Coaxial heat exchanger, evaporator, condenser and refrigeration system

Abstract

The present invention discloses a coaxial heat exchanger, an evaporator, a condenser, and a refrigeration system. The coaxial heat exchanger includes at least one connecting pipe, at least one secondary refrigerant pipe, and multiple refrigerant pipes. The secondary refrigerant pipe and the refrigerant pipe are coaxially arranged, and the refrigerant pipes are respectively provided on the inner and outer sides of the secondary refrigerant pipe. The refrigerant pipes are connected by the connecting pipe. Refrigerant enters from one refrigerant pipe and continuously exchanges heat with the secondary refrigerant in the secondary refrigerant pipe, thereby achieving a mixed flow process rather than the single flow process used in the prior art. The enhanced effect of the mixed flow process of the coaxial heat exchanger increases the flow velocity variation of the refrigerant within the heat exchanger, increases the turbulence, and increases the heat transfer coefficient and heat transfer capacity of the overall heat exchanger.

Description

Technical Field

[0001] The present invention relates to the technical field of heat exchange of refrigeration systems, and in particular to a coaxial heat exchanger, an evaporator, a condenser and a refrigeration system. Background Art

[0002] The coaxial heat exchanger consists of an inner tube and an outer tube. The cold and hot fluids flow in the inner tube and in the annular gap between the inner tube and the outer tube respectively to transfer heat. The coaxial heat exchanger has the advantages of pressure resistance and shock resistance, not easy to deform, not easy to clog, and smooth oil return.

[0003] In the prior art, the coaxial heat exchanger used as an evaporator has a single refrigerant flow path. During the heat exchange process, the refrigerant side channel area remains the same, but the refrigerant has a high density, low flow rate, and low heat transfer coefficient in the first half. In the second half, the density is low, the flow rate is high, and the pressure drop is large, and the flow does not change with changes in the refrigerant. As a condenser, the refrigerant also has a single flow path. During the heat exchange process, the refrigerant side channel area remains the same, but the refrigerant has a low density, high flow rate, and high pressure drop in the first half. In the second half, the density is high, the flow rate is low, and the heat transfer coefficient is low, and the flow does not change with changes in the refrigerant. In other words, the prior art coaxial heat exchanger is not adapted to the characteristics of the refrigerant in different states, and fails to fully exert the heat transfer effect of the heat exchanger. Summary of the Invention

[0004] Therefore, the technical problem to be solved by the present invention is to overcome the defect that the coaxial heat exchanger in the prior art is not adapted to the characteristics of the refrigerant in different states and fails to fully exert the heat transfer effect of the heat exchanger, thereby providing a coaxial heat exchanger, evaporator, condenser and refrigeration system.

[0005] A coaxial heat exchanger includes at least one connecting pipeline, at least one coolant pipeline and multiple refrigerant pipelines. The coolant pipeline and the refrigerant pipeline are coaxially arranged, and the refrigerant pipelines are respectively provided on the inner side and the outer side of the coolant pipeline. The refrigerant pipelines are connected by the connecting pipeline.

[0006] Furthermore, each of the refrigerant pipelines is provided with at least two refrigerant openings, and the connecting pipeline connects the refrigerant openings located on different refrigerant pipelines; each of the secondary coolant pipelines is provided with at least two secondary coolant openings.

[0007] Furthermore, in the refrigerant pipeline and the brine pipeline, the pipeline portion located on the inner side is exposed from the adjacent pipeline located on the outer side.

[0008] Furthermore, in the refrigerant pipeline and the brine pipeline, the end of the pipeline located on the inner side is exposed from the end of the adjacent pipeline located on the outer side.

[0009] Furthermore, the refrigerant opening is provided at the exposed portion of the refrigerant pipeline, and / or the brine opening is provided at the exposed portion of the brine pipeline.

[0010] Furthermore, the number of the refrigerant pipelines is one more than the number of the secondary coolant pipelines.

[0011] Furthermore, two refrigerant pipelines are provided, and one secondary coolant pipeline is provided.

[0012] An evaporator comprises the above-mentioned coaxial heat exchanger.

[0013] A condenser comprises the above-mentioned coaxial heat exchanger.

[0014] A refrigeration system comprises the above-mentioned evaporator and / or the above-mentioned condenser.

[0015] The technical solution of the present invention has the following advantages:

[0016] 1. The present invention provides a coaxial heat exchanger, comprising at least one connecting pipeline, at least one secondary refrigerant pipeline and a plurality of refrigerant pipelines, wherein the secondary refrigerant pipeline and the refrigerant pipeline are coaxially arranged, and the refrigerant pipeline is respectively provided on the inner side and the outer side of the secondary refrigerant pipeline, and the refrigerant pipelines are connected by the connecting pipeline. In a coaxial heat exchanger of this structure, the refrigerant enters from one refrigerant pipeline to another refrigerant pipeline and always exchanges heat with the secondary refrigerant in the secondary refrigerant pipeline, thereby realizing a mixed process instead of a single process in the prior art. Through the strengthening effect of the mixed process of the coaxial heat exchanger, the flow velocity change of the refrigerant in the heat exchanger is increased, the turbulence is increased, and the heat transfer coefficient and heat transfer amount of the overall heat exchanger are increased. When used as an evaporator, the mixed process is used, and the difference between the saturation temperature of the refrigerant in the heat exchanger and the secondary refrigerant temperature is large. It effectively ensures superheat, thereby improving the heat transfer performance of convection heat transfer and heat exchanger. The convection heat transfer process is divided into phase change zone and superheat zone. The heat transfer coefficient of phase change zone is large, and the heat transfer coefficient of superheat zone is low. Through the mixed process, that is, the refrigerant exchanges heat with the refrigerant multiple times, it can be effectively guaranteed that: when the refrigerant is in gas-liquid two-phase, the density is large, the required channel is small, the flow rate is increased, and the heat transfer is improved. When the refrigerant is in gas phase, the density is small, and a larger channel is required to reduce the pressure drop, increase the outlet saturation temperature, and due to the large temperature difference of the counterflow , it is easier to produce superheat, so that the heat exchange area required under the same heat exchange conditions is smaller, and the volume of the heat exchanger is also reduced. While maintaining the same volume as the single-pass heat exchanger, the heat exchange area of ​​the phase change zone is effectively increased, so that the heat transfer coefficient is highly efficient throughout the process, and thus it can adapt to higher heat exchange requirements; when used as a condenser, the mixed process effectively improves the refrigerant's shortcomings of low density, high flow rate, and high pressure drop in the first half, and high density, low flow rate, and low heat transfer coefficient in the second half, thereby improving convective heat transfer and heat exchange efficiency. Thermal performance, and the convective heat transfer process is divided into a phase change zone and a supercooling zone. The heat transfer coefficient in the phase change zone is large, and the heat transfer coefficient in the supercooling zone is low. Through the mixed process, that is, the refrigerant exchanges heat with the refrigerant multiple times, it can be effectively guaranteed that: when the refrigerant is in the gas phase, the density is small, and a larger channel is required to reduce the pressure drop and improve the heat exchange. When the refrigerant is in the gas-liquid two-phase, the density is large, and the required channel is small, which increases the flow rate and improves the heat exchange. Due to the two convective heat exchanges, the supercooling degree is effectively guaranteed, thereby improving the convective heat exchange and the heat exchange performance of the heat exchanger.

[0017] 2. The present invention provides a coaxial heat exchanger in which the inner portion of the refrigerant and brine pipelines is partially exposed to the outer portion of the adjacent pipeline. This coaxial heat exchanger facilitates the installation of refrigerant and brine openings.

[0018] 3. In the coaxial heat exchanger provided by the present invention, the number of the refrigerant pipeline is one more than the number of the brine pipeline. A coaxial heat exchanger with this structure fully utilizes the refrigerant pipeline and the brine pipeline.

[0019] 4. The present invention provides an evaporator comprising the above-mentioned coaxial heat exchanger. The evaporator of this structure, since it comprises the above-mentioned coaxial heat exchanger, naturally has the advantages brought by the inclusion of the above-mentioned coaxial heat exchanger.

[0020] 5. The present invention provides a condenser comprising the above-mentioned coaxial heat exchanger. A condenser of this structure, since it comprises the above-mentioned coaxial heat exchanger, naturally has the advantages brought by the inclusion of the above-mentioned coaxial heat exchanger.

[0021] 6. The present invention provides a refrigeration system comprising the aforementioned evaporator and / or condenser. This structured refrigeration system, by virtue of including the aforementioned evaporator and / or condenser, naturally offers the advantages inherent in such inclusion. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0023] Figure 1 This is a schematic structural diagram of the coaxial heat exchanger provided in Example 1 of the present invention;

[0024] Figure 2 for Figure 1 A cross-sectional view of a coaxial heat exchanger is shown;

[0025] Figure 3 for Figure 1 A cross-sectional view of the coaxial heat exchanger from another perspective is shown;

[0026] Figure 4 for Figure 1 A schematic diagram comparing a mixed process when a coaxial heat exchanger is used as an evaporator and a single process in the prior art is shown;

[0027] Figure 5 for Figure 1 A schematic diagram comparing a mixed flow when a coaxial heat exchanger is used as a condenser and a single flow in the prior art is shown;

[0028] Figure 6 for Figure 1 A schematic structural diagram of another embodiment of a coaxial heat exchanger is shown;

[0029] Description of reference numerals:

[0030] 1-first refrigerant pipeline, 2-second refrigerant pipeline, 3-second refrigerant pipeline, 4-first refrigerant opening, 5-second refrigerant opening, 6-first refrigerant opening, 7-second refrigerant opening, 8-third refrigerant opening, 9-fourth refrigerant opening, 10-connecting pipeline, 11-refrigerant inlet, 12-refrigerant outlet, 13-single flow, 14-mixed flow, 15-connecting sleeve. DETAILED DESCRIPTION

[0031] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0032] In the description of the present invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely to facilitate and simplify the description of the present invention. They are not intended to indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation, and therefore should not be construed as limitations on the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0033] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0034] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0035] Example 1

[0036] This embodiment provides a coaxial heat exchanger, comprising at least one connecting pipe 10, at least one secondary refrigerant pipe 2 and a plurality of refrigerant pipes, wherein the secondary refrigerant pipe 2 and the refrigerant pipe are coaxially arranged, and refrigerant pipes are respectively arranged on the inner side and the outer side of the secondary refrigerant pipe 2, and the refrigerant pipes are connected by the connecting pipe 10. The connecting pipe 10, the secondary refrigerant pipe 2 and the refrigerant pipe can be copper pipes, stainless steel pipes, nickel-white copper pipes, steel pipes, titanium pipes or pipes of other materials; and the pipes of the coaxial heat exchanger as a whole can be as follows Figure 1 The structure shown is a U-shaped structure, a square structure, a circular structure, a mosquito coil structure, a double-circle structure, or a structure of other shapes.

[0037] like Figure 1 As shown, in this embodiment, there are two refrigerant pipelines and one secondary coolant pipeline 2. Figure 1 and Figure 3 In the embodiment, the refrigerant pipeline located inside the secondary refrigerant pipeline 2 is called the first refrigerant pipeline 1, and the refrigerant pipeline located outside the secondary refrigerant pipeline 2 is called the second refrigerant pipeline 3. The outer diameter of the first refrigerant pipeline 1 is smaller than the inner diameter of the secondary refrigerant pipeline 2, and the inner wall and / or outer wall of one or all of the secondary refrigerant pipeline 2 and the first refrigerant pipeline 1 are surface-strengthened teeth. Of course, other numbers of refrigerant pipelines and secondary refrigerant pipelines 2 can also be set. In this case, the number of refrigerant pipelines can be one more or two more than the number of secondary refrigerant pipelines 2, or the number of refrigerant pipelines can be one less or two less than the number of secondary refrigerant pipelines 2. By having one more refrigerant pipeline than the number of secondary refrigerant pipelines 2, the refrigerant pipeline and the secondary refrigerant pipeline 2 can be fully utilized.

[0038] Each refrigerant pipeline is provided with at least two refrigerant openings, and the connecting pipeline 10 connects the refrigerant openings located on different refrigerant pipelines; each secondary refrigerant pipeline 2 is provided with at least two secondary refrigerant openings.

[0039] See Figure 1The end of the first refrigerant pipeline 1 is provided with a first refrigerant opening 6 and a second refrigerant opening 7 which are set far away from each other, the side of the second refrigerant pipeline 3 is provided with a third refrigerant opening 8 and a fourth refrigerant opening 9 which are set far away from each other, and the side of the secondary refrigerant pipeline 2 is provided with a first secondary refrigerant opening 4 and a second secondary refrigerant opening 5 which are set far away from each other, wherein the first refrigerant opening 6, the third refrigerant opening 8, and the first secondary refrigerant opening 4 are set close to each other, the second refrigerant opening 7, the fourth refrigerant opening 9, and the second secondary refrigerant opening 5 are set close to each other, and the connecting pipeline 10 connects the second refrigerant opening 7 and the fourth refrigerant opening 9 which are set close to each other. At this time, the refrigerant enters the first refrigerant pipeline 1 through the first refrigerant opening 6, and then enters the second refrigerant pipeline 3 through the connecting pipeline 10, and is finally discharged through the third refrigerant opening 8. The secondary refrigerant enters the secondary refrigerant pipeline 2 through one of the first secondary refrigerant opening 4 and the second secondary refrigerant opening 5, and is discharged through the other of the two. As an alternative embodiment, such as Figure 6 As shown, the connecting pipe 10 connects the first refrigerant opening 6 and the third refrigerant opening 8 which are arranged close to each other. At this time, the refrigerant enters the first refrigerant pipe 1 through the second refrigerant opening 7, then enters the second refrigerant pipe 3 through the connecting pipe 10, and is finally discharged through the fourth refrigerant opening 9. Of course, it is also possible to arrange that the connecting pipe 10 connects the first refrigerant opening 6 and the fourth refrigerant opening 9 which are arranged close to each other, or that the connecting pipe 10 connects the second refrigerant opening 7 and the third refrigerant opening 8 which are arranged close to each other, or when the number of refrigerant openings arranged on the refrigerant pipe is more than the number required to be used and / or the number of secondary refrigerant openings arranged on the secondary refrigerant pipe 2 is more than the number required to be used, the excess refrigerant openings and / or secondary refrigerant openings required to be used can be covered by an auxiliary structure such as a cover, and the auxiliary structure can be removed when needed.

[0040] In the refrigerant pipe and the secondary coolant pipe 2, the pipe portion located on the inner side is exposed to the adjacent pipe located on the outer side. The refrigerant opening is provided in the exposed portion of the refrigerant pipe, and / or the secondary coolant opening is provided in the exposed portion of the secondary coolant pipe 2. This facilitates the arrangement of the refrigerant opening and the secondary coolant opening. Figure 1 In the refrigerant pipe and the secondary coolant pipe 2, the end of the pipe located on the inner side is exposed at the end of the adjacent pipe located on the outer side. At this time, the first refrigerant opening 6 and the second refrigerant opening 7 are respectively provided at the two exposed ends of the first refrigerant pipe 1, the third refrigerant opening 8 and the fourth refrigerant opening 9 are provided on the side of the second refrigerant pipe 3, and the first secondary coolant opening 4 and the second secondary coolant opening 5 are provided on the exposed side of the secondary coolant pipe 2. And as Figure 1As shown, the first coolant opening 4, the second coolant opening 5, the third refrigerant opening 8, and the fourth refrigerant opening 9 are provided with connecting sleeves 15 to facilitate the connection of pipelines such as those passing through and discharging a coolant source or a refrigerant source. Of course, depending on the requirements of use, the connecting sleeves 15 may not be provided.

[0041] In a coaxial heat exchanger of the present invention, the refrigerant enters from one refrigerant pipeline to another refrigerant pipeline and always exchanges heat with the refrigerant in the refrigerant pipeline 2, thereby realizing a mixed process 14 instead of the single process 13 in the prior art, wherein the single process 13 refers to the process in which the refrigerant enters a refrigerant pipeline through the refrigerant inlet 11 and is discharged through the refrigerant outlet 12, and the mixed process 14 refers to the process in which the refrigerant enters multiple refrigerant pipelines through multiple refrigerant openings and connecting pipelines. Through the strengthening effect of the mixed process 14 of the coaxial heat exchanger, the flow velocity change of the refrigerant in the heat exchanger is increased, the turbulence is increased, and the heat transfer coefficient and heat transfer amount of the overall heat exchanger are increased. When used as an evaporator, such as Figure 4 As shown, in the mixed process 14, the difference between the saturation temperature of the refrigerant and the refrigerant temperature in the heat exchanger is large, which effectively ensures superheat, thereby improving the convective heat transfer and the heat transfer performance of the heat exchanger, and the convective heat transfer process is divided into a phase change zone and a superheat zone, the heat transfer coefficient of the phase change zone is large, and the heat transfer coefficient of the superheat zone is low. By using the mixed process 14, that is, the refrigerant exchanges heat with the refrigerant multiple times, it can be effectively guaranteed that: when the refrigerant is in the gas-liquid two-phase, the density is large, the required channel is small, the flow rate is increased, and the heat transfer is improved; when the refrigerant is in the gas phase, the density is small, and a larger channel is required to reduce the pressure drop and increase the outlet saturation temperature. Because the temperature difference of the countercurrent is large, superheat is more likely to be generated, so that the heat transfer area required under the same heat transfer conditions is smaller, and the volume of the heat exchanger is also reduced. While maintaining the same volume as the single-process heat exchanger, the heat transfer area of ​​the phase change zone is effectively increased, so that the heat transfer coefficient is highly efficient throughout the process, thereby being able to adapt to higher heat transfer requirements; when used as a condenser, such as Figure 5 As shown, the mixed process 14 effectively improves the shortcomings of the refrigerant in the first half, such as low density, high flow rate, and high pressure drop, and in the second half, high density, low flow rate, and low heat transfer coefficient, thereby improving the convective heat transfer and the heat exchange performance of the heat exchanger. The convective heat transfer process is divided into a phase change zone and a supercooling zone. The heat transfer coefficient in the phase change zone is large, and the heat transfer coefficient in the supercooling zone is low. Through the mixed process 14, that is, the refrigerant exchanges heat with the refrigerant multiple times, it can be effectively guaranteed that: when the refrigerant is in the gas phase, the density is small, and a larger channel is required to reduce the pressure drop and improve the heat exchange. When the refrigerant is in the gas-liquid two-phase, the density is large, and a small channel is required, which increases the flow rate and improves the heat exchange. Due to the two convective heat exchanges, the supercooling degree is effectively guaranteed, thereby improving the convective heat transfer and the heat exchange performance of the heat exchanger.

[0042] Example 2

[0043] This embodiment provides an evaporator for performing evaporative heat exchange of a refrigerant in a refrigeration system, including the coaxial heat exchanger in Embodiment 1, and using the coaxial heat exchanger to perform heat exchange between the refrigerant and the coolant.

[0044] Example 3

[0045] This embodiment provides a condenser for condensing and exchanging heat between refrigerant in a refrigeration system, including the coaxial heat exchanger in Example 1, and using the coaxial heat exchanger to exchange heat between the refrigerant and the coolant.

[0046] Example 4

[0047] This embodiment provides a refrigeration system, including the evaporator in embodiment 2 and / or the condenser in embodiment 3, and uses the above evaporator and / or condenser to perform evaporation or condensation heat exchange of refrigerant.

[0048] Obviously, the above embodiments are merely examples for clarity of explanation and are not intended to limit the implementation methods. Those skilled in the art will readily appreciate that other variations or modifications based on the above descriptions are possible. It is not necessary and impossible to enumerate all implementation methods here. Obvious variations or modifications arising therefrom remain within the scope of protection of the present invention.

Claims

1. A coaxial heat exchanger, characterized in that: It includes at least one connecting pipeline, at least one secondary coolant pipeline and multiple refrigerant pipelines, the secondary coolant pipeline and the refrigerant pipeline are coaxially arranged, the refrigerant pipeline is respectively provided with the inner side and the outer side of the secondary coolant pipeline, and the refrigerant pipelines are connected by the connecting pipeline; each of the refrigerant pipelines is respectively provided with at least two refrigerant openings, and the connecting pipeline connects the refrigerant openings located on different refrigerant pipelines; in the refrigerant pipeline and the secondary coolant pipeline, the pipeline part located on the inner side is exposed to its adjacent pipeline located on the outer side; the refrigerant opening is provided in the exposed part of the refrigerant pipeline, and the number of the refrigerant pipelines is one more than the number of the secondary coolant pipelines.

2. The coaxial heat exchanger according to claim 1, characterized in that: Each of the brine pipelines is provided with at least two brine openings.

3. The coaxial heat exchanger according to claim 2, characterized in that: In the refrigerant pipe and the brine pipe, an end portion of the pipe located on the inner side is exposed from an end portion of the adjacent pipe located on the outer side.

4. The coaxial heat exchanger according to claim 2, characterized in that: The brine opening is provided at the exposed portion of the brine pipeline.

5. The coaxial heat exchanger according to claim 4, characterized in that: There are two refrigerant pipelines and one secondary coolant pipeline.

6. An evaporator, characterized in that: The coaxial heat exchanger comprises the coaxial heat exchanger according to any one of claims 1 to 5.

7. A condenser, characterized in that: The coaxial heat exchanger comprises the coaxial heat exchanger according to any one of claims 1 to 5.

8. A refrigeration system, characterized in that: Comprising the evaporator according to claim 6 and / or the condenser according to claim 7.

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