WO2008018429A1

WO2008018429A1 - Evaporator

Info

Publication number: WO2008018429A1
Application number: PCT/JP2007/065399
Authority: WO
Inventors: Takahiro Agata
Original assignee: Takahiro Agata
Priority date: 2006-08-10
Filing date: 2007-08-07
Publication date: 2008-02-14
Also published as: JPWO2008018429A1; JP4917048B2

Abstract

It is possible to provide an evaporator which does not cause an intermittent, local dry out or interruption of supply of a working fluid to a heat conductive plane. Accordingly, even if the heat flux increases, the size of the evaporator need not be increased. The evaporator uses water as a working fluid. Even if the heat source temperature is below 100 degrees C, the evaporator can effectively use a slight temperature difference from the heat source. Two heat conducting plates (2) arranged to oppose to each other sandwich an expand metal (3) as a nucleus forming member forming a boiling nucleus between the heat conducting plates (2).

Description

Technical field

The present invention relates to an evaporator, and more particularly to an evaporator that can generate a vapor of the working fluid by heating the working fluid with a heat source and can be used in various situations.

Background art

In recent years, an evaporator has been used in various scenes. For example, Patent Document 1 below shows an evaporator used in a thermoelectric generator. Patent Document 2 below shows an evaporator for cooling a stack of a solid polymer electrolyte fuel cell, and Patent Document 3 below describes evaporation as a component of a heat exchange device. A vessel is shown. Furthermore, the following Patent Document 4 shows an evaporator as a stacked heat exchanger, and the following Patent Document 5 is used as a heat sink for a power semiconductor element by being incorporated in a stack assembly of a semiconductor device. An evaporator as a boiling cooling body is shown. As the steam generation mode of the evaporator, nucleate boiling, which has the potential to greatly increase the heat transfer rate from the heat transfer surface to the working fluid, has been conventionally used (Patent Documents 1 to 5). If nucleate boiling can be used, it depends greatly on the state of occurrence of nucleate boiling, but it is possible to achieve a heat transfer coefficient that is approximately 10 to 100 times that of forced convection water flow. Yes.

[0003] In nucleate boiling from the heat transfer surface, the bubble nuclei formed on the basis of minute scratches and cavities on the heat transfer surface become the foaming points (boiling nuclei), from which the growth and separation of vapor bubbles occur. It happens by being repeated. In addition, if the heat transfer surface is rough, the size of bubble nuclei will increase, and nucleate boiling will start and be sustained even if the degree of superheat, which is the difference between the surface temperature of the heat transfer surface and the saturation temperature of the working fluid, is small. . In the evaporators described in Patent Documents 3 to 5, using this characteristic, the heat transfer surface is lined with a sintered metal, the protrusion is formed, the minute recess is formed, the reinforcing rib It has been shown that the bottom shape of the tube is made V-shaped to facilitate nucleate boiling.

However, a vertical plane such as a machine or device is directly used as a heat transfer surface to transfer heat. In cases where it is difficult to roughen the surface of the heat transfer surface, such as when the working fluid is boiled by immersing the hot surface in the working fluid and heat exchange is performed (Patent Document 2), a smooth heat transfer surface is required. It will cause nucleate boiling, and the superheating degree at the boiling start point will be as high as 10 ° C. For this reason, the evaporation temperature of the working fluid is 10 ° C or more lower than the heat source temperature.If the temperature of the heat source to be used is 100 ° C or less, the heat utilization efficiency and the heat dissipation efficiency will be reduced! there were.

[0005] On the other hand, in the evaporators described in Patent Documents 3 to 5, the sintered metal is lined on the heat transfer surface, the protrusions are formed, the fine recesses are formed, and the bottom shape of the reinforcing rib is V-shaped. There was a problem that the manufacturing process required considerable labor and the production cost was high.

[0006] Further, even in the above-described nucleate boiling! /, Even in the case of a misaligned evaporator, the grown vapor bubbles quickly detach from the heat transfer surface due to the natural convection and buoyancy of the working fluid. There was a problem that it was necessary to secure sufficient space for smooth operation, and the evaporator had to be enlarged with increasing heat flux.

[0007] Further, in nucleate boiling in pool boiling, the temperature of the heat transfer surface rises, and when the degree of superheat reaches a certain value, the bubble bubble grows and begins to grow as a large bubble nucleation point. As the degree of superheat increases, small bubble nuclei also become foaming points and the number of foaming points increases, and from the foaming point, a series of vapor bubbles starts up. This weak nucleate boiling region is called an isolated bubble region.

[0008] When the degree of superheat is further increased, the foaming point density on the heat transfer surface increases, and many bubbles that are generated and floated are also crowded. Eventually, steam bubbles that continue from the foaming point are connected to the front and back, creating what appears to be a thin open-cell column, or the bubbles that are floating are united with each other at a distance from the heat transfer surface.

[0009] When the temperature of the heat transfer surface rises further, the boiling appears to be different from the past, and a considerably large vapor mass covers the heat transfer surface and repeats growth and separation. A thin liquid layer sandwiched between the heat transfer surface and the vapor block receives heat from the heat transfer surface and supplies steam to the vapor block while reducing the amount of liquid. In order for boiling to continue on the heat transfer surface forever, the thin liquid layer is replenished with liquid at the moment when the vapor mass breaks off, and the amount of evaporation corresponding to the heat flux from the heat transfer surface You need to be balanced and have the power to do it. This strong, nucleate boiling area A very large heat transfer coefficient is realized.

[0010] This interference region is extremely excellent in heat transfer performance! / When the force and heat flux exceed a certain limit value, the balance is lost, the heat transfer surface is covered with superheated steam, and the heat transfer performance is abrupt. The critical heat flux phenomenon appears.

[0011] In practical evaporators, the volume and shape of the evaporator are limited due to the spatial restrictions of the installation location, and the critical heat flux phenomenon may occur before nucleate boiling reaches the interference region. In other words, in nucleate boiling on a heat-transfer surface that has been roughened, the heat flux increases rapidly with a slight increase in superheat, so the number of foaming points increases rapidly, generating steam bubbles. The withdrawal cycle is also very fast. When the steam bubbles increase, natural convection is accelerated and irregular flows such as local downflows may occur, and the steam bubbles that have been blocked from separating coalesce to form a large steam mass locally. The heat transfer surface may be covered. As a result, supply of the working fluid to the heat transfer surface may be delayed, causing intermittent and local dryout, resulting in a decrease or fluctuation in heat flux.

[0012] It should be noted that due to nucleate boiling in the above-mentioned interference region! /, Close to the critical heat flux! /, A liquid is artificially formed on the heat transfer surface in a state using, for example, a thin tube like an injection needle. It is known as an experimental fact that nucleate boiling can be easily increased to a higher heat flux if replenished periodically.

[0013] If the heat source temperature is 100 ° C or lower, it is desirable to use water as a working fluid from the viewpoints of cost, safety, ease of maintenance, and the like. However, when the heat source temperature is low, that is, in the case of low-pressure boiling where the saturation pressure of the working fluid vapor is very low, the working fluid depth in the evaporator has a problem of suppressing nucleate boiling. For example, if the heat source temperature is 30 ° C, the working fluid is water and boiling at 25 ° C, its saturated vapor pressure is 3168 Pascals (Pa). And when the water depth is 10cm, it will boil at a temperature that makes about 4200Pa saturated vapor pressure by adding about lOOOPa as water pressure. Its temperature is about 30 ° C. In other words, in this example, it means that boiling does not occur where the water depth exceeds 10 cm. Therefore, in heat exchange systems that use only a slight temperature difference (for example, use of hot spring exhaust heat), it is impossible to use conventional evaporators that use nucleate boiling from the viewpoint of water depth. There was a problem. Patent Document 1: Japanese Patent Laid-Open No. 2005-24132

Patent Document 2: JP-A-2005-190725

Patent Document 3: Japanese Patent Laid-Open No. 5-52491

Patent Document 4: Japanese Patent Laid-Open No. 7-127987

Patent Document 5: JP 2000-77586 Koyuki

Disclosure of the invention

[0014] The present invention has been made in view of the above problems, and does not cause intermittent and local dryout, and the supply of the working fluid to the heat transfer surface does not stagnate, so that the heat flux increases. However, even if the evaporator is not required to be large and water is used as the working fluid and the heat source temperature is 100 ° C or less, only a slight temperature difference from the heat source can be used effectively. The goal is to provide an evaporator that will be revolutionary eco-technologies!

[0015] In order to achieve the above object, an evaporator (1) according to the present invention has a nucleation member that forms boiling nuclei between two planes arranged opposite to each other. One of these two planes or two planes are sandwiched and constitute a heat transfer surface that transfers heat from the heat source to the working fluid.

[0016] The structure of the nucleation member is not particularly limited as long as it can form boiling nuclei at an appropriate density by contacting the flat surface at an appropriate ratio. For example, an expanded metal is sufficient. There is no particular limitation on the material that is desired to have space.

[0017] According to the evaporator (1), when the heat flux is extremely small, a part of bubble nuclei formed at the contact point between the nucleation member and the plane in the plane that transmits heat from a heat source. Weak nucleate boiling occurs at the bubble point, and the separated vapor bubble rises as if it were sewn between the nucleation members.

[0018] When the heat flux is slightly increased, the foaming point density on the heat transfer surface is increased, and a continuous rise of vapor bubbles occurs.

[0019] When the heat flux is further increased, a space surrounded by steam is generated in the upper layer portion. However, in this space, there is an ascending vapor flow inside the vapor mass that is a combination of vapor bubbles, and it is ejected from the gas-liquid interface. When the heat flux is further increased, most of the plane is filled with steam except for the lower layer. However, even though the uppermost layer is vigorously disturbed by the vapor flow, the liquid exists and an intermittent upward flow of gas-liquid mixing occurs in a part of the plane.

[0020] Even in the plane filled with steam, there is a liquid flow that flows down through the nucleation member, and nucleate boiling using the contact point between the nucleation member and the plane as a foaming point is maintained. There, the nucleate boiling force is generated in the form of bursting of small vapor bubbles that do not grow large. In addition, a part of the liquid flow that flows down through the nucleation member flows to the flat surface and forms a thin liquid film covering the flat surface, and the heat transmitted from the flat surface is a liquid portion of the thin liquid film. Is transferred to the gas-liquid interface in contact with the vapor flow through heat conduction, where the vapor with saturated vapor pressure and temperature is continuously evaporated.

[0021] According to the evaporator (1), from the plane to the working fluid, the nucleation member that forms the boiling nuclei is sandwiched between the two planes arranged opposite to each other. Nucleate boiling, which can maximize the heat transfer coefficient, can be generated and maintained very reliably and efficiently. However, it takes time and effort to increase the cost, such as lining sintered metal on the heat transfer surface, forming protrusions, forming minute recesses, and making the bottom shape of the reinforcing rib V-shaped. It is possible to provide a small, revolutionary, high-performance evaporator at a low cost that does not require a manufacturing process.

[0022] The thickness of the nucleation member may be 2 mm or less, whereas the evaporation part depth may be several hundred mm or more, which makes it extremely thin and has a wide area. Can provide you with an evaporator. In conventional evaporators, the shape of such a thin evaporation section could not eliminate the gravitational action (buoyancy) that lifts and raises the vapor bubbles from the foaming point, and the critical heat flux could not be very low.

[0023] In the case of an isolated bubble region of nucleate boiling in a conventional evaporator, the amount of heat transferred from the heat transfer surface is relatively small, and a considerable amount of heat is used to generate steam bubbles on the heat transfer surface. Therefore, the superheated liquid layer that is higher than the saturation temperature in contact with the heat transfer surface is spent, and the convection heat transfer of this superheated liquid layer force causes the liquid in the evaporator to be superheated slightly above the saturation temperature as a whole. The growth of vapor bubbles during levitation and evaporation from the free liquid surface above the liquid occurred.

On the other hand, in the evaporator according to the present invention, the heat transfer is performed at a stage of relatively small heat flux. The surface of the heat transfer surface can be covered with a steam flow, and the heat transferred from the heat transfer surface is transferred to the gas-liquid interface in contact with the steam flow through heat conduction, where the saturated vapor pressure 'temperature It becomes an efficient form to continuously evaporate the steam. This efficient evaporation form not involving convection heat transfer is the same as the vapor mass generation seen in the interference region of nucleate boiling. Select a working fluid that has a high saturation pressure and does not cause low-pressure boiling.

[0025] If the heat flux is not so large that a part of the heat transfer plane is intermittently covered with the steam flow, the two planes sandwiching the nucleation member may be inclined rather than substantially vertical. .

[0026] Further, the evaporator (2) according to the present invention is characterized in that the two planes are arranged substantially vertically.

According to the evaporator (2), the installation area of the evaporator can be minimized.

[0027] Further, the evaporator (3) according to the present invention is characterized in that the two planes are arranged to be inclined with respect to a vertical plane.

[0028] According to the evaporator (3), the evaporator can be stably mounted on the roof or the like according to the inclination angle of the mounting surface such as the roof.

[0029] In addition, the evaporator (4) according to the present invention is exposed above the gas-liquid separation interface of the nucleation member working fluid in any of the evaporators (1) to (3). The special feature is that it is structured as follows.

[0030] According to the evaporator (4), even if the vapor ejected from the heat transfer surface violently boiles the gas-liquid separation interface, the upper end of the nucleation member is completely encased in the vapor and causes dryout. The working fluid can always be maintained in a state where it flows down the nucleation member and heat transfer efficiency can be improved.

[0031] Further, the evaporator (5) according to the present invention is characterized in that in any of the evaporators (1) to (4), the nucleation member is formed of an expanded metal! As! /

[0032] Expanded metal is widely used, and various types can be obtained at low cost. Therefore, according to the evaporator (5), it is possible to form the nucleation member at a low cost, and to optimize the force according to the situation, and to provide a high-performance evaporator at a low cost. It will be defeated with force S.

[0033] Further, in the evaporator (6) according to the present invention, in any one of the evaporators (1) to (5), a gas-liquid separation header is continuously provided above the two planes. It is a feature.

According to the evaporator (6), the plane is covered with the vapor flow, so that the working liquid filling the evaporator is pushed out and flows out from the evaporator to the condenser in a gas-liquid mixed flow state. Gas-liquid separation is performed to prevent the occurrence of dryout, and the working fluid can always be stably supplied between the nucleation member and the flat surface, and more reliably preventing the occurrence of dryout and increasing the heat transfer efficiency. be able to.

[0034] Further, in the evaporator (7) according to the present invention, in the evaporator (6), a liquid reservoir is connected to a lower portion of the two planes, and the liquid reservoir and the gas-liquid separation header are connected to each other. The conveying means connected via the connecting means and sending the working fluid accumulated in the liquid reservoir to the gas-liquid separation header is interposed in the connecting means.

[0035] According to the evaporator (7), when the working fluid flows, when the saturated vapor pressure is in a low pressure region, the bubble nuclei formed at the contact point between the nucleation member and the two planes become the working fluid. An amount of working fluid is circulated between the gas-liquid separation header and the liquid reservoir so as not to be immersed and capable of maintaining a liquid flow flowing down the nucleation member. Regardless of the vertical distance of the heat transfer surface, it is possible to cause nucleate boiling with the entire surface of the heat transfer surface covered with steam flow.

[0036] In the evaporator (8) according to the present invention, a nucleation member is sandwiched between two heat transfer plates to constitute one unit,

A through hole is formed in the opposite location of the upper part of the two heat transfer plates,

These units are stacked horizontally via two upper and lower separators,

A through hole is formed at a location facing the through hole of the upper separator,

A gas-liquid separation header is constituted by the upper separator and the through holes of the two heat transfer plates, while a space formed by two adjacent heat transfer plates and the upper and lower separators is a heat source flow portion. As a feature, it becomes!

According to the evaporator (8), an extremely thin and extremely high performance evaporator can be realized. Also, since the heat source flow part is surrounded by a flat surface, Teflon (registered trademark) Coating such as processing can be easily performed, and it can be applied regardless of the type of heat source, and it can be made suitable for exhaust heat use of hot springs, which are usually difficult to use due to scale problems.

[0037] Further, an evaporator as a cooling device for a solid polymer electrolyte fuel cell stack and an evaporation as a boiling type cooling body used as a heat sink for a power semiconductor element incorporated in a stack assembly of a semiconductor device. If the evaporator (8) is used in a vacuum vessel, etc., it is possible to provide a high performance, excellent workability, inexpensive, thin, and space-saving evaporator.

[0038] In the evaporator (9) according to the present invention, a nucleation member is sandwiched between two heat transfer plates to constitute one unit,

Through-holes are formed at opposite locations of the upper and lower portions of the two heat transfer plates, and these units are stacked horizontally via two upper and lower separators,

A through-hole is formed at a location facing the through-hole of the upper and lower separators, and a gas-liquid separation header and a liquid reservoir are configured by the through-holes of the upper and lower separators and the two heat transfer plates,

The liquid reservoir and the gas-liquid separation header are connected via a connecting means,

While the conveying means for sending the working fluid accumulated in the liquid reservoir to the gas-liquid separation header is interposed in the connecting means,

Specially, the space formed by the two adjacent heat transfer plates and the upper and lower separators serves as a flow path for the heat source.

[0039] According to the evaporator (9), even when the saturated vapor pressure is in a low pressure region during operation of the working fluid, the entire surface of the heat transfer plate is covered regardless of the vertical distance of the heat transfer plate. Thus, it is possible to cause nucleate boiling at substantially the same saturation temperature to occur at the foaming point formed at the contact point between the heat transfer plate and the nucleation member. Therefore, it is possible to provide a high-performance evaporator that makes the best use of nucleate boiling even with a heat exchange system that uses only a small temperature difference.

Brief Description of Drawings

FIG. 1 is an exploded perspective view showing an evaporator according to a first embodiment of the present invention.

FIG. 2 is an assembled perspective view showing the evaporator according to the first embodiment. FIG. 3 is an enlarged cross-sectional view taken along line m-πι in FIG. 2 showing the evaporator according to the first embodiment.

FIG. 4 is an exploded perspective view showing an evaporator according to a second embodiment of the present invention.

FIG. 5 is an assembled perspective view showing an evaporator according to a second embodiment.

FIG. 6 is an enlarged sectional view taken along line VI-VI in FIG. 5 showing an evaporator according to a second embodiment.

FIG. 7 is an assembled perspective view showing an evaporator according to a third embodiment of the present invention.

FIG. 8 is a cross-sectional view taken along the line vm-vm in FIG. 7, showing an evaporator according to a third embodiment.

FIG. 9 is a partially exploded perspective view showing an evaporator according to a fourth embodiment of the present invention.

FIG. 10 is an exploded perspective view showing an evaporation plate unit according to a fourth embodiment.

FIG. 11 is a cross-sectional view of the ΧΙ-Xl spring assembly in FIG.

FIG. 12 is a partially exploded perspective view showing an evaporator according to a fifth embodiment of the present invention.

FIG. 13 is an exploded perspective view showing an evaporation plate unit according to a fifth embodiment.

FIG. 14 is a sectional view taken along line XIV-XIV in FIG.

BEST MODE FOR CARRYING OUT THE INVENTION

FIG. 1 is an exploded perspective view showing an evaporator according to a first embodiment of the present invention, FIG. 2 is an assembled perspective view, and FIG. 3 is an enlarged sectional view taken along the line in FIG. In the figure, 1 indicates an evaporator. Evaporator 1 includes two rectangular metal heat transfer plates 2, and stainless steel expanded metal 3 4 as a nucleation member cut into a rectangular shape. It includes a stainless steel frame 4 with the upper side removed, and a heat transfer plate 2, expanded metal 3, and a stainless steel gas-liquid separation header 5 connected to the top of the frame 4. It is made.

[0042] The gas-liquid separation header 5 is connected to a metal condensate pipe LP and a metal steam pipe VP. The working fluid liquefied by a condenser (not shown) is condensed into the condensate pipe LP. Flows into the gas-liquid separation header 5 and is stored in the gas-liquid separation header 5 to form a gas-liquid separation liquid level Ld and flows between the two heat transfer plates 2 to be introduced into the expanded metal 3. As a result, it flows down between the expanded metal 3 and the two heat transfer plates 2. During this flow, the working fluid receives heat from a heat source (not shown) via the heat transfer surface 2a of the heat transfer plate 2, and evaporates to the boiling point. I will do it. The heat source side plane of the heat transfer plate 2 is processed with Teflon (registered trademark), and even if the heat source has a scale problem such as hot spring water, it is configured to be maintenance-free.

[0043] According to the evaporator 1 according to the first embodiment, even when the heat flux is extremely small, the expanded metal 3 and the heat transfer surface are formed on the upper layer portion of the heat transfer plate 2 in contact with the heat source (not shown). Contact with 2a Weak nucleate boiling occurred at BP as the foaming point, and the separated vapor bubbles rose as if they were sewed between the expanded metals 3.

[0044] When the heat flux was slightly increased, the foaming point density on the heat transfer surface increased, and a continuous increase in vapor bubbles occurred.

[0045] When the heat flux was further increased, a space surrounded by steam was generated in the upper layer portion. However, in this space, there is an ascending vapor flow inside the vapor mass that is a combination of vapor bubbles, and it is ejected from the gas-liquid interface.

When the heat flux further increases, most of the heat transfer surface 2a of the heat transfer plate 2 is filled with steam except for the lower layer. However, although the uppermost layer was severely disturbed by the vapor flow, liquid was present, and an intermittent upward flow of gas-liquid mixture occurred in a part of the heat transfer surface 2a.

[0046] Even on the heat transfer surface 2a filled with steam, there was a dish flowing down through the expanded metal 3, and nucleate boiling with the contact point between the expanded metal 3 and the heat transfer surface 2a maintained as a foaming point. There, nucleate boiling occurred in the form of rupture of small vapor bubbles, one after the other, where the vapor bubbles do not grow large. In addition, a part of the liquid flow that flows down through the expanded metal 3 flows to the heat transfer surface 2a and forms a thin liquid film covering the heat transfer surface 2a, and the heat transferred from the heat transfer surface 2a is the thin liquid. The liquid part of the membrane is transferred by heat conduction to the gas-liquid interface in contact with the vapor stream, where the vapor with saturated vapor pressure and temperature is continuously evaporated.

[0047] According to the evaporator 1, the heat transfer plate 2 has a simple configuration in which the expanded metal 3 that forms boiling nuclei is sandwiched between the heat transfer plates 2 that are arranged substantially opposite to each other. It was possible to generate nucleate boiling with extremely high heat transfer rate from the working fluid to the working fluid very reliably and efficiently. In addition, the cost increases such as lining the sintered metal on the heat transfer surface 2a, forming protrusions, forming minute recesses, and making the bottom shape of the reinforcing rib V-shaped. It was possible to provide a low-cost, extremely high-performance evaporator that did not require time-consuming manufacturing processes.

[0048] Further, since the expanded metal 3 is configured to be exposed above the gas-liquid separation interface Ld of the working fluid, the steam ejected from the heat transfer plate 2 violently boils the gas-liquid separation interface Ld. Even if it is erected, the working fluid can be maintained in a state where the upper end of the expanded metal 3 is completely encased in steam and does not dry out. did it.

[0049] In addition, the expanded metal 3 is widely used, and it is possible to obtain various types at low cost. Therefore, it is possible to form the nucleation member at a low cost and with an optimum force according to the situation, and to provide a high-performance evaporator at a low cost.

[0050] Since the gas-liquid separation header 5 is connected to the upper part of the heat transfer plate 2, the working fluid can always be stably supplied between the expanded metal 3 and the heat transfer plate 2. Therefore, it is possible to reliably prevent the occurrence of dryout and increase the heat transfer efficiency.

It should be noted that, as in the present embodiment, when the evaporator 1 has a flat plate shape, the expanded metal 3 cannot be sandwiched between the heat transfer plates 2 if the internal pressure becomes larger than the external pressure. Therefore, it is necessary to select a working fluid having an appropriate saturated vapor pressure in which the internal pressure is smaller than the external pressure in accordance with the heat source temperature.

4 to 6 show an evaporator 1A according to the second embodiment of the present invention. FIG. 4 is an exploded perspective view, FIG. 5 is an assembled perspective view, and FIG. An enlarged cross-sectional view of line VI is shown.

[0053] The evaporator 1A force according to the second embodiment shown in FIGS. 4 to 6 is different from the evaporator 1 according to the first embodiment shown in FIGS. The structure of the header 5A and the connection form between the gas-liquid separation header 5A and the heat transfer plate 2A. Since the other points are the same as those of the evaporator according to the first embodiment, detailed description thereof is omitted here.

As shown in FIGS. 4 to 6, in the evaporator 1A according to the second embodiment, the shape of the gas-liquid separation header 5A is the same as that of the gas-liquid separation header 5 of the first embodiment. In addition, it has a rectangular parallelepiped shape rather than a cylindrical shape, and is designed to reduce costs based on ease of manufacture. Gas-liquid separation header 5A is attached to the upper side of heat transfer plate 2A. The supply ports 5b and 2b for supplying the working fluid stored in the gas-liquid separation header 5A between the heat transfer plates 2 and 2A are formed in the gas-liquid separation header 5A and the heat transfer plate 2A.

[0055] According to the evaporator 1A according to the second embodiment, the force S can provide a cheaper and higher performance evaporator.

7 and 8 show an evaporator according to a third embodiment of the present invention. FIG. 7 is an assembled perspective view, and FIG. 8 is a sectional view taken along the line vm-vm in FIG. Show.

The difference between the evaporator 1B according to the third embodiment shown in FIG. 7 and FIG. 8 and the evaporator 1 according to the first embodiment shown in FIG. 1 to FIG. A liquid reservoir header 6 is connected to the lower part of the hot plates 2 and 2, and the liquid reservoir header 6 and the gas-liquid separation header 5 are connected via a pipe 7, and the working fluid accumulated in the liquid reservoir header 6 is gas-liquid. A pump 8 as a conveying means to be sent to the separation header 5 is interposed near the liquid reservoir header 6 of the pipe 7. Since the other points are the same as those of the evaporator 1 according to the first embodiment, a detailed description thereof is omitted here.

[0058] According to the evaporator 1B according to the third embodiment, even when the saturated vapor pressure is in the low pressure region during operation of the working fluid, regardless of the vertical distance between the heat transfer plates 2 and 2, Over the entire surface of the heat transfer plates 2 and 2, nucleate boiling at substantially the same saturation temperature can be caused at the foaming points formed at the contact points between the heat transfer plates 2 and 2 and the expanded metal 3. Therefore, even with a heat exchange system that uses only a small temperature difference, it is possible to provide a high-performance evaporator that makes the most of nucleate boiling.

[0059] As an application of the evaporator according to the present embodiment, a solar heat collector using sunlight as a heat source may be incorporated as a heat collection medium heater (evaporator). In this application example, a solar heat collector is installed on the south side wall of the building, and in winter heat collection at low solar altitude, a low boiling point working fluid is used, so there is a concern about freezing even in sub-freezing environments. It can collect heat as a heat source of a heat pump for heating.

FIGS. 9 to 11 show a stack type evaporator according to a fourth embodiment of the present invention, FIG. 9 is a partially exploded perspective view, and FIG. 10 is an exploded perspective view showing an evaporation plate unit. FIG. 11 shows a sectional view taken along line X-XI in FIG.

[0061] In the evaporator 1C according to the fourth embodiment shown in Figs. 9 to 11, two heat transfer plates 2B, Expanded metal 3 as a nucleation member is sandwiched between 2B to constitute one unit of evaporation plate 20. Through-holes 2c and 2c constituting the gas-liquid separation header 5B are formed at opposite positions on the top of the two heat transfer plates 2B and 2B. These evaporation plates 20 are connected via two upper and lower separators 9 and 10, respectively. They are stacked horizontally.

[0062] A through hole 9a is formed at a position facing the through hole 2c of the upper separator 9, and a gas-liquid separation header 5B is configured by the upper separator 9 and the through holes 2c and 2c of the two heat transfer plates 2B and 2B. On the other hand, the space formed by the two adjacent heat transfer plates 2B and 2B and the upper and lower separators 9 and 10 serves as a heat source flow passage 15.

[0063] The evaporation plate 20 includes two heat transfer plates 2B and 2B each having a rectangular shape, an expanded metal 3 cut into a rectangular shape, and a frame 4B having four sides. A large number of these evaporation plates 20 are stacked horizontally between the end plates 11 and 11 via two upper and lower separators 9 and 10, supported by a large number of tie rods 12, and fastened and fixed by bolts 13. ing.

[0064] A condensate pipe LP and a steam pipe VP are connected to the gas-liquid separation header 5B via an end plate 11, and the working fluid liquefied by a condenser (not shown) is connected to the condensate pipe LP. Flows into the gas-liquid separation header 5B and is stored in the gas-liquid separation header 5B, forms the gas-liquid separation liquid level Ld, flows between the two heat transfer plates 2B, 2B, and is led to the expanded metal 3. As a result, it flows down between the expanded metal 3 and the two heat transfer plates 2B, 2B. During this flow, the working fluid receives heat from the heat source (not shown) via the heat transfer surface 2a of the heat transfer plates 2B and 2B, and evaporates to the boiling point.

[0065] According to the evaporator 1C according to the fourth embodiment, an extremely thin and extremely high performance evaporator can be realized. In addition, since the heat source flow portion 15 is formed by being surrounded by a flat surface, coating such as Teflon (registered trademark) processing can be easily performed, and it can be applied regardless of the type of heat source. The power S is suitable for the use of exhaust heat from hot springs that are difficult to use.

[0066] Further, an evaporator as a cooling device for a stack of a solid polymer electrolyte fuel cell and an evaporation as a boiling type cooling body used as a heat sink for a power semiconductor element incorporated in a stack assembly of a semiconductor device. Extremely thin and extremely high performance evaporator Can be realized. In addition, since the flow path of the heat source is surrounded by a flat surface, coating such as Teflon (registered trademark) processing can be performed easily, and it can be applied regardless of the type of heat source. Power that is suitable for the use of exhaust heat from hot springs that are difficult to use.

[0067] In addition, an evaporator as a cooling device for a solid polymer electrolyte fuel cell stack, and an evaporation as a boiling type cooling device used as a heat sink for a power semiconductor element incorporated in a stack assembly of a semiconductor device. If the evaporator 1C is applied to an evaporator, etc., it is possible to provide an evaporator that has high performance, excellent workability, is inexpensive, thin, and does not require installation space.

FIGS. 12 to 14 show a stack type evaporator according to a fifth embodiment of the present invention, FIG. 12 is a partially exploded perspective view, and FIG. 13 is an exploded view showing an evaporation plate unit. A perspective view, FIG. 14 shows a sectional view taken along line XIV-XIV in FIG.

In the evaporator 1D according to the fifth embodiment shown in FIGS. 12 to 14, the expanded metal 3 as a nucleation member is sandwiched between the two heat transfer plates 2C, 2C, and the evaporation plate One unit of 20A is configured. Through holes 2c, 2c, 2d, and 2d constituting the gas-liquid separation header 5B and the liquid reservoir header 6B are formed at the opposite locations of the upper and lower portions of the two heat transfer plates 2C and 2C. They are stacked in the horizontal direction via two separators 9 and 10A.

[0070] A through hole 9a is formed at a position facing the through hole 2c of the upper separator 9, and gas-liquid separation is performed by the through hole 9a of the upper separator 9 and the through holes 2c and 2c of the two heat transfer plates 2C and 2C. While the header 5B is formed, a through hole 10d is formed at a position facing the through hole 2d of the lower separator 10A, and the through hole 10 (one and two heat transfer plates 2 (:, 2) of the lower separator 10 8 is formed. (: Through-hole 2 (1, 2 (1) The reservoir 6B is formed, and the space surrounded by the two adjacent heat transfer plates 2C, 2C and the upper and lower separators 9, 10A is the heat source. It is a convection section 15.

[0071] The evaporation plate 20A includes two rectangular heat transfer plates 2C and 2C, an expanded metal 3 cut into a rectangular shape, and a frame 4B composed of four sides. A large number of these evaporation plates 20A are stacked in a horizontal direction between the end plates 11 and 11 via two separators 9 and 10A, and are supported by a large number of tie rods 12 and bolts. Tightened and fixed by 13

[0072] A condensate pipe LP and a steam pipe VP are connected to the gas-liquid separation header 5B via an end plate 11, and the working fluid liquefied by a condenser (not shown) is connected to the condensate pipe LP. Flows into the gas-liquid separation header 5B, and is stored in the gas-liquid separation header 5B, forms the gas-liquid separation liquid level Ld, and flows between the two heat transfer plates 2C and 2C to the expanded methanol 3 It is led down and flows down between the expanded metal 3 and the two heat transfer plates 2C and 2C. During this flow, the working fluid receives heat from a heat source (not shown) via the heat transfer surface 2a of the heat transfer plates 2C and 2C, and evaporates to the boiling point.

[0073] Further, the liquid reservoir header 6B and the gas-liquid separation header 5B are connected via the pipe 7, and a pump as a conveying means for sending the working fluid accumulated in the liquid reservoir header 6B to the gas-liquid separation header 5B. 8 is installed near the reservoir header 6B of the pipe 7. Since the other points are the same as those of the evaporator 1C according to the fourth embodiment, detailed description thereof is omitted here.

[0074] According to the evaporator 1D according to the fifth embodiment, in addition to the effect obtained by the evaporator 1C according to the fourth embodiment, the saturated vapor pressure is in the low pressure region when the working fluid is operated. However, regardless of the vertical distance between the heat transfer plates 2C and 2C, the nucleate boiling at substantially the same saturation temperature occurs over the entire surface of the heat transfer plates 2C and 2C, and the heat transfer plates 2C and 2C and the expanded metal 3 It can be caused to occur at the foaming point formed at the contact. Therefore, it is possible to provide a high-performance evaporator that makes the best use of nucleate boiling even with a heat exchange system that uses only a small temperature difference.

[0075] In each of the above embodiments, the case where the heat transfer plate 2 and the like are arranged substantially vertically is shown. However, in another embodiment, the heat transfer plate and the like are inclined with respect to the vertical plane. May be arranged. According to the embodiment, the evaporator can be stably mounted on the roof according to the inclination angle of the mounting surface such as the roof.

Industrial applicability

[0076] The evaporator according to the present invention is, for example, used in a thermoelectric generator, for cooling a stack of solid polymer electrolyte fuel cells, as a component of a heat exchange device, or as a heat sink of a power semiconductor element. As such, it can be used industrially in various situations.

Claims

The scope of the claims

[1] A nucleation member that forms boiling nuclei between these two planes is sandwiched between two planes. One or two planes of these two planes heat the heat from the heat source. An evaporator, characterized in that it constitutes a heat transfer surface that transmits to the working fluid.

2. The evaporator according to claim 1, wherein the two planes are arranged substantially vertically! /.

[3] The evaporator according to [1], wherein the two planes are arranged to be inclined with respect to a vertical plane.

[4] The evaporator according to any one of claims 1 to 3, wherein the nucleation member is configured to be exposed above a gas-liquid separation interface of the working fluid.

[5] The evaporator according to any one of [1] to [4], wherein the nucleation member is formed of an expanded metal.

[6] The evaporator according to any one of [1] to [5], wherein a gas-liquid separation header is continuously provided above the two planes.

[7] A liquid reservoir is connected to the lower part of the two planes, the liquid reservoir and the gas-liquid separation header are connected via a connecting means, and the working fluid accumulated in the liquid reservoir is discharged from the gas reservoir. 7. The evaporator according to claim 6, wherein a conveying means for sending to the liquid separation header is interposed in the connecting means.

[8] A nucleation member is sandwiched between two heat transfer plates to form one unit,

These units are stacked horizontally via two upper and lower separators,

A gas-liquid separation header is constituted by the upper separator and the through holes of the two heat transfer plates, while a space formed by two adjacent heat transfer plates and the upper and lower separators is a heat source flow portion. An evaporator characterized by becoming! /.

[9] A nucleation member is sandwiched between two heat transfer plates to form one unit,

A through hole is formed at a location facing the through hole of the upper and lower separators, A gas-liquid separation header and a liquid reservoir are configured by the upper and lower separators and the through holes of the two heat transfer plates,

An evaporator characterized in that a space formed by two adjacent heat transfer plates and the upper and lower separators serves as a heat source flow path!