Heat exchange device and heat exchange method

Abstract

A heat exchange device (NS) includes a container (YK) in which a gas (KT), as well as a liquid (ET) having a solvent (YB) and a solute (YS), are sealed, the solute (YS) affecting surface-activating properties at a surface where the liquid (ET) makes contact with the gas (KT), and the liquid (ET) being such that the higher the concentration of the solute (YS) is, the lower the surface tension of the liquid (ET) becomes. A high-temperature region (KR) of the container (YK) is at a temperature below the boiling point of the solvent (YB) and the boiling point of the solute (YS), while a low-temperature region (TR) of the container (YK) is at a temperature below the solidification point of the solvent (YB).

Description

Heat exchange device and heat exchange method

[0001] The present disclosure relates to a heat exchange device and a heat exchange method.

[0002] In a conventional two-phase heat pipe, for example, the heat pipe-type heat transfer device described in Patent Document 1 is used. In the two-phase heat pipe, the alcohol evaporates earlier than the water in the high temperature region, i.e., becomes gas earlier, whereas in the low temperature region, the alcohol condenses earlier than the water, i.e., becomes liquid earlier.

[0003] Patent No. 3416731

[0004] However, in the two-phase heat pipe, the alcohol undergoes a phase transition between gas and liquid, as described above, and therefore the heat pipe needs to be strong enough to withstand the pressure change inside the heat pipe caused by the phase transition.

[0005] An object of the present disclosure is to provide a heat exchange device and a heat exchange method including a container that does not need to have the strength to withstand changes in internal pressure caused by the phase transition of a solute between gas and liquid.

[0006] The 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, the solute affecting the surface activity of the interface where the liquid comes into contact with the gas and the higher the concentration of the solute, the lower the surface tension of the liquid; the high temperature region of the container is at a temperature below the boiling point of the solvent and the boiling point of the solute, and the low temperature region of the container is at a temperature below the freezing point of the solvent.

[0007] According to the heat exchange device of the present disclosure, the container does not need to be strong enough to withstand changes in internal pressure caused by the solute transitioning between gas and liquid phases.

[0008] FIG. 1A shows the configuration of the heat exchanger NS of embodiment 1. FIG. 1B shows the operation (part 1) of the heat exchanger NS of embodiment 1. FIG. 1C shows the operation (part 2) of the heat exchanger NS of embodiment 1. FIG. 1D shows the operation (part 3) of the heat exchanger NS of embodiment 1. FIG. 2A shows the configuration of a heat exchanger NS of a comparative example. FIG. 2B shows the operation (part 1) of the heat exchanger NS of a comparative example. FIG. 2C shows the operation (part 2) of the heat exchanger NS of a comparative example. FIG. 2D shows the operation (part 3) of the heat exchanger NS of a comparative example. FIG. 3A shows the configuration of the heat exchanger NS of embodiment 2. FIG. 3B shows the operation (part 1) of the heat exchanger NS of embodiment 2. FIG. 3C shows the operation (part 2) of the heat exchanger NS of embodiment 2. FIG. 3D shows the operation (part 3) of the heat exchanger NS of embodiment 2. FIG. 4A shows the configuration of the heat exchanger NS of embodiment 3. Fig. 4B shows the operation (part 1) of the heat exchanger NS of embodiment 3. Fig. 4C shows the operation (part 2) of the heat exchanger NS of embodiment 3. Fig. 4D shows the operation (part 3) of the heat exchanger NS of embodiment 3.

[0009] An embodiment of a heat exchange device according to the present disclosure will be described.

[0010] First Embodiment A heat exchange device NS according to a first embodiment will be described.

[0011] <Basic Configuration of First Embodiment> The heat exchange device NS of the first embodiment can basically have the following configuration.

[0012] The system includes a container YK in which the liquid ET is sealed, the liquid ET having a gas KT, a solvent YB, and a solute YS, the solute YS affecting the surface activity of the interface where the liquid ET comes into contact with the gas KT, and the higher the concentration of the solute YS, the lower the surface tension of the liquid ET; a high temperature region KR of the container YK is a temperature below the boiling point of the solvent YB and the boiling point of the solute YS; and a low temperature region TR of the container YK is a temperature below the freezing point of the solvent YB.

[0013] <Configuration of First Embodiment> FIG. 1 shows the configuration and operation of a heat exchanger NS of the first embodiment.

[0014] The configuration of the heat exchanger NS of the first embodiment will be described with reference to FIG. 1A.

[0015] The heat exchange device NS of the first embodiment includes a container YK for heat exchange. The container YK contains a liquid ET and a gas KT for heat exchange. The liquid ET includes a solvent YB (e.g., water) and a solute YS (e.g., a surfactant (e.g., sodium dodecyl sulfate (SDS))).

[0016] The container YK and the liquid ET are roughly divided into a high temperature region KR, which is relatively high temperature, and a low temperature region TR, which is relatively low temperature.

[0017] The high temperature region KR is a temperature range below the boiling point of the solvent YB and below the boiling point of the solute YS.

[0018] The low temperature region TR is a temperature range that includes the freezing point of the solvent YB and exceeds the freezing point of the solute YS.

[0019] For example, assume that the solvent YB is water. Under this assumption, the high temperature region KR is below 100°C, which is the boiling point of water. On the other hand, the low temperature region TR is above 0°C, which is the freezing point of water. As the solute YS, it is desirable to use, for example, a surfactant whose precipitation temperature is below 0°C.

[0020] The gas KT is present inside the liquid ET, in other words, at a position closer to the center of the container YK. Due to the presence of the gas KT, an interface exists between the liquid ET and the gas KT, which are in contact with each other. As a result, capillary waves are generated.

[0021] <Operation of First Embodiment> The operation of the heat exchange device NS of the first embodiment will be described with reference to FIGS. 1B to 1D.

[0022] In the low temperature region TR, the solvent YB becomes solid KO, that is, solidifies, and the concentration of the solute YS (surfactant) increases.

[0023] On the other hand, in the high temperature region KR, the solvent YB melts from solid KO to liquid ET, thereby decreasing the concentration of the solute YS (surfactant).

[0024] Generally, the higher the concentration of the solute YS (surfactant), the lower the surface tension. Therefore, when comparing the interfacial tension in the high temperature region KR with the interfacial tension in the low temperature region TR, the interfacial tension in the high temperature region KR is relatively high, while the interfacial tension in the low temperature region TR is relatively low.

[0025] Comparative Example FIG. 2 shows the configuration and operation of a heat exchanger ns of a comparative example.

[0026] As described above, the heat exchanger ns of the comparative example is a conventional two-phase heat pipe, an example of which is the heat pipe type heat transfer device described in Patent Document 1. As described above, the heat exchanger ns uses, for example, a liquid et (e.g., water) and a surfactant (e.g., alcohol).

[0027] As described above, in the high temperature region kr, the surfactant evaporates, i.e., vaporizes, earlier than the liquid et, whereas in the low temperature region tr, the surfactant condenses, i.e., liquefies earlier than the liquid et.

[0028] In the heat exchanger ns of the comparative example, the alcohol undergoes a phase transition between gas kt and liquid et. Therefore, the heat pipe, i.e., the container yk, needs to have the strength to withstand the change in internal pressure of the container yk caused by the phase transition. <Effects of Embodiment 1> As described above, in the heat exchanger NS of embodiment 1, the liquid ET undergoes a phase transition between liquid ET and solid KO. Therefore, in the heat exchanger NS of embodiment 1, unlike the heat exchanger ns of the comparative example, the container YK does not need to have the strength to withstand the change in internal pressure caused by the phase transition of the alcohol between gas kt and liquid et.

[0029] In a heat exchanger NS according to a modification of the first embodiment, the solute YS (surfactant) may be, for example, a micelle or a vecillin, and the concentration distribution of the solute YS may be varied by changing the phase of the solute YS to an aggregate. In theory, it is desirable that the higher the temperature, the less likely it is that aggregates will form. However, in practice, the higher the temperature, the more likely it is that aggregates will form. However, it is expected that the same effect as that of the heat exchanger NS according to the first embodiment will be obtained.

[0030] Second Embodiment A heat exchange device NS according to a second embodiment will be described.

[0031] <Basic Configuration of Second Embodiment> The heat exchange device NS of the second embodiment may basically have the following configuration.

[0032] The system includes a container YK in which the liquid ET is sealed, the liquid ET having a gas KT, a solvent YB, and a solute YS, the solute YS affecting the surface activity of the interface where the liquid ET comes into contact with the gas KT, and the lower the concentration of the solute YS, the lower the surface tension of the liquid ET; a high temperature region KR of the container YK is a temperature below the boiling point of the solvent YB and the boiling point of the solute YS; and a low temperature region TR of the container YK is a temperature below the freezing point of the solute YS.

[0033] <Configuration of Second Embodiment> FIG. 3 shows the configuration and operation of a heat exchanger NS of a second embodiment.

[0034] The configuration of the heat exchanger NS of the second embodiment will be described with reference to FIG. 3A.

[0035] The heat exchange device NS of the second embodiment includes a container YK for heat exchange. The container YK contains a liquid ET and a gas KT for heat exchange. The liquid ET includes a solvent YB (e.g., water) as in the first embodiment. However, unlike the first embodiment, the liquid ET includes a solute YS (e.g., an electrolyte (e.g., sodium chloride (NaCl))).

[0036] <Operation of Second Embodiment> The operation of the heat exchange device NS of the second embodiment will be described with reference to FIGS. 3B to 3D.

[0037] Generally, there is a phenomenon in which the surface tension increases in accordance with the concentration of the solute YS (electrolyte) in water.

[0038] In the heat exchange device NS of embodiment 2, in line with the above phenomenon, the freezing point of the solute YS (electrolyte) is lower than the freezing point of the solvent YB, and as a result, in the low temperature region TR, the solute YS (electrolyte) freezes before the solvent YB.

[0039] In general, the "solubility," which is the upper limit of the amount of a solute (electrolyte) that can dissolve in a solvent, is temperature-dependent, and the higher the temperature, the higher the solubility. A solute (electrolyte) that is not completely dissolved in the solvent and solidifies does not contribute to the surface tension of the solvent.

[0040] In the heat exchange device NS of the second embodiment, the low temperature region TR is a temperature range in which the solute YS (electrolyte) does not completely dissolve and precipitates as a solid, while the high temperature region KR is a temperature range below the boiling point of the solvent YB and in which the solute YS (electrolyte) is sufficiently dissolved.

[0041] In the low temperature region TR, the solute YS (electrolyte) becomes solid, that is, solidifies into the solid electrolyte KD, and the concentration of the solute YS (electrolyte) decreases.

[0042] On the other hand, the "solubility" described above is higher in the high temperature region KR than in the low temperature region TR. As a result, the solute YS (electrolyte) dissolves from a solid to a liquid in the high temperature region KR. That is, the concentration of the solute YS (electrolyte) increases in the high temperature region KR.

[0043] Comparing the interfacial tension in the high temperature region KR with the interfacial tension in the low temperature region TR, as in embodiment 1, the interfacial tension in the high temperature region KR is relatively high, while the interfacial tension in the low temperature region TR is relatively low.

[0044] <Effects of Embodiment 2> As described above, in the heat exchanger NS of embodiment 2, similar to the heat exchanger NS of embodiment 1, the container YK differs from the container yk of the comparative example (shown in Figure 2) in that it does not need to be strong enough to withstand changes in internal pressure caused by the phase transition of alcohol between gas and liquid.

[0045] <Variations of Embodiments 1 and 2> In the heat exchange device NS of Embodiments 1 and 2, it is desirable that the inner diameter of the container YK (the radius in the short direction of the container YK) exceeds the minimum bubble radius (Laplace diameter) determined by the viscosity of the liquid ET so as to prevent the formation of a layer of only the gas KT.

[0046] Third Embodiment A heat exchange device NS according to a third embodiment will be described.

[0047] <Basic Configuration of Third Embodiment> The heat exchange device NS of the second embodiment may basically have the following configuration.

[0048] The container YK includes a sealed container YK containing a gas KT and a liquid ET having a solvent YB and a solute YS, and the container YK has a hydrophobic surface treatment applied to the inner wall of the container YK that is more concentrated in a low temperature region TR of the container YK than in a high temperature region KR of the container YK.

[0049] <Configuration and Operation of Third Embodiment> FIG. 4 shows the configuration and operation of a heat exchanger NS of a third embodiment.

[0050] The configuration of the heat exchanger NS of the third embodiment will be described with reference to FIG. 4A.

[0051] The heat exchange device NS of the third embodiment includes a container YK for heat exchange, similar to the first and second embodiments. The container YK contains a liquid ET and a gas KT for heat exchange, similar to the first and second embodiments.

[0052] In the heat exchanger NS of embodiment 3, in order to control the magnitude of the interfacial tension in the low temperature region TR and the high temperature region KR as in embodiments 1 and 2, instead of varying the concentration of the solute YS (e.g., surfactant) in the heat exchanger NS of embodiment 1 and varying the concentration of the solute YS (e.g., electrolyte) in the heat exchanger NS of embodiment 2, a distributed surface treatment HS is applied to the inside of the container YK, as shown in Figures 4B to 4D.

[0053] As the distributed surface treatment HS described above, for example, a hydrophobic surface treatment (e.g., a surface treatment using a silane compound) is applied to the inner wall surface of the container YK at a relatively high concentration in the low temperature region TR, while at a relatively low concentration in the high temperature region KR.

[0054] Due to the difference in the concentration of the surface treatment HS described above, the rate constant of the phase change in the low temperature region TR becomes relatively large, while the rate constant of the phase change in the high temperature region KR becomes relatively small.

[0055] <Effects of Embodiment 3> As described above, in the heat exchanger NS of embodiment 3, the hydrophobic surface treatment HS is distributed on the inner wall surface of the container YK, and therefore, similar to the heat exchanger NS of embodiments 1 and 2, unlike the container yk of the comparative example (shown in FIG. 2), it is possible to obtain the effect that the container does not need to be strong enough to withstand changes in internal pressure caused by the phase transition of alcohol between gas and liquid.

[0056] Fourth Embodiment A heat exchange device NS according to a fourth embodiment will be described.

[0057] <Basic Configuration of Fourth Embodiment> The heat exchange device NS of the fourth embodiment may basically have the following configuration.

[0058] The system includes a sealed container YK containing a gas KT and a liquid ET having a solvent YB and a solute YS, and by selectively irradiating the container YK with light, the surface tension of the liquid ET in a low temperature region TR of the container YK is reduced.

[0059] <Configuration of Fourth Embodiment> The configuration of the heat exchanger NS of the fourth embodiment is the same as that of the heat exchanger NS of the first embodiment, etc., except for the configuration of selectively irradiating light as described above.

[0060] <Operation of Embodiment 4> The heat exchanger NS of Embodiment 4 controls surface tension in the same manner as the heat exchanger NS of Embodiment 1, etc., but unlike the heat exchanger NS of Embodiment 1, etc., it controls surface tension by selectively irradiating light onto a substance whose surface tension changes when irradiated with light. Control using light is described, for example, in the literature "Manipulation of small particles at solid-liquid interface: light-driven diffusion osmosis."

[0061] An example of the above-mentioned substance is a substance whose surface tension changes as a result of cis-trans isomerization using light with a wavelength of 360 nm.

[0062] In the heat exchange device NS of the fourth embodiment, when the above-mentioned substance is irradiated with light of a wavelength absorbed by the double bond, the surface tension of the substance decreases. More specifically, by irradiating only the substance in the low temperature region TR with light, only the surface tension in the low temperature region TR decreases. On the other hand, by not irradiating the substance in the high temperature region KR with light, the surface tension in the high temperature region KR remains unchanged.

[0063] As described above, the heat exchanger NS of embodiment 4 uses a substance whose surface tension changes when irradiated with light, and selectively irradiates the substance with light to selectively change the surface tension. As a result, similar to the heat exchanger NS of embodiment 1, and unlike the heat exchanger ns of the comparative example, the container YK does not need to be strong enough to withstand the change in internal pressure caused by the phase transition of the alcohol between gas and liquid.

[0064] Fifth Embodiment A heat exchanger NS according to a fifth embodiment will be described.

[0065] <Basic Configuration of Fifth Embodiment> The heat exchange device NS of the fifth embodiment may basically have the following configuration.

[0066] The device includes a sealed container YK containing a gas KT and a liquid ET having a solvent YB and a solute YS, and the surface tension of the liquid ET in the low temperature region TR of the container YK is reduced by making the potential in the low temperature region TR of the container YK different from the potential in the high temperature region KR of the container YK.

[0067] <Configuration of embodiment 5> The configuration of the heat exchanger NS of embodiment 5 is the same as the configuration of the heat exchanger NS of embodiment 1, etc., except for the configuration in which the potential in the low temperature region TR of the container YK and the potential in the high temperature region KR are made different from each other.

[0068] <Operation of Fifth Embodiment> The heat exchanger NS of the fifth embodiment controls surface tension in the same manner as the heat exchanger NS of the first embodiment, etc., but unlike the heat exchanger NS of the first embodiment, etc., it uses electricity.

[0069] Generally, most liquids have an electric double layer structure on the surface, and a surface charge exists. When the potential is changed from the point where the surface charge becomes zero (point of zero charge: PZC), the surface tension decreases according to the electrocapillary curve.

[0070] The heat exchanger NS of the fifth embodiment has a structure in which a potential is applied to the liquid ET in the low temperature region TR, but no potential is applied to the liquid ET in the high temperature region KR, thereby making the magnitude of the surface tension in the low temperature region TR different from the magnitude of the surface tension in the high temperature region KR.

[0071] Generally, under the condition of natural potential where no external potential is applied, there exists a phenomenon in which the surface tension is in a high state near the apex of the capillary curve.

[0072] To utilize the above-mentioned phenomenon, the heat exchanger NS of the fifth embodiment has multiple electrodes installed from the high temperature region KR to the low temperature region TR. This makes it possible to apply a potential to the liquid ET. More specifically, by applying a potential to the low temperature region TR and not applying a potential to the high temperature region KR, a surface tension distribution is achieved in which the surface tension in the low temperature region TR is lower than the surface tension in the high temperature region KR.

[0073] Effect of Embodiment 5 As described above, in the heat exchanger NS of Embodiment 5, the surface tension is selectively changed by selectively applying a potential to the low temperature region TR and the high temperature region KR. As a result, in the heat exchanger NS of Embodiment 5, similar to the heat exchanger NS of Embodiment 1 and the like, and unlike the heat exchanger ns of the comparative example, it is possible to obtain an effect that the container YK does not need to be strong enough to withstand changes in internal pressure caused by the phase transition of the alcohol between a gas and a liquid.

[0074] The above-described embodiments may be combined with each other without departing from the spirit of the present disclosure, and components in each embodiment may be deleted or modified, or other components may be added, as appropriate.

[0075] <Supplementary Notes> Various aspects of the present disclosure are supplementary notes below.

[0076] <Supplementary Note 1> A heat exchange device comprising: a container for sealing a gas and a liquid having a solvent and a solute, the solute affecting the surface activity of an interface where the liquid comes into contact with the gas and the higher the concentration of the solute, the lower the surface tension of the liquid; a high temperature region of the container is at a temperature below the boiling point of the solvent and the boiling point of the solute; and a low temperature region of the container is at a temperature below the freezing point of the solvent.

[0077] <Supplementary Note 2> A heat exchange device comprising: a container for sealing a gas and a liquid having a solvent and a solute, the solute affecting the surface activity of the interface where the liquid comes into contact with the gas and the lower the concentration of the solute, the lower the surface tension of the liquid; a high temperature region of the container is at a temperature below the boiling point of the solvent and the boiling point of the solute; and a low temperature region of the container is at a temperature below the freezing point of the solute.

[0078] <Supplementary Note 3> The heat exchange device according to Supplementary Note 1 or Supplementary Note 2, wherein the container has a radius that is greater than a minimum bubble radius determined by the viscosity of the liquid.

[0079] <Supplementary Note 4> A heat exchange device comprising a container in which a gas and a liquid having a solvent and a solute are sealed, wherein the container has an inner wall subjected to a hydrophobic surface treatment that is thicker in a low temperature region of the container than in a high temperature region of the container.

[0080] <Supplementary Note 5> A heat exchange device comprising a container in which a gas and a liquid having a solvent and a solute are sealed, wherein the container is selectively irradiated with light to reduce the surface tension of the liquid in a low temperature region of the container.

[0081] <Supplementary Note 6> A heat exchange device comprising a container in which a gas and a liquid having a solvent and a solute are sealed, wherein a potential in a low-temperature region of the container is made different from a potential in a high-temperature region of the container, thereby reducing the surface tension of the liquid in the low-temperature region of the container.

[0082] <Supplementary Note 7> A heat exchange method for performing heat exchange using the heat exchange device according to Supplementary Note 1, 2, 4, 5, or 6.

[0083] The heat exchange device according to the present disclosure can be used to reduce the pressure resistance of a container.

[0084] NS heat exchanger, YK vessel, KR high temperature region, TR low temperature region, ET liquid, YB solvent, YS solute, KO solid, KT gas.

Claims

1. A container is provided in which a gas and a liquid having a solvent and a solute are sealed, the solute affecting the surface activity of an interface between the liquid and the gas, and the higher the concentration of the solute, the lower the surface tension of the liquid; the high temperature region of the vessel is at a temperature below the boiling point of the solvent and the boiling point of the solute; The cold region of the container is at a temperature below the freezing point of the solvent. heat exchange equipment.

2. A container is provided in which a gas and a liquid having a solvent and a solute are sealed, the solute affecting the surface activity of an interface where the liquid comes into contact with the gas, and the lower the concentration of the solute, the lower the surface tension of the liquid; the high temperature region of the vessel is at a temperature below the boiling point of the solvent and the boiling point of the solute; The cold region of the container is at a temperature below the freezing point of the solute. heat exchange equipment.

3. The container has a radius that is greater than a minimum bubble radius determined by the viscosity of the liquid. The heat exchange device according to claim 1 or 2.

4. A container containing a gas and a liquid having a solvent and a solute, selectively irradiating the container with light to reduce the surface tension of the liquid in cooler regions of the container; heat exchange equipment.

5. A heat exchange method comprising the step of: performing heat exchange using the heat exchange device according to claim 1 , 2 or 4 .