Outdoor heat exchanger and air conditioner

Abstract

The outdoor heat exchanger comprises a heat exchanger body, the heat exchanger body is provided with a heat exchange flow path, the heat exchange flow path is provided with a first main inlet and outlet and a second main inlet and outlet and comprises a first flow path, a second flow path and a third flow path, and the first end communicates with the first main inlet and outlet; the fifth end is communicated with the second main inlet / outlet; the gas-liquid separator is provided with a gas outlet, a first inlet and outlet and a second inlet and outlet, the second end and the third end are communicated with the first inlet and outlet, the second inlet and outlet is communicated with the sixth end, and the gas outlet is communicated with the fourth end and the first end; the first control valve is connected in series among the second end, the third end and the first inlet and outlet, and the second control valve is connected in series between the first end and the fourth end. According to the outdoor heat exchanger, the switching effect of different numbers of flow paths when the outdoor heat exchanger is in the refrigerating mode and the heating mode is achieved, so that the performance of the outdoor heat exchanger under different working conditions is improved.

Description

Outdoor heat exchanger and air conditioner Technical Field

[0001] This invention relates to the field of air handling equipment technology, and in particular to an outdoor heat exchanger and an air conditioner. Background Technology

[0002] Numerous studies have shown that outdoor heat exchangers, when used as condensers, exhibit higher heat transfer coefficients and better performance with fewer branch lines, while when used as evaporators, they show lower pressure losses and better performance with more branch lines. Therefore, the optimal flow path for an outdoor heat exchanger often differs between its cooling mode (condenser) and heating mode (evaporator). However, in current technologies, the flow path design process for outdoor heat exchangers typically involves separately determining the optimal number of branch lines for cooling and heating modes, then using a compromise number of branch lines as the final design. While this ensures basic heat transfer performance meets requirements under any given operating condition, it fails to achieve optimal performance under different conditions. Summary of the Invention

[0003] This invention aims to at least solve one of the technical problems existing in the prior art. To this end, this invention proposes an outdoor heat exchanger that switches between different numbers of flow paths in cooling and heating modes, thereby improving the performance of the outdoor heat exchanger under different operating conditions and increasing its overall efficiency.

[0004] The present invention also proposes an air conditioner, which includes the above-mentioned outdoor heat exchanger.

[0005] An outdoor heat exchanger according to an embodiment of the present invention, used in an air conditioner, includes: a heat exchanger body having a plurality of heat exchange tubes, the heat exchanger body having a heat exchange flow path, the heat exchange flow path having a first total inlet and outlet and a second total inlet and outlet, and including a first flow path, a second flow path and a third flow path, the two ends of the first flow path along its length being a first end and a second end, the two ends of the second flow path along its length being a third end and a fourth end, the two ends of the third flow path along its length being a fifth end and a sixth end, the first end being connected to the first total inlet and outlet, and the fifth end being connected to the second total inlet and outlet; a gas-liquid separator having a gas outlet, a first inlet and outlet and a second inlet and outlet, the second end, the third end and the first inlet and outlet being connected, the second inlet and outlet being connected to the sixth end, the gas outlet being connected to the fourth end and the first end; a first control valve and a second control valve, the first control valve being connected in series between the second end, the third end and the first inlet and outlet, and the second control valve being connected in series between the first end and the fourth end.

[0006] According to an embodiment of the present invention, an outdoor heat exchanger has multiple heat exchange tubes on its body and a heat exchange flow path. The heat exchange flow path has a first main inlet and a second main inlet and includes a first flow path, a second flow path, and a third flow path. The two ends of the first flow path along its length are a first end and a second end, the two ends of the second flow path along its length are a third end and a fourth end, and the two ends of the third flow path along its length are a fifth end and a sixth end. The first end is connected to the first main inlet and the fifth end is connected to the second main inlet and the second flow path. A gas-liquid separator has a gas outlet, a first inlet and a second inlet and a second inlet and a third end. The second and third ends are connected to the first inlet and the second inlet and the sixth end. The gas outlet is connected to the fourth end and the first end. This allows the refrigerant flowing out of the first inlet and the third inlet to exchange heat in the subsequent heat exchange tubes, thereby reducing the inlet dryness of the refrigerant in the subsequent heat exchange tubes, reducing the deterioration of evaporative heat transfer caused by excessive gaseous refrigerant, and reducing the flow resistance of the subsequent heat exchange tubes. This effectively improves the phenomenon of decreased heat exchange performance caused by excessive gaseous refrigerant when the outdoor heat exchanger is used as an evaporator, and improves heat exchange efficiency.

[0007] Meanwhile, by connecting the first control valve in series between the second and third ends and the first inlet and outlet, and connecting the second control valve in series between the first and fourth ends, the flow path of the refrigerant in the heat exchange flow path is diversified and flexible, thereby realizing the switching effect of different numbers of flow paths in the outdoor heat exchanger in cooling mode and heating mode, so as to improve the performance of the outdoor heat exchanger under different operating conditions and improve the overall efficiency of the outdoor heat exchanger.

[0008] In some embodiments of the present invention, the first control valve is a solenoid valve; and / or, the second control valve is a check valve, which only allows the flowing medium to flow from the other end of the second flow path to the other end of the first flow path.

[0009] In some embodiments of the present invention, a distributor is further included, wherein one end of the first flow path, one end of the second flow path, and the first inlet / outlet are connected via the distributor.

[0010] In some embodiments of the present invention, the first flow path is a plurality of those arranged in parallel.

[0011] In some embodiments of the present invention, a plurality of heat exchange tubes of the first flow path are arranged in the height direction of the outdoor heat exchanger.

[0012] In some embodiments of the present invention, there are two first flow paths.

[0013] In some embodiments of the present invention, the invention further includes: a first manifold, which is connected to the gas outlet and the fourth end respectively; a second manifold, which is connected to the first manifold, the first end and the first main inlet / outlet respectively; and a second control valve connected in series between the first manifold and the second manifold.

[0014] In some embodiments of the present invention, the gas-liquid separator includes: a housing, the gas outlet, the first inlet and outlet and the second inlet and outlet are disposed on the housing, the inner diameter of the housing is at least 40 mm; and / or, the axial dimension of the inner cavity of the housing is at least 100 mm.

[0015] In some embodiments of the present invention, the gas-liquid separator further includes: a first pipeline, one end of which is connected to the gas outlet, and the other end of which extends into the gas-liquid separator or is flush with the outer end face of the gas-liquid separator.

[0016] In some embodiments of the present invention, one end of the first pipeline connected to the gas outlet extends into the gas-liquid separator, and the maximum length of the first pipeline extending into the gas-liquid separator is 30 mm.

[0017] In some embodiments of the present invention, the gas outlet and the first inlet / outlet are respectively located at the two end faces in the axial direction of the gas-liquid separator, and the second inlet / outlet is located on the side wall of the gas-liquid separator.

[0018] In some embodiments of the present invention, the heat exchange tubes of the first flow path, the heat exchange tubes of the second flow path, and the heat exchange tubes of the third flow path are arranged sequentially along the height direction of the outdoor heat exchanger.

[0019] An air conditioner according to an embodiment of the present invention includes the outdoor heat exchanger described above.

[0020] According to an embodiment of the present invention, an outdoor heat exchanger is provided. A first control valve is connected in series between the second and third ends and the first inlet / outlet, and a second control valve is connected in series between the first and fourth ends. This allows for diverse and flexible flow paths of the refrigerant within the heat exchange flow path, enabling the outdoor heat exchanger to switch between different numbers of flow paths in cooling and heating modes. This improves the performance of the outdoor heat exchanger under different operating conditions and enhances the overall efficiency of the air conditioner. Simultaneously, a gas-liquid separator is provided with a gas outlet, a first inlet / outlet, and a second inlet / outlet. The second and third ends are connected to the first inlet / outlet, the second inlet / outlet is connected to the sixth end, and the gas outlet is connected to the fourth and first ends. This allows the refrigerant flowing out of the first inlet / outlet to exchange heat in subsequent heat exchange tubes, thereby reducing the inlet dryness of the refrigerant in the subsequent heat exchange tubes. This reduces the deterioration of evaporative heat transfer caused by excessive gaseous refrigerant and lowers the flow resistance of the subsequent heat exchange tubes. This effectively improves the performance degradation of the outdoor heat exchanger when it acts as an evaporator due to excessive gaseous refrigerant, thus improving the heat exchange efficiency of the air conditioner.

[0021] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0022] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0023] Figure 1 is a schematic diagram of the structure of an outdoor heat exchanger according to an embodiment of the present invention;

[0024] Figure 2 is a flow path diagram of an outdoor heat exchanger in heating mode according to an embodiment of the present invention;

[0025] Figure 3 is a flow path diagram of the outdoor heat exchanger in cooling mode according to an embodiment of the present invention;

[0026] Figure 4 is a front view of a gas-liquid separator according to an embodiment of the present invention;

[0027] Figure 5 is a calculation flow diagram of the gas bypass evaporator model of the outdoor heat exchanger according to an embodiment of the present invention;

[0028] Figure 6 is a genetic algorithm calculation flow of an outdoor heat exchanger according to an embodiment of the present invention;

[0029] Figure 7 is an internal streamline diagram of a gas-liquid separator according to an embodiment of the present invention, wherein there is one second inlet and outlet;

[0030] Figure 8 is an internal streamline diagram of a gas-liquid separator according to an embodiment of the present invention, and there are two second inlets and outlets.

[0031] Figure label:

[0032] 100. Outdoor heat exchanger;

[0033] 1. Heat exchanger body; 11. First flow path; 111. First end; 112. Second end; 12. Second flow path; 121. Third end; 122. Fourth end; 13. Third flow path; 131. Fifth end; 132. Sixth end; 14. First main inlet / outlet; 15. Second main inlet / outlet; 16. Heat exchanger tube;

[0034] 2. Gas-liquid separator; 21. Shell; 221. Gas outlet; 222. First inlet / outlet; 223. Second inlet / outlet; 22. First pipeline; 23. Second pipeline; 24. Third pipeline;

[0035] 3. First control valve;

[0036] 4. Second control valve;

[0037] 5. Distributor;

[0038] 6. First manifold;

[0039] 7. Second manifold. Detailed Implementation

[0040] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0041] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing the invention and simplifying the description, and 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 of the invention. Furthermore, features defined with "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0042] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0043] An outdoor heat exchanger 100 according to an embodiment of the present invention will now be described with reference to the accompanying drawings.

[0044] As shown in Figures 1-3, the outdoor heat exchanger 100 according to an embodiment of the present invention is used in an air conditioner. The outdoor heat exchanger 100 includes a heat exchanger body 1, a gas-liquid separator 2, a first control valve 3, and a second control valve 4.

[0045] The heat exchanger body 1 has multiple heat exchange tubes 16 and a heat exchange flow path. The heat exchange flow path has a first total inlet / outlet 14 and a second total inlet / outlet 15, and includes a first flow path 11, a second flow path 12, and a third flow path 13. Thus, the refrigerant enters the heat exchange flow path from one of the first total inlet / outlet 14 and the second total inlet / outlet 15, exchanges heat with the first flow path 11, the second flow path 12, and the third flow path 13, and then flows out from the other, thereby satisfying the requirements of the outdoor heat exchanger 100 acting as a condenser in cooling mode and as an evaporator in heating mode.

[0046] The first flow path 11 has two ends in the length direction, namely the first end 111 and the second end 112. The second flow path 12 has two ends in the length direction, namely the third end 121 and the fourth end 122. The third flow path 13 has two ends in the length direction, namely the fifth end 131 and the sixth end 132. The first end 111 is connected to the first total inlet / outlet 14, and the fifth end 131 is connected to the second total inlet / outlet 15. The gas-liquid separator 2 has a gas outlet 221, a first inlet / outlet 222 and a second inlet / outlet 223. The second end 112, the third end 121 and the first inlet / outlet 222 are connected. The second inlet / outlet 223 is connected to the sixth end 132. The gas outlet 221 is connected to the fourth end 122 and the first end 111. The first control valve 3 is connected in series between the second end 112, the third end 121 and the first inlet / outlet 222. The second control valve 4 is connected in series between the first end 111 and the fourth end 122.

[0047] Therefore, by controlling the connection and disconnection between the second end 112 and the third end 121 and the first inlet and outlet 222 through the first control valve 3, and by controlling the connection and disconnection between the first end 111 and the fourth end 122 through the second control valve 4, the flow path of the refrigerant in the heat exchange flow path has diversity and flexibility, thereby realizing the switching effect of different numbers of flow paths of the outdoor heat exchanger 100 in cooling mode and heating mode, so that the performance of the outdoor heat exchanger 100 under different operating conditions is improved, and the overall efficiency of the outdoor heat exchanger 100 is improved.

[0048] Meanwhile, when the outdoor heat exchanger 100 is used as an evaporator, the refrigerant enters the separation space of the gas-liquid separator 2 through the second inlet and outlet 223. Utilizing centrifugal force, the liquid refrigerant, due to its higher density, is thrown towards the wall of the shell 21 of the gas-liquid separator 2 and flows down the wall, exiting from the first inlet and outlet 222. The gaseous refrigerant, due to its lower density, accumulates in the central area and rises, exiting from the gas outlet 221. This effectively separates the gas-liquid mixture, allowing the refrigerant exiting from the first inlet and outlet 222 to exchange heat in the subsequent heat exchange tube 16. This reduces the inlet dryness of the refrigerant in the subsequent heat exchange tube 16, reduces the deterioration of evaporative heat transfer caused by excessive gaseous refrigerant, and reduces the flow resistance of the subsequent heat exchange tube 16. Consequently, this effectively improves the phenomenon of decreased heat exchange performance of the outdoor heat exchanger 100 when it is used as an evaporator due to excessive gaseous refrigerant, thereby improving heat exchange efficiency.

[0049] Specifically, when the outdoor heat exchanger 100 is used as an evaporator, the first control valve 3 is controlled to connect the second end 112 and the third end 121 with the first inlet and outlet 222, and the second control valve 4 is controlled to disconnect the connection between the first flow path 11 and the second flow path 12. Thus, the refrigerant enters the heat exchanger body 1 through the second main inlet / outlet 15 and flows into the third heat exchanger through the fifth end 131 for heat exchange. After heat exchange, the refrigerant flows into the gas-liquid separator 2 through the sixth end 132 and the second inlet / outlet 223 of the third heat exchanger. After separation by the gas-liquid separator 2, the gaseous refrigerant flows out from the gas outlet 221, and the liquid refrigerant flows from the first inlet / outlet 222 through the first control valve 3 to the second end 112 of the first heat exchange flow path and the third end 121 of the second heat exchange flow path. After merging with the gaseous refrigerant flowing out from the first end 111 of the first heat exchange flow path and the fourth end 122 of the second heat exchange flow path and the gas outlet 221, the liquid refrigerant flows out from the first main inlet / outlet 14.

[0050] Therefore, after the refrigerant flows into the third heat exchanger for heat exchange, it passes through the gas-liquid separator 2 to separate the gaseous and liquid phase refrigerant. This allows the refrigerant flowing out of the first inlet / outlet 222 to exchange heat in the parallel first and second heat exchange paths, reducing the dryness of the refrigerant in the second section of the first and third ends 121 of the second heat exchange paths. This reduces the deterioration of evaporative heat transfer caused by excessive gaseous refrigerant and lowers the flow resistance of the first and second heat exchange paths, thereby improving heat exchange efficiency. Simultaneously, when the outdoor heat exchanger 100 is used as an evaporator in heating mode, the reduction in the logarithmic mean temperature difference caused by pressure loss is the dominant factor affecting heat exchanger performance. By connecting the first and second heat exchange paths in parallel, the refrigerant flows through more branches, avoiding the pressure loss problems caused by excessive refrigerant flow and excessively long flow paths. This reduces the pressure drop of the refrigerant circulation, increases the temperature difference with the air, improves the heat exchange efficiency of the outdoor heat exchanger 100, and thus improves the heating efficiency of the air conditioner using this outdoor heat exchanger 100.

[0051] When the outdoor heat exchanger 100 is used as a condenser, the first control valve 3 is controlled to disconnect the connection between the second end 112 and the third end 121 and the first inlet and outlet 222, and the second control valve 4 is controlled to connect the first flow path 11 and the second flow path 12 and only allow the flowing medium to flow from the other end of the second flow path 12 to the other end of the first flow path 11. Thus, after the refrigerant enters the heat exchanger body 1 through the first main inlet / outlet 14, it flows to the first end 111 of the first heat exchange flow path and exchanges heat with the first heat exchange flow path. Then, the refrigerant flows from the second end 112 of the first heat exchange flow path to the third end 121 of the second heat exchange flow path and exchanges heat with the second heat exchange flow path. Finally, the refrigerant flows from the fourth end 122 of the second heat exchange flow path through the gas outlet 221 and the second inlet / outlet 223 to the sixth end 132 of the third heat exchange flow path. At this time, the gas-liquid separator 2, as a straight pipe, does not perform gas-liquid separation. After exchanging heat in the third heat exchange flow path, the refrigerant flows from the fifth end 131 of the third heat exchange flow path to the second main inlet / outlet 15 and then flows out of the heat exchanger body 1.

[0052] Therefore, when the outdoor heat exchanger 100 is used as a condenser in cooling mode, the flow rate is the dominant factor affecting the heat transfer coefficient. The refrigerant flows sequentially through the first flow path 11, the second flow path 12, and the third flow path 13, reducing the number of flow paths and improving heat exchanger performance. Simultaneously, fewer flow paths and a faster flow rate result in a larger heat transfer coefficient, improving the heat exchange effect of the refrigerant in superheated and dry areas, thereby increasing the cooling efficiency of the air conditioner using this outdoor heat exchanger 100.

[0053] According to an embodiment of the present invention, an outdoor heat exchanger 100 has a heat exchanger body 1 with a plurality of heat exchange tubes 16. The heat exchanger body 1 has a heat exchange flow path, which has a first total inlet / outlet 14 and a second total inlet / outlet 15 and includes a first flow path 11, a second flow path 12 and a third flow path 13. The two ends of the first flow path 11 along its length are a first end 111 and a second end 112, the two ends of the second flow path 12 along its length are a third end 121 and a fourth end 122, and the two ends of the third flow path 13 along its length are a fifth end 131 and a sixth end 132. The first end 111 is connected to the first total inlet / outlet 14, and the fifth end 131 is connected to the second total inlet / outlet 15. A gas-liquid separator is used for the connection. 2 has a gas outlet 221, a first inlet / outlet 222, and a second inlet / outlet 223. The second end 112, the third end 121, and the first inlet / outlet 222 are connected. The second inlet / outlet 223 is connected to the sixth end 132. The gas outlet 221 is connected to the fourth end 122 and the first end 111, so that the refrigerant flowing out of the first inlet / outlet 222 can exchange heat in the subsequent heat exchange tube 16, thereby reducing the inlet dryness of the refrigerant in the subsequent heat exchange tube 16, reducing the deterioration of evaporative heat transfer caused by excessive gaseous refrigerant, and reducing the flow resistance of the subsequent heat exchange tube 16. This effectively improves the phenomenon that the outdoor heat exchanger 100 has a decreased heat exchange performance due to excessive gaseous refrigerant when it is used as an evaporator, and improves the heat exchange efficiency.

[0054] Meanwhile, by connecting the first control valve 3 in series between the second end 112, the third end 121 and the first inlet / outlet 222, and by connecting the second control valve 4 in series between the first end 111 and the fourth end 122, the flow path of the refrigerant in the heat exchange flow path is diversified and flexible, thereby realizing the switching effect of different numbers of flow paths of the outdoor heat exchanger 100 in cooling mode and heating mode, so that the performance of the outdoor heat exchanger 100 under different operating conditions is improved and the overall efficiency of the outdoor heat exchanger 100 is improved.

[0055] In some embodiments of the present invention, as shown in Figures 1-3, the first control valve 3 is a solenoid valve. It is understood that because the solenoid valve can quickly and accurately control the opening and closing of the valve, it precisely controls the connection between the second end 112 and the third end 121 and the first inlet / outlet 222 when the outdoor heat exchanger 100 is used as an evaporator, and precisely controls the disconnection between the second end 112 and the third end 121 and the first inlet / outlet 222 when the outdoor heat exchanger 100 is used as a condenser, thereby improving the reliability of the outdoor heat exchanger 100.

[0056] In some embodiments of the present invention, as shown in Figures 1-3, the second control valve 4 is a one-way valve, which only allows the flowing medium to flow from the other end of the second flow path 12 to the other end of the first flow path 11. It is understood that when the outdoor heat exchanger 100 functions as a condenser, the second control valve 4 needs to connect the first flow path 11 and the second flow path 12, allowing the flowing medium to flow only from the other end of the second flow path 12 to the other end of the first flow path 11. When the outdoor heat exchanger 100 functions as an evaporator, the connection between the second flow path 12 and the first flow path 11 is disconnected. Therefore, making the second control valve 4 a one-way valve can meet the above requirements and reduce costs.

[0057] In some embodiments of the present invention, as shown in Figures 1-3, the outdoor heat exchanger 100 further includes a distributor 5. One end of the first flow path 11, one end of the second flow path 12, and the first inlet / outlet 222 are connected via the distributor 5. It is understood that when the outdoor heat exchanger 100 functions as an evaporator, the liquid refrigerant flows from the first inlet / outlet 222 to the distributor 5, where it is evenly distributed to one end of the first flow path 11 and one end of the second flow path 12. When the outdoor heat exchanger 100 functions as a condenser, the refrigerant flows from the second end 112 of the first heat exchange flow path to the distributor 5, and from the distributor 5 to the fourth end 122 of the second heat exchange flow path. Thus, the distributor 5 facilitates smoother refrigerant flow, reduces flow resistance and pressure drop, thereby improving heat exchange efficiency.

[0058] In some embodiments of the present invention, as shown in Figures 1-3, the first flow path 11 consists of multiple paths arranged in parallel.

[0059] Understandably, the parallel arrangement of multiple flow paths 11 increases the heat exchange efficiency of the outdoor heat exchanger 100 in heating mode. However, when the outdoor heat exchanger 100 is used as a condenser in cooling mode, the flow velocity becomes the dominant factor affecting the heat exchanger performance. Therefore, by setting multiple parallel flow paths connected to the first total inlet / outlet 14 as the first flow path 11, the refrigerant flow velocity entering the heat exchanger body 1 from the first total inlet / outlet 14 is increased, ensuring the refrigerant flow velocity in the second flow path 12 and the third flow path 13, thereby guaranteeing heat exchange efficiency. Simultaneously, the second flow path 12 and the third flow path 13, as confluence sections, increase the length of the refrigerant path downwards, increasing the refrigerant flow rate in areas with lower dryness and subcooled regions to maintain a higher heat exchange coefficient. Thus, the performance of the outdoor heat exchanger 100 is improved under different operating conditions, enhancing the overall efficiency of the outdoor heat exchanger 100.

[0060] Specifically, when the outdoor heat exchanger 100 acts as a condenser, the refrigerant enters the heat exchanger body 1 through the first main inlet / outlet 14 and flows to the first end 111 of multiple first heat exchange flow paths, where it exchanges heat with the multiple first heat exchange flow paths. Then, the refrigerant flows from the second end 112 of the multiple first heat exchange flow paths to the third end 121 of the second heat exchange flow path, where it exchanges heat with the second heat exchange flow path. Finally, the refrigerant flows from the fourth end 122 of the second heat exchange flow path through the gas outlet 221 and the second inlet / outlet 223 to the sixth end 132 of the third heat exchange flow path. At this time, the gas-liquid separator 2, acting as a straight pipe, does not perform gas-liquid separation. After exchanging heat in the third heat exchange flow path, the refrigerant flows from the fifth end 131 of the third heat exchange flow path to the second main inlet / outlet 15 and then out of the heat exchanger body 1.

[0061] When the outdoor heat exchanger 100 is used as an evaporator, the refrigerant enters the heat exchanger body 1 through the second main inlet / outlet 15 and flows into the third heat exchanger through the fifth end 131 for heat exchange. After heat exchange, the refrigerant flows into the gas-liquid separator 2 through the sixth end 132 and the second inlet / outlet 223 of the third heat exchanger. After separation by the gas-liquid separator 2, the gaseous refrigerant flows out from the gas outlet 221, and the liquid refrigerant flows from the first inlet / outlet 222 through the first control valve 3 to the second end 112 of the multiple first heat exchange flow paths and the third end 121 of the second heat exchange flow paths. The liquid refrigerant flows out from the first end 111 of the multiple first heat exchange flow paths, the fourth end 122 of the second heat exchange flow path, and the gaseous refrigerant flowing out from the gas outlet 221 after heat exchange with the refrigerant ...

[0062] In some embodiments of the present invention, as shown in Figures 1-3, there are two first flow paths 11. This arrangement improves the performance of the outdoor heat exchanger 100 in both cooling and heating modes, thereby increasing the overall efficiency of the outdoor heat exchanger 100. The following section specifically discusses, based on experimental evidence, how having two first flow paths 11 improves the performance of the outdoor heat exchanger 100 in both cooling and heating modes.

[0063] Because the heat exchange flow path of this application incorporates a gas-liquid separator 2, the heat exchange flow path is relatively complex. Furthermore, when the outdoor heat exchanger 100 acts as an evaporator, the gaseous refrigerant from the gas-liquid separator 2 flows out from the gas outlet 221, achieving a gas bypass position. The refrigerant mass flow rate within the heat exchange flow path will abruptly change at the gas bypass position, thus affecting the refrigerant-side heat transfer and pressure drop characteristics of the outdoor heat exchanger 100. Therefore, the gas bypass position and the number of branches after liquid refrigerant distribution will significantly impact the overall performance of the evaporator. For example, moving the gas bypass position further downstream will increase the dryness of the second inlet and outlet 223 of the gas-liquid separator 2, increasing the bypassed gaseous refrigerant mass flow rate. This leads to a change in the refrigerant mass flow rate distribution characteristics within the evaporator tubes, affecting the heat transfer and pressure drop characteristics within the tubes, and consequently, the overall performance of the evaporator. The number of branches after the liquid refrigerant will affect the refrigerant pressure drop characteristics during the latter part of the heat exchange, thus significantly impacting the evaporator performance.

[0064] It should be noted that the gas bypass location refers to the ratio of the number of heat exchange flow paths before gas bypass to the total number of heat exchange flow paths, denoted by β. Changes in β will affect the refrigerant mass flow distribution characteristics within the evaporator tubes, thus influencing the evaporator's heat transfer and pressure drop characteristics. For example, when there are two first flow paths 11, β can be expressed as the area proportion of the third heat exchange flow path in the entire outdoor heat exchanger, i.e., β = 0.25.

[0065] Meanwhile, since neither the heat transfer coefficient nor the pressure drop alone can accurately measure the overall performance of a heat exchanger, entropy production, based on the second law of thermodynamics, is used as an evaluation index for the overall performance of the evaporator to comprehensively consider the impact of these two factors. Under the condition of ensuring heat exchange, the smaller the entropy production of the evaporator, the smaller the irreversible losses caused by the evaporator's heat exchange temperature difference and fluid pressure drop, and the lower the compressor's power consumption, which is beneficial to improving system performance.

[0066] Entropy production characterizes irreversible losses in heat transfer and flow processes in heat exchangers and can be calculated using the following formula:

[0067]

[0068] S gen =∑(δS) gen,a +δS gen,r (3)

[0069] Where: δS gen.a and δS gen.r —Entropy production on the air and refrigerant sides of the micro-element control volume / W·K⁻¹;

[0070] S gen —Total entropy production of heat exchanger / W·K⁻¹;

[0071] T w T a and Tr —Pipe wall, air and refrigerant temperature / K;

[0072] V α and V r —Flow rates on the air and refrigerant sides of the micro-element control unit;

[0073] P α and P r —The pressure on the air side and the refrigerant side of the micro-element control body.

[0074] It should be noted that the air side of the micro-element control unit refers to the outer wall side of the heat exchange tube, while the refrigerant side refers to the inner wall side of the heat exchange tube.

[0075] For a single-row 1.5P air conditioner, the rated heating capacity is 5000W under the following conditions (outdoor 7℃ / 6℃, indoor 20℃ / 15℃). Under this rated heating condition, the entropy production of the evaporator is calculated by changing the gas bypass position β (i.e., the pipe area of ​​the heat exchange flow path before entering the gas-liquid separator) or the number of branches after the distributor. By analyzing the change of entropy production with the gas bypass position β, the arrangement position of the gas-liquid separator in the heat exchanger is determined. When β changes, it is assumed that the refrigerant after the distributor is still divided into 3 branches, and the length and flow rate of each branch are evenly distributed; when the number of branches after the distributor is changed, it is assumed that β is still 0.25.

[0076] The overall calculation process for entropy production of a gas bypass evaporator is shown in Figure 5, and is briefly described below:

[0077] (1) The input parameters for the calculation include: evaporator structural parameters, evaporator gas bypass position β, air inlet parameters, and evaporator inlet refrigerant enthalpy h. in Evaporator outlet superheat T sup.o And the required heat exchange capacity Q0. Without changing the indoor condenser parameters and its heat exchange conditions, the condenser outlet state does not change much. Therefore, the condenser outlet enthalpy can be approximated as a constant value. If the throttling element can achieve isoenthalpic throttling, then the evaporator inlet enthalpy can be considered unchanged, and the evaporator inlet enthalpy can be used as one of the inlet conditions.

[0078] (2) Divide the control volume into micro-element sections according to equal tube lengths, and obtain the heat exchange, pressure drop, and evaporator outlet parameters using the distributed parameter method. Adjust the evaporator inlet pressure p based on the evaporator outlet superheat as the criterion value. e.in This is because the inlet pressure of the evaporator differs depending on the flow path. The expansion valve typically adjusts its opening based on the evaporator outlet superheat, which in turn affects the evaporator inlet pressure. Therefore, the calculated evaporator outlet superheat T... sup With the set value T sup.o The difference is used to iteratively adjust the evaporator inlet pressure to simulate the adjustment process of the expansion valve.

[0079] (3) The calculation must ensure that the heat exchange of the evaporator is the same. The refrigerant flow rate m is iterated based on the difference between the calculated heat exchange rate Q and the required value Q0. r .

[0080] (4) The entropy production S of the evaporator was calculated. gen value.

[0081] Therefore, by changing the gas bypass position β (after distribution, the refrigerant is still divided into 3 paths, and the length and flow rate of each branch pipe are evenly distributed), the corresponding entropy production results are calculated as shown in Table 1. Evaporator entropy production S gen The value of β first decreases and then increases, reaching a minimum at β = 25%. There are two main reasons for this: First, as β increases, the proportion of the heat exchanger in the high-velocity zone (third flow path 121) increases, leading to an increase in the average flow velocity within the tubes. This increase in average velocity helps improve the average heat transfer coefficient within the tubes, but it also increases the pressure drop ΔP within the tubes. Under these two influences, there exists an optimal β that minimizes the evaporator entropy production. Second, the dryness of the refrigerant entering the gas-liquid separator increases with β, thus allowing for the bypass of more gaseous refrigerant. Insufficient gas bypass has little effect on evaporator performance, while excessive bypass leads to a significant decrease in the average heat transfer coefficient of the latter half of the heat exchanger. Therefore, there exists an optimal gas bypass quantity corresponding to the optimal β.

[0082] Table 1. Evaporator entropy production at different gas bypass locations.

[0083]

[0084]

[0085] Meanwhile, the entropy production results were calculated by changing the number of outlet branches (β remains at 0.25), as shown in Table 2. Under given heat exchange conditions, the evaporator entropy production S increases with the increase of the number of outlet branches. gen The number of circuits first decreases and then increases, reaching a minimum when the number of circuits is 3. The main reason is that as the number of circuits increases, the evaporator heat transfer coefficient and refrigerant pressure drop decrease. Reducing the refrigerant pressure drop can reduce evaporator entropy production, but reducing the evaporator heat transfer coefficient will lead to an increase in evaporator entropy production. Under the combined effect of these two factors, there exists an optimal number of circuits that minimizes evaporator entropy production.

[0086] Table 2 Evaporator entropy production corresponding to different distributor outlet branch numbers.

[0087] Distributor branch count: 12345S gen / W·K -1 1.577 1.537 1.528 1.549 1.583 surface

[0088] Since the location of the gas bypass and the number of branch paths after the liquid refrigerant enters the distributor have a significant impact on the overall performance of the evaporator, the location of the gas bypass and the number of branch paths after distribution were calculated and compared based on the entropy production minimization method. The results show that the entropy production of the system is minimized when the gas-liquid separator is arranged at 25% of the heat exchange area (i.e., the third heat exchange flow path connects to the second inlet and outlet of the gas-liquid separator via the 3U outlet) and the number of branch paths of the distributor is 3. Therefore, the flow path designed based on the above results can maximize the utilization of the bypass gas from the gas-liquid separator for secondary evaporation, thereby effectively improving the evaporator performance.

[0089] The above analysis shows that the gas bypass location β and the number of distributor branches both affect the overall performance of the evaporator, and they influence each other. The optimal β varies depending on the number of distributor branches, making it impossible to find the optimal flow path for the gas bypass evaporator by controlling variables. A global optimization algorithm is needed for its design optimization, and the genetic algorithm is a commonly used one. Therefore, using evaporator entropy production as the objective function, a genetic algorithm is used to construct a flow path optimization model for the gas bypass evaporator. The flow path information (gas bypass location, number of distributor branches), structural parameters (number of pipe rows, number of pipes per row, length of a single pipe, pipe outer diameter, fin spacing), and operating condition parameters (condensing temperature, condenser outlet subcooling, evaporator inlet air temperature, evaporator inlet air relative humidity, air volume, and required heat exchange) are used as input parameters for the algorithm.

[0090] Based on the above definition, as shown in Figure 6, the calculation process for determining the optimal flow path of the gas bypass evaporator using a genetic algorithm can be summarized as follows.

[0091] Initialize the population and encode it. Currently, the commonly used encoding methods are binary encoding and floating-point encoding. However, this paper quantizes the evaporator flow path information into integers and decimals, which is more suitable for floating-point encoding.

[0092] To assess the fitness of the population, since the genetic algorithm selects individuals with higher fitness, while this paper uses the evaporator to minimize entropy production as the optimization objective, a certain transformation is required to obtain the fitness F.

[0093] F = DS g (β, number of branches) (4)

[0094] In the formula, D is the estimated maximum entropy production value.

[0095] Selection: Based on the individual fitness, the roulette wheel selection algorithm is used to select individuals with smaller evaporator entropy output.

[0096] Crossover: Among the selected individuals, the paternal and maternal individuals are randomly selected, and single-point crossover inheritance is performed with a certain probability to produce new individuals.

[0097] Mutation: To ensure population diversity and avoid the algorithm from converging to a local optimum, it is necessary to perform gene mutation processing on individuals in the population using a uniform mutation algorithm with a certain probability.

[0098] Based on the newly obtained population, calculate the current value F of the fitness function and the average value F of the fitness function over the past 10 generations. 10,av

[0099] Termination Criterion: If F and F 10,av If the relative deviation is less than the set precision ε, the optimal point is considered to have been found and the algorithm terminates; otherwise, step 1 needs to be repeated until the algorithm converges.

[0100] Based on the above algorithm, calculations were performed on the gas bypass evaporator proposed in the invention's technical solution for a design heat exchange rate of 2kW to 8kW to find the optimal evaporator flow path under different heat exchange rates (while other input parameters remain unchanged). Different heat exchange rates correspond to different refrigerant mass flow rates within the evaporator tubes, resulting in different heat transfer and pressure drop characteristics within the tubes. Therefore, the optimal refrigerant flow path differs for different heat exchange rates.

[0101] As shown in Table 3, when the designed heat exchange capacity increases, the gas bypass position corresponding to the optimal evaporator flow path also increases (i.e., the area of ​​the third flow path 12 continuously increases). As the evaporation process proceeds, the refrigerant velocity inside the tubes increases, meaning that in the latter half of the heat exchanger, the pressure drop gradient on the refrigerant side is larger. Improving the gas bypass technology can effectively reduce the pressure drop on the refrigerant side of the latter half of the evaporator. Therefore, as the heat exchange capacity increases, the pressure drop gradually becomes the main factor limiting the overall performance of the evaporator. Moving the gas bypass point further back can increase the mass flow rate of the bypassed gaseous refrigerant, reducing the refrigerant velocity and pressure drop in the latter half of the tubes. Furthermore, as the refrigerant velocity inside the tubes increases, the increased turbulence makes it easier for mist to form inside the evaporator tubes. To reduce the area of ​​the mist heat transfer region in the latter half of the heat exchanger, the gas bypass point can be moved further back to reduce the velocity inside the tubes. Due to these two points, the gas bypass point corresponding to the optimal refrigerant flow path moves further back as the heat exchange capacity increases. When the heat exchange rate increases from 2kW to 8kW, the optimal number of circuits for the evaporator will be greater for higher load conditions. This is because a higher load results in a greater pressure drop within the evaporator, and this pressure drop has a more significant impact on evaporator performance, requiring more circuits to reduce the pressure drop. In summary, for high heat exchange conditions, gas bypass evaporators should appropriately increase the number of circuits and move the gas bypass point further back to achieve optimal overall evaporator performance.

[0102] Table 3 Optimal Evaporator Flow Paths for Designed Heat Exchange Capacities of 2kW to 8kW

[0103]

[0104]

[0105] In some embodiments of the present invention, as shown in Figures 1-3, multiple heat exchange tubes 16 of the first flow paths 11 are arranged in the height direction of the outdoor heat exchanger 100 (the first direction shown in Figure 1). This arrangement allows the refrigerant within each heat exchange tube 16 of the first flow path 11 to better exchange heat with the surrounding environment during its flow, thereby improving heat exchange efficiency. Simultaneously, the arrangement of multiple heat exchange tubes 16 of the first flow paths 11 in the height direction of the outdoor heat exchanger 100 allows for more efficient use of the space in the height direction of the outdoor heat exchanger 100, resulting in a more compact structure for the outdoor heat exchanger 100.

[0106] In some embodiments of the present invention, as shown in Figures 1-3, the outdoor heat exchanger 100 further includes a first manifold 6 and a second manifold 7. The first manifold 6 is connected to the gas outlet 221, the fourth end 122, and the first main inlet / outlet 14, respectively. The second manifold 7 is connected to the first manifold 6 and the first end 111, respectively. A second control valve 4 is connected in series between the first manifold 6 and the second manifold 7.

[0107] Understandably, when the outdoor heat exchanger 100 acts as an evaporator, the refrigerant enters the heat exchanger body 1 through the second main inlet / outlet 15 and flows into the third heat exchanger through the fifth end 131 for heat exchange. After heat exchange, the refrigerant flows into the gas-liquid separator 2 through the sixth end 132 and the second inlet / outlet 223 of the third heat exchanger. After separation by the gas-liquid separator 2, the gaseous refrigerant flows from the gas outlet 221 into the first manifold 6 and then into the second manifold 7. The liquid refrigerant flows from the first inlet / outlet 222 through the first control valve 3 to the second end 112 of the first heat exchange flow path and the third end 121 of the second heat exchange flow path. The refrigerant that has exchanged heat with the first heat exchange flow path flows from the first end 111 of the first heat exchange flow path and the refrigerant that has exchanged heat with the second heat exchange flow path flows from the fourth end 122 of the second heat exchange flow path into the second manifold 7. Finally, the refrigerant flows from the second manifold 7 to the first main inlet / outlet 14 and then out of the heat exchanger body 1.

[0108] When the outdoor heat exchanger 100 is used as a condenser, the refrigerant enters the heat exchanger body 1 through the first main inlet / outlet 14 and flows to the second manifold 7. After exchanging heat with the first heat exchange path, the refrigerant flows from the second end 112 of the first heat exchange path to the third end 121 of the second heat exchange path and exchanges heat with the second heat exchange path. After exchanging heat with the second heat exchange path, the refrigerant flows from the fourth end 122 of the second heat exchange path to the first manifold 6. After exchanging heat with the first manifold 6, the refrigerant flows to the gas outlet 221 and then through the second inlet / outlet 223 to the sixth end 132 of the third heat exchange path. After exchanging heat with the third heat exchange path, the refrigerant flows from the fifth end 131 of the third heat exchange path to the second main inlet / outlet 15 and then flows out of the heat exchanger body 1.

[0109] In some embodiments of the present invention, as shown in Figures 1-3, the heat exchange tubes 16 of the first flow path 11, the second flow path 12, and the third flow path 13 are arranged sequentially along the height direction of the outdoor heat exchanger 100. This arrangement allows the refrigerant in each of the heat exchange tubes 16 of the first flow path 11, the second flow path 12, and the third flow path 13 to better exchange heat with the surrounding environment during flow, thereby improving heat exchange efficiency. Simultaneously, the sequential arrangement of the heat exchange tubes 16 of the first flow path 11, the second flow path 12, and the third flow path 13 along the height direction of the outdoor heat exchanger 100 more effectively utilizes the space in the height direction of the outdoor heat exchanger 100, making the structure of the outdoor heat exchanger 100 more compact.

[0110] In some embodiments of the present invention, as shown in Figures 1-4, the gas-liquid separator 2 includes a housing 21 and a first pipeline 22. A gas outlet 221, a first inlet / outlet 222, and a second inlet / outlet 223 are disposed on the housing 21. One end of the first pipeline 22 is connected to the gas outlet 221, and the other end of the first pipeline 22 connected to the gas outlet 221 extends into the gas-liquid separator 2 or is flush with the outer end face of the gas-liquid separator 2.

[0111] Understandably, after the gas-liquid two-phase refrigerant enters the housing 21 through the second inlet / outlet 223 for gas-liquid separation, the gaseous refrigerant flows from the gas outlet 221 to the first pipe 22, and the liquid refrigerant flows to the liquid outlet. Simultaneously, the end of the first pipe 22 connected to the gas outlet 221 extends into the gas-liquid separator 2, increasing the time the gas spends in the housing 21 before being discharged. This increases the contact area and time between the gas and liquid, helping to more thoroughly separate the gas from the liquid, reducing the amount of liquid carried by the gas during discharge, and improving gas-liquid separation efficiency. Alternatively, the end of the first pipe 22 connected to the gas outlet 221 can extend flush with the outer end face of the gas-liquid separator 2, simplifying the structure of the gas-liquid separator 2, reducing complexity, facilitating the assembly and disassembly of the first pipe 22, and improving efficiency.

[0112] Furthermore, the gas-liquid separator 2 also includes a second pipe 23 and a third pipe 24. One end of the second pipe 23 is connected to the second inlet / outlet 223, and one end of the third pipe 24 is connected to the first inlet / outlet 222. Thus, the gas-liquid two-phase refrigerant enters the second pipe 23 through the end away from the second inlet / outlet 223 and enters the housing 21 through the second inlet / outlet 223, while the liquid phase refrigerant flows from the first inlet / outlet 222 to the third pipe 24.

[0113] Since the gas-liquid separator 2 is the core component for gas bypass when the outdoor heat exchanger 100 acts as an evaporator, its separation performance has a significant impact on system operation. Poor gas-liquid separation performance will lead to severe liquid carryover at the gas outlet 221, thereby affecting the reliability of the compressor and causing the loss of some of the latent heat of vaporization carried by the liquid refrigerant, resulting in a decline in the performance of the heat exchange system. Therefore, the specific dimensions of the gas-liquid separator 2 are demonstrated below based on the inventor's experiments.

[0114] For a single-row 1.5P air conditioner with a rated heating capacity of 5000W under heating conditions (outdoor 7℃ / 6℃, indoor 20℃ / 15℃), the flow rate range of the gas bypass evaporator under different operating conditions was calculated to be 6~20g·s based on the prototype experimental data of the air conditioner. -1 (R290 refrigerant). A gas-liquid separator 2 was used in a gas bypass evaporator. A CFD simulation model of the gas-liquid separator 2 was established. Based on this, the influence of structural parameters on the performance of the gas-liquid separator 2 was investigated, and a gas-liquid separator 2 suitable for the applied operating conditions was obtained. Generally, the higher the flow rate of the second inlet and outlet 223 of the gas-liquid separator 2, the worse the separation performance. Therefore, during the structural optimization process, a maximum flow rate of 15 g·s was used. -1 As design conditions, the performance of the gas-liquid separator 2 is guaranteed under the maximum flow rate condition of the system. Furthermore, in gas bypass evaporators, the dryness of the second inlet and outlet 223 of the gas-liquid separator 2 is typically between 0.15 and 0.45; therefore, a dryness of 0.3 is used as the design condition. The structural parameters and boundary conditions during the simulation process are shown in Table 4.

[0115] Table 4 Simulation structural parameters and boundary conditions

[0116]

[0117] Before optimizing the structure of gas-liquid separator 2, the criteria for evaluating separation efficiency should first be determined to describe the performance of gas-liquid separation. In gas-liquid separator 2, F is commonly used. v To characterize the proportion of gaseous refrigerant flowing out of gas outlet 221, F lThe proportion of liquid refrigerant flowing out of gas outlet 221 is characterized by equations (5) and (6). For a high-performance gas-liquid separator 2, it is generally desirable to have as much gaseous refrigerant flowing out of gas outlet 221 as possible, while minimizing the amount of liquid refrigerant flowing out of gas outlet 221. Therefore, F is often used. v With F l The difference is used as the formula for calculating the gas-liquid separation efficiency η, as shown in equation (7):

[0118]

[0119] η = F v -F l (7)

[0120] Where: m2 and m1 are the refrigerant flow rates at the gas outlet and inlet, respectively, in kg·s. -1 x2 and x1 — refrigerant dryness at gas outlet 221 and inlet.

[0121] Furthermore, the dryness of the gas outlet 221 in the gas-liquid separator 2 should also be considered. Typically, the dryness of the gas outlet needs to be close to 1; otherwise, it will affect the performance of the gas bypass evaporator and the operational stability of the compressor. Therefore, this paper uses the gas-liquid separation efficiency η and the dryness of the gas outlet 221 x2 as the main evaluation indicators for the performance of the gas-liquid separator 2.

[0122] First, the internal flow field of gas-liquid separator 2 is described to better understand the mechanism of the cyclone gas-liquid separation device, facilitating subsequent structural design. The boundary conditions shown in Table 4 are used to simulate the internal flow process of the gas-liquid separation device, and the specific structural parameters are shown in Table 5.

[0123] Table 5 Structural parameters for flow property study

[0124]

[0125] According to the internal streamline diagram and the gas phase volume fraction distribution cloud diagram of the central section of the gas-liquid separator 2, it can be seen that the flow of the gas-liquid mixture in the gas-liquid separator 2 is divided into the following parts: (1) After the gas-liquid two-phase flow enters the main tube tangentially from the second inlet and outlet 223, under the action of gravity and centrifugal force, they will roll and flow downward along the wall. During this process, the liquid is thrown to the wall and flows along the wall due to its high density, while some gas is separated due to its low density, gathers in the middle and rolls upward under the action of buoyancy; (2) The liquid at the bottom of the gas-liquid separator 2 The gas flows downward from the first inlet and outlet 222. As can be seen from the gas phase volume fraction cloud diagram, due to the excessive flow rate, the bottom liquid surface cannot be well sealed, and vortices will appear. (3) When the gas moving with the liquid rotates and hits the bottom liquid surface, part of it will flow upward. Since the liquid surface is not sealed, the other part of the gas will flow directly from the middle vortex to the first inlet and outlet 222. (4) The upward flowing gas has two destinations. Part of it gathers at the top of the separator and forms a vortex, while the other part flows out from the gas outlet 221.

[0126] When first studying the effect of the inner diameter of the shell 21 on the performance of the gas-liquid separator 2, the axial dimension of the inner cavity of the shell 21 was 120 mm and the dimension of the first pipe 22 extending into the gas-liquid separator 2 was 30 mm. Only the inner diameter of the shell 21 of the gas-liquid separator 2 was changed. Table 6 shows the mass flow rate of 20 g·s. -1 At that time, the gas-liquid separation efficiency η and the dryness of the gas outlet 221 x2 increase with the inner diameter d of the shell 21. sep The change is evident. It can be seen that as the inner diameter of the shell 21 increases from 30 mm to 80 mm, at a flow rate of 20 g·s⁻¹... -1 At this time, η and x2 first increase and then decrease with increasing separation diameter. When the flow rate is 20 g·s -1 When the inner diameter of the shell 21 increases to 40 mm, its separation performance is relatively high, with the dryness of the gas outlet 221 and the separation performance being 0.953 and 0.856, respectively. After that, the change range with the continued increase of the inner diameter of the shell 21 is relatively small, and the separation performance is the highest when the inner diameter of the shell 21 is 60 mm.

[0127] The gas-liquid separation performance η and the gas outlet dryness x2 initially increase with the increase of the inner diameter of the shell 21, but the rate of increase slows down. When the diameter exceeds a certain value, the separation performance actually decreases. The reasons are as follows: When the diameter is small, as the inner diameter of the shell 21 increases, the distance between the liquid on the wall and the gas outlet 221 increases, and the gas-liquid carryover phenomenon is improved. However, when the inner diameter of the shell 21 is large, as the inner diameter of the shell 21 increases further, the residence time of the gas and liquid phases in the shell 21 is too long, the rotational flow energy in the shell 21 is severely lost, the upper fluid cannot effectively drive the bottom fluid to rotate, resulting in a weakening of the centrifugal force for the separation of the two phases at the bottom, the gas and liquid phases at the bottom cannot be effectively separated, and the gas content of the bottom liquid increases. Therefore, further increasing the diameter cannot improve the gas-liquid separation performance.

[0128] In summary, when the flow rate is 20 g·s⁻¹, the separation efficiency is relatively high when the inner diameter of the housing 21 of the gas-liquid separator 2 is 40 mm. Increasing it further to 70 mm will slightly improve the separation performance. Therefore, the minimum inner diameter of the housing 21 is 40 mm.

[0129] Table 6. Influence of the inner diameter of shell 21 on the performance of gas-liquid separator 2

[0130]

[0131]

[0132] When studying the influence of the axial dimension of the inner cavity of the housing 21 on the performance of the gas-liquid separator 2, the inner diameter of the housing 21 is 50 mm and the dimension of the first pipe 22 extending into the gas-liquid separator 2 is 40 mm. Only the axial dimension of the inner cavity of the housing 21 is changed.

[0133] Table 7 shows the mass flow rate of 20 g·s⁻¹. -1 The table shows the trends of gas-liquid separation efficiency η and gas outlet dryness x2 with the axial dimension of the inner cavity of the shell 21. As the axial dimension of the inner cavity of the shell 21 increases from 60 mm to 160 mm, both the gas-liquid separation efficiency η and the gas outlet dryness x2 increase with the increase of the axial dimension of the inner cavity of the shell 21, but the rate of increase slows down. When the axial dimension of the inner cavity of the shell 21 is 60 mm, the separation performance is very poor, with gas outlet dryness x2 and separation performance η being 0.663 and 0.628, respectively. When the axial dimension of the inner cavity of the shell 21 increases to 120 mm, the separation performance is relatively high, and the rate of change with further increases in the axial dimension of the inner cavity of the shell 21 becomes relatively small. As the axial dimension of the inner cavity of the shell 21 increases, the gas outlet 221 is farther from the bottom liquid surface, reducing the possibility of droplets splashing into the gas outlet. Simultaneously, the increased axial dimension of the inner cavity of the shell 21 prolongs the residence time of the gas and liquid phases within the shell 21, which helps to achieve sufficient separation. Therefore, the liquid carryover phenomenon at the gas outlet 221 is mitigated, and the gas-liquid separation performance and the dryness of the gas outlet 221 are improved. However, as the axial dimension of the inner cavity of the shell 21 further increases, the rotational flow energy within the shell 21 is severely lost. The upper fluid cannot effectively drive the bottom flow fluid to rotate, resulting in a weakening of the centrifugal force for the separation of the two phases at the bottom. The bottom gas and liquid phases cannot be effectively separated, and the gas content in the bottom liquid increases. Therefore, further increasing the length cannot effectively improve the gas-liquid separation performance.

[0134] In summary, when the flow rate is 20 g / s -1When the axial dimension of the inner cavity of the housing 21 is 100mm, the separation efficiency is already relatively high. Therefore, the minimum axial dimension of the inner cavity of the housing 21 is 100mm.

[0135] Table 7. Influence of the axial dimension of the inner cavity of the shell 21 on the performance of the gas-liquid separator 2

[0136]

[0137] When studying the influence of the size of the first pipe 22 extending into the gas-liquid separator 2 on the performance of the gas-liquid separator 2, the inner diameter of the shell 21 is 40mm and the axial dimension of the inner cavity of the shell 21 is 120mm. Only the size of the first pipe 22 extending into the gas-liquid separator 2 is changed.

[0138] Table 8 shows the mass flow rate of 20 g·s⁻¹. -1 The trends of gas-liquid separation efficiency η and gas outlet dryness x2 with interpolation depth are shown. It can be seen that as the length of the first pipe 22 extending into the gas-liquid separator 2 increases from 0 mm to 60 mm, both the gas-liquid separation performance η and the gas outlet dryness x2 initially increase and then decrease with the increase in the length of the first pipe 22 extending into the gas-liquid separator 2. This is because as the length of the first pipe 22 extending into the gas-liquid separator 2 increases, the fluid travels through the first pipe 22, resulting in more efficient gas-liquid separation. However, when the length of the first pipe 22 extending into the gas-liquid separator 2 becomes too large, the distance between the bottom of the first pipe 22 and the bottom liquid surface becomes shorter, exacerbating the gas-liquid carryover phenomenon caused by droplet splashing, etc., and worsening the gas-liquid separation performance. When the length of the first pipe 22 extending into the gas-liquid separator 2 increases to 30 mm, the separation performance is relatively high; further increases in the length of the pipe extending into the gas-liquid separator 2 result in a further decrease in separation performance. Therefore, the maximum length of the first pipe 22 extending into the gas-liquid separator 2 is 30 mm.

[0139] Table 8. Influence of the dimensions of the first pipe 22 extending into the gas-liquid separator 2 on the performance of the gas-liquid separator 2

[0140]

[0141] In some embodiments of the present invention, the gas outlet 221 and the first inlet / outlet 222 are located at the two end faces of the gas-liquid separator 2 in the axial direction, respectively, and the second inlet / outlet 223 is located on the side wall of the gas-liquid separator 2. It is understood that by setting the gas outlet 221 and the first inlet / outlet 222 at the two end faces of the gas-liquid separator 2 in the axial direction, the residence time of the gas-liquid mixture in the gas-liquid separator 2 can be extended, which is beneficial for more complete gas-liquid separation and improves the gas-liquid separation effect.

[0142] Specifically, in practical applications, the gas outlet 51 of the gas separator 2 is located below the first inlet and outlet 222, so that the liquid will naturally flow downward due to gravity, while the gas tends to move upward, thereby making full use of the effect of gravity to accelerate the gas-liquid separation process.

[0143] In some embodiments of the present invention, there are two second inlets / outlets 223, which are symmetrically arranged along the central axis of the gas-liquid separator 2. It is understood that, as shown in Figure 7, the internal streamline diagram of the gas-liquid separator 2 with one second inlet / outlet 223 shows a significant eccentricity in the internal streamlines and liquid surface, and the central gas column streamline fluctuates considerably, easily leading to gas-liquid entrainment. As shown in Figure 8, the internal streamline diagram of the gas-liquid separator 2 with two second inlets / outlets 223 shows a more regular internal streamline, with both the streamlines and the bottom liquid surface exhibiting axial symmetry, and the central gas column is more stable, thus improving the gas-liquid entrainment phenomenon. Therefore, by symmetrically arranging the two second inlets / outlets 223 along the central axis of the gas-liquid separator 2, it is beneficial to stably and efficiently separate the gas and liquid refrigerant, improving the heat exchange efficiency of the outdoor heat exchanger 100 as an evaporator.

[0144] Furthermore, there are two second pipes 23 corresponding to the second inlet and outlet 223, with one end of each second pipe 23 connected to the corresponding second inlet and outlet 223. Thus, the gas-liquid two-phase refrigerant enters the second pipe 23 through the end of each second pipe 23 away from the second inlet and outlet 223 and enters the housing 21 through the corresponding second inlet and outlet 223.

[0145] The outdoor heat exchanger 100 of a specific embodiment of the present invention will be described in detail below with reference to Figures 1-4. It should be understood that the following description is merely illustrative and should not be construed as limiting the invention.

[0146] The outdoor heat exchanger 100 includes a heat exchanger body 1, a gas-liquid separator 2, a first control valve 3, a second control valve 4, a distributor 5, a first manifold 6, and a second manifold 7. The heat exchanger body 1 has multiple heat exchange tubes 16 and a heat exchange flow path. This flow path has a first total inlet / outlet 14 and a second total inlet / outlet 15, and includes a first flow path 11, a second flow path 12, and a third flow path 13. There are two first flow paths 11, with the first end 111 and the second end 112 along their length. The second flow path 12 has the third end 121 and the fourth end 122 along its length. The third flow path 13 has the fifth end 131 and the sixth end 132 along its length. The first end 111 is connected to the first total inlet / outlet 14, and the fifth end 131 is connected to the second total inlet / outlet 15. The gas-liquid separator 2 has a gas outlet 221, a first inlet / outlet 222, and a second inlet / outlet 222. 3. The second end 112, the third end 121 and the first inlet / outlet 222 are connected, the second inlet / outlet 223 is connected to the sixth end 132, the gas outlet 221 is connected to the fourth end 122 and the first end 111, the first control valve 3 is connected in series between the second end 112, the third end 121 and the first inlet / outlet 222, the second control valve 4 is connected in series between the first end 111 and the fourth end 122, one end of the first flow path 11, one end of the second flow path 12 and the first inlet / outlet 222 are connected through the distributor 5, the first manifold 6 is connected to the gas outlet 221, the fourth end 122 and the first main inlet / outlet 14 respectively, the second manifold 7 is connected to the first manifold 6 and the first end 111 respectively, and the second control valve 4 is connected in series between the first manifold 6 and the second manifold 7.

[0147] When the outdoor heat exchanger 100 is used as a condenser, the first control valve 3 is controlled to disconnect the connection between the second end 112 and the third end 121 and the first inlet and outlet 222, and the second control valve 4 is controlled to connect the first flow path 11 and the second flow path 12 and only allow the flowing medium to flow from the other end of the second flow path 12 to the other end of the first flow path 11.

[0148] Thus, the refrigerant enters the heat exchanger body 1 through the first main inlet / outlet 14 and flows into the second manifold 7. From the second manifold 7, it flows to the first end 111 of multiple first heat exchange paths and exchanges heat with them. Then, the refrigerant flows from the second end 112 of the multiple first heat exchange paths to the distributor 5, and from the distributor 5 to the third end 121 of the second heat exchange path and exchanges heat with it. From the fourth end 122 of the second heat exchange path, the refrigerant flows to the first manifold 6, and from the first manifold 6 to the gas outlet 221, then through the second inlet / outlet 223 to the sixth end 132 of the third heat exchange path. After exchanging heat in the third heat exchange path, the refrigerant flows from the fifth end 131 of the third heat exchange path to the second main inlet / outlet 15 and then out of the heat exchanger body 1.

[0149] When the outdoor heat exchanger 100 is used as an evaporator, the first control valve 3 is controlled to connect the second end 112 and the third end 121 with the first inlet and outlet 222, and the second control valve 4 is controlled to disconnect the connection between the first flow path 11 and the second flow path 12.

[0150] Thus, the refrigerant enters the heat exchanger body 1 through the second main inlet / outlet 15 and flows into the third heat exchanger through the fifth end 131 for heat exchange. After heat exchange, the refrigerant flows into the gas-liquid separator 2 through the sixth end 132 and the second inlet / outlet 223 of the third heat exchanger. After separation by the gas-liquid separator 2, the gaseous refrigerant flows from the gas outlet 221 into the first manifold 6 and then into the second manifold 7. The liquid refrigerant flows from the first inlet / outlet 222 through the first control valve 3 to the distributor 5, and then flows through the distributor 5 to the second end 112 of the multiple first heat exchange flow paths and the third end 121 of the second heat exchange flow paths. The refrigerant after heat exchange with the multiple first heat exchange flow paths flows from the first end 111 of the multiple first heat exchange flow paths and from the fourth end 122 of the second heat exchange flow path into the second manifold 7. Finally, the refrigerant flows from the second manifold 7 to the first main inlet / outlet 14 and out of the heat exchanger body 1.

[0151] In summary, this configuration improves the performance of the outdoor heat exchanger 100 in both cooling and heating modes, thereby enhancing the overall efficiency of the outdoor heat exchanger 100.

[0152] Other components of the outdoor heat exchanger 100 according to embodiments of the present invention, such as the distributor 5, the first manifold 6, and the second manifold 7, as well as their operation, are known to those skilled in the art and will not be described in detail here.

[0153] The air conditioner according to an embodiment of the present invention is described below.

[0154] An air conditioner according to an embodiment of the present invention includes an outdoor heat exchanger 100.

[0155] In the air conditioner's cooling mode, the outdoor heat exchanger 100 acts as an evaporator. The refrigerant enters the separation space of the gas-liquid separator 2 through the second inlet and outlet 223. Utilizing centrifugal force, the liquid refrigerant, due to its higher density, is thrown towards the wall of the shell 21 of the gas-liquid separator 2 and flows down the wall, exiting from the first inlet and outlet 222. The gaseous refrigerant, due to its lower density, accumulates in the central area and rises, exiting from the gas outlet 221. This effectively separates the gas-liquid mixture, allowing the refrigerant exiting from the first inlet and outlet 222 to exchange heat in the subsequent heat exchange tube 16. This reduces the inlet dryness of the refrigerant in the subsequent heat exchange tube 16, reduces the deterioration of evaporative heat transfer caused by excessive gaseous refrigerant, and reduces the flow resistance of the subsequent heat exchange tube 16. Consequently, it effectively improves the phenomenon of decreased heat exchange performance of the outdoor heat exchanger 100 when it acts as an evaporator due to excessive gaseous refrigerant, thereby improving heat exchange efficiency.

[0156] When the air conditioner is in heating mode, the outdoor heat exchanger 100 acts as a condenser. The first control valve 3 is controlled to disconnect the connection between the second end 112 and the third end 121 and the first inlet and outlet 222. The second control valve 4 is controlled to connect the first flow path 11 and the second flow path 12 and only allow the flowing medium to flow from the other end of the second flow path 12 to the other end of the first flow path 11. Thus, after the refrigerant enters the heat exchanger body 1 through the first main inlet / outlet 14, it flows to the first end 111 of the first heat exchange flow path and exchanges heat with the first heat exchange flow path. Then, the refrigerant flows from the second end 112 of the first heat exchange flow path to the third end 121 of the second heat exchange flow path and exchanges heat with the second heat exchange flow path. Finally, the refrigerant flows from the fourth end 122 of the second heat exchange flow path through the gas outlet 221 and the second inlet / outlet 223 to the sixth end 132 of the third heat exchange flow path. At this time, the gas-liquid separator 2, as a straight pipe, does not perform gas-liquid separation. After exchanging heat in the third heat exchange flow path, the refrigerant flows from the fifth end 131 of the third heat exchange flow path to the second main inlet / outlet 15 and then flows out of the heat exchanger body 1.

[0157] According to an embodiment of the present invention, an outdoor heat exchanger 100 is provided. A first control valve 3 is connected in series between the second end 112, the third end 121 and the first inlet / outlet 222. A second control valve 4 is connected in series between the first end 111 and the fourth end 122. This allows for diverse and flexible flow paths of the refrigerant in the heat exchange flow path, thereby enabling the outdoor heat exchanger 100 to switch between different numbers of flow paths in cooling and heating modes. This improves the performance of the outdoor heat exchanger 100 under different operating conditions and enhances the overall efficiency of the air conditioner. Meanwhile, the gas-liquid separator 2 has a gas outlet 221, a first inlet / outlet 222, and a second inlet / outlet 223. The second end 112, the third end 121, and the first inlet / outlet 222 are connected. The second inlet / outlet 223 is connected to the sixth end 132. The gas outlet 221 is connected to the fourth end 122 and the first end 111. This allows the refrigerant flowing out of the first inlet / outlet 222 to exchange heat in the subsequent heat exchange tube 16, thereby reducing the inlet dryness of the refrigerant in the subsequent heat exchange tube 16. This reduces the deterioration of evaporative heat transfer caused by excessive gaseous refrigerant and reduces the flow resistance of the subsequent heat exchange tube 16. In this way, it effectively improves the phenomenon that the outdoor heat exchanger 100 has a reduced heat exchange performance due to excessive gaseous refrigerant when it is used as an evaporator, and improves the heat exchange efficiency of the air conditioner.

[0158] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0159] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. An outdoor heat exchanger for use in an air conditioner, characterized in that, include: A heat exchanger body has multiple heat exchange tubes and a heat exchange flow path. The heat exchange flow path has a first main inlet and a second main inlet and includes a first flow path, a second flow path, and a third flow path. The two ends of the first flow path along its length are a first end and a second end, the two ends of the second flow path along its length are a third end and a fourth end, and the two ends of the third flow path along its length are a fifth end and a sixth end. The first end is connected to the first main inlet and the fifth end is connected to the second main inlet and the second main inlet and the second flow path. A gas-liquid separator has a gas outlet, a first inlet and a second inlet and a second inlet and a third end. The second end, the third end, and the first inlet and the second flow path are connected to the first inlet and the second flow path. The second inlet and the sixth flow path are connected to the fourth end and the first end. A first control valve and a second control valve are connected in series between the second end, the third end, and the first inlet and the second flow path. The second control valve is connected in series between the first end and the fourth end.

2. The outdoor heat exchanger according to claim 1, characterized in that, The first control valve is a solenoid valve; and / or, the second control valve is a check valve, which only allows the flowing medium to flow from the other end of the second flow path to the other end of the first flow path.

3. The outdoor heat exchanger according to claim 1, characterized in that, Also includes: A distributor, wherein one end of the first flow path, one end of the second flow path, and the first inlet / outlet are connected via the distributor.

4. The outdoor heat exchanger according to claim 1, characterized in that, The first flow path consists of multiple paths connected in parallel.

5. The outdoor heat exchanger according to claim 4, characterized in that, Multiple heat exchange tubes of the first flow path are arranged in the height direction of the outdoor heat exchanger.

6. The outdoor heat exchanger according to claim 4, characterized in that, The first flow path consists of two paths.

7. The outdoor heat exchanger according to claim 1, characterized in that, Also includes: A first manifold is connected to the gas outlet and the fourth end respectively; a second manifold is connected to the first manifold, the first end and the first main inlet and outlet respectively; and a second control valve is connected in series between the first manifold and the second manifold.

8. The outdoor heat exchanger according to claim 1, characterized in that, The gas-liquid separator includes: a housing, the gas outlet, the first inlet and outlet and the second inlet and outlet are disposed on the housing, the inner diameter of the housing is at least 40 mm; and / or, the axial dimension of the inner cavity of the housing is at least 100 mm.

9. The outdoor heat exchanger according to claim 1, characterized in that, The gas-liquid separator further includes: a first pipeline, one end of which is connected to the gas outlet, and the end of the first pipeline connected to the gas outlet extends into the gas-liquid separator or is flush with the outer end face of the gas-liquid separator.

10. The outdoor heat exchanger according to claim 9, characterized in that, One end of the first pipe connected to the gas outlet extends into the gas-liquid separator, and the maximum length of the first pipe extending into the gas-liquid separator is 30 mm.

11. The outdoor heat exchanger according to claim 1, characterized in that, The gas outlet and the first inlet / outlet are located at the two end faces of the gas-liquid separator in the axial direction, respectively, and the second inlet / outlet is located on the side wall of the gas-liquid separator.

12. The outdoor heat exchanger according to claim 1, characterized in that, The heat exchange tubes of the first flow path, the second flow path, and the third flow path are arranged sequentially along the height direction of the outdoor heat exchanger.

13. An air conditioner, characterized in that, Includes an outdoor heat exchanger according to any one of claims 1-12.

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