Coaxial double pipe heat exchanger

Abstract

The utility model relates to heat exchanger technical field discloses a coaxial double pipe heat exchanger, include: the one end of first sleeve is provided with first entrance, the other end is provided with first export, is provided with the accommodating cavity in first sleeve, second sleeve is sleeved in the outside of first sleeve, forms first flow cavity between second sleeve and first sleeve, is provided with second entrance and second export on second sleeve, third sleeve is sleeved in the outside of second sleeve, forms second flow cavity between second sleeve and third sleeve, second flow cavity communicates with first flow cavity, and the refrigerant enters second flow cavity and flows out from third export, in the utility model, liquid takes away the heat in first flow cavity, when the refrigerant of first flow cavity enters second flow cavity, the refrigerant in second flow cavity further radiates heat and takes away the heat of first flow cavity, further carries out heat dissipation, its simple structure, and need not set up heat exchanger and expansion valve.

Description

Technical Field

[0001] This utility model relates to the field of heat exchanger technology, specifically to a coaxial sleeve heat exchanger. Background Technology

[0002] A heat pump system is a highly efficient heat exchange system based on the reverse Carnot cycle. It utilizes the phase change of refrigerant to "transfer" heat through four processes: compression, condensation, expansion, and evaporation. It generally consists of a compressor, a condenser, a throttling device, and an evaporator. The compressor compresses the refrigerant into a high-temperature, high-pressure superheated gas. After phase change in the condenser, the gas releases heat to the outside and becomes a high-temperature, high-pressure liquid. Then, after throttling, it becomes a gas-liquid two-phase mixture and enters the evaporator. In the evaporator, phase change occurs, and the gas absorbs heat from the outside and becomes a superheated gaseous refrigerant. Finally, the gas returns to the compressor for compression to form a cycle.

[0003] The economizer in a heat pump system is a key technology for improving system performance, especially in cold regions. Its core function can be summarized as enthalpy enhancement. By injecting superheated medium-pressure gaseous refrigerant into the intermediate chamber of the compressor, the system's heating capacity is increased, thereby enhancing the system's low-temperature operation capability. Therefore, in cold winter regions, heat pump air conditioners equipped with economizer enthalpy enhancement technology will achieve greater heating capacity and energy-saving effects. The core of this is the use of the economizer's enthalpy enhancement principle.

[0004] Shell-and-tube heat exchangers, used as condensers in heat pump air conditioners, are widely praised for their excellent antifreeze capabilities. Northern heating and air conditioning systems often rely on a combination of shell-and-tube heat exchangers and economizers. The economizer is typically also a heat exchanger, transferring heat between the main refrigerant and the auxiliary refrigerant. The main refrigerant becomes subcooled, while the auxiliary refrigerant becomes superheated, which then increases the compressor's enthalpy. However, this requires an additional heat exchanger and expansion valve on the auxiliary refrigerant line, increasing the system's complexity and cost. Utility Model Content

[0005] In view of this, the present invention provides a coaxial sleeve heat exchanger to solve the problem that the existing design requires a separate heat exchanger and expansion valve to be installed on the auxiliary circuit, which results in high cost.

[0006] In a first aspect, this utility model provides a coaxial sleeve heat exchanger, comprising: a first sleeve, one end of which is provided with a first inlet and the other end with a first outlet, and a receiving cavity is provided inside the first sleeve, wherein liquid enters from the first inlet of the first sleeve and flows out from the first outlet; The second sleeve is sleeved on the outside of the first sleeve, and a first flow cavity is formed between the second sleeve and the first sleeve. The second sleeve is provided with a second inlet and a second outlet. The refrigerant enters the first flow cavity through the second inlet and flows out from the second outlet. The third sleeve is fitted outside the second sleeve, and a second flow cavity is formed between the second sleeve and the third sleeve. The second flow cavity is connected to the first flow cavity. The third sleeve is provided with a third outlet, and the refrigerant enters the second flow cavity and flows out from the third outlet.

[0007] Beneficial effects: Through the second and third sleeves installed outside the first sleeve, liquid flows in the receiving cavity of the first sleeve, and refrigerant is placed in the first and second flow cavities. The liquid in the receiving cavity carries away the heat of the refrigerant in the first flow cavity. When the refrigerant in the first flow cavity enters the second flow cavity, the temperature of the refrigerant in the second flow cavity decreases, further absorbing heat, increasing the superheat of the refrigerant in the first flow cavity, and decreasing the temperature of the refrigerant in the first flow cavity.

[0008] In one alternative embodiment, the second sleeve is provided with at least one through hole at the end facing away from the second inlet, the through hole connecting the first flow chamber and the second flow chamber, and the refrigerant enters the second flow chamber through the through hole.

[0009] Beneficial effects: By setting the through hole at the end of the second sleeve away from the second inlet, when the refrigerant enters the second sleeve from the second inlet and flows toward the second outlet, after heat exchange, most of the refrigerant flows out from the second outlet, and a small portion of the refrigerant enters the second flow chamber through the through hole, and exchanges heat with the refrigerant in the first flow chamber again. At this time, the refrigerant in the second flow chamber is in a gas-liquid two-phase state, which increases the heat exchange effect.

[0010] In one alternative embodiment, a buffer section with a diameter larger than that of the second sleeve is provided at one end of the second sleeve near the first inlet, and the through hole is provided on the buffer section.

[0011] Beneficial effects: When the refrigerant passes through the through hole on the buffer section, the flow velocity increases and the pressure is converted into kinetic energy, resulting in pressure loss. When it flows into the second flow chamber, it suddenly decelerates and loses kinetic energy, thus achieving the effect of pressure reduction and throttling. At this time, the refrigerant changes from a liquid state to a gas-liquid two-phase state.

[0012] In one optional embodiment, the third sleeve has a connecting section with a diameter larger than that of the third sleeve, and a third flow cavity is formed between the connecting section and the buffer section, and the through hole communicates with the third flow cavity.

[0013] Beneficial effect: During installation, the connecting section is fitted onto the buffer section of the second sleeve, thereby fixing the connecting section and the buffer section together and facilitating its processing.

[0014] In one alternative embodiment, the second outlet is disposed on the buffer section and extends radially outward.

[0015] Beneficial effect: By setting the second outlet on the buffer section and extending it radially outward, it is convenient to process and fix the second outlet and the buffer section.

[0016] In one alternative embodiment, the through holes are provided at multiple intervals along the circumference of the second sleeve.

[0017] Beneficial effects: By setting multiple through holes at intervals along the circumference of the second sleeve, the refrigerant can flow into the second flow chamber more evenly, resulting in more uniform refrigerant distribution, thereby improving the heat exchange effect and allowing the heat of the liquid in the first sleeve to be carried away more quickly.

[0018] In one alternative embodiment, the length of the second sleeve is greater than the length of the third sleeve.

[0019] Beneficial effects: By making the length of the second sleeve longer than that of the third sleeve, the material used in the third sleeve can be reduced while ensuring effective heat exchange, thus lowering costs. The shorter length of the third sleeve also facilitates installation and maintenance. At the same time, this structure does not affect the full heat exchange of the refrigerant in the second flow cavity to the second sleeve, and can still ensure the good heat exchange performance of the overall heat exchanger.

[0020] In one alternative implementation, the length of the first sleeve is greater than the length of the second sleeve.

[0021] Beneficial effects: By making the length of the first sleeve greater than that of the second sleeve, on the one hand, the flow path of the liquid in the cavity inside the first sleeve can be increased, allowing the liquid to have more sufficient flow time in the first sleeve, thereby achieving more complete heat exchange with the refrigerant in the first flow cavity; on the other hand, it can optimize the internal spatial layout of the heat exchanger, improve space utilization, and ensure that an effective flow cavity is formed between the first, second, and third sleeves to achieve good heat exchange function, and to a certain extent, it can reduce material costs.

[0022] In one optional embodiment, a spiral portion is provided on the outer wall of the first sleeve, the spiral portion extends spirally along the extension direction of the first sleeve, and a spiral cavity is provided inside the spiral portion, the spiral cavity communicating with the receiving cavity.

[0023] Beneficial effects: When the liquid flows in the containment cavity and the spiral cavity, the spiral cavity guides the liquid flow and forms a spiral stirring of the liquid, causing the liquid in the center of the first tube to be continuously thrown towards the tube wall, while at the same time the liquid on the tube wall is rolled towards the center to form a vortex. This allows the liquid in the center of the tube to mix with the superheated liquid near the tube wall, reducing the thermal boundary layer. The thinning and disturbance significantly reduce the thermal resistance and improve the efficiency of heat transfer.

[0024] In one alternative embodiment, the outer wall of the spiral portion of the first sleeve abuts against the inner wall of the second sleeve, and a first flow cavity is formed between the second sleeve and the spiral portion.

[0025] Beneficial effects: The refrigerant flows in the first flow cavity. Since the outer wall of the first sleeve abuts against the inner wall of the second sleeve, the first flow cavity forms a spirally extending cavity. During the flow process, the refrigerant will flow along the spiral path, which can increase the flow path and flow time of the refrigerant in the first flow cavity, making the contact between the refrigerant and the outer wall of the first sleeve more sufficient, thereby enhancing the heat exchange effect between the refrigerant and the liquid in the first sleeve, and effectively improving the overall heat exchange efficiency of the heat exchanger. Attached Figure Description

[0026] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0027] Figure 1 This is a perspective view of a coaxial sleeve heat exchanger according to an embodiment of the present utility model; Figure 2 for Figure 1 A 3D view of the hidden buffer section and connecting section of the coaxial sleeve heat exchanger shown. Figure 3 for Figure 1 Longitudinal sectional view of the buffer section and connecting section; Figure 4 for Figure 1 A 3D view of the buffer section in the middle; Figure 5 for Figure 1 A cross-sectional view of the first, second, and third sleeves along their length. Figure 6 for Figure 1 A cross-sectional view of the first, second, and third sleeves from another perspective.

[0028] Explanation of reference numerals in the attached figures: 1. First sleeve; 2. Second sleeve; 3. Third sleeve; 4. First inlet; 5. First outlet; 6. First flow chamber; 7. Second inlet; 8. Second outlet; 9. Second flow chamber; 10. Through hole; 11. Buffer section; 12. Connecting section; 13. Third outlet. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0030] The following is combined Figures 1 to 6 The following describes embodiments of the present invention.

[0031] like Figure 1 , Figure 2 , Figure 3 As shown in the figure, according to an embodiment of the present invention, a coaxial sleeve heat exchanger is provided, comprising: a first sleeve 1, a second sleeve 2, and a third sleeve 3. The second sleeve 2 is sleeved outside the first sleeve 1, and the third sleeve 3 is sleeved outside the second sleeve 2. The first sleeve 1 has a first inlet 4 at one end along its length and a first outlet 5 at the other end. A receiving cavity is provided inside the first sleeve 1, through which liquid enters the receiving cavity from the first inlet 4 and flows out from the first outlet 5. A first flow cavity 6 is formed between the second sleeve 2 and the first sleeve 1. The second sleeve 2 has a second inlet 7 and a second outlet 8. Refrigerant enters the first flow cavity 6 through the second inlet 7 and flows out from the second outlet 8. The third sleeve 3 is sleeved outside the second sleeve 2, forming a second flow cavity 9 between the second sleeve 2 and the third sleeve 3. The second flow cavity 9 communicates with the first flow cavity 6. The refrigerant in the first flow cavity 6 enters the second flow cavity 9 and then flows out from the third outlet 13 on the third sleeve 3.

[0032] In use, the liquid flowing in the first sleeve 1 is the refrigerant, and the first flow chamber 6 and the second flow chamber 9 contain refrigerant. The second inlet 7 is located on the side away from the first inlet 4. That is, after the refrigerant enters through the second inlet 7, it flows towards the second outlet 8, while the refrigerant in the first inlet 4 flows towards the first outlet 5. The flow direction of the refrigerant is opposite to that of the refrigerant, thereby maximizing the heat exchange efficiency.

[0033] Through the second sleeve 2 and the third sleeve 3 fitted outside the first sleeve 1, liquid flows in the receiving cavity of the first sleeve 1, and refrigerant flows in the first flow cavity 6 and the second flow cavity 9. The liquid in the receiving cavity carries away the heat of the refrigerant in the first flow cavity 6. When the refrigerant in the first flow cavity 6 enters the second flow cavity 9, the temperature of the refrigerant in the second flow cavity 9 decreases, further absorbing heat, increasing the superheat of the refrigerant in the first flow cavity 6, and decreasing the temperature of the refrigerant in the first flow cavity 6.

[0034] Specifically, both the second sleeve 1 and the third sleeve 3 are circular tubes.

[0035] like Figure 4 As shown, in this embodiment, at least one through hole 10 is provided on the second sleeve 2 at the end away from the second inlet 7. The through hole 10 penetrates the second sleeve 2 radially, thereby connecting the first flow chamber 6 and the second flow chamber 9. The refrigerant enters the second flow chamber 9 through the through hole 10. Specifically, the through hole 10 is a circular hole. By setting the through hole 10 at the end of the second sleeve 2 away from the second inlet 7, that is, near the second outlet 8, when the refrigerant enters the second sleeve 2 from the second inlet 7 and flows towards the second outlet 8, after heat exchange, a portion of the refrigerant enters the second flow chamber 9 after being throttled through the through hole 10, becoming auxiliary circulation refrigerant that exchanges heat with the refrigerant in the first flow chamber 6, thus achieving the effect of an economizer. It should be noted that, as an alternative implementation, the through hole 10 can also be set to one. In this case, the through hole 10 can be set such that its diameter gradually decreases as it extends radially outward from the center, causing the liquid pressure and temperature to decrease after passing through the through hole 10.

[0036] like Figure 3 , Figure 4 As shown, in this embodiment, a buffer section 11 with a diameter larger than that of the second sleeve 2 is provided at one end near the first inlet 4, and a through hole 10 is provided on the buffer section 11. The buffer section 11 is a circular tube. The buffer section 11 is integrally formed with the second sleeve 2. By providing a buffer section 11 with a diameter larger than that of the second sleeve 2 on the second sleeve 2, the pressure decreases and the temperature drops when the liquid passes through the through hole 10. It should be noted that, as an alternative implementation, the buffer section 11 may not be provided, and the through hole 10 may be directly provided on the second sleeve 2.

[0037] Specifically, the buffer section 11 is a circular tube, with its two ends nested on the first sleeve 1 and the second sleeve 2, respectively. The two ends of the buffer section 11 are then brazed to seal the gaps between the buffer section 11 and the first sleeve 1 and the second sleeve 2. Alternatively, if the buffer section 11 is not used, the diameter of the end of the second sleeve 2 can be gradually reduced until it matches the outer diameter of the first sleeve 1, and then the second sleeve 2 can be welded to the first sleeve 1.

[0038] like Figure 3As shown, in this embodiment, the third sleeve 3 has a connecting section 12 with a diameter larger than that of the third sleeve 3. A third flow cavity is formed between the connecting section 12 and the buffer section 11, and the third flow cavity is communicated through the hole 10. The refrigerant enters the connecting section 12 through the hole 10, and then enters the third sleeve 3, which has a diameter smaller than that of the connecting section 12. It should be noted that, as an alternative implementation, the third sleeve 3 may not have a connecting section 12, but instead the diameter of the end of the third sleeve 3 may be gradually reduced until the diameter of the end of the third sleeve 3 is the same as the outer diameter of the second sleeve 2, thereby directly brazing and fixing the third sleeve 3 and the second sleeve 2.

[0039] Specifically, the connecting section 12 is a round tube, and its two ends are nested on the second sleeve 2 and the third sleeve 3 respectively. The two ends of the connecting section 12 are welded together by brazing.

[0040] like Figure 3 As shown, in this embodiment, the second outlet 8 is provided on the buffer section 11 and extends radially outward. After the refrigerant flows in, it flows outward along the radial direction through the second outlet 8, with a portion of the refrigerant entering the second flow cavity 9 through the through hole 10. This is achieved by providing the second outlet 8 on the buffer section 11 and extending radially outward.

[0041] like Figure 4 As shown, in this embodiment, multiple through holes 10 are spaced apart along the circumference of the second sleeve 2. Specifically, the diameter of the through holes 10 is 0.7 mm. When the refrigerant passes through the smaller diameter through holes 10, the flow rate increases. After entering the second flow chamber 9, the refrigerant velocity decreases, kinetic energy is lost, and the pressure drop is large, resulting in a decrease in pressure. The through holes 10 act as an expansion valve in the refrigeration system. Due to the decrease in pressure, the saturation temperature of the refrigerant decreases. When the temperature of the refrigerant exceeds the saturation temperature, a portion of the liquid refrigerant boils instantaneously, changing from a liquid to a gaseous state. After absorbing heat through vaporization, it becomes a gas-liquid two-phase mixture. At this time, the refrigerant entering the second flow chamber 9 is a low-temperature, low-pressure gas-liquid mixture. By arranging multiple through holes 10 spaced apart along the circumference of the second sleeve 2, the refrigerant can flow more evenly into the second flow chamber 9, thereby improving the heat exchange effect. It should be noted that, as an alternative implementation, the diameter of the through holes 10 can also be set to 0.5-1.5 mm, which can be adjusted by those skilled in the art according to actual needs.

[0042] like Figure 2As shown, in this embodiment, the length of the second sleeve 2 is greater than the length of the third sleeve 3, and the length of the first sleeve 1 is greater than the length of the second sleeve 2. Specifically, the length of the second sleeve 2 is 100mm shorter than the length of the first sleeve 1, and the length of the third sleeve 3 is 100mm shorter than the length of the second sleeve 2. During installation, the second sleeve 2 is fitted onto the outside of the first sleeve 1, with both ends of the second sleeve 2 50mm away from both ends of the first sleeve 1. A buffer section 11 is fitted onto the first sleeve 1 and the second sleeve 2, and the buffer section 11 is brazed to the first sleeve 1 and the second sleeve 2 for fixation. Then, the third sleeve 3 is fitted onto the second sleeve 2, with both ends of the third sleeve 3 50mm away from both ends of the second sleeve 2. A connecting section 12 is fitted onto the second sleeve 2, and the connecting section 12 is brazed to both the second sleeve 2 and the third sleeve 3 for fixation. By making the length of the second sleeve 2 greater than the length of the third sleeve 3, effective heat exchange can be ensured while reducing the material usage of the third sleeve 3, thus reducing costs. The length of the first sleeve 1 is greater than the length of the second sleeve 2, which increases the flow path of the liquid in the cavity within the first sleeve 1, allowing the liquid more sufficient flow time within the first sleeve 1, thus enabling more thorough heat exchange with the refrigerant in the first flow cavity 6. Simultaneously, it optimizes the internal spatial layout of the heat exchanger, improving space utilization, while ensuring an effective flow cavity is formed between the first sleeve 1, the second sleeve 2, and the third sleeve 3 to achieve good heat exchange function, and to some extent, reducing material costs. It should be noted that, as an alternative implementation, the actual lengths of the first sleeve 1, the second sleeve 2, and the third sleeve 3 can be adjusted according to actual needs; this embodiment does not impose any limitations on them. Furthermore, the first sleeve 1 can also be 50-100mm longer than the second sleeve 2, and the third sleeve 3 can also be 50-100mm longer than the second sleeve 2.

[0043] like Figure 5 , Figure 6 As shown, in this embodiment, a spiral portion is provided on the outer wall of the first sleeve 1. The spiral portion extends spirally along the extension direction of the first sleeve 1, and a spiral cavity is provided inside the spiral portion, which communicates with the receiving cavity. When the liquid flows in the receiving cavity and the spiral cavity, the spiral cavity guides the liquid flow, forming a spiral stirring of the liquid. This causes the liquid at the center of the first sleeve 1 to be continuously thrown towards the pipe wall, while simultaneously drawing the liquid on the pipe wall towards the center, forming a vortex. This allows the liquid at the center of the pipe to mix with the superheated liquid near the pipe wall, reducing the thermal boundary layer. The thinning and disturbance significantly reduce the thermal resistance and improve the efficiency of heat transfer. Specifically, both ends of the first sleeve 1 are still set as circular tubes to facilitate welding and fixing with the second sleeve 2. The threaded portion is located in the middle part of the first sleeve 1. It should be noted that, as an alternative implementation, the spiral portion can be omitted, and the third sleeve 3 can be directly set as a circular tube.

[0044] like Figure 5 As shown, in this embodiment, the outer wall of the spiral portion of the first sleeve 1 abuts against the inner wall of the second sleeve 2, forming a first flow cavity 6 between the second sleeve 2 and the spiral portion. The first flow cavity 6 is also spirally extended. Specifically, the refrigerant flows within the first flow cavity 6. Because the outer wall of the first sleeve 1 abuts against the inner wall of the second sleeve 2, the first flow cavity 6 forms a spirally extended cavity. During flow, the refrigerant flows along a spiral path, increasing the flow path and time within the first flow cavity 6. This allows for more thorough contact between the refrigerant and the outer wall of the first sleeve 1, thereby enhancing the heat exchange effect between the refrigerant and the liquid within the first sleeve 1 and effectively improving the overall heat exchange efficiency of the heat exchanger. It should be noted that, as an alternative implementation, the spiral portion of the first sleeve 1 may not abut against the second sleeve 2.

[0045] Specifically, the refrigerant flows within the spirally extending first flow cavity 6. Due to the spiral arrangement of the first flow cavity 6, the refrigerant flows in a spiral pattern, increasing its velocity and effectively thinning the heat transfer boundary layer. Within the first flow cavity 6, the refrigerant changes from a superheated gaseous state to a two-phase gas-liquid mixture and then to a subcooled liquid state. During the heat exchange process, when it condenses into a liquid state, liquid refrigerant forms on the inner wall of the spiral first flow cavity 6. Due to its spiral flow, the liquid refrigerant is thrown away from the heat transfer surface under the action of centrifugal force, ensuring that the gaseous refrigerant remains in contact with the pipe wall, thus continuing to condense.

[0046] Installation method of coaxial sleeve heat exchanger: During installation, the second sleeve 2 is fitted over the outside of the first sleeve 1, with both ends of the second sleeve 2 50mm away from both ends of the first sleeve 1. Buffer sections 11 are fitted over the first sleeve 1 and the second sleeve 2, and then brazed to fix them in place. Next, the third sleeve 3 is fitted over the second sleeve 2, with both ends of the third sleeve 3 50mm away from both ends of the second sleeve 2. Connecting sections 12 are fitted over the second sleeve 2, and then brazed to fix them in place to both the second sleeve 2 and the third sleeve 3. Two buffer sections 11 are fixed at both ends of the second sleeve 2. The buffer section 11 near the first inlet 4 has a second outlet 8, and the buffer section 11 near the first outlet 5 has a first inlet 4. Two connecting sections 12 are provided at both ends of the third sleeve 3, with the connecting section 12 near the second inlet 7 having a third outlet 13. After installation, the first sleeve 1, the second sleeve 2, and the third sleeve 3 are coaxially arranged. The first sleeve 1 has an outer diameter of 25mm, a wall thickness of 2mm, and an outer diameter of 27mm for the threaded portion. The second sleeve 2 has an inner diameter of 27mm and an outer diameter of 30mm. The third sleeve 3 has an outer diameter of 35mm. The buffer section 11 has an inner diameter of 30mm at one end and a wall thickness of 2mm at the other end, and an inner diameter of 25mm at the other end. The connecting section 12 has an inner diameter of 35mm at one end and a wall thickness of 2mm at the other end, and an inner diameter of 32mm at the other end.

[0047] The working principle of this coaxial sleeve heat exchanger is as follows: When the system is running, the main circulating refrigerant operates as follows: The high-temperature and high-pressure gaseous refrigerant (i.e., the refrigerant) from the compressor enters the first flow chamber 6 through the second inlet 7, and the coolant (i.e., the liquid mentioned above) enters the first sleeve 1 through the first inlet 4. The refrigerant and the coolant flow in opposite directions, thereby achieving counter-current heat exchange. The refrigerant condenses from the gaseous state to the liquid state and flows out from the second outlet 8. It enters the expansion valve in the system for throttling. After throttling, it becomes a gas-liquid mixture and enters the evaporator to evaporate into a superheated gaseous state. It then returns to the compressor and is compressed again into a high-temperature and high-pressure gaseous refrigerant, which enters from the second inlet 7. The auxiliary cycle refrigerant operates as follows: it is injected from the intermediate-pressure chamber of the enthalpy-increasing compressor and merges with the main cycle refrigerant. After compression, it becomes a high-temperature, high-pressure gaseous refrigerant, which enters the first flow chamber 6 through the second inlet 7. Upon reaching the outlet of the first flow chamber 6, it is throttled through the through-hole 10 and enters the second flow chamber 9. After throttling, the refrigerant changes from a high-pressure, high-temperature liquid to a low-temperature, low-pressure gas-liquid two-phase state, becoming the auxiliary cycle refrigerant. At this point, the refrigerant in the second flow chamber 9 exchanges heat counter-currently with the refrigerant in the first flow chamber 6. Heated by the high-temperature main cycle refrigerant, it becomes a superheated gaseous refrigerant and is discharged from the third outlet 13. After discharge, it enters the intermediate-pressure chamber of the compressor and continues to merge with the main cycle refrigerant. Through mutual heat exchange between the main and auxiliary cycle refrigerants, the auxiliary cycle provides more subcooling to the main cycle, improving the evaporator heat exchange capacity of the main cycle system. The main cycle provides superheated gaseous refrigerant to the auxiliary cycle, which is injected into the compressor for enthalpy increase, improving the system's heating capacity during winter operation.

[0048] Although embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A coaxial sleeve heat exchanger, characterized in that, include: The first sleeve (1) has a first inlet (4) at one end and a first outlet (5) at the other end. The first sleeve (1) has a receiving cavity inside. Liquid enters from the first inlet (4) of the first sleeve (1) and flows out from the first outlet (5). The second sleeve (2) is sleeved on the outside of the first sleeve (1). The second sleeve (2) and the first sleeve (1) form a first flow cavity (6). The second sleeve (2) is provided with a second inlet (7) and a second outlet (8). The refrigerant enters the first flow cavity (6) through the second inlet (7) and flows out from the second outlet (8). The third sleeve (3) is sleeved on the outside of the second sleeve (2). The second sleeve (2) and the third sleeve (3) form a second flow cavity (9). The second flow cavity (9) is connected to the first flow cavity (6). The third sleeve (3) is provided with a third outlet (13). The refrigerant enters the second flow cavity (9) and flows out from the third outlet (13).

2. The coaxial sleeve heat exchanger according to claim 1, characterized in that, The second sleeve (2) is provided with at least one through hole (10) at the end away from the second inlet (7). The through hole (10) connects the first flow chamber (6) and the second flow chamber (9). The refrigerant enters the second flow chamber (9) through the through hole (10).

3. The coaxial sleeve heat exchanger according to claim 2, characterized in that, The second sleeve (2) is provided with a buffer section (11) with a diameter larger than that of the second sleeve (2) at one end near the first inlet (4), and the through hole (10) is provided on the buffer section (11).

4. The coaxial sleeve heat exchanger according to claim 3, characterized in that, The third sleeve (3) has a connecting section (12) with a diameter larger than that of the third sleeve (3), and a third flow cavity is formed between the connecting section (12) and the buffer section (11), and the through hole (10) is connected to the third flow cavity.

5. The coaxial sleeve heat exchanger according to claim 4, characterized in that, The second outlet (8) is provided on the buffer section (11) and extends radially outward.

6. The coaxial sleeve heat exchanger according to claim 2, characterized in that, Multiple through holes (10) are provided at circumferential intervals along the second sleeve (2).

7. The coaxial sleeve heat exchanger according to any one of claims 1-6, characterized in that, The length of the second sleeve (2) is greater than the length of the third sleeve (3).

8. The coaxial sleeve heat exchanger according to claim 7, characterized in that, The length of the first sleeve (1) is greater than the length of the second sleeve (2).

9. The coaxial sleeve heat exchanger according to any one of claims 1-6, characterized in that, The outer wall of the first sleeve (1) is provided with a spiral part, which extends spirally along the extension direction of the first sleeve (1). A spiral cavity is provided inside the spiral part, and the spiral cavity is connected to the receiving cavity.

10. The coaxial sleeve heat exchanger according to claim 9, characterized in that, The outer wall of the spiral part of the first sleeve (1) abuts against the inner wall of the second sleeve (2), and a second flow cavity (9) is formed between the second sleeve (2) and the spiral part.

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