An evaporator for low boiling point working fluid and a heat pump system

Abstract

The application discloses an evaporator and a heat pump system for low-boiling working medium. The evaporator comprises a sleeve, a steam inlet, a heat exchange tube bundle, a steam regulating assembly, a liquid atomizing assembly and a gas-liquid separation assembly. The sleeve is provided with end covers at both ends. The steam inlet is arranged on any end cover. The heat exchange tube bundle is arranged in the sleeve. The steam regulating assembly is arranged directly below the steam inlet and on the opening side of the heat exchange tube bundle, used for reducing the steam inflow speed of the heat exchange tube bundle and for controlling the uniform inflow of the steam into the heat exchange tube bundle. The liquid atomizing assembly is arranged on the circumferential outer wall of the sleeve, used for inputting refrigerant and uniformly distributing the refrigerant around the heat exchange tube bundle. The gas-liquid separation assembly is arranged on the circumferential outer wall of the sleeve and is spaced from the liquid atomizing assembly, used for outputting the evaporated refrigerant and preventing the refrigerant from carrying liquid. The evaporator improves the heat exchange efficiency and the heat exchange is uniform.

Description

Technical Field

[0001] This application relates to the field of evaporation equipment, and more particularly to an evaporator and heat pump system for low-boiling-point working fluids. Background Technology

[0002] The evaporator is a core component in a heat pump system, used in conjunction with the compressor, and its structural design directly affects the unit's performance. In traditional geothermal heating systems, the low-boiling-point working fluid needs to exchange heat with water in a heat exchanger before the water enters the heat pump system for further heat exchange and circulation. This significantly reduces the efficiency of the geothermal heat extraction system.

[0003] In commercially available evaporators, during operation, the refrigerant liquid on the shell side undergoes a phase change and evaporates, while the liquid or gaseous material on the other side only experiences a temperature change. Since latent heat is much greater than sensible heat, traditional evaporators often require large-size structures or dense tube arrangements to meet high heat exchange requirements. Furthermore, the large volume and rapid flow of refrigerant liquid entering through the throttling device make the heat exchange tubes closer to the inlet more effective than those further away, resulting in uneven heating on the condenser side and severely impacting heat exchange efficiency. Simultaneously, the drastic change in volumetric flow rate after the refrigerant phase change can cause the rapidly exiting refrigerant to carry liquid into the compressor, potentially causing liquid slugging damage. On the other hand, the high initial vapor velocity on the condenser side leads to most of the vapor entering the upper heat exchange tubes, increasing the difficulty of tube arrangement.

[0004] Therefore, how to promote uniform heat exchange inside the tube while improving heat exchange efficiency is a technical problem that needs to be solved by those skilled in the art. Summary of the Invention

[0005] The purpose of this application is to provide an evaporator and a heat pump system for low-boiling-point working fluids. This evaporator not only improves heat exchange efficiency but also promotes uniform heat exchange.

[0006] To achieve the above objectives, this application provides the following solution:

[0007] An evaporator for low-boiling-point refrigerants includes a sleeve, a steam inlet, a heat exchange tube bundle, a steam regulating component, a liquid atomizing component, and a gas-liquid separation component. The sleeve has end caps at both ends. The steam inlet is located at either end cap. The heat exchange tube bundle is located inside the sleeve. The steam regulating component is located directly below the steam inlet and on the open side of the heat exchange tube bundle, used to reduce the rate at which steam flows into the heat exchange tube bundle and to control the uniform flow of steam into the heat exchange tube bundle. The liquid atomizing component is located on the circumferential outer wall of the sleeve, used to input the refrigerant and to evenly distribute the refrigerant around the heat exchange tube bundle. The gas-liquid separation component is located on the circumferential outer wall of the sleeve, spaced apart from the liquid atomizing component, used to output the evaporated refrigerant and to prevent the refrigerant from carrying liquid.

[0008] Preferably, the steam regulating assembly includes a horizontal plate, which is horizontally disposed inside the end cover. The horizontal plate has through holes around its perimeter, and the center of the horizontal plate is directly opposite the steam inlet, in order to reduce the rate at which steam flows into the heat exchange tube bundle.

[0009] Preferably, the steam regulating assembly further includes a vertical block and a curved block. The vertical block is vertically disposed on the horizontal plate and located below the horizontal block; the curved block is vertically disposed on the horizontal plate and perpendicular to the vertical block. The horizontal plate, the vertical block, and the curved block together form four areas of the same size, which are used to divert the steam flowing into the heat exchange tube bundle.

[0010] Preferably, the through hole includes a first hole and a second hole. The first hole is located in the region of the horizontal plate near the opening of the heat exchange tube bundle; the second hole is located in the region of the horizontal plate away from the opening of the heat exchange tube bundle. The first hole is smaller than the second hole so that steam flows into the heat exchange tube bundle evenly.

[0011] Preferably, the liquid atomizing component includes a distribution pipe, an inlet pipe, and pipelines, with the inlet pipe connected to the distribution pipe; one end of each pipeline is connected to the distribution pipe, and the other end is connected to the sleeve, with the pipelines used to spray refrigerant into the sleeve in the form of droplets.

[0012] Preferably, the pipeline includes an inlet channel, a cavity, an inlet, and a nozzle. The inlet channel is connected to the distribution pipe. The cavity is connected to the inner wall of the inlet channel and is located at the end of the inlet channel away from the distribution pipe. The inner cavity of the cavity is oriented towards the sleeve. The inlet connects the cavity and the inlet channel. Multiple inlets are located sequentially on the tangent of a point on the inner wall of the cavity, and all inlets are arranged in a swirling pattern. The nozzle connects to the inner cavity, and the taper of the nozzle is 80°-100°.

[0013] Preferably, the gas-liquid separation component includes a housing, baffles, and filters, with the housing connected to a sleeve; multiple baffles are spaced apart inside the housing and located near the sleeve end of the housing to reduce the refrigerant flow rate; multiple filters are spaced apart inside the housing and located above the baffles to change the flow direction of the refrigerant, thereby increasing the gas-liquid separation efficiency.

[0014] Preferably, all baffles are connected to the inner wall of the shell at one end and suspended at the other end, and adjacent baffles are staggered.

[0015] Preferably, the filter screen has at least two rows of arched guide holes, the two rows of holes are staggered, and the outlets of the two rows of holes are close to each other.

[0016] A heat pump system includes the aforementioned evaporator for a low-boiling-point working fluid.

[0017] Compared to the aforementioned background technology, this application adds a steam regulating component. The steam regulating component does not have a central through-hole, and the center is directly opposite the steam inlet. Through-holes are provided around the perimeter, but their sizes differ; the through-holes closer to the heat exchange tube bundle opening are smaller, while those further away are larger. This not only reduces the rate at which steam flows into the heat exchange tube bundle but also controls the uniform flow of steam into the heat exchange tube bundle. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this application. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the overall structure of the evaporator in this application;

[0020] Figure 2 This is a schematic diagram of the overall structure of the steam conditioning assembly of the evaporator in this application;

[0021] Figure 3 This is a schematic diagram of the overall structure of the liquid atomization component of the evaporator in this application;

[0022] Figure 4 This is a cross-sectional view of the liquid atomization component piping structure of the evaporator in this application;

[0023] Figure 5 This is a cross-sectional view of the liquid atomization component piping structure of the evaporator in this application;

[0024] Figure 6 This is a cross-sectional view of the overall structure of the gas-liquid separation component of the evaporator in this application;

[0025] Figure 7 This is a schematic diagram of the filter screen structure of the gas-liquid separation component of the evaporator in this application.

[0026] in:

[0027] 10 is a sleeve, 20 is a steam inlet, 30 is a steam regulating component, 31 is a horizontal plate, 311 is the first hole, 312 is the second hole, 32 is a vertical block, 33 is a bend, 40 is a liquid atomizing component, 41 is an inlet pipe, 42 is a distribution pipe, 43 is a pipeline, 431 is an inlet channel, 432 is a liquid inlet, 433 is a cavity, 434 is a nozzle, 50 is a gas-liquid separation component, 51 is a shell, 52 is a baffle plate, 53 is a filter screen, 531 is a guide hole, 60 is a heat exchange tube bundle, 70 is a left end cover, 80 is a right end cover, 90 is a liquid outlet, 100 is a saddle, and 110 is an oil drain port. Detailed Implementation

[0028] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0029] To enable those skilled in the art to better understand the present application, the present application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0030] An evaporator for low-boiling-point working fluid includes a sleeve 10, a steam inlet 20, a heat exchange tube bundle 60, a steam regulating component 30, a liquid atomizing component 40, and a gas-liquid separation component 50. The sleeve 10 has end caps at both ends; the steam inlet 20 is located at either end cap; the heat exchange tube bundle 60 is located inside the sleeve 10; the steam regulating component 30 is located directly below the steam inlet 20 and on the opening side of the heat exchange tube bundle 60, used to reduce the rate at which steam flows into the heat exchange tube bundle 60 and to control the uniform flow of steam into the heat exchange tube bundle 60; the liquid atomizing component 40 is located on the circumferential outer wall of the sleeve 10, used to input the refrigerant and to evenly distribute the refrigerant around the heat exchange tube bundle 60; the gas-liquid separation component 50 is located on the circumferential outer wall of the sleeve 10, spaced apart from the liquid atomizing component 40, used to output the evaporated refrigerant and to prevent the refrigerant from carrying liquid.

[0031] Specifically, with attachment Figure 1 With the orientation as a reference, the sleeve 10 is a horizontal cylindrical shape with a left end cap 70 and a right end cap 80 at both ends. The steam inlet 20 is located above the right end cap 80, and the steam regulating component 30 is located inside the right end cap 80. The gas-liquid separation component 50 and the liquid atomizing component 40 are both located in the center above the sleeve 10. The heat exchange tube bundle 60 is horizontally located below the sleeve 10 and is connected to the sleeve 10. Steam flows from the right end of the heat exchange tube bundle 60 to the left end of the heat exchange tube bundle 60. At the same time, a liquid outlet 90 is located below the left end cap 70, and an oil drain port 110 is located below the sleeve 10. The sleeve 10 is supported by the saddle 100.

[0032] Furthermore, the specific working process is as follows: the high-temperature steam that needs to be cooled enters through the steam inlet 20 at the right end, enters the heat exchange tube bundle 60 through the steam regulating component 30 in the right end cover 80, and then flows out from the liquid outlet 90 below the left end cover 70; at the same time, the refrigerant enters the sleeve 10 from the inlet pipe 41 on the liquid atomizing device, and after phase change evaporation, flows out through the shell 51 on the gas-liquid separation device.

[0033] In the embodiments of this application, the steam regulating assembly 30 includes a horizontal plate 31, which is horizontally disposed inside the end cover. The horizontal plate 31 has through holes around its perimeter, and the center of the horizontal plate 31 is directly opposite the steam inlet 20, which is used to reduce the rate at which steam flows into the heat exchange tube bundle 60.

[0034] Specifically, with attachment Figure 2 With the orientation as a reference, the horizontal plate 31 is horizontally connected to the inner wall of the right end cover 80. The horizontal plate 31 has an unperforated area to reduce the inlet steam velocity and prevent the condensation time in the heat exchange tube bundle 60 from being too short due to excessively high steam velocity, resulting in insufficient heat exchange. The area of ​​the unperforated area is 2-3 times the cross-sectional area of ​​the steam inlet and is located directly below the steam inlet, which can effectively reduce the flow rate of high-temperature steam entering the evaporator.

[0035] In the embodiments of this application, the steam regulating assembly 30 further includes a vertical block 32 and a bent block 33. The vertical block 32 is vertically disposed on the horizontal plate 31 and located below the horizontal block; the bent block 33 is vertically disposed on the horizontal plate 31 and perpendicular to the vertical block 32. The horizontal plate 31, the vertical block 32 and the bent block 33 constitute four regions of the same size, which are used to divert the steam flowing into the heat exchange tube bundle 60.

[0036] Specifically, with attachment Figure 2 With the orientation as a reference, the bent plate is set perpendicular to the vertical plate and is welded to the right end cover 80 to form four independent areas. Two areas face the heat exchange tube bundle 60, while the other two areas face away from it. Steam in the two areas facing the heat exchange tube bundle 60 can flow directly into the corresponding heat exchange pipes, while steam in the two areas facing away from the heat exchange tube bundle 60 flows from both sides into the heat exchange pipes near the edge of the sleeve 10. This ensures that the steam is evenly distributed throughout all the heat exchange pipes.

[0037] The division of the zones works in conjunction with the baffles. Three baffles divide the heat exchange tube bundle 60 inlet into four zones, or four baffles divide the heat exchange tube bundle 60 inlet into six zones, and so on. The more zones the better, but more zones will make manufacturing and installation more complicated.

[0038] In the embodiments of this application, the through hole includes a first hole 311 and a second hole 312. The first hole 311 is located in the region of the horizontal plate 31 near the opening of the heat exchange tube bundle 60; the second hole 312 is located in the region of the horizontal plate 31 away from the opening of the heat exchange tube bundle 60. The first hole 311 is smaller than the second hole 312 so that steam flows into the heat exchange tube bundle 60 evenly.

[0039] Specifically, the diameter of the first hole 311 at the end of the horizontal plate 31 near the inlet of the heat exchange tube bundle 60 is smaller than the diameter of the second hole 312 at the end away from the inlet of the heat exchange tube bundle 60. That is, the diameter of the through holes in the two regions facing the heat exchange tube bundle 60 is smaller than the diameter of the through holes in the two regions away from the heat exchange tube bundle 60. Since the flow rate is greater in the region near the steam inlet 20, and the first hole 311 has greater resistance to the fluid than the second hole 312, this structure can ensure a uniform steam flow rate into the heat exchange tube bundle 60, improve heat exchange efficiency, and make the tube arrangement of the heat exchange tube bundle 60 more convenient and faster.

[0040] In other words, it is equivalent to dividing the heat exchange tube bundle 60 inlet into four regions by three baffles, and then distributing the flow rate of the four regions equally by using different orifice diameters on the baffles.

[0041] In the embodiments of this application, the liquid atomizing component 40 includes a distribution pipe 42, an inlet pipe 41, and pipes 43. The inlet pipe 41 is connected to the distribution pipe 42. One end of each pipe 43 is connected to the distribution pipe 42, and the other end is connected to the sleeve 10. The pipes 43 are used to spray refrigerant into the sleeve 10 in the form of droplets.

[0042] For details, please refer to the appendix. Figure 3 The refrigerant enters the distribution pipe 42 through the inlet pipe 41 and then passes through the distribution pipe 42, which distributes the refrigerant evenly into each pipe 43. Finally, the refrigerant flows into the sleeve 10 through each pipe 43 and is distributed near the heat exchange tube bundle 60.

[0043] In the embodiments of this application, the pipeline 43 includes an inlet channel 431, a cavity 433, an inlet port 432, and a nozzle 434. The inlet channel 431 is connected to the distribution pipe 42. The cavity 433 is connected to the inner wall of the inlet channel 431 and is located at the end of the inlet channel 431 away from the distribution pipe 42. The inner cavity of the cavity 433 is arranged facing the sleeve 10. The inlet port 432 connects the cavity 433 and the inlet channel 431. Multiple inlets 432 are located sequentially on the tangent of a point on the inner wall of the cavity 433, and all inlets 432 are arranged in a swirling pattern. The nozzle 434 is connected to the inner cavity, and the taper of the nozzle 434 can be set to 80°-100°.

[0044] For details, please refer to the appendix. Figure 3-5 The liquid enters through inlet channel 431 and is then injected into cavity 433 through inlet port 432. It gains rotational motion and forms an air column at the center of the water flow. The air column then exits from nozzle 434 in an unstable film state, breaking into droplets under the influence of gas dynamic pressure, surface tension, and viscosity. This atomizes the refrigerant before it enters the heat exchange space, enhancing the refrigerant's thorough and uniform contact with the heat exchange tubes in all directions, promoting uniform heat exchange, and preventing excessive local temperature differences that could cause violent boiling.

[0045] Among them, the taper of nozzle 434 is in the range of 80 to 100°, the ratio of nozzle 434 outlet length to diameter is 2-3, and the ratio of cavity 433 inner wall diameter to inlet 432 diameter is 3-4.

[0046] In the embodiments of this application, the gas-liquid separation component 50 includes a housing 51, baffles 52, and filters 53. The housing 51 is connected to the sleeve 10. Multiple baffles 52 are spaced apart inside the housing 51 and located at one end of the housing 51 near the sleeve 10 to reduce the refrigerant flow rate. Multiple filters 53 are spaced apart inside the housing 51 and located above the baffles 52 to change the flow direction of the refrigerant, thereby increasing the gas-liquid separation efficiency.

[0047] Specifically, the casing 51 is funnel-shaped. The gaseous refrigerant passes through the baffle 52, then through the filter screen 53, and finally flows out. The baffle 52 is used to reduce the outlet velocity of the refrigerant gas to prevent the high-speed gas after vaporization from impacting the filter screen 53 and causing deformation of the filter screen 53 mesh.

[0048] In the embodiments of this application, all the baffles 52 are connected to the inner wall of the housing 51 at one end and suspended at the other end, and adjacent baffles 52 are staggered.

[0049] Specifically, with attachment Figure 6 With the orientation as a reference, there are three baffles 52 in total, two on the right and one on the left. The baffle 52 on the left is located between them, and the length of the baffle 52 is greater than the radius of the inner wall where the baffle 52 is located. The length of the baffle 52 gradually decreases from the upper end to the lower end of the shell 51.

[0050] In the embodiments of this application, the filter screen 53 has at least two rows of arched guide holes 531, the two rows of holes are staggered, and the outlets of the two rows of holes are close to each other.

[0051] Specifically, the housing 51 contains three layers of filter screens 53, each circular in shape, made of aluminum foil or stainless steel. Each filter screen 53 has several sets of guide holes 531 arranged side-by-side, with each set spaced apart parallel to the diameter of the filter screen 53. Every two sets of guide holes 531 are arranged diagonally at 180° angles, overlapping each other at the correct angle. Simultaneously, the guide holes 531 on the filter screen 53 are arranged from bottom to top within the housing 51, with the diameter decreasing from coarse to fine. This causes the gaseous refrigerant to change its flow direction multiple times as it passes through, effectively reducing the outlet velocity of the gaseous refrigerant and increasing the efficiency of gas-liquid separation.

[0052] In this way, the flow direction of the gaseous refrigerant is changed multiple times when it passes through the gas-liquid separation device, which increases the efficiency of gas-liquid separation. The separated droplets can fall back into the liquid refrigerant under the action of gravity, achieving secondary evaporation and effectively preventing the refrigerant in droplet state from being sucked into the heat pump system.

[0053] The heat pump system provided in this application has an evaporator for a low-boiling-point working fluid, including the evaporator described in the above specific embodiments; other parts of the heat pump system can be referred to in the prior art, and will not be elaborated here.

[0054] It should be noted that in this specification, relational terms such as first and second are used only to distinguish one entity from several other entities, and do not necessarily require or imply any such actual relationship or order between these entities.

[0055] This document uses specific examples to illustrate the principles and implementation methods of this application. The descriptions of the embodiments above are only for the purpose of helping to understand the method and core ideas of this application. It should be noted that those skilled in the art can make several improvements and modifications to this application without departing from the principles of this application, and these improvements and modifications also fall within the protection scope of the claims of this application.

Claims

1. An evaporator for low-boiling-point working fluids, characterized in that, include: A sleeve with end caps at both ends; A steam inlet is located at any of the aforementioned end caps; A heat exchange tube bundle is disposed inside the sleeve; A steam regulating component, located directly below the steam inlet and on one side of the opening of the heat exchange tube bundle, is used to reduce the rate at which steam flows into the heat exchange tube bundle and to control the uniform flow of steam into the heat exchange tube bundle. The steam regulating component includes: A horizontal plate is horizontally disposed inside the end cover. The horizontal plate has through holes around its perimeter and its center is directly opposite the steam inlet, which is used to reduce the rate at which steam flows into the heat exchange tube bundle. A vertical block is positioned perpendicularly to the horizontal plate and located below the horizontal plate; The bend is vertically disposed on the horizontal plate and perpendicular to the vertical block. The horizontal plate, the vertical block and the bend form four areas of the same size, which are used to divert the steam flowing into the heat exchange tube bundle. A liquid atomizing component is disposed on the circumferential outer wall of the sleeve for introducing refrigerant and distributing the refrigerant evenly around the heat exchange tube bundle; A gas-liquid separation component is disposed on the circumferential outer wall of the sleeve and spaced apart from the liquid atomizing component, for outputting the evaporated refrigerant and preventing the refrigerant from carrying liquid; The through hole includes: The first hole is located in the area of ​​the horizontal plate near the opening of the heat exchange tube bundle; The second hole is located in the area of ​​the horizontal plate away from the opening of the heat exchange tube bundle. The first hole is smaller than the second hole so that the steam flows into the heat exchange tube bundle evenly.

2. The evaporator for low-boiling-point working fluids according to claim 1, characterized in that, The liquid atomizing component includes: Distribution pipe; The inlet pipe is connected to the distribution pipe; The pipeline has one end connected to the distribution pipe and the other end connected to the sleeve. The pipeline is used to spray the refrigerant into the sleeve in the form of droplets.

3. The evaporator for low-boiling-point working fluids according to claim 2, characterized in that, The pipeline includes: The inlet channel is connected to the distribution pipe; A cavity is connected to the inner wall of the inlet channel and is located at the end of the inlet channel away from the distribution pipe, with the inner cavity of the cavity facing the sleeve; The liquid inlet connects the cavity and the inlet channel. Multiple liquid inlets are located sequentially on the tangent of a point on the inner wall of the cavity, and all liquid inlets are arranged in a swirling pattern. A nozzle, connected to the inner cavity, has a taper of 80°-100°.

4. The evaporator for low-boiling-point working fluids according to claim 1, characterized in that, The gas-liquid separation component includes: The housing is connected to the sleeve; A plurality of baffles are spaced apart inside the housing and located at one end of the housing near the sleeve, for reducing the refrigerant flow rate; Multiple filter screens are spaced apart inside the housing and located above the baffle plate to change the flow direction of the refrigerant, thereby increasing the gas-liquid separation efficiency.

5. The evaporator for low-boiling-point working fluids according to claim 4, characterized in that, All of the baffles are connected at one end to the inner wall of the housing, and the other end is suspended in the air, with adjacent baffles being staggered.

6. The evaporator for low-boiling-point working fluids according to claim 4, characterized in that, The filter screen has at least two rows of arched guide holes, the two rows of holes are staggered, and the outlets of the two rows of holes are close to each other.

7. A heat pump system, characterized in that, Includes the evaporator for low-boiling-point working fluids as described in any one of claims 1-6.

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