JP2006038266A - Heat storage device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To increase heat storage quantity by efficiently coagulating and melting a phase-change material while reducing an equipment cost. <P>SOLUTION: This heat storage device stores the heat by utilizing the latent heat obtained by coagulating and melting the phase-change material 1. In the heat storage device, the phase-change material 1 and heat transfer liquid 3 having a specific gravity larger than that of the phase-change material 1 are filled in a heat storage tank 2, and the phase-change material 1 is stacked on the heat transfer liquid 3. Further a heat conduction member 7 extended in the vertical direction is mounted in the heat storage tank 2, a lower part of the heat conduction member 7 is thermally connected with the heat transfer liquid 3, and its upper part is thermally connected with the phase-change material 1. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an apparatus for solidifying and melting a phase change material and storing heat using the latent heat. In this specification, “heat storage” is to be interpreted in a broad sense, and includes not only a state where heat energy is stored, but also a state where heat energy can be absorbed. For example, the state in which the phase change material is cooled and solidified and melted to absorb heat energy is also regarded as heat storage. That is, both a state in which heat energy is stored and a state in which heat energy can be absorbed are defined as “heat storage”.

  Water is a phase change material that is melted at 0 ° C. Paraffin-based phase change materials have been developed as phase change materials that solidify and melt at a temperature of 0 ° C. or higher. The device that solidifies and melts the phase change material and uses latent heat to store heat has the advantage of being compact and capable of increasing the amount of heat storage. The phase change material can be stored in, for example, midnight power and used for cooling or heating. Cooling solidifies the phase change material with midnight power. When the phase change material melts, the room is cooled by the heat of fusion taken from the surroundings. For cooling, a phase change material having a low melting temperature is used. Heating melts the phase change material with midnight power. The room is heated by the solidification heat generated when the phase change material solidifies. Use a phase change material with a high melting temperature for heating.

  A heat storage device using a paraffinic phase change material as a phase change material has been developed (see Patent Document 1). The heat of fusion of a phase change material such as a paraffinic phase change material is relatively large compared to sensible heat, and a device that solidifies and melts the heat to store heat can increase the amount of heat stored. However, the phase change material has a drawback that it is difficult to quickly solidify the whole. This is because the heat conduction in the solidified state is poor. For example, when a heat exchange pipe is inserted into the phase change material and a low-temperature liquid is allowed to flow through the heat exchange pipe to cool and solidify the phase change material, the area around the heat exchange pipe is solidified, but the solidified portion expands quickly. Not. This is because the heat conduction of the solidified phase change material is poor.

  Substantially heat conduction can be improved by filling the phase change material with glass beads or alumina beads so as to contact each other. This is because glass beads and alumina beads that are in contact with each other conduct heat. However, when these glass beads or alumina beads are filled in the phase change material, there is a drawback that the amount of the phase change material is reduced and the heat storage amount with respect to the volume is reduced. In addition, since the glass beads and alumina beads are filled even though the heat storage amount is reduced, there is a disadvantage that the cost of parts becomes extremely high.

In order to eliminate this drawback, the present inventor puts a plurality of metal pipes in a casing filled with a phase change material, contacts the metal pipes with each other, and solidifies and melts the phase change material by heat conduction of the metal pipe. An apparatus to be developed was developed (see Patent Document 2).
JP 2000-320988 A JP 2004-156793 A

  Since the cooling device having this structure uses a large number of metal pipes, the equipment cost increases. Moreover, since a metal pipe is put in the heat storage tank, there is a disadvantage that the amount of the paraffinic phase change material that can be filled is reduced and the amount of heat storage is reduced. In particular, in order to solidify the paraffinic phase change material more uniformly, it is necessary to use a large number of metal pipes, which increases the equipment cost, and reduces the amount of paraffinic phase change material to reduce heat storage. There are drawbacks. Furthermore, since the paraffinic phase change material is uniformly solidified through the metal pipe, there is a drawback that it is difficult to solidify efficiently compared to a structure in which the paraffinic phase change material is directly solidified.

  The present invention has been developed for the purpose of solving this drawback. An important object of the present invention is to provide a heat storage device capable of increasing the amount of heat storage by efficiently solidifying and melting the phase change material while reducing the equipment cost.

  The heat storage device of the present invention solidifies and melts the phase change material 1 and stores heat using the latent heat. The heat storage device fills the heat storage tank 2 with the phase change material 1 and the heat transfer liquid 3 having a larger specific gravity than the phase change material 1, and the phase change material 1 is stacked on the heat transfer liquid 3. Yes. Further, a heat conductor 7 extending in the vertical direction is disposed in the heat storage tank 2, and the lower part of the heat conductor 7 is thermally coupled to the heat transfer liquid 3 and the upper part is thermally coupled to the phase change material 1.

  The heat storage device of the present invention can efficiently store heat in the phase change material by using the heat transfer liquid 3 having a thermal conductivity larger than that of the phase change material 1. The phase change material 1 can be a paraffin phase change material. In the heat storage device of the present invention, the freezing point of the phase change material 1 can be higher than 0 ° C., and the heat transfer liquid 3 can be water. In the heat storage device of the present invention, the heat conductor 7 can be made of metal. Instead of metal, carbon fiber or ceramic can be used. The heat conductor 7 can be either a metal pipe or a metal plate. Furthermore, the heat storage device of the present invention can dispose the heat transfer tube 4 in the heat transfer liquid 3, cool the heat transfer liquid 3 with the heat transfer tube 4, or cool the heat transfer tube 4 with the heat transfer liquid 3. .

  The heat storage device of the present invention has an advantage that the amount of heat storage can be increased by efficiently solidifying and melting the phase change material while reducing the equipment cost. That is, the heat storage device of the present invention fills the heat storage tank in a state where the phase change material is laminated on the heat transfer liquid having a larger specific gravity than the phase change material, and stores the heat conductor extended in the vertical direction This is because it is disposed in the tank and the lower part of the heat conductor is thermally coupled to the heat transfer liquid and the upper part is thermally coupled to the phase change material.

  Embodiments of the present invention will be described below with reference to the drawings. However, the Example shown below illustrates the thermal storage apparatus for materializing the technical idea of this invention, Comprising: This invention does not specify a thermal storage apparatus as the following.

  Further, in this specification, in order to facilitate understanding of the scope of claims, numbers corresponding to the members shown in the examples are indicated in the “claims” and “means for solving problems” sections. It is added to the members. However, the members shown in the claims are not limited to the members in the embodiments.

  The heat storage device shown in FIGS. 1 and 2 solidifies and melts the phase change material 1 and stores heat using the latent heat. This apparatus can store heat energy by solidifying or melting the phase change material 1 with midnight power. In particular, the heat storage device of the present invention is suitable for cooling and cooling. This heat storage device solidifies the phase change material 1 with midnight power. Since the solidified phase change material 1 takes heat from the surroundings when it melts, that is, cools, it can be used for daytime cooling or cooling. The cooling can be used for a refrigerator or the like that solidifies the phase change material 1 with midnight power and cools it during the daytime. If the heat storage device is used to cool or cool in the daytime using the late-night power, the late-night power can be used effectively and the peak power in the daytime can be lowered. However, the heat storage device of the present invention can also be used for heating and heating.

  In the heat storage device shown in FIGS. 1 and 2, a heat storage tank 2 is filled with a phase change material 1 and a heat transfer liquid 3 having a larger specific gravity than the phase change material 1. Since the phase change material 1 is lighter than the heat transfer liquid 3, the phase change material 1 is laminated on the heat transfer liquid 3, in other words, the phase change material 1 floats on the heat transfer liquid 3. .

  The heat storage tank 2 has a watertight structure in which the heat transfer liquid 3 and the phase change material 1 do not leak. The phase change material 1 decreases in volume when solidified from the molten state, and conversely melts from the solidified state and increases in volume. Therefore, the heat storage tank 2 has a structure capable of absorbing the volume change of solidification and melting of the phase change material 1. In this structure, for example, a heat storage tank is used as a sealed structure, a discharge pipe is connected to the upper part, and the discharge pipe is extended upward. The discharge pipe is connected to the phase change material. In addition, the heat storage tank can be filled with air and the exhaust pipe can be connected to the air layer. Furthermore, the heat storage tank in which the air is placed has a hermetic structure and can change the volume of the air, in other words, change the internal pressure and absorb the volume change of the phase change material. Moreover, the heat storage tank in which air is put can open a part so that it may connect with an upper air layer, and can absorb the volume change of a phase change material.

  The heat storage tank 2 is thermally insulated to prevent wasteful heat dissipation and heat absorption. For heat insulation, a heat insulating material (not shown) is stretched outside or inside the heat storage tank 2 to reduce heat transfer. The heat storage tank 2 can have a shape that can be filled with a predetermined amount of the heat transfer liquid 3 and the phase change material 1. The heat storage tank 2 is made of metal, concrete, or plastic.

  The phase change material 1 stores energy by latent heat and sensible heat that solidify and melt. The phase change material 1 is selected so that the temperature at which it solidifies and melts, that is, the melting temperature is the optimum temperature for the application. For example, a phase change material having a melting temperature of 1 to 12 ° C. is used for a cooling heat storage device. As a phase change material having this melting temperature, there is a paraffin type material. A phase change material having a melting temperature of 20 to 120 ° C. is used for a heat storage device for heating. The paraffinic phase change material can adjust the melting temperature by the number of carbons bonded. As the number of carbons increases and the molecular weight increases, the melting temperature increases. The phase change material is thermally melted at a temperature higher than the melting temperature. Furthermore, it is solidified at a temperature lower than the melting temperature. The phase change material is melted from the solidified state and absorbs heat from the surroundings. That is, the surroundings are cooled in this state. When it solidifies from a molten state, it releases heat. The surroundings are heated in this state. The phase change material 1 repeats solidification and melting, and absorbs or releases thermal energy corresponding to latent heat.

  A heat transfer liquid 3 having a thermal conductivity larger than that of the phase change material (1) is suitable. This is because the heat transfer liquid can efficiently conduct heat between the heat transfer tube 4 and the phase change material 1. The heat transfer liquid 3 is either water or a brine liquid in which an inorganic material that lowers the melting point such as sodium chloride is dissolved in water. When a paraffin phase change material is used as the phase change material, the thermal conductivity of the paraffin phase change material is about 0.18 W / mk in a liquid state and 0.17 W / mk in a solid state. On the other hand, since the thermal conductivity of water is 0.59 W / mk in the liquid state, which is larger than that of the phase change material, water efficiently heats from the heat transfer tube to the phase change material and from the phase change material to the heat transfer tube. To communicate. The heat transfer liquid 3 is a liquid that does not solidify at a temperature at which the phase change material 1 is solidified. The heat transfer liquid 3 always contacts the phase change material 1 in a liquid state and exchanges heat with the phase change material 1. The heat storage device shown in FIG. 1 cools or heats the heat transfer liquid 3 via a heat transfer pipe 4 piped in a state of being immersed in the heat transfer liquid 3. Therefore, the heat transfer liquid 3 that is in the liquid state even when cooled or heated by the heat transfer tube 4 is used.

  An apparatus in which the freezing point of the phase change material 1 is higher than 0 ° C. can use water as the heat transfer liquid 3. When the freezing point of the phase change material 1 is lower than 0 ° C., a brine solution that does not solidify at 0 ° C. is used as the heat transfer liquid 3. However, even in an apparatus using a phase change material 1 having a freezing point of 0 ° C. or higher, a brine solution can be used as the heat transfer liquid 3. An apparatus that uses water for the heat transfer liquid 3 can make the heat transfer liquid 3 inexpensive. In particular, water is suitable as the heat transfer liquid 3 in a heat storage device that uses the phase change material 1 having a freezing point of 5 ° C. or higher. This is because the running cost can be reduced by using water that is inexpensive and easy to handle. When the freezing point of the phase change material 1 approaches 0 ° C., the temperature of the heat transfer liquid 3 for cooling and solidifying it needs to be close to 0 ° C. or 0 ° C. or less. Therefore, when the temperature of the phase change material 1 becomes 5 ° C. or lower, a brine solution having a freezing point lower than 0 ° C. is preferably used as the heat transfer liquid 3. That is, the solidification point of the heat transfer liquid 3 is set to be 3 ° C. or more, preferably 5 ° C. or more lower than the solidification point of the phase change material 1 so that the heat transfer liquid 3 does not solidify in the state where the phase change material 1 is solidified. Good.

  As shown in FIG. 1, the heat storage device that cools or heats the heat transfer liquid 3 with the heat transfer tube 4 is in a state where the heat transfer tube 4 can be completely immersed in the heat transfer liquid 3, in other words, the entire circumference of the heat transfer tube 4. The heat transfer tank 3 is filled with an amount of heat transfer liquid 3 that can be piped into the heat transfer liquid 3. The heat storage device of FIG. 1 has one heat transfer tube 4 piped to the heat transfer liquid 3, but a plurality of heat transfer pipes are piped to the heat transfer liquid, or a heat transfer pipe having fins fixed to the surface is piped. can do. This heat storage device fills the heat storage tank with an amount of heat transfer liquid that can immerse all the heat transfer tubes in the heat transfer liquid. The heat storage device in which the heat transfer tube 4 is completely piped in the liquid of the heat transfer liquid 3 or the fins and the heat transfer pipe are arranged in the liquid cools the heat transfer liquid 3 efficiently with the heat transfer tube 4. Or it can be heated.

  In the heat storage device shown in FIG. 1, a heat transfer pipe 4 is piped to the heat transfer liquid 3, and the circulating liquid is circulated through the heat transfer pipe 4. This apparatus circulates the circulating liquid that is passed through the heat transfer tube 4 through the chiller 5 and the external heat exchanger 6 that are a cooler or a heater. The chiller 5 and the external heat exchanger 6 are connected in series to circulate the circulating fluid that is passed through the heat transfer tube 4. The chiller 5 cools the circulating liquid to solidify the phase change material 1 or heats the circulating liquid to melt the solidified phase change material 1. The apparatus shown in this figure circulates the circulating fluid through the heat transfer tube 4 to cool or heat the heat transfer fluid 3, so that it is not necessary to circulate the heat transfer fluid 3 to the chiller 5 or the external heat exchanger 6. For this reason, the heat transfer liquid 3 can always be at a constant level. Further, since the heat transfer liquid 3 and the circulating liquid are not mixed, different liquids such as water and brine can be used for the heat transfer liquid 3 and the circulating liquid.

  The heat storage device shown in FIG. 2 circulates the heat transfer liquid 3 through the chiller 5 and the external heat exchanger 6 as a circulating liquid. The heat transfer liquid 3 is circulated through the chiller 5 and the external heat exchanger 6. The chiller 5 directly cools the heat transfer liquid 3 to solidify the phase change material 1 or heats it to melt the solidified phase change material 1. In the apparatus of this figure, the heat transfer liquid 3 is directly cooled or heated by the chiller 5, so that the heat transfer liquid 3 can be efficiently cooled or heated by the chiller 5. This apparatus is suitable for an apparatus that uses water for the heat transfer liquid 3. This is because water can be circulated to the heat storage tank 2, the chiller 5, and the external heat exchanger 6.

  The above apparatus operates the chiller 5 with midnight power to solidify or melt the phase change material 1 to store heat. The external heat exchanger 6 is a heat exchanger for air conditioning or a heat exchanger such as a refrigerator or a cooler. The heat exchanger for air conditioning cools or heats the room by passing room air. Moreover, the heat exchanger of a refrigerator or a cooler cools the refrigerator or the cooler.

  Further, in the heat storage device, a heat conductor 7 extended in the vertical direction is disposed in the heat storage tank 2. The heat conductor 7 has a lower portion thermally coupled to the heat transfer liquid 3 and an upper portion thermally coupled to the phase change material 1. The heat conductor 7 is a metal such as copper or aluminum. Since the metal has excellent heat conduction characteristics, the heat of the heat transfer liquid 3 is efficiently conducted to the phase change material 1, and the heat of the phase change material 1 is conducted to the heat transfer liquid 3. The heat conductor 7 is optimally a metal pipe. The metal pipe is a round pipe or a square pipe. The pipe can be provided with through holes and filled with the phase change material 1 or the heat transfer liquid 3 therein. However, a metal rod or a metal plate can also be used for the heat conductor. Since the heat conductor 7 conducts heat to the phase change material 1 and the heat transfer liquid 3, the lower end is immersed in the heat transfer liquid 3 to be in a heat-bonded state, and the upper part is inserted into the phase change material 1 to be heat-bonded. State.

  The heat conductor 7 changes the area that is thermally coupled to the phase change material 1 and the heat transfer liquid 3, in other words, the area that contacts the phase change material 1 and the heat transfer liquid 3, so that the phase change material 1 and the heat transfer liquid 3 are changed. The amount of heat conducted to the heat conductor 7 can be controlled. When the area where the heat conductor 7 is thermally coupled to the phase change material 1 or the heat transfer liquid 3 is reduced, the amount of heat conducted from the phase change material 1 or the heat transfer liquid 3 to the heat conductor 7 is reduced. Conversely, when the area where the heat conductor 7 is thermally coupled to the phase change material 1 or the heat transfer liquid 3, that is, the contact area increases, the amount of heat conducted from the phase change material 1 or the heat transfer liquid 3 to the heat conductor 7 increases. Become. Utilizing this characteristic, the amount of heat energy extracted from the phase change material 1 can be controlled. For example, when the heat storage device is used for a cooling device that solidifies the phase change material 1 with midnight power, the area where the heat conductor 7 is thermally coupled to the phase change material 1 or the heat transfer liquid 3 is changed to change the phase change material 1. In other words, the amount of heat for cooling the heat transfer liquid 3 by melting the solidified phase change material 1 can be controlled. When the outside air temperature is high and the amount of cooling heat is increased, the area where the heat conductor 7 is thermally coupled to the phase change material 1 and the heat transfer liquid 3 is increased, and the amount of heat that the phase change material 1 cools the heat transfer liquid 3. Can do more. When the cooling load is small and the cooling heat quantity is small, the area where the heat conductor 7 is thermally coupled to the phase change material 1 and the heat transfer liquid 3 is reduced, and the phase change material 1 cools the heat transfer liquid 3. The amount of heat can be reduced. The following mechanism can be adopted as a mechanism for changing the area where the heat conductor 7 is thermally coupled to the phase change material 1 and the heat transfer liquid 3.

[Mechanism for reducing the amount of heat conduction between the phase change material and the heat transfer liquid by reducing the area where the heat conductor is thermally coupled to the phase change material or the heat transfer liquid]
(1) The heat conductor 7 is moved in the direction of the phase change material 1 so that the area where the heat conductor 7 is thermally coupled to the heat transfer liquid 3 is smaller than the area where the heat conductor 7 is thermally coupled to the phase change material 1. This mechanism increases the area where the heat conductor 7 is thermally coupled to the phase change material 1, but reduces the area where the heat conductor 7 is thermally coupled to the heat transfer liquid 3, so the amount of heat conducted between the heat transfer liquid 3 and the heat conductor 7. To reduce the amount of heat conducted by the heat conductor 7 between the phase change material 1 and the heat transfer liquid 3.
(2) The heat conductor 7 is moved in the direction of the heat transfer liquid 3 so that the area where the heat conductor 7 is thermally coupled to the phase change material 1 is made smaller than the area thermally coupled to the heat transfer liquid 3. This mechanism increases the area where the thermal conductor 7 is thermally coupled to the heat transfer liquid 3, but reduces the area where the thermal conductor 7 is thermally coupled to the phase change material 1, and thus the amount of heat conducted between the phase change material 1 and the thermal conductor 7. To reduce the amount of heat conducted by the heat conductor 7 between the phase change material 1 and the heat transfer liquid 3.
(3) The heat conductor 7 is inclined with respect to the interface between the phase change material 1 and the heat transfer liquid 3. In this mechanism, the area where the heat conductor 7 is thermally coupled to both the phase change material 1 and the heat transfer liquid 3 does not change, but the heat conductor 7 is thermally coupled to both the phase change material 1 and the heat transfer liquid 3. The region is limited to the vicinity of the boundary portion between the phase change material 1 and the heat transfer liquid 3. For this reason, the efficiency of the overall heat exchange between the phase change material 1 and the heat transfer liquid 3 is reduced, and the amount of conduction heat is reduced.

  FIG. 3 shows a state in which the heat conductor 7 efficiently conducts the heat of the heat transfer liquid 3 to the phase change material 1 and efficiently conducts the heat of the phase change material 1 to the heat transfer liquid 3. The arrows in the figure indicate the direction in which the heat transfer liquid 3 cools the phase change material 1. Thus, cooling takes heat away and heat energy is conducted in the opposite direction of the arrow. The heat conductor 7 is thermally coupled to both the heat transfer liquid 3 and the phase change material 1 to efficiently conduct heat conduction between the heat transfer liquid 3 and the phase change material 1. When the paraffin phase change material 1 is solidified, the specific gravity increases and settles to the bottom. The paraffinic phase change material 1 that has solidified and settled to the bottom has a very poor thermal conductivity. For this reason, when the solidified phase change material 1 </ b> A settles on the boundary surface with the heat transfer liquid 3, this deteriorates the heat conduction between the heat transfer liquid 3 and the phase change material 1. For this reason, the liquid phase change material 1B on the solidified phase change material 1A is not cooled by the heat transfer liquid 3 and does not solidify. Since the heat conductor 7 is thermally coupled to the heat transfer liquid 3 at the lower part and the phase change material 1 at the upper part, the heat conductor 7 penetrates through the layer of the solidified phase change material 1A, and the liquid phase change with the heat transfer liquid 3 The heat conduction with the material 1B is made efficient. For this reason, even if the phase change material 1 solidifies and settles to the bottom, the heat transfer liquid 3 efficiently cools and solidifies the phase change material 1 through the heat conductor 7. Further, the liquid phase change material 1B which does not solidify is cooled by the heat conductor 7 and convects. Therefore, the heat conductor 7 cools the phase change material 1 uniformly. In the state where the heat transfer liquid 3 cools and solidifies the phase change material 1, the heat energy is conducted from the phase change material 1 to the heat transfer liquid 3 via the heat conductor 7. The above states occur in a state in which the phase change material 1 is solidified to store the cooling energy, and a state in which the external heat exchanger 6 is heated with the heat energy that has been solidified from the melted phase change material 1 and stored. . That is, the heat transfer liquid 3 is cooled by the chiller 5, the cooled heat transfer liquid 3 cools the phase change material 1, and heat is stored in the phase change material 1 that solidifies the cooling energy, and the melted phase change. The material 1 is solidified, and the phase change material 1 is heated to heat the heat transfer liquid 3 through the heat conductor 7 and the external heat exchanger 6 is heated with the stored heat energy.

  On the contrary, in the state where heat energy is conducted from the heat transfer liquid 3 to the phase change material 1, the solidified phase change material 1 is melted. This state occurs in a state in which the solidified phase change material 1 is melted and stored, and a state in which the external heat exchanger 6 is cooled by the cooling energy stored by melting the solidified phase change material 1. That is, the heat transfer liquid 3 is heated by the chiller 5, the heated heat transfer liquid 3 heats the phase change material 1, and heat is accumulated in the phase change material 1 that melts thermal energy, and solidifies. The phase change material 1 is melted, and the phase change material 1 cools the heat transfer liquid 3 through the heat conductor 7 to cool the external heat exchanger 6 with the stored cooling energy.

  The graph of FIG. 4 shows that the heat conductor 7 achieves an extremely excellent effect. This figure has shown the ratio of the thermal storage amount of the apparatus which provided the heat conductor with respect to the apparatus without a heat conductor. This figure shows the amount of heat storage (latent heat) stored and solidified by the phase change material by a chain line A, and the amount of heat storage (sensible heat) stored and stored by the phase change material by a one-dot chain line B. The total heat storage amount to be stored is indicated by a solid line C. As shown by the solid line C, the thermal energy stored in the apparatus of the present invention provided with the heat conductor 7 increases as time passes. For example, after 2 hours, the heat energy stored is more than twice that of a device without a heat conductor, and about 2.2 times at the peak.

However, the graph of FIG. 4 is measured under the following conditions.
(1) The internal volume of the heat storage tank 2 is 76 mm × 65 mm × 206 mm in length × width × height.
(2) The heat transfer tube 4 is a single copper pipe having an outer diameter of 6 mm and an inner diameter of 4 mm.
(3) The heat conductor 7 is a single copper pipe extending from the bottom of the heat storage tank 2 to the ceiling.
(4) The copper pipe of the heat conductor 7 has an outer diameter of 6 mm and an inner diameter of 4 mm.
(5) As the phase change material 1, a paraffin phase change material having a freezing point of 12 ° C. is used.
(6) Water is used as the heat transfer liquid 3 and the filling amount is 16 mm from the bottom.
(7) The phase change material 1 is filled on the heat transfer liquid 3 to fill the heat storage tank 2.
(8) The temperature of the circulating fluid passed through the heat transfer tube 4 is set to 2 ° C.
(9) The temperature of the first heat transfer liquid 3 and the phase change material 1 for starting the experiment is 27 ° C.

  The heat storage device of FIG. 1 is used for cooling in summer as follows. In this figure, the chiller 5 sucks and cools the circulating fluid discharged from the heat transfer tube 4 of the heat storage tank 2, and circulates the cooled circulating fluid through the heat transfer tube 4. The heat transfer tube 4 cools and solidifies the phase change material 1 via the heat transfer liquid 3 and the heat conductor 7. In this figure, the chiller 5 is operated at midnight power, for example, sucks a circulating fluid at 12 ° C., cools it to 7 ° C., and circulates it through the heat transfer tube 4. At midnight when the chiller 5 cools the circulating fluid, the switching valve 8 connected to both ends of the external heat exchanger 6 is connected so that the circulating fluid is circulated to the heat storage tank 2 without passing through the external heat exchanger 6. Can be switched. The 7 ° C. circulating liquid circulated through the heat transfer tube 4 of the heat storage tank 2 cools the heat transfer liquid 3, and the heat transfer liquid 3 solidifies the phase change material 1. Inside the heat storage tank 2, the heat transfer liquid 3 directly contacts the phase change material 1 and solidifies the phase change material 1 via the heat conductor 7. The temperature of the heat transfer liquid 3 that solidifies the phase change material 1 rises, and the circulating fluid that is heated thereby rises in temperature and is circulated to the chiller 5. In this operation, the phase change material 1 of the heat storage tank 2 is solidified, and the solidified phase change material 1 stores thermal energy as a state that takes away latent heat when converted into a liquid phase. When cooling, the circulating fluid in the heat transfer tube 4 is circulated to the external heat exchanger 6. The circulating fluid passing through the external heat exchanger 6 cools the room air and is heated from 7 ° C to 15 ° C. The heated circulating liquid is circulated through the heat transfer pipe 4 and cooled to the heat transfer liquid 3 inside the heat storage tank 2. The heat transfer liquid 3 is cooled by the latent heat of the phase change material 1. When circulating the circulating fluid in the heat transfer tube 4 through the external heat exchanger 6, the chiller 5 can be operated to cool the circulating fluid with both the latent heat of the phase change material 1 and the chiller 5.

  During heating, it operates as follows. In this state, the chiller 5 heats the circulating fluid circulated through the heat transfer tube 4. Heat transfer tube 4 heats phase change material 1 via heat transfer liquid 3 and stores thermal energy as a state in which phase change material 1 is melted. In this state, the chiller 5 is operated with midnight power to heat the circulating fluid and circulate it through the heat transfer tube 4. The circulating fluid 4 can be heated by using a heater instead of the chiller 5. Further, the heater can be built in the heat transfer liquid 3 to heat the heat transfer liquid 3 directly. The circulating fluid to be heated is circulated to the heat transfer tube 4 in the heat storage tank 2 without passing through the external heat exchanger 6. The circulating fluid circulated through the heat transfer tube 4 heats the heat transfer liquid 3, the heat transfer liquid 3 directly heats the phase change material 1, and heats the phase change material 1 via the heat conductor 7. Allow to melt by heating. The heat transfer liquid 3 that melts the phase change material 1 is cooled, and the cooled heat transfer liquid 3 is heated by the heat transfer tube 4. In this operation, the phase change material 1 in the heat storage tank 2 is melted, and the melted phase change material 1 stores thermal energy as a state that takes away latent heat when converted into a solid phase. When heating, the circulating fluid of the heat transfer tube 4 is circulated to the external heat exchanger 6. The circulating fluid passing through the external heat exchanger 6 is cooled by heating indoor air. The cooled circulating liquid is circulated through the heat transfer tube 4, and the heat transfer tube 4 is heated by the phase change material 1 through the heat conductor 7 and the heat transfer liquid 3. When circulating the circulating fluid through the external heat exchanger 6, the chiller 5 can be operated, or the heater can be energized to heat the circulating fluid both with the latent heat of the phase change material 1.

It is a schematic block diagram of the thermal storage apparatus concerning one Example of this invention, Comprising: It is a figure which shows the state which cools in summer. It is a schematic block diagram of the heat storage apparatus concerning the other Example of this invention. It is the schematic which shows the state in which the heat conductor of a thermal storage tank conducts the heat | fever of a heat transfer liquid to a phase change material. It is a graph which shows the ratio of the heat storage amount with respect to the conventional heat storage apparatus of the heat storage apparatus of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Phase change material 1A ... Solidified phase change material 1B ... Liquid phase change material 2 ... Heat storage tank 3 ... Heat transfer liquid 4 ... Heat transfer pipe 5 ... Chiller 6 ... External heat exchanger 7 ... Heat conductor 8 ... Switching valve

Claims (7)

A heat storage device that solidifies and melts the phase change material (1) and stores heat using the latent heat,
The heat storage tank (2) is filled with the phase change material (1) and the heat transfer liquid (3) having a higher specific gravity than the phase change material (1), and the phase change material is placed on the heat transfer liquid (3). In addition, the heat storage tank (2) is provided with a heat conductor (7) extending in the vertical direction, and the lower part of the heat conductor (7) is placed in the heat transfer liquid ( 3), a heat storage device formed by thermally coupling the upper part to the phase change material (1).   The heat storage device according to claim 1, wherein the thermal conductivity of the heat transfer liquid (3) is larger than the thermal conductivity of the phase change material (1).   The heat storage device according to claim 1, wherein the phase change material (1) is a paraffin phase change material.   The heat storage device according to claim 1, wherein the freezing point of the phase change material (1) is higher than 0 ° C, and the heat transfer liquid (3) is water.   The heat storage device according to claim 1, wherein the heat conductor (7) is one of metal, carbon fiber, and ceramic.   The heat storage device according to claim 5, wherein the heat conductor (7) is one of a metal pipe and a metal plate. The heat transfer pipe (4) is arranged in the heat transfer liquid (3), the heat transfer liquid (3) is cooled by the heat transfer pipe (4), or the heat transfer liquid (3) cools the heat transfer pipe (4). The heat storage device according to claim 1.

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