Evaporator and cooling system

An evaporator includes: a container; a first supplying unit configured to supply a liquid phase refrigerant to an inside of the container; a second supplying unit configured to supply the liquid phase refrigerant along a surface of the container; a heat absorbing unit configured to be disposed on the inside, and in which the liquid phase refrigerant supplied to the inside by the first supplying unit absorbs heat supplied from an outside of the container; a storage part configured to be disposed on the inside, stores the liquid phase refrigerant absorbing the heat in the heat absorbing unit, and stores the liquid phase refrigerant obtained by cooling and condensing a gaseous phase refrigerant evaporated by heat absorption in the heat absorbing unit by using the liquid phase refrigerant supplied along the surface by the second supplying unit; and a discharging unit configured to discharge the liquid phase refrigerant stored.

CROSS-REFERENCE TO RELATED APPLICATION

This application is based upon and claims the benefit of priority of the prior Japanese Patent Application No. 2018-221701, filed on Nov. 27, 2018, the entire contents of which are incorporated herein by reference.

FIELD

The embodiments discussed herein relate to an evaporator and a cooling system.

BACKGROUND

In relation to a technology of cooling an electronic device that generates heat as the electronic device operates, a cooling device, for example, is known in which an evaporator cooling a semiconductor element, a condenser, and a liquid pump are sequentially coupled to a closed circuit by pipes. Further, a method is proposed which partially radiates the heat of a refrigerant heated into a gas-liquid mixed state within an evaporator by an auxiliary condenser or a radiator installed on the evaporator, thereafter condenses and liquefies the refrigerant by a condenser, and feeds the refrigerant to the evaporator again by a liquid pump.

Examples of the related art include Japanese Laid-open Patent Publication No. 2006-12875.

SUMMARY

According to an aspect of the embodiment, an evaporator includes: a container; a first supplying unit configured to supply a liquid phase refrigerant to an inside of the container; a second supplying unit configured to supply the liquid phase refrigerant along a surface of the container; a heat absorbing unit configured to be disposed on the inside, and in which the liquid phase refrigerant supplied to the inside by the first supplying unit absorbs heat supplied from an outside of the container; a storage part configured to be disposed on the inside, stores the liquid phase refrigerant absorbing the heat in the heat absorbing unit, and stores the liquid phase refrigerant obtained by cooling and condensing a gaseous phase refrigerant evaporated by heat absorption in the heat absorbing unit by using the liquid phase refrigerant supplied along the surface by the second supplying unit; and a discharging unit configured to discharge the liquid phase refrigerant stored in the storage part.

DESCRIPTION OF EMBODIMENTS

In a cooling system in which a liquid phase refrigerant is filled in a decompressed state into a closed circuit formed by coupling an evaporator, a radiator, and a pump, and cooling is performed by utilizing a vaporization phenomenon (may be referred to as “vaporizing phenomenon”, “boiling phenomenon”, “evaporating phenomenon”, “evaporation phenomenon”, and the like) of the liquid phase refrigerant heated in the evaporator, the cooling capacity of the evaporator is enhanced when a condition (quantity of the refrigerant, internal pressure, or the like) is used under which vaporizing (may be referred to as “vaporization”, “evaporation”, “evaporating”, “boiling”, and the like) occurs easily in the evaporator.

However, when a gaseous phase refrigerant discharged from the evaporator due to vaporizing is increased, the gaseous phase refrigerant present within the closed circuit of the cooling system is increased, the gaseous phase refrigerant is easily taken into the pump, and there is thus a fear that stable refrigerant circulation may not be performed by the pump.

In one aspect, it is an object of the embodiments discussed herein to realize a high cooling capacity while suppressing discharging of the gaseous phase refrigerant from the evaporator.

An example of the cooling system will first be described.

FIGS. 1A, 1B, and 1Care diagrams of assistance in explaining an example of the cooling system.FIG. 1Aschematically illustrates an example of the cooling system.FIG. 1Bschematically illustrates an example of a state during operation of the cooling system.FIG. 1Cschematically illustrates an example of a problem occurring during the operation of the cooling system.

As illustrated inFIG. 1A, the cooling system1includes an evaporator2, a radiator3, and a pump4. The evaporator2and the radiator3are coupled to each other by a pipe5. The radiator3and the pump4are coupled to each other by a pipe6. The pump4and the evaporator2are coupled to each other by a pipe7. The evaporator2, the radiator3and the pump4as well as the pipe5, the pipe6, and the pipe7form a closed circuit of the cooling system1. A liquid phase refrigerant8is filled in a decompressed state into the closed circuit of such a cooling system1.FIG. 1Aillustrates an example in which there is a decompressed space9within the radiator3before the operation of the cooling system1or in a case where an amount of heat absorbed in the evaporator2is small during operation as described later, for example.

The cooling system1will be further described with reference toFIG. 18. In the cooling system1, utilizing the vaporizing phenomenon (may be referred to as “boiling phenomenon”, “evaporating phenomenon”, “evaporation phenomenon”, “vaporization phenomenon”, and the like) of the internal liquid phase refrigerant8, the evaporator2absorbs heat transmitted from an external heat generating body to be cooled by the cooling system1, for example, heat generated from an electronic device as the electronic device operates. The evaporator2thereby cools the external heat generating body such as the electronic device or the like. The radiator3takes in the liquid phase refrigerant8including a gaseous phase refrigerant8a, the liquid phase refrigerant8being increased in temperature by absorbing heat in the evaporator2, through the pipe5, and radiates the heat to the outside. The radiator3thereby condenses the gaseous phase refrigerant8aand lowers the temperature of the liquid phase refrigerant8. The pump4takes in the liquid phase refrigerant8condensed and lowered in temperature by the radiator3through the pipe6, and feeds the liquid phase refrigerant8to the evaporator2through the pipe7. Using the liquid phase refrigerant8fed from the pump4through the pipe7, the evaporator2absorbs heat from the external heat generating body such as the electronic device or the like (cools the external heat generating body). The cooling system1is an example of a gas-liquid two-phase flow forced circulation type cooling system that thus utilizes the vaporization phenomenon of the liquid phase refrigerant8. Incidentally, the evaporator2may be referred to as a receiver, a cooler, or the like. In addition, the radiator3may be referred to as a condenser or the like.

In the cooling system1as described above, the cooling capacity of the evaporator2is enhanced when a condition is used under which boiling (may be referred to as “evaporation”, “vaporization”, and the like) of the liquid phase refrigerant8occur easily in the evaporator2, that is, when a condition is used under which the gaseous phase refrigerant8aoccurs easily due to the boiling of the liquid phase refrigerant8.FIG. 1Cillustrates an example of the cooling system1in a case where a condition under which boiling of such a liquid phase refrigerant8occurs easily is used. The more easily the liquid phase refrigerant8boils, the more easily a phase change from the liquid phase refrigerant8to the gaseous phase refrigerant8adue to heat occurs. Therefore, heat absorption from the external heat generating body is promoted, and efficiency of heat transmission to the evaporator2is enhanced. The external heat generating body is thereby cooled efficiently, so that the cooling capacity of the evaporator2is enhanced. In a case where boiling of the liquid phase refrigerant8is made to occur easily in the cooling system1, the filling rate of the liquid phase refrigerant8, internal pressure, and the like within the closed circuit are adjusted.

However, when a condition under which the liquid phase refrigerant8boils easily in the evaporator2is used, and consequently the amount of generation of the gaseous phase refrigerant8ain the evaporator2is increased and the amount of discharge of the gaseous phase refrigerant8afrom the evaporator2is thereby increased, the gaseous phase refrigerant8apresent within the closed circuit of the cooling system1is increased. As a result, the gaseous phase refrigerant8adischarged from the evaporator2and fed to the radiator3is not sufficiently condensed in the radiator3, and the gaseous phase refrigerant8aremaining without being condensed is more likely to be sucked into the pump4. In addition, even when the gaseous phase refrigerant8ais condensed by the radiator3and becomes the liquid phase refrigerant8, reboiling (cavitation) due to decompression on the sucking-in side of the pump4may occur depending on a balance with the flow rate of the pump4, and the resulting gaseous phase refrigerant8amay be sucked into the pump4.FIG. 1Cschematically illustrates conditions in which such problems occur. When the gaseous phase refrigerant8agenerated in the evaporator2and discharged from the evaporator2is sucked into the pump4, and so-called biting of the pump4occurs, the feeding of the liquid phase refrigerant8from the pump4to the evaporator2is delayed. As a result, heating is continued in a state with a smaller amount of liquid phase refrigerant8. Thus, problems occur in that the function of the evaporator2is degraded, the gaseous phase refrigerant8adischarged after being generated in the evaporator2is further increased, and the biting of the gaseous phase refrigerant8aby the pump4occurs more easily.

Thus, depending on the configuration of the cooling system1, when the condition under which the boiling of the liquid phase refrigerant8occurs easily is used to enhance the cooling capacity of the evaporator2, there is a fear of being unable to perform stable circulation of the liquid phase refrigerant8by the pump4. There is consequently a fear of causing a degradation in the function of the evaporator2, and inviting overheating of the external heat generating body such as an electronic device or the like, and further inviting damage and performance degradation in the external heat generating body due to the overheating, because the external heat generating body is not cooled sufficiently.

In order to perform stable circulation of the liquid phase refrigerant8by the pump4in the cooling system1, a condition is used under which the amount of discharge of the gaseous phase refrigerant8afrom the evaporator2is reduced by reducing the amount of generation of the gaseous phase refrigerant8ain the evaporator2, or a condition is used under which a state as inFIG. 1B, for example, is obtained. However, under such a condition, the generation of the gaseous phase refrigerant8ain the evaporator2is suppressed. Therefore, an amount of heat absorbed in the evaporator2may be decreased, and a sufficient cooling capacity of the evaporator2may not be obtained. One electronic device as an example of the heat generating body to be cooled by the cooling system1is, for example, a processor. Amounts of heat generation of recent processors are increasing as the performance of the processors is enhanced, and the heat generation density of the recent processors is coming close to being comparable to a fuel rod surface temperature in a nuclear reactor. When the cooling capacity of the evaporator2is not sufficient in a case where the cooling system1is applied to such a processor, there is an increasing possibility of inviting overheating of the processor, and further inviting damage and performance degradation in the processor due to the overheating.

As described above, in the cooling system1, when the amount of generation of the gaseous phase refrigerant8ain the evaporator2is increased to enhance the cooling capacity of the evaporator2, the amount of discharge of the gaseous phase refrigerant8afrom the evaporator2is increased, and stable circulation of the liquid phase refrigerant8by the pump4may not be performed (FIG. 1C). On the other hand, in the cooling system1, when the amount of generation of the gaseous phase refrigerant8ain the evaporator2is reduced to perform stable circulation of the liquid phase refrigerant8by the pump4, a sufficient cooling capacity of the evaporator2may not be obtained (FIG. 1B).

In view of the points as described above, reducing the amount of discharge of the gaseous phase refrigerant from the evaporator while increasing the amount of generation of the gaseous phase refrigerant in the evaporator in the cooling system is considered to be effective in realizing stable pump circulation while realizing a high cooling capacity of the evaporator. The following description will be made of an evaporator enabling this and a cooling system including such an evaporator or the like as embodiments. Incidentally, in the following description, a gravitational direction G will be “downward,” and a direction opposite from the gravitational direction G will be “upward.”

First Embodiment

FIG. 2is a diagram of assistance in explaining a first example of an evaporator according to a first embodiment.FIG. 2schematically illustrates a fragmentary sectional view of the example of the evaporator.

An evaporator10A illustrated inFIG. 2includes a container11, a supplying unit12that supplies a liquid phase refrigerant20into the container11, a heat absorbing unit13in which the liquid phase refrigerant20within the container11absorbs heat from the outside, a storage part14that stores the liquid phase refrigerant20, and a discharging unit15that discharges the liquid phase refrigerant20within the container11. The evaporator10A further includes a supplying unit16that supplies the liquid phase refrigerant20along the surface of the container11and a discharging unit17that discharges the liquid phase refrigerant20.

The container11has, in an inner part11a, a space that may store a certain amount of liquid phase refrigerant20and a gaseous phase refrigerant21generated by boiling (may be referred to as “evaporation”, “vaporization”, and the like) of the liquid phase refrigerant20. The container11may be formed by a plurality of members such as a box-shaped main body and a lid covering the box-shaped main body or a bottom plate and a box-shaped main body covering the bottom plate as long as the container11thus has a certain space in the inner part11aand may store the liquid phase refrigerant20and the like. Here, a container11of a rectangular parallelepiped type is illustrated as an example. However, the shape of the container11is not limited to this, and it is possible to use containers11in various kinds of shapes such as a dome shape, a hanging bell shape, a drum shape, a hand drum shape, a sphere shape, and the like. A material excellent in thermal conductivity is used for the container11. For example, metallic materials and alloy materials such as copper, aluminum, brass, stainless steel, and the like are used for the container11. In addition, carbon materials such as graphite and the like or ceramic materials such as aluminum nitride, silicon carbide, and the like may be used for the container11.

The supplying unit12supplies the liquid phase refrigerant20to the inner part11aof the container11. The supplying unit12is, for example, coupled to a pump coupled to a radiator of a cooling system in which the evaporator10A is used. The liquid phase refrigerant20having a relatively low temperature, the liquid phase refrigerant20being condensed by the radiator and fed by the pump, is guided to the supplying unit12. The supplying unit12supplies the liquid phase refrigerant20to the inner part11aof the container11. For example, the liquid phase refrigerant20fed by the pump is branched, and a part of the branched liquid phase refrigerant20is guided to the supplying unit12and supplied to the inner part11aof the container11. A pipe extending from an upper portion to a lower portion of the container11, for example, is used as the supplying unit12. The supplying unit12is disposed such that an outlet12aof the supplying unit12reaches the heat absorbing unit13or is located in the vicinity of the heat absorbing unit13.

The heat absorbing unit13is a part where the liquid phase refrigerant20supplied to the inner part11aof the container11by the supplying unit12mainly absorbs heat from the outside (or receives heat or is heated). For example, the heat absorbing unit13is thermally coupled directly or indirectly to the external heat generating body such as an electronic device or the like to be cooled by the evaporator10A, and in the heat absorbing unit13, heat generated from the heat generating body is absorbed by the liquid phase refrigerant20supplied to the inner part11aof the container11. The heat absorbing unit13is provided so as to be located in a lower portion of the container11illustrated inFIG. 2, that is, a lower layer portion of the liquid phase refrigerant20stored in the inner part11aof the container11. The heat absorbing unit13may be formed, for example, by a plurality of fins13aprotruding from an inner surface11bto the inner part11aof the container11.

The storage part14is a part that stores (or collects) the liquid phase refrigerant20absorbing heat in the heat absorbing unit13and the liquid phase refrigerant20cooled and condensed after absorbing heat and evaporating in the heat absorbing unit13. A certain amount of liquid phase refrigerant20is stored in the storage part14. The liquid phase refrigerant20stored in the storage part14may include a gaseous phase refrigerant21generated by heat absorption in the heat absorbing unit13. In the inner part11aof the container11illustrated inFIG. 2, a space11cthat includes the gaseous phase refrigerant21generated from the liquid phase refrigerant20absorbing heat or which is a vacuum space is present above a liquid surface20aof the liquid phase refrigerant20stored in the storage part14. The volume of this space is set based on the amount of the liquid phase refrigerant20and pressure at a time of filling the liquid phase refrigerant20in a decompressed state into the closed circuit (sealed space) of the cooling system in which the evaporator10A is used. The storage part14stores a certain amount of liquid phase refrigerant20such that the space11chaving the set volume remains in the inner part11aof the container11.

The discharging unit15discharges the liquid phase refrigerant20stored in the storage part14or the liquid phase refrigerant20including the gaseous phase refrigerant21from the inner part11aof the container11to the outside. The discharging unit15is, for example, coupled to the radiator of the cooling system in which the evaporator10A is used. The liquid phase refrigerant20raised to a relatively high temperature in the evaporator10A or the liquid phase refrigerant20including the gaseous phase refrigerant21is discharged through the discharging unit15, and fed to the radiator. A pipe extending from the upper portion of the container11into the liquid phase refrigerant20in the storage part14is, for example, used as the discharging unit15. The discharging unit15is disposed such that an inlet15aof the discharging unit15is located below the liquid surface20aof the liquid phase refrigerant20.

The supplying unit16supplies the liquid phase refrigerant20along an outer surface11d(surface) of the container11. The supplying unit16is, for example, coupled to the pump coupled to the radiator of the cooling system in which the evaporator10A is used. The liquid phase refrigerant20at a relatively low temperature, the liquid phase refrigerant20being condensed by the radiator and fed by the pump, is guided to the supplying unit16. The supplying unit16supplies the liquid phase refrigerant20along the outer surface11dof the container11. For example, the liquid phase refrigerant20fed by the pump is branched, a part of the branched liquid phase refrigerant20is guided to the supplying unit12and supplied to the inner part11aof the container11, and another part of the branched liquid phase refrigerant20is guided to the supplying unit16and supplied along the outer surface11dof the container11. The liquid phase refrigerant20supplied by the supplying unit16is circulated along the outer surface11dof the container11, for example, from the upper portion to the lower portion of the container11in the example ofFIG. 2. While thus circulated from the upper portion to the lower portion, the circulated liquid phase refrigerant20exchanges heat with the inner part11aof the container11, and is consequently increased in temperature. The supplying unit16that circulates the liquid phase refrigerant20along the outer surface11dof the container11does not necessarily need to be in direct contact with the outer surface11das long as the supplying unit16is thermally coupled to the outer surface11d. For example, a thermally conductive layer may be interposed between the outer surface11dof the container11and the supplying unit16.

The discharging unit17discharges the liquid phase refrigerant20supplied and circulated along the outer surface11dof the container11by the supplying unit16to the outside of the evaporator10A. The discharging unit17is, for example, coupled to the radiator of the cooling system in which the evaporator10A is used. The liquid phase refrigerant20circulated along the outer surface11dof the container11is discharged through the discharging unit15, and is fed to the radiator. For example, the liquid phase refrigerant20discharged through the discharging unit17after being circulated along the outer surface11dof the container11is merged with the liquid phase refrigerant20discharged from the inner part11aof the container11through the discharging unit15, and is then fed to the radiator.

In the evaporator10A having the configuration as described above, for example, the liquid phase refrigerant20at a relatively low temperature, the liquid phase refrigerant20being fed from the pump coupled to the radiator of the cooling system in which the evaporator10A is used, is supplied from the supplying unit12to the inner part11aof the container11, and is stored in the storage part14. The liquid phase refrigerant20stored in the storage part14absorbs heat generated in the heat generating body such as an electronic device or the like to be cooled, through the heat absorbing unit13located in the lower layer portion of the liquid phase refrigerant20. Because the outlet12aof the supplying unit12reaches the heat absorbing unit13or is located in the vicinity of the heat absorbing unit13, the heat absorbing unit13is continuously supplied with the liquid phase refrigerant20at a relatively low temperature, the liquid phase refrigerant20being fed from the radiator by the pump. The liquid phase refrigerant20absorbing heat in the heat absorbing unit13may be vaporized in accordance with the heat. Because the heat is absorbed by the liquid phase refrigerant20, the heat generating body such as an external electronic device or the like is cooled. Due to the vaporization of the liquid phase refrigerant20absorbing the heat, the gaseous phase refrigerant21is generated. The gaseous phase refrigerant21moves (flows or diffuses) to the inside of the storage part14or the inside of the space11cin the inner part11aof the container11.

In the evaporator10A, the liquid phase refrigerant20at a relatively low temperature, the liquid phase refrigerant20being fed from the radiator by the pump, is supplied along the outer surface11dof the container11by the supplying unit16. In the evaporator10A, because the liquid phase refrigerant20at a relatively low temperature is thus supplied along the outer surface11dof the container11by the supplying unit16, wall portions of the container11(excluding a part corresponding to the heat absorbing unit13thermally coupled to the heat generating body) are cooled. The gaseous phase refrigerant21generated by the vaporizing (may be referred to as “boiling”, “evaporating”, and the like) of the liquid phase refrigerant20absorbing heat in the heat absorbing unit13and moving (flowing or diffusing) to the inner surface11bof the container11or the vicinity of the inner surface11bis thereby cooled and condensed. The cooling of the gaseous phase refrigerant21and the resulting condensation of the gaseous phase refrigerant21occur at least at one of the inside of the liquid phase refrigerant20and the inner surface11bof the container11or the vicinity of the inner surface11bin the storage part14and the inner surface11bor the vicinity of the inner surface11bwithin the space11c. When the gaseous phase refrigerant21is cooled and condensed in the liquid phase refrigerant20and at the inner surface11bor the vicinity of the inner surface11bin the storage part14, the liquid phase refrigerant20generated by the condensation is mixed in the liquid phase refrigerant20in the storage part14, and stored in the storage part14. When the gaseous phase refrigerant21is cooled and condensed at the inner surface11bor the vicinity of the inner surface11bwithin the space11c, the liquid phase refrigerant20generated by the condensation drops into the storage part14, or adheres to the inner surface11band flows down, is then mixed in the liquid phase refrigerant20in the storage part14, and is stored in the storage part14.

Incidentally, in the evaporator10A, not all of the gaseous phase refrigerant21generated by the heat absorption of the liquid phase refrigerant20necessarily needs to be cooled and condensed within the evaporator10A. There may be a case where a part of the gaseous phase refrigerant21generated by the heat absorption of the liquid phase refrigerant20remains without being condensed within the evaporator10A. The liquid phase refrigerant20stored in the storage part14may include the gaseous phase refrigerant21generated by the heat absorption of the liquid phase refrigerant20.

The liquid phase refrigerant20in the storage part14, the liquid phase refrigerant20being raised to a relatively high temperature due to heat absorption from the heat generating body, or the liquid phase refrigerant20including the gaseous phase refrigerant21is discharged to the outside of the evaporator10A through the discharging unit15having the inlet15alocated below the liquid surface20a. Positioning the inlet15aof the discharging unit15below the liquid surface20aof the liquid phase refrigerant20suppresses the discharging, to the outside, of the gaseous phase refrigerant21that may be present within the space11c. The liquid phase refrigerant20supplied along the outer surface11dof the container11by the supplying unit16and raised to a relatively high temperature by heat exchange with the inner part11ais discharged to the outside of the evaporator10A through the discharging unit17. The liquid phase refrigerant20discharged through the discharging unit15and the discharging unit17is, for example, fed to the radiator of the cooling system. Then, the liquid phase refrigerant20condensed and lowered in temperature by the heat radiation of the radiator is fed again by the pump to the supplying unit12and the supplying unit16of the evaporator10A.

Thus, in the evaporator10A, the gaseous phase refrigerant21generated in the inner part11aof the container11by the vaporizing (may be referred to as “boiling”, “evaporating”, and the like) of the liquid phase refrigerant20absorbing heat in the heat absorbing unit13is condensed by using the liquid phase refrigerant20supplied along the outer surface11dof the container11by the supplying unit16. That is, the evaporator10A has both of a cooling function of cooling the external heat generating body by absorbing heat generated from the heat generating body by the liquid phase refrigerant20and a condensing function of condensing the gaseous phase refrigerant21generated by the vaporizing of the liquid phase refrigerant20due to the heat absorption and thus returning the gaseous phase refrigerant21to the liquid phase refrigerant20. In the evaporator10A, the condensing function suppresses discharging of a large amount of gaseous phase refrigerant21from the discharging unit15together with the liquid phase refrigerant20. Because the discharging of a large amount of gaseous phase refrigerant21from the evaporator10A is suppressed, stable circulation of the liquid phase refrigerant20by the pump may be performed in the cooling system in which the evaporator10A is used. In the evaporator10A, stable circulation of the liquid phase refrigerant20may be performed while the condensing function suppresses the discharging of the gaseous phase refrigerant21. It is thus possible to use a condition under which the vaporizing of the liquid phase refrigerant20occurs easily. The cooling capacity of the evaporator10A may be thereby enhanced.

According to the evaporator10A as illustrated inFIG. 2, the amount of discharge of the gaseous phase refrigerant21to the outside is suppressed while the amount of generation of the gaseous phase refrigerant21due to the heat absorption of the liquid phase refrigerant20is increased, so that stable pump circulation may be realized while a high cooling capacity of the evaporator10A is realized.

Incidentally, in the evaporator10A, not all of the gaseous phase refrigerant21generated by the heat absorption of the liquid phase refrigerant20necessarily needs to be cooled and condensed within the evaporator10A. In the evaporator10A, even when not all of the gaseous phase refrigerant21generated by the heat absorption of the liquid phase refrigerant20is condensed within the evaporator10A, the amount of discharge of the gaseous phase refrigerant21to the outside of the evaporator10A is reduced, the discharging of a large amount of gaseous phase refrigerant21is suppressed, and thus stable pump circulation is realized.

FIG. 3is a diagram of assistance in explaining a second example of an evaporator according to the first embodiment.FIG. 3schematically illustrates a fragmentary sectional view of the example of the evaporator.

An evaporator10B illustrated inFIG. 3is different from the evaporator10A illustrated inFIG. 2described above in that the liquid phase refrigerant20supplied along the outer surface11dof the container11by the supplying unit16is circulated from the lower portion to the upper portion of the container11.

A heat absorbing unit13in which a liquid phase refrigerant20absorbs heat from an external heat generating body is provided to the lower portion of the container11(lower layer portion of the liquid phase refrigerant20in a storage part14). Therefore, the lower layer portion of the liquid phase refrigerant20in the storage part14, the heat absorbing unit13being disposed in the lower layer portion, is raised in temperature easily and is vaporized easily as compared with an upper layer portion of the liquid phase refrigerant20on a space11cside. That is, a gaseous phase refrigerant21occurs easily in the lower layer portion of the liquid phase refrigerant20stored in the storage part14.

In the evaporator10B illustrated inFIG. 3, the liquid phase refrigerant20is circulated along the outer surface11dof the evaporator10B from the lower portion to the upper portion of the container11. While thus circulated from the lower portion to the upper portion, the liquid phase refrigerant20is made to exchange heat with the inner part11aof the container11, and is consequently increased in temperature. Therefore, in the evaporator10B, the closer a part of the outer surface11dis to the lower layer portion of the liquid phase refrigerant20in the storage part14, the gaseous phase refrigerant21occurring easily in the lower layer portion of the liquid phase refrigerant20, the lower the temperature of the liquid phase refrigerant20circulated along the part becomes. The evaporator10B may thereby quickly condense the gaseous phase refrigerant21generated by heat absorption in the heat absorbing unit13(for example condense the gaseous phase refrigerant21in the liquid phase refrigerant20), and thus return the gaseous phase refrigerant21to the liquid phase refrigerant20.

The evaporator10B as illustrated inFIG. 3also suppresses the amount of discharge of the gaseous phase refrigerant21to the outside while increasing the amount of generation of the gaseous phase refrigerant21by the heat absorption of the liquid phase refrigerant20, so that stable pump circulation may be realized while a high cooling capacity of the evaporator10B is realized.

Second Embodiment

In the following, an example of an evaporator adopting the configuration as described above will be described as a second embodiment.

FIGS. 4 to 6Bare diagrams of assistance in explaining an example of the evaporator according to the second embodiment.FIG. 4schematically illustrates a fragmentary sectional view of the example of the evaporator.FIG. 5schematically illustrates a fragmentary plan view when the evaporator illustrated inFIG. 4is viewed from below.FIG. 6Aschematically illustrates an external view of a container of the evaporator illustrated inFIG. 4.FIG. 6Bschematically illustrates a sectional view taken along a line VI-VI ofFIG. 6A.

An evaporator100A illustrated inFIG. 4includes a container110, a supplying unit120that supplies a liquid phase refrigerant200into the container110, a heat absorbing unit130in which the liquid phase refrigerant200within the container110absorbs heat from an external heat generating body300, and a storage part140that stores the liquid phase refrigerant200. The evaporator100A further includes a supplying unit160that supplies the liquid phase refrigerant200along the surface of the container110and a discharging unit150that discharges the liquid phase refrigerant200within the container110and the liquid phase refrigerant200supplied to the surface of the container110by the supplying unit160. The evaporator100A also includes a guide180located in the liquid phase refrigerant200stored in the storage part140and disposed so as to cover the heat absorbing unit130and a plurality of fins190provided to the container110.

The container110has, in an inner part110a, a space that may store a certain amount of liquid phase refrigerant200and a gaseous phase refrigerant210generated by boiling (hereafter, may be referred to as “evaporation”, “vaporization”, and the like) of the liquid phase refrigerant200. The container110includes a bottom plate111, a dome-shaped main body112covering the bottom plate111, and a coupling portion113interposed between the bottom plate111and the main body112and coupling the bottom plate111and the main body112to each other. The inner part110aenclosed by the bottom plate111and the main body112coupled to each other via the coupling portion113stores the liquid phase refrigerant200and the gaseous phase refrigerant210generated by the boiling of the liquid phase refrigerant200. A material having a relatively high thermal conductivity is used for the bottom plate111and the main body112of the container110. For example, metallic materials and alloy materials such as copper, aluminum, brass, stainless steel, and the like are used for the bottom plate111and the main body112. In addition, carbon materials such as graphite and the like or ceramic materials such as aluminum nitride, silicon carbide, and the like may be used for the bottom plate111and the main body112. A material having a relatively low thermal conductivity is used for the coupling portion113of the container110. For example, an inorganic or organic heat insulating material is used for the coupling portion113. The use of a heat insulating material for the coupling portion113may inhibit heat transmitted from the external heat generating body300such as an electronic device or the like to be cooled by the evaporator100A to the bottom plate111from being directly transmitted to the main body112. As illustrated inFIG. 4andFIG. 5, the plurality of fins190protruding to the inner part110aare provided to an inner surface110bof the main body112of the container110.

The supplying unit120supplies the liquid phase refrigerant200to the inner part110aof the container110. The supplying unit120is, for example, coupled to a pump coupled to a radiator of a cooling system in which the evaporator100A is used. The liquid phase refrigerant200having a relatively low temperature, the liquid phase refrigerant200being condensed by the radiator and fed by the pump, is guided to the supplying unit120, and is supplied from the supplying unit120to the inner part110aof the container110. For example, the liquid phase refrigerant200fed by the pump is branched, and a part of the branched liquid phase refrigerant200is guided to the supplying unit120and supplied to the inner part110aof the container110. A pipe extending from an upper portion to a lower portion of the container110, for example, is used as the supplying unit120. The supplying unit120is disposed so as to penetrate the guide180covering the heat absorbing unit130. An outlet120aof the supplying unit120is disposed so as to reach the heat absorbing unit130or so as to be located in the vicinity of the heat absorbing unit130. As illustrated inFIG. 4, the liquid phase refrigerant200is supplied from the outlet120aof the supplying unit120to a region between the bottom plate111of the container110and the guide180, and moves (flows or diffuses) toward the inner surface110bof the main body112of the container110, as illustrated inFIG. 4andFIG. 5, while guided by the guide180.

The heat absorbing unit130is a part where the liquid phase refrigerant200supplied by the supplying unit120mainly absorbs heat from the external heat generating body300. For example, the heat absorbing unit130is thermally coupled to the heat generating body300, and heat generated from the heat generating body300is absorbed by the liquid phase refrigerant200in the heat absorbing unit130. The heat absorbing unit130is provided in the lower layer portion of the liquid phase refrigerant200in the storage part140in the lower portion of the container110illustrated inFIG. 4, and is provided between the bottom plate111of the container110and the guide180. The heat absorbing unit130is, for example, formed by a plurality of fins130adisposed on the bottom plate111of the container110so as to protrude to the inner part110a. Incidentally, the bottom plate111of the container110may be used as the heat absorbing unit130or a part of the heat absorbing unit130.

The guide180guides movement of the liquid phase refrigerant200supplied to the heat absorbing unit130or the vicinity of the heat absorbing unit130by the supplying unit120and absorbing heat in the heat absorbing unit130and the gaseous phase refrigerant210generated by the heat absorption toward the inner surface110bof the main body112of the container110. The guide180may inhibit the gaseous phase refrigerant210generated by the heat absorption in the heat absorbing unit130from being mixed into the liquid phase refrigerant200above the guide180in the storage part140and being discharged from the discharging unit150before reaching the inner surface110bof the main body112or the vicinity of the inner surface110b. A material having a relatively low thermal conductivity is used as the guide180. For example, an inorganic or organic heat insulating material is used as the guide180. The use of a heat insulating material for the guide180may inhibit heat in the heat absorbing unit130below the guide180from being transmitted to the liquid phase refrigerant200above the guide180in the storage part140.

The storage part140is a part that stores the liquid phase refrigerant200absorbing heat in the heat absorbing unit130and the liquid phase refrigerant200cooled and condensed after absorbing heat and evaporating in the heat absorbing unit130. A certain amount of liquid phase refrigerant200is stored in the storage part140. The liquid phase refrigerant200stored in the storage part140may include the gaseous phase refrigerant210generated by heat absorption in the heat absorbing unit130. In the inner part110aof the container110illustrated inFIG. 4, a space110cthat includes the gaseous phase refrigerant210generated from the liquid phase refrigerant200absorbing heat or which is a vacuum space is present above a liquid surface200aof the liquid phase refrigerant200in the storage part140. The volume of this space is set based on the amount of the liquid phase refrigerant200and pressure at a time of filling the liquid phase refrigerant200in a decompressed state into the closed circuit (sealed space) of the cooling system in which the evaporator100A is used. The storage part140stores a certain amount of liquid phase refrigerant200such that the space110chaving the set volume remains in the inner part110aof the container110.

As illustrated inFIG. 4, the discharging unit150discharges the liquid phase refrigerant200stored in the storage part140or the liquid phase refrigerant200including the gaseous phase refrigerant210from the inner part110aof the container110to the outside. The discharging unit150is, for example, coupled to the radiator of the cooling system in which the evaporator100A is used. The liquid phase refrigerant200raised to a relatively high temperature in the evaporator100A or the liquid phase refrigerant200including the gaseous phase refrigerant210is discharged through the discharging unit150, and fed to the radiator. A pipe extending from the upper portion of the container110into the liquid phase refrigerant200in the storage part140, for example, is used as the discharging unit150. The discharging unit150is disposed such that an inlet150aof the discharging unit150is located below the liquid surface200aof the liquid phase refrigerant200.

The supplying unit160supplies the liquid phase refrigerant200along an outer surface110d(surface) of the container110. The supplying unit160is, for example, supplied with the liquid phase refrigerant200branched in front of the container110(before introduction into the inner part110a) from the supplying unit120that supplies the liquid phase refrigerant200to the inner part110aof the container110. As illustrated inFIG. 4andFIGS. 6A and 6B, the supplying unit160includes a flow passage161through which the liquid phase refrigerant200is circulated from the upper portion to the lower portion of the container110and a flow passage162through which the liquid phase refrigerant200is returned at the lower portion of the container110and circulated to the upper portion. The flow passage161is a jacket type flow passage provided nearer to the outer surface110dof the container110. The flow passage161circulates, along the outer surface110d, the liquid phase refrigerant200distributed from a point of branching from the supplying unit120in front of the container110to the periphery of the container110. The flow passage162folded back from the flow passage161is a jacket type flow passage disposed on the outside of the flow passage161. The flow passage162circulates the liquid phase refrigerant200circulated through the flow passage161along the outside of the flow passage161. The inside flow passage161of the supplying unit160does not necessarily need to be in direct contact with the outer surface110das long as the flow passage161is thermally coupled to the outer surface110d. For example, a thermally conductive layer may be interposed between the outer surface110dof the container110and the inside flow passage161of the supplying unit160.

The flow passage162of the supplying unit160is coupled to the discharging unit150that discharges the liquid phase refrigerant200from the inner part110aof the container110. The liquid phase refrigerant200circulated through the flow passage162is merged with the liquid phase refrigerant200discharged from the inner part110aof the container110, and is discharged to the outside through the discharging unit150.

In the evaporator100A (FIG. 4) having the configuration as described above, for example, the liquid phase refrigerant200at a relatively low temperature, the liquid phase refrigerant200being fed from the pump coupled to the radiator of the cooling system in which the evaporator100A is used, is supplied to the inner part110aof the container110by the supplying unit120, and is stored in the storage part140. The liquid phase refrigerant200in the storage part140absorbs heat generated in the heat generating body300in the heat absorbing unit130located in the lower layer portion of the liquid phase refrigerant200. The supplying unit120penetrates the guide180covering the heat absorbing unit130, and the outlet120aof the supplying unit120reaches the heat absorbing unit130or is located in the vicinity of the heat absorbing unit130. Thus, the liquid phase refrigerant200at a relatively low temperature, the liquid phase refrigerant200being fed from the radiator by the pump, is continuously supplied to the heat absorbing unit130below the guide180. The liquid phase refrigerant200absorbing heat in the heat absorbing unit130may be vaporized in accordance with the heat. Because the heat is absorbed by the liquid phase refrigerant200, the heat generating body300is cooled. Due to the boiling of the liquid phase refrigerant200absorbing the heat, the liquid phase refrigerant200evaporates, and the gaseous phase refrigerant210is generated. The gaseous phase refrigerant210and the liquid phase refrigerant200including the gaseous phase refrigerant210move toward the inner surface110bof the main body112of the container110while guided by the guide180above the heat absorbing unit130, and further move upward along the inner surface110b.

In the evaporator100A, the liquid phase refrigerant200at a relatively low temperature, the liquid phase refrigerant200being fed from the radiator by the pump, is supplied along the outer surface110dof the container110by the supplying unit160, circulated from the upper portion to the lower portion of the container110, and further returned and circulated from the lower portion to the upper portion. In the evaporator100A, the main body112of the container110is cooled by thus supplying the liquid phase refrigerant200at a relatively low temperature along the outer surface110dof the container110by the supplying unit160(the flow passage161and the flow passage162, particularly the inside flow passage161). The gaseous phase refrigerant210is thereby cooled and condensed, the gaseous phase refrigerant210being generated by the boiling of the liquid phase refrigerant200absorbing heat in the heat absorbing unit130and moving to the inner surface110bof the main body112of the container110(inner surface110bon the outside of the liquid phase refrigerant200in the storage part140) or the vicinity of the inner surface110b. In the evaporator100A, the inner surface110bof the main body112is provided with the fins190to be increased in surface area, and therefore such cooling of the gaseous phase refrigerant210and resulting condensation of the gaseous phase refrigerant210are promoted. The cooling of the gaseous phase refrigerant210and the resulting condensation of the gaseous phase refrigerant210occur at least at one of the inside of the liquid phase refrigerant200and the inner surface110bof the container110or the vicinity of the inner surface110bin the storage part140and the inner surface110bor the vicinity of the inner surface110bwithin the space110c. When the gaseous phase refrigerant210is cooled and condensed in the liquid phase refrigerant200and at the inner surface110bor the vicinity of the inner surface110b, the liquid phase refrigerant200generated by the condensation is mixed in the liquid phase refrigerant200in the storage part140, and stored in the storage part140. When the gaseous phase refrigerant210is cooled and condensed at the inner surface110bor the vicinity of the inner surface110bwithin the space110c, the liquid phase refrigerant200generated by the condensation drops into the storage part140, or adheres to the inner surface110band flows down, is then mixed in the liquid phase refrigerant200in the storage part140, and is stored in the storage part140.

Incidentally, in the evaporator100A, not all of the gaseous phase refrigerant210generated by the heat absorption of the liquid phase refrigerant200necessarily needs to be cooled and condensed within the evaporator100A. There may be a case where a part of the gaseous phase refrigerant210generated by the heat absorption of the liquid phase refrigerant200remains without being condensed within the evaporator100A. The liquid phase refrigerant200stored in the storage part140may include the gaseous phase refrigerant210generated by the heat absorption of the liquid phase refrigerant200.

The liquid phase refrigerant200in the storage part140, the liquid phase refrigerant200being raised to a relatively high temperature due to heat absorption from the heat generating body300, or the liquid phase refrigerant200including the gaseous phase refrigerant210is discharged to the outside of the evaporator100A through the discharging unit150having the inlet150alocated below the liquid surface200a. Positioning the inlet150aof the discharging unit150below the liquid surface200aof the liquid phase refrigerant200suppresses the discharging of the gaseous phase refrigerant210that may be present within the space110c. The liquid phase refrigerant200supplied along the outer surface110dof the container110by the supplying unit160and raised to a relatively high temperature by heat exchange with the inner part110ais merged with the liquid phase refrigerant200discharged through the discharging unit150, and is discharged to the outside of the evaporator100A. The liquid phase refrigerant200discharged through the discharging unit150or the liquid phase refrigerant200including the gaseous phase refrigerant210is fed to the radiator of the cooling system. Then, the liquid phase refrigerant200condensed and lowered in temperature by the heat radiation of the radiator is fed again by the pump to the supplying unit120and the supplying unit160of the evaporator100A.

Thus, in the evaporator100A, the gaseous phase refrigerant210generated in the inner part110aof the container110by the boiling of the liquid phase refrigerant200absorbing heat in the heat absorbing unit130is condensed by using the liquid phase refrigerant200supplied along the outer surface110dof the container110by the supplying unit160. That is, the evaporator100A has both of a cooling function of cooling the external heat generating body300by absorbing heat generated from the heat generating body300by the liquid phase refrigerant200and a condensing function of condensing the gaseous phase refrigerant210generated by the boiling of the liquid phase refrigerant200due to the heat absorption and thus returning the gaseous phase refrigerant210to the liquid phase refrigerant200. In the evaporator100A, the condensing function suppresses discharging of a large amount of gaseous phase refrigerant210from the discharging unit150together with the liquid phase refrigerant200. Because the discharging of a large amount of gaseous phase refrigerant210from the evaporator100A is suppressed, stable circulation of the liquid phase refrigerant200by the pump may be performed in the cooling system in which the evaporator100A is used. In the evaporator100A, stable circulation of the liquid phase refrigerant200may be performed while the condensing function suppresses the discharging of the gaseous phase refrigerant210. It is thus possible to use a condition under which the boiling of the liquid phase refrigerant200occurs easily. The cooling capacity of the evaporator100A may be thereby enhanced.

According to the evaporator100A, the amount of discharge of the gaseous phase refrigerant210to the outside is suppressed while the amount of generation of the gaseous phase refrigerant210due to the heat absorption of the liquid phase refrigerant200is increased, so that stable pump circulation may be realized while a high cooling capacity of the evaporator100A is realized. Further, in a case where a pipe coupled to the radiator from the evaporator100A is thin, for example, in the cooling system in which the evaporator100A is used, the discharging of the gaseous phase refrigerant210to such a pipe is suppressed, so that damage to the pipe due to steam hammering or the like may be suppressed.

Incidentally, in the evaporator100A, not all of the gaseous phase refrigerant210generated by the heat absorption of the liquid phase refrigerant200necessarily needs to be cooled and condensed within the evaporator100A. In the evaporator100A, even when not all of the gaseous phase refrigerant210generated by the heat absorption of the liquid phase refrigerant200is condensed within the evaporator100A, the amount of discharge of the gaseous phase refrigerant210to the outside is reduced, the discharging of a large amount of the gaseous phase refrigerant210is suppressed, and thus stable pump circulation is realized.

The cooling system in which the evaporator100A as described above is used is a sealed structure, and the liquid phase refrigerant200is filled in a decompressed state. In such a cooling system, the space that includes the gaseous phase refrigerant210generated by the evaporation of the liquid phase refrigerant200or which is close to a vacuum has a fixed volume. Accordingly, the container110of the evaporator100A is set to a volume exceeding twice the above-described fixed volume in consideration of volumetric expansion at a time of a phase change to the gaseous phase refrigerant210, and to a volume that stores the liquid phase refrigerant200to such a degree as to be able to cover the inlet150aof the discharging unit150even when the evaporator100A is set in an arbitrary installation attitude. Thus, a state in which the inlet150aof the discharging unit150is submerged in the liquid phase refrigerant200at all times may be obtained irrespective of the installation attitude of the evaporator100A, and thereby discharging of the gaseous phase refrigerant210from the discharging unit150may be suppressed.

FIG. 7andFIG. 8are diagrams of assistance in explaining an example in which an installation attitude of an evaporator according to the second embodiment is changed.FIG. 7andFIG. 8each schematically illustrate a fragmentary sectional view of an example of the evaporator.

FIG. 7represents an example in a case where the evaporator100A illustrated inFIG. 4described above is installed upside down. In the present example, the supplying unit120having the outlet120alocated above the guide180supplies the liquid phase refrigerant200to the heat absorbing unit130or the vicinity of the heat absorbing unit130. The gaseous phase refrigerant210generated by heat absorption from the heat generating body300in the heat absorbing unit130above the guide180and the liquid phase refrigerant200including the gaseous phase refrigerant210flow out from between the guide180and the inner surface110bof the main body112of the container110. The main body112of the container110is cooled by the liquid phase refrigerant200circulated along the outer surface110dby the supplying unit160. The gaseous phase refrigerant210at the inner surface110bor the vicinity of the inner surface110bor the gaseous phase refrigerant210in the liquid phase refrigerant200is thereby condensed. The liquid phase refrigerant200or the liquid phase refrigerant200including the gaseous phase refrigerant210in the inner part110aof the container110and the liquid phase refrigerant200circulated along the outer surface110dare discharged to the outside of the evaporator100A through the discharging unit150. Because the container110of the evaporator100A is set to the given volume as described above, the evaporator100A may also be installed upside down as illustrated inFIG. 7, for example. Because the container110is set to the given volume, the inlet150aof the discharging unit150is located below the liquid surface200aof the liquid phase refrigerant200even when the evaporator100A is thus installed upside down, and therefore the discharging of the gaseous phase refrigerant210from the discharging unit150is suppressed.

In addition,FIG. 8represents an example in a case where the evaporator100A illustrated inFIG. 4described above is installed horizontally. In the present example, the supplying unit120having the outlet120alocated more to the heat absorbing unit130side than the guide180supplies the liquid phase refrigerant200to the heat absorbing unit130or the vicinity of the heat absorbing unit130. The gaseous phase refrigerant210generated by heat absorption from the heat generating body300in the heat absorbing unit130on the side of the guide180and the liquid phase refrigerant200including the gaseous phase refrigerant210flow out from between the guide180and the inner surface110bof the main body112of the container110. The main body112of the container110is cooled by the liquid phase refrigerant200circulated along the outer surface110dby the supplying unit160. The gaseous phase refrigerant210at the inner surface110bor the vicinity of the inner surface110bor the gaseous phase refrigerant210in the liquid phase refrigerant200is thereby condensed. The liquid phase refrigerant200or the liquid phase refrigerant200including the gaseous phase refrigerant210in the inner part110aof the container110and the liquid phase refrigerant200circulated along the outer surface110dare discharged to the outside of the evaporator100A through the discharging unit150. Because the container110of the evaporator100A is set to the given volume as described above, the evaporator100A may also be installed horizontally as illustrated inFIG. 8, for example. Because the container110is set to the given volume, the inlet150aof the discharging unit150is located below the liquid surface200aof the liquid phase refrigerant200even when the evaporator100A is thus installed horizontally, and therefore the discharging of the gaseous phase refrigerant210from the discharging unit150is suppressed.

Thus, in the evaporator100A in an arbitrary installation attitude, the inlet150aof the discharging unit150is positioned below the liquid surface200aof the liquid phase refrigerant200, so that the discharging of the gaseous phase refrigerant210from the discharging unit150may be suppressed. Consequently, stable circulation of the liquid phase refrigerant200may be performed by suppressing the discharging of the gaseous phase refrigerant210, and the cooling capacity may be enhanced by using a condition under which the boiling of the liquid phase refrigerant200occurs easily. Further, even in the case where the pipe coupled to the evaporator100A is thin, the discharging of the gaseous phase refrigerant210to such a pipe is suppressed, so that damage to the pipe due to steam hammering or the like may be suppressed.

In the above description, the supplying unit having a structure including the jacket type flow passage161nearer to the outer surface110dand the jacket type flow passage162on the outside, the flow passages161and162covering the container110, is illustrated as the supplying unit160that supplies the liquid phase refrigerant200along the outer surface110dof the container110of the evaporator100A. The structure of the supplying unit160is not limited to such a structure.

FIGS. 9A and 9Bare diagrams of assistance in explaining a modification of an evaporator according to the second embodiment.FIG. 9AandFIG. 9Beach schematically illustrate an external view of an example of a container of an evaporator and a supplying unit provided to the outer surface of the container.

The evaporator100A may be provided with a supplying unit160A including a plurality of folded pipes163as illustrated inFIG. 9A, for example, as the supplying unit that supplies the liquid phase refrigerant200along the outer surface110dof the container110. For example, the liquid phase refrigerant200in the supplying unit120communicating with the inner part110aof the container110is branched and supplied to the plurality of pipes163by a regulator164. Return liquid phase refrigerants200in the plurality of pipes163are merged with each other in the regulator164, merged with the liquid phase refrigerant200in the discharging unit150, and discharged. Also with such pipes163, the liquid phase refrigerant200circulated through the pipes163cools the outer surface110dof the container110, and the inner part110ais thereby cooled, so that the gaseous phase refrigerant210is condensed.

In addition, the evaporator100A may be provided with a supplying unit160B including a spiral-shaped pipe165wound around the container110as illustrated inFIG. 9B, for example, as the supplying unit that supplies the liquid phase refrigerant200along the outer surface110dof the container110. For example, the liquid phase refrigerant200in the supplying unit120communicating with the inner part110aof the container110is branched and supplied to the pipe165by a regulator166. A return liquid phase refrigerant200in the pipe165is merged with the liquid phase refrigerant200in the discharging unit150by the regulator166, and discharged. Also with such a pipe165, the liquid phase refrigerant200circulated through the pipe165cools the outer surface110dof the container110, and the inner part110ais thereby cooled, so that the gaseous phase refrigerant210is condensed.

Third Embodiment

FIG. 10is a diagram of assistance in explaining an example of an evaporator according to a third embodiment.FIG. 10schematically illustrates a fragmentary sectional view of the example of the evaporator.

An evaporator100B illustrated inFIG. 10has a guide180B that covers a heat absorbing unit130and is extended to the vicinity of a supplying unit120and a discharging unit150along an inner surface110bof a main body112of a container110. The evaporator100B further includes a barrier181B provided to the supplying unit120and the discharging unit150so as to be located in an inner part110aof the container110and at a liquid surface200aof a liquid phase refrigerant200in a storage part140or above the liquid surface200a. The evaporator100B is different from the evaporator100A (FIGS. 4 to 8) described in the foregoing second embodiment in such a respect.

A part of the guide180B, the part being extended to the vicinity of the supplying unit120and the discharging unit150along the inner surface110bof the main body112of the container110, is disposed on the inside of fins190protruding from the inner surface110b. The guide180B guides movement of the liquid phase refrigerant200supplied to the heat absorbing unit130or the vicinity of the heat absorbing unit130by the supplying unit120and absorbing heat in the heat absorbing unit130and a gaseous phase refrigerant210generated by the heat absorption, the movement being a movement toward the inner surface110bof the main body112of the container110and a movement along the inner surface110b. The guide180B may inhibit the gaseous phase refrigerant210generated by the heat absorption in the heat absorbing unit130from being mixed into the liquid phase refrigerant200in the storage part140inside the guide180B and being discharged from the discharging unit150before reaching the inner surface110bof the main body112or the vicinity of the inner surface110b. A material having a relatively low thermal conductivity, for example, an inorganic or organic heat insulating material is used for the guide180B. The use of a heat insulating material suppresses heat exchange between the inside and outside of the guide180B.

In the evaporator100B, the supplying unit120having an outlet120alocated below a part of the guide180B, the part covering the heat absorbing unit130, supplies the liquid phase refrigerant200to the heat absorbing unit130or the vicinity of the heat absorbing unit130. The gaseous phase refrigerant210generated by heat absorption from a heat generating body300in the heat absorbing unit130and the liquid phase refrigerant200including the gaseous phase refrigerant210move toward the inner surface110bof the main body112of the container110while guided by a part of the guide180B, the part covering the heat absorbing unit130. The gaseous phase refrigerant210and the liquid phase refrigerant200including the gaseous phase refrigerant210after moving toward the inner surface110bof the main body112of the container110further move between the inner surface110bof the main body112and the guide180B to the vicinity of the supplying unit120and the discharging unit150.

The gaseous phase refrigerant210moved to the inner surface110bof the main body112of the container110or the vicinity of the inner surface110band the gaseous phase refrigerant210moving between the inner surface110bof the main body112and the guide180B are cooled and condensed by the liquid phase refrigerant200circulated along an outer surface110dby a supplying unit160. The liquid phase refrigerant200in which the gaseous phase refrigerant210is condensed or the liquid phase refrigerant200including the gaseous phase refrigerant210flows down to a space110cand the storage part140from an opening180Ba of the guide180B, the opening180Ba being disposed in the vicinity of the supplying unit120and the discharging unit150. The liquid phase refrigerant200or the liquid phase refrigerant200including the gaseous phase refrigerant210in the storage part140and the liquid phase refrigerant200circulated along the outer surface110dare discharged to the outside of the evaporator100B through the discharging unit150.

The barrier181B is provided where the liquid phase refrigerant200flowing down from the opening180Ba of the guide180B flows in. The barrier181B suppresses the mixing in of the gaseous phase refrigerant210included in the liquid phase refrigerant200flowing down from the opening180Ba of the guide180B, the mixing of the gaseous phase refrigerant210into the space110c, and the mixing in of the gaseous phase refrigerant210as the liquid phase refrigerant200in the storage part140waves during the flow-down.

Thus, in the evaporator100B, the guide180B moves the gaseous phase refrigerant210generated by the boiling of the liquid phase refrigerant200absorbing heat in the heat absorbing unit130along the inner surface110bof the main body112of the container110. Because the gaseous phase refrigerant210is thus moved along the inner surface110bof the main body112of the container110, the gaseous phase refrigerant210is effectively cooled and condensed by using the liquid phase refrigerant200supplied along the outer surface110dof the main body112of the container110by the supplying unit160.

The evaporator100B, also, may suppress the amount of discharge of the gaseous phase refrigerant210to the outside while increasing the amount of generation of the gaseous phase refrigerant210due to heat absorption. Thus, stable pump circulation may be realized while a high cooling capacity of the evaporator100B is realized.

Incidentally, in the evaporator100B, not all of the gaseous phase refrigerant210generated by the heat absorption of the liquid phase refrigerant200necessarily needs to be cooled and condensed within the evaporator100B. In the evaporator100B, even when not all of the gaseous phase refrigerant210generated by the heat absorption of the liquid phase refrigerant200is condensed within the evaporator100B, the amount of discharge of the gaseous phase refrigerant210to the outside of the evaporator100B is reduced, and thus stable pump circulation is realized.

The evaporator100B may also be set in an arbitrary installation attitude by setting the container110to a given volume.

FIG. 11andFIG. 12are diagrams of assistance in explaining examples in which an installation attitude of an evaporator according to the third embodiment is changed.FIG. 11andFIG. 12each schematically illustrate a fragmentary sectional view of an example of the evaporator.

FIG. 11represents an example in a case where the evaporator100B illustrated inFIG. 10described above is installed upside down. In the present example, the supplying unit120having the outlet120alocated above the guide180B supplies the liquid phase refrigerant200to the heat absorbing unit130or the vicinity of the heat absorbing unit130. The gaseous phase refrigerant210generated by heat absorption from the heat generating body300in the heat absorbing unit130and the liquid phase refrigerant200including the gaseous phase refrigerant210move toward the inner surface110bof the main body112of the container110and further move along the inner surface110bwhile guided by the guide180B, and flow out from the opening180Ba. The main body112of the container110is cooled by the liquid phase refrigerant200circulated along the outer surface110dby the supplying unit160. The gaseous phase refrigerant210at the inner surface110bor the vicinity of the inner surface110band the gaseous phase refrigerant210moving along the inner surface110bare thereby condensed. The liquid phase refrigerant200or the liquid phase refrigerant200including the gaseous phase refrigerant210in the inner part110aof the container110and the liquid phase refrigerant200circulated along the outer surface110dare discharged to the outside of the evaporator100B through the discharging unit150. Because the container110of the evaporator100B is set to the given volume, the evaporator100B may also be installed upside down as illustrated inFIG. 11, for example. Because the container110is set to the given volume, the inlet150aof the discharging unit150is located below the liquid surface200aof the liquid phase refrigerant200even when the evaporator100B is installed upside down, and therefore the discharging of the gaseous phase refrigerant210from the discharging unit150is suppressed.

In addition,FIG. 12represents an example in a case where the evaporator100B illustrated inFIG. 10described above is installed horizontally. In the present example, the supplying unit120having the outlet120alocated more to the heat absorbing unit130side than the guide180B supplies the liquid phase refrigerant200to the heat absorbing unit130or the vicinity of the heat absorbing unit130. The gaseous phase refrigerant210generated by heat absorption from the heat generating body300in the heat absorbing unit130and the liquid phase refrigerant200including the gaseous phase refrigerant210move toward the inner surface110bof the main body112of the container110and further move along the inner surface110bwhile guided by the guide180B, and flow out from the opening180Ba. The main body112of the container110is cooled by the liquid phase refrigerant200circulated along the outer surface110dby the supplying unit160. The gaseous phase refrigerant210at the inner surface110bor the vicinity of the inner surface110band the gaseous phase refrigerant210moving along the inner surface110bare thereby condensed. The liquid phase refrigerant200or the liquid phase refrigerant200including the gaseous phase refrigerant210in the inner part110aof the container110and the liquid phase refrigerant200circulated along the outer surface110dare discharged to the outside of the evaporator100B through the discharging unit150. Because the container110of the evaporator100B is set to the given volume, the evaporator100B may also be installed horizontally as illustrated inFIG. 12, for example. Because the container110is set to the given volume, the inlet150aof the discharging unit150is located below the liquid surface200aof the liquid phase refrigerant200even when the evaporator100B is installed horizontally, and therefore the discharging of the gaseous phase refrigerant210from the discharging unit150is suppressed.

Fourth Embodiment

FIG. 13is a diagram of assistance in explaining an example of an evaporator according to a fourth embodiment.FIG. 13schematically illustrates a fragmentary sectional view of the example of the evaporator.

An evaporator100C illustrated inFIG. 13includes a container110C including a bottom plate111, a main body112covering the bottom plate111, a secondary main body114disposed on the inside of the main body112, and a coupling portion113interposed between the bottom plate111and the main body112and the secondary main body114and coupling the bottom plate111to the main body112and the secondary main body114. A flow passage167that makes a liquid phase refrigerant200circulated along the main body112and the secondary main body114is disposed between the main body112and the secondary main body114. The flow passage167functions as a supplying unit160(or a part of the supplying unit160) that supplies the liquid phase refrigerant200along the surface of the container110C. The liquid phase refrigerant200to be supplied to an inner part110aof the container110C by a supplying unit120, for example, is branched and supplied to the flow passage167. A plurality of holes114apenetrating the secondary main body114of the container110C and communicating with the flow passage167are provided to the secondary main body114of the container110C. The liquid phase refrigerant200circulated through the flow passage167from an upper portion to a lower portion of the container110is introduced into the inner part110aof the container110C from the plurality of holes114aprovided to the secondary main body114of the container110C. A heat insulating material is preferably used for the secondary main body114of the container110C to suppress heat exchange between the liquid phase refrigerant200circulated through the flow passage167and the inner part110aof the container110C. Incidentally, the fins190as described above are not provided in the evaporator100C. The evaporator100C is different from the evaporator100A (FIGS. 4 to 8) described in the foregoing second embodiment in such a respect.

In the evaporator100C, the supplying unit120having an outlet120alocated below a guide180supplies the liquid phase refrigerant200to a heat absorbing unit130or the vicinity of the heat absorbing unit130. A gaseous phase refrigerant210generated by heat absorption from a heat generating body300in the heat absorbing unit130and the liquid phase refrigerant200including the gaseous phase refrigerant210move toward an inner surface110bof the container110C (secondary main body114of the container110C). The gaseous phase refrigerant210and the liquid phase refrigerant200including the gaseous phase refrigerant210that have moved toward the inner surface110bof the container110C further move upward along the secondary main body114.

The liquid phase refrigerant200circulated through the flow passage167is introduced into the inner part110aof the container110C from the holes114aof the secondary main body114. For example, the liquid phase refrigerant200circulated through the flow passage167is jetted from the holes114aof the secondary main body114to the inner part110a. The liquid phase refrigerant200introduced from the holes114aof the secondary main body114cools the gaseous phase refrigerant210and the liquid phase refrigerant200including the gaseous phase refrigerant210in the inner part110a(within a space110cand within a storage part140), and condenses the gaseous phase refrigerant210. The liquid phase refrigerant200at a relatively low temperature is, for example, branched from the supplying unit120and supplied to the flow passage167, the liquid phase refrigerant200being fed from a pump coupled to a radiator of a cooling system in which the evaporator100C is used. When the liquid phase refrigerant200at such a relatively low temperature is directly introduced into the inner part110athrough the holes114aof the secondary main body114of the container110C, the gaseous phase refrigerant210and the liquid phase refrigerant200including the gaseous phase refrigerant210in the inner part110aare cooled sharply, and the gaseous phase refrigerant210is condensed effectively. The liquid phase refrigerant200generated by the condensation is stored in the storage part140. The liquid phase refrigerant200or the liquid phase refrigerant200including the gaseous phase refrigerant210in the storage part140is discharged to the outside of the evaporator100C through a discharging unit150.

The evaporator100C, also, may suppress the amount of discharge of the gaseous phase refrigerant210to the outside while increasing the amount of generation of the gaseous phase refrigerant210due to heat absorption. Thus, stable pump circulation may be realized while a high cooling capacity of the evaporator100C is realized.

Incidentally, in the evaporator100C, not all of the gaseous phase refrigerant210generated by the heat absorption of the liquid phase refrigerant200necessarily needs to be cooled and condensed within the evaporator100C. In the evaporator100C, even when not all of the gaseous phase refrigerant210generated by the heat absorption of the liquid phase refrigerant200is condensed within the evaporator100C, the amount of discharge of the gaseous phase refrigerant210to the outside of the evaporator100C is reduced, and thus stable pump circulation is realized.

In addition, in the evaporator100C, an inlet150aof the discharging unit150may be positioned below a liquid surface200aof the liquid phase refrigerant200in an arbitrary installation attitude by setting the container110C to a given volume as described in relation to the above-described evaporator100A or the like. Thus, the evaporator100C set in an arbitrary installation attitude may suppress the discharging of the gaseous phase refrigerant210from the discharging unit150.

Fifth Embodiment

FIG. 14is a diagram of assistance in explaining an example of an evaporator according to a fifth embodiment.FIG. 14schematically illustrates a fragmentary sectional view of the example of the evaporator.

An evaporator100D illustrated inFIG. 14includes a plurality of fins191on the outside of a supplying unit160that supplies a liquid phase refrigerant200along an outer surface110dof a container110, the plurality of fins191being disposed so as to be thermally coupled to the supplying unit160. The evaporator100D is different from the evaporator100A (FIGS. 4 to 8) described in the foregoing second embodiment in such a respect.

The liquid phase refrigerant200supplied to the supplying unit160is increased in temperature by heat exchange with an inner part110awhile circulated through an inside flow passage161from an upper portion to a lower portion of the container110. The liquid phase refrigerant200circulated through the inside flow passage161is further increased in temperature by heat exchange with the inner part110aand the inside flow passage161while returned and circulated through an outside flow passage162from the lower portion to the upper portion of the container110. When the plurality of fins191thermally coupled to the supplying unit160are arranged on the outside of the supplying unit160as in the evaporator100D, the surface area of the supplying unit160is increased, and thus efficiency of heat radiation from the supplying unit160is enhanced. Consequently, an increase in the temperature of the liquid phase refrigerant200circulated through the supplying unit160is suppressed, and the temperature of the liquid phase refrigerant200fed to a radiator of a cooling system through a discharging unit150, for example, is decreased, so that efficiency of heat radiation in the radiator is enhanced. In addition, the boiling of the liquid phase refrigerant200circulated through the supplying unit160and resulting generation of a gaseous phase refrigerant210are suppressed.

The evaporator100D, also, may suppress the amount of discharge of the gaseous phase refrigerant210to the outside while increasing the amount of generation of the gaseous phase refrigerant210due to heat absorption. Thus, stable pump circulation may be realized while a high cooling capacity of the evaporator100D is realized.

Incidentally, a method of providing the outside of the supplying unit160with the plurality of fins191thermally coupled to the supplying unit160as in the evaporator100D may be similarly applied also to the evaporator100B (FIGS. 10 to 12) described in the foregoing third embodiment. In addition, the method of thus providing the plurality of fins191may be similarly applied also to the main body112of the container110of the evaporator100C (FIG. 13) described in the foregoing fourth embodiment.

Sixth Embodiment

FIG. 15is a diagram of assistance in explaining an example of an evaporator according to a sixth embodiment.FIG. 15schematically illustrates a fragmentary sectional view of the example of the evaporator.

An evaporator100E illustrated inFIG. 15includes a supplying unit160E having an inside flow passage161, an outside flow passage162, and a heat insulating layer168interposed between the inside flow passage161and the outside flow passage162. The evaporator100E is different from the evaporator100A (FIGS. 4 to 8) described in the foregoing second embodiment in such a respect.

A liquid phase refrigerant200supplied to the supplying unit160E is increased in temperature by heat exchange with an inner part110awhile circulated through the inside flow passage161from an upper portion to a lower portion of a container110. The liquid phase refrigerant200circulated through the inside flow passage161is further increased in temperature by heat exchange with the inner part110aand the inside flow passage161while returned and circulated through the outside flow passage162from the lower portion to the upper portion of the container110. The interposition of the heat insulating layer168between the inside flow passage161and the outside flow passage162as in the evaporator100E suppresses heat exchange between the outside flow passage162and the inside flow passage161and heat exchange between the outside flow passage162and the inner part110a. Consequently, an increase in the temperature of the liquid phase refrigerant200circulated through the outside flow passage162is suppressed, and an increase in the temperature of the liquid phase refrigerant200circulated through the inside flow passage161is thereby suppressed. The liquid phase refrigerant200whose temperature increase is thus suppressed flows into the outside flow passage162. According to the evaporator100E, an increase in the temperature of the liquid phase refrigerant200circulated through the supplying unit160E is suppressed. In the evaporator100E, the temperature of the liquid phase refrigerant200fed to a radiator of a cooling system through a discharging unit150, for example, is decreased, so that efficiency of heat radiation in the radiator is enhanced. In addition, in the evaporator100E, the boiling of the liquid phase refrigerant200circulated through the supplying unit160E and resulting generation of a gaseous phase refrigerant210are suppressed effectively.

The evaporator100E, also, may suppress the amount of discharge of the gaseous phase refrigerant210to the outside while increasing the amount of generation of the gaseous phase refrigerant210due to heat absorption. Thus, stable pump circulation may be realized while a high cooling capacity of the evaporator100E is realized.

Incidentally, a method of interposing the heat insulating layer168between the inside flow passage161and the outside flow passage162of the supplying unit160E as in the evaporator100E may be similarly applied also to the evaporator100B (FIGS. 10 to 12) described in the foregoing third embodiment. In addition, the method of thus interposing the heat insulating layer168between the inside flow passage161and the outside flow passage162may be similarly applied also to the evaporator100D (FIG. 14) described in the foregoing fifth embodiment.

Seventh Embodiment

FIG. 16is a diagram of assistance in explaining an example of an evaporator according to a seventh embodiment.FIG. 16schematically illustrates a fragmentary sectional view of the example of the evaporator.

In an evaporator100F illustrated inFIG. 16, an inlet160bof a supplying unit160that supplies a liquid phase refrigerant200along an outer surface110dof a container110is provided so as to be separated from an inlet120bof a supplying unit120that supplies the liquid phase refrigerant200to an inner part110aof the container110. In the evaporator100F, further, an outlet170bof a discharging unit170that discharges the liquid phase refrigerant200supplied along the outer surface110dof the container110is provided so as to be separated from an outlet150bof a discharging unit150that discharges the liquid phase refrigerant200in the inner part110aof the container110. The evaporator100F is different from the evaporator100A (FIGS. 4 to 8) described in the foregoing second embodiment in such a respect.

In the evaporator100F, two pipes extending from a pump coupled to a radiator of a cooling system or two pipes branched from one pipe extending from the pump are, for example, coupled to the inlet160bof the supplying unit160and the inlet120bof the supplying unit120, respectively. In addition, in the evaporator100F, pipes are, for example, coupled to the outlet170bof the discharging unit170and the outlet150bof the discharging unit150, respectively. The two pipes are each extended to the radiator and coupled to the radiator. Alternatively, the two pipes are coupled to one pipe in front of the radiator, and the one pipe is coupled to the radiator.

The configuration of the inlets and outlets, branching point, and merging point of the liquid phase refrigerant is not limited as long as the liquid phase refrigerant200may be supplied to the outer surface110dand the inner part110aof the container110and the liquid phase refrigerant200may be discharged from the outer surface110dand the inner part110aof the container110.

Incidentally, a method of providing the inlets120band160bof the supplying units120and160and the outlets150band170bof the discharging units150and170as in the evaporator100F may be similarly applied also to the evaporator100B (FIGS. 10 to 12) described in the foregoing third embodiment. In addition, such a method may be similarly applied also to the evaporator100D (FIG. 14) and the evaporator100E (FIG. 15) described in the foregoing fifth and sixth embodiments.

Eighth Embodiment

FIG. 17is a diagram of assistance in explaining an example of an evaporator according to an eighth embodiment.FIG. 17schematically illustrates a fragmentary sectional view of the example of the evaporator.

In an evaporator100G illustrated inFIG. 17, a liquid phase refrigerant200supplied along an outer surface110dof a container110is circulated through an inside flow passage161from a lower portion to an upper portion of the container110, and is returned and circulated through an outside flow passage162from the upper portion to the lower portion. The liquid phase refrigerant200circulated through the flow passage162is discharged from a discharging unit170. The evaporator100G is different from the evaporator100A described in the foregoing second embodiment in such a respect.

A heat absorbing unit130in which the liquid phase refrigerant200absorbs heat from an external heat generating body300is provided to the lower portion of the container110(lower layer portion of the liquid phase refrigerant200in a storage part140). Therefore, the lower layer portion of the liquid phase refrigerant200in the storage part140, the heat absorbing unit130being disposed in the lower layer portion, is raised in temperature easily and boils easily as compared with an upper layer portion of the liquid phase refrigerant200on a space110cside. That is, a gaseous phase refrigerant210occurs easily in the lower layer portion of the liquid phase refrigerant200stored in the storage part140.

In the evaporator100G, the liquid phase refrigerant200is circulated through the inside flow passage161of a supplying unit160along the outer surface110dfrom the lower portion to the upper portion of the container110. While thus circulated from the lower portion to the upper portion, the liquid phase refrigerant200is made to exchange heat with an inner part110a, and is consequently increased in temperature. Therefore, in the evaporator100G, the closer a part of the outer surface110dis to the lower layer portion of the liquid phase refrigerant200in the storage part140, the gaseous phase refrigerant210occurring easily in the lower layer portion of the liquid phase refrigerant200, the lower the temperature of the liquid phase refrigerant200circulated along the part becomes. The evaporator100G may thereby quickly condense the gaseous phase refrigerant210generated by heat absorption in the heat absorbing unit130(for example, condense the gaseous phase refrigerant210in the liquid phase refrigerant200), and thus return the gaseous phase refrigerant210to the liquid phase refrigerant200.

The evaporator100G, also, may suppress the amount of discharge of the gaseous phase refrigerant210to the outside while increasing the amount of generation of the gaseous phase refrigerant210due to heat absorption. Thus, stable pump circulation may be realized while a high cooling capacity of the evaporator100G is realized.

Incidentally, a method of circulating the liquid phase refrigerant200along the outer surface110dfrom the lower portion to the upper portion of the container110as in the evaporator100G may be similarly applied also to the evaporator100B (FIGS. 10 to 12) described in the foregoing third embodiment. In addition, such a method may be similarly applied also to the evaporator100D (FIG. 14) and the evaporator100E (FIG. 15) described in the foregoing fifth and sixth embodiments.

Ninth Embodiment

FIG. 18is a diagram of assistance in explaining an example of an evaporator according to a ninth embodiment.FIG. 18schematically illustrates a fragmentary sectional view of the example of the evaporator.

In an evaporator100H illustrated inFIG. 18, an inlet160bof a supplying unit160that supplies a liquid phase refrigerant200along an outer surface110dof a container110is provided to a lower portion of the container110, and an outlet170bof a discharging unit170that discharges the liquid phase refrigerant200is provided to an upper portion of the container110. In the evaporator100H, the liquid phase refrigerant200is supplied from the lower portion of the container110, circulated toward the upper portion, and discharged from the upper portion of the container110. The evaporator100H is different from the evaporator100A described in the foregoing second embodiment in such a respect.

A heat absorbing unit130in which the liquid phase refrigerant200absorbs heat from an external heat generating body300is provided to the lower portion of the container110(lower layer portion of the liquid phase refrigerant200in the storage part140). Therefore, the lower layer portion of the liquid phase refrigerant200in the storage part140, the heat absorbing unit130being disposed in the lower layer portion, is raised in temperature easily and boils easily as compared with the upper layer portion of the liquid phase refrigerant200on the space110cside. That is, the gaseous phase refrigerant210occurs easily in the lower layer portion of the liquid phase refrigerant200stored in the storage part140.

In the evaporator100H, the supplying unit160circulates the liquid phase refrigerant200along the outer surface110dfrom the lower portion to the upper portion of the container110. While thus circulated from the lower portion to the upper portion, the liquid phase refrigerant200is made to exchange heat with the inner part110a, and is consequently increased in temperature. Therefore, in the evaporator100H, the closer a part of the outer surface110dis to the lower layer portion of the liquid phase refrigerant200in the storage part140, the gaseous phase refrigerant210occurring easily in the lower layer portion of the liquid phase refrigerant200, the lower the temperature of the liquid phase refrigerant200circulated along the part becomes. The evaporator100H may thereby quickly condense the gaseous phase refrigerant210generated by heat absorption in the heat absorbing unit130(for example condense the gaseous phase refrigerant210in the liquid phase refrigerant200), and thus return the gaseous phase refrigerant210to the liquid phase refrigerant200.

Further, in the evaporator100H, the liquid phase refrigerant200circulated along the outer surface110dfrom the lower portion to the upper portion of the container110is directly discharged from the upper portion of the container110through the discharging unit170without being returned. Therefore, the liquid phase refrigerant200increased in temperature by heat exchange with the inner part110awhile circulated from the lower portion to the upper portion of the container110is not involved in an increase in the temperature of the following liquid phase refrigerant200circulated later. The liquid phase refrigerant200circulated along the outer surface110dfrom the lower portion to the upper portion of the container110may cool the inside of the container110, and condense the gaseous phase refrigerant210efficiently.

The evaporator100H, also, may suppress the amount of discharge of the gaseous phase refrigerant210to the outside while increasing the amount of generation of the gaseous phase refrigerant210due to heat absorption. Thus, stable pump circulation may be realized while a high cooling capacity of the evaporator100H is realized.

Incidentally, a method of circulating the liquid phase refrigerant200along the outer surface110dfrom the lower portion to the upper portion of the container110as in the evaporator100H may be similarly applied also to the evaporator100B (FIGS. 10 to 12) described in the foregoing third embodiment. In addition, such a method may be similarly applied also to the evaporator100D (FIG. 14) and the evaporator100E (FIG. 15) described in the foregoing fifth and sixth embodiments.

Tenth Embodiment

The evaporators10A,10B,100A,100B,100C,100D,100E,100F,100G, and100H described in the foregoing first to ninth embodiments and the like may be used in a cooling system.

FIG. 19is a diagram of assistance in explaining an example of a cooling system according to a tenth embodiment.

FIG. 19illustrates, as an example, a cooling system1000using the evaporator100A as described in the foregoing second embodiment. The cooling system1000illustrated inFIG. 19includes the evaporator100A, a radiator400, and a pump500. The evaporator100A and the radiator400are coupled to each other by a pipe610. The radiator400and the pump500are coupled to each other by a pipe620. The pump500and the evaporator100A are coupled to each other by a pipe630. The evaporator100A, the radiator400, and the pump500as well as the pipe610, the pipe620, and the pipe630form a closed circuit of the cooling system1000. A liquid phase refrigerant200is filled in a decompressed state into the closed circuit of such a cooling system1000.

The evaporator100A is thermally coupled directly or indirectly to an external heat generating body300such as an electronic device or the like to be cooled by the cooling system1000. The evaporator100A absorbs heat transmitted from the heat generating body300by using the vaporization phenomenon of the internal liquid phase refrigerant200, and thereby cools the heat generating body300. Through the pipe610, the radiator400takes in the liquid phase refrigerant200discharged from the evaporator100A or the liquid phase refrigerant200including a gaseous phase refrigerant210. The radiator400radiates the heat of the taken-in liquid phase refrigerant200or the liquid phase refrigerant200including the gaseous phase refrigerant210to the outside by using outside air, and thereby lowers the temperature of the liquid phase refrigerant200. When the gaseous phase refrigerant210is included, the radiator400condenses the gaseous phase refrigerant210and lowers the temperature of the liquid phase refrigerant200. The pump500takes in the liquid phase refrigerant200condensed or lowered in temperature by the radiator400through the pipe620, and feeds the liquid phase refrigerant200to the evaporator100A through the pipe630. The evaporator100A absorbs heat from the heat generating body300(cools the heat generating body300) by using the liquid phase refrigerant200fed from the pump500through the pipe630. The cooling system1000is an example of a circulation type cooling system that thus utilizes the vaporization phenomenon of the liquid phase refrigerant200.

In the evaporator100A, as described above, the liquid phase refrigerant200at a relatively low temperature, the liquid phase refrigerant200being fed from the pump500coupled to the radiator400, is supplied to the inner part110aof the container110by the supplying unit120, and stored in the storage part140. The liquid phase refrigerant200in the storage part140absorbs the heat of the heat generating body300in the heat absorbing unit130. The liquid phase refrigerant200including the gaseous phase refrigerant210generated by the boiling of the liquid phase refrigerant200due to the heat absorption moves toward the inner surface110bof the container110while guided by the guide180, and further moves upward along the inner surface110b. In the evaporator100A, the supplying unit160circulates the liquid phase refrigerant200at a relatively low temperature along the outer surface110dof the container110. Thus, the container110and the fin190are cooled, and the generated gaseous phase refrigerant210is cooled and condensed within the evaporator100A and stored in the storage part140. Incidentally, not all of the generated gaseous phase refrigerant210necessarily needs to be condensed. The liquid phase refrigerant200or the liquid phase refrigerant200including the gaseous phase refrigerant210in the storage part140is discharged to the outside of the evaporator100A through the discharging unit150, and fed to the radiator400through the pipe610. Then, the liquid phase refrigerant200condensed and lowered in temperature by the heat radiation of the radiator400is taken into the pump500through the pipe620, and fed to the supplying unit120and the supplying unit160of the evaporator100A again from the pump500through the pipe630.

In the evaporator100A, the amount of discharge of the gaseous phase refrigerant210is suppressed by the function of condensing the gaseous phase refrigerant210by using the liquid phase refrigerant200supplied along the outer surface110dof the container110by the supplying unit160. The occurrence of biting of the gaseous phase refrigerant210by the pump500is thereby suppressed, so that the pump500circulates the liquid phase refrigerant200stably. Further, because the liquid phase refrigerant200is thus circulated stably, a condition under which the boiling of the liquid phase refrigerant200occurs easily may be used, and the cooling capacity of the evaporator100A is thereby enhanced. The cooling system1000is realized which includes the evaporator100A having a high cooling capacity and in which the pump500circulates the liquid phase refrigerant200stably.

The cooling system1000using the evaporator100A as described in the foregoing second embodiment has been illustrated here. In addition, cooling systems are similarly realized which use the evaporators10A,10B,100B,100C,100D,100E,100F,100G, and100H as described in the foregoing first and third to ninth embodiments and the like.

Eleventh Embodiment

The cooling system1000as described in the foregoing tenth embodiment and the like may be applied to an electronic apparatus.

FIG. 20is a diagram of assistance in explaining an example of an electronic apparatus according to an eleventh embodiment.

FIG. 20illustrates, as an example, an electronic apparatus2000using the cooling system1000as described in the foregoing tenth embodiment. The electronic apparatus2000illustrated inFIG. 20includes the cooling system1000and an electronic device300athat is a heat generating body to be cooled by the cooling system1000and is thermally coupled to the cooling system1000. The cooling system1000and the electronic device300athus thermally coupled to each other are, for example, incorporated into (built into) a casing of the electronic apparatus2000. Alternatively, the cooling system1000and the electronic device300athermally coupled to each other are incorporated in a slot, rack, or the like of the electronic apparatus2000.

In the evaporator100A used in the cooling system1000, the amount of discharge of the gaseous phase refrigerant210is suppressed by the function of condensing the gaseous phase refrigerant210by using the liquid phase refrigerant200supplied along the outer surface110dof the container110by the supplying unit160. The occurrence of biting of the gaseous phase refrigerant210by the pump500is thereby suppressed, so that the pump500circulates the liquid phase refrigerant200stably. Further, because the liquid phase refrigerant200is thus circulated stably, a condition under which the boiling of the liquid phase refrigerant200occurs easily may be used, and the cooling capacity of the evaporator100A is thereby enhanced. The cooling system1000is realized which includes the evaporator100A having a high cooling capacity and in which the pump500circulates the liquid phase refrigerant200stably. In the electronic apparatus2000, because such a cooling system1000is used, the electronic device300ais cooled efficiently and stably, and overheating of the electronic device300aand damage and performance degradation in the electronic device300adue to the overheating are suppressed. The electronic apparatus2000excellent in performance and reliability is thereby realized.

The electronic apparatus2000using the cooling system1000as described in the foregoing tenth embodiment has been illustrated here. In addition, electronic apparatuses are similarly realized in which cooling systems using the evaporators10A,10B,100B,100C,100D,100E,100F,100G, and100H as described in the foregoing first and third to ninth embodiments and the like are thermally coupled to the electronic device300a.