JP2014043203A - Heat storage device, air conditioning device and heat storage method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat storage device capable of easily determining whether or not a latent heat storage material can be supercooled, an air conditioning device and a heat storage method.SOLUTION: A heat storage device includes: a closed first circuit for circulating a medium in one direction; a heat exchanger installed in part of the first circuit and exchanging heat emitted by a heating element with the medium; a heat storage tank that is installed downstream of the first circuit and includes a latent heat storage material exchanging heat with the medium obtaining the heat emitted by the heating element; a first measurement part for measuring a temperature of the medium passing between the heat exchanger and the heat storage tank; a cooling part for cooling the medium when the temperature of the medium measured by the first measurement part is higher than a predetermined target temperature to make the temperature of the medium passing between the heat exchanger and the heat storage tank approximately equal to the target temperature; a measurement part for measuring an elapsed time since the latent heat storage material has exchanged heat with the medium and started a phase change from a solid phase to a liquid phase; and a determination part for determining whether or not the latent heat storage material can be supercooled, on the basis of the elapsed time.

Description

  Embodiments described herein relate generally to a heat storage device, an air conditioner, and a heat storage method using a latent heat storage material.

  In order to warm up an internal combustion engine and a transmission (a heating element), a technique for storing waste heat from the heating element in a latent heat storage material via a medium is known. When heat is applied to the latent heat storage material, the latent heat storage material stores heat by changing from a solid phase to a liquid phase. Even when the temperature of the liquid phase latent heat storage material is lowered, the liquid phase latent heat storage material is in a supercooled state in which the liquid phase is maintained. The latent heat storage material in a supercooled state is nucleated by applying a mechanical stimulus or voltage, and changes from a liquid phase to a solid phase. At this time, the heat stored in the process of phase change from the solid phase to the liquid phase is released. If a part of the solid phase remains when the phase of the latent heat storage material changes from the solid phase to the liquid phase, if the temperature of the latent heat storage material decreases, the whole will return to the solid phase, and supercooling Cannot be in a state. Therefore, when using a latent heat storage material for warm-up, the latent heat storage material needs to be in a supercooled state. Therefore, at the stage of heat storage, it is determined whether the phase change of the entire latent heat storage material from the solid phase to the liquid phase has been completed, that is, whether the latent heat storage material can be overcooled when the temperature of the latent heat storage material decreases. It is necessary to keep it.

  On the other hand, a technique for determining whether the latent heat storage material can be supercooled based on the temperature of the medium is known. However, since the temperature of the medium changes sequentially depending on the operating state of the heating element, it is difficult to easily determine whether the latent heat storage material can be supercooled based on the temperature of such a medium.

JP 2009-236433 A

  Provided are a heat storage device, an air conditioner, and a heat storage method capable of easily determining whether or not a latent heat storage material can be supercooled.

  The heat storage device according to the embodiment is a heat storage device that stores heat released from a heating element via a medium, and is provided in a closed first circuit for circulating the medium in one direction and a part of the first circuit. A heat exchanger for exchanging heat released from the heating element with the medium, and provided downstream of the heat exchanger of the first circuit in the direction in which the medium circulates. A heat storage tank including a latent heat storage material that exchanges heat with the medium that has obtained heat released from the medium, and a first measurement unit that measures the temperature of the medium that passes between the heat exchanger and the heat storage tank And when the temperature of the medium measured by the first measuring unit is higher than a predetermined target temperature, the medium is cooled, and the temperature of the medium passing between the heat exchanger and the heat storage tank is determined. A cooling unit that is substantially equal to a target temperature, and the latent heat storage material is between the medium and A measuring unit that measures an elapsed time after starting the phase change from the solid phase to the liquid phase, and a determination unit that determines whether the latent heat storage material can be supercooled based on the elapsed time. Prepare.

  The air conditioner of an embodiment is an air conditioner provided with the above-mentioned heat storage device, is connected to the first circuit at a second branch point with a nucleation device that nucleates the latent heat storage material, and bypasses the heat storage tank A second control valve capable of switching the flow path of the medium to either the first circuit or the second bypass circuit at the second branch point, and the determination unit including the latent heat storage A second control unit that controls switching of the second control valve and switches the flow path of the medium to the second bypass circuit when it is determined that the material can be supercooled.

  The heat storage method according to the embodiment includes a medium, a closed first circuit for circulating the medium in one direction, and heat provided by a part of the first circuit between the medium and the heat released from the heating element. Heat exchange is performed between a heat exchanger that exchanges heat with the medium and a medium that is provided downstream of the heat exchanger of the first circuit in the direction in which the medium circulates and that obtains heat released by the heating element. A heat storage method in a heat storage device or an air conditioner comprising a heat storage tank containing a latent heat storage material, the first step of circulating the medium, and the temperature of the medium passing between the heat exchanger and the heat storage tank A second step of measuring the medium, and cooling the medium when the temperature of the medium measured in the second step is higher than a predetermined target temperature, and passing between the heat exchanger and the heat storage tank A third step in which the temperature of the medium is approximately equal to the target temperature. And a fourth step of measuring an elapsed time after the latent heat storage material exchanges heat with the medium and starts a phase change from a solid phase to a liquid phase, and a determination unit includes the elapsed time And a fifth step of determining whether or not the latent heat storage material can be supercooled.

The block diagram which shows the thermal storage apparatus which concerns on 1st embodiment. The block diagram which shows the control apparatus which concerns on 1st embodiment. The flowchart which shows operation | movement of the thermal storage apparatus which concerns on 1st embodiment. The block diagram which shows the control apparatus which concerns on a 1st modification. An example of the simulation result which concerns on a 1st modification. The block diagram which shows the thermal storage apparatus which concerns on a 2nd modification. The block diagram which shows the control apparatus which concerns on a 2nd modification. The block diagram which shows the thermal storage apparatus which concerns on 2nd embodiment. An example of the simulation result which concerns on 2nd embodiment. The block diagram which shows the air conditioner which concerns on 3rd embodiment. The block diagram which shows the control apparatus which concerns on 3rd embodiment.

  Hereinafter, embodiments for carrying out the invention will be described.

(First embodiment)
FIG. 1 is a block diagram showing a heat storage device according to the first embodiment. In the present embodiment, the heat storage device is, for example, in an electric vehicle (EV) (hereinafter referred to as a vehicle) having a storage battery, a motor, an inverter, and an electronic control unit (ECU) that controls them. It can be used for an in-vehicle air conditioner. For example, a heat storage device is provided in the vicinity of a motor or an inverter of an electric vehicle having an air conditioner. By preliminarily storing heat (waste heat) released from motors, inverters, etc. in the heat storage device, when the air conditioner needs to be warmed up, the heat stored in the heat storage device can be used. it can.

  The heat storage device 1000 in FIG. 1 includes a first circuit 101. In the first circuit 101, a medium for heat exchange circulates. The medium is a liquid or gas capable of transporting heat obtained by heat exchange. In the present embodiment, for example, water is used. Further, the heat released from the heating element 10 that can operate (heat generation) and non-operation (non-heating) is heat exchanged with the medium, and heat exchange is performed with the heat exchanger 15 and the heating element 10 that give heat to the medium. A heat storage tank 20 including a latent heat storage material 25 that exchanges heat with a later medium and receives heat from the medium is provided. Here, the heating element 10 is a device that generates heat in the vehicle, such as a storage battery, a motor, or an inverter. In addition, a cooling unit 30 that adjusts the temperature of the medium to be substantially the target temperature, and a first measuring unit 130 that measures the temperature of the medium before passing through the heat storage tank 20 are provided.

  The first circuit 101 is a pipe that annularly connects the heat exchanger 15, the heat storage tank 20, and the cooling unit 30, and the medium circulates in the pipe. That is, in FIG. 1, the heat exchanger 15 and the heat storage tank 20, the heat storage tank 20 and the cooling unit 30, and the cooling unit 30 and the heat exchanger 15 are connected. Note that the first circuit 101 is a metal material (for example, copper) having excellent thermal conductivity in a portion where heat exchange is performed in order to enable heat exchange between the medium and the heating element 10 and between the medium and the latent heat storage material 25. It is preferable that Moreover, about the other part, in order to suppress the thermal radiation from the pipe surface, the resin member etc. which are excellent in heat resistance and excellent in heat insulation can be used.

  The medium circulates through the first circuit 101 while repeating heat exchange with the heating element 10 and the heat storage tank 20 by sequentially passing through the heat exchanger 15, the heat storage tank 20, and the cooling unit 30. That is, the medium that has passed through the cooling unit 30 passes through the heat exchanger 15 by circulating through the first circuit 101. The medium is driven by a pump or the like (not shown).

  The latent heat storage material 25 is a material that can change between a solid phase and a liquid phase by heat exchange and can take a supercooled state in the liquid phase. In addition, it is a material that nucleates and changes phase to a solid phase when given an input such as impact or voltage application in a supercooled state. In this embodiment, for example, sodium acetate hydrate is used.

  The heating element 10 is provided in the vicinity of the heat exchanger 15, for example, in contact with the heat exchanger 15. The heating element 10 gives heat released outside by operating when the vehicle is driven to the medium circulating through the first circuit 101 via the heat exchanger 15.

  The heat storage tank 20 is a container that is provided downstream of the heat exchanger 15 of the first circuit 101 and accommodates the latent heat storage material 25. Here, the downstream is defined with reference to the direction in which the medium in the first circuit 101 flows. The heat storage tank 20 connects a pipe (not shown) penetrating the inside of the container to the first circuit 101. In the heat storage tank 20, when the medium after heat exchange with the heating element 10 passes through the pipe, the latent heat storage material 25 receives the heat of the medium through heat exchange. Here, a pipe that penetrates the inside of the container is a part of the first circuit 101. That is, the first circuit 101 passes through the heat storage tank 20.

  The cooling unit 30 includes a radiator 31 and a fan 32 that faces the radiator 31. The radiator 31 is connected to the first circuit 101. The radiator 31 receives heat from the medium passing through the radiator 31, and cools the medium by releasing the heat to the outside. The fan 32 rotates to generate an air flow toward the radiator 31 and cool the radiator 31. A first control unit 41 (described later) controls the rotational speed of the fan 32, so that the fan 32 generates and adjusts the air volume of the air flow that strikes the radiator 31. Therefore, the surface temperature of the radiator 31 is cooled by adjusting the air volume of the air flow hitting the radiator 31, and the temperature of the medium passing through the radiator 31 is cooled.

  The cooling unit 30 includes a first bypass circuit 102 and a first control valve 103. The first bypass circuit 102 is connected to the first circuit 101 via the first control valve 103 at the branch point A and is connected to the first circuit 101 at the branch point B, thereby bypassing the radiator 31. The first control valve 103 switches the flow path of the medium that has passed through the first circuit 101 and reached the first control valve 103 to one of the first circuit 101 and the first bypass circuit 102. Here, the state of switching (or maintaining) the flow path of the medium to the first circuit 101 is “first control valve: OFF”, and the state of switching (or maintaining) the flow path of the medium to the first bypass circuit 102 is “ The first control valve is defined as “ON”.

  The first measuring unit 130 is a temperature sensor provided between the heat exchanger 15 and the heat storage tank 20. The 1st measurement part 130 measures the temperature (henceforth 1st temperature) of the medium which passes between between the heat exchanger 15 and the thermal storage tank 20. FIG. That is, the first temperature of the medium after receiving heat by heat exchange with the heating element 10 and before giving heat to the latent heat storage material 25 by heat exchange with the latent heat storage material 25 is measured.

  1 includes a control device 200 and a storage device 300. As the control device 200, an arithmetic processing device such as a CPU or MPU is used. Further, as the storage device 300, a recording medium such as a memory or an HDD is used.

  FIG. 2 is a block diagram showing the control device 200 of FIG.

  2 includes a command unit 40 that controls the operation of the heating element 10, a first control unit 41 that controls the cooling unit 30 to cool the medium when the first temperature is higher than the target temperature, and latent heat storage. The measurement part 42 which measures the elapsed time after the material 25 started the phase change from a solid phase to a liquid phase, and the latent heat storage material 25 complete | finishes the phase change to a liquid phase based on the elapsed time which the measurement part 42 measures It has the determination part 43 which determines whether it carried out as a logic module.

  The command unit 40 controls the operation of the heating element 10 based on an instruction from a driver who drives the vehicle. That is, ON / OFF of the operation of the heating element 10 is controlled. The heat storage device 1000 stores the heat generated by the heating element 10 from when the command unit 40 controls the operation of the heating element 10 to ON until it is controlled to OFF.

  The first control unit 41 compares the first temperature of the medium measured by the first measurement unit 130 with the target temperature, controls the rotational speed of the fan 32, and indirectly determines the air volume of the airflow hitting the radiator 31. Control. Further, the first control unit 41 controls switching of the first control valve 103 between ON and OFF. Here, the target temperature can be stored in the storage device 300 by predetermined. The target temperature is a constant value that can be determined in a range that is equal to or higher than the melting point of the latent heat storage material 25 and that is equal to or lower than the heat resistant temperature of a device (for example, a semiconductor element of an inverter) that constitutes the vehicle.

  For example, the first control unit 41 switches the first control valve 103 to ON when the first temperature of the medium is lower than the target temperature. At this time, the medium bypasses the radiator 31 by passing through the first bypass circuit 102. The medium passing through the first circuit 101 rises in temperature by obtaining heat from the heating element 10 without being cooled. On the other hand, when the first temperature of the medium falls within a predetermined range with reference to the target temperature, the rotational speed of the fan 32 is controlled by P control, PI control, according to the difference between the first temperature of the medium and the target value. Control using an algorithm such as PID control. By storing a table in which the difference between the first temperature of the medium and the target value and the rotation speed of the fan 32 are associated with each other in advance in the storage device 300, the first control unit 41 refers to this table and the fan 32. The number of rotations can also be controlled.

  The measuring unit 42 exchanges heat with the medium at the first temperature until the command unit 40 controls the operation of the heating element 10 to OFF, and the latent heat storage material 25 starts a phase change from the solid phase to the liquid phase. Measure the elapsed time. At this time, for example, by experiment or simulation, the amount of heat required for the latent heat storage material 25 of the same type and volume as the latent heat storage material 25 included in the heat storage tank 20 to start a phase change from the solid phase to the liquid phase (hereinafter referred to as the heat storage material 25 , First heat quantity) is checked and stored in the storage device 300. And based on the time history of the first temperature of the medium measured by the first measuring unit 130, the amount of heat given to the latent heat storage material 25 (hereinafter, the second amount of heat) is estimated, and the estimated second amount of heat is The time when the first heat quantity stored in the storage device 300 is reached is set as the start time of the phase change from the solid phase to the liquid phase. The measurement part 42 measures the elapsed time from this start time.

  When the latent heat storage material 25 constantly exchanges heat with the medium at the target temperature during the elapsed time measured by the measurement unit 42 and the phase change from the solid phase to the liquid phase, the determination unit 43 changes the liquid phase from the solid phase to the liquid phase. The time (first time) from the start to the end of the phase change is compared. When the elapsed time is equal to or longer than the first time, the determination unit 43 determines that the latent heat storage material 25 has finished the phase change to the liquid phase. That is, it is determined that supercooling is possible. On the other hand, when the elapsed time is shorter than the first time, it is determined that the latent heat storage material 25 has not finished the phase change to the liquid phase. That is, it is determined that supercooling is impossible. The determination unit 43 determines, for example, at the timing when the command unit 40 controls the operation of the heating element 10 to be OFF. The determination unit 43 stores the determination result in the storage device 300.

  In addition, as said 1st time, for example by experiment, simulation, etc., the latent heat storage material 25 of the same kind and the same volume as the latent heat storage material 25 which the thermal storage tank 20 contains is during the phase change from a solid phase to a liquid phase. In the case of heat exchange with the medium at the constant target temperature, the first time from the start of the phase change from the solid phase to the liquid phase until the end can be checked and stored in the storage device 300 in advance. . That is, when the latent heat storage material 25 exchanges heat with the medium having the first temperature for the first time or more on the basis of the first time, the latent heat storage material 25 is necessary for complete phase change to the liquid phase. It can be estimated that a sufficient amount of heat is stored.

  When the command unit 40 controls the operation of the heating element 10 to be ON based on an instruction from the driver, the display device 400 refers to the determination result stored in the storage device 300 and displays the determination result. That is, the driver can recognize the determination result, that is, the heat storage state of the latent heat storage material 25.

  FIG. 3 is a flowchart showing the operation of the heat storage device 1000. Here, the operation from the state in which the latent heat storage material 25 is in a solid phase is shown.

  In step 1001, the instruction unit 40 controls the operation of the heating element 10 to be ON in accordance with an instruction from the driver.

  In step 1002, the first measurement unit 130 measures the first temperature of the medium.

  In step 1003, the first control unit 41 controls the cooling unit 30 to cool the temperature of the medium when the first temperature is higher than the target temperature. When the first temperature is lower than the target temperature, the temperature of the medium is raised by the heat of the heating element 10 without cooling. Thereby, the temperature of the medium is adjusted so as to be substantially the target temperature. At this time, even if the temperature of the medium does not exactly coincide with the target temperature, it may be adjusted so as to fall within this range by, for example, determining an allowable range in advance. As an allowable range, for example, a range of target temperature ± 2 ° C. is preferable. Or it is preferable that it is a range of ± 1% in terms of the ratio to the target temperature with respect to the absolute temperature.

  The operations of Step 1002 and Step 1003 are continued until, for example, the command unit 40 controls the operation of the heating element 10 to OFF in Step 1006 described later.

  When the latent heat storage material 25 starts phase change in Step 1004, in Step 1005, the measurement unit 42 starts measuring the elapsed time from this point.

  In step 1006, when the driver finishes driving the vehicle, the instruction unit 40 controls the operation of the heating element 10 to OFF in accordance with an instruction from the driver (for example, an operation for turning off the ignition key).

  In step 1007, the measurement unit 42 ends the elapsed time measurement. The timing to end the measurement may be the same timing as step 1006, or may be the timing after step 1006 when the remaining heat of the heating element 10 is taken into account.

  In step 1008, when the latent heat storage material 25 constantly exchanges heat with the medium having the target temperature during the phase change from the solid phase to the liquid phase, the phase change from the solid phase to the liquid phase is started until the end. Is obtained from the storage device 300, and this threshold value is compared with the elapsed time.

  In Step 1009, when the elapsed time is equal to or greater than the threshold value, the determination unit 43 determines that the latent heat storage material 25 can be supercooled, and records the determination result in the storage device 300 simultaneously with the determination, for example.

  In Step 1010, when the elapsed time is smaller than the threshold value, the determination unit 43 determines that the latent heat storage material 25 is not supercooled, and records the determination result in the storage device 300 simultaneously with the determination, for example.

  In Step 1011, when the driver starts driving the vehicle, the instruction unit 40 controls the operation of the heating element 10 to ON in accordance with an instruction from the driver (for example, an operation to turn on the ignition key).

  In step 1012, the display device 400 displays the determination result stored in the storage device 300.

  According to the heat storage device 1000 of the present embodiment, the temperature of the medium that exchanges heat with the latent heat storage material is constant, so that the temperature difference between the temperature of the medium and the melting point of the latent heat storage material, and the medium and latent heat storage Since the heat transfer coefficient between the materials is constant, the temperature of the medium can be excluded from the parameters for the determination, and whether or not the latent heat storage material 25 can be supercooled based only on a simple index of elapsed time. It is possible to easily determine.

  In addition, since the temperature of the medium before passing through the heat storage tank 20 is set to a constant temperature, the latent heat storage material 25 can store heat with a constant amount of heat transfer (heat storage capacity) during the phase change. The first temperature (threshold value) can be easily set by performing experiments, simulations, and the like under the same conditions.

  When the heating element 10 is a motor and has, for example, a water jacket that penetrates the inside of the motor, the water jacket can be connected to the first circuit 101. At this time, when the medium passes through the water jacket, the heating element 10 applies heat released to the outside to the medium by heat exchange. In this case, the water jacket is used as the heat exchanger 15.

(First modification)
FIG. 4 is a block diagram showing a control device 200 according to the first modification. In the present modification, the control device 200 differs from the control device 200 of FIG. 2 in that the estimation unit 44 has a logic module.

  Based on the elapsed time measured by the measuring unit 42, the estimating unit 44 estimates the amount of heat stored after the latent heat storage material 25 exchanges heat with the medium at the target temperature and starts a phase change from the solid phase to the liquid phase. Estimate the value. For example, the estimation unit 44 estimates the heat storage amount by integrating the difference between the first temperature measured by the first measurement unit 130 and the melting point of the latent heat storage material.

  When the latent heat storage material 25 constantly exchanges heat with the medium at the target temperature between the estimated value of the heat storage amount estimated by the estimation unit 44 and the phase change from the solid phase to the liquid phase, the determination unit 43 The maximum heat storage amount that can be stored from the start to the end of the phase change from the liquid phase to the liquid phase is compared. When the estimated value of the heat storage amount is equal to or greater than the maximum value of the heat storage amount, the determination unit 43 determines that the latent heat storage material 25 has finished the phase change to the liquid phase. That is, it is determined that supercooling is possible. On the other hand, when the estimated value of the heat storage amount is smaller than the maximum value of the heat storage amount, it is determined that the latent heat storage material 25 has not finished the phase change to the liquid phase. That is, it is determined that supercooling is impossible. The determination unit 43 stores the determination result in the storage device 300.

  The maximum value of the heat storage amount is, for example, a phase change from the solid phase to the liquid phase of the latent heat storage material 25 of the same type and volume as the latent heat storage material 25 included in the heat storage tank 20 by experiment or simulation. During the heat exchange with the medium of the target temperature at all times, the maximum value of the heat storage amount that can be stored from the start to the end of the phase change from the solid phase to the liquid phase is checked, and the storage device 300 Can be stored.

  FIG. 5 is an example of a simulation result for explaining the operation of the heat storage device 1000. Consider the case where the first temperature of the medium from time T1 to time T2 is constant as shown in FIG. Further, as shown in FIG. 5B, the latent heat storage material 25 starts phase change from the solid phase to the liquid phase at time T1, and ends the phase change at time T2.

  At this time, FIG. 5C shows a time history of the amount of heat transfer from the medium to the latent heat storage material 25 from time T1 to time T2.

  According to the present modification, by setting the temperature of the medium before passing through the heat storage tank 20 to be constant, the latent heat storage material 25 can store heat with a constant amount of heat transfer during phase change. By performing experiments and simulations under the same conditions, the maximum value of the heat storage amount can be easily set. Further, in addition to a simple indicator of elapsed time, it is possible to easily determine whether the latent heat storage material 25 can be overcooled based on the temperature of the medium after the cooling unit 30 has adjusted, that is, the temperature of a certain medium. It becomes.

(Second modification)
FIG. 6 is a block diagram showing a heat storage device 1000 according to the second modification. FIG. 7 is a block diagram showing a control device 200 according to the second modification. In this modification, the heat storage device 1000 is different from the heat storage device 1000 of FIG. 2 is different from the control device 200 of FIG. 2 in that the control device 200 includes an estimation unit 44.

  Based on the elapsed time measured by the measuring unit 42, the estimating unit 44 estimates the amount of heat stored after the latent heat storage material 25 exchanges heat with the medium at the target temperature and starts a phase change from the solid phase to the liquid phase. Estimate the value. In addition, when the determination unit 43 determines that the latent heat storage material 25 is not supercooled, the estimation unit 44 is a medium having a target temperature constantly during the phase change of the latent heat storage material 25 from the solid phase to the liquid phase. When the heat exchange is performed, the maximum value of the heat storage amount that can be stored from the start of the phase change from the solid phase to the liquid phase until the end, and the estimated value of the heat storage amount at the time when the determination unit 43 determines The difference is calculated.

  The heating unit 150 is a heater provided in the vicinity of the heat storage tank 20. The heating unit 150 provides the latent heat storage material 25 with an amount of heat corresponding to the difference calculated by the estimation unit 44.

  The determination unit 43 determines that the latent heat storage material 25 can be supercooled when the heating unit 150 provides the latent heat storage material 25 with an amount of heat corresponding to the difference. The determination unit 43 stores the determination result in the storage device 300.

  According to this modification, even when the operation of the heating element 10 is stopped, even if the latent heat storage material 25 is not in a state where it can be supercooled, a sufficient amount of heat is applied to completely change the phase to the liquid phase. Can be made. That is, it can be in a state capable of supercooling.

  Here, the example in which the heating unit 150 is provided in the vicinity of the heat storage material 20 has been described. However, for example, by providing the heating unit 150 in a part of the first circuit 101, the medium is heated to indirectly heat the latent heat storage material 25. It is good also as a structure which gives.

(Second embodiment)
FIG. 8 is a block diagram showing a heat storage device 1500 according to the second embodiment. In this embodiment, the heat storage device 1500 is different from the heat storage device 1000 of FIG. 1 in that the second measurement unit 140 is provided.

  The second measurement unit 140 is a temperature sensor provided between the heat storage tank 20 and the cooling unit 30. The second measuring unit 140 measures the temperature of the medium after passing through the heat storage tank 20 and before passing through the cooling unit 30 (hereinafter referred to as second temperature) among the media passing through the first circuit 101. . That is, the second temperature of the medium after the heat is applied to the latent heat storage material 25 by heat exchange and before the temperature is cooled by the cooling unit 30 is measured.

  The measurement unit 42 measures the elapsed time from the time when the second temperature measured by the second measurement unit 140 becomes constant. That is, the second temperature of the medium after passing through the heat storage tank 20 can be approximately regarded as the temperature of the latent heat storage material 25. Therefore, the time when the second temperature becomes constant can be regarded as the time when the latent heat storage material 25 starts phase change from the solid phase to the liquid phase.

  Here, “constant” means that the absolute value of the change rate (K / s) of the second temperature falls below a predetermined threshold value. That is, the measurement unit 42 can measure the elapsed time from the time when the absolute value of the second temperature change rate (K / s) reaches the threshold value determined in advance for the first time.

  FIG. 9 is an example of a simulation result for explaining the operation of the heat storage device 1500. As shown in FIG. 9A, consider a case where the first temperature of the medium from time T1 to time T2 is constant. As shown in FIG. 9B, the latent heat storage material 25 starts phase change from the solid phase to the liquid phase at time T1, and ends the phase change at time T2.

  At this time, FIG. 9C shows the absolute value of the rate of change of the second temperature. Accordingly, it is understood that the absolute value of the change rate of the second temperature is within a threshold value (for example, 0.001) from the time T1 when the latent heat storage material 25 starts the phase change to the time T2 when the phase change ends. .

  According to the heat storage device 1500 of the present embodiment, by measuring the second temperature of the medium close to the temperature of the latent heat storage material 25 without directly measuring the temperature of the latent heat storage material 25, based on the second temperature. The timing at which the latent heat storage material 25 starts a phase change from the solid phase to the liquid phase can be grasped with high accuracy. This makes it possible to determine with high accuracy whether the latent heat storage material 25 can be supercooled based on a more accurate elapsed time.

(Third embodiment)
FIG. 10 is a block diagram showing an air conditioner 2000 according to the third embodiment. FIG. 11 is a block diagram showing the control device 200 of FIG. The air conditioner 2000 of FIG. 10 includes the heat storage device 1000 of FIG. The same components as those of the heat storage device 1000 of FIG. 1 and the control device 200 of FIG.

  10 includes a nucleation device 160, a second bypass circuit 112, and a second control valve 113. Moreover, the air-conditioning part 170, the thermal storage tank 20, and the air-conditioning part 170 are connected cyclically | annularly, and the 2nd circuit 111 for a medium to pass through is provided. The control device 200 in FIG. 11 includes the second control unit 45 as a logic module.

  The nucleation device 160 is a device for nucleating the latent heat storage material 25 by giving a trigger such as impact or voltage application to the latent heat storage material 25. The operation of the nucleation device 160 is controlled by the command unit 40 based on an instruction from a driver driving the vehicle when the storage device 300 stores that it can be supercooled.

  The second bypass circuit 112 is connected to the first circuit 101 via the second control valve 113 at the branch point C, and is connected to the first circuit 101 at the branch point D, thereby bypassing the heat storage tank 20.

  The second control valve 113 switches the flow path of the medium that has passed through the first circuit 101 and reached the second control valve 113 to either the first circuit 101 or the second bypass circuit 112. Here, the state of switching (or maintaining) the medium flow path to the first circuit 101 is “second control valve: OFF”, and the state of switching (or maintaining) the medium flow path to the second bypass circuit 112 is “ It is defined as “second control valve: ON”.

  The air conditioning unit 170 adjusts the air temperature or humidity in the vehicle. Here, as the air conditioning unit 170, a general heat pump system including a compressor, a condenser, an evaporator, and the like is used, and detailed description thereof is omitted.

  The second control unit 45 controls the switching of the second control valve 113 to be ON at the timing when the command unit 40 controls the nucleation device 160. As a result, the heat of the latent heat storage material 25 that releases heat by nucleating does not transfer to the medium of the first circuit 101, so that heat can be efficiently transferred to the medium of the second circuit 111. it can.

  The air conditioning unit 170 may be a seat, a handle, or the like through which the second circuit 111 passes. In this case, the high-temperature medium passing through the second circuit can directly warm the seat, the handle, and the like.

  According to the heat storage device, the air conditioner, and the heat storage method according to at least one embodiment described above, it is possible to determine with high accuracy whether or not the latent heat storage material can be supercooled.

  These embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention and are also included in the invention described in the claims and the equivalents thereof.

DESCRIPTION OF SYMBOLS 10 ... Heat generating body 20 ... Thermal storage tank 30 ... Cooling part 31 ... Radiator 32 ... Fan 40 ... Command part 41 ... 1st control part 42 ... Measurement part 43- ··· Determination unit 44 ··· Estimation unit 45 ··· Second control unit 101 ··· First circuit 102 ··· First bypass circuit 103 · · · First control valve 111 · · · Second circuit 112 · · · .... Second bypass circuit 113 ... second control valve 130 ... first measurement unit 140 ... second measurement unit 150 ... heating unit 160 ... nucleation device 170 ... air conditioning unit 200 ... Control device 300 ... Storage device 400 ... Display device 1000, 1500 ... Heat storage device 2000 ... Air conditioner

Claims (10)

In a heat storage device that stores heat released from a heating element through a medium,
A closed first circuit for circulating the medium in one direction;
A heat exchanger provided in a part of the first circuit for exchanging heat with the medium from the heat generated by the heating element;
A heat storage tank including a latent heat storage material that is provided downstream of the heat exchanger of the first circuit in a direction in which the medium circulates and exchanges heat with the medium that has obtained heat released from the heating element; ,
A first measuring unit for measuring a temperature of the medium passing between the heat exchanger and the heat storage tank;
When the temperature of the medium measured by the first measurement unit is higher than a predetermined target temperature, the medium is cooled, and the temperature of the medium passing between the heat exchanger and the heat storage tank is set to the target temperature. A cooling section approximately equal to
A measuring unit that measures an elapsed time after the latent heat storage material starts a phase change from a solid phase to a liquid phase by exchanging heat with the medium;
Based on the elapsed time, a determination unit that determines whether the latent heat storage material can be supercooled, and
A heat storage device comprising: A storage unit that stores a first time from when the latent heat storage material starts the phase change to when it ends when heat exchange is performed with the target temperature medium;
The heat storage device according to claim 1, wherein the determination unit determines whether or not the latent heat storage material can be supercooled by comparing the first time and the elapsed time. A storage unit that stores a first heat storage amount that can be stored from the start of the phase change to the end of the latent heat storage material when heat exchange is performed with the target temperature medium;
Using the temperature of the medium measured by the first measurement unit and the elapsed time, and an estimation unit that estimates an estimated value of the heat storage amount stored after the latent heat storage material starts the phase change,
The heat storage device according to claim 1, wherein the determination unit compares the first heat storage amount and an estimated value of the heat storage amount to determine whether the latent heat storage material can be supercooled. A second measuring unit for measuring a second temperature of the medium after passing through the heat storage tank;
The heat storage device according to any one of claims 1 to 3, wherein the measurement unit measures an elapsed time from a time when the second temperature becomes constant. A heating unit for applying heat to the latent heat storage material;
The heat storage device according to any one of claims 1 to 4, wherein the heating unit heats the latent heat storage material or the medium when the determination unit determines that the latent heat storage material cannot be supercooled. The cooling unit includes a radiator connected to the first circuit, and a fan facing the radiator,
The heat storage device according to any one of claims 1 to 5, further comprising a first control unit that controls a rotation speed of the fan. The cooling unit is connected to the first circuit at a first branch point and bypasses the radiator, and the flow path of the medium at the first branch point is the first circuit or the first bypass. A first control valve switchable to any of the circuits,
The heat storage device according to any one of claims 1 to 6, further comprising a first control unit that controls switching of the first control valve.   The heat storage device according to claim 1, wherein the heating element is at least one of a motor, an inverter, and a battery. An air conditioner comprising the heat storage device according to any one of claims 1 to 8,
A nucleation device for nucleating the latent heat storage material;
A second bypass circuit connected to the first circuit at a second branch point and bypassing the heat storage tank;
A second control valve capable of switching the flow path of the medium to either the first circuit or the second bypass circuit at the second branch point;
A second control unit that controls switching of the second control valve and switches the flow path of the medium to the second bypass circuit when the determination unit determines that the latent heat storage material can be supercooled;
An air conditioner. Medium,
A closed first circuit for circulating the medium in one direction;
A heat exchanger provided in a part of the first circuit for exchanging heat released from the heating element with the medium;
A heat storage tank including a latent heat storage material that is provided downstream of the heat exchanger of the first circuit in the direction in which the medium circulates and exchanges heat with the medium that has obtained heat released by the heating element;
A heat storage method in a heat storage device or an air conditioner comprising:
A first step of circulating the medium;
A second step of measuring the temperature of the medium passing between the heat exchanger and the heat storage tank;
When the temperature of the medium measured in the second step is higher than a predetermined target temperature, the medium is cooled, and the temperature of the medium passing between the heat exchanger and the heat storage tank is set to the target temperature. A third step that is approximately equal;
A fourth step of measuring an elapsed time after the latent heat storage material exchanges heat with the medium and starts a phase change from a solid phase to a liquid phase;
A determination unit that determines whether the latent heat storage material can be supercooled based on the elapsed time; and
A heat storage method.