JP2016217664A - Heat storage system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To remove a radiating thermal media with its temperature kept high for a long period of time.SOLUTION: Heat storage tanks 1a, 1b, 1c comprise heating means 3a, 3b and 3c at a bottom part in a storage tank space 8 having heat storage material 2 stored therein, and radiating heat transfer pipes 4a, 4b, 4c in an upper part of the storage tank space. The radiating heat transfer pipes 4a, 4b, 4c in the heat storage tanks 1a, 1b, 1c are connected in series through which a radiating thermal media 5 flows. To carry out heat storage in the heat storage tanks 1a, 1b, 1c, heating means 3a, 3b, 3c are controlled by a control device 7 to carry out a heat storing operation from the last heat storage tank 1c in a flowing order of the radiating thermal media, to reach a specified high heat storage state. To carry out heat radiation from the heat storage tanks 1a, 1b, 1c, the pre-heated or pre-heat stored radiating thermal media 5 in the first two heat storage tanks 1a, 1b in the flowing order of the radiating thermal media is flowed to the radiating heat transfer pipe 4c of the heat storage tank 1c, to hold the heat storage tank 1c that is the last to exchange heat with the radiating thermal media 5, at a high heat storage state for a long period of time.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a heat storage system used for heat storage.

  In power generation facilities that use natural energy such as solar thermal power generation, solar power generation, and wind power generation, a heat storage system should be provided to suppress transient changes in output power caused by changes in sunshine conditions and weather conditions. Has been done.

  As this type of heat storage system, for example, a heat storage tank is filled with a heat storage material that causes a phase change between a solid phase and a liquid phase in a heat storage temperature range, and heat storage is performed using the latent heat of this heat storage material, The thing which aimed at the improvement of a thermal storage density is conventionally known.

  Furthermore, there are cases where a plurality of heat storage tanks (heat storage units) are used in combination, and in that case, heat transfer tubes for heat radiation of each heat storage tank are arranged in series so as to exchange heat between the heat storage material and water in each heat storage tank. (See, for example, Patent Document 1).

Examples of the heat storage material that causes a phase change between the solid phase and the liquid phase in the heat storage temperature range include CsNO ₃ and NaNO ₃ , LiNO ₃ and LiOH, LiNO ₃ and NaNO ₃ , KNO ₃ and NaNO ₃ , NaNO ₃ and Conventionally, it has been proposed to use a heat storage material composed of a mixed salt having a non-eutectic composition of two components such as RbNO ₃ , LiBr and LiOH, and LiBr and NaNO ₃ (see, for example, Patent Document 2).

JP 2001-248984 A International Publication No. 2014/185179

  By the way, when using a plurality of heat storage tanks by connecting heat transfer tubes for heat dissipation in series, the heat storage tank having the first heat medium distribution order when the heat transfer heat medium is sequentially distributed to the heat transfer tubes of each heat storage tank is The heat radiating heat medium having an initial temperature supplied from the heat medium supplying means or the like flows through the heat radiating heat transfer tubes. On the other hand, in the heat storage tanks in which the heat medium distribution order is the second or later, the heat dissipation heat medium after the heat medium distribution order has passed through the heat dissipation heat transfer pipes of the previous heat storage tank flows through the heat dissipation heat transfer pipes. become. For this reason, when radiating heat from each heat storage tank via the heat dissipation heat medium, the temperature difference of the heat dissipation heat medium flowing through the heat transfer tubes differs for each heat storage tank. There is a difference. Therefore, variation occurs in the amount of heat stored in each heat storage tank.

  Moreover, when a plurality of heat storage tanks that have been proposed in the past are connected in series, the heat storage amount to each heat storage tank and the heat release from each heat storage tank from the state in which the amount of heat stored in each heat storage tank varies. Is simply repeated, there is a concern that all the heat storage tanks have a heat storage amount between the upper limit and the lower limit of the set heat storage capacity.

  Moreover, the temperature of the heat-dissipating heat medium that can be taken out of the heat storage tank decreases as the heat storage amount decreases from the upper limit of the heat storage capacity. Therefore, even if the total value of the heat storage amount of the plurality of heat storage tanks reaches the upper limit of the heat storage capacity of one heat storage tank, in the state where the temperature of each heat storage tank is lowered, the heat radiation finally taken out The temperature of the heat transfer medium is greatly reduced as compared to the heat dissipation heat medium taken out from the heat storage tank whose heat storage capacity is the upper limit heat storage amount.

  In addition, patent document 2 does not show the idea of integrating and operating a plurality of heat storage tanks.

  Therefore, the present invention intends to provide a heat storage system capable of increasing the temperature of the heat-dissipating heat medium finally exchanged with heat storage materials of a plurality of heat storage tanks over a long period of time. It is.

  In order to solve the above problems, the present invention performs heat exchange with the heat storage material by circulating a heat storage material placed in a tank and a heat-dissipating heat medium having a temperature lower than that of the heat storage material in the tank. A plurality of heat storage tanks, each of which is provided in the heat storage tube and a heating unit that heats the heat storage material for heat storage, and the plurality of heat storage tanks include the heat transfer tubes The heat dissipating heat medium is connected in series so that it flows in order, and further includes a control device that controls the heating means of the plurality of heat storage tanks, and the control device includes the heat dissipating heat transfer tubes connected in series. In addition, when performing heat storage on the plurality of heat storage tanks, from the heat storage tank in which the heat dissipation heat medium circulation sequence is the last when the heat dissipation heat medium flows through the heat dissipation heat transfer tubes connected in series, The heat storage tanks are arranged in the reverse order to the heat dissipation heat medium distribution order. The heat storage of up to a high heat storage state is set to the thermal storage system having the configuration as having the function of performing separately.

  The heat storage material causes a solid-liquid phase change in the heat storage temperature range of the heat storage tank, and each of the heat storage tanks includes the heating means on the bottom side of the space in the tank containing the heat storage material, and It is set as the structure provided with the said heat exchanger tube for heat radiation near the upper part of the space in a tank.

  The heating means of each heat storage tank includes a heat medium flow path for circulating a heat medium for heating, the heat medium flow path is connected to a heating heat medium supply line via an on-off valve, and the control device The open / close valve for each heat medium flow path of each heat storage tank has a function of opening / closing individually.

  The heating means of each heat storage tank includes an electric heater, and the control device has a function of individually operating power supply and power supply stop for each electric heater of each heat storage tank.

  According to the heat storage system of the present invention, it is possible to increase the temperature of the heat-dissipating heat medium finally taken out by exchanging heat with the heat storage materials of the plurality of heat storage tanks over a long period of time.

It is a general | schematic cutting side view which shows 1st Embodiment of a thermal storage system. It is a flowchart of the heat storage heat processing by the control apparatus in 1st Embodiment. (A) (b) (c) is a figure which shows the state at the time of the thermal storage by the thermal storage system of 1st Embodiment. (A) (b) (c) is a figure which shows the state at the time of the thermal radiation by the thermal storage system of 1st Embodiment. It is a general | schematic cutting side view which shows 2nd Embodiment of a thermal storage system.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

[First Embodiment]
FIG. 1 is a schematic cut side view showing a first embodiment of a heat storage system. FIG. 2 is a flow chart of heat storage heat treatment by the control device in the present embodiment. FIGS. 3A, 3B, and 3C are views showing a state during heat storage of the heat storage system of the present embodiment. FIGS. 4A, 4B, and 4C are views showing a state during heat dissipation of the heat storage system of the present embodiment.

  In summary, the heat storage system of the present embodiment includes a plurality of heat storage tanks 1a, 1b, and 1c as shown in FIG. FIG. 1 shows a configuration example in which three heat storage tanks 1a, 1b, and 1c are used.

  The heat storage tanks 1a, 1b, 1c are the heat storage material 2 put in the tank, the heating means 3a, 3b, 3c for heating the heat storage material 2 in the tank, and the heat transfer tubes 4a, 4b for heat radiation. , 4c.

  The heat transfer tubes 4a, 4b, 4c for heat dissipation distribute the heat dissipation heat medium 5 having a temperature lower than that of the heat storage material 2 in the tank, and exchange heat between the heat dissipation heat medium 5 and the heat storage material 2 in the tank. This is a heat transfer tube for obtaining the heat radiating heat medium 5 heated by this heat exchange.

  Each of the heat storage tanks 1a, 1b, and 1c is connected to the heat radiating heat transfer tubes 4a, 4b, and 4c in series, and the heat radiating heat medium 5 supplied from an external heat radiating heat medium supplying means (not shown) The heat radiating heat transfer tubes 4a, 4b, 4c of the tanks 1a, 1b, 1c are circulated in order. The order in which the heat dissipation heat medium 5 flows through the heat transfer tubes 4a, 4b, and 4c of the heat storage tanks 1a, 1b, and 1c in this manner is as follows. It is called order.

  The heat storage system of the present embodiment further includes heat storage amount measuring means 6a, 6b, 6c for measuring the heat storage amount of each heat storage tank 1a, 1b, 1c, and heating means 3a, 3b for each heat storage tank 1a, 1b, 1c, The controller 7 is configured to be integrated and controlled.

In the heat storage system of this embodiment, the heat storage material 2 put in the tanks of the heat storage tanks 1a, 1b, 1c is, for example, a solid phase and a liquid phase in a set heat storage temperature range ( _Tmin <T < _Tmax ). A heat storage material 2 is used in which a phase change occurs between them and the density of the solid phase is larger than the density of the liquid phase. In FIG. 1, the solid phase of the heat storage material 2 is hatched. The details of the heat storage material 2 will be described later.

  The volume of the in-tank space 8 of the heat storage tanks 1a, 1b, 1c is appropriately set according to the heat storage capacity desired for the heat storage tanks 1a, 1b, 1c, the type of the heat storage material 2, and the like.

  The heating means 3a, 3b, 3c are provided in a hot plate shape at the bottom of the in-tank space 8. The heating means 3a, 3b, 3c are provided, for example, on a plate member 9 for forming the inner bottom surface of the tank space 8 as a flat surface, and on the lower side of the plate member 9, and the heating medium 11 is circulated. The heat medium flow path 10 is provided.

  The plate member 9 is configured to disperse and deposit the solid phase of the heat storage material 2 that is generated and settles in the internal space 8 when the temperature of the heat storage tanks 1a, 1b, 1c is lowered, and deposited on the upper side of the plate member 9, This is because it is preferable to receive the load of the deposit in a distributed manner on the surface of the plate member 9. The heating means 3a, 3b, 3c are configured to apply a load of deposits acting on the plate member 9 to the lower side of the heat medium flow path 10 which is the lower end of the heating means 3a, 3b, 3c. You may make it provide the upper and lower columnar and wall-shaped members for conveying and supporting.

  The heat medium channel 10 is arranged and shaped in the flow path of the heating medium 11 in the plane of the plate member 9 so that the entire surface of the plate member 9 can be heated as evenly as possible by the heat of the heating medium 11. The channel cross-sectional area and the like are set as appropriate. In FIG. 1, for convenience of illustration, the heat medium passage 10 is simplified. Therefore, it is needless to say that the heat medium flow path 10 may have any setting other than that shown in the drawing, such as the arrangement, shape, and cross-sectional area of the flow path.

  At the inlet of the heat medium flow path 10 of each heat storage tank 1a, 1b, 1c, a heating heat medium supply line 12 for guiding the heating heat medium 11 from an external heating medium supply means (not shown) is provided as an individual on-off valve. They are connected in parallel via 13a, 13b and 13c.

  Further, on the downstream side of the outlet of the heat medium flow path 10 of each heat storage tank 1a, 1b, 1c, the heating heat medium 11 after flowing through the heat medium flow path 10 is returned to the heating heat medium supply means. A heating medium return line 14 is connected. Further, the heating heat medium supply means is provided with a heat exchanging section for applying heat from a heat source (not shown) such as a heat collecting section of solar thermal power generation to the heating heat medium 11 for heating.

As the heating heat medium 11, a heat medium that is in a liquid phase up to the entire heat storage temperature range (T _min <T <T _max ) or higher than that is selected and used, or steam is used. What should I do? Since the temperature of the steam can be easily adjusted by adjusting the pressure, the temperature of the heating means 3a, 3b, 3c can be easily adjusted by using the steam as the heating heat medium 11.

  Thereby, the heated heating medium 11 can be circulated and supplied from the heating medium supply means to the heating medium flow path 10 of the heating means 3a, 3b, 3c. Therefore, in the heating means 3 a, 3 b, 3 c, the heat storage material 2 put in the tank internal space 8 is moved downward via the plate member 9 by the heat of the heating heat medium 11 sequentially supplied to the heat medium flow path 10. Can be heated.

  The heat radiating heat transfer tubes 4 a, 4 b, 4 c are provided at positions near the upper part of the tank space 8 so as to be immersed in the heat storage material 2. The heat radiating heat transfer tubes 4a, 4b, and 4c are supported from the wall surfaces and ceiling portions of the heat storage tanks 1a, 1b, and 1c via a support member (not shown). It is preferable that the heat radiating heat transfer tubes 4a, 4b, 4c are arranged as far as possible above the half height position in the vertical direction of the in-tank space 8 as long as the whole is immersed in the heat storage material 2. This is for preventing the phenomenon that the solid phase of the heat storage material 2 solidified around the heat transfer tubes 4a, 4b, 4c for heat dissipation settles in the liquid phase, as will be described later. However, the part located on the lower end side of the heat transfer tubes 4a, 4b, 4c for heat dissipation is in the vertical direction of the inner space 8 depending on the pipe shape and the overall size of the heat transfer tubes 4a, 4b, 4c for heat dissipation. Of course, it may be partially disposed at a half height position or a lower position.

  The heat transfer tubes 4a, 4b, 4c of the heat storage tanks 1a, 1b, 1c are sequentially connected in series via a connection member 15 such as a connector or a connection tube. In FIG. 1, the downstream end of the heat radiating heat transfer tube 4a and the upstream end of the heat radiating heat transfer tube 4b are connected, the downstream end of the heat radiating heat transfer tube 4b, and the upstream of the heat radiating heat transfer tube 4c. The side end portion is connected.

  Of each heat-dissipating heat transfer tube 4a, 4b, 4c, the heat-dissipating heat medium 5 is provided at the upstream end of the heat-dissipating heat transfer tube 4a arranged on the most upstream side by an external heat-dissipating heat medium supplying means (not shown). A heat dissipation heat medium supply line 16 is connected. Further, at the downstream end of the heat radiating heat transfer tube 4c arranged on the most downstream side, the heat radiating heat medium 5 after flowing through the heat radiating heat transfer tubes 4a, 4b, 4c of the heat storage tanks 1a, 1b, 1c. To the desired heat load (not shown) is connected. The heat dissipation heat medium 5 after supplying heat to the heat load may or may not be returned to the heat dissipation heat medium supply means.

  As the heat dissipation heat medium 5, a liquid heat medium may be selected and used, or steam may be used. Alternatively, a liquid-phase heat medium may be used as the heat-dissipating heat medium 5, and the liquid-phase heat-dissipating heat medium 5 may be evaporated in the heat-radiating heat transfer tubes 4a, 4b, 4c.

  Thereby, the heat-dissipating heat medium 5 is continuously supplied from the heat-dissipating heat medium supplying means to the heat-dissipating heat transfer tubes 4a, 4b, 4c. Therefore, the heat-dissipating heat medium 5 flowing through the heat-dissipating heat transfer tubes 4a, 4b, 4c is sequentially heated by heat exchange with the heat storage material 2 existing around the heat-dissipating heat transfer tubes 4a, 4b, 4c. In this state, the heat retained by the heat dissipation heat medium 5 collected in the heat dissipation heat medium delivery line 17 is applied to the heat load.

  Thus, the heat-dissipating heat medium 5 flowing through the heat-radiating heat transfer tubes 4a, 4b, 4c is heated by heat exchange with the heat storage material 2 existing around the heat-radiating heat-transfer tubes 4a, 4b, 4c. Sometimes, the heat storage material 2 relatively decreases in temperature. When the temperature drop of the heat storage material 2 occurs at the phase change temperature between the liquid phase and the solid phase, as shown in FIG. 1, the heat storage material 2 is moved from the liquid phase around the heat transfer tubes 4 a, 4 b, 4 c for heat radiation. Solidifies to form a solid phase. Since the solid phase of the heat storage material 2 has a higher density than the liquid phase, it settles in the liquid phase.

  In the internal space 8, the heat transfer tubes 4 a, 4 b, 4 c are provided at positions closer to the upper portion thereof, so that the solid phase of the heat storage material 2 whose temperature has dropped around the heat transfer tubes 4 a, 4 b, 4 c is provided. Even if it occurs, this solid phase settles down in the tank space 8 to the bottom and is deposited on the upper side of the heating means 3a, 3b, 3c.

  Therefore, in the heat storage tanks 1a, 1b, and 1c, the solid phase of the heat storage material 2 does not stay around the heat dissipation heat transfer tubes 4a, 4b, and 4c, and therefore the heat storage material 2 and the heat dissipation heat transfer tubes 4a, 4b, and 4c. It is suppressed that the efficiency of heat transfer between the heat-dissipating heat medium 5 flowing through the heat storage material 2 decreases due to the presence of the solid phase of the heat storage material 2.

  As shown in FIG. 1, side wall heaters 19 for increasing the temperature of the side walls 18 are preferably provided on the side walls 18 of the heat storage tanks 1a, 1b, 1c.

  It is preferable that the side wall heater 19 is provided so as to reach at least a half height in the vertical direction of the inner space 8 from the lower end side of the inner space 8. The side wall heater 19 is preferably provided over the entire circumference of the side wall 18. The side wall heater 19 may be provided along the inner surface of the side wall 18 (not shown) in addition to the configuration provided on the outer surface of the side wall 18 as shown in FIG. Further, although not shown, the side wall heater 19 may be provided over the entire range in the vertical direction in which the heat storage material 2 in the tank internal space 8 is stored.

  The side wall heater 19 may be an electric heater, for example. Or the heater 19 for side walls is good also as a heater of the structure provided with the heat medium flow path which distribute | circulates a steam and other liquid phase heat media like the heating means 3a, 3b, 3c.

  Further, the side wall heater 19 also heats the side wall 18 by the side wall heater 19 when the heat storage material 2 is heated by the heating means 3a, 3b, 3c, that is, when heat is stored in the heat storage tanks 1a, 1b, 1c. Is set to

  The heating temperature of the side wall 18 by the side wall heater 19 may be set to a temperature at which the heat storage material 2 changes from a solid phase to a liquid phase.

  Thereby, at the time of heating by the heating means 3a, 3b, 3c, the solid phase of the heat storage material 2 deposited on the upper side of the heating means 3a, 3b, 3c in the inner space 8 is heated from below, It melts from the portion in contact with the upper surface of the means 3a, 3b, 3c to become a liquid phase.

  At this time, by operating the side wall heater 19 together, the solid phase of the heat storage material 2 existing in the vicinity of the inner surface of the side wall 18 is melted into a liquid phase. For this reason, the solid phase deposit of the heat storage material 2 is eliminated from the inner surface of the side wall 18. Furthermore, the liquid phase of the heat storage material 2 generated at the portion in contact with the upper surface of the heating means 3a, 3b, 3c flows at a position along the inner periphery of the side wall 18 and moves above the solid deposit of the heat storage material 2. To do.

  As a result, in the tank space 8, the solid phase deposit of the heat storage material 2 can be pressed against the upper surface of the heating means 3a, 3b, 3c by its own weight, and at that time, the upper surface of the heating means 3a, 3b, 3c and The liquid phase layer of the heat storage material 2 formed between the deposits can be thinned. Thereby, the efficiency of heat transfer from the heating means 3a, 3b, 3c to the solid phase of the heat storage material 2 can be increased.

  Furthermore, even if volume expansion occurs with the phase change from the solid phase to the liquid phase in the heat storage material 2 existing in the portion in contact with the upper surface of the heating means 3a, 3b, 3c, The material 2 can be easily absorbed by moving the liquid phase upward of the solid phase. Therefore, when the heat storage material 2 is heated, the possibility that an excessively large pressure acts locally on the heat storage tanks 1a, 1b, 1c and the side wall 18 is prevented.

Furthermore, due to an unforeseen situation, the heat storage tanks 1a, 1b, 1c as a whole have a temperature lower than the heat storage temperature range ( _Tmin <T < _Tmax ), and the heat storage material 2 placed in the tank inner space 8 is When all of them are in a solid phase, the temperature of the heat storage tanks 1a, 1b, 1c is increased by melting the heat storage material 2 in a wide range in the vertical direction by operating the heater 19 for the side wall. It is possible to return to the range.

  Next, the heat storage material 2 will be described.

  The heat storage material 2 that solidifies around the heat transfer tubes 4a, 4b, 4c for heat dissipation when the heat stored in the heat storage material 2 is dissipated using the heat dissipation heat medium 5 flowing through the heat transfer tubes 4a, 4b, 4c. If the solid phase adheres to the surface of the heat transfer tubes 4a, 4b, 4c for heat radiation, the heat transfer efficiency is lowered due to the presence of the solid phase of the heat storage material 2.

As a research result of measures against such a decrease in heat transfer efficiency, as shown in Patent Document 2, it is difficult for the solid phase of the heat storage material 2 to adhere to the surfaces of the heat transfer tubes 4a, 4b, 4c for heat radiation. In order to do this, the heat storage material 2 is made of a binary mixed salt of a non-eutectic composition that is in a solid-liquid coexistence state at the minimum heat storage temperature T _min in the heat storage temperature range (T _min <T <T _max ). Has been found to be advantageous.

For example, when assuming application to a high-temperature system such as solar thermal power generation, the minimum heat storage temperature T _{min in} the heat storage temperature range (T _min <T <T _max ) desired for the heat storage system is 150 ° C. or higher, preferably 200 ℃ or more.

Therefore, as an example, the heat storage temperature range (T _min <T <T _max ) in the heat storage system of the present embodiment is an example in which the maximum heat storage temperature T _max is set to 400 ° C. and the minimum heat storage temperature T _min is set to 250 ° C. Is shown below.

As the heat storage material 2 suitable for this condition, for example, potassium nitrate (KNO ₃ ) and sodium nitrate (NaNO ₃ ) are used in combination of the two-component mixed salts shown in Patent Document 2 as non-covalent. There is a binary mixed salt mixed in a composition that forms crystals.

In this mixture of potassium nitrate and sodium nitrate, a eutectic is formed with a composition in which the molar fraction of sodium nitrate is 0.49. Therefore, a composition other than the composition that becomes the eutectic is used, and the heat storage minimum temperature T _min is 250. A solid-liquid coexistence state is established at ° C. As a specific composition example, an example in which a composition having a molar fraction of sodium nitrate of 0.786 (mass fraction of 0.755) is used as the heat storage material 2 will be described.

The heat storage material 2 is only in the liquid phase at 400 ° C., which is the maximum heat storage temperature T _max , and when it is gradually cooled from this state, a solid phase is generated at 274 ° C. When the heat storage material 2 is further cooled, the temperature decreases to 250 ° C., which is the minimum heat storage temperature T _min , while the ratio of the solid phase gradually increases. During this cooling, the heat storage material 2 generates a solid phase on the surface of the heat radiating heat transfer tubes 4a, 4b, 4c having the lowest temperature, and the solid phase grows along the surface of the heat radiating heat transfer tubes 4a, 4b, 4c. However, since the solid phase is difficult to adhere to the surfaces of the heat transfer tubes 4a, 4b, and 4c for heat radiation, the solid phase is peeled off by the flow of the heat storage material 2 or the like. In addition, if the heat storage material 2 is further cooled from 250 _degreeC which is the heat storage minimum temperature _Tmin , the whole heat storage material 2 will be in a solid phase at 234 degreeC.

Therefore, the heat storage tanks 1a, 1b, and 1c using the heat storage material 2 have a sensible heat of the heat storage material 2 and the heat storage material 2 from the solid phase in a temperature range from 250 ° C. to 274 ° C. of the minimum heat storage temperature T _min. Heat storage is performed by the latent heat when the liquid phase is melted, and heat storage is performed by sensible heat of the heat storage material 2 in a temperature range of 274 ° C. to 400 ° C. from the maximum heat storage temperature T _max .

In addition, as the heat storage material 2, when the maximum heat storage temperature T _max is set to 400 ° C. and the minimum heat storage temperature T _min is set to 250 ° C. as described above, the two-component mixing shown in Patent Document 2 Of the salt combinations, for example, a mixture of CsNO ₃ and NaNO _3, a mixture of LiNO ₃ and NaNO _{3, and} a mixture of NaNO ₃ and RbNO ₃ can be used.

When a mixture of CsNO ₃ and NaNO ₃ is used, the molar fraction of NaNO ₃ is 0.902 (mass fraction is 0.801), and when a mixture of LiNO ₃ and NaNO ₃ is used, the molar fraction of NaNO ₃ When the ratio is 0.877 (mass fraction is 0.898) and a mixture of NaNO ₃ and RbNO ₃ is used, the molar fraction of RbNO ₃ is 0.105 (mass fraction is 0.169). Thus, a solid-liquid coexistence state can be obtained at 250 ° C., which is the lowest heat storage temperature T _min .

Further, when the minimum heat storage temperature T _{min in} the heat storage temperature range (T _min <T <T _max ) is set to 280 ° C., the heat storage material 2 is a mixture of two components shown in Patent Document 2 above. Of the salt combinations, it is possible to use a mixture of LiBr and NaNO ₃ . In this case, by setting the molar fraction of NaNO ₃ to 0.964 (mass fraction of 0.963), a solid-liquid coexistence state can be _achieved at 280 ° C., which is the lowest heat storage temperature T _min .

  When a binary mixed salt having a non-eutectic composition as described above is used as the heat storage material 2, the solid phase of the heat storage material 2 generated by solidification around the heat transfer tubes 4a, 4b, 4c for heat dissipation becomes a cooling surface. It does not adhere strongly to the surface of the heat transfer tubes 4a, 4b, 4c, which are heat transfer surfaces, and easily comes off.

  This is because the solid fraction near the cooling surface increases locally when it begins to solidify, so that the molten salt forming a liquid phase with a relatively low melting point enters between the cooling surface and the solid phase. This is thought to be due to the progress of solidification, and is attributed to the existence of a solid-liquid coexistence region of non-eutectic molten salt with a temperature range.

  Therefore, the heat storage system of this embodiment is controlled so that the solid phase gradually increases from the liquid phase state of the heat storage material 2 in the heat storage tanks 1a, 1b, and 1c, that is, the temperature is gradually decreased. It is possible to suppress the heat storage material 2 that has become a solid phase from sticking (adhering) to the surfaces of the heat transfer tubes 4a, 4b, 4c for heat radiation.

  Each heat storage tank 1a, 1b, 1c is provided with, for example, a temperature measuring device as the heat storage amount measuring means 6a, 6b, 6c. The number of temperature measurement points may be either singular or plural, and the arrangement of the temperature measurement points may be set as appropriate. In this case, if a test or the like is performed and the correlation between the temperature measurement results by the heat storage amount measuring means 6a, 6b, 6c and the heat storage amount of the heat storage tanks 1a, 1b, 1c is obtained in advance, the temperature measurement results From this, it is possible to measure (estimate) the amount of heat storage. The heat storage amount measuring means 6 a, 6 b, 6 c are configured to send the temperature measurement result to the control device 7.

  The control device 7 performs heat storage heat treatment shown in a flow chart in FIG. 2 based on inputs from the heat storage amount measuring means 6a, 6b, 6c.

The control device 7 is set with a reference value that is a criterion for determining that each of the heat storage tanks 1a, 1b, and 1c is in a high heat storage state (step S1). For example, when the temperature measurement result is input from the heat storage amount measuring means 6a, 6b, 6c to the control device 7, this reference value may be set according to the temperature value. This compares the input value with the reference value. It is preferable in that it can be easily performed. In addition, although it is preferable that the high heat storage state of each heat storage tank 1a, 1b, 1c is the heat storage state used as the heat storage maximum temperature _Tmax , it is not necessarily limited to the heat storage state used as the heat storage maximum temperature _Tmax. .

  In this state, the control device 7 starts heat storage heat treatment (step S2). When the heat storage heat treatment is started, the temperature measurement result is input to the control device 7 from the heat storage amount measuring means 6a, 6b, 6c (step S3).

When this input is performed, the control device 7 first stores the heat storage tank 1c in the heat dissipation tank 1c whose heat dissipation heat medium distribution order (n = 1, 2, 3) is last (n = n _max , here n = 3) as a heat storage target. (Step S4), whether or not the heat storage tank 1c that is the target of heat storage is in a high heat storage state by comparing the temperature measurement result input from the heat storage amount measuring means 6c with a set reference value Is determined (step S5).

  In step S5, when the temperature measurement result for the heat storage tank 1c does not reach the reference value and it is determined that the heat storage tank 1c is not in the high heat storage state, the control device 7 proceeds to step S6, at which time The heat storage to the heat storage tank 1c that is the target of heat storage is performed. Specifically, the control device 7 opens only the on-off valve 13c of the heat storage tank 1c as shown in FIG. 3A for the on-off valves 13a, 13b, 13c that are normally all closed. . In FIGS. 3A, 3B, and 3C, for convenience of illustration, the open / close valve 13c that has been opened is shown in white, and the open / close valves 13a and 13b in the closed state are shown in black (FIG. 4). The same applies to (a), (b) and (c).

  As a result, in the heat storage tank 1c, the heating heat medium 11 guided through the heating heat medium supply line 12 flows through the heat medium flow path 10, so that the heat storage material 2 is heated by the heating means 3c. Thus, heat storage in the heat storage tank 1c is started.

  If the control apparatus 7 starts the heat storage to the heat storage tank 1c of heat storage object in step S6, it will return to step S5 and will be step S5 and step S6 until it is judged that the heat storage tank 1c is a high heat storage state. These processing loops are sequentially repeated to store heat in the heat storage tank 1c.

  On the other hand, when it is determined that the heat storage tank 1c is in the high heat storage state when the control device 7 first proceeds from step S4 to step S5, or as a result of the heat storage heat treatment in step S6, the heat storage tank 1c is determined in step S5. When it is determined that is in a high heat storage state, the process proceeds to step S7. At this time, if the heat storage heat treatment in step S6 has been performed, the control device 7 closes the on-off valve 13c of the heat storage tank 1c and stops the heat storage heat treatment of the heat storage tank 1c.

  In step S7, the control device 7 determines whether or not the heat storage tank 1c that is the target of heat storage at that time is the first (n = 1) heat storage tank in the heat-dissipation heat medium distribution sequence, that is, the present embodiment. Then, it is determined whether or not it is the heat storage tank 1a, and if the heat storage target is not the first heat storage tank 1a in the heat-dissipation heat medium distribution sequence, the process proceeds to step S8.

  In step S8, the control device 7 performs an update for selecting the heat storage tank 1b whose heat dissipation heat medium circulation order is one previous (n = n−1) as the heat storage target, and then returns to step S5.

  Thereby, about the heat storage tank 1b newly made into the heat storage object, the process after step S5 mentioned above is started similarly to the case of the heat storage tank 1c. In addition, when the heat storage tank 1b becomes a heat storage object in this way, the heat storage tank 1c after the heat medium circulation sequence for heat radiation is in a high heat storage state.

  In step S5, when the temperature measurement result input from the heat storage amount measuring unit 6b does not reach the reference value and it is determined that the heat storage tank 1b is not in the high heat storage state, the control device 7 proceeds to step S6. The heat storage to the heat storage tank 1b is carried out. Specifically, as shown in FIG. 3B, the control device 7 opens only the on-off valve 13b of the heat storage tank 1b. As a result, in the heat storage tank 1b, the heating heat medium 11 guided through the heating heat medium supply line 12 flows through the heat medium flow path 10, so that the heat storage material 2 is heated by the heating means 3b. Thus, heat storage in the heat storage tank 1b is started.

  If the control apparatus 7 starts the heat storage to the heat storage tank 1b of heat storage object in step S6, it will return to step S5, and until it will be judged that the heat storage tank 1b is a high heat storage state, step S5 and step S6 These processing loops are sequentially repeated to store heat in the heat storage tank 1b.

  On the other hand, the control device 7 determines whether the heat storage tank 1b is the heat storage tank 1b at step S5, either at the time when the heat storage tank 1b is first subjected to heat storage or when the process first proceeds to step S5 or as a result of the heat storage heat treatment at step S6. If it is determined that is in a high heat storage state, the process proceeds to step S7. At this time, if the heat storage heat treatment in step S6 has been performed, the control device 7 closes the on-off valve 13b of the heat storage tank 1b and stops the heat storage heat treatment of the heat storage tank 1b.

  In step S7, the control device 7 determines that the heat storage tank 1b that is the heat storage target at that time is not the first (n = 1) heat storage tank 1a in the heat-dissipation heat medium distribution sequence. Proceed to S8.

  In step S8, the control apparatus 7 performs the update which selects the heat storage tank 1a with the heat | fever heat-distribution heat | fever distribution order one previous (n = n-1) as heat storage object, and returns to step S5 after that.

  Thereby, about the heat storage tank 1a newly made into the heat storage object, the process after step S5 mentioned above is started similarly to the case of the heat storage tank 1b. In addition, when this heat storage tank 1a becomes heat storage object, each heat storage tank 1b, 1c after the heat medium circulation sequence for thermal radiation is a high heat storage state.

  In step S5, when the temperature measurement result input from the heat storage amount measuring means 6a does not reach the reference value and it is determined that the heat storage tank 1a is not in the high heat storage state, the control device 7 proceeds to step S6. The heat storage to the heat storage tank 1a is carried out. Specifically, as shown in FIG. 3C, the control device 7 opens only the on-off valve 13a of the heat storage tank 1a. As a result, in the heat storage tank 1a, the heating heat medium 11 guided through the heating heat medium supply line 12 flows through the heat medium flow path 10, so that the heat storage material 2 is heated by the heating means 3a. Thus, heat storage in the heat storage tank 1a is started.

  If the control apparatus 7 starts the heat storage to the heat storage tank 1b of heat storage object in step S6, it will return to step S5 and will be step S5 and step S6 until it is judged that the heat storage tank 1a is a high heat storage state. These processing loops are sequentially repeated to store heat in the heat storage tank 1a.

  On the other hand, the control device 7 determines whether the heat storage tank 1a is the heat storage target at step S5, or the result of the heat storage heat treatment in step S6. If it is determined that the heat storage tank 1a is in the high heat storage state, the process proceeds to step S7. At this time, if the heat storage heat treatment in step S6 has been performed, the control device 7 closes the on-off valve 13a of the heat storage tank 1a and stops the heat storage heat treatment of the heat storage tank 1a.

  In step S <b> 7, the control device 7 determines that the heat storage tank 1 a that is a heat storage target at that time is the first heat storage tank 1 a in the heat dissipation heat medium distribution sequence (n = 1). In this case, since all the heat storage tanks 1a, 1b, 1c in the heat dissipation heat medium distribution sequence from the last to the first are in the high heat storage state, the control device 7 proceeds to step S9 and ends the heat storage heat treatment. .

  Furthermore, the control device 7 performs heat storage heat treatment at the start of heat dissipation when performing heat dissipation from each of the heat storage tanks 1a, 1b, and 1c at any time of heat storage heat treatment shown in the flowchart of FIG. Has the ability to interrupt. Then, when restarting the thermal storage heat processing to each thermal storage tank 1a, 1b, 1c, the control apparatus 7 is provided with the function to perform the process after step S2 of FIG.

  Thereby, in the heat storage system of this embodiment, when heat storage is performed on the plurality of heat storage tanks 1a, 1b, 1c to which the heat transfer tubes 4a, 4b, 4c are connected in series, the heat storage tanks 1a, 1b, 1c Even if the amount of heat storage varies, the heat storage from the last heat storage tank 1c in the heat dissipation heat medium distribution order to the high heat storage state one by one according to the reverse order of the heat dissipation heat medium distribution order. Is done.

  Next, the case where heat is dissipated from the plurality of heat storage tanks 1a, 1b, 1c whose heat storage amount is integrated and controlled by the control device as described above will be described with reference to FIGS. . In addition, description of the control apparatus 7 is abbreviate | omitted in FIG. 4 (a) (b) (c).

First, when each heat storage tank 1a, 1b, 1c is a high heat storage state, for example, as shown to Fig.4 (a), when each heat storage tank 1a, 1b, 1c is 400 _degreeC which is the heat storage maximum temperature _Tmax , The heat storage material 2 in each heat storage tank 1a, 1b, 1c is almost in a liquid phase. In this state, for example, when the heat-radiating heat medium 5 at 200 ° C. is supplied from the heat-dissipating heat medium supply line 16 to the heat-dissipating heat transfer tubes 4a, 4b, 4c, the heat-dissipating heat medium distribution sequence is the first heat storage tank 1a. Since the temperature of the heat dissipation heat medium 5 is lower than the temperature of the heat storage material 2, heat dissipation from the heat storage material 2 to the heat dissipation heat medium 5 proceeds according to the magnitude of the temperature difference between the two. Thereby, the heat-dissipating heat medium 5 that has passed through the heat-dissipating heat transfer tube 4a is heated to, for example, 350 ° C. by heat exchange with the heat storage material 2 having a high temperature of 400 ° C. in the heat storage tank 1a. At this time, in the heat storage tank 1a, when the temperature of the heat storage material 2 is partially lowered to 274 ° C. or less by heat exchange with the heat radiating heat medium 5 on the surface of the heat radiating heat transfer tube 4a, a solid phase is generated. Settles in the liquid phase.

  The heat-dissipating heat medium 5 that has passed through the heat-dissipating heat transfer pipe 4a is then sequentially supplied to the heat-dissipating heat transfer pipes 4b and 4c of the heat storage tanks 1b and 1c, which are later in the heat-dissipating heat medium distribution sequence. At this time, the heat dissipation heat medium 5 is already heated to a high temperature of 350 ° C. in the heat storage tank 1a. Therefore, in the heat storage tanks 1b and 1c, since the temperature difference between the temperature of the heat dissipation heat medium 5 and the temperature of the heat storage material 2 is reduced, the progress of heat dissipation from the heat storage material 2 to the heat dissipation heat medium 5 is suppressed. In the heat storage tanks 1b and 1c, the temperature drop of the heat storage material 2 is suppressed.

  Then, if supply of the heat-dissipating heat medium 5 is continued, in the heat storage tank 1a, when the temperature of the heat storage material 2 gradually decreases to 274 ° C. or less, as shown in FIG. The solid phase gradually increases and deposits. In this state, even if the heat-dissipating heat medium 5 flowing through the heat-dissipating heat transfer pipe 4a of the heat storage tank 1a is heated by heat exchange with the heat storage material 2 in the heat storage tank 1a, the temperature does not exceed 274 ° C. . FIG. 4B shows a state in which, for example, the temperature of the heat storage material 2 in the heat storage tank 1a is 270 ° C., and the heat dissipation heat medium 5 after passing through the heat transfer heat transfer tube 4a is 230 ° C.

  In this case, the temperature of the heat storage material 2 in the heat storage tank 1b is suppressed from 400 ° C. Therefore, the heat dissipation heat medium 5 supplied to the heat transfer heat transfer pipe 4b and the temperature of the heat storage material 2 in the heat storage tank 1b The temperature difference increases. Therefore, in this state, when the heat radiating heat medium 5 passes through the heat radiating heat transfer tube 4b, heat exchange with the heat storage material 2 having a high temperature of 400 ° C. in the heat storage tank 1b is performed. Until heated. At this time, in the heat storage tank 1b, when the temperature of the heat storage material 2 is partially lowered to 274 ° C. or less by heat exchange with the heat radiating heat medium 5 on the surface of the heat radiating heat transfer tube 4b, a solid phase is generated. Settles in the liquid phase.

  The heat-dissipating heat medium 5 that has passed through the heat-dissipating heat transfer tube 4b is then supplied to the heat-dissipating heat transfer tube 4c of the heat storage tank 1c in the next heat-dissipating heat medium distribution sequence. At this time, the heat-dissipating heat medium 5 is already heated to a high temperature of 350 ° C. when it passes through the heat storage tank 1b. For this reason, in the heat storage tank 1c, the temperature difference between the temperature of the heat dissipation heat medium 5 and the temperature of the heat storage material 2 is reduced, so that the progress of heat dissipation from the heat storage material 2 to the heat dissipation heat medium 5 is suppressed. In 1c, the temperature drop of the heat storage material 2 is suppressed.

  When the supply of the heat radiating heat medium 5 is further continued, the temperature of the heat storage material 2 further decreases in the heat storage tank 1a, and the solid phase ratio increases as shown in FIG. Further, in the heat storage tank 1b, when the temperature of the heat storage material 2 gradually decreases to 274 ° C. or lower, the solid phase of the heat storage material 2 gradually increases and accumulates as shown in FIG. In this state, even if the heat-dissipating heat medium 5 flowing through the heat-dissipating heat transfer pipe 4a of the heat storage tank 1a is heated by heat exchange with the heat storage material 2 in the heat storage tank 1a, the temperature does not exceed 274 ° C. . In FIG. 4C, for example, the temperature of the heat storage material 2 in the heat storage tank 1a is 250 ° C., the heat dissipation heat medium 5 after flowing through the heat transfer tube 4a is 220 ° C., and the temperature of the heat storage material 2 in the heat storage tank 1b. Shows a state in which the heat-dissipating heat medium 5 after flowing through the heat-dissipating heat transfer tube 4b reaches 250 ° C.

  Even in this case, the heat storage material 2 of the heat storage tank 1c is suppressed from lowering the temperature from 400 ° C., so the heat dissipation heat medium 5 supplied to the heat transfer heat transfer pipe 4c of the heat storage tank 1c and the heat storage tank The temperature difference with the temperature of the heat storage material 2 of 1c becomes large. Therefore, in this state, when the heat radiating heat medium 5 passes through the heat radiating heat transfer tube 4c, heat exchange with the heat storage material 2 having a high temperature of 400 ° C. in the heat storage tank 1c is performed. Until heated. At this time, in the heat storage tank 1c, when the temperature of the heat storage material 2 is partially lowered to 274 ° C. or less by heat exchange with the heat radiating heat medium 5 on the surface of the heat radiating heat transfer tube 4c, a solid phase is generated. Settles in the liquid phase.

  Thus, according to the heat storage system of the present embodiment, among the plurality of heat storage tanks 1a, 1b, 1c, the heat storage tanks 1a, 1b in which heat dissipation is mainly performed by heat exchange between the heat dissipation heat medium 5 and the heat storage material 2. , 1c can be changed in order from the first in order of circulation of the heat-dissipating heat medium. Therefore, since the heat storage tank 1c having the last heat-sink distribution sequence is supplied with the heat-sink tank 5a heated or preheated in the heat storage tank 1a or the heat storage tank 1b in the earlier heat-sink distribution order. The heat storage tank 1c can suppress heat radiation of the heat storage material 2 over a long period of time, and can maintain a high heat storage state in which the temperature of the heat storage material 2 is high.

  Moreover, as described above, when the heat storage system of the present embodiment starts the heat storage heat treatment at an arbitrary time of the heat dissipation treatment from the heat storage tanks 1a, 1b, 1c, the heat storage circulation sequence for heat dissipation is the last heat storage. In order from the tank 1c, heat storage is performed until a high heat storage state is reached. Also from this, the heat storage tank 1c with the last heat medium distribution sequence for heat dissipation can maintain the high heat storage state where the temperature of the heat storage material 2 is high for a long time.

  Therefore, according to the heat storage system of the present embodiment, the temperature of the heat-dissipating heat medium 5 that is finally taken out by heat exchange with the heat storage material 2 of the plurality of heat storage tanks 1a, 1b, 1c is increased over a long period of time. Can be achieved.

  Moreover, the heat storage system of this embodiment uses the heating heat medium 11 as a heat source for heating for heat storage of the heat storage material 2 of the heat storage tanks 1a, 1b, 1c. For this reason, the heat storage system of this embodiment is suitable for application to a power generation facility that uses natural energy to obtain high-temperature heat, such as solar thermal power generation, among power generation facilities that use natural energy. It can be.

[Second Embodiment]
FIG. 5 is a schematic cut side view showing a second embodiment of the heat storage system.

  5 that are the same as those shown in FIG. 1 are marked with the same symbols and descriptions of them will be omitted.

  As shown in FIG. 5, the heat storage system of the present embodiment has the same configuration as that shown in FIG. 1, the heating means 3 a, 3 b, 3 c of the heat storage tanks 1 a, 1 b, 1 c and the heating medium 11 as a heat source. Instead of the structure used as the electric heater, the electric heaters 20a, 20b, and 20c are used as the heat source.

  For this purpose, the heating means 3a, 3b, 3c of the heat storage tanks 1a, 1b, 1c in the present embodiment are disposed below the plate member 9 provided at the bottom of the tank internal space 8, and the electric heaters 20a, 20b, 20c. It has. The electric heaters 20a, 20b, and 20c are connected to a power supply device 21 that can individually operate power supply and power supply stop.

  Further, the control device 7 has a function of controlling the power supply device 21.

  Specifically, when the control device 7 performs heat storage heat treatment of the heat storage tanks 1a, 1b, and 1c according to the processing procedure similar to the processing procedure shown in the flowchart of FIG. 2, only the processing in step S6 is as follows. Has been changed.

  That is, in this embodiment, the control device 7 controls the power supply device 21 when performing heat storage in the heat storage tank 1c, the heat storage tank 1b, or the heat storage tank 1a currently selected as the heat storage object in step S6. And it has the function to supply electric power only to the electric heater 20c, the electric heater 20b, or the electric heater 20a of the heat storage tank 1c, the heat storage tank 1b, or the heat storage tank 1a to be stored.

  Therefore, also by the heat storage system of this embodiment, when performing heat storage heat processing, similarly to 1st Embodiment, the several heat storage tank 1a, 1b, 1c to which the heat exchanger tube 4a, 4b, 4c for heat radiation was connected in series was carried out. The heat storage from the last heat storage tank 1c in the heat dissipation heat medium distribution order to the high heat storage state can be performed one by one in accordance with the reverse order of the heat dissipation heat medium distribution order.

  The heat radiation process by the heat storage system of this embodiment is the same as that of 1st Embodiment.

  Therefore, according to the heat storage system of the present embodiment, the heat storage tank 1c with the last heat medium distribution sequence for heat dissipation can suppress heat dissipation of the heat storage material 2 over a long period of time, and the temperature of the heat storage material 2 is high. A high heat storage state can be maintained. Therefore, also by the heat storage system of this embodiment, the temperature of the heat-dissipating heat medium 5 that is finally taken out by exchanging heat with the heat storage material 2 of the plurality of heat storage tanks 1a, 1b, and 1c as in the first embodiment. The temperature can be increased for a long time.

  Moreover, the heat storage system of this embodiment uses the electric heaters 20a, 20b, and 20c as a heat source for heating for heat storage of the heat storage material 2 of the heat storage tanks 1a, 1b, and 1c. For this reason, the heat storage system of this embodiment is applied to a power generation facility that directly generates electricity using natural energy, such as solar power generation or wind power generation, among power generation facilities using natural energy. It can be made suitable for.

  In addition, the heat storage system of each said embodiment is as a solid-phase peeling means for peeling off the solid-phase heat storage material 2 adhering to the surface of the heat exchanger tubes 4a, 4b, 4c for heat radiation in the heat storage tanks 1a, 1b, 1c. The same solid-state peeling means as that shown in Patent Document 2 may be provided. The solid phase peeling means is, for example, a type in which the heat storage material 2 in a solid phase is caused to flow from the surface of the heat radiating heat transfer tubes 4a, 4b, 4c by flowing the liquid heat storage material 2 with a circulation pump. Bubbles are generated below the heat transfer tubes 4a, 4b, and 4c for heat radiation 1a, 1b, and 1c, and the generated heat bubbles are peeled off from the surfaces of the heat transfer tubes 4a, 4b, and 4c for heat radiation by the generated bubbles. Type, heat slide tube insertion hole through which heat transfer tubes 4a, 4b, and 4c are passed, slide members with tapered tips, and slide members with bearings at the tips are used for heat radiation by actuators. If a reciprocating motion is made along the surfaces of the heat transfer tubes 4a, 4b, 4c, and the heat storage material 2 that has become a solid phase is mechanically peeled off from the surfaces of the heat transfer tubes 4a, 4b, 4c, etc. Good.

  Further, the present invention is not limited to the embodiments described above, and the vertical and radial dimensions of the heat storage tanks 1a, 1b, 1c shown in the drawings, the thickness of the heat transfer tubes 4a, 4b, 4c for heat radiation. The dimensions of the other parts are for convenience of illustration and do not reflect actual dimensions.

  1 and 4, the heat storage tanks 1a, 1b, and 1c have a configuration in which the heat radiating heat transfer tubes 4a, 4b, and 4c are disposed so as to penetrate the side walls, but the heat radiating heat transfer tubes 4a, 4b, The piping path 4c may be set arbitrarily.

  FIG. 1 shows a configuration in which a heating medium supply line 12 and a heating medium return line 14 are externally connected to the heating medium flow path 10 of the heating means 3a, 3b, 3c of the heat storage tanks 1a, 1b, 1c. However, one or both of the heating medium supply line 12 and the heating medium return line 14 may be arranged through the tanks of the heat storage tanks 1a, 1b, and 1c.

  The arrangement of the heat transfer tubes 4a, 4b, 4c near the top of the tank space 8 of the heat storage tanks 1a, 1b, 1c may be any arrangement other than those illustrated depending on the size, shape, etc. of the tank space 8. Good.

  As the heat storage material 2, it is preferable to use a material composed of the two-component mixed salt of the exemplified non-eutectic composition, but it causes a solid-liquid phase change in the heat storage temperature range of the heat storage tanks 1a, 1b, 1c. If the density of the solid phase is larger than the density of the liquid phase, a single component salt (molten salt), a mixed salt of three or more components of non-eutectic composition, a mixed salt of multiple components of eutectic composition, etc. Any heat storage material other than salt may be used.

  The heat storage temperature range may be freely changed according to the type of heat source and heat load.

  The heat storage tanks 1a, 1b, and 1c do not necessarily have a uniform heat storage capacity and configuration. The heat storage temperature range of each heat storage tank 1a, 1b, 1c does not necessarily have to be uniform.

  The heat storage tanks 1a, 1b, and 1c preferably include a heat storage material that causes a solid-liquid phase change in the heat storage temperature range, but may include a heat storage material that does not cause a phase change.

  The number of the plurality of heat storage tanks constituting the heat storage system of the present invention may be two or four or more.

  Of course, various modifications can be made without departing from the scope of the present invention.

1a, 1b, 1c Heat storage tank, 2 Heat storage material, 3a, 3b, 3c Heating means, 4a, 4b, 4c Heat dissipating tube, 5 Heat dissipating heat medium, 7 Controller, 10 Heat medium flow path, 11 Heating heat Medium, 12 Heating medium supply line for heating, 13a, 13b, 13c On-off valve, 20a, 20b, 20c Electric heater

Claims (4)

A heat storage material placed in the tank,
In the tank, a heat-radiating heat transfer tube that circulates a heat-dissipating heat medium having a temperature lower than that of the heat storage material and performs heat exchange with the heat storage material,
A heating means provided in the heat storage tank for heating the heat storage material for heat storage;
A plurality of heat storage tanks having
The plurality of heat storage tanks are connected in series so that the heat-dissipating heat transfer tube flows in order through the heat-dissipating heat medium,
And a control device for controlling the heating means of the plurality of heat storage tanks,
When the control device performs heat storage on the plurality of heat storage tanks in which the heat radiating heat transfer tubes are connected in series, the heat radiating heat medium flows through the heat radiating heat transfer tubes connected in series. A function of individually performing heat storage from the heat storage tank in which the heat dissipation heat medium distribution order is last to the high heat storage state set in each of the plurality of heat storage tanks in the reverse order of the heat dissipation heat medium distribution order. A heat storage system characterized by comprising. The heat storage material shall produce a solid-liquid phase change in the heat storage temperature range of the heat storage tank,
Each said heat storage tank is equipped with the said heating means in the bottom part side of the space in the tank which put the said thermal storage material, and is equipped with the said heat-radiation heat exchanger tube near the upper part of the said space in a tank. Heat storage system. The heating means of each heat storage tank includes a heat medium flow path for circulating a heat medium for heating, and the heat medium flow path is connected to a heating heat medium supply line via an on-off valve,
The heat storage system according to claim 2, wherein the control device has a function of individually opening and closing the on-off valve for each of the heat medium flow paths of the heat storage tanks. The heating means of each heat storage tank includes an electric heater,
The said control apparatus is provided with the function to operate separately the electric power feeding and electric power feeding stop for every said electric heater of each said heat storage tank. The heat storage system of Claim 2 characterized by these.

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