A high-flux heat pipe evaporator for heat pumps

Abstract

The utility model relates to heat exchange equipment technical field, concretely relates to a high flux heat pipe evaporator for heat pump, including the casing, the inside of casing is equipped with hot side hole plate and cold side hole plate, and hot side hole plate and cold side hole plate divide the shell inner chamber into hot side cavity and cold side cavity, the hot side cavity and the cold side cavity do not communicate with each other, and the physical isolation of waste heat carrier and heat pump working medium is realized simultaneously, avoids the failure of whole heat exchange system because of corrosion wear and tear leakage problem, a plurality of heat pipes, the heat pipe passes through the through -hole of hot side hole plate and the cold side hole plate and is equipped with, makes the hot side cavity and the cold side cavity do not communicate with each other, the heat pipe includes hot side pipe body and cold side pipe body, the hot side pipe body passes through hot side hole plate, and the cold side pipe body passes through cold side hole plate, the adjacent end of hot side pipe body and cold side pipe body is detachably connected, makes hot side pipe body and cold side pipe body communicate, when hot side pipe body is worn and corroded, only causes the loss of single heat pipe heat exchange load, and can realize quick replacement.

Description

Technical Field

[0001] This utility model relates to the field of heat exchange equipment technology, specifically to a high-throughput heat pipe evaporator for heat pumps. Background Technology

[0002] Low-temperature waste heat recovery is a current research focus in the industrial field, and heat pump technology can upgrade low-grade waste heat to high-grade heat. At present, heat pump technology is mainly used to extract heat from low-temperature waste heat carriers, raise the temperature and improve the quality to generate high-temperature heat for use in other processes in the plant, or produce steam for external sale.

[0003] Evaporators are key equipment in heat pump systems used to extract heat from low-temperature waste heat. They typically use high-pressure organic refrigerants or inorganic refrigerants such as carbon dioxide and ammonia. However, in low-temperature waste heat utilization, the heat transfer medium is often flue gas, wastewater, or other media containing solid particles and corrosive components. Since the pressure of the commonly used refrigerant inside the evaporator is generally above 3 bar, corrosion or wear can cause rapid leakage of the refrigerant, leading to system failure.

[0004] In one scenario, industrial processes use an intermediate fluid to exchange heat from the waste heat carrier before it enters the evaporator to exchange heat with the heat pump working fluid. While this indirect heat extraction method can avoid heat pump system failure caused by wear and corrosion, the additional circulation pump and circulation pipelines increase equipment complexity, and the two heat exchanges increase additional temperature difference losses, leading to a decrease in the evaporation temperature of the heat pump and a deterioration in the overall performance of the heat pump.

[0005] In another scenario, industrial applications use more corrosion-resistant and wear-resistant materials to manufacture evaporators. However, materials that are corrosion-resistant, wear-resistant, and have high thermal conductivity are often very expensive, increasing the overall cost of heat pumps and limiting their widespread adoption. Utility Model Content

[0006] To address the aforementioned problems, the purpose of this invention is to provide a high-flux heat pipe evaporator for heat pumps.

[0007] The technical solution provided by this utility model is as follows:

[0008] A high-flux heat pipe evaporator for heat pumps, comprising:

[0009] The housing has a hot-side perforated plate and a cold-side perforated plate inside, which divide the inner cavity of the housing into a hot-side cavity and a cold-side cavity;

[0010] Multiple heat pipes pass through through holes provided in the hot-side perforated plate and the cold-side perforated plate, so that the hot-side cavity and the cold-side cavity are not connected to each other;

[0011] The heat pipe includes a hot-side pipe and a cold-side pipe; wherein: the hot-side pipe passes through a hot-side orifice plate, and the cold-side pipe passes through a cold-side orifice plate; the adjacent ends of the hot-side pipe and the cold-side pipe are detachably connected, so that the hot-side pipe and the cold-side pipe are connected.

[0012] As an optional technical solution, the hot-side tube body is interference-fitted with the hot-side orifice plate; the cold-side tube body is fixedly connected to the cold-side orifice plate.

[0013] As an optional technical solution, for the hot-side pipe body and the cold-side pipe body, one pipe body end is provided with an external thread and the other pipe body end is provided with an internal thread; the hot-side pipe body and the cold-side pipe body are connected by threads, and a sealing ring is provided at the connection.

[0014] Optionally, the hot-side pipe and the cold-side pipe form an internal space; the cold-side pipe is provided with an air extraction port, which can draw the internal space into a negative pressure; and the air extraction port can be sealed.

[0015] As an optional technical solution, a porous layer is provided on the outer surface of the cold-side tube.

[0016] Optionally, the thickness of the porous layer is 0.15 mm to 0.25 mm.

[0017] As an optional technical solution, heat-conducting fins are provided on the outer surface of the hot-side tube.

[0018] As an optional technical solution, a working fluid inlet is provided on the shell at the bottom of the cold side cavity; and a working fluid outlet is provided on the shell at the top of the cold side cavity.

[0019] Optionally, the working fluid inlet has multiple inlets, which are evenly distributed on the shell.

[0020] As an optional technical solution, the shell is provided with a waste heat carrier inlet and a waste heat carrier outlet that communicate with the hot side cavity; the shell located at the bottom of the hot side cavity is also provided with an ash discharge port.

[0021] Compared with the prior art, the technical solution provided by this utility model has the following advantages:

[0022] The high-flux heat pipe evaporator for heat pumps proposed in this invention includes multiple heat pipes, each comprising a detachable hot-side tube and a cold-side tube. When the hot-side tube is worn or corroded, only the heat exchange load of a single heat pipe is lost. Furthermore, the evaporator has non-communicating hot-side and cold-side cavities, achieving physical isolation between the waste heat carrier and the heat pump working fluid, preventing the entire heat exchange system from failing. In addition, the damaged hot-side tube can be replaced individually, thus making the proposed heat pipe evaporator highly economical to maintain.

[0023] In addition, the contact area between the hot end of the heat pipe and the waste heat carrier can be increased by fins to improve the heat extraction effect. At the cold end of the heat pipe, a sintered porous metal layer with a thickness of about 0.2 mm is used. Its wall thermal resistance will not increase significantly, but the porous structure can generate a large number of vaporization nuclei during the phase change of the heat pump working fluid, avoiding temperature difference loss due to overheating of the heat pump working fluid. At the same time, the formed bubbles can fully disturb the heat pump working fluid, thereby enhancing interphase heat and mass transfer and reducing the temperature difference between the heat pump working fluid and the waste heat carrier. Attached Figure Description

[0024] Figure 1 This is a front view of a high-flux heat pipe evaporator for a heat pump in one embodiment of this application;

[0025] Figure 2 This is a cross-sectional view of a high-flux heat pipe evaporator for a heat pump in one embodiment of this application;

[0026] Figure 3 for Figure 2 Enlarged view of point A in the middle;

[0027] Figure 4 This is a schematic diagram of the flow direction of each medium in one embodiment of this application;

[0028] Figure 5 This is a schematic diagram of the connection between the hot-side pipe and the cold-side pipe in one embodiment of this application;

[0029] Figure 6 This is a schematic diagram of a cold-side tube body with a porous layer in one embodiment of this application.

[0030] Explanation of the labels in the diagram:

[0031] Hot side cavity 101, waste heat carrier inlet 102, waste heat carrier outlet 103, ash discharge port 104, hot side perforated plate 105, cold side perforated plate 106;

[0032] Cold side cavity 201, working fluid outlet 202, working fluid inlet 203;

[0033] Hot side tube 301, cold side tube 302, sealing ring 303, air extraction port 304, porous layer 305. Detailed Implementation

[0034] To further understand the content of this utility model, a detailed description of this utility model will be provided in conjunction with the accompanying drawings and embodiments.

[0035] The structures, proportions, and sizes illustrated in the accompanying drawings are merely for illustrative purposes and to aid those skilled in the art in understanding and reading the invention. They are not intended to limit the scope of the invention and therefore have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to size, without affecting the effectiveness and purpose of the invention, should still fall within the scope of the technical content disclosed in this utility model. Furthermore, terms such as "upper," "lower," "left," "right," and "middle" used in this specification are merely for clarity and not intended to limit the scope of implementation. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of the invention's implementation.

[0036] In one embodiment, such as Figure 1 , Figure 2 , Figure 3 As shown, this application proposes a high-flux heat pipe evaporator for heat pumps. The high-flux heat pipe evaporator for heat pumps includes a shell. It should be noted that the shell in this application can be integrally formed or it can be formed by combining several independent parts, such as by assembling multiple plates.

[0037] A hot-side perforated plate 105 and a cold-side perforated plate 106 are provided inside the housing. The hot-side perforated plate 105 and the cold-side perforated plate 106 are directly or indirectly fixed to the housing. Most or all of the hot-side perforated plate 105 and the cold-side perforated plate 106 are located in the inner cavity of the housing, thereby dividing the inner cavity of the housing into a hot-side cavity 101 and a cold-side cavity 201.

[0038] It should be noted that the hot-side perforated plate 105 and the cold-side perforated plate 106 can be arranged side by side with intervals or roughly attached. In this case, the inner cavity of the housing on the side of the hot-side perforated plate 105 away from the cold-side perforated plate 106 is the hot-side cavity 101, and the inner cavity of the housing on the side of the cold-side perforated plate 106 away from the hot-side perforated plate 105 is the cold-side cavity 201. The hot-side cavity 101 and the cold-side cavity 201 are not connected to each other.

[0039] Both the hot-side orifice plate 105 and the cold-side orifice plate 106 are provided with multiple through holes. In this embodiment, the heat pipe evaporator also includes multiple heat pipes, which pass sequentially through the through holes provided on the hot-side orifice plate 105 and the cold-side orifice plate 106. That is, after the heat pipe passes through the through holes provided on the orifice plate, part of the heat pipe is located in the hot-side cavity 101 and part is located in the cold-side cavity 201. In this embodiment, the heat pipe includes a hot-side tube body 301 and a cold-side tube body 302. The part of the heat pipe located in the hot-side cavity 101 is called the hot-side tube body 301, which can also be called the hot end; the part located in the cold-side cavity 201 is called the cold-side tube body 302, which can also be called the cold end.

[0040] like Figure 4As shown, the hot end of the heat pipe contacts the waste heat carrier, and the cold end contacts the heat pump working fluid. The working fluid inside the heat pipe vaporizes upon heating at the hot end and rises to the cold end under buoyancy. Utilizing the heat pipe's superconducting properties, it rapidly transfers heat to the heat pump working fluid, which then vaporizes. The working fluid inside the heat pipe, having exchanged heat with the working fluid, condenses at the cold end. The condensed working fluid then returns to the hot end under gravity, completing the cycle. The waste heat carrier can be a medium containing solid particles or corrosive components, such as flue gas or wastewater; the heat pump working fluid can be R134a, R245fa, R717, or R718, etc.; and the working fluid inside the heat pipe can be water, ammonia, or alcohol, etc.

[0041] In this application, when the waste heat carrier enters the hot-side cavity 101 and the heat pump working fluid enters the cold-side cavity 201, physical isolation between the waste heat carrier and the heat pump working fluid can be achieved. Because multiple heat pipes are installed, when the portion of the heat pipe in the hot-side cavity 101 is worn or corroded, only the heat exchange load of that single heat pipe is lost. Furthermore, the physical isolation between the waste heat carrier and the heat pump working fluid prevents the entire heat exchange system from failing.

[0042] Based on the above scheme, the waste heat carrier and the heat pump working fluid exchange heat through heat pipes, avoiding the risk of leakage failure caused by wear and corrosion in indirect heat exchange, while avoiding the temperature difference loss and equipment complexity caused by using intermediate fluids for indirect heat exchange.

[0043] It should be noted that the hot-side tube 301 passes through the hot-side orifice plate 105, and the cold-side tube 302 passes through the cold-side orifice plate 106. The hot-side tube 301 may only be partially located within the hot-side cavity 101, with the remainder located in the space between the hot-side orifice plate 105 and the cold-side orifice plate 106. Similarly, the cold-side tube 302 may also only be partially located within the cold-side cavity 201, with the remainder located in the space between the hot-side orifice plate 105 and the cold-side orifice plate 106.

[0044] As an optional implementation, the adjacent ends of the hot-side tube 301 and the cold-side tube 302 are detachably connected. When the hot-side tube 301 is damaged, the damaged hot-side tube 301 can be disconnected from the corresponding cold-side tube 302, allowing only the damaged portion of the hot-side tube 301 to be replaced. Based on the above implementation, when the hot-side tube 301 within the hot-side cavity 101 is subjected to wear and corrosion, it is convenient to replace the damaged hot-side tube 301.

[0045] As an optional implementation, the hot-side pipe body 301 is interference-fitted with the hot-side orifice plate 105. During normal operation, due to thermal expansion and contraction, the hot-side pipe body 301 and the hot-side orifice plate 105 fit well and will not leak. During maintenance or replacement, the hot-side pipe body 301 can be separated from the hot-side orifice plate 105 by cooling, which facilitates flushing, maintenance, or replacement of the pipe surface.

[0046] Optionally, the cold-side tube 302 is fixedly connected to the cold-side orifice plate 106, for example, by welding. Since the cold-side tube 302 does not come into contact with the residual heat carrier, it is not easily subjected to wear and corrosion, so the cold-side tube 302 does not need to be easily disassembled.

[0047] Regarding the specific method of detachable connection between the hot-side tube 301 and the cold-side tube 302, as an optional embodiment, such as... Figure 5 As shown, one end of the hot-side pipe 301 and the cold-side pipe 302 has an external thread, and the other end has an internal thread. In this configuration, the hot-side pipe 301 and the cold-side pipe 302 can be connected by threads. The hot-side pipe 301 has a centrally located internal cavity, and the end of the internal cavity near the threaded connection of the hot-side pipe 301 has an opening. Similarly, the cold-side pipe 302 has a centrally located internal cavity, and the end of the internal cavity near the threaded connection of the cold-side pipe 302 has an opening. When the hot-side pipe 301 and the cold-side pipe 302 are connected by threads, the open end of the hot-side pipe 301 communicates with the open end of the cold-side pipe 302.

[0048] The above solution is an example. Other technical solutions in the prior art can also be used to achieve the detachable connection between the hot-side tube 301 and the cold-side tube 302.

[0049] To improve the sealing effect, a sealing ring 303, such as a rubber gasket, can be provided at the threaded connection between the hot-side tube body 301 and the cold-side tube body 302.

[0050] In some embodiments, the cold-side tube 302 is provided with an evacuation port 304. During installation and replacement, after the internal working fluid (generally water, ammonia, or alcohol) is filled into the tube space, the hot-side tube 301 and the cold-side tube 302 are connected by threads, with a rubber gasket between them. During installation, the gasket is squeezed to create a seal. Then, air is evacuated through the evacuation port 304 to ensure that the internal pressure of the heat pipe is at the saturation pressure of the corresponding medium at the design temperature. The evacuation port 304 is then sealed. Due to the internal negative pressure, the rubber gasket will maintain good airtightness under atmospheric pressure.

[0051] The 304 sealing method for the air extraction port is a relatively mature technology, and will not be elaborated or limited here.

[0052] In existing technologies, due to equipment costs and space limitations, it is impossible to achieve higher evaporation temperatures by increasing the heat exchange area indefinitely. Because of superheat, the heat pump working fluid often fails to undergo a phase change when it reaches the phase change temperature, resulting in additional temperature loss. Currently, a common practice is to groove the surface of the pipe on the heat pump working fluid side to increase vaporization nuclei and reduce superheat requirements, while simultaneously enhancing the heat transfer coefficient on that side. However, due to the high internal pressure of the evaporator, grooving the pipe surface not only increases processing difficulty and equipment costs, but also creates stress concentration points during processing, leading to a decrease in structural strength under repeated temperature changes and increasing the risk of internal working fluid leakage.

[0053] As an optional implementation scheme, such as Figure 6 As shown, a porous layer 305 is provided on the outer surface of the cold-side tube 302. Preferably, the thickness of the porous layer 305 is 0.15mm to 0.25mm, for example, 0.15mm, 0.18mm, 0.2mm, 0.23mm, or 0.25mm.

[0054] By sintering a porous metal layer at the cold end of the heat pipe, the wall thermal resistance does not increase significantly. However, the porous structure can generate a large number of vaporization nuclei during the phase change of the heat pump working fluid, avoiding temperature loss due to overheating of the heat pump working fluid. At the same time, the formed bubbles can fully disturb the heat pump working fluid, thereby enhancing interphase heat and mass transfer and reducing the temperature difference between the heat pump working fluid and the waste heat carrier.

[0055] As an optional implementation, heat-conducting fins can be provided on the outer surface of the hot-side tube 301 to increase the contact area and improve the heat extraction effect.

[0056] In one optional embodiment, a working fluid inlet 203 is provided on the shell located at the bottom of the cold-side cavity 201, through which heat pump working fluid can be supplied into the cold-side cavity 201. When heat pump working fluid is introduced through the working fluid inlet 203, upward flow is induced to promote the rapid detachment of bubbles from the heat pipe surface, preventing bubbles from accumulating and merging at the bottom of the cold-side cavity 201 under the action of surface tension, thus preventing the formation of a gas film that would lead to a deterioration in heat exchange efficiency.

[0057] A working fluid outlet 202 is provided on the shell at the top of the cold side cavity 201, and the vaporized heat pump working fluid leaves through the working fluid outlet 202.

[0058] Preferably, there are multiple working fluid inlets 203, which are evenly distributed on the shell. For example, a liquid distribution pipe can be provided, which surrounds the shell and has multiple branch pipes. Each branch pipe is connected to one or more working fluid inlets 203. The heat pump working fluid is introduced into the liquid distribution pipe and enters the working fluid inlet 203 through the branch pipe, thereby being evenly distributed into the cold side cavity 201.

[0059] The shell is provided with a waste heat carrier inlet 102 and a waste heat carrier outlet 103 that are connected to the hot side cavity 101. The waste heat carrier enters the hot side cavity 101 from the waste heat carrier inlet 102 and is finally discharged from the waste heat carrier outlet 103.

[0060] A ash discharge port 104 is also provided on the shell located at the bottom of the hot side cavity 101. When the waste heat carrier carries solid particles such as dust, such solid particles can be discharged from the ash discharge port 104.

[0061] The present invention and its embodiments have been described above illustratively. This description is not restrictive, and the figures shown are only one embodiment of the present invention; the actual structure is not limited thereto. Therefore, if those skilled in the art are inspired by this description and design similar structures and embodiments without departing from the inventive spirit of the present invention, such designs should fall within the protection scope of the present invention.

Claims

1. A high-flux heat pipe evaporator for heat pumps, characterized in that, include: The housing has a hot-side perforated plate (105) and a cold-side perforated plate (106) inside, which divide the inner cavity of the housing into a hot-side cavity (101) and a cold-side cavity (201). Multiple heat pipes pass through through holes provided in the hot-side perforated plate (105) and the cold-side perforated plate (106), so that the hot-side cavity (101) and the cold-side cavity (201) are not connected to each other; The heat pipe includes a hot-side tube body (301) and a cold-side tube body (302); in: The hot-side tube (301) passes through the hot-side orifice plate (105), and the cold-side tube (302) passes through the cold-side orifice plate (106); The adjacent ends of the hot-side tube (301) and the cold-side tube (302) are detachably connected, so that the hot-side tube (301) and the cold-side tube (302) are connected.

2. The high-flux heat pipe evaporator for heat pumps according to claim 1, characterized in that: A porous layer (305) is provided on the outer surface of the cold side tube (302).

3. The high-flux heat pipe evaporator for heat pumps according to claim 2, characterized in that: The thickness of the porous layer (305) is 0.15 mm to 0.25 mm.

4. The high-flux heat pipe evaporator for heat pumps according to claim 1, characterized in that: The outer surface of the hot-side tube (301) is provided with heat-conducting fins.

5. The high-flux heat pipe evaporator for heat pumps according to claim 1, characterized in that: The hot-side tube body (301) is interference-fitted with the hot-side orifice plate (105); The cold-side tube (302) is fixedly connected to the cold-side orifice plate (106).

6. The high-flux heat pipe evaporator for heat pumps according to claim 1 or 2, characterized in that: For the hot-side tube body (301) and the cold-side tube body (302), one tube body end is provided with an external thread and the other tube body end is provided with an internal thread; The hot-side tube (301) and the cold-side tube (302) are connected by threads, and a sealing ring (303) is provided at the connection.

7. The high-flux heat pipe evaporator for heat pumps according to claim 6, characterized in that: The hot-side tube (301) and the cold-side tube (302) form an internal space; The cold side pipe body (302) is provided with an air extraction port (304), which can draw the space inside the pipe into a negative pressure through the air extraction port (304); and the air extraction port (304) can be sealed.

8. The high-flux heat pipe evaporator for heat pumps according to claim 1, characterized in that: A working fluid inlet (203) is provided on the shell located at the bottom of the cold side cavity (201); A working fluid outlet (202) is provided on the shell located at the top of the cold side cavity (201).

9. The high-flux heat pipe evaporator for heat pumps according to claim 8, characterized in that: The working fluid inlet has multiple inlets, which are evenly distributed on the shell.

10. The high-flux heat pipe evaporator for heat pumps according to claim 1, characterized in that: The housing is provided with a waste heat carrier inlet (102) and a waste heat carrier outlet (103) that communicate with the hot side cavity (101); A ash discharge port (104) is also provided on the shell at the bottom of the hot side cavity (101).

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