Header assembly and use thereof

Abstract

The application belongs to the field of refrigeration technology and equipment, and particularly relates to a header assembly and application thereof. The existing micro-channel heat exchanger is not uniformly distributed with refrigerant. The application provides a header assembly, which comprises a head, a first header, a rotatable orifice plate and a second header connected in sequence, and an inner insert is arranged in the first header. The inner insert comprises a hollow pipe, the hollow pipe is communicated with the rotatable orifice plate through a partition plate, a plurality of independent cavities are arranged outside the hollow pipe, the independent cavities are communicated with micro-channel flat tubes, the number of the independent cavities is the same as that of the micro-channel flat tubes, the plurality of independent cavities are arranged in the first header, and each independent cavity is communicated with the first header. Two-phase refrigerant enters the rotatable orifice plate from the second header, and gas-liquid gradually mixes and flows. The uniformly mixed refrigerant enters the independent cavities after colliding with the head in the hollow pipe, and then enters the micro-channel flat tubes. The influence of gravity and phase separation is eliminated, and uniform distribution can be realized under different working conditions throughout the year.

Description

Technical Field

[0001] This application belongs to the field of refrigeration technology and equipment, and in particular relates to a manifold assembly and its application. Background Technology

[0002] The heat exchanger is an important component of a heat pump system. During year-round operation, the heat pump system can be divided into cooling and heating modes. Cooling mode includes rated cooling, intermediate cooling, and minimum cooling; heating mode includes rated heating, intermediate heating, and minimum heating.

[0003] When operating in summer cooling mode, the indoor heat exchanger functions as an evaporator; when operating in winter heating mode, the outdoor heat exchanger functions as an evaporator. When the heat exchanger is used as an evaporator, its inlet contains a two-phase refrigerant (gas and liquid). During the distribution of the two-phase refrigerant to each branch or channel, there is a serious problem of uneven distribution. Some channels contain less liquid refrigerant, resulting in "dry evaporation"; while others are rich in liquid refrigerant, resulting in "liquid carryover at the outlet." "Dry evaporation" prevents the full utilization of the heat exchange area, while "liquid carryover at the outlet" causes system fluctuations, which severely degrades system performance.

[0004] Microchannel heat exchangers are widely used in heat pump systems due to their excellent heat transfer performance, small charge requirements, and low cost. A microchannel heat exchanger mainly consists of a manifold and microchannel flat tubes, with the manifold distributing the two-phase refrigerant into the microchannel flat tubes. To address drainage and frosting issues, heat exchangers are typically placed vertically. However, the two-phase refrigerant within the vertical manifold is more prone to severe uneven distribution due to the combined effects of gravity and phase separation, leading to significant deterioration of system performance.

[0005] Furthermore, the different mass flow rates of the two-phase refrigerant at the evaporator inlet under rated, intermediate, and minimum operating conditions result in varying distribution characteristics. For instance, under rated conditions, due to the larger inlet mass flow rate of the two-phase refrigerant, the liquid refrigerant is more likely to reach the top of the microchannel heat exchanger, resulting in more liquid refrigerant in the upper channel and more gaseous refrigerant in the lower channel. However, under minimum operating conditions, the smaller inlet mass flow rate allows the liquid refrigerant to easily enter the lower channel under the influence of gravity, while the upper channel contains more gaseous refrigerant.

[0006] Existing microchannel heat exchangers typically use manifolds to distribute the two-phase refrigerant, which results in uneven refrigerant distribution. This is especially problematic when the heat exchanger is placed vertically, as the two-phase refrigerant within the vertical manifolds is affected by gravity and phase separation, making severe uneven distribution even more likely. Furthermore, they do not consider the issue of uniform refrigerant distribution under different operating conditions, failing to achieve uniform distribution across all operating conditions throughout the year. Summary of the Invention

[0007] 1. Technical problems to be solved

[0008] Existing microchannel heat exchangers typically use manifolds to distribute two-phase refrigerant, which results in uneven refrigerant distribution. This is especially problematic when the heat exchanger is placed vertically, as the two-phase refrigerant within the vertical manifold is affected by gravity and phase separation, making severe uneven distribution even more likely. Furthermore, the issue of uniform refrigerant distribution under different operating conditions is not considered, preventing the achievement of uniform distribution across all operating conditions throughout the year. This application provides a manifold assembly and its application.

[0009] 2. Technical Solution

[0010] To achieve the above objectives, this application provides a manifold assembly, comprising a head, a first manifold, a rotatable orifice plate, and a second manifold connected in sequence. The first manifold is provided with a plurality of microchannel flat tubes, and an inner insert is disposed within the first manifold. The inner insert includes a hollow tube, which communicates with the rotatable orifice plate via a partition. A plurality of independent cavities are disposed on the outer side of the hollow tube, and these independent cavities communicate with the microchannel flat tubes. The number of independent cavities is the same as the number of microchannel flat tubes. The plurality of independent cavities are disposed within the first manifold, and each independent cavity communicates with the first manifold. After the refrigerant enters the rotatable orifice plate from the second manifold, the gas and liquid gradually mix. The uniformly mixed refrigerant enters the hollow tube, impacts the head, and then enters the independent cavity and subsequently the microchannel flat tube.

[0011] Another embodiment provided in this application is: a plurality of vertical partitions and a plurality of horizontal partitions are provided on the outside of the hollow tube, and the plurality of vertical partitions and the plurality of horizontal partitions together with the inner wall of the first manifold form a plurality of independent cavities.

[0012] Another embodiment provided in this application is that the lengths of the vertical partitions are all different.

[0013] Another embodiment provided in this application is: the plurality of vertical partitions include a first vertical partition, and the length of the vertical partitions gradually increases in a clockwise direction with the first vertical partition as a reference.

[0014] Another embodiment provided in this application is: the horizontal partition is a fan-shaped partition, and the fan-shaped partition is provided with a plurality of through holes.

[0015] Another embodiment provided in this application is: the horizontal partition is a circular partition, and the circular partition is provided with a plurality of through holes, including circular through holes and fan-shaped through holes, the fan-shaped through holes gradually decreasing in size.

[0016] Another embodiment provided in this application is: the rotatable perforated plate is provided with an opening, the area of ​​which satisfies... and Where A is the orifice area, m is the refrigerant mass flow rate, mg is the gaseous mass flow rate in the refrigerant, and m l This represents the liquid phase mass flow rate in the refrigerant.

[0017] Another embodiment provided in this application is as follows: the rotatable orifice plate meshes with a gear, and the gear is connected to a motor; the motor drives the rotatable orifice plate to rotate, and the rotatable orifice plate cooperates with the partition plate to change the gas-liquid phase flow area; by adapting the gas-liquid phase flow area to the inlet mass flow rate under different working conditions, uniform distribution under different working conditions is achieved.

[0018] This application also provides an application of the aforementioned manifold assembly, wherein the manifold assembly, water outlet manifold, microchannel flat tube assembly, water inlet manifold, and refrigerant outlet manifold are connected in sequence.

[0019] Another embodiment provided in this application is: a microchannel heat exchanger containing the manifold assembly serves as the indoor and outdoor units of a heat pump system, and the refrigerant outlet manifold is connected to the compressor.

[0020] 3. Beneficial effects

[0021] Compared with the prior art, the beneficial effects of the manifold assembly and its application provided in this application are as follows:

[0022] The manifold assembly provided in this application is a vertical manifold assembly capable of achieving uniform distribution of refrigerant.

[0023] The manifold assembly provided in this application eliminates the effects of gravity and phase separation, enabling uniform distribution under different operating conditions throughout the year.

[0024] The application of the manifold assembly provided in this application enables the manifold assembly to be used in microchannel heat exchangers that can achieve uniform refrigerant distribution under different operating conditions, thereby improving the performance of the heat pump system, reducing the system's annual energy consumption, and ultimately increasing the annual APF of the heat pump system.

[0025] The application of the manifold assembly provided in this application, which is used in a water-cooled microchannel evaporator, has a small footprint and can achieve uniform and efficient heat exchange between the two-phase refrigerant and water, thus greatly improving the performance of the heat pump system. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the manifold assembly structure of this application;

[0027] Figure 2 This is a schematic diagram of the internal plug-in structure of this application;

[0028] Figure 3This is a schematic diagram of the horizontal partition structure of this application;

[0029] Figure 4 This is a schematic diagram of the independent cavity structure of this application;

[0030] Figure 5 This is a schematic diagram of the connection between the rotatable perforated plate, gear, and motor in this application;

[0031] Figure 6 This is a schematic diagram of the circulation area under different operating conditions in this application;

[0032] Figure 7 This is a schematic diagram of the microchannel heat exchanger of this application;

[0033] Figure 8 This is a schematic diagram of the application structure of the manifold component in this application;

[0034] Figure 9 This is a schematic diagram comparing the refrigerant distribution of the existing vertical manifold assembly (a) and the manifold assembly (b) of this application;

[0035] Figure 10 These are the volume fractions, vector diagrams, and trace diagrams of the gas and liquid phases of the manifold assembly of this application. Detailed Implementation

[0036] In the following, specific embodiments of this application will be described in detail with reference to the accompanying drawings. Based on these detailed descriptions, those skilled in the art will be able to clearly understand and implement this application. Without departing from the principles of this application, features from various embodiments can be combined to obtain new implementations, or certain features from some embodiments can be substituted to obtain other preferred implementations.

[0037] See Figures 1-10 This application provides a manifold assembly, including a head 5, a first manifold 3, a rotatable orifice plate 2, and a second manifold 1 connected in sequence. The first manifold 3 is provided with a plurality of microchannel flat tubes 6, and an inner insert 4 is provided inside the first manifold 3. The inner insert 4 includes a hollow tube 401, which is connected to the rotatable orifice plate 2 via a partition 427. A plurality of independent cavities are provided on the outside of the hollow tube 401, and these independent cavities are connected to the microchannel flat tubes 6. The number of independent cavities is the same as the number of microchannel flat tubes 6. The independent cavities are disposed within the first manifold 3, and each independent cavity is connected to the first manifold 3. A gas-liquid two-phase refrigerant of any flow pattern enters the rotatable orifice plate 2 from the second manifold 1, and the gas and liquid gradually mix. The refrigerant enters the hollow tube 401 for further uniform mixing, and then the uniformly mixed refrigerant impacts the head 5 and enters the independent cavity, subsequently entering the microchannel flat tube 6.

[0038] Specifically, the lower vertical manifold (i.e., the second manifold 1) and the upper vertical manifold (i.e., the first manifold 3) are connected to the rotatable orifice plate 2 via threads. Both the lower and upper vertical manifolds contain internal threads, while the rotatable orifice plate 2 contains external threads. This application describes a vertical manifold assembly capable of achieving uniform refrigerant distribution. The key to achieving uniform distribution lies in the inner insert 4. The principle is that the gas-liquid two-phase refrigerant entering from the lower vertical manifold first undergoes acceleration and decompression by the rotating orifice plate 2. The gas phase expands, and the liquid phase is broken into droplets, gradually mixing. Then, the mixed gas-liquid two-phase refrigerant enters the hollow tube 401 for further uniform mixing. The uniformly mixed gas-liquid two-phase refrigerant impacts the top end cap 5 and is evenly distributed into each independent cavity, with each independent cavity corresponding to a microchannel flat tube 6. The entire inner insert 4 is integrally formed by stamping, resulting in high consistency and low processing costs.

[0039] Furthermore, the hollow tube 401 is provided with several vertical baffles 411-416 and several horizontal baffles 421-427 on its outer side. These vertical baffles 411-416 and horizontal baffles 421-427, together with the inner wall of the first manifold 3, form several independent cavities. The upper vertical manifold contains an inner insert 4. The inner insert 4 is composed of the hollow tube 401, multiple levels of horizontal baffles 421-426, an inlet fixing orifice plate (baffle 427), and multiple levels of vertical baffles 411-416. The number of vertical baffles is equal to the number of microchannel flat tubes 6 (N), and the number of horizontal orifice plates is N+1. To ensure the mixing effect of the gas and liquid phases in the hollow tube 401, the diameter (d1) of the hollow tube 401 is preferably 4mm-7mm. Each independent cavity is formed by a corresponding combination of horizontal baffles 421-427 and vertical baffles 411-416. As shown in the figure, the number of horizontal partitions 421-427 and vertical partitions 411-416 are just examples. In specific applications, the number can be set according to the actual working conditions.

[0040] Furthermore, the lengths of the vertical partitions 411 to 416 are all different.

[0041] Furthermore, several of the vertical partitions 411-416 include a first vertical partition, and the length of the vertical partitions 411-416 gradually increases in a clockwise direction, based on the first vertical partition. For example... Figure 2 As shown, the lengths of the vertical partitions 411 to 416 are based on the first-stage vertical partition 411(L) near the microchannel flat tube 6 and gradually increase in a clockwise direction. The vertical partitions 412 to 416 are multiples of the first-stage vertical partition 411.

[0042] Furthermore, the horizontal partitions 421-427 are fan-shaped partitions, and the fan-shaped partitions are provided with several through holes. Here, the shape of the horizontal partitions 421-427 is not specific, as long as they can separate the cavities.

[0043] Furthermore, the horizontal partitions 421-427 are circular partitions, and each circular partition has several through holes, including circular through holes and fan-shaped through holes, with the fan-shaped through holes progressively smaller. For example... Figure 3 As shown, the multi-stage horizontal baffles 421-427 are divided into an inlet fixed perforation plate (baffle 427) and a progressively separating perforation plate (horizontal baffles 421-426). Horizontal baffles 421-426 mainly include a solid region 433, a circular hole flow region 431, and a fan-shaped flow region 432. The area (S1) of the solid region 433 gradually increases from the first to the sixth stage, while the area (S2) of the fan-shaped flow region 432 gradually decreases from the first to the sixth stage. The area (S3) of the circular hole flow region 431 remains constant, but the position of its circular holes changes clockwise. The number of circular holes in the circular hole flow region 431 can be 1 to 5, and the diameter of each circular hole is 1 mm to 2.5 mm. The inlet fixed perforation plate 427 is in the form of a large circle in the center surrounded by multiple small circular holes. The sum of the diameter (d2) of the large circular hole and the diameters (d3) of the two small circular holes is less than the diameter (d1) of the central tube 401. The number of small round holes can be 2, 4, or 6, and the diameter of the round holes is 1mm to 2mm.

[0044] like Figure 4 As shown, several independent cavities 41-46 are formed by two adjacent horizontal partitions 421-426 and vertical partitions 411-416, wherein the number of independent cavities is equal to the number of microchannel flat tubes 6. Horizontal partitions 421 and 422 and vertical partitions 416 and 411 form independent cavity 41; horizontal partitions 422 and 423 and vertical partitions 416 and 412 form independent cavity 42; horizontal partitions 423 and 424 and vertical partitions 416 and 413 form independent cavity 43; horizontal partitions 424 and 425 and vertical partitions 416 and 414 form independent cavity 44; horizontal partitions 425 and 426 and vertical partitions 416 and 415 form independent cavity 45; horizontal partition 426 and inlet orifice plate 427 form independent cavity 46.

[0045] Furthermore, the rotatable perforated plate is provided with an opening, the area of ​​which satisfies the following conditions: and Where A is the opening area, and m is the refrigerant mass flow rate. g The mass flow rate of the gas phase in the refrigerant is m. l This represents the liquid phase mass flow rate in the refrigerant.

[0046] Specifically, such as Figure 5As shown, the opening shape of the rotatable orifice plate 2 is the same as that of the inlet fixed orifice plate, i.e., partition 427. The thickness of the rotatable orifice plate 2 is 5 to 10 times that of the inlet fixed orifice plate. It consists of external threads at the top and bottom, and external teeth in the middle. It is connected to gear 21 and motor 22 through the external teeth. The rotation angle of the rotatable orifice plate 2 is controlled by motor 22. The rotatable orifice plate 2 meshes with gear 21; the motor 22 drives the rotatable orifice plate 2 to rotate, and the rotatable orifice plate 2 cooperates with partition 427 to change the gas-liquid phase flow area; by adapting the gas-liquid phase flow area to the inlet mass flow rate under different operating conditions, uniform distribution under different operating conditions is achieved.

[0047] The opening area A of the rotatable orifice plate 2 is determined by the refrigerant inlet mass flow rate m under rated operating conditions of the heat pump system. If the refrigerant mass flow rate under rated operating conditions is m, and the heat exchanger inlet dryness fraction x is typically 0.1–0.2, then the gas phase mass flow rate is m. g =m·x, where the liquid phase mass flow rate is m l = m·(1-x). The area of ​​the opening A must satisfy... and Under these conditions, the gas-liquid two-phase refrigerant can be uniformly mixed after passing through the rotatable orifice plate 2.

[0048] When the heat pump system operates under intermediate and minimum conditions, the gas-liquid phase flow areas A1 and A2 must be smaller than the orifice area A of the rotatable orifice plate under rated conditions. This can be achieved by driving the rotatable orifice plate 2 with a motor, superimposing the small orifice flow area around the rotatable orifice plate 2 onto the solid area of ​​the inlet fixed orifice plate 427, thereby reducing the gas-liquid phase flow area. If the refrigerant mass flow rates under intermediate and minimum conditions are m1 and m2 respectively, the relationship between the flow area and the refrigerant mass flow rate under different conditions is as follows:

[0049] By rotating the orifice plate 2 and the inner insert 4, the flow area of ​​the small holes around the rotatable orifice plate 2 is superimposed with the solid area of ​​the inlet fixed orifice plate, thereby adjusting the overall flow area of ​​the gas and liquid phases. By adapting the flow area of ​​the gas and liquid phases to the inlet mass flow rate, the refrigerant is evenly distributed under different operating conditions of the heat pump system, thereby improving the capacity of the heat pump system and reducing its energy efficiency.

[0050] The manifold assembly provided in this application can achieve uniform refrigerant distribution under different operating conditions. This vertical manifold assembly is integrally formed by stamping, which is simple in process and has low manufacturing costs.

[0051] This application also provides an application of the aforementioned manifold assembly, namely a microchannel heat exchanger; the manifold assembly, water outlet manifold 902, microchannel flat tube assembly, water inlet manifold 903, and refrigerant outlet manifold 904 are sequentially connected. This achieves uniform and efficient heat exchange between water and the two-phase refrigerant, and features a compact structure and small footprint. Applying it to the indoor and outdoor units of a heat pump system improves the system's performance, reduces system energy consumption, and thus increases the heat pump system's annual APF (Active Heat Flow Rate).

[0052] The microchannel flat tube assembly consists of a microchannel flat tube 601 for two-phase refrigerant flow and a microchannel flat tube 602 for water flow. The inlet pipe assembly consists of a refrigerant inlet elbow 801, a refrigerant outlet elbow 804, a water-side inlet elbow 803, and a water-side outlet elbow 802. The refrigerant inlet elbow 801 is connected to the refrigerant uniform vertical manifold assembly. The microchannel flat tube for refrigerant flow is vertically inserted into the vertical manifold assembly and the refrigerant outlet manifold 904, which is connected to the outlet elbow 804. The water inlet elbow 803 is connected to the water inlet manifold 903. The water-flowing microchannel flat tube 602 is vertically inserted into the water inlet manifold 903 and the water outlet manifold 902, which is connected to the water-side outlet elbow 802. The microchannel flat tubes 601 and 602 are brazed together.

[0053] like Figure 7 The microchannel heat exchanger shown achieves efficient heat exchange between water and two-phase refrigerant, as illustrated below. The two-phase refrigerant from the expansion valve of the heat pump system enters the inlet bend 801, and then, after passing through the vertical manifold assembly, is evenly distributed into the microchannel flat tubes 601. In the microchannel flat tubes 601, the refrigerant absorbs heat from the water in the two side microchannel flat tubes 602 and evaporates into a gaseous state. Finally, the gaseous refrigerant enters the compressor through the refrigerant outlet manifold 904. The even distribution of refrigerant in the vertical manifold improves heat exchange efficiency, avoids system oscillations caused by insufficient heat exchange and "liquid carryover" at the outlet, and significantly improves the performance of the heat pump system. Furthermore, the inlet pipe of this heat exchanger is a staggered bend, resulting in a compact structure and small footprint.

[0054] A microchannel heat exchanger with uniform refrigerant distribution is used as the indoor or outdoor unit of a heat pump system. When the heat pump system operates under rated, intermediate, and minimum operating conditions, the inlet refrigerant mass flow rates of the microchannel heat exchanger in the indoor or outdoor unit are m, m1, and m2, respectively. The mass flow rate m under rated conditions and the position of the rotatable orifice plate 2 are used as references (the position of the rotatable orifice plate 2 under rated conditions coincides with the inlet fixed orifice plate). When the inlet mass flow rate m is detected by the mass flow meter... i When m < m, the motor 22 drives the gear 21 to rotate, and the relationship between its rotation angle and the inlet mass flow rate is as follows: The value of k ranges from -1 to 0.

[0055] contrast Figure 9 (a) and Figure 9 (b) It can be seen that the vertical manifold assembly in this application can evenly distribute the refrigerant into each microchannel flat tube 6. From Figure 10 The vector and trace diagrams show that after the gas-liquid two-phase refrigerant is uniformly mixed in the hollow tube 401, it impacts the top end cap 5, then evenly disperses into each independent cavity, and subsequently is evenly distributed into each microchannel flat tube 6. From... Figure 10 The gas phase volume fraction diagram shows that the gas and liquid refrigerant are evenly distributed in the microchannel flat tube 6.

[0056] Although this application has been described above with reference to specific embodiments, those skilled in the art will understand that many modifications can be made to the configurations and details disclosed in this application within the principles and scope of the disclosure. The scope of protection of this application is determined by the appended claims, and the claims are intended to cover all modifications included in the literal meaning or scope of equivalents of the technical features in the claims.

Claims

1. A manifold assembly, characterized in that: The system comprises a head, a first manifold, a rotatable orifice plate, and a second manifold connected in sequence. The first manifold has several microchannel flat tubes and an inner insert, including a hollow tube, which communicates with the rotatable orifice plate via a partition. Several independent cavities are located outside the hollow tube and communicate with the microchannel flat tubes. The number of independent cavities is the same as the number of microchannel flat tubes. Several independent cavities are located within the first manifold, and each independent cavity communicates with the first manifold. Refrigerant enters the rotatable orifice plate from the second manifold and becomes a gas-liquid mixture. The uniformly mixed two-phase refrigerant enters the hollow tube, impacts the head, enters the independent cavities, and then enters the microchannel flat tubes. The hollow tube is provided with a number of vertical partitions and a number of horizontal partitions on its outer side. The number of vertical partitions and the number of horizontal partitions together with the inner wall of the first manifold form a number of independent cavities. The lengths of the vertical partitions are all different; The vertical partitions include a first vertical partition, and the length of the vertical partitions gradually increases in a clockwise direction, with the first vertical partition as a reference.

2. The manifold assembly as described in claim 1, characterized in that: The horizontal partition is a fan-shaped partition, and the fan-shaped partition is provided with several through holes.

3. The manifold assembly as described in claim 1, characterized in that: The horizontal partition is a circular partition with several through holes, including circular through holes and fan-shaped through holes, the fan-shaped through holes being progressively smaller.

4. The manifold assembly as claimed in claim 1, characterized in that: The rotatable perforated plate is provided with an opening, and the area of ​​the opening meets the following requirements. and ,in A The area of ​​the opening is... m g This represents the gaseous mass flow rate of the refrigerant. m l This represents the liquid phase mass flow rate in the refrigerant.

5. The manifold assembly as described in any one of claims 1 to 4, characterized in that: The rotatable orifice plate meshes with a gear, which is connected to a motor. The motor drives the rotatable orifice plate to rotate, and the rotatable orifice plate cooperates with the partition to change the gas-liquid phase flow area. By adapting the gas-liquid phase flow area to the inlet mass flow rate under different operating conditions, uniform distribution under different operating conditions is achieved.

6. An application of the manifold assembly according to any one of claims 1 to 5, characterized in that: The manifold assembly, water outlet manifold, microchannel flat tube assembly, water inlet manifold, and refrigerant outlet manifold are connected in sequence.

7. The application of the manifold assembly as described in claim 6, characterized in that: The microchannel heat exchanger containing the manifold assembly serves as the indoor and outdoor units of the heat pump system, and the refrigerant outlet manifold is connected to the compressor.

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