JP4388596B2 - Thermal storage system and thermal storage method - Google Patents

Description

  The present invention relates to a heat storage system and a heat storage method.

A heat storage system for storing thermal energy has been effective as an energy saving technique. In recent years, hot water supply equipment using a CO ₂ heat pump or a fuel cell cogeneration system has attracted attention, but the development of high-density heat storage technology has been awaited in order to downsize these equipment and improve installation. ing.

  Conventional heat storage technologies are roughly classified into sensible heat storage, latent heat storage, and chemical heat storage. Among them, according to sensible heat storage and latent heat storage, although losses such as heat exchange loss occur in practice, theoretically, an amount of heat equivalent to the amount of heat input at the time of heat storage can be taken out when necessary.

  Sensible heat storage and latent heat storage are distinguished by the type of heat storage material used in the heat storage section. The latent heat storage material used for latent heat storage has a higher heat storage density and a constant phase change temperature than the sensible heat storage material. Therefore, there is an advantage that the heat extraction temperature is stable. Taking advantage of this advantage, heat storage systems using various latent heat storage materials have been put into practical use. Conventionally, as disclosed in Patent Document 1, a heat storage device that once stores heat of a heat source unit in a heat storage unit of a heat medium circuit and supplies the heat of the heat storage unit to a user side through the heat medium is generally used. Known. In this heat storage system, for example, a heat exchange unit is provided in a heat storage unit filled with a latent heat storage material, and water as a heat medium is passed through a heat transfer tube of the heat exchange unit. The water heated by the latent heat storage material in this way is supplied to the use side and used for a water heater or the like. Further, as disclosed in Patent Document 1, since the heat conductivity of the latent heat storage material is low, a fin-and-tube heat exchange part is formed in the heat storage part, and the performance is improved by enlarging the heat transfer surface. Can be made.

  FIG. 11 is a diagram illustrating a configuration of a conventional heat storage system using a heat pump circuit. The heat storage system shown in FIG. 11 includes a refrigerant circuit 10 having a compressor 6, a second heat exchanger 9, an expansion device 8, and an evaporator 7, and a heat storage container 2 that houses the second heat exchanger 9 and the latent heat storage material 3. And a heat medium circuit 50 that circulates the heat medium between the heat storage unit 1 and the heat storage unit 1. The heat storage unit 1 includes a heat exchange unit 4 for performing heat exchange between the heat medium and the latent heat storage material 3 and fins 5 for enlarging the heat transfer surface of the heat exchange unit 4.

  In the heat storage system of FIG. 11, the heat source unit is configured by the refrigerant circuit 10 that performs the heat pump cycle. The heat medium is heated by exchanging heat between the refrigerant in the refrigerant circuit 10 and the heat medium in the heat medium circuit 50 in the second heat exchange unit 9. The heated heat medium is heat exchanged with the heat storage material 3 in the first heat exchange unit 4. Thereby, the heat of the heat source part can be stored in the heat storage material 3. The stored heat is used in a heat recovery device such as a water heater. In this system, the heat storage material 3 in the heat storage state and the city water are subjected to heat exchange, and the obtained water (hot water) is taken out from the hot water inlet 12 and used.

  On the other hand, a heat storage system using chemical heat storage has also been proposed. Chemical heat storage is a heat storage technology that uses reaction heat from reversible chemical reactions. Chemical heat storage includes an adsorption system, a hydrogen storage alloy system, an organic reaction system, and an inorganic reaction system depending on the chemical reaction used. Since the chemical heat storage system is accompanied by chemical changes such as adsorption and hydration of substances, the heat storage density per unit mass is higher than the heat storage method using sensible heat or latent heat of the heat storage material itself. However, the chemical heat storage system uses a gas-liquid reaction or a gas-solid reaction regardless of any of the above chemical reactions, and if stored in the form of a gas, the volume of the stored gas is extremely large, so the heat storage density is high. It becomes quite low. On the other hand, it has been proposed to reduce the volume of the system by condensing or converting the gas generated during heat storage into a solid compound such as condensation or metal hydride, but the heat (generated heat) generated by condensation or conversion is reduced. I'm escaping to the open air. For this reason, when heat is used, that is, in the heat dissipation process, gas is generated from a liquid or solid compound to cause a reaction opposite to that during heat storage.

  For example, in Patent Document 2, in a chemical heat storage system using a reaction in which a solid inorganic anhydride and water vapor react to produce a solid hydrate, heat generated by condensation of gaseous water vapor during heat storage (condensation) A method has been proposed in which the reduction of COP is suppressed by recovering (heat) into a heat pump that is a heat source for heat storage.

  Patent Document 3 discloses that in a chemical heat storage system using a reaction in which a solid inorganic anhydride reacts with water vapor to produce a solid hydrate, water vapor generated from the solid hydrate during heat storage is obtained. It is disclosed to recover and react with a solid inorganic anhydride during heat dissipation.

  Further, in Patent Document 4, in a heat storage method using an inorganic salt hydrate as a heat storage material and using a heat pump circuit as a heat source, it is included in the heat storage material from a container that stores the heat storage material during heat storage. It is disclosed that the water stored in the water tank is taken out and the water in the water tank is reacted with the heat storage material at the time of heat radiation. In addition, it has also been proposed to react with the heat storage material after heating the water in the water tank during heat dissipation.

  In this specification, the heat energy (heat amount) that can be substantially stored in the heat cycle including the heat storage process and the heat release process is “heat storage amount”, and the heat storage amount per unit volume (or unit weight) of the heat storage material amount is “ It is called “heat storage density”.

JP 2001-207163 A Japanese Patent Publication No. 7-6708 Japanese Patent No. 1568780 International Publication No. 2007/102374 Pamphlet

  In a conventional heat storage system using a heat pump circuit, there is a problem that a coefficient of performance (COP: Coefficient of Performance, hereinafter referred to as “COP”) of the heat pump cycle decreases during the heat storage operation. The heat storage system disclosed in Patent Document 1 (FIG. 11) will be described as an example. When the temperature of the heat storage unit 1 increases during heat storage, the temperature of the heat medium after heat exchange with the heat storage unit 1 also increases. As a result, the amount of heat exchanged in the second heat exchange unit 9 is reduced.

  On the other hand, conventionally, in order to prevent the system from operating at a low COP, the temperature of the heat medium before being heated by the second heat exchange unit 9 after the heat exchange with the heat storage unit 1 is 60 ° C. When it reached, the heat storage operation was completed. For this reason, it was difficult to make the temperature of the heat storage material 3 higher than 60 ° C., and it was difficult to increase the heat storage amount.

  Here, the reason why COP decreases with time during heat storage will be described in detail with reference to the drawings. FIGS. 12A and 12B are conceptual diagrams showing the temperatures of the heat storage material and the refrigerant at the initial stage during heat storage and after a predetermined time has elapsed. As shown in FIG. 12 (a), the difference between the temperature of the refrigerant (refrigerant inlet temperature) flowing into the second heat exchange unit 9 and the temperature of the heat storage unit 1 is large at the initial stage of heat storage. For this reason, the amount of heat exchange in the second heat exchange unit 9 increases, and the temperature of the refrigerant flowing out of the second heat exchange unit 9 (the refrigerant outlet temperature) is sufficiently lower than the inlet temperature. However, as time passes, as shown in FIG. 12B, the temperature of the heat storage unit 1 rises and the temperature of the heat medium increases, so that the amount of heat exchange in the second heat exchange unit 9 decreases, and the refrigerant The outlet temperature rises.

FIGS. 13A and 13B are Mollier diagrams of the heat pump cycle at the initial stage during heat storage and after a predetermined time has elapsed, respectively. As can be seen from FIGS. 13A and 13B, as the time elapses, the outlet temperature of the refrigerant rises, so that h ₂ −h ₃ representing the heat exchange amount in the second heat exchange unit 9 becomes smaller. . As a result, h ₂ −h ₃ / h ₂ −h ₁ representing the COP of the heat pump cycle is lowered.

  On the other hand, according to the heat storage system of patent document 2, COP of a refrigerant circuit can be improved by collect | recovering condensed heat to the heat pump which is a heat source of heat storage. However, even if the heat of condensation is recovered, a decrease in COP due to suppression of heat exchange between the heat source and the heat storage unit due to the temperature increase of the heat medium accompanying heating of the heat storage unit is inevitable.

  Furthermore, according to the heat storage system of Patent Document 3, since the temperature of water (condensed water) supplied to the heat storage unit at the time of heat radiation is low, the amount of heat that can be taken out and used during the heat radiation operation (the amount of heat extracted (heat radiation amount)) is reduced. There is also a problem of end. In addition, since the heat storage system of patent document 3 does not utilize a heat pump circuit, there is no description regarding the means which suppresses a COP fall.

  Patent Document 4 describes that when heat is released, the water in the water tank is heated and then reacted with the heat storage material, whereby the amount of extracted heat (heat dissipation) can be increased. Therefore, it is possible to efficiently extract the heat stored in the heat storage material. However, Patent Document 4 does not describe any means for suppressing a decrease in COP that accompanies an increase in the temperature of the heat storage material during heat storage.

  Thus, according to the conventional heat storage system, the COP of the heat pump cycle decreases with the passage of time during heat storage, and the efficiency of the system decreases. On the other hand, when attempting to operate while suppressing a decrease in the efficiency of the system, it is difficult to increase the amount of heat storage.

  The present invention has been made in view of the above circumstances, and its purpose is to use a heat storage material that stores heat by a dehydration reaction and dissipates heat by a water absorption reaction, and has a high efficiency and a large amount of heat storage. It is to provide a heat storage method.

  The heat storage method of the present invention is a heat storage method using a heat storage material that stores heat by desorbing water and releases heat by reacting with water, and (a) the heat storage material contained in the heat storage material container A first heat storage step of heating the heat storage material and taking out water detached from the heat storage material from the heat storage material container and storing it in a water reservoir; and (b) between the heat storage material container and the water reservoir. And (c) in the blocked state, further heating the heat storage material to further increase the temperature of the heat storage material and storing it in the water reservoir. A second heat storage step for heating the desorbed water, and (d) a heat release step for supplying the heated water to the heat storage material container and causing the desorbed water and the heat storage material to react with each other. including.

  According to the heat storage method of the present invention, the second heat storage process is performed in a state where the movement of water is blocked between the heat storage material container and the water reservoir during the heat storage operation. With the second heat storage step, the temperature of the heat storage material can be increased to a higher temperature with the same heat source, and the amount of heat storage can be increased.

  Moreover, since the movement of water is interrupted | blocked between a thermal storage material container and a water reservoir in a 2nd thermal storage process, even if it heats the water taken out from the thermal storage material container, the heated water is the thermal storage material container. It is possible to prevent backflow into the inside. Therefore, it is possible to suppress a decrease in the heat storage amount due to the backflow of water.

  Furthermore, since the heated water and the heat storage material are reacted in the heat dissipation step, the heat storage material in the heat storage state can be reacted with higher temperature water. For this reason, it can suppress that taking-out calorie | heat amount reduces because the temperature of the water to react is low.

  Accordingly, the amount of stored heat can be increased as compared with the conventional case, and the stored heat can be efficiently extracted.

  The heat storage system of the present invention is a heat storage system that stores heat by desorbing water from the heat storage material, and dissipates heat by reacting the desorbed water with the heat storage material, and houses the heat storage material. A heat storage material container; a heat storage material heating unit that heats the heat storage material during a heat storage operation; a water reservoir that stores water desorbed from the heat storage material by heating the heat storage material; and the desorbed water A water transport path for moving the heat storage material container from the heat storage material container to the water reservoir, a condensing part provided in the water transport path for condensing the desorbed water, provided in the water transport path, and the heat storage material container A valve that restricts movement of the desorbed water between the water reservoir and the stored water heating unit that heats the desorbed water stored in the water reservoir, Desorbed water from the water reservoir is stored in the heat A water supply path for supplying water to the container, and the valve is switched from an open state to a closed state in the middle of the heat storage operation. Heat the released water.

  According to the heat storage system of the present invention, the valve that restricts the movement of water between the heat storage material container and the water reservoir is closed during the heat storage operation, so that the temperature of the heat storage material can be further increased with the same heat source. It becomes possible to raise to a high temperature, and heat storage amount can be raised. Moreover, when the water taken out from the heat storage material container is heated, the heated water can be prevented from flowing back into the heat storage material container. Therefore, at the time of heat storage operation, it is possible to suppress a decrease in the amount of stored heat due to heat dissipation by reacting with the heat storage material and water.

  Furthermore, the water heated by the stored water heating part and the heat storage material can be reacted during the heat radiation operation. For this reason, since it becomes possible to make the thermal storage material of a thermal storage state react with higher temperature water, it can suppress that the taking-out heat amount reduces by the temperature of the water made to react at the time of heat radiation operation.

  In a preferred embodiment, the heat storage material heating unit includes a compressor, a heat radiator, an expansion device, an evaporator, and a heat pump circuit including a refrigerant path for circulating the refrigerant therebetween, and is heated by the heat radiator, and the heat storage A heat medium path for circulating a heat medium (water) to be cooled by heat exchange with the material, and the condensing part is desorbed by heat exchange with the refrigerant of the heat pump circuit The water storage unit is configured to cool water, and the stored water heating unit is heated by the radiator after heat exchange with the desorbed water stored in the water storage device and the heat storage material. A stored water / heat medium heat exchanging unit that exchanges heat with the heat medium before being heated.

  According to such a configuration, after the valve is closed during the heat storage operation, the temperature of the heat medium flowing into the heat radiator of the heat pump circuit can be lowered using the water stored in the water reservoir. it can. Therefore, it can suppress that the temperature of a heat medium rises as heat storage progresses. As a result, even if the temperature of the heat storage material rises, the amount of heat exchange between the refrigerant and the heat medium in the radiator can be ensured, so that a reduction in COP of the heat pump cycle can be suppressed. Further, it is possible to heat the heat storage material to a higher temperature than before while suppressing a decrease in COP, and as a result, a heat storage system with high efficiency and a large amount of heat storage can be realized.

  According to the present invention, the temperature of the heat storage material can be raised to a higher temperature, so that the amount of heat storage can be increased. Moreover, since it can prevent that the water taken out from the thermal storage material container flows backward into the thermal storage material container and reacts with the thermal storage material during the thermal storage operation, it is possible to suppress a decrease in the amount of stored heat caused by the backward flow of water. Furthermore, since the heat storage material can be reacted with hotter water during heat dissipation, the stored heat can be efficiently recovered. Therefore, the efficiency of the heat storage system can be greatly improved.

  When a heat pump circuit is provided as a heat source, it is preferable to provide a stored water / heat medium heat exchange unit as the stored water heating unit. Thereby, at the time of heat storage operation, the temperature of the heat medium before being heated by the radiator of the heat pump circuit can be kept low, so that the heat storage material can be heated to a higher temperature than before while suppressing the decrease in COP of the heat pump cycle. It becomes possible to heat. Therefore, it is possible to realize a heat storage system with higher efficiency and a large amount of heat storage.

It is a block diagram of the heat storage system of Embodiment 1 of this invention. It is a graph which illustrates the relationship between the temperature of the thermal storage material at the time of thermal storage operation, and salt concentration in the thermal storage system of Embodiment 1. (A)-(c) is a graph which illustrates the relationship between the elapsed time from the start of a thermal storage operation, the salt concentration of a thermal storage material, the temperature Tm of a heat medium, and the temperature of a thermal storage material in Embodiment 1, respectively. . (A)-(c) is a graph which each illustrates the relationship between the elapsed time from the start of thermal storage operation, the salt concentration of a thermal storage material, the temperature of a heat medium, and the temperature of a thermal storage material in the conventional thermal storage method. . It is a graph for comparing the amount of extracted heat in Embodiment 1 with the amount of extracted heat in a conventional heat storage method. It is a block diagram of the heat storage system of Embodiment 2 of this invention. In the thermal storage system of Embodiment 2, it is a graph which illustrates the relationship between the temperature of a thermal storage material at the time of thermal storage operation, and salt concentration. It is a graph which illustrates the relationship between the pressure and temperature in a thermal storage material container, and the salt concentration of a thermal storage material. (A)-(c) is a graph which illustrates the relationship between the elapsed time from the start of a thermal storage operation, the salt concentration of a thermal storage material, the temperature Tm of a heat medium, and the temperature of a thermal storage material in Embodiment 2, respectively. . It is a block diagram of the thermal storage system of Embodiment 3 of this invention. It is a block diagram of the conventional heat storage system provided with the fin and tube type heat exchanger. (A) And (b) is a conceptual diagram which shows the temperature of the thermal storage material and refrigerant | coolant after the initial stage at the time of thermal storage, and predetermined time progress. (A) And (b) is the Mollier diagram of the heat pump cycle after the initial stage at the time of thermal storage and predetermined time, respectively.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1)
Hereinafter, a first embodiment of a heat storage system according to the present invention will be described with reference to the drawings.

  FIG. 1 is a configuration diagram of the heat storage system of the present embodiment. In the present embodiment, a heat storage material that stores heat by a dehydration reaction and radiates heat by a water absorption reaction is used as the heat storage material.

<Configuration of heat storage system>
The heat storage system of the present embodiment is removed from the heat storage material 3 by heating the heat storage material 1, the heat storage material container 2 that houses the heat storage material 3, the heat storage material heating unit that heats the heat storage material 3, and the heat storage material 3. The water recovery unit 11 that stores the separated water, the water discharge path 43 that moves the water desorbed from the heat storage material 3 from the heat storage material container 2 to the water recovery unit 11, and the water stored in the water recovery unit 11 The storage water heating part 44 to heat and the water supply path 45 which supplies the water stored in the water collection | recovery part 11 to the thermal storage material container 2 at the time of heat dissipation operation are provided.

  In this embodiment, the heat storage material container 2 is laminated. Moreover, in the heat storage material container 2, the 1st heat exchange part 4 which heat-exchanges the heat storage material 3 and the heat medium of the heat medium path | route 42, and the heat transfer performance from a heat medium to the heat storage material 3 are improved. The water 5 connected to the fin 5 and the water supply path 45 and supplying water to the heat storage material 3 at the time of heat dissipation and the water discharge path 43 connected to the water discharge path 43 and the water desorbed from the heat storage material 3 at the time of heat storage are stored in the heat storage material container 2. And a water vapor pipe 13 for discharging from the water.

  As the heat storage material 3, at least one compound selected from the group consisting of chloride, bromide, iodide, hydroxide, nitrate, sulfate, thiosulfate, phosphorus oxide, borate and acetate is used. The latent heat storage material can be used. For example, calcium chloride hydrate, calcium bromide hydrate, or the like may be used. Here, calcium chloride hexahydrate is used.

As can be seen from the following formula (1), when calcium chloride hexahydrate is heated, it undergoes a dehydration reaction to become calcium chloride tetrahydrate and stores heat (ΔH) (rightward reaction). On the other hand, calcium chloride tetrahydrate reacts with water to become calcium chloride hexahydrate and releases heat (ΔH) (reaction facing left). In this specification, the state where heat is stored (here, calcium chloride tetrahydrate) is simply “heat storage state”, and the state after heat dissipation (here, calcium chloride · hexahydrate) is simply “heat dissipation state”. "
CaCl ₂ · 6H ₂ O + ΔH Ｃａ CaCl ₂ · 4H ₂ O + 2H ₂ O (1)

  The heat storage material heating unit in the present embodiment includes a heat pump circuit 10 and a heat medium path 42 that circulates the heat medium so as to be cooled by heat exchange with the heat storage material 3 by being heated by the refrigerant of the heat pump circuit 10. Prepare.

  The heat pump circuit 10 includes a compressor 6 that compresses the refrigerant, a heat medium heating unit (third heat exchange unit) 39 that exchanges heat between the refrigerant compressed by the compressor 6 and the heat medium in the heat medium path 42, and a heat medium. An expansion valve 8 that expands the refrigerant after heat exchange with the first evaporator 7, a first evaporator 7 that heats the expanded refrigerant, and a refrigerant path that circulates the refrigerant between them. Further, a water condensing unit 46 is provided between the first evaporator 7 and the compressor 6 to cool the water discharged from the heat storage unit 1 by exchanging heat with the refrigerant. Here, the water condensing unit (also referred to as a second evaporator) 46 is configured to exchange heat between the refrigerant heated by the first evaporator 7 and the water discharged from the heat storage unit 1. Is included.

  The heat medium path 42 includes a heat medium heating part 39 of the heat pump circuit 10, the first heat exchange part 4 of the heat storage part 1, and a heat medium path for circulating the heat medium therebetween. For example, water may be used as the heat medium. Further, in the heat medium path 42, heat exchange between the heat medium cooled by the first heat exchanging unit 4 and before being heated by the heat medium heating unit 39 and water stored in the water recovery unit 11 is performed. The 2nd heat exchange part 9 which performs is provided. The heat medium path 42 may be further connected to the water supply port 41 and the hot water supply port 12. In this case, at the time of heat radiation, the heat medium (water) supplied from the water supply port 41 is heated by exchanging heat with the heat storage material 3 in the heat storage state in the first heat exchange unit 4, and the obtained hot water is supplied to the hot water supply port 12. It may be configured to transport to.

  The water discharge path 43 connects the steam pipe 13 of the heat storage unit 1 and the water recovery unit 11. The water (water vapor) desorbed from the heat storage material 3 is discharged from the heat storage material container 2 and then transported to the condenser 14 through the water discharge path 43, where it is condensed into liquid water. The liquid water is transported to the water reservoir 16 where it is stored. Further, the water discharge path 43 is provided with a valve 24 that restricts the movement of water between the heat storage material container 2 and the water reservoir 16.

  The stored water heating unit 44 is stored in the water storage unit 16 of the water recovery unit 11, the second heat exchange unit (also referred to as stored water / heat medium heat exchange unit) 9, and the water storage unit 16 between them. And a storage water path for circulating the water that has been stored. With such a configuration, the water stored in the water reservoir 16 is heated by exchanging heat with the heat medium in the heat medium path 42 in the second heat exchange unit 9 and then returned to the water reservoir 16. . In the illustrated example, the stored water is circulated and heat exchange with the heat medium is performed. However, the stored water is retained in the water reservoir 16 by switching the heat medium path 42. It may be configured to exchange heat with the heat medium.

  The water supply path 45 connects the water recovery unit 11 and the water spray unit 40 of the heat storage unit 1. The water recovered by the water recovery unit 11 during heat storage is transported to the water spray unit 40 of the heat storage unit 1 through the water supply path 45 during heat dissipation, and is supplied to the heat storage material container 2 by the water spray unit 40.

<Heat storage operation>
Next, the operation | movement at the time of the thermal storage driving | operation of the thermal storage system of this embodiment is demonstrated.

  In the present embodiment, the heat storage material 3 is heated with the valve 24 opened, and the water desorbed from the heat storage material 3 is taken out from the heat storage material container 2 and stored in the water recovery unit 11 (hereinafter referred to as “first” The heat storage process. Subsequently, by closing the valve 24, the movement of water between the heat storage material container 2 and the water recovery unit 11 is blocked. In this state, the heat storage material 3 is further heated to further increase the temperature of the heat storage material 3, and the water stored in the water recovery unit 11 is heated (hereinafter referred to as “second heat storage step”). In this way, the heat storage process is performed in two stages.

  Hereinafter, the operation of each heat storage process will be described in more detail with reference to the drawings.

  FIG. 2 is a graph illustrating the relationship between the temperature of the heat storage material and the salt concentration during the heat storage operation. The curve (A) shown in FIG. 2 corresponds to the first heat storage process, and the straight line (B) corresponds to the second heat storage process.

  First, before starting the first heat storage step, all the valves 22 to 24, 26, 28, 30, and 32 to 35 are closed. Next, the valve 23 and the valve 24 are opened, and the pressure of the heat storage unit 1 and the condenser 14 is lowered by the vacuum pump 21. When the pressure in the heat storage unit 1 and the condenser 14 is reduced to a predetermined value, the valve 23 is closed.

  Subsequently, the first heat storage process is started. Here, the heat storage unit 1 is heated to, for example, 60 ° C. by the heat pump circuit 10. At this time, the latent heat storage material 3, which is a hydrate, undergoes a phase change from a solid to a liquid, and subsequently the hydration number begins to decrease due to concentration. The moisture desorbed from the latent heat storage material 3 becomes water vapor and is cooled by the condenser 14 through the water vapor pipe 13. The condensed water generated by the condenser 14 is stored in the water reservoir 16. In addition, it is preferable to provide the condenser 14 between the suction side of the compressor 6 and the first evaporator 7 in the water discharge path 43 as in the present embodiment because the COP of the heat pump circuit 10 can be improved.

  In the first heat storage step, as shown by the curve (A) in FIG. 2, the temperature of the heat storage material 3 rises to 60 ° C., and the salt concentration in the heat storage material 3 increases to 60%. In this step, the sensible heat for raising the temperature of the heat storage material 3 to the phase change temperature, the latent heat of fusion of the heat storage material at the phase change temperature, and the temperature of the heat storage material 3 in a solid-liquid coexistence state are raised from the phase change temperature to 60 ° C. Therefore, it is possible to store sensible heat and reaction heat due to a dehydration reaction of the heat storage material 3. Further, in the first heat storage step, the temperature Tm of the heat medium before being heated by the heat medium heating unit 39 after being cooled by the heat storage material 3 increases as the temperature of the heat storage material 3 increases.

  Thereafter, the valve 24 is closed to block the movement of water between the heat storage material container 2 and the water recovery unit 11. Thereby, a 1st heat storage process is complete | finished.

  The valve 24 is switched from the open state to the closed state when the temperature Tm of the heat medium before being heated by the heat medium heating unit 39 after being cooled by the heat storage material 3 becomes equal to or higher than a predetermined temperature (for example, 60 ° C.). It is preferred that For example, a temperature measurement unit 52 that measures the temperature of the heat medium is provided between the first heat exchanger 4 and the heat medium heating unit 39 in the heat medium path 42, and the temperature measured by the temperature measurement unit 52 is a predetermined temperature. When it is detected that the value has been reached, the valve 24 can be controlled to close.

  Instead, a water level meter is provided in the water reservoir 16 or a flow meter is provided in the water discharge path 43 so that the valve 24 is closed when the amount of water taken out from the heat storage material container 2 reaches a certain amount. It may be. Alternatively, the valve 24 may be closed when a predetermined time elapses after the first heat storage step is started.

  Then, a 2nd heat storage process is performed. With the valve 24 closed, the heat storage material 3 is further heated, and at the same time, an operation of exchanging heat between the heat medium and the water stored in the water reservoir 16 is performed.

  In the second heat storage step, first, the valve 30 attached to the water reservoir 16 is opened to increase the pressure of the water reservoir 16 to atmospheric pressure. Next, the valve 26 and the valve 28 are opened, and the water in the water reservoir 16 is sent to the second heat exchange unit 9 by the pump 19. In the second heat exchange unit 9, the heat medium after flowing through the heat storage unit 1 and the water stored in the water reservoir 16 are subjected to heat exchange, and the temperature Tm of the heat medium is lowered and the stored water is removed. Can be heated. The heated water is returned to the water reservoir 16 again.

  When the second heat storage step ends, all the valves are closed and heating of the heat storage material 3 is stopped. Also in the second heat storage step, the temperature Tm of the heat medium may be measured, and the second heat storage step may be terminated when the measured temperature reaches a second predetermined temperature (for example, 60 ° C.).

  In the second heat storage step in the present embodiment, the heat storage material 3 is heated with the valve 24 closed, that is, without taking out water from the heat storage material container 2. The heat storage material 3 can be heated, for example, until the temperature Tm of the heat medium rises to 60 ° C. again. For this reason, as shown in the straight line (B) of FIG. 2, the salt concentration of the heat storage material 3 remains constant, and the temperature of the heat storage material 3 is increased to a temperature higher than the first heat storage step (for example, 80 ° C.). be able to. As can be seen from FIG. 2, the heat storage material 3 in the heat storage state in the present embodiment is in a solid-liquid coexistence state.

  On the other hand, in the prior art, as shown by the broken line in FIG. 2, the heat storage operation is performed while taking out water from the heat storage material container, and the heat storage operation is terminated when the removal of water is stopped. Therefore, according to the present embodiment, it is possible to increase the amount of heat storage by at least the amount of sensible heat for raising the temperature of the heat storage material 3 from 60 ° C. to 80 ° C., as compared with the prior art.

  Furthermore, in this embodiment, since the stored water is heated with the valve 24 closed, the following advantages can be obtained as compared with the case of heating with the valve 24 open.

  When the stored water is heated with the valve 24 opened during heat storage, the temperature of the water in the water reservoir 16 increases, so that the vapor pressure in the water reservoir 16 rises and the vapor pressure in the heat storage material container 2 increases. It will be higher than. For this reason, the backflow of water (water vapor) in the water reservoir 16 may occur. When water flows back to the heat storage material container 2 during heat storage, the backflowed water reacts with the heat storage material 3 to dissipate heat, which may cause a decrease in the heat storage amount. On the other hand, in this embodiment, since the stored water is heated in a state where the valve 24 is closed, it is possible to suppress a decrease in the heat storage amount due to the backflow of the stored water.

  Here, changes in the salt concentration of the heat storage material 3, the temperature of the heat storage material 3, and the temperature Tm of the heat medium in each heat storage process will be described in more detail with reference to the drawings.

  3A to 3C are graphs illustrating the relationship between the elapsed time from the start of the heat storage operation, the salt concentration of the heat storage material 3, the temperature Tm of the heat medium, and the temperature of the heat storage material 3, respectively. 3 (a) to 3 (c), the time from the start of heat storage to the time when concentration of the heat storage material is completed (concentration completion time) t corresponds to the first heat storage process, and heating of the heat storage material is completed from the concentration completion time t. The time until the time (heat storage completion time) t1 corresponds to the second heat storage step. Note that the temperature Tm of the heat medium flows into the heat medium heating unit 39 after passing through the second heat exchange unit 9 when heat exchange between the heat medium and the stored water is performed (second heat storage step). It shall refer to the temperature of the previous heating medium.

  As can be seen from FIG. 3B, the temperature Tm of the heat medium flowing into the heat medium heating part (heat radiation part of the heat pump circuit) 39 is lowered (for example, 60 ° C.) by performing heat exchange between the heat medium and the stored water. Since the temperature Tm of the heat medium is increased, the COP can be prevented from decreasing. In particular, as described above, when detecting that the temperature Tm of the heat medium has reached a predetermined temperature and closing the valve 24, it is possible to more effectively suppress the decrease in COP in the subsequent heat storage step.

  Although the heat storage completion time t1 is not particularly limited, in order to operate the system with high efficiency while suppressing the decrease in COP, as shown in the figure, the temperature Tm of the heat medium is a predetermined temperature (for example, 60 ° C. or higher and 65 ° C. or lower, Then, it is preferable to complete the heat storage when the temperature reaches 60 ° C.

  For comparison, the elapsed time from the start of the heat storage operation, the salt concentration of the heat storage material, and the heat medium in the conventional heat storage methods disclosed in Patent Documents 3 and 4, for example, in FIGS. The relationship between the temperature Tm and the temperature of the heat storage material is illustrated.

  In the heat storage methods disclosed in Patent Documents 3 and 4, during the heat storage operation, the heat storage material is heated while taking out the water desorbed from the heat storage material, and when the heat storage operation ends, the extraction of water from the heat storage material container is stopped. To do. Therefore, as shown in FIG. 4, the concentration completion time t is equal to the heat storage completion time t1.

  As described above, in the conventional heat storage method, when the temperature of the heat medium reaches 60 ° C., the COP becomes too low and the heat storage operation is terminated. Therefore, as can be seen from FIG. 4C, the heat storage completion time t1 is the time when the temperature of the heat medium reaches 60 ° C., and the temperature of the heat storage material at the time of heat storage completion cannot be made higher than 60 ° C. . On the other hand, as is clear from FIGS. 3B and 3C, according to the present embodiment, the temperature of the heat storage material is raised to a temperature (80 ° C.) higher than the conventional temperature while suppressing the decrease in COP. be able to. Therefore, the heat storage amount can be increased as compared with the conventional case.

  In the present embodiment, the water stored in the water reservoir 16 is not heated in the first heat storage step. This is because, at the initial stage of heat storage, the temperature Tm of the heat medium is not high, so even if heat exchange is performed between the stored water and the heat medium, the water cannot be heated sufficiently. On the other hand, since the second heat storage step is performed after the temperature Tm of the heat medium becomes sufficiently high, the stored water can be quickly heated by the heat medium, and the decrease in COP is suppressed by cooling the heat medium. it can.

  In the present embodiment, the valve 24 is closed when the temperature Tm of the heat medium reaches 60 ° C., but the temperature Tm when the valve 24 is closed is not limited to 60 ° C., for example, 30 ° C. or more and 65 ° C. It may be the following. The temperature of the heat storage material 3 is high in the vicinity of the heat medium inlet in the heat storage material container 2, but is approximately the same as the temperature Tm of the heat medium in the vicinity of the heat medium outlet. For this reason, if temperature Tm is less than 30 degreeC, the temperature of the thermal storage material 3 located in the heat-medium exit vicinity will also be less than 30 degreeC, and there exists a possibility that a dehydration reaction may not fully advance. Moreover, since the stored water condensed by the condenser is about 9 ° C., the stored water can be heated by the heating medium if the temperature Tm of the heating medium is 30 ° C. or higher. More preferably, the temperature Tm is 40 ° C. or higher. This is because if the temperature of the heat storage material 3 is less than 40 ° C., the heat storage material 3 may not be sufficiently concentrated. As can be seen from FIG. 2, for example, when calcium chloride hydrate is used as the heat storage material, if the temperature of the heat storage material 3 is less than 40 ° C., the heat storage material 3 is concentrated until the salt concentration reaches about 60%. I can't. On the other hand, if the temperature Tm is 65 ° C. or less, the COP of the heat pump circuit 10 can be secured.

  If the valve 24 is closed when the temperature Tm of the heat medium is lower than 60 ° C., the temperature of the heat storage material 3 when the heat storage is completed becomes lower than the temperature (80 ° C.) shown in FIG. The increase in quantity is reduced. However, since the temperature Tm of the heat medium during the heat storage operation can be further lowered, the COP can be further increased.

<Heat dissipation operation>
Next, the operation | movement at the time of the thermal radiation operation of the thermal storage system of this embodiment is demonstrated.

  In this embodiment, after the said heat storage operation | movement, the water in the water reservoir 16 is supplied to the heat storage material container 2, and it thermally radiates by making it react with the heat storage material 3 of a heat storage state. Moreover, the heat | fever discharge | released in the thermal storage part 1 at the time of heat radiation is performed by making the 1st heat exchanger 4 heat-exchange the city water supplied from the water supply port 41, and the thermal storage material 3. FIG.

  First, the first operation pattern of the heat dissipation operation will be described. When heat storage is performed using the heat pump circuit 10, midnight power is often used. Late-night power is power that can be used only during a time period when power consumption is low from midnight to morning, and can be used at a regular one-third to one-fourth price by contract.

  In the first operation pattern, the heat storage is finished at the same time as the time zone of this midnight power is finished, and water is supplied from the water reservoir 16 to the heat storage unit 1. Specifically, when the midnight power period ends, the valves 26, 32, 33, 34, and 35 are opened, and the water stored in the water reservoir 16 is passed through the water supply path 45 by the pump 20. Send to sprinkler 40. When water is supplied to the heat storage material container 2 from the water sprinkling unit 40, the latent heat storage material 3 in a heat storage state (a state in which the hydration number has decreased) and water react. As a result, the heat storage material 3 returns to the heat dissipation state (hydration number before heat storage), and reaction heat is generated. Therefore, since the temperature of the latent heat storage material 3 becomes higher, more heat can be taken out.

  The water that reacts with the heat storage material 3 during heat dissipation is preferably heated by, for example, the second heat exchange unit 9. Although heat can be dissipated even if unheated water or city water is supplied, in that case, since the temperature of the water is low, the temperature of the heat storage unit 1 is lowered. This is because, at most, the amount of heat that can be recovered during heat dissipation is reduced.

  Next, a second operation pattern during heat dissipation will be described. If a long time elapses after the end of heat storage until a large load such as hot water is generated, heat loss from the heat storage unit 1 to the outside air becomes remarkable, causing hot water to run out. Therefore, if all the water in the water reservoir 16 is supplied to the heat storage unit 1 immediately after the end of the heat storage as in the first operation pattern, the heat dissipation loss until the time of heat use increases, and an efficient operation is achieved. There are cases where it is not possible.

  Therefore, in the second operation pattern, the amount of water supplied to the heat storage unit 1 is adjusted so that a large amount of heat can be taken out during a time period when a large load such as hot water supply is generated. For example, first, the valves 26, 32, 33, 34, and 35 are opened, and only a part of the water stored in the water reservoir 16 is supplied to the heat storage unit 1 immediately after the end of heat storage (first operation). When the first operation is finished, the valves 26, 32, 33, 34, and 35 are closed. Thereafter, the valves 26, 32, 33, 34, and 35 are opened again in accordance with a time zone in which a large load such as hot water supply is generated, and the water remaining in the water reservoir 16 is supplied to the heat storage unit 1. Thus, if water is supplied stepwise, an efficient operation with reduced heat dissipation can be performed.

  In the second operation pattern described above, in each of the first and second operations, the water supplied to the heat storage unit 1 is evenly distributed to the water spray unit 40 of the heat storage unit 1 and reacted with the heat storage material 3. Yes. However, depending on the physical properties of the latent heat storage material 3, if the amount of water to be reacted is small, the heat storage material 3 and water are difficult to mix uniformly, and there is a possibility that sufficient hydration reaction cannot be caused.

  Therefore, as a third operation pattern, the water supplied in stages from the water reservoir 16 can be sent to a part of the water sprinkling unit 40 that is predetermined for each stage. For example, in the first operation, the valves 26, 32 and 33 are opened, and water is supplied to the heat storage material 3 from the water sprinkling unit 40 connected to the valves 32 and 33. When the first operation is finished, the valves 26, 32 and 33 are closed. Thereafter, as a second operation, the valves 26, 34, 35 are opened and water is supplied from the sprinkler 40 connected to the valves 34, 35 in accordance with a time zone in which a large load such as hot water supply is generated. With such a configuration, it is possible to avoid a phenomenon in which the heat storage material 3 and the water are less likely to be mixed by reducing the amount of water to be reacted with the heat storage material 3.

  FIG. 5 is a graph for comparing the amount of heat extracted during heat dissipation in this embodiment with the amount of heat extracted in each of the heat storage methods disclosed in Patent Documents 3 and 4. As shown in FIG. 5, in the present embodiment, the amount of heat taken out can be increased by heating water (reserved water) that reacts with the heat storage material during heat dissipation. Further, as described above, since the heat storage material 3 can be heated to, for example, 80 ° C., the amount of heat (heat storage amount) that can be stored in the heat storage material 3 in the heat storage state increases, and the amount of heat extracted increases accordingly. As a result, the amount of heat that can be extracted and used by heat dissipation can be significantly increased as compared with the conventional case.

  Note that, as described above, Patent Document 4 proposes heating water collected from the heat storage material container during heat dissipation for the purpose of suppressing a decrease in the amount of heat extracted. On the other hand, in this embodiment, heating of stored water is performed at the time of heat storage. Accordingly, the stored water can be heated by heat exchange between the heat medium and the stored water, so that not only the amount of heat extracted during heat radiation can be increased, but also the temperature Tm of the heat medium can be kept low. Therefore, it is possible to suppress a decrease in COP of the heat pump circuit 10 due to an increase in the temperature Tm of the heat medium. In this way, not only can heat be efficiently extracted, but also the decrease in COP can be suppressed, so that the efficiency of the heat storage system can be greatly improved.

  The configuration of the heat storage system of the present embodiment is not limited to the configuration shown in FIG. In the present embodiment, the heat pump circuit 10 is used as the heat storage material heating unit, but other heat sources may be used. As another heat source, it is preferable to use a heat source whose operating temperature is fixed, and for example, waste heat of a fuel cell may be used. In the stored water heating unit 44, the stored water is heated by exchanging heat between the stored water and the heat medium. However, the stored water may be heated using another heat source. For example, the stored water may be heated by exchanging heat with the refrigerant of the heat pump circuit 10, or waste heat from other systems may be used.

  Furthermore, the configuration of the heat storage material container 3 is not limited to the laminated structure. Moreover, the utilization means of the heat | fever collect | recovered at the time of heat radiation is not limited to hot water supply, For example, you may utilize for a heating apparatus etc.

(Embodiment 2)
Hereinafter, a second embodiment of the heat storage system according to the present invention will be described with reference to the drawings. In this embodiment, the water collection | recovery part 11 has a some water reservoir, and the heat storage system of Embodiment 1 shown in FIG. 1 at the point which collect | recovers the water isolate | separated from the heat storage material 3 in order to a some water reservoir. Is different.

  FIG. 6 is a configuration diagram of the heat storage system of the present embodiment. For simplicity, the same components as those in the heat storage system shown in FIG.

<Configuration of heat storage system>
In the heat storage system of the present embodiment, the water recovery unit 11 includes a first water reservoir 16 and a second water reservoir 17 for recovering water discharged from the heat storage material container 2. The second evaporator (water condensing unit) 46 in the heat pump circuit 10 includes a first condenser 14 for condensing water transported from the heat storage material container 2 to the first water reservoir 16, and a second water reservoir. And a second condenser 15 for condensing the water transported to the vessel 16. A valve 24 is provided between the heat storage material container 2 and the first water reservoir 16, and a valve 25 is provided between the heat storage material container 2 and the second water reservoir 17. The movement of water between the material container 2 and each water reservoir can be controlled.

  The second heat exchanging unit 9 of the stored water heating unit 44 is configured to exchange heat between the water stored in the first or second water reservoirs 16 and 17 and the heat medium in the heat medium path 42. The water supply path 45 is configured to supply water in the first or second water reservoir 16, 17 to the heat storage unit 1 during heat radiation.

  Other configurations are the same as those of the heat storage system shown in FIG.

<Heat storage operation>
Next, the operation | movement at the time of the thermal storage driving | operation of the thermal storage system of this embodiment is demonstrated, referring drawings. FIG. 7 is a graph illustrating the relationship between the temperature of the heat storage material and the salt concentration during the heat storage operation.

  In this embodiment, from the state where all the valves 22 to 35 are closed, the first operation operation → the second operation operation → the third operation operation → the fourth operation operation is performed to store heat in the heat storage material 3. . Table 1 shows the open / close state of the valve in each operation. Table 2 shows an outline of each operation.

  In the first operation, the valve 23, the valve 24, and the valve 25 are first opened, and the pressure of the heat storage unit 1, the first condenser 14, and the second condenser 15 is lowered by the vacuum pump 21.

  When the pressures in the heat storage unit 1, the first condenser 14, and the second condenser 15 are reduced to predetermined values, the second operation is performed. In the second operation, the valve 23 and the valve 25 are closed while the valve 24 is open. Next, the heat storage unit 1 is heated by the heat pump circuit 10. At this time, the latent heat storage material 3, which is a hydrate, undergoes a phase change from a solid to a liquid, and subsequently the hydration number begins to decrease due to concentration. The water dehydrated from the latent heat storage material 3 becomes water vapor and is cooled by the first condenser 14 through the water vapor pipe 13. In addition, if the 1st condenser 14 which condenses the water vapor | steam of the water discharge path 43 is provided between the suction side of the compressor 6 and the 1st evaporator 7 as shown in Embodiment 1, COP of a heat pump cycle will be improved. be able to. And the condensed water produced | generated by the 1st condenser 14 is sent to the 1st water reservoir 16 via the valve 24, and is stored there.

  After the second operation is performed for a predetermined time, the valve 24 is closed and the valve 25 is opened. In this state, a third driving operation is performed. The timing for switching the valves 24 and 25 can be determined by detecting the water level of the water stored in the first recovery unit 16 or the pressure and temperature in the heat storage material container 2 with a sensor or the like.

  Specifically, the salt concentration of the heat storage material 3 is calculated using the water level stored in the first recovery unit 16 or the detection values of the pressure sensor and the temperature sensor in the heat storage material container 2. When the calculated salt concentration reaches a predetermined value, the valves 24 and 25 may be switched. When using the detected values of the pressure sensor and the temperature sensor in the heat storage material container 2, as illustrated in FIG. 8, the relationship between the pressure-temperature in the heat storage material container 2 and the salt concentration of the heat storage material is obtained in advance. Based on the relationship, the salt concentration can be calculated from the detected value. In the present embodiment, the valves 24 and 25 are switched when the calculated salt concentration reaches, for example, 55% (an intermediate point between the salt concentration at the start of heat storage and the salt concentration at the end of heat storage).

  In the third operation operation, the heat storage material 3 is heated, and water desorbed from the heat storage material 3 is taken out from the heat storage material container 2, condensed in the second condenser 15, and then stored in the second water reservoir 17. . At the same time, in the second heat exchange unit 9, heat exchange between the heat medium and the water stored in the first water reservoir 16 is performed. Specifically, the valve 30 attached to the first water reservoir 16 is opened, and the pressure of the first water reservoir 16 is increased to atmospheric pressure. Subsequently, the valve 26 and the valve 28 are opened, and the water stored in the first water reservoir 16 by the pump 19 is sent to the second heat exchange unit 9. By this operation, heat exchange between the heat medium after circulating the heat storage unit 1 and the water in the first water reservoir 16 is performed. Thereby, since temperature Tm of a heat carrier can be lowered | hung, the fall of COP of a heat pump cycle can be suppressed. Moreover, since the water stored in the 1st water reservoir 16 can be heated, it becomes possible to make hot water and the thermal storage material 3 react by the time of heat dissipation. Furthermore, since this operation is performed with the valve 24 closed, it is possible to prevent water from flowing backward from the water reservoir 16 to the heat storage material container 2.

  In the third operation, the water level of the second water reservoir 17, the temperature Tm of the heat medium after flowing through the heat storage unit 1 or the temperature of the condensed water in the first water reservoir 16 is detected by a sensor or the like. If the value is reached, the fourth driving operation is performed.

  In the fourth operation, the valves 25, 26, 28, and 30 are closed, and the valve 31 attached to the second water reservoir 17 is opened to raise the pressure of the second water reservoir 17 to atmospheric pressure. Thereafter, the valves 27 and 29 are opened, and the water stored in the second water reservoir 17 by the pump 19 is sent to the second heat exchanger 9. With this operation, heat exchange between the heat medium after flowing through the heat storage unit 1 and the water stored in the second water reservoir 17 is performed. Therefore, since the temperature of the heat medium can be lowered, the COP reduction can be suppressed. Moreover, the water stored in the second water reservoir 17 can be heated. Simultaneously with this operation, the heat storage material 3 is further heated by the heat pump circuit 10. However, in the fourth operation operation, since the valves 24 and 25 are both closed, water is not taken out from the heat storage material container 2.

  Also in the fourth operation, the temperature Tm of the heat medium after flowing through the heat storage unit 1 or the temperature of the water in the second water reservoir 17 is detected by a sensor or the like, and the heat storage is terminated when a predetermined value is reached. To do. When heat storage is complete, all valves are closed.

  In the present embodiment, as shown in the curve (A) in FIG. 7, the heat storage material 3 is heated to, for example, 60 ° C. and the salt concentration is concentrated to, for example, 60% by the second and third driving operations. . Similar to the first embodiment, the heat storage material 3 stores sensible heat, latent heat, and reaction heat. Subsequently, as shown in a straight line (B) in FIG. 7, the temperature of the heat storage material 3 rises to, for example, 70 ° C. by the fourth operation operation while maintaining the salt concentration of the heat storage material 3. Therefore, as in the first embodiment, the amount of heat storage can be increased as compared with the conventional case.

  Here, changes in the salt concentration of the heat storage material 3, the temperature of the heat storage material 3, and the temperature Tm of the heat medium in each heat storage process will be described in more detail with reference to the drawings.

  FIGS. 9A to 9C are graphs illustrating the relationship between the elapsed time from the start of the heat storage operation, the salt concentration of the heat storage material 3, the temperature Tm of the heat medium, and the temperature of the heat storage material 3, respectively. 9A to 9C, the second operation operation is from the start of heat storage to the time t ′, and the third operation operation is from the time t ′ to the time when the concentration of the heat storage material is completed (concentration completion time) t. From the concentration completion time t to the time (heat storage completion time) t2 at which the heating of the heat storage material is completed corresponds to the heat storage process by the fourth operation operation.

  As can be seen from FIG. 9B, during the second operation, the temperature Tm of the heat medium after heat exchange with the heat storage material 3 also increases as the temperature of the heat storage material 3 increases. At the time of the third driving operation, at the initial stage of the driving operation, the temperature Tm of the heat medium after flowing through the heat storage material 3 is cooled by the water in the water recovery unit 11 and rapidly decreases. As the temperature rises, the temperature of the heating medium also rises. Similarly, even during the fourth driving operation, the temperature Tm of the heat medium is low at the start of the driving operation, but then rises again. In this example, the heat storage is completed when the temperature Tm of the heat medium reaches 60 ° C.

  Thus, in this embodiment, since the temperature Tm of the heat medium can be suppressed to be lower than that of the conventional heat storage method (FIG. 4B), the COP is reduced due to the increase of the temperature Tm of the heat medium. Can be greatly suppressed. Moreover, since the temperature of the heat storage material 3 can be raised from 60 degreeC, heat storage amount can be made to increase rather than the conventional heat storage method (FIG.4 (c)).

  In addition, compared with the heat storage method (FIGS. 3B and 3C) of the first embodiment, in this embodiment, the temperature Tm of the heat medium can be suppressed lower than that of the first embodiment. COP can be improved. On the other hand, in the fourth operation, the amount of stored water that exchanges heat with the heat medium is smaller than that in the first embodiment (about 1/2), so the temperature Tm of the heat medium is shorter during the fourth operation. It will rise to 60 ° C over time. For this reason, the temperature of the heat storage material 3 at the time of heat storage completion becomes lower than the temperature of the heat storage material 3 of Embodiment 1, and the amount of heat storage becomes small.

  Therefore, which heat storage system of Embodiments 1 and 2 is more preferable depends on the application of the heat storage system. When it is desired to further increase the amount of heat storage, it is advantageous to use the heat storage system according to the first embodiment shown in FIG. 1, and to further improve the COP, it is advantageous to use the heat storage system according to the present embodiment shown in FIG. . In addition, the heat storage system shown in FIG. 6 is used, and when the valve is opened and closed, if necessary, the heat storage operation of the first embodiment is performed using only one water reservoir, and both water reservoirs are used. Thus, it is possible to selectively use the heat storage operation of the present embodiment.

  Note that, as in the present embodiment, when the water condensing unit (second evaporator) 46 and the water recovery unit 11 are each provided with a plurality of condensers and water reservoirs, one condenser is used during the heat storage operation. (24, 25) and the water reservoir (16, 17) while cooling the water vapor, using the water of the other water reservoir (17, 16) and the stored water heating unit 44, after heating the heat storage unit The temperature Tm of the heat medium can be lowered. Therefore, since COP can be reduced, a heat storage system excellent in thermal efficiency can be realized. Moreover, since it performs in the state which closed the valve provided between the other water storage device and the heat storage part 1, it can prevent that the water in a water storage device flows back into the heat storage part 1. FIG. Furthermore, since the temperature of the heat storage material 3 can be made higher than before by the fourth driving operation, the amount of heat storage can be increased.

  In addition, as a heat storage process, only the 1st-3rd driving | running operation is performed and it is not necessary to perform a 4th driving | running operation. Even in this case, the backflow of water can be prevented and the temperature increase of the heat medium can be suppressed during the second and third driving operations.

<Heat dissipation operation>
Next, the operation | movement at the time of the thermal radiation operation of the thermal storage system of this embodiment is demonstrated. Also in this embodiment, three types of operation patterns as described in the first embodiment can be performed. Further, the heat released from the heat storage material during heat radiation can be recovered by exchanging heat between the city water supplied from the water supply port 41 and the heat storage material 3 in the first heat exchanger 4.

  First, the open / close state of the valve in each operation pattern is shown in Table 3.

  First, the first operation pattern will be described. As in the first embodiment, in the first operation pattern, the heat storage is finished simultaneously with the end of the midnight power period, and the water stored in the water recovery unit 11 is supplied to the heat storage unit 1. Specifically, the valves 26, 27, 32, 33, 34, and 35 are opened, and the water stored in the first water reservoir 16 and the second water reservoir 17 is sent to the sprinkler 40 by the pump 20. When water is supplied from the water sprinkling unit 40 to the heat storage material container 2, the heat storage material 3 in a heat storage state with a reduced hydration number reacts with water, and the hydration number of the heat storage material 3 increases and hydration reaction occurs. Heat is generated. Therefore, since the latent heat storage material 3 has a higher temperature, a larger amount of heat can be extracted.

  Next, the second operation pattern will be described. Similarly to the first embodiment, the supply amount of water to be reacted with the heat storage material 3 is adjusted so that a large amount of heat can be taken out in a time zone in which a large load such as hot water supply is generated. For example, immediately after the end of heat storage, the valves 26, 32, 33, 34, and 35 are opened, and only the water stored in the first water reservoir 16 is supplied to the heat storage unit 1 (first operation). When the first operation is finished, the valves 26, 32, 33, 34, and 35 are closed. Next, the valves 27, 32, 33, 34, and 35 are opened in accordance with a time zone in which a large load such as hot water supply is generated, and the water stored in the second water reservoir 17 is supplied to the heat storage unit 1 (second Behavior). In this way, by utilizing the fact that a plurality of water reservoirs are provided, water is supplied stepwise, so that heat dissipation loss can be suppressed and the heat storage system can be operated efficiently.

  Next, the third operation pattern will be described. In a 3rd driving | running pattern, the watering part 40 which supplies water is predetermined for every water reservoir. Specifically, in the first operation, the valves 26, 32, and 33 are opened, and the water in the first water reservoir 16 is supplied to the heat storage material container 2 from the water sprinkling unit 40 connected to the valves 32 and 33. When the supply of water from the first water reservoir 16 is completed, the valves 26, 32, and 33 are closed. Subsequently, as a second operation, the valves 27, 34, and 35 are opened in accordance with a time zone in which a large load such as hot water supply is generated, and the sprinkler 40 connected to the valves 34 and 35 is transferred to the heat storage material container 2. The water of the second water reservoir 17 is supplied. Thereby, the phenomenon which becomes difficult to mix the thermal storage material 3 and water by the amount of the water made to react can be avoided similarly to Embodiment 1. FIG.

(Embodiment 3)
Hereinafter, the third embodiment of the heat storage system of the present invention will be described with reference to the drawings. In the present embodiment, in order to heat the water stored in the water recovery unit 11, the heat storage system of the second embodiment shown in FIG. Is different.

  FIG. 10 is a configuration diagram of the heat storage system of the present embodiment. For simplicity, the same components as those in the heat storage system shown in FIG.

  In the heat storage system of the present embodiment, a fourth heat exchanger 48 for heating the stored water is provided between the expansion valve 8 of the heat pump circuit 10 and the third heat exchanger (heat medium heating unit) 39. Yes. In addition, the stored water heating unit 47 has a path for circulating the stored water between the fourth heat exchanger 48 and the water reservoirs 16 and 17. Thus, it replaces with the 2nd heat exchange part 9 (FIG. 6) and the stored water heating part 44 (FIG. 6), and is the point except having the 4th heat exchange part 48 and the stored water heating part 47 in FIG. It can have the same configuration as the heat storage system shown in FIG.

  In the present embodiment, the fourth heat exchanging unit 48 performs heat exchange between the refrigerant that has passed through the third heat exchanging unit 39 and the water stored in the water recovery unit 11. Thereby, since the temperature of the refrigerant before flowing into the expansion valve 8 can be lowered, the COP reduction of the heat pump circuit 10 can be suppressed. In addition, since the water stored in the water recovery unit 11 can be heated by heat exchange with the refrigerant, the hot water and the heat storage material 3 can be reacted with each other at the time of heat radiation, and the water is efficiently stored. Heat can be recovered. Therefore, the same effect as that of the above-described embodiment can be obtained. Furthermore, according to this structure, even when heating the water of the water collection | recovery part 11 after completion | finish of a heat storage driving | operation, it can heat directly with the heat pump circuit 10. FIG.

  The heat storage system according to the present invention can be used for hot water heaters, air conditioning equipment, industrial waste heat storage, and the like, and can be particularly suitably used for water heaters.

DESCRIPTION OF SYMBOLS 1 Heat storage part 2 Heat storage material container 3 Latent heat storage material 4 1st heat exchange part 5 Fin 6 Compressor 7 1st evaporator 8 Expansion valve 9 2nd heat exchange part (Reserved water heating part, stored water / heat-medium heat exchange part )
DESCRIPTION OF SYMBOLS 10 Heat pump 11 Water recovery part 12 Hot-water supply port 13 Water vapor pipe 14 1st condenser 15 2nd condenser 16 1st water reservoir 17 2nd water reservoir 18, 19, 20 Pump 21 Vacuum pump 22-35 Valve 36, 37 , 38 Three-way valve 39 Third heat exchange part (heat medium heating part)
40 Water sprinkling part 41 Water supply port 42 Heat transfer medium circuit 43 Water discharge path 44 Reserving water heating circuit 45 Water supply path 46 Second evaporator (water condensing part)
47 Reservoir Heating Circuit 48 Fourth Heat Exchanger

Claims (11)

A heat storage method using a heat storage material that stores heat by desorbing water and releases heat by reacting with water,
(A) a first heat storage step of heating the heat storage material accommodated in the heat storage material container, taking out water desorbed from the heat storage material from the heat storage material container and storing the water in a water reservoir;
(B) blocking the movement of the desorbed water between the heat storage material container and the water reservoir;
(C) in the shut-off state, further heating the heat storage material to further increase the temperature of the heat storage material, and heating the desorbed water stored in the water reservoir; ,
(D) A heat storage method including a heat release step of supplying the heated water to the heat storage material container and reacting the desorbed water with the heat storage material. The step (a) includes a compressor, a radiator, an expansion device, an evaporator, and a heat medium heated by the radiator of a heat pump circuit including a refrigerant path that circulates the refrigerant therebetween, and the heat storage material. Heating the heat storage material by heat exchange,
The step (c) heats the desorbed water by exchanging heat between the desorbed water stored in the water reservoir and the heating medium before being heated by the radiator. The heat storage method of Claim 1 including the process to do. The step (a) includes a step of measuring the temperature of the heat medium after being heat-exchanged with the heat storage material and before being heated by the radiator.
The heat storage method according to claim 2, wherein the step (b) is a step of blocking the movement of the desorbed water when the measured heat medium temperature becomes equal to or higher than a predetermined temperature.   The heat storage method according to any one of claims 1 to 3, wherein in the step (c), the heat storage material is heated without taking out the detached water from the heat storage material container.   5. The process according to claim 1, wherein the step (c) includes a step of heating the heat storage material and taking out water desorbed from the heat storage material from the heat storage material container and storing the water in another water reservoir. The heat storage method described in 1. A heat storage system that stores heat by desorbing water from the heat storage material, and dissipates heat by reacting the desorbed water with the heat storage material,
A heat storage material container for storing the heat storage material;
During the heat storage operation, a heat storage material heating unit for heating the heat storage material,
A water reservoir for storing water desorbed from the heat storage material by heating the heat storage material;
A water transport path for moving the desorbed water from the heat storage material container to the water reservoir;
A condensing part that is provided in the water transport path and condenses the desorbed water;
A valve provided in the water transport path for limiting movement of the detached water between the heat storage material container and the water reservoir;
A stored water heating unit for heating the desorbed water stored in the water reservoir;
A water supply path for supplying the desorbed water from the water reservoir to the heat storage material container during heat radiation operation;
The valve is switched from the open state to the closed state during the heat storage operation,
In the heat storage operation, the stored water heating unit heats the detached water when the valve is in a closed state. The heat storage material heating unit is
A heat pump circuit including a compressor, a radiator, an expansion device, an evaporator, and a refrigerant path for circulating the refrigerant between them;
A heating medium path for circulating the heating medium to be heated by the radiator and cooled by exchanging heat with the heat storage material;
The condensing unit is configured to cool the desorbed water by exchanging heat with the refrigerant of the heat pump circuit,
The stored water heating unit exchanges heat between the desorbed water stored in the water reservoir and the heat medium after heat exchange with the heat storage material and before being heated by the radiator. The heat storage system of Claim 6 containing the stored water / heat-medium heat exchange part to be made. A temperature measuring unit that is provided in the heat medium path and that measures the temperature of the heat medium after heat exchange with the heat storage material and before being heated by the radiator;
The heat storage system according to claim 7, wherein in the heat storage operation, the valve is switched from an open state to a closed state when a temperature measured by the temperature measurement unit is equal to or higher than a predetermined temperature.   The heat storage system according to any one of claims 6 to 8, wherein, in the heat storage operation, when the valve is in a closed state, the heat storage material is heated without taking out the detached water from the heat storage material container. Another water reservoir for storing the desorbed water;
Another water transport path for moving the desorbed water from the heat storage material container to the other water reservoir;
Provided in the other water transport path, further comprising another valve for restricting the movement of the detached water between the heat storage material container and the other water reservoir,
The heat storage system according to any one of claims 6 to 8, wherein, in the heat storage operation, the other valve is switched to be in a closed state when the valve is in an open state and to be in an open state when the valve is in a closed state. .   The heat storage system according to claim 10, further comprising another stored water heating unit that heats the detached water stored in the other water reservoir.

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