Design method for outdoor unit and heat exchanger of top air-out type air conditioner

Abstract

The invention discloses a top air outlet type air conditioner outdoor unit, and relates to the technical field of air conditioners. The top air outlet type air conditioner outdoor unit comprises a machine shell, a draught fan, a compressor and a heat exchanger. An air outlet is formed in the top of the shell; an air inlet is formed in the side surface of the shell; the draught fan, the compressor and the heat exchanger are arranged in the machine shell, the draught fan is close to the air outlet, the compressor is located below the draught fan, the windward side of the heat exchanger faces the air inlet, and the leeward side of the heat exchanger faces the compressor. The heat exchanger comprises a plurality of fins, and a fin gap allowing airflow to penetrate through is formed between every two adjacent fins. The fin gaps are arranged in the height direction of the heat exchanger. The heat exchanger comprises a plurality of heat exchange sections which are arranged in the height direction of the heat exchanger. The fin gaps of the heat exchange sections close to the lower end of the heat exchanger are larger than those of the heat exchange sections close to the upper end of the heat exchanger, so that resistance of the lower end of the heat exchanger is reduced, heat exchange efficiency of the lower end of the heat exchanger is improved, and material cost of the heat exchanger is reduced under the condition that overall heat exchange efficiency of the heat exchanger is not reduced.

Description

Technical Field

[0001] This application relates to the technical field of air conditioning, and more particularly to a design method for a top-discharge air conditioning outdoor unit and heat exchanger. Background Technology

[0002] In top-discharge outdoor units, because the fan is located near the top of the casing, the airflow is unevenly distributed along the height of the casing. The upper part of the heat exchanger is closer to the fan, resulting in higher air velocity and better heat exchange. However, the bottom of the heat exchanger is farther from the fan, resulting in relatively poor airflow and significantly reduced heat exchange efficiency. The uneven air velocity distribution along the casing height, with lower air velocity at the bottom, reduces the heat exchange efficiency at the bottom of the heat exchanger, preventing it from performing its intended heat exchange performance and resulting in wasted material costs.

[0003] Finned heat exchangers are a commonly used type of heat exchanger, and the fin gap is a crucial parameter affecting heat exchange efficiency. Reducing the fin gap increases the fin density, thereby expanding the contact area between the air and refrigerant, theoretically improving heat exchange efficiency. However, a smaller gap narrows the airflow channel, significantly increasing airflow resistance and reducing airflow, which may actually inhibit heat exchange. Increasing the fin gap reduces air resistance and increases airflow, but it reduces the effective heat exchange area, similarly hindering heat exchange efficiency optimization. The heat exchange area and air resistance form a contradictory constraint on the heat exchange efficiency of finned heat exchangers. Given the lower airflow velocity at the bottom of the heat exchanger, this contradiction further exacerbates the uneven heat exchange between the upper and lower ends of the heat exchanger in top-discharge outdoor units. Summary of the Invention

[0004] To address the shortcomings of related technologies, this application provides a design method for a top-discharge air conditioner outdoor unit and a heat exchanger. The heat exchanger is designed with multiple heat exchange sections in the height direction, with the lower heat exchange section having a larger fin gap and the upper heat exchange section having a smaller fin gap. This effectively solves the problem of uneven airflow distribution caused by the fan position in the top-discharge outdoor unit, making the heat exchange performance of the heat exchanger more uniform in the height direction. This reduces material costs without reducing the overall heat exchange efficiency of the heat exchanger or the overall performance of the unit.

[0005] In a first aspect, this application provides a top-discharge air conditioning outdoor unit, comprising: The housing includes an air outlet and an air inlet, with the air outlet located at the top of the housing and the air inlet located on the side of the housing. The fan is located inside the casing, near the air outlet; The compressor is located inside the casing, below the fan; The heat exchanger is located inside the casing, with its windward side facing the air inlet and its leeward side facing the compressor. The heat exchanger includes several fins, with fin gaps between adjacent fins for airflow to pass through; the fin gaps are arranged along the height direction of the heat exchanger. The heat exchanger includes multiple heat exchange sections, which are arranged along the height of the heat exchanger; the fin clearance of the heat exchange section near the lower end of the heat exchanger is larger than that of the heat exchange section near the upper end of the heat exchanger.

[0006] In this technical solution, the heat exchanger is divided into multiple heat exchange sections along its height, with the lower sections having larger fin gaps and the upper sections having smaller fin gaps. This effectively solves the problem of uneven airflow distribution caused by the fan position in top-discharge outdoor units. In the upper part of the heat exchanger, where airflow velocity is high, the smaller fin gaps ensure sufficient heat exchange area, fully utilizing the higher airflow velocity to improve heat exchange efficiency. Conversely, in the lower part of the heat exchanger, where airflow velocity is low, larger fin gaps reduce airflow resistance and improve airflow at the lower end, thus improving the heat exchange effect at the bottom of the heat exchanger. This differentiated fin gap design balances the conflict between the heat exchange area and air resistance in each heat exchange section, resulting in more uniform heat exchange performance along the height of the heat exchanger. This reduces material costs without compromising the overall heat exchange efficiency or unit performance.

[0007] In some embodiments of this application, the heat exchanger includes a connecting piece located at a corner of the heat exchanger, the connecting piece being arranged along the height direction of the casing, and the connecting piece being connected to multiple heat exchange sections.

[0008] In this technical solution, connecting plates extending along the height of the casing are installed at the corners of the heat exchanger, connecting the plates to multiple heat exchange sections to increase the structural integrity and stability of the heat exchanger. Since the heat exchanger adopts a multi-section design, relative displacement or uneven stress may occur among the heat exchange sections during installation and operation. The connecting plates securely connect the multiple heat exchange sections into a whole, ensuring accurate relative positioning of each section and preventing fin gap misalignment due to structural loosening. This ensures that the differentiated fin gap design can fully function. Simultaneously, the connecting plates, located at the corners and along the height direction, do not significantly obstruct the airflow entering through the air inlet, and do not affect the airflow efficiency in each heat exchange section. While ensuring structural reliability, this maintains the heat exchanger's heat exchange performance, providing structural support for the stable operation of the multi-section heat exchanger.

[0009] Secondly, this application provides a design method for a heat exchanger, used to design the aforementioned heat exchanger; the design method includes the following steps: Select an initial heat exchanger to be optimized. The fin gaps of the initial heat exchanger are the same, and the initial heat exchanger is a single segment in its height direction. The fan was operated at its rated power, and a fluid dynamics simulation was performed on the initial heat exchanger to obtain the flow velocity at different positions along the height direction of the initial heat exchanger. Based on the height and flow velocity distribution of the initial heat exchanger, the initial heat exchanger is divided into multiple heat exchange sections and the fin gap of each heat exchange section is determined to obtain a multi-section heat exchanger. The fan was restarted at its rated power, and a fluid dynamics simulation was performed on the multi-stage heat exchanger to obtain the flow velocity in each heat exchange stage of the multi-stage heat exchanger. The flow velocity of each heat exchange section in the multi-stage heat exchanger is obtained, the heat exchange capacity of each heat exchange section is calculated, and the heat exchange capacity of multiple heat exchange sections is superimposed to obtain the heat exchange capacity of the multi-stage heat exchanger. If the heat exchange capacity of the multi-stage heat exchanger is greater than that of the initial heat exchanger, then the multi-stage heat exchanger is the final heat exchanger. If the heat exchange capacity of the multi-stage heat exchanger is less than or equal to that of the initial heat exchanger, the fin clearance of the corresponding heat exchange section is adjusted again according to the flow velocity and fin clearance of each heat exchange section in the multi-stage heat exchanger to optimize the multi-stage heat exchanger. Then, a fluid dynamics simulation is performed on the optimized multi-stage heat exchanger to calculate and compare the heat exchange capacity of the optimized multi-stage heat exchanger with that of the initial heat exchanger, until a multi-stage heat exchanger with a heat exchange capacity stronger than the initial heat exchange capacity is obtained.

[0010] In this technical solution, the number of heat exchanger segments and the fin clearance of each segment are optimized through fluid dynamics simulation and iterative optimization to increase the overall heat exchange efficiency of the heat exchanger in the top-discharge air conditioning indoor unit. First, by simulating the velocity distribution of the initial single-segment heat exchanger, the airflow characteristics at different heights of the heat exchanger are accurately understood, providing data support for segment design and determination of the initial fin clearance, avoiding the problems of blind segmentation and clearance setting. Second, through multiple simulations, drag coefficient calculations, heat exchange capacity comparisons, and iterative adjustments, the fin clearance of each heat exchange segment can be continuously optimized, effectively balancing the contradiction between heat exchange area and air resistance, ensuring that the heat exchange capacity of the final multi-segment heat exchanger is superior to that of the initial single-segment heat exchanger. This method specifically solves the problem of uneven heat exchange at the upper and lower ends of the heat exchanger in the top-discharge outdoor unit. By adjusting the fin clearance of each heat exchange segment as needed, the design of each heat exchange segment is adapted to its corresponding velocity environment, thereby improving the overall heat exchange efficiency of the heat exchanger.

[0011] In some embodiments of this application, multiple multi-stage heat exchangers with stronger heat exchange capacity than the initial heat exchanger can be obtained based on different fin gaps. Optimization is performed on these multiple multi-stage heat exchangers to determine the final heat exchanger. The optimization method includes the following steps: Calculate the heat exchange area and heat exchange capacity of each multi-stage heat exchanger; Establish the objective function for heat exchange area and heat exchange capacity; Select the heat exchanger with the maximum objective function from among multiple multi-stage heat exchangers as the final heat exchanger.

[0012] In the technical solution, the size of the heat exchange area is related to the material cost of the heat exchanger. By establishing an objective function of heat exchange area and heat exchange capacity, and selecting the heat exchanger with the maximum value of the objective function as the final heat exchanger, it is possible not only to ensure that the heat exchange capacity of the final heat exchanger is better than that of the initial heat exchanger, but also to achieve the optimal balance between heat exchange performance and heat exchange area. This avoids the cost waste caused by excessively increasing the heat exchange area in pursuit of heat exchange capacity, and also avoids the problem of affecting the heat exchange effect due to excessive control of the heat exchange area.

[0013] In some embodiments of this application, the resistance coefficient of each heat exchange section and the heat exchange area of ​​each heat exchange section are determined according to the fin gap; the heat exchange capacity of the heat exchanger is calculated according to the resistance coefficient and heat exchange area of ​​the heat exchange section. Adjust the fin clearance of the heat exchanger according to the flow rate and resistance coefficient of the heat exchanger.

[0014] In some embodiments of this application, the height of the initial heat exchanger is determined based on the height of the casing and the height of the fan; the height of the final heat exchanger is the same as the height of the initial heat exchanger.

[0015] In the technical solution, the initial height is determined based on the height of the casing and the fan, and the final height of the heat exchanger is the same as the initial height of the heat exchanger, so that the optimized heat exchanger can be directly integrated into the outdoor unit without modifying the casing or fan layout.

[0016] In some embodiments of this application, when performing fluid dynamics simulation on the heat exchanger, the positional relationship between the fan and the heat exchanger is the same as the positional relationship between the fan and the heat exchanger in the outdoor unit of a top-discharge air conditioner.

[0017] In the technical solution, the positional relationship between the fan and the heat exchanger is made the same as the actual positional relationship in the outdoor unit of the top-discharge air conditioner, so as to ensure that the simulation conditions truly reflect the actual operating environment, more accurately predict air flow and heat exchange behavior, and reduce design errors.

[0018] In some embodiments of this application, the flow velocity at the lower end of the final heat exchanger is greater than the flow velocity at the lower end of the initial heat exchanger.

[0019] In some embodiments of this application, the height of each heat exchange section in the final heat exchanger is not exactly the same; during the design process, the height of the heat exchange section remains constant.

[0020] In some embodiments of this application, the flow rate of the heat exchanger is the flow rate at the centerline of the heat exchanger in the thickness direction.

[0021] In the above embodiments, the heat exchanger is designed using fluid dynamics simulation and iterative optimization to include multiple heat exchange sections. The fin gaps of the heat exchange sections are optimized so that the lower heat exchange section has a larger fin gap and the upper heat exchange section has a smaller fin gap. This effectively solves the problem of uneven airflow distribution caused by the fan position in top-discharge outdoor units, balances the contradiction between the heat exchange area of ​​each heat exchange section and the air resistance, and makes the heat exchange performance of the heat exchanger more uniform in the height direction. This reduces material costs without reducing the overall heat exchange efficiency and overall unit performance of the heat exchanger. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the structure of one embodiment of the top-discharge air conditioner outdoor unit in this application; Figure 2 This is a schematic diagram of the internal structure of an embodiment of the top-discharge air conditioner outdoor unit in this application; Figure 3 This is a schematic diagram of the airflow path in the outdoor unit of a top-discharge air conditioner in related technologies; Figure 4 This is a structural schematic diagram of a single-stage heat exchanger in related technologies; Figure 5 This is a schematic diagram of the surface air inlet velocity of a single-stage heat exchanger in related technologies; Figure 6 This is a schematic diagram illustrating the relationship between fin clearance and fin resistance in related technologies; Figure 7 This is a schematic diagram of the heat exchanger structure in one embodiment of the top-discharge air conditioner outdoor unit in this application; Figure 8 This is a flowchart of the design method for the heat exchanger in this application; Figure 9 This is a flowchart of the optimization process for multiple multi-stage heat exchangers in this application; Figure 10 This is a schematic diagram of the surface airflow velocity of the heat exchanger in one embodiment of the top-discharge air conditioner outdoor unit in this application.

[0023] In the diagram, 100 is the casing; 200 is the fan; 300 is the heat exchanger; 400 is the compressor; and 500 is the connecting plate. 101. Air inlet; 102. Air outlet. Detailed Implementation

[0024] To make the objectives and implementation methods of this application clearer, the exemplary implementation methods of this application will be clearly and completely described below with reference to the accompanying drawings of the exemplary embodiments of this application. Obviously, the exemplary embodiments described are only some embodiments of this application, and not all embodiments.

[0025] It should be noted that the brief descriptions of terms in this application are only for the convenience of understanding the embodiments described below, and are not intended to limit the embodiments of this application. Unless otherwise stated, these terms should be understood in their ordinary and common meaning.

[0026] The terms "first," "second," "third," etc., used in the specification, claims, and accompanying drawings of this application are used to distinguish similar or related objects or entities, and do not necessarily imply a specific order or sequence, unless otherwise specified. It should be understood that such terms are interchangeable where appropriate.

[0027] The terms “comprising” and “having”, and any variations thereof, are intended to cover but not exclude inclusion, for example, a product or device that includes a range of components is not necessarily limited to all of the components that are clearly listed, but may include other components that are not clearly listed or that are inherent to such product or device.

[0028] The top-discharge air conditioner outdoor unit provided in this application can have various implementation forms. Figures 1-2 This is a specific embodiment of the top-discharge air conditioner outdoor unit of this application.

[0029] like Figures 1-2 As shown, the top-discharge air conditioner outdoor unit provided in this application includes a housing 100. The housing 100 forms the overall appearance of the air conditioner outdoor unit. The top and bottom of the housing 100 are opposite ends, and the direction from the top to the bottom of the housing 100 is the height direction of the housing 100. The left and right sides of the housing 100 are opposite sides, and the direction from the left to the right side of the housing 100 is the width direction of the housing 100. The front and rear sides of the housing 100 are opposite sides, and the direction from the front to the rear side of the housing 100 is the thickness direction of the housing 100.

[0030] like Figure 1 As shown, the housing 100 includes an air inlet 101, which is located on the side of the housing 100, and outdoor air enters the interior of the housing 100 through the air inlet 101.

[0031] like Figure 1As shown, the housing 100 includes an air outlet 102, which is located on the top of the housing 100 and faces upward. Air inside the housing 100 is output to the outside through the air outlet 102.

[0032] like Figure 1 As shown, the top-discharge air conditioner outdoor unit includes a fan 200, which is located inside the casing 100 and positioned near the air outlet 102. With the operation of the fan 200, outdoor air enters the casing 100 through the air inlet 101, comes into contact with the heat exchanger 300, and is then discharged to the outside through the air outlet 102.

[0033] In some embodiments, the fan 200 is an axial flow fan 200, and the fan 200 is located below the air outlet 102.

[0034] like Figure 2 As shown, the top-discharge air conditioner outdoor unit includes a compressor 400, which is located inside the casing 100 and mounted at the bottom of the casing 100, below the fan 200. The compressor 400 is used to compress the low-temperature, low-pressure refrigerant into a high-temperature, high-pressure state.

[0035] like Figure 2 As shown, the top-discharge air conditioner outdoor unit includes a heat exchanger 300, which is located inside the casing 100 and is used to exchange heat with the air inside the casing 100. The heat exchanger 300 is located near the air inlet 101, with the windward side of the heat exchanger 300 facing the air inlet 101 and the leeward side of the heat exchanger 300 facing the compressor 400. The heat exchanger 300 is mounted on the bottom surface of the casing 100.

[0036] The heat exchanger 300 extends along the periphery of the casing 100 in its longitudinal direction to maximize the area of ​​the heat exchanger 300 within the same space, thereby increasing the heat exchange efficiency of the heat exchanger 300. The compressor 400 is located on the leeward side of the heat exchanger 300.

[0037] like Figure 2 As shown, the heat exchanger 300 is located on the outer edge of the bottom surface of the housing 100, and the compressor 400 is located in the middle part of the bottom surface of the housing 100. The heat exchanger 300 extends along the inner wall of the housing 100 in the length direction to form a semi-enclosed structure. The heat exchanger 300 surrounds the compressor 400. On the one hand, this can increase the area of ​​the heat exchanger 300, thereby increasing the heat exchange effect of the heat exchanger 300. On the other hand, it can make the heat exchanger 300 close to the air inlet 101 so that the air entering the housing 100 can come into contact with the heat exchanger 300 in time, thereby increasing the heat exchange effect of the heat exchanger 300.

[0038] In some embodiments, the heat exchanger 300 is of type G or type C.

[0039] like Figure 4 As shown, the heat exchanger 300 is a finned heat exchanger 300; the heat exchanger 300 includes a plurality of fins, which are arranged along the length direction of the heat exchanger 300, and there are fin gaps between adjacent fins for airflow to pass through, so that air outside the housing 100 can enter the housing 100 through the air inlet 101 and the fin gaps; the length direction of the fin gaps is set along the height direction of the heat exchanger 300, and the width direction of the fin gaps is set along the length direction of the heat exchanger 300. For ease of description, the dimension of the fin gap in the fin arrangement direction is called the width dimension of the fin gap; the dimension of the fin gap in the 300 height direction of the heat exchanger is called the length dimension of the fin gap.

[0040] It should be noted that the height direction of the heat exchanger 300 is the same as that of the casing 100.

[0041] Because the fan 200 is located at the top of the casing 100, the upper end of the heat exchanger 300 is closer to the fan 200, while the lower end is farther away. This results in a higher inlet air velocity at the upper end of the heat exchanger 300 and a lower inlet air velocity at the lower end. Since the inlet air velocity directly affects the heat exchange performance of the heat exchanger 300, this uneven distribution of air velocity between the upper and lower ends of the heat exchanger 300 leads to poor heat exchange performance at the lower part of the heat exchanger 300, preventing it from fully realizing its designed performance.

[0042] like Figure 5 As shown, the wind speed difference between the upper and lower ends of the heat exchanger 300 gradually increases as the height of the heat exchanger 300 increases, resulting in a significant difference in heat exchange performance between the upper and lower ends of the heat exchanger 300.

[0043] In related technologies, the fin gap is the same in the fin arrangement direction. Under the same fin gap condition, the lower the wind speed, the greater the air flow resistance of the fins. This makes the resistance of air passing through the lower end of the heat exchanger 300 greater than the resistance passing through the upper end of the heat exchanger 300. This phenomenon further aggravates the attenuation of the heat exchange performance of the lower part of the heat exchanger 300.

[0044] In related technologies, without considering the influence of other factors, the heat exchange capacity of a heat exchanger is positively correlated with the heat exchange area and the inlet air velocity. The larger the heat exchange area, the stronger the heat exchange capacity; the smaller the heat exchange area, the weaker the heat exchange capacity; the higher the inlet air velocity, the stronger the heat exchange capacity; the lower the inlet air velocity, the weaker the heat exchange capacity.

[0045] It can be considered that the heat exchange capacity of a heat exchanger is a function of the heat exchange area and the air velocity. That is, the functional expression for calculating the heat exchange capacity of a heat exchanger can be simplified as: Q=f(Y,V), where Q is the heat exchange capacity of the heat exchanger, Y is the heat exchange area of ​​the fins, and V is the inlet air velocity.

[0046] Without considering the influence of other factors, the inlet air velocity of a heat exchanger is related to the fin gap and fin resistance. The larger the fin gap, the higher the inlet air velocity; the smaller the fin gap, the lower the inlet air velocity; the greater the fin resistance, the lower the inlet air velocity; and the smaller the fin resistance, the higher the inlet air velocity.

[0047] It can be considered that the inlet air velocity of the heat exchanger is a function of the fin gap and the fin resistance, that is, the functional expression of the inlet air velocity is: V=f(S,K), where S is the fin gap of the heat exchanger and K is the fin ventilation resistance coefficient.

[0048] It should be noted that the higher the drag coefficient of the fin ventilation, the greater the resistance of the fin to the airflow; conversely, the lower the drag coefficient of the fin ventilation, the less resistance of the fin to the airflow. For ease of explanation, the resistance of the fin to the airflow is referred to as fin drag.

[0049] The heat exchange area of ​​a heat exchanger is negatively correlated with the fin gap; the larger the fin gap, the smaller the heat exchange area; the smaller the fin gap, the larger the heat exchange area.

[0050] It can be considered that the heat exchange area of ​​the heat exchanger is a function of the fin gap, and the functional expression of the heat exchange area is: Y=f(S), where Y is the heat exchange area of ​​the heat exchanger; S is the fin gap of the heat exchanger.

[0051] As can be seen from the above analysis, the heat exchange capacity of a heat exchanger is related to the fin gap and fin resistance. That is, the functional expression for calculating the heat exchange capacity can be simplified to Q=f(S,K).

[0052] like Figure 6 As shown, the larger the fin gap, the smaller the fin drag; the smaller the fin gap, the greater the fin drag. Fin gap and fin drag are negatively correlated.

[0053] Based on this, this application designs the heat exchanger 300 into multiple heat exchange sections in the height direction, with the lower heat exchange section having a larger fin gap and the upper heat exchange section having a smaller fin gap. This effectively solves the problem of uneven air distribution caused by the position of the fan 200 in the top-discharge outdoor unit, making the heat exchange performance of the heat exchanger 300 more uniform in the height direction, improving the overall heat exchange efficiency of the heat exchanger 300, and thus improving the overall heat exchange performance of the outdoor unit.

[0054] like Figure 7 As shown, the heat exchanger 300 includes multiple heat exchange sections, which are arranged along the height direction of the heat exchanger 300; the fin gaps on different heat exchange sections are different, and the fin gaps of the lower heat exchange sections are larger than those of the upper heat exchange sections.

[0055] In the upper part of heat exchanger 300, where airflow velocity is high, a smaller fin gap ensures sufficient heat exchange area to fully utilize the higher airflow velocity and improve heat exchange efficiency. Conversely, in the lower part of heat exchanger 300, where airflow velocity is low, a larger fin gap reduces airflow resistance, thereby increasing the airflow velocity at the lower end of heat exchanger 300 and improving airflow at the lower end, thus enhancing the heat exchange effect. This differentiated fin gap design balances the conflict between heat exchange area and air resistance in each heat exchange section, resulting in more uniform heat exchange performance of heat exchanger 300 along its height, avoiding localized overheating and energy loss, improving the overall heat exchange efficiency of heat exchanger 300, and consequently enhancing the overall heat exchange performance of the outdoor unit.

[0056] like Figure 7 As shown, the heat exchanger 300 includes a connecting piece 500, which is located at the corner of the heat exchanger 300. The connecting piece 500 is arranged along the height direction of the casing 100 and is connected to multiple heat exchange sections.

[0057] By installing connecting plates 500 extending along the height of the casing 100 at the corners of the heat exchanger 300, the connecting plates 500 are connected to multiple heat exchange sections, thereby increasing the structural integrity and stability of the heat exchanger 300. Since the heat exchanger 300 adopts a multi-section design, relative displacement or uneven stress may occur among the heat exchange sections during installation and operation. The connecting plates 500 securely connect the multiple heat exchange sections into a whole, ensuring accurate relative positions of each section and preventing fin gap misalignment due to structural loosening, thus ensuring the differentiated fin gap design can fully function. Simultaneously, the connecting plates 500, located at the corners and extending along the height, do not significantly obstruct the airflow entering through the air inlet 101, and do not affect the airflow efficiency in each heat exchange section. While ensuring structural reliability, this maintains the heat exchange performance of the heat exchanger 300, providing structural support for the stable operation of the multi-section heat exchanger 300.

[0058] It should be noted that the heat exchanger 300 is provided with connecting plates 500 on the windward and leeward sides to increase the connection effect of the connecting plates 500 on multiple heat exchange sections.

[0059] It should also be noted that each connecting piece 500 can be a single piece or a segmented piece that matches the segmented heat exchanger. If the connecting piece 500 is segmented, an additional structure is required to connect the segmented connecting pieces into a single piece.

[0060] For ease of description and understanding, the heat exchanger comprising multiple heat exchange sections in this application is referred to as a multi-section heat exchanger, while the heat exchanger in related technologies is referred to as a single-section heat exchanger.

[0061] It should be noted that the multi-stage heat exchanger in this application is the same as the single-stage heat exchanger in the related technology in terms of external dimensions and shape. In terms of mechanical structure, only the number of heat exchange sections and the fin gap are different.

[0062] Based on the above-mentioned top-discharge air conditioner outdoor unit, this application also provides a heat exchanger design method for designing the aforementioned heat exchanger; by selecting a single-stage heat exchanger with the same fin gap as the initial heat exchanger, the initial heat exchanger is optimized by using fluid dynamics simulation and iterative optimization to obtain a multi-stage variable gap heat exchanger, thereby increasing the overall heat exchange efficiency of the heat exchanger in the top-discharge air conditioner indoor unit.

[0063] Specifically, such as Figure 8 As shown, the design method for a heat exchanger includes the following steps: Select an initial heat exchanger to be optimized. The fin gaps of the initial heat exchanger are the same, and the initial heat exchanger is a single segment in its height direction. The fan was operated at its rated power, and a fluid dynamics simulation was performed on the initial heat exchanger to obtain the flow velocity at different positions along the height direction of the initial heat exchanger. Based on the height and flow velocity distribution of the initial heat exchanger, the initial heat exchanger is divided into multiple heat exchange sections and the fin gap of each heat exchange section is determined to obtain a multi-section heat exchanger. The fan was restarted at its rated power, and a fluid dynamics simulation was performed on the multi-stage heat exchanger to obtain the flow velocity in each heat exchange stage of the multi-stage heat exchanger. The flow velocity of each heat exchange section in the multi-stage heat exchanger is obtained, the heat exchange capacity of each heat exchange section is calculated, and the heat exchange capacity of multiple heat exchange sections is superimposed to obtain the heat exchange capacity of the multi-stage heat exchanger. Compare the heat exchange capacity of a multi-stage heat exchanger with that of a primary heat exchanger; If the heat exchange capacity of the multi-stage heat exchanger is greater than that of the initial heat exchanger, then the multi-stage heat exchanger is the final heat exchanger. If the heat exchange capacity of the multi-stage heat exchanger is less than or equal to that of the initial heat exchanger, the fin clearance of the corresponding heat exchange section is adjusted again according to the flow velocity and fin clearance of each heat exchange section in the multi-stage heat exchanger to optimize the multi-stage heat exchanger. Then, a fluid dynamics simulation is performed on the optimized multi-stage heat exchanger to calculate and compare the heat exchange capacity of the optimized multi-stage heat exchanger with that of the initial heat exchanger, until a multi-stage heat exchanger with a heat exchange capacity stronger than the initial heat exchange capacity is obtained.

[0064] In this application, the flow velocity distribution of the initial heat exchanger is first simulated to accurately grasp the airflow characteristics at different heights of the heat exchanger, providing data support for the segmented design and determination of the initial fin gap, thus avoiding the problems of blind segmentation and gap setting. Then, through multiple simulations, heat exchange capacity comparisons, and iterative adjustments, the fin gap of each heat exchange segment is continuously optimized to effectively balance the contradiction between heat exchange area and air resistance, ensuring that the heat exchange capacity of the final multi-segment heat exchanger is better than that of the initial single-segment heat exchanger, effectively solving the problem of uneven heat exchange at the upper and lower ends of the heat exchanger in the top-discharge outdoor unit.

[0065] It should be noted that, depending on the height of the initial heat exchanger, the heat exchange section may be divided into two heat exchange sections, three heat exchange sections, or even four or five heat exchange sections.

[0066] In some embodiments, when the wind speed is greater than a first set value, the initial fin gap is a first threshold value; when the wind speed is less than or equal to the first set value, the ratio between the initial fin gap and the first threshold value is equal to the ratio between the wind speed and the first set value.

[0067] It should be noted that the method of determining the initial fin gap of the heat exchange section based on the wind speed and the fin gap of the integrated heat exchanger is a conventional technique in this field and will not be elaborated here.

[0068] It should also be noted that the heat exchange capacity of current multi-stage heat exchangers is greater than that of the initial heat exchanger. Even after readjusting the fin gaps based on the heat exchange sections, air velocity, and fin gaps in the current multi-stage heat exchanger, the heat exchange capacity of the multi-stage heat exchanger may still be greater than that of the initial heat exchanger. Therefore, it can be concluded that there are many multi-stage heat exchangers with a heat exchange capacity greater than that of the initial heat exchanger.

[0069] The fin gaps in the heat exchange sections can have different values, thus resulting in multiple multi-stage heat exchangers. At least some of these multi-stage heat exchangers have a higher heat exchange capacity than the initial heat exchanger, but there are significant differences in heat exchange performance among these multi-stage heat exchangers with better heat exchange performance than the initial heat exchanger. In this application, the final heat exchanger is determined by optimizing multiple multi-stage heat exchangers with different fin gaps.

[0070] like Figure 9 As shown, the optimization method includes the following steps: Calculate the heat exchange area and heat exchange capacity of each multi-stage heat exchanger; Establish the objective function for heat exchange area and heat exchange capacity; Select the heat exchanger with the maximum objective function from among multiple multi-stage heat exchangers as the final heat exchanger.

[0071] It should be noted that the size of the heat exchange area is related to the material cost of the heat exchanger. The smaller the heat exchange area, the fewer the fins in the heat exchanger, and the lower the material cost of the heat exchanger.

[0072] In this application, by establishing an objective function for heat exchange area and heat exchange capacity, and selecting the heat exchanger corresponding to the maximum value of the objective function as the final heat exchanger, it is possible not only to ensure that the heat exchange capacity of the final heat exchanger is better than that of the initial heat exchanger, but also to achieve the optimal balance between heat exchange performance and heat exchange area. This avoids the cost waste caused by excessively increasing the heat exchange area in pursuit of heat exchange capacity, and also avoids the problem of affecting the heat exchange effect due to excessive control of the heat exchange area.

[0073] It should be noted that the resistance coefficient and heat transfer area of ​​each heat transfer section are determined based on the fin gap; the heat transfer capacity of the heat exchanger is calculated based on the resistance coefficient and heat transfer area of ​​the heat transfer section; and the heat transfer area of ​​the corresponding heat transfer section is obtained based on the fin gap and the height of the heat transfer section.

[0074] In some embodiments, some companies have databases of fin clearance and drag coefficients, and the drag coefficient can be found in the database based on the fin clearance. If the corresponding drag coefficient is not found in the database, it can be obtained experimentally and added to the database.

[0075] The initial heat exchanger height is determined based on the height of the casing and the height of the fan. The final heat exchanger height is the same as the initial heat exchanger height, so that the optimized heat exchanger can be directly integrated into the outdoor unit without modifying the casing or fan layout.

[0076] When performing fluid dynamics simulation on the heat exchanger, the positional relationship between the fan and the heat exchanger is the same as that between the fan and the heat exchanger in the outdoor unit of a top-discharge air conditioner. This ensures that the simulation conditions truly reflect the actual operating environment, more accurately predict airflow and heat exchange behavior, and reduce design errors.

[0077] The flow velocity at the bottom of the final heat exchanger is greater than that at the bottom of the initial heat exchanger, and the fin clearance at the bottom of the final heat exchanger is greater than that at the bottom of the initial heat exchanger.

[0078] It should be noted that the fin gap at the top of the final heat exchanger can be the same as or different from the fin gap at the top of the initial heat exchanger.

[0079] In a multi-stage heat exchanger, the height of each heat exchange stage is not exactly the same; the final height of the heat exchange stage in the heat exchanger is the same as the height of the corresponding heat exchange stage in the multi-stage heat exchanger.

[0080] In some embodiments, the flow rate of the heat exchanger is the flow rate of the central layer of the heat exchanger in the thickness direction.

[0081] It should be noted that the flow velocity in the heat exchanger can be either the velocity on the inlet surface or the velocity on the outlet surface. The velocity with the smaller data error is selected as the preferred velocity, but it must be consistent with the initial heat exchanger velocity sampling point and sampling location.

[0082] It should be noted that the location of the wind speed selection point remains unchanged during the design process to ensure the accuracy of the design.

[0083] In this application, the heat exchanger is designed using fluid dynamics simulation and iterative optimization to include multiple heat exchange sections. The fin gaps of the heat exchange sections are optimized, resulting in larger fin gaps in the lower heat exchange sections and smaller fin gaps in the upper heat exchange sections. This effectively solves the problem of uneven airflow distribution caused by the fan position in top-discharge outdoor units, balances the contradiction between the heat exchange area of ​​each heat exchange section and air resistance, and makes the heat exchange performance of the heat exchanger more uniform in the height direction. This reduces material costs without reducing the overall heat exchange efficiency and overall unit performance of the heat exchanger.

[0084] The design method of the above-mentioned heat exchanger is described in detail below, taking a heat exchanger consisting of three heat exchange sections as an example.

[0085] The design methodology for heat exchangers includes the following steps: A single-stage heat exchanger with a fin gap of δ0 and a height of H is selected as the initial heat exchanger. The fan was operated at its rated power, and a fluid dynamics simulation was performed on the initial heat exchanger to obtain the flow velocity at different locations of the initial heat exchanger. The initial heat exchanger is divided into three heat exchange sections to obtain a multi-section heat exchanger. The three heat exchange sections are, from top to bottom, the first heat exchange section, the second heat exchange section, and the third heat exchange section. The initial fin gap is determined according to the flow velocity at the corresponding position in the initial heat exchanger for each heat exchange section. The height of the first heat exchange section is H1, and the fin gap is δ1; the height of the second heat exchange section is H2, and the fin gap is δ2; the height of the third heat exchange section is H3, and the fin gap is δ3. The fan was restarted at its rated power, and fluid dynamics simulations were performed on multiple multi-stage heat exchangers to obtain the flow velocities at different locations in the multi-stage heat exchangers. This allowed the flow velocities of the first, second, and third heat exchange sections in the multiple multi-stage heat exchangers to be obtained respectively.

[0086] The heat exchange capacity of the first heat exchange section is calculated based on the resistance coefficient and fin clearance of the first heat exchange section; the heat exchange capacity of the second heat exchange section is calculated based on the resistance coefficient and fin clearance of the second heat exchange section; the heat exchange capacity of the third heat exchange section is calculated based on the resistance coefficient and fin clearance of the third heat exchange section; the heat exchange capacity of the three heat exchange sections is then superimposed to obtain the heat exchange capacity of the multi-section heat exchanger. Compare the heat exchange capacity of a multi-stage heat exchanger with that of an initial heat exchanger; If the heat exchange capacity of the multi-stage heat exchanger is greater than that of the initial heat exchanger, then the multi-stage heat exchanger meets the design requirements. If the heat exchange capacity of the multi-stage heat exchanger is less than or equal to that of the initial heat exchanger, the fin gap is adjusted according to the flow velocity and resistance coefficient of the heat exchange section to obtain an optimized multi-stage heat exchanger. The fan is then run at its rated power again, and a fluid dynamics simulation is performed on the optimized multi-stage heat exchanger. The heat exchange capacity of the optimized multi-stage heat exchanger is calculated and compared with that of the initial heat exchanger. The above steps are repeated until a multi-stage heat exchanger with a heat exchange capacity greater than that of the initial heat exchanger is obtained.

[0087] Based on the different values ​​of δ1, δ2, and δ3, multiple multi-stage heat exchangers can be obtained. Since there are multiple multi-stage heat exchangers, there must also be multiple heat exchangers that meet the design requirements. Optimization is performed on these multiple multi-stage heat exchangers to determine the final heat exchanger. The optimization method includes the following steps: Calculate the heat exchange area and heat exchange capacity of each multi-stage heat exchanger; Establish the objective function for heat exchange area and heat exchange capacity; Select the heat exchanger with the maximum objective function from among multiple multi-stage heat exchangers as the final heat exchanger.

[0088] like Figure 10 As shown in the figure below, the inlet air velocity distribution of the adjusted multi-stage heat exchanger is compared with that of the single-stage heat exchanger.

[0089] In this application, by increasing the fin gap at the bottom of the heat exchanger, the fin resistance is reduced, thereby increasing the air inlet velocity at the bottom of the heat exchanger, thus maintaining or improving the heat exchange capacity at the bottom of the heat exchanger, so that the capacity of the bottom of the heat exchanger can be better utilized; at the same time, the material cost of the heat exchanger can be reduced by reducing the amount of fins used.

[0090] In this application, multiple multi-stage heat exchangers that meet the design requirements are further optimized to determine the multi-stage heat exchanger with good heat exchange capacity and low material cost.

[0091] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

[0092] For ease of explanation, the above description has been provided in conjunction with specific embodiments. However, the above exemplary discussion is not intended to be exhaustive or to limit the embodiments to the specific forms disclosed above. Various modifications and variations can be obtained based on the above teachings. The selection and description of the above embodiments are for the purpose of better explaining the principles and practical applications, thereby enabling those skilled in the art to better utilize the described embodiments and various different variations of embodiments suitable for specific use considerations.

Claims

1. A top-discharge outdoor unit for an air conditioner, characterized in that, include: The housing includes an air outlet and an air inlet, the air outlet being located at the top of the housing and the air inlet being located on the side of the housing. A fan is disposed inside the housing, and the fan is positioned near the air outlet; A compressor is disposed within the housing and is located below the fan; A heat exchanger is disposed inside the housing, with the windward side of the heat exchanger facing the air inlet and the leeward side of the heat exchanger facing the compressor. The heat exchanger includes a plurality of fins, with fin gaps between adjacent fins for airflow to pass through; the fin gaps are arranged along the height direction of the heat exchanger. The heat exchanger includes multiple heat exchange sections, which are arranged along the height of the heat exchanger; the fin gap of the heat exchange section near the lower end of the heat exchanger is larger than the fin gap of the heat exchange section near the upper end of the heat exchanger.

2. The top-discharge outdoor unit of an air conditioner according to claim 1, characterized in that, The heat exchanger includes a connecting piece located at a corner of the heat exchanger and arranged along the height direction of the casing. The connecting piece is connected to multiple heat exchange sections.

3. A design method for a heat exchanger, characterized in that, A method for designing a heat exchanger as described in any one of claims 1-2; the design method of the heat exchanger includes the following steps: Select an initial heat exchanger to be optimized. The initial heat exchanger has the same fin clearance and is a single segment in its height direction. The fan is operated at its rated power, and a fluid dynamics simulation is performed on the initial heat exchanger to obtain the flow velocity at different positions along the height direction of the initial heat exchanger. Based on the height and flow velocity distribution of the initial heat exchanger, the initial heat exchanger is divided into multiple heat exchange sections and the fin gap of each heat exchange section is determined to obtain a multi-section heat exchanger. The fan is then restarted at its rated power, and a fluid dynamics simulation is performed on the multi-stage heat exchanger to obtain the flow velocity of each heat exchange stage in the multi-stage heat exchanger. The flow velocity of each heat exchange section in the multi-section heat exchanger is obtained, the heat exchange capacity of each heat exchange section is calculated, and the heat exchange capacity of multiple heat exchange sections is superimposed to obtain the heat exchange capacity of the multi-section heat exchanger. If the heat exchange capacity of the multi-stage heat exchanger is greater than that of the initial heat exchanger, then the multi-stage heat exchanger is the final heat exchanger. If the heat exchange capacity of the multi-stage heat exchanger is less than or equal to the heat exchange capacity of the initial heat exchanger, the fin clearance of the corresponding heat exchange section is adjusted again according to the flow velocity and fin clearance of each heat exchange section in the multi-stage heat exchanger to optimize the multi-stage heat exchanger. Then, a fluid dynamics simulation is performed on the optimized multi-stage heat exchanger to calculate and compare the heat exchange capacity of the optimized multi-stage heat exchanger with that of the initial heat exchanger, until a multi-stage heat exchanger with a heat exchange capacity stronger than that of the initial heat exchanger is obtained.

4. The design method of the heat exchanger according to claim 3, characterized in that, Based on the different fin gaps, multiple multi-stage heat exchangers with stronger heat exchange capabilities than the initial heat exchanger can be obtained. The multiple multi-stage heat exchangers are then optimized to determine the final heat exchanger. The optimization method includes the following steps: Calculate the heat exchange area and heat exchange capacity of each multi-stage heat exchanger; Establish the objective function for heat exchange area and heat exchange capacity; Select the heat exchanger with the maximum objective function from among multiple multi-stage heat exchangers as the final heat exchanger.

5. The heat exchanger design method according to claim 3, characterized in that, The resistance coefficient and heat exchange area of ​​each heat exchange section are determined based on the fin gap; the heat exchange capacity of the heat exchanger is calculated based on the resistance coefficient and heat exchange area of ​​the heat exchange section; and the fin gap of the heat exchanger is adjusted based on the flow velocity and resistance coefficient of the heat exchanger.

6. The design method of the heat exchanger according to claim 3, characterized in that, The height of the initial heat exchanger is determined based on the height of the casing and the height of the fan; the height of the final heat exchanger is the same as the height of the initial heat exchanger.

7. The design method for the heat exchanger according to claim 3, characterized in that, When performing fluid dynamics simulation on the heat exchanger, the positional relationship of the fan relative to the heat exchanger is the same as the positional relationship of the fan relative to the heat exchanger in the outdoor unit of the top-discharge air conditioner.

8. The design method of the heat exchanger according to claim 3, characterized in that, The flow velocity at the lower end of the final heat exchanger is greater than the flow velocity at the lower end of the initial heat exchanger.

9. The design method of the heat exchanger according to claim 3, characterized in that, The height of each heat exchange section in the final heat exchanger is not exactly the same; however, the height of the heat exchange section remains constant during the design process.

10. The design method of the heat exchanger according to claim 3, characterized in that, The flow rate in the heat exchanger is the flow rate in the central layer of the heat exchanger in the thickness direction.

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