HEAT EXCHANGE DEVICE AND HEAT EXCHANGE METHOD

Description

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a Continuation of PCT International Application No. PCT/JP2023/002777 filed on Jan. 30, 2023, all of which is hereby expressly incorporated by reference into the present application.

TECHNICAL FIELD

The present disclosure relates to a heat exchange device and a heat exchange method.

BACKGROUND ART

In a conventional dual-phase heat pipe, an example of which is a heat-pipe-type heat transfer device described in Patent Literature 1, use a liquid (e.g. water) and a surfactant (e.g. an alcohol), for example. In the dual-phase heat pipe, the alcohol evaporates faster, that is, turns into a gas faster, as compared to water in a high temperature area; on the other hand, the alcohol condenses faster, that is, turns into a liquid faster, as compared to water in a low-temperature area.

CITATION LIST

Patent Literature

• Patent Literature 1: Japanese Patent No. 3416731

SUMMARY OF INVENTION

Technical Problem

However, in the dual-phase heat pipe described above, the alcohol described above undergoes phase transition between the gas and the liquid as described above. Accordingly, the heat pipe has needed to have strength that can withstand changes of the internal pressure of the heat pipe caused by the phase transition.

An object of the present disclosure is to provide a heat exchange device including a container, and a heat exchange method that eliminate the necessity for the container to have strength that can withstand changes of the internal pressure caused by phase transition of a solute between a gas and a liquid.

Solution to Problem

A heat exchange device according to the present disclosure includes: a container in which a gas, and a liquid having a solvent and a solute are sealed in, the solute influencing surface activity of an interface on which the liquid contacts the gas, and the liquid having surface tension that lowers as concentration of the solute increases, in which a high temperature area of the container is at a temperature lower than a boiling point of the solvent and a boiling point of the solute, and a low temperature area of the container is at a temperature lower than a solidification point of the solvent.

Advantageous Effects of Invention

The heat exchange device according to the present disclosure can achieve an advantageous effect of eliminating the necessity for the container to have strength that can withstand changes of the internal pressure caused by phase transition of the solute between the gas and the liquid.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1A depicts the configuration of a heat exchange device NS according to a first embodiment.

FIG. 1B depicts operation (No. 1) performed by the heat exchange device NS according to the first embodiment.

FIG. 1C depicts operation (No. 2) performed by the heat exchange device NS according to the first embodiment.

FIG. 1D depicts operation (No. 3) performed by the heat exchange device NS according to the first embodiment.

FIG. 2A depicts the configuration of a heat exchange device ns according to a comparative example.

FIG. 2B depicts operation (No. 1) performed by the heat exchange device ns according to the comparative example.

FIG. 2C depicts operation (No. 2) performed by the heat exchange device ns according to the comparative example.

FIG. 2D depicts operation (No. 3) performed by the heat exchange device ns according to the comparative example.

FIG. 3A depicts the configuration of a heat exchange device NS according to a second embodiment.

FIG. 3B depicts operation (No. 1) performed by the heat exchange device NS according to the second embodiment.

FIG. 3C depicts operation (No. 2) performed by the heat exchange device NS according to the second embodiment.

FIG. 3D depicts operation (No. 3) performed by the heat exchange device NS according to the second embodiment.

FIG. 4A depicts the configuration of a heat exchange device NS according to a third embodiment.

FIG. 4B depicts operation (No. 1) performed by the heat exchange device NS according to the third embodiment.

FIG. 4C depicts operation (No. 2) performed by the heat exchange device NS according to the third embodiment.

FIG. 4D depicts operation (No. 3) performed by the heat exchange device NS according to the third embodiment.

DESCRIPTION OF EMBODIMENTS

Embodiments of a heat exchange device according to the present disclosure are explained.

First Embodiment.

First Embodiment

A heat exchange device NS according to a first embodiment is explained.

Basic Configuration of First Embodiment

The heat exchange device NS according to the first embodiment basically can have the following configuration.

A container YK in which a gas KT, and a liquid ET having a solvent YB and a solute YS are sealed in is included, the solute YS influencing the surface activity of an interface on which the liquid ET contacts the gas KT, and the liquid ET having surface tension that lowers as the concentration of the solute YS increases, a high temperature area KR of the container YK is at a temperature lower than the boiling point of the solvent YB and the boiling point of the solute YS, and a low temperature area TR of the container YK is at a temperature lower than the solidification point of the solvent YB.

Configuration of First Embodiment

FIGS. 1A to 1D depict the configuration of and operation performed by the heat exchange device NS according to the first embodiment.

The configuration of the heat exchange device NS according to the first embodiment is explained with reference to FIG. 1A.

The heat exchange device NS according to the first embodiment includes the container YK for performing heat exchange. The container YK contains the liquid ET for heat exchange, and the gas KT. The liquid ET has the solvent YB (e.g. water) and the solute YS (e.g. a surfactant (e.g. sodium dodecyl sulfate (SDS: Sodium Dodecyl Sulfate))).

The container YK and the liquid ET are roughly classified into the high temperature area KR, which is at a relatively high temperature, and the low temperature area TR, which is at a relatively low temperature.

The high temperature area KR is at a temperature in a temperature range that is lower than the boiling point of the solvent YB and lower than the boiling point of the solute YS.

The low temperature area TR is at a temperature in a temperature range that includes the solidification point of the solvent YB and higher than the solidification point of the solute YS.

It is assumed, for example, that the solvent YB is water. On the basis of the assumption, the high temperature area KR is at a temperature lower than 100 degrees, which is the boiling point of water. On the other hand, the low temperature area TR is at a temperature equal to or greater than 0 degrees, which is the solidification point of water. It is desirable that, for example, a surfactant whose deposition temperature is lower than 0 degrees is used as the solute YS.

The gas KT is located inside the liquid ET; in other words, the gas KT is located at a position close to the center of the container YK. Due to the presence of the gas KT, there is an interface between the liquid ET and the gas KT that are in contact with each other. As a result, a capillary wave is generated.

Operation Performed in First Embodiment

Operation performed by the heat exchange device NS according to the first embodiment is explained with reference to FIG. 1B to FIG. 1D.

In the low temperature area TR, the solvent YB turns into a solid KO, that is, solidified, and this causes the concentration of the solute YS (surfactant) to rise.

On the other hand, in the high temperature area KR, the solvent YB which has been the solid KO melts, and turns into the liquid ET, and this causes the concentration of the solute YS (surfactant) to lower.

Typically, the higher the concentration of the solute YS (surfactant) is, the lower the surface tension is. Accordingly, when comparing the interfacial tension in the high temperature area KR and the interfacial tension in the low temperature area TR, the interfacial tension in the high temperature area KR is relatively high; on the other hand, the interfacial tension in the low temperature area TR is relatively low.

COMPARATIVE EXAMPLE

FIGS. 2A to 2D depict the configuration of and operation performed by a heat exchange device ns according to a comparative example.

As mentioned above, the heat exchange device ns according to the comparative example is a conventional dual-phase heat pipe, an example of which is a heat-pipe-type heat transfer device described in Patent Literature 1. In the heat exchange device ns, as mentioned above, for example, a liquid et (e.g. water) and a surfactant (e.g. an alcohol) are used.

As mentioned above, the surfactant evaporates faster, that is, vaporizes faster, as compared to the liquid et, in a high temperature area kr; on the other hand, the surfactant condenses faster, that is, liquefied faster, as compared to the liquid et, in a low temperature area tr.

In the heat exchange device ns according to the comparative example, the alcohol undergoes phase transition between a gas kt and the liquid et. Accordingly, the heat pipe, that is, a container yk, needs to have strength that can withstand changes of the internal pressure of the container yk caused by the phase transition.

Advantageous Effects of First Embodiment

As mentioned above, in the heat exchange device NS according to the first embodiment, the liquid ET undergoes phase transition between the liquid ET and the solid KO. Accordingly, the heat exchange device NS according to the first embodiment can achieve an advantageous effect of eliminating the necessity for the container YK to have strength that can withstand changes of the internal pressure caused by phase transition of the alcohol between the gas kt and the liquid et, unlike the heat exchange device ns according to the comparative example.

Modification Example of First Embodiment

In a heat exchange device NS according to a modification example, for example, a micelle or a vesicle is used as the solute YS (surfactant) described above, and the concentration distribution of the solute YS may be made different by a phase change to an aggregate. While theoretically it is desirable that the higher the temperature, the less likely an aggregate is generated, but actually the higher the temperature, the more likely an aggregate is generated typically, it is expected that advantageous effects similar to advantageous effects of the heat exchange device NS according to the first embodiment mentioned above can be achieved.

Second Embodiment.

Second Embodiment

A heat exchange device NS according to a second embodiment is explained.

Basic Configuration of Second Embodiment

The heat exchange device NS according to the second embodiment basically can have the following configuration.

A container YK in which a gas KT, and a liquid ET having a solvent YB and a solute YS are sealed in is included, the solute YS influencing the surface activity of an interface on which the liquid ET contacts the gas KT, and the liquid ET having surface tension that lowers as the concentration of the solute YS decreases, a high temperature area KR of the container YK is at a temperature lower than the boiling point of the solvent YB and the boiling point of the solute YS, and a low temperature area TR of the container YK is at a temperature lower than the solidification point of the solute YS.

Configuration of Second Embodiment

FIGS. 3A to 3D depict the configuration of and operation performed by the heat exchange device NS according to the second embodiment.

The configuration of the heat exchange device NS according to the second embodiment is explained with reference to FIG. 3A.

The heat exchange device NS according to the second embodiment includes the container YK for performing heat exchange. The container YK contains the liquid ET for heat exchange, and the gas KT. Similarly to the first embodiment, the liquid ET has the solvent YB (e.g. water). On the other hand, unlike the first embodiment, the liquid ET has the solute YS (e.g. an electrolyte (e.g. sodium chloride (NaCl)).

Operation Performed in Second Embodiment

Operation performed by the heat exchange device NS according to the second embodiment is explained with reference to FIG. 3B to FIG. 3D.

Typically, there is a phenomenon in which the surface tension of water rises depending on the concentration of the solute YS (electrolyte) in water.

In the heat exchange device NS according to the second embodiment, on the basis of the phenomenon, the solidification point of the solute YS (electrolyte) is lower than the solidification point of the solvent YB, and this makes the solute YS (electrolyte) solidify faster than the solvent YB in the low temperature area TR.

Typically, the “solubility” of a solute (electrolyte), which is the upper limit of a dissolvable amount of the solute in a solvent, is temperature-dependent, and increases as the temperature rises. A solute (electrolyte) remaining solidified as a solid without being fully dissolved in a solvent does not contribute to the surface tension described above of the solvent.

In the heat exchange device NS according to the second embodiment, the low temperature area TR is at a temperature in a temperature range that makes the solute YS (electrolyte) remain partially undissolved, and makes the remaining solute YS deposited as a solid. On the other hand, the high temperature area KR is at a temperature range that is lower than the boiling point of the solvent YB, and makes the solute YS (electrolyte) fully dissolved sufficiently.

In the low temperature area TR, solidification of the solute YS (electrolyte) occurs, that is, solidification of the solute YS to a solid electrolyte KD occurs, and the concentration of the solute YS (electrolyte) lowers.

On the other hand, the “solubility” described above is higher in the high temperature area KR as compared to the low temperature area TR. Thereby, in the high temperature area KR, the solute YS (electrolyte), which has been a solid, dissolves, and turns into a liquid. That is, in the high temperature area KR, the concentration of the solute YS (electrolyte) rises.

When comparing the interfacial tension in the high temperature area KR and the interfacial tension in the low temperature area TR, similarly to the first embodiment, the interfacial tension in the high temperature area KR is relatively high; on the other hand, the interfacial tension in the low temperature area TR is relatively low.

Advantageous Effects of Second Embodiment

As mentioned above, similarly to the heat exchange device NS according to the first embodiment, the heat exchange device NS according to the second embodiment can achieve an advantageous effect of eliminating the necessity for the container YK to have strength that can withstand changes of the internal pressure caused by phase transition of the alcohol between the gas and the liquid, unlike the container yk according to the comparative example (depicted in FIG. 2).

Modification Example of First And Second Embodiments

It is desirable that, in the heat exchange device NS according to the first and second embodiments, the internal diameter of the container YK (the radius of the container YK in the shorter-side direction) is greater than a minimum bubble radius (Laplace diameter) decided depending on the viscosity of the liquid ET so as to prevent generation of a layer including only the gas KT.

Third Embodiment.

Third Embodiment

A heat exchange device NS according to a third embodiment is explained.

Basic Configuration of Third Embodiment

The heat exchange device NS according to the third embodiment basically can have the following configuration.

A container YK in which a gas KT, and a liquid ET having a solvent YB and a solute YS are sealed in is included, and in the container YK, the inner wall of the container YK has been subjected to a hydrophobic surface treatment at higher concentration in a low temperature area TR of the container YK as compared to a high temperature area KR of the container YK.

Configuration According to and Operation Performed in Third Embodiment

FIGS. 4A to 4D depict the configuration of and operation performed by the heat exchange device NS according to the third embodiment.

The configuration of the heat exchange device NS according to the third embodiment is explained with reference to FIG. 4A.

Similarly to the first embodiment and the second embodiment, the heat exchange device NS according to the third embodiment includes the container YK for performing heat exchange. Similarly to the first embodiment and the second embodiment, the container YK contains the liquid ET for heat exchange, and the gas KT.

In the heat exchange device NS according to the third embodiment, as depicted in FIG. 4B to FIG. 4D, the inside of the container YK has been subjected to a distributive surface treatment HS so as to control, as in the first embodiment and the second embodiment, the magnitude of the interfacial tension in the low temperature area TR and the magnitude of the interfacial tension in the high temperature area KR, instead of making the concentration of the solute YS (e.g. a surfactant) in the heat exchange device NS different as in the first embodiment, and instead of making the concentration of the solute YS (e.g. an electrolyte) in the heat exchange device NS different as in the second embodiment.

As the distributive surface treatment HS described above, for example, the inner wall surface of the container YK has been subjected to a hydrophobic surface treatment (e.g. a surface treatment using a silane compound) at relatively high concentration in the low temperature area TR; on the other hand, the inner wall surface of the container YK has been subjected to the hydrophobic surface treatment at relatively low concentration in the high temperature area KR.

Due to the difference in levels of the concentration of the surface treatment HS described above, the rate constant of a phase change in the low temperature area TR increases relatively; on the other hand, the rate constant of a phase change in the high temperature area KR decreases relatively.

Advantageous Effects of Third Embodiment

As mentioned above, since the inner wall surface of the container YK is subjected to the distributive hydrophobic surface treatment HS, the heat exchange device NS according to the third embodiment can achieve an advantageous effect of eliminating the necessity for having strength that can withstand changes of the internal pressure caused by phase transition of the alcohol between the gas and the liquid, similarly to the heat exchange device NS according to the first embodiment and the second embodiment, unlike the container yk according to the comparative example (depicted in FIG. 2).

Fourth Embodiment.

Fourth Embodiment

A heat exchange device NS according to a fourth embodiment is explained.

Basic Configuration of Fourth Embodiment

The heat exchange device NS according to the fourth embodiment basically can have the following configuration.

A container YK in which a gas KT, and a liquid ET having a solvent YB and a solute YS are sealed in is included, and the container YK is selectively irradiated with light, thereby lowering the surface tension of the liquid ET in a low temperature area TR of the container YK.

Configuration According to Fourth Embodiment

The configuration of the heat exchange device NS according to the fourth embodiment is similar to that of the heat exchange device NS according to the first embodiment or the like, except for the configuration related to selective irradiation with light described above.

Operation Performed in Fourth Embodiment

In the heat exchange device NS according to the fourth embodiment, control of surface tension similar to that for the heat exchange device NS according to the first embodiment or the like is performed by selectively irradiating, with light, a substance whose surface tension changes upon receiving radiated light, unlike the heat exchange device NS according to the first embodiment or the like. For example, control using light is described in the document, “Manipulation of small particles at solid liquid interface: light driven diffusioosmosis.”

Examples of the substance described above include a substance whose surface tension changes due to cis-trans isomerization using light whose wavelength is 360 nm.

In the heat exchange device NS according to the fourth embodiment, the surface tension of the substance described above lowers when the substance is irradiated with light with a wavelength to be absorbed at double bonds. More specifically, by irradiating only the substance in the low temperature area TR with light, only the surface tension in the low temperature area TR lowers. On the other hand, without irradiating the substance in a high temperature area KR with light, the surface tension in the high temperature area KR remains unchanged.

As mentioned above, in the heat exchange device NS according to the fourth embodiment, the substance whose surface tension changes by receiving radiated light is used, and the substance is selectively irradiated with light, thereby selectively changing the surface tension. Thereby, similarly to the heat exchange device NS according to the first embodiment or the like, it is possible to achieve an advantageous effect of eliminating the necessity for the container YK to have strength that can withstand changes of the internal pressure caused by phase transition of the alcohol between the gas and the liquid, unlike the heat exchange device ns according to the comparative example.

Fifth Embodiment.

Fifth Embodiment

A heat exchange device NS according to a fifth embodiment is explained.

Basic Configuration of Fifth Embodiment

The heat exchange device NS according to the fifth embodiment basically can have the following configuration.

A container YK in which a gas KT, and a liquid ET having a solvent YB and a solute YS are sealed in is included, and the potential in a low temperature area TR of the container YK and the potential in a high temperature area KR of the container YK are made different from each other, thereby lowering the surface tension of the liquid ET in the low temperature area TR of the container YK.

Configuration According to Fifth Embodiment

The configuration of the heat exchange device NS according to the fifth embodiment is similar to the configuration of the heat exchange device NS according to the first embodiment or the like except for the configuration related to the potential in the low temperature area TR of the container YK and the potential in the high temperature area KR of the container YK that are made different from each other.

Operation Performed in Fifth Embodiment

In the heat exchange device NS according to the fifth embodiment, control of surface tension similar to that of the heat exchange device NS according to the first embodiment or the like is performed using electricity unlike the heat exchange device NS according to the first embodiment or the like.

Typically, many types of liquid have surface electrical double layer structures, and there is surface charge therein. By changing a potential with a potential (point of zero charge: PZC (Point of Zero Charge)) at which the surface charge is zero as the base point, the surface tension lowers along an electrocapillary curve.

The heat exchange device NS according to the fifth embodiment has a structure in which a potential is applied to the liquid ET in the low temperature area TR, and, on the other hand, a potential is not applied to the liquid ET in the high temperature area KR. Thereby, the magnitude of the surface tension in the low temperature area TR and the magnitude of the surface tension in the high temperature area KR are made different from each other.

Typically, there is a phenomenon in which, under a condition with a natural potential in which a potential is not applied externally, a capillary curve represents high surface tension near the vertex.

In order to use the phenomenon described above, in the heat exchange device NS according to the fifth embodiment, a plurality of electrodes are installed from the high temperature area KR to the low temperature area TR. It is made possible thereby to apply potentials to the liquid ET. More specifically, by applying a potential to the low temperature area TR, and, on the other hand, not applying a potential to the high temperature area KR, a surface tension distribution in which the surface tension in the low temperature area TR is lower than the surface tension in the high temperature area KR is achieved.

Advantageous Effects of Fifth Embodiment

As mentioned above, in the heat exchange device NS according to the fifth embodiment, the surface tension is changed selectively by selectively applying a potential to the low temperature area TR and the high temperature area KR. Thereby, similarly to the heat exchange device NS according to the first embodiment or the like, in the heat exchange device NS according to the fifth embodiment, it is possible to achieve an advantageous effect of eliminating the necessity for the container YK to have strength that can withstand changes of the internal pressure caused by phase transition of the alcohol between the gas and the liquid, unlike the heat exchange device ns according to the comparative example.

The embodiments mentioned above may be combined with each other, and also constituent elements in each embodiment may be deleted, be changed or have other additional constituent elements as appropriate, within the scope not departing from the gist of the present disclosure.

<Supplementary Notes>

Several aspects of the present disclosure are described below as supplementary notes.

<Supplementary Note 1>

A heat exchange device including:

• • a container in which a gas, and a liquid having a solvent and a solute are sealed in, the solute influencing surface activity of an interface on which the liquid contacts the gas, and the liquid having surface tension that lowers as concentration of the solute increases, in which
  • a high temperature area of the container is at a temperature lower than a boiling point of the solvent and a boiling point of the solute, and
  • a low temperature area of the container is at a temperature lower than a solidification point of the solvent.

<Supplementary Note 2>

A heat exchange device including:

• • a container in which a gas, and a liquid having a solvent and a solute are sealed in, the solute influencing surface activity of an interface on which the liquid contacts the gas, and the liquid having surface tension that lowers as concentration of the solute decreases, in which
  • a high temperature area of the container is at a temperature lower than a boiling point of the solvent and a boiling point of the solute, and
  • a low temperature area of the container is at a temperature lower than a solidification point of the solute.

<Supplementary Note 3>

The heat exchange device according to supplementary note 1 or supplementary note 2, in which the container has a radius greater than a minimum bubble radius determined depending on viscosity of the liquid.

<Supplementary Note 4>

A heat exchange device including:

• • a container in which a gas, and a liquid having a solvent and a solute are sealed in, in which
  • in the container, an inner wall of the container has been subjected to a hydrophobic surface treatment at higher concentration in a low temperature area of the container as compared to a high temperature area of the container.

<Supplementary Note 5>

A heat exchange device including:

• • a container in which a gas, and a liquid having a solvent and a solute are sealed in, in which
  • the container is selectively irradiated with light, thereby lowering surface tension of the liquid in a low temperature area of the container.

<Supplementary Note 6>

A heat exchange device including:

• • a container in which a gas, and a liquid having a solvent and a solute are sealed in, in which
  • a potential in a low temperature area of the container and a potential in a high temperature area of the container are made different from each other, thereby lowering surface tension of the liquid in the low temperature area of the container.

<Supplementary Note 7>

A heat exchange method of performing heat exchange using the heat exchange device according to supplementary note 1, 2, 4, 5, or 6.

INDUSTRIAL APPLICABILITY

The heat exchange device according to the present disclosure can be used for reducing the pressure-withstandability of the container.

REFERENCE SIGNS LIST

• • NS: heat exchange device; YK: container; KR: high temperature area; TR: low temperature area; ET: liquid; YB: solvent; YS: solute; KO: solid; KT: gas