Micro-channel heat exchanger with adaptive adjustment of flat tube row number

Abstract

The application discloses a micro-channel heat exchanger capable of self-adapting to adjust the number of flat tubes, comprising two header pipes with flow guide openings, a plurality of flat tubes and fins arranged between the two header pipes, a self-adapting sealing assembly and a plurality of backflow prevention components arranged in the two header pipes and capable of being extended and contracted, the self-adapting sealing assembly is arranged in the header pipe to divide the header pipe into a medium cavity and an elastic cavity, the backflow prevention components are used for preventing the medium from flowing reversely from one end of the flat tube into the elastic cavity, and the height of the elastic cavity is contracted through the balance between the self-adapting sealing assembly and the medium pressure to change the volume of the medium cavity, so that the number of the flat tubes connected with the medium cavity is controlled. The number of the flat tubes participating in heat exchange can be automatically adjusted according to the size of the refrigerant inlet flow (pressure), the full-tube operation at high load and the few-tube operation at low load are realized, and thus the refrigerant is kept in the optimal flow speed range, the heat exchange efficiency and the system reliability under all working conditions are improved.

Description

Technical Field

[0001] This invention relates to the field of refrigeration and heat exchange equipment technology, specifically to a microchannel heat exchanger that can adaptively adjust the number of rows of flat tubes participating in heat exchange according to the refrigerant flow rate. Background Technology

[0002] Microchannel heat exchangers have been widely used in air conditioning and refrigeration systems due to their high efficiency and compact design. However, existing microchannel heat exchangers typically employ a fixed number of flat tube rows.

[0003] In actual operation, refrigeration and air conditioning systems face frequent load changes (e.g., from 100% full load to 20% low load). To meet peak load demands, existing microchannel heat exchange areas are typically matched to the system's peak high load conditions. While this design strategy ensures sufficient heat exchange capacity to meet user needs under peak conditions, it neglects the partial load conditions the equipment operates under for most of its operating time.

[0004] When the system is running at low load, the refrigerant flow rate decreases, the compressor frequency drops, and the refrigerant flowing through all the flat tube rows can cause the following problems: 1. When the system is under low load (low refrigerant flow), the existing fixed structure cannot dynamically adjust the number of flat tubes participating in heat exchange according to the flow rate. The refrigerant flows through a large number of flat tube rows, which slows down the flow velocity in a single flat tube, and may even cause laminar flow. This reduces the heat exchange efficiency, and the system energy efficiency ratio (COP) is low at low load, affecting the heat exchange performance.

[0005] 2. Under low-speed operation, the compressor speed is low and the refrigerant flow is small. If there are too many flat tubes, the flow rate will be too low, and the lubricating oil cannot be effectively carried back to the compressor, causing the compressor to wear or even burn out.

[0006] 3. If the flow rate is too low, the refrigerant bubbles at the wall will not easily detach from the surface, and will easily form a "vapor plug" in the flow channel, creating a dead zone in the flow.

[0007] Although there are existing technologies that use dual-row or multi-channel heat exchangers in conjunction with solenoid valves or electronic control systems to solve the partial load problem, this usually leads to a more complex system structure, increased costs, and a higher failure rate.

[0008] Therefore, there is an urgent need for a microchannel heat exchanger with a simple structure that can automatically adjust the heat exchange area according to the load without the need for external energy. Summary of the Invention

[0009] The purpose of this invention is to provide a microchannel heat exchanger with adaptive adjustment of the number of flat tube rows, which can automatically adjust the number of flat tube rows participating in heat exchange according to the refrigerant inlet flow rate (pressure), so as to achieve full tube row operation under high load and fewer tube rows operation under low load, thereby keeping the refrigerant within the optimal flow rate range and improving heat exchange efficiency and system reliability under all operating conditions.

[0010] To solve the aforementioned technical problems, this application adopts the following technical solution: A microchannel heat exchanger with adaptive adjustment of the number of flat tube rows includes two manifolds with flow guides, a plurality of flat tubes and fins disposed between the two manifolds, and each of the two manifolds is provided with a retractable adaptive sealing assembly and a plurality of anti-reverse members to prevent backflow at the outlet of the flat tubes. The manifolds are divided into a medium cavity and an elastic cavity by the adaptive sealing assembly. The anti-reverse members are located in the medium cavity to prevent the medium from flowing back into the elastic cavity from one end of the flat tube. The height of the elastic cavity contracts by the balance between the adaptive sealing assembly and the medium pressure to change the volume of the medium cavity, thereby controlling the number of flat tube rows communicating with the medium cavity.

[0011] Preferably, the adaptive sealing assembly includes a fixed sealing partition, a piston plate, and an elastic reset member. The two ends of the elastic cavity are sealed by the fixed sealing partition and the piston plate. The elastic reset member is disposed within the elastic cavity. The piston plate moves under the balance of the elastic force of the elastic reset member and the medium pressure to change the volume of the medium cavity, thereby controlling the number of rows of microchannel flat tubes communicating with the medium cavity.

[0012] Preferably, the manifold is provided with a vertical baffle, which divides the manifold into a first chamber communicating with the guide port and a second chamber communicating with the inlet and outlet of the flat tube. The adaptive sealing assembly is located in the first chamber. The second chamber is provided with several horizontal baffles, which divide the second chamber into several piston chambers. The vertical baffle is provided with a through hole communicating with the piston chamber. One side of the piston chamber is connected to the inlet and outlet of at least one of the flat tubes. The check valve is provided on the through hole.

[0013] Preferably, the adaptive sealing assembly is in its maximum compression state during its stroke range, and the medium cavity is connected to all of the flat tube rows.

[0014] The adaptive sealing assembly under maximum compression is located between two adjacent through holes.

[0015] Preferably, a sealing ring is provided between the piston plate and the vertical baffle.

[0016] Preferably, the elastic reset element is a spring, and the stiffness and preload of the spring are set according to the flow rate and pressure of the system design conditions.

[0017] Preferably, the anti-reverse component is located inside the medium cavity to prevent the medium from flowing back from the manifold to the microchannel flat tube.

[0018] Preferably, the check valve component is a one-way valve or a flap structure with a rotary connection.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows: Energy efficiency improvement: The heat exchange area is automatically adjusted according to the load, avoiding the deterioration of heat exchange at low flow rates under low load, and improving the overall energy efficiency ratio (COP) of the system.

[0020] Reliable structure: It adopts a pure mechanical structure, which does not require external power supply, electronic components or complex control algorithms, thus reducing cost and failure rate.

[0021] Rapid response: Driven by the refrigerant's own pressure, it can adjust in real time to follow load changes.

[0022] Improved oil return: Ensures refrigerant flow rate at low loads, which is beneficial for lubricant return and protects the compressor. Attached Figure Description

[0023] Figure 1 This is an initial state diagram of the adaptive sealing component in this invention; Figure 2 This is a micro-pressure state diagram of the adaptive sealing component in this invention; Figure 3 This is a schematic diagram of the adaptive sealing assembly in the maximum load state in this invention; In the diagram: 1. Medium chamber; 2. Anti-reverse component; 3. Manifold; 4. Elastic chamber; 5. Adaptive sealing assembly; 51. Piston plate; 52. Elastic reset component; 53. Fixed sealing partition; 6. Sealing ring; 7. Flat tube; 8. Fin; 9. Horizontal baffle; 10. Vertical baffle; 11. First chamber; 12. Second chamber; 13. Through hole; 14. Piston chamber. Detailed Implementation

[0024] The present application will now be further described in conjunction with the accompanying drawings and specific embodiments. It should be noted that, without conflict, the various embodiments or technical features described below can be arbitrarily combined to form new embodiments.

[0025] In the description of this application, it should be understood that the terms "upper", "lower", "left", "right", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application 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 this application.

[0026] The terms "first," "second," etc., used in this application are used to distinguish similar objects and not to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that embodiments of this application can be implemented in orders other than those illustrated or described herein, and the objects distinguished by "first," "second," etc., are generally of the same class, without limiting the number of objects; for example, a first object can be one or more. Furthermore, in the specification and claims, "and / or" indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0027] like Figures 1-3 As shown, a microchannel heat exchanger with adaptive adjustment of the number of flat tube rows includes two manifolds 3 with flow guides, a plurality of flat tubes 7 and fins 8 disposed between the two manifolds 3. Each of the two manifolds 3 is provided with a retractable adaptive sealing assembly 5 and a plurality of anti-reverse members 2 to prevent backflow at the outlet of the flat tubes 7. The manifolds 3 are divided into a medium cavity 1 and an elastic cavity 4 by the adaptive sealing assembly 5. The anti-reverse members 2 are located in the medium cavity 1 to prevent the medium from flowing back from one end of the flat tubes 7 into the elastic cavity 4. The height of the elastic cavity 4 is contracted by the balance between the adaptive sealing assembly 5 and the medium pressure to change the volume of the medium cavity 1, thereby controlling the number of rows of flat tubes 7 connected to the medium cavity 1.

[0028] The current microchannel heat exchanger mainly consists of two manifolds 3, multiple rows of microchannel flat tubes 7, and fins 8. Improvements have been made to the existing microchannel heat exchanger structure. The improved microchannel heat exchanger adds at least one adaptive sealing component 5 and several check valves 2 to prevent backflow at the outlet of the flat tubes 7 within each manifold 3. The manifold 3 is divided into a medium cavity 1 and an elastic cavity 4 by the adaptive sealing component 5. The check valves 2 are located within the medium cavity 1 to prevent the medium from flowing back into the elastic cavity 4 from one end of the flat tubes 7. The height of the elastic cavity 4 contracts due to the balance between the adaptive sealing component 5 and the medium pressure, thereby changing the volume of the medium cavity 1 and controlling the number of rows of flat tubes 7 connected to the medium cavity 1. Referring to the attached diagram, the specific working process is as follows: Scenario 1: Low load start-up (low refrigerant flow, low pressure) At this time, the refrigerant enters the upper medium cavity 1 of the left manifold 3 from the guide inlet. The pressure is small and the thrust generated is insufficient to overcome the pre-tightening force of the adaptive sealing component 5. Therefore, the adaptive sealing component 5 is in the extended state, the elastic cavity 4 is in the maximum state, and the other end of all the flat tubes 7 connected to the elastic cavity 4 is blocked by the check valve component 2.

[0029] The refrigerant can only flow through the top one or two rows of flat tubes 7 before flowing into the medium cavity 1 at the upper end of the right-side manifold 3. After flowing in the medium cavity 1, the medium flows back through the flat tubes 7 connected at both ends to the medium cavity 1 at the lower end of the left-side manifold 3. Finally, it flows into the medium cavity 1 at the lower end of the right-side manifold 3 through one or more flat tubes 7 at the bottom. The condensate is finally discharged from the outlet. During the entire circulation of the condensate, the combination of the adaptive sealing component 5 and the check valve component 2 ensures that no condensate enters the flat tubes 7 connected to the elastic cavity 4, thereby reducing the number of flat tubes 7 covered by condensate. At this time, it can ensure that the flow rate is high and the heat exchange efficiency is good under low load and low flow rate conditions, and can smoothly carry the lubricating oil back to the compressor.

[0030] Scenario 2: High-load operation (high refrigerant flow rate, high pressure) As the system load increases, the refrigerant flow rate increases, and the inlet pressure rises.

[0031] At this time, the pressure of the condensing medium pushes the adaptive sealing assembly 5 to contract, causing the elastic cavity 4 to shorten as the pressure increases. As the pressure increases, the medium cavity 1 becomes larger and larger, so that the area originally covered by the elastic cavity 4 at the inlet end is replaced by the medium cavity 1, allowing the medium to enter from the feed end of the flat tube 7. After passing through the flat tube 7, the medium is able to flow out from the check member 2 end and into the medium cavity 1 on the other side by pressure, thus realizing that the number of flat tubes 7 participating in heat exchange gradually increases with the pressure. When the system load is at its maximum, the adaptive sealing assembly 5 is in the maximum compression state, and all rows of flat tubes 7 are connected. In this state, all flat tubes 7 participate in heat exchange, and the heat exchange area reaches its maximum, meeting the peak load requirements.

[0032] This technology effectively solves the problems of traditional heat exchangers with a fixed 7 rows of flat tubes, resulting in poor heat exchange and difficulty in oil return at low loads due to slow flow rates; insufficient heat exchange at high loads due to insufficient number of rows; and the high cost and complex structure of existing electronic control solutions. It utilizes the medium's own pressure to drive an adaptive variable number of rows, eliminating the need for external energy sources and achieving a dynamic balance between "fewer rows of tubes at low loads (high flow rates) and more rows of tubes at high loads (larger heat exchange)," thus resolving the conflict between energy efficiency and oil return under all operating conditions.

[0033] A further improvement is made in that the adaptive sealing assembly 5 includes a fixed sealing partition 53, a piston plate 51, and an elastic reset member 52. The two ends of the elastic cavity 4 are sealed by the fixed sealing partition 53 and the piston plate 51. The elastic reset member 52 is disposed in the elastic cavity 4. The piston plate 51 moves under the balance of the elastic force of the elastic reset member 52 and the medium pressure to change the volume of the medium cavity 1, thereby controlling the number of rows of microchannel flat tubes 7 communicating with the medium cavity 1.

[0034] A fixed sealing partition 53 is horizontally fixed inside the manifold 3, thus forming an independent upper and lower partition structure within the internal cavity of the manifold 3. The piston plate 51 is mounted on the fixed sealing partition 53 via an elastic reset member 52. The piston plate 51 forms a sealed sliding relationship with the internal cavity of the manifold 3. Under pressure, it can slide up and down along the internal cavity of the manifold 3, preventing condensate from entering the elastic cavity 4 between the fixed sealing partition 53 and the piston plate 51 from the upper and lower media cavities 1. Simultaneously, it ensures that the piston plate 51 moves up and down under the balance of the elastic force of the elastic reset member 52 and the media pressure, thereby changing the volume of the media cavity 1 and controlling the number of rows of microchannel flat tubes 7 connected to the media cavity 1. Through the sandwich structure of "fixed sealing partition 53 + piston plate 51 + elastic reset member 52," the pressure signal is converted into a piston displacement signal by utilizing the interplay between elastic force and media pressure. The structure is simple and the principle is reliable, effectively solving the problem of how to physically partition the space within the manifold 3 and achieve force balance.

[0035] A further improvement is made in that the manifold 3 is provided with a vertical baffle 10, which divides the manifold 3 into a first chamber 11 that communicates with the guide port and a second chamber 12 that communicates with the inlet and outlet of the flat tube 7. The adaptive sealing component 5 is located in the first chamber 11. The second chamber 12 is provided with a plurality of horizontal baffles 9, which divide the second chamber 12 into a plurality of piston chambers 14 by the horizontal baffles 9. The vertical baffle 10 is provided with a through hole 13 that communicates with the piston chamber 14. One side of the piston chamber 14 is connected to the inlet and outlet of at least one of the flat tubes 7. The anti-reverse component 2 is provided on the through hole 13.

[0036] The manifold 3 is divided into a first chamber 11, which communicates with the guide port, and a second chamber 12, which communicates with the inlet and outlet of the flat tubes 7, by a vertical baffle 10. The adaptive sealing assembly 5 is installed in the first chamber 11. The thickness of the piston plate 51 is greater than the height of the through hole 13, which ensures that the piston plate 51 maintains a good sealing effect during its extension and retraction. The cooperation of the vertical baffle 10 and the horizontal baffle 9 creates an independent piston chamber 14. Combined with the design of the through hole 13, the movement of the piston plate 51 can precisely control the on / off state of each row of flat tubes 7 like a switch, preventing fluid short circuits and effectively solving the problem that existing structures cannot accurately control the on / off state of different numbers of rows of flat tubes 7 by the movement of the piston.

[0037] A further improvement is made so that when the travel range of the adaptive sealing component 5 is in the maximum compression state, the medium cavity 1 is connected to all the rows of flat tubes 7.

[0038] When the adaptive sealing component 5 is in the maximum compression state within the stroke range, it is located between two adjacent through holes 13, so that it will not block any of the through holes 13, allowing the medium cavity 1 to connect all the flat tubes 7, ensuring that the peak performance of the equipment is not compromised, and ensuring full power operation under maximum load.

[0039] A further improvement is made in that a sealing ring 6 is provided between the piston plate 51 and the vertical baffle 10; the elastic reset member 52 is a spring, and the stiffness and preload of the spring are set according to the flow rate and pressure of the system design conditions.

[0040] The piston plate 51 and the side wall of the medium cavity 1 are prone to gaps due to pressure. If the seal is not tight, refrigerant will leak into the unused flat tube 7 under low load, causing regulation failure. Introducing the "sealing ring 6" ensures airtightness between the piston plate 51 and the side wall of the medium cavity 1. This guarantees that under low load conditions, refrigerant will absolutely not flow through the cut-off flat tube 7, avoiding "dead zone" flow and oil return failure. The elastic reset component 52 uses a spring structure, and the spring's stiffness and preload are set according to the flow rate and pressure of the system design conditions. The spring parameters can be adjusted to adapt to the design conditions of different scenarios such as residential air conditioners and commercial heat pumps.

[0041] A further improvement is that the anti-reverse component 2 is located inside the medium cavity 1 to prevent the medium from flowing back from the manifold 3 to the microchannel flat tube 7.

[0042] The anti-reverse component 2 ensures that the medium can only flow from the piston chamber 14 to the medium chamber 1 in the manifold 3, preventing backflow from impacting the adaptive sealing component 5 and improving the system's operational stability and response speed under varying operating conditions.

[0043] A further improvement is that the check valve 2 adopts a one-way valve or a flap structure with a rotary connection.

[0044] The use of a mature mechanical structure results in low cost and durability, further reducing the manufacturing difficulty and cost of the heat exchanger.

[0045] The above embodiments are merely preferred embodiments of this application and should not be construed as limiting the scope of protection of this application. Any non-substantial changes and substitutions made by those skilled in the art based on this application shall fall within the scope of protection claimed by this application.

Claims

1. A microchannel heat exchanger with adaptive adjustment of the number of flat tube rows, comprising two manifolds (3) with flow guides, a plurality of flat tubes (7) disposed between the two manifolds (3), and fins (8), characterized in that: Both of the manifolds (3) are provided with a retractable adaptive sealing assembly (5) and several anti-reverse components (2) to prevent backflow at the outlet of the flat tube (7). The manifolds (3) are divided into a medium cavity (1) and an elastic cavity (4) by the adaptive sealing assembly (5). The anti-reverse components (2) are located in the medium cavity (1) to prevent the medium from flowing back from one end of the flat tube (7) into the elastic cavity (4). The height of the elastic cavity (4) is reduced by the balance between the adaptive sealing assembly (5) and the medium pressure to change the volume of the medium cavity (1) and thus control the number of rows of the flat tubes (7) connected to the medium cavity (1).

2. A microchannel heat exchanger with adaptive adjustment of the number of flat tube rows according to claim 1, characterized in that: The adaptive sealing assembly (5) includes a fixed sealing partition (53), a piston plate (51), and an elastic reset member (52). The two ends of the elastic cavity (4) are sealed by the fixed sealing partition (53) and the piston plate (51). The elastic reset member (52) is disposed in the elastic cavity (4). The piston plate (51) moves under the balance of the elastic force of the elastic reset member (52) and the medium pressure to change the volume of the medium cavity (1) and thereby control the number of rows of microchannel flat tubes (7) connected to the medium cavity (1).

3. A microchannel heat exchanger with adaptive adjustment of the number of flat tube rows according to claim 2, characterized in that: The manifold (3) is provided with a vertical baffle (10), which divides the manifold (3) into a first chamber (11) connected to the guide port and a second chamber (12) connected to the inlet and outlet of the flat tube (7). The adaptive sealing component (5) is located in the first chamber (11). The second chamber (12) is provided with several horizontal baffles (9). The second chamber (12) is divided into several piston chambers (14) by the horizontal baffles (9). The vertical baffle (10) is provided with a through hole (13) connected to the piston chamber (14). One side of the piston chamber (14) is connected to the inlet and outlet of at least one of the flat tubes (7). The anti-reverse component (2) is provided on the through hole (13).

4. A microchannel heat exchanger with adaptive adjustment of the number of flat tube rows according to claim 1, characterized in that: When the travel range of the adaptive sealing assembly (5) is in the maximum compression state, the medium cavity (1) is connected to all the rows of the flat tubes (7).

5. A microchannel heat exchanger with adaptive adjustment of the number of flat tube rows according to claim 3, characterized in that: A sealing ring (6) is provided between the piston plate (51) and the vertical baffle (10).

6. A microchannel heat exchanger with adaptive adjustment of the number of flat tube rows according to claim 2, characterized in that: The elastic reset component (52) is a spring, and the stiffness and preload of the spring are set according to the flow rate and pressure of the system design conditions.

7. A microchannel heat exchanger with adaptive adjustment of the number of flat tube rows according to claim 1, characterized in that: The anti-reverse component (2) is located inside the medium cavity (1) and is used to prevent the medium from flowing back from the manifold (3) to the microchannel flat tube (7).

8. A microchannel heat exchanger with adaptive adjustment of the number of flat tube rows according to claim 1, characterized in that: The anti-reverse component (2) adopts a one-way valve or a flap structure with a rotary connection.

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