JP2015083882A - Accumulator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an accumulator capable of nucleating a supercooled heat storage medium as soon as possible and as surely as possible.SOLUTION: An accumulator 1 includes: a heat storage tank 3; a heat storage medium 4; an anode electrode 5; a cathode electrode 6; and voltage application means 12. The heat storage medium 4 having a supercooled state and this heat storage medium 4 is stored in the heat storage tank 3. The anode electrode 5 includes a nucleation start portion 7. This nucleation start portion 7 is formed out of a tapered protrusion. The anode electrode 5 is arranged in a state in which the nucleation start portion 7 is in contact with the heat storage medium 4. The cathode electrode 6 is arranged apart from the anode electrode 5 and in contact with the heat storage medium 4. The voltage application means 12 applies a voltage between the anode electrode 5 and the cathode electrode 6. The heat storage medium 4 in a liquid phase state after being supercooled is nucleated by application of the voltage from the voltage application means 12.

Description

  Embodiments described herein relate generally to a heat storage device.

  Using the supercooling of the heat storage material capable of phase change, heat is stored in this heat storage material in the supercooled state, and when the heat release is requested, the supercooling state is released and the heat storage material is fixed from the liquid phase state. 2. Description of the Related Art A heat storage device that changes a phase state and heats an object with latent heat released along with the phase state is known. In this heat storage device, in the nucleation operation for canceling the supercooling of the heat storage material, the copper electrode to which a voltage is applied in order to cause the nucleation has a V-shaped cross section that gradually becomes deeper from the peripheral surface to the end surface in the vicinity of the end surface. There has been proposed a method of providing a scratch composed of a plurality of grooves. By applying a voltage to the copper electrode, crystal nuclei are generated starting from the spot where the copper electrode is scratched, and the heat storage material can be nucleated.

  Canceling the supercooled state of the heat storage material that has been supercooled and in the liquid phase state to change the heat storage material from the liquid phase state to the solid phase state is referred to as “nucleation”. When the nucleation operation is started when the heat storage material is in the liquid phase, the heat storage material that is supercooled and in the liquid phase can be changed to the solid phase.

  In a heat storage device that uses a heat storage material with supercooling, when a voltage is applied to the electrode by a nucleation operation, if the probability of generating a crystal nucleus near the electrode is low, it takes a long time to generate the crystal nucleus. There is a problem that crystal nuclei are not generated even when a voltage is applied for a certain period of time.

  When the generation time of crystal nuclei (in other words, the time until nucleation is started) is long, the controllability of supercooling is lowered. That is, it takes a long time for the heat storage material in the liquid phase state to be released from the supercooled state after the voltage is applied for nucleation. For this reason, the latent heat stored in the heat storage material cannot be released immediately after the nucleation operation.

  When crystal nuclei are not generated regardless of voltage application and nucleation is not possible, control for canceling the supercooling of the heat storage material cannot be performed. That is, even after performing the nucleation operation, the heat storage material does not change to the solid phase but maintains the supercooled liquid phase. Since the heat storage material is not solidified in this way, the latent heat stored in the heat storage material cannot be released.

  For this reason, increasing the generation probability of crystal nuclei in the vicinity of an electrode to which a voltage is applied can contribute to improvement in controllability of supercooling and improvement in reliability for canceling supercooling. Therefore, development of a heat storage device that can solve these problems is desired.

  Embodiment is providing the thermal storage apparatus which can nucleate the supercooled thermal storage material quickly and reliably.

JP 2012-32130 A

  Embodiment is providing the thermal storage apparatus which can nucleate the supercooled thermal storage material quickly and reliably.

  In order to solve the above-described problem, the heat storage device of the embodiment includes a heat storage tank, a heat storage material, an anode electrode, a cathode electrode, and voltage application means. A heat storage material having supercooling is used, and this heat storage material is accommodated in a heat storage tank. The anode electrode has a nucleation starting point. This nucleation starting point portion is formed by a tapered protrusion. An anode electrode is arranged in a state where the nucleation starting point portion is in contact with the heat storage material. The cathode electrode is disposed away from the anode electrode and in contact with the heat storage material. The voltage applying means applies a voltage between the anode electrode and the cathode electrode. It is characterized in that the heat storage material in a liquid phase state that has been supercooled is nucleated by the application of voltage by the voltage application means.

It is a schematic diagram which shows the structure of the thermal storage apparatus which concerns on 1st Embodiment. It is a side view which expands and shows a part of anode electrode with which the thermal storage apparatus of FIG. 1 is provided. It is sectional drawing which expands and shows a part of nucleation origin part which the anode electrode of FIG. 2 has. FIG. 4 is a cross-sectional view corresponding to FIG. 3 showing a first mode of a nucleation starting point portion that can be formed on the anode electrode of FIG. 2. FIG. 4 is a cross-sectional view corresponding to FIG. 3 showing a second embodiment of the nucleation starting portion that can be formed on the anode electrode of FIG. 2. FIG. 4 is a cross-sectional view corresponding to FIG. 3 showing a third embodiment of a nucleation starting point portion that can be formed on the anode electrode of FIG. 2. It is a side part of the lower part of the anode electrode which shows the 4th aspect of the nucleation origin part which can be formed in the anode electrode of FIG. It is a graph which shows the result of having measured the nucleation start time of the various samples from which the shape of a nucleation origin part differs at the time of the initial 1 cycle, and the time of 50 cycles. It is a schematic diagram which shows the structure of the heat storage apparatus which concerns on 2nd Embodiment. It is a side view which expands and shows a part of anode electrode of 3rd Embodiment. It is sectional drawing along F11-F11 shown in FIG. It is a schematic diagram which expands and shows the front-end | tip part (A part) of the anode electrode shown in FIG. It is a side view which expands and shows a part of anode electrode of 4th Embodiment. It is a side view which expands and shows the groove | channel formed in the anode electrode shown in FIG. It is a side view which expands and shows a part of anode electrode of 5th Embodiment. FIG. 16 is a cross-sectional view taken along line F16-F16 of the anode electrode shown in FIG. It is a schematic diagram which expands and shows the front-end | tip part (B part) of the anode electrode shown in FIG.

(First embodiment)
Hereinafter, the heat storage device according to the first embodiment will be described in detail with reference to FIGS.

  As shown in the schematic diagram of FIG. 1 showing the configuration of the heat storage device, the heat storage device 1 includes a heat storage unit 2 and a control unit 11.

  The heat storage unit 2 includes a heat storage tank 3, a heat storage material 4, an anode electrode 5, and a cathode electrode 6.

  A heat storage material 4 is accommodated in the heat storage tank 3. As the heat storage material 4, a latent heat storage material (PCM; Phase change material) having supercooling is used. The heat storage material 4 has a characteristic of maintaining the liquid phase state without solidifying even when the temperature is lowered from the liquid phase state to be below the melting point. Such a heat storage material is referred to as a latent heat storage material or phase change heat storage material having supercooling.

  Examples of the heat storage material 4 include sodium acetate such as sodium acetate hydrate and sodium sulfate such as sodium sulfate hydrate. When the heat storage temperature is high, it is desirable to use sodium acetate hydrate. The general physical properties of sodium acetate hydrate are a melting point of 40 to 58 ° C., a latent heat of 100 to 264 kj / kg, and a specific heat of 1 to 4 kJ / kg / K.

  The anode electrode 5 is made of a conductive material for applying a positive voltage to the heat storage material 4. The anode electrode 5 has a nucleation starting point portion 7 in a part thereof. The nucleation starting point portion 7 is integrally provided on the peripheral surface of the round bar-shaped anode electrode body 5a in a spiral shape as shown in a side view showing, for example, an enlarged part of the anode electrode 5 in FIG. Yes.

  The anode electrode 5 is made of a conductive material for applying a positive voltage to the heat storage material 4. The anode electrode 5 has a nucleation starting point portion 7 in a part thereof. The nucleation starting point portion 7 is integrally provided on the peripheral surface of the round bar-shaped anode electrode body 5a in a spiral shape as shown in a side view showing, for example, an enlarged part of the anode electrode 5 in FIG. Yes.

  The nucleation starting point portion 7 is formed by a tapered projection, and as a specific example, as shown in FIG. The cross-sectional shape along the direction orthogonal to the extending direction of the spiral nucleation starting point portion 7 is a triangle as shown in the first embodiment of the nucleation starting point portion in FIG. 3, and the two oblique sides 7a and 7b of this triangle are The sandwiching angle θ is 90 ° or less. At the same time, the height h of the nucleation starting point portion 7 is in the range of 5 μm to 100 μm. Here, the height h of the nucleation starting point portion 7 is defined by the calculated average roughness Ra of JIS B0601-2001. That is, since h = Ra, the height h of the nucleation starting point portion 7 can be expressed by the value of the calculated average roughness Ra.

  The cross-sectional shape of the nucleation starting point portion 7 shown in FIG. 3 is an isosceles triangle with a sharp tip, but is not limited to this, and the tip portion of the nucleation starting point portion 7 has a distortion. Also good. As an example of such a shape, for example, the shape of the nucleation starting point part 7 shown in the sectional views of the nucleation starting point part second embodiment to the fourth embodiment of the anode electrode of FIGS. it can.

  That is, the nucleation starting point portion 7 formed by the tapered protrusion shown in FIG. 4 has a rounded tip surface 7c at the tip. In FIG. 4, the tip surface of the nucleation starting point portion 7 can be a tip surface made of a flat surface instead of the bent tip surface.

  The nucleation starting point portion 7 formed by the tapered protrusion shown in FIG. 5 has a recess 7d at the tip portion thereof. The nucleation starting point portion 7 formed by the tapered protrusion shown in FIG. 6 has a bent tip portion 7e.

  Further, the nucleation starting point portion 7 may have the shape shown in the side view showing the fifth mode of the nucleation starting point portion of the anode electrode in FIG.

  The nucleation starting point portion 7 shown in FIG. 7 is not formed on the side surface of the anode electrode body 5a as shown in FIGS. 3 to 6, but is formed at the lower end portion of the anode electrode body 5a. The nucleation starting point 7 has a conical shape. The angle θ of the nucleation starting point portion 7 shown in FIGS. 4 to 7 is preferably 90 ° or less.

  One or more nucleation starting point portions 7 are sufficient. For example, each of FIGS. 3 to 6 shows a case where the anode electrode 5 has one nucleation starting point portion 7 formed in a spiral shape. . FIG. 7 shows a case where the anode electrode 5 has one nucleation starting point portion 7 formed in a conical shape.

  In order to ensure the durability of the anode electrode 5 due to potential corrosion, it is preferable to provide a plurality of nucleation starting point portions 7. Incidentally, when a plurality of spiral nucleation starting point portions 7 are provided on the anode electrode 5, in each of FIGS. 3 to 6, the spiral shape is shifted by a predetermined pitch in the axial direction of the anode electrode body 5 a like a multi-thread screw. A plurality of nucleation starting point portions 7 may be formed.

  Further, the plurality of nucleation starting point portions 7 are not spiral, but are formed in an annular shape that continues around the circumference of the anode electrode main body 5a, and the positions of the nucleation starting point portions are shifted in the axial direction of the anode electrode main body 5a. It is also possible to provide a plurality of protrusions. Similarly, it is possible to project a plurality of nucleation starting points having a tapered shape with a triangular cross section protruding from the side surface of the anode electrode main body 5a while shifting the positions in the axial direction or the circumferential direction of the anode electrode main body 5a. .

When the shape of the nucleation starting point portion 7 is distorted as shown in FIGS. 4 to 6, the nucleation starting point portion 7 has a volume S and a height h satisfying the following conditions. Good.
0 <S ≦ (πh3) / 3
5μm ≦ h ≦ 100μm
Note that the height h of the nucleation starting point portion 7 can be defined by the calculated average roughness Ra of JIS as described above. Therefore, h = Ra.

  In the anode electrode 5 having the nucleation starting point portion 7 having the shape described above, the surface of the nucleation starting point portion 7 can be formed of a metal material different from the metal forming the anode electrode main body 5a. In this case, as will be described later, as the voltage applied to the anode electrode 5 in contact with the heat storage material 4 increases, the possibility of potential corrosion occurring at the nucleation starting point portion 7 increases. It is preferable to form the surface of the portion 7 with a metal material having high corrosion resistance. Examples of such a metal material include silver and gold.

  The anode electrode 5 having corrosion resistance is made of, for example, the anode electrode body 5a made of stainless steel, and the surface of the tapered protrusion (the base part of the nucleation starting point portion 7) integrally formed on the anode electrode body 5a It can be obtained by depositing gold or the like by sputtering to form a corrosion-resistant layer. Employing such an anode electrode can reduce the amount of gold or silver used compared to the case where the entire anode electrode 5 is made of silver or gold. For this reason, since the cost of the anode electrode 5 and by extension, the cost of the heat storage apparatus 1 can be reduced, it is preferable.

  As shown in FIG. 1, the anode electrode 5 is disposed, for example, so as to be in contact with the heat storage material 4 as a whole. Therefore, the nucleation starting point portion 7 is also in contact with the heat storage material 4.

  The cathode electrode 6 is used to apply a negative voltage to the heat storage material 4, and is formed of a conductive metal material such as stainless steel or silver. As shown in FIG. 1, the cathode electrode 6 is disposed away from the anode electrode 5, for example, in a state where the cathode electrode 6 is entirely in contact with the heat storage material 4. The cathode electrode 6 and the anode electrode 5 are, for example, arranged so as to extend in the vertical direction and be substantially parallel.

  The control unit 11 includes voltage application means 12 and control means 13. The control unit 11 forms a unit, for example, and is disposed on the outer surface of the heat storage tank 3, for example. In addition, while the control part 11 can be arrange | positioned away from the thermal storage tank 3, it is equipped with the thermal storage apparatus 1 of this embodiment, for example, the control system of an air conditioner, or an air conditioner and other household appliances It may be connected or incorporated in another system such as a network home appliance control system that controls the whole.

  The positive electrode of the voltage application means 12 is connected to the anode electrode 5 via the first power supply line 14, and the negative electrode of the voltage application means 12 is connected to the cathode electrode 6 via the second power supply line 15. . That is, the voltage applying means 12 is provided so that a voltage can be applied between the anode electrode 5 and the cathode electrode 6. A battery or a constant voltage power source or the like can be used for the voltage applying means 12.

  Although not shown, the control means 13 includes a memory, a calculation unit, an applied voltage controller, and the like. The memory of the control means 13 stores various data necessary for controlling the heat storage device 1. The application voltage controller of the control means 13 and the voltage application means 12 are electrically connected via a signal line 16.

  The heat storage device 1 having the above-described configuration can be provided in a heat pump type air conditioner (not shown) capable of heating operation by a known refrigeration cycle. In this case, the heat storage device 1 is disposed with the side wall of the heat storage tank 3 in contact with at least a part of the peripheral surface of the compressor so that heat exchange can be performed with the compressor of the air conditioner.

  Thereby, the heat storage material 4 in the heat storage tank 3 is heated so that it may become the temperature more than melting | fusing point of the heat storage material 4 with the compressor which becomes high temperature during the heating operation of the air conditioner in winter. In other words, during the operation of the air conditioner, the temperature of the heat storage material 4 is increased by the exhaust heat of the compressor. As a result, the heat storage material 4 is dissolved and becomes a liquid phase.

  If the state where the heating operation is stopped is maintained, the heat storage material 4 is lowered to a temperature below its melting point. As described above, the heat storage material 4 is formed of a substance that can be supercooled. For this reason, even if the temperature of the heat storage material 4 decreases from the liquid phase state to the melting point or lower, the heat storage material 4 maintains the liquid phase state without being solidified and is supercooled, and stores latent heat.

  When the heat storage material 4 is kept in a supercooled state, the control means 13 applies a voltage application operation by the voltage application means 12 so that a preset voltage is not applied between both electrodes (the anode electrode 5 and the cathode electrode 6). Control to stop. While the heat storage material 4 is maintained in the supercooled state by this control, the heat storage material 4 is stable in the supercooled liquid phase state, and the heat storage material 4 is not crystallized (nucleated). For this reason, the latent heat stored in the heat storage material 4 is not released.

  When a command for taking out the latent heat of the heat storage material 4 is given to the control means 13 from the outside, the control means 13 causes the voltage application means 12 to set an applied voltage, and this set voltage is applied to the voltage application means 12. And controlling to apply between both electrodes. The application in this case can be executed by continuously applying the set voltage for a certain period of time, or can be executed by applying the applied voltage in a pulsed manner in a plurality of times.

  As the voltage applied between both electrodes by the voltage applying means increases, the anode electrode 5 and the cathode electrode 6 in contact with the heat storage material 4 may be deteriorated by potential corrosion. For this reason, the voltage applied between both electrodes by the voltage application means 12 is the minimum necessary for releasing the supercooling of the heat storage material 4 in the liquid phase state (in other words, causing the heat storage material 4 to nucleate). It is preferable to use a voltage.

  When a predetermined voltage is applied between the anode electrode 5 and the cathode electrode 6 in contact with the heat storage material 4 made of sodium acetate hydrate, the surface of the nucleation starting point portion 7 is reduced at least at the silver anode electrode 5. A reaction occurs, a reduction reaction of water occurs on the cathode 6 side, and a current flows through the heat storage material 4.

  Nucleation of the heat storage material 4 is started from the nucleation starting point portion 7 of the anode electrode 5. When nucleation occurs, the supercooled heat storage material 4 undergoes a phase displacement from the liquid phase state to the solid phase state, thereby releasing latent heat. Since the released latent heat is supplied to the compressor of the air conditioner that has started the heating operation, the temperature of the compressor is quickly raised by the latent heat released from the heat storage material 4. Thereby, since the temperature of the refrigerant quickly rises, it is possible to shorten the time required until the hot air is blown out from the indoor unit of the air conditioner starting from the start of the heating operation.

The inventor examined the relationship between various samples of the anode electrode 5 having different shapes of the nucleation starting point portion 7 and the nucleation start time. Table 1 shows the conditions of the nucleation starting point portion, that is, the shape, the angle θ, and the height h (or depth h) of the samples A to J prepared for this investigation.

  In this investigation, sodium acetate hydrate was used for the heat storage material 4, and the anode electrode 5 and the cathode electrode 6 were both made of silver. The prepared samples A to J were used for the anode electrode 5 of the heat storage device shown in FIG. The protrusions (protrusions) formed on Sample A to Sample F are the nucleation starting point portion 7 having the shape shown in FIGS. 2 and 3, and this nucleation starting point portion 7 was formed by cutting the anode electrode. The recesses (dents) formed in the anode electrodes of Sample G to Sample J are grooves formed in a V shape so as to reduce the thickness of the anode electrode body. For this reason, the angle θ of the nucleation starting point in Sample G to Sample J is the angle of the V-shaped groove, and the height h of the nucleation starting point in the sample is the depth of the V-shaped groove. is there.

  Further, in this investigation, a constant voltage of 1.7 V was applied in a pulse waveform between both electrodes (the anode electrode 5 and the cathode electrode 6) in the heat storage device 1 in FIG. 1, and from the time when this application was started. The time until crystallization of the heat storage material 4 started was measured as the nucleation start time. When the nucleation start time passed 60 seconds, it was judged that crystallization was impossible (nucleation was impossible).

  At the same time, in this investigation, the initial nucleation start time in one cycle and the nucleation start time in 50 cycles were measured. Here, one cycle is a process until the heat storage material 4 is supercooled after the heat storage material 4 is crystallized to be in a solid phase and then the crystal is melted to make the heat storage material 4 in a liquid phase. Pointing. The initial one cycle is the first cycle in which the first measurement is executed, and 50 cycles means that the above process is repeated 50 times.

  FIG. 8 shows the results of measuring the relationship between Sample A to Sample J and the nucleation start time under the above conditions.

  From FIG. 8, it was confirmed that Sample B to Sample D had a significantly shorter nucleation start time than Sample A and Sample E to Sample J even in the case of the first cycle and after 50 cycles. . At the same time, in Samples A to E where the nucleation starting portion is formed of protrusions, crystallization (nucleation) of the heat storage material 4 was observed, whereas Sample F to Sample J where the nucleation starting portion was formed of a depression. Then, crystallization (nucleation) of the heat storage material 4 was not recognized.

  The reason why the nucleation starting point portion 7 formed of a tapered protrusion can contribute to the crystallization (nucleation) of the heat storage material 4 is that the voltage applied to the anode electrode 5 is concentrated on the nucleation starting point portion 7 and this nucleation starting point. It is presumed that the strong electric field formed between the portion 7 and the cathode 6 increases the certainty that crystal nuclei are generated in the vicinity of the nucleation starting point portion 7.

  According to the results shown in FIG. 8 and the conditions shown in Table 1, the tapered nucleation starting point portion 7 of the anode electrode 5 has an angle θ of 90 ° or less and a height h of 5 μm or more and 100 μm or less. It was confirmed that it is preferable to release the supercooled state of the heat storage material 4 and crystallize the heat storage material 4. Furthermore, from the results of Sample B to Sample D, it was confirmed that the height h of the nucleation starting portion 7 is preferably 12 μm or more and 25 μm in order to obtain a shorter nucleation start time.

  Therefore, as described above, the angle θ of the nucleation starting point portion 7 formed in a tapered shape is set to 0 ° <θ ≦ 90 °, and the height h of the nucleation starting point portion 7 is set to 5 μm ≦ h ≦ 100 μm. According to the heat storage device 1 of the first embodiment including the anode electrode 5, it is possible to nucleate the supercooled heat storage material 4 quickly and reliably.

  Further, as described above, in the heat storage device 1 of the first embodiment, the nucleation starting point portion 7 of the anode electrode 5 in contact with the heat storage material 4 increases the voltage applied between the anode electrode 5 and the cathode electrode 6. Therefore, there is a risk of deterioration due to potential corrosion. However, the nucleation starting point portion 7 of the anode electrode 5 is not a protrusion like an independent peak, but is provided in a single spiral shape.

  For this reason, it can be considered that the nucleation starting point portion 7 of the anode electrode 5 has substantially a plurality of locations facing the cathode electrode 6. Thereby, compared with the case where the said potential corrosion concentrates on one nucleation origin part, potential corrosion is disperse | distributed to the long nucleation origin part 7 whole. As a result, deterioration of the spiral nucleation starting point portion 7 due to potential corrosion is suppressed. Accordingly, it is possible to improve the durability as in the case where the anode electrode 5 is provided with a plurality of nucleation starting point portions 7.

(Second Embodiment)
FIG. 9 shows a second embodiment. The heat storage device of the second embodiment is the same as that of the first embodiment except for the following description. For this reason, about the structure which show | plays the same or same function as 1st Embodiment, the code | symbol same as 1st Embodiment is attached | subjected and the description is abbreviate | omitted.

  The second embodiment is different from the first embodiment in the configuration of the cathode electrode 6. That is, the cathode electrode 6 has a cylindrical shape such as a cylinder in which both ends in the axial direction are open. An anode electrode 5 is arranged at the center of the inside of the cathode electrode 6. In other words, the cathode electrode 6 is disposed so as to surround the anode electrode 5. In this case, it is preferable that the cathode electrode 6 be arranged such that the distance between the spiral nucleation starting point portion 7 and the inner peripheral surface of the cathode electrode 6 is substantially equal.

  According to the second embodiment including such a cathode electrode 6, the distance between the spiral nucleation starting point portion 7 and the inner peripheral surface of the cathode electrode 6 becomes substantially equal. For this reason, as a voltage is applied between the anode electrode 5 and the cathode electrode 6, the strength of the electric field formed between each part of the nucleation starting point portion 7 and the inner peripheral surface of the cathode electrode 6 is generated. Absent.

  On the other hand, in the configuration of the first embodiment, the distance between the cathode electrode 6 and the portion of the spiral nucleation starting point 7 facing the cathode electrode 6 is the following other portions and the cathode electrode 6. Shorter than the distance between. Here, the “other part” is a part of the nucleation starting point portion 7 that is located on the opposite side of the anode electrode body 5a and does not face the cathode electrode 6 with respect to the part. For this reason, the electric field formed when a voltage is applied between the two electrodes is stronger when the distance is relatively short and weak when the distance is long.

  As described above, according to the second embodiment, the distance between each portion of the nucleation starting point portion 7 of the anode electrode 5 and the inner peripheral surface of the cathode electrode 6 is substantially equal. Along with this, the nucleation of the supercooled heat storage material 4 can be promoted by a strong electric field formed between each part of the nucleation starting point portion 7 continuous in the circumferential direction of the anode electrode 5 and the cathode electrode 6. It is.

  The configurations other than those described above in the heat storage device 1 of the second embodiment are the same as those of the first embodiment, including the configuration not shown in FIG. Therefore, also in the second embodiment, the anode electrode 5 has the nucleation starting point portion 7 formed in a tapered shape, so that the supercooled heat storage material 4 can be nucleated quickly and reliably. .

  As described above, the example in which the nucleation starting point portion 7 is formed by cutting has been described. However, the manufacturing method of the nucleation starting point portion 7 is not limited thereto, and the nucleation starting point portion 7 is formed as in the following embodiment. It can also be formed by shearing or polishing.

(Third embodiment)
A third embodiment in which the nucleation starting member 7 is formed by shearing will be described with reference to FIGS.

  The convex nucleation starting point portion 7 is formed by crushing the rod-shaped anode electrode 5 in the direction indicated by the arrow in FIG. 10 using a nipper or the like so that the cut portion is stretched in the longitudinal direction of the anode electrode 5. . For example, when soft silver is used as the material of the anode electrode 5, elongation occurs in this way when shearing at low speed. For this reason, the cut surface is distorted and fine convex portions (nucleation start point portions 7) are formed at a plurality of locations as shown in FIG.

  As shown in FIG. 12, the angle θ between the oblique sides 20 a and 20 b of the tip of the substantially triangular nucleation starting point 7 (or the angle between the tangents 10 of the tip of the nucleation starting point 7) is, for example, The predetermined value is greater than 0 °, for example, 90 ° or less.

  The anode electrode 5 of the present embodiment can be formed by, for example, using a nipper and, for example, manually cutting a silver bar having a diameter of 2 mm at a low speed for about 3 seconds. Thereby, the nucleation origin part 7 can be easily formed with respect to the method of processing with a drill. When the nucleation performance of the anode electrode 5 thus prepared was evaluated, it was confirmed that nucleation occurred stably.

(Fourth embodiment)
A fourth embodiment will be described with reference to FIGS. In the fourth embodiment, similarly to the third embodiment, the convex nucleation starting member 7 is formed by shearing (pressing).

  In the fourth embodiment, by projecting a cross-shaped groove 21 with a cutter on the rod-shaped anode electrode 5, for example, convex portions (7a, 7b having an angle θ greater than 0 ° and 90 ° or less). ), That is, a convex nucleation starting portion 7 is formed. For example, when silver is used for the anode electrode 5, the groove 21 can be easily formed by press working because of the soft characteristic of silver. The angle of the cutter blade is set so that the angle θ sandwiched between the hypotenuses 20a and 20b of the nucleation starting point portion 7 (7a and 7b) is greater than 0 ° and 90 ° or less. The height h of the anode electrode 5 (depth of the groove 21) is preferably 5 μm or more and 100 μm or less.

  The anode electrode 5 of the present embodiment can be formed by, for example, processing (pressing) pressing a cutter blade having a blade width of 0.3 mm against a silver bar having a diameter of 2 mm. When the nucleation performance of the anode electrode 5 thus prepared was evaluated, it was confirmed that nucleation occurred stably from the nucleation origin 7 (7a, 7b).

  In addition to the projection formed in the present invention, the projection formed on a certain surface (in this embodiment, the outer peripheral surface of the rod-shaped anode electrode 5), as represented by the present embodiment, ( Flat projections) are also included.

(Fifth embodiment)
A fifth embodiment in which the nucleation starting member 7 is formed by polishing will be described with reference to FIGS. 15 to 17.

  In the fifth embodiment, the anode electrode 5 is formed of a thin silver plate. On the surface of the anode electrode 5, convex nucleation starting point portions 7 are formed at a plurality of locations. The plurality of nucleation starting point portions 7 are formed by polishing the surface of the anode electrode 5 with a file to form a plurality of grooves 31. As described above, the surface is polished with a coarse cloth file of # 80 to # 200 in order to form the nucleation starting point portion 7 having a height h of 5 μm or more and 100 μm or less. Of the nucleation starting point portion 7, the nucleation starting point portion 7 in which the angle θ sandwiched between the hypotenuses 20a and 20b is greater than 0 ° and not more than 90 ° is suitable for stable nucleation.

  According to the present embodiment, the nucleation starting point portion 7 can be formed easily and inexpensively with respect to the method of machining with a drill. Further, since the number of nucleation starting points can be increased, durability can be improved.

  The silver plate (anode electrode 5) polished with a coarse file of # 80 and # 200 includes protrusions having a height h of 5 μm or more and 100 μm or less, and it was confirmed that nucleation occurs stably. On the other hand, when the surface roughness and nucleation performance were evaluated by the method of polishing the silver plate (anode electrode 5) with a file, the silver plate polished with a fine # 1000 file became convex of 5 μm or less, and nucleation was stable. It was confirmed not to.

  As in the first and second embodiments described above, a process for forming the spiral nucleation starting point portion 7 on the peripheral surface of the anode electrode body 5a, and a fine protrusion using a nipper or the like as in the third embodiment. Machining to form a part-like nucleation origin 7, machining to form the nucleation origin 7 by a cutter as in the fourth embodiment, or polishing with a file as in the fifth embodiment Prior to processing to form the portion 7, particles of the heat storage material may be attached in advance.

  Although several embodiments of the present invention have been described above, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the gist of the invention. These embodiments and modifications thereof are included in the scope of the invention, and also included in the invention described in the claims and the equivalent scope thereof.

  DESCRIPTION OF SYMBOLS 1 ... Thermal storage apparatus, 3 ... Thermal storage tank, 4 ... Thermal storage material, 5 ... Anode electrode, 6 ... Cathode electrode, 7 ... Nucleation origin part, 7a, 7b ... Hypothesis of nucleation origin part, (theta) ... Nucleation origin part , H: height of the nucleation starting point, 12: voltage applying means

Claims (7)

A heat storage tank,
A heat storage material accommodated in the heat storage tank and capable of being supercooled;
An anode electrode having a nucleation starting point portion formed by a tapered protrusion, the nucleation starting point portion being disposed in contact with the heat storage material;
A cathode electrode disposed away from the anode electrode and in contact with the heat storage material;
Voltage applying means for applying a voltage between the electrodes;
A heat storage device comprising:   2. The heat storage device according to claim 1, wherein the nucleation starting point portion has a substantially triangular shape, and an angle between two oblique sides of the triangle is larger than 0 ° and not larger than 90 °.   The heat storage device according to claim 2, wherein a height of the nucleation starting point portion is 5 μm or more and 100 μm or less.   When the height of the nucleation starting portion is 5 μm or more and 100 μm or less, and the height is represented by h, and the volume of the nucleation starting portion is represented by S, the volume S is 0 <S The heat storage device according to claim 1, which is in a range of ≦ (πh3) / 3.   The heat storage device according to claim 1, wherein the nucleation starting point is spiral.   The heat storage device according to claim 1, wherein the cathode electrode has a cylindrical shape and is disposed so as to surround the anode electrode.   The heat storage device according to claim 1, wherein the nucleation starting portion is formed by any one of cutting, shearing, and polishing.

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