second flow path switching valve is the first solenoid two-way valve 32, the cooling load of the heat exchanger is further determined. Specifically,

[0087] When the heat exchanger is under high cooling load, that is, when the heat exchanger is used as an evaporator and at a low evaporation temperature, see [reference needed]. Figure 2 As shown, the liquid refrigerant is controlled to flow into the upper refrigerant branch 1 and the lower refrigerant branch 2 respectively from the lower liquid port 21. The control of the first flow path switching valve and / or the second flow path switching valve to switch the refrigerant flow direction according to the operating mode includes: controlling the first electromagnetic two-way valve 32 to connect and the second port b and the third port c of the first electromagnetic three-way valve 31 to connect. At this time, a part of the liquid refrigerant flowing from the main liquid pipe enters the upper refrigerant branch 1 for heat exchange, and then flows to the upper gas port 12 through the ports b and c of the first electromagnetic three-way valve 31, and then flows to the main gas pipe. The other part of the liquid refrigerant enters the lower refrigerant branch 2, and after heat exchange, flows to the main gas pipe through the lower gas port 22. At this time, the heat exchanger has a large heat exchange temperature difference, a low heat exchange coefficient, and a high total heat exchange.

[0088] Alternatively, when the heat exchanger is under low cooling load, that is, when the heat exchanger is used as an evaporator at a high evaporation temperature, see [reference needed]. Figure 3 As shown, the control of the liquid refrigerant flowing from the upper liquid port 11 into the upper refrigerant branch 1, and the control of the first flow path switching valve and / or the second flow path switching valve to switch the refrigerant flow direction according to the operating mode includes: controlling the first electromagnetic two-way valve 32 to cut off, and connecting the first port a and the second port b of the first electromagnetic three-way valve 31. The liquid refrigerant flowing from the main liquid pipe passes through the upper liquid port 11, passes through the upper refrigerant branch 1 for heat exchange, and then passes through the lower refrigerant branch 2. After heat exchange, it flows from the lower gas port 22 to the main gas pipe. At this time, the heat exchanger has a small heat exchange temperature difference, a high heat exchange coefficient, and a high total heat exchange.

[0089] During cooling operation, generally speaking, if the air conditioner compressor frequency is less than 50% of the rated frequency, it is considered to be operating under low cooling load; otherwise, it is operating under high cooling load.

[0090] 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 heat exchanger, characterized in that, include: The upper refrigerant branch (1) and the lower refrigerant branch (2) are provided. The upper refrigerant branch has an upper liquid port (11) and an upper gas port (12). The lower refrigerant branch (2) has a lower liquid port (21) and a lower gas port (22). The upper gas port (12) and the upper liquid port (11) are connected to the upper port of the upper refrigerant branch (1) through a first flow path switching valve. The upper port of the lower refrigerant branch (2) is connected to the lower port of the upper refrigerant branch (1) at a first point. The lower liquid port (21) is connected to the first point through a second flow path switching valve. The lower gas port (22) is connected to the lower port of the lower refrigerant branch (2). The first flow path switching valve is connected to the second flow path switching valve. The flow path switching valve is used together to ensure that when the heat exchanger is used as an evaporator, a portion of the refrigerant flowing into the lower liquid port (21) flows through the upper refrigerant branch (1) and out through the upper gas port (12), while the other portion flows through the lower refrigerant branch (2) and out through the lower gas port (22). The upper gas pipe connected to the upper gas port (12) and the lower gas pipe connected to the lower gas port (22) are parallel and merge into the main gas pipe. The first flow path switching valve and the second flow path switching valve are also used together to ensure that when the heat exchanger is used as a condenser, the refrigerant from the lower gas port (22) flows through the lower refrigerant branch (2) and the upper refrigerant branch (1) in sequence and then out through the upper liquid port (11). The first flow path switching valve includes: a second electromagnetic two-way valve (41) and a first one-way valve (42). The second electromagnetic two-way valve (41) is connected in series in the pipeline between the upper liquid port (11) and the upper port of the upper refrigerant branch (1). The pipeline between the second electromagnetic two-way valve (41) and the upper port of the upper refrigerant branch (1) is the first pipeline. The first one-way valve (42) is connected in series in the pipeline between the upper gas port (12) and the first pipeline. The one-way direction of the first one-way valve (42) is the direction in which the refrigerant flows out of the upper gas port (12). The second flow path switching valve is a second one-way valve (43). The second one-way valve (43) is connected in series in the pipeline between the lower liquid port (21) and the first point. The one-way direction of the second one-way valve (43) is the direction in which the refrigerant flows into the lower liquid port (21).

2. The heat exchanger according to claim 1, characterized in that, The upper refrigerant branch (1) and / or the lower refrigerant branch (2) are serpentine pipes.

3. An air conditioner, characterized in that, The heat exchanger includes any one of claims 1 to 2, wherein the heat exchanger is an indoor heat exchanger.

4. A control method for an air conditioner as described in claim 3, characterized in that, include: Obtain the operating mode of the air conditioner; According to the operating mode, the first flow path switching valve and / or the second flow path switching valve are controlled to switch the refrigerant flow direction.

5. The control method according to claim 4, characterized in that, When the operating mode is heating mode, the gaseous refrigerant is controlled to flow in from the lower gas port (22). Controlling the first flow path switching valve and / or the second flow path switching valve to switch the refrigerant flow direction according to the operating mode includes: Control the second electromagnetic two-way valve (41) to connect.

6. The control method according to claim 4, characterized in that, When the operating mode is cooling mode, the liquid refrigerant is controlled to flow from the lower liquid port (21) into the upper refrigerant branch (1) and the lower refrigerant branch (2) respectively. Controlling the first flow path switching valve and / or the second flow path switching valve to switch the refrigerant flow direction according to the operating mode includes: Control the second solenoid two-way valve (41) to shut off.

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