Energy storage device

Provided is an energy storage device, including: a first heat exchanger configured to exchange heat between gas and solid particles; a gas supplier configured to supply gas to the first heat exchanger; a heater configured to consume power to heat any one of or both of gas fed from the gas supplier to be supplied to the first heat exchanger and gas present in the first heat exchanger; a solid-gas separator configured to separate gas and solid in a solid-gas mixture discharged from the first heat exchanger; a high-temperature tank and a low-temperature tank each configured to store the solid particles separated by the solid-gas separator; a first heat utilization device configured to use thermal energy of the gas separated by the solid-gas separator; a high-temperature particle supplier configured to supply the solid particles stored in the high-temperature tank to the first heat exchanger; and a low-temperature particle supplier configured to supply the solid particles stored in the low-temperature tank to the first heat exchanger.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of priority to Japanese Patent Application No. 2017-221076 filed on Nov. 16, 2017, and contents thereof are incorporated herein.

BACKGROUND ART

Technical Field

The present disclosure relates to an energy storage device.

Related Art

An amount of generated power (hereinafter referred to as “generated power amount”) and an amount of demand power (hereinafter referred to as “demand power amount”) do not always match. Therefore, surplus power may be generated (“generated power amount”−“demand power amount”>0) or power may be required (“generated power amount”−“demand power amount”<0, for example, power shortage occurs) in some cases. Particularly in power generation using renewable energy such as wind power generation and solar power generation, the amount of surplus power and the amount of power shortage are large.

In view of this, there has been developed a device including a brick block containing electric heaters and having flow paths formed therein (for example, Patent Literature 1). In the technology of Patent Literature 1, the electric heaters are driven when surplus power is generated so as to heat the brick block to store the heat. Then, in the technology of Patent Literature 1, when power is required (for example, when power shortage occurs), water is caused to flow through the flow paths so that the water is heated by the stored heat. Subsequently, in the technology of Patent Literature 1, power is generated by rotating a turbine through use of the heated water (steam).

CITATION LIST

Patent Literature

Patent Literature 1: US 2008/0219651 A

SUMMARY

Technical Problem

In order to stabilize a power grid (to achieve a smart grid), there is known a technology of converting surplus power into heat and storing the heat so that the stored heat can be used as required. In this technology, there is a demand for development in a technology of efficiently storing the heat or efficiently using the stored heat.

The present disclosure has been made in view of the above-mentioned problems, and has an object to provide an energy storage device capable of converting power into heat and efficiently storing the heat so that the heat can be efficiently used as required.

Solution to Problem

In order to solve the above-mentioned problem, according to the present disclosure, there is provided an energy storage device, including: a first heat exchanger to be supplied with gas from a gas supply port formed in a bottom surface or a lower portion of the first heat exchanger, and to be supplied with solid particles from above the gas supply port, the first heat exchanger being configured to exchange heat between the gas and the solid particles; a gas supplier configured to supply gas to the first heat exchanger; a heater configured to consume power to heat any one of or both of gas fed from the gas supplier to be supplied to the first heat exchanger and gas present in the first heat exchanger; a solid-gas separator configured to separate gas and solid in a solid-gas mixture discharged from the first heat exchanger; a high-temperature tank and a low-temperature tank each configured to store the solid particles separated by the solid-gas separator; a first heat utilization device configured to use thermal energy of the gas separated by the solid-gas separator; a high-temperature particle supplier configured to supply the solid particles stored in the high-temperature tank to the first heat exchanger; and a low-temperature particle supplier configured to supply the solid particles stored in the low-temperature tank to the first heat exchanger.

The energy storage device may further include a controller configured to control the gas supplier, the heater, and the low-temperature particle supplier, wherein the controller may be configured to, in a predetermined heat storage mode: control the gas supplier to supply gas to the first heat exchanger; drive the heater to heat the gas; and control the low-temperature particle supplier to supply the solid particles from the low-temperature tank to the first heat exchanger, so that the solid particles are heated by the gas in the first heat exchanger, and the solid particles separated by the solid-gas separator are supplied to the high-temperature tank.

The controller may be configured to, in the heat storage mode, adjust an amount of the solid particles to be supplied by the low-temperature particle supplier based on a predetermined surplus power amount.

The gas supplier may be configured to, in the heat storage mode, cause the gas to pass through the solid particles stored in the low-temperature tank, and then supply the gas to the first heat exchanger.

The energy storage device may further include a controller configured to control the gas supplier, the heater, and the high-temperature particle supplier, wherein the controller may be configured to, in a predetermined heat radiation mode: stop the heater; control the gas supplier to supply gas to the first heat exchanger; and control the high-temperature particle supplier to supply the solid particles from the high-temperature tank to the first heat exchanger, so that the gas is heated by the solid particles in the first heat exchanger, the solid particles separated by the solid-gas separator are supplied to the low-temperature tank, and the gas separated by the solid-gas separator is supplied to the first heat utilization device.

The gas supplier may be configured to, in the heat radiation mode, cause the gas to pass through the solid particles stored in the low-temperature tank, and then supply the gas to the first heat exchanger.

The controller may be configured to, in the heat radiation mode, adjust an amount of the solid particles to be supplied by the high-temperature particle supplier based on a demand temperature of gas required by the first heat utilization device.

The controller may be configured to, in the heat radiation mode, control the low-temperature particle supplier to supply the solid particles from the low-temperature tank to the first heat exchanger.

Any one of or both of the high-temperature particle supplier and the low-temperature particle supplier may include: a plurality of pipes that differ in flow rates of solid particles passing therethrough; and a plurality of valves provided in the plurality of pipes, respectively, and wherein the controller may be configured to control opening and closing of each of the plurality of valves.

The low-temperature tank may include: a low-temperature accommodating portion for accommodating the solid particles; and a fluidizing gas supplier configured to supply fluidizing gas from a bottom surface or a lower portion of the low-temperature accommodating portion.

The heater may be provided at any one of or both of a wall of the first heat exchanger and an interior of the first heat exchanger.

The energy storage device may further include: a second heat exchanger configured to exchange heat between fluid and the solid particles separated by the solid-gas separator; and a fluid supplier configured to supply the fluid subjected to heat exchange by the second heat exchanger to any one of or both of the first heat utilization device and the second heat utilization device, wherein the low-temperature tank may be configured to store the solid particles subjected to heat exchange by the second heat exchanger.

The heater may be configured to consume power generated by any one of or both of a power generation system using renewable energy and a power generation system using a turbine generator.

Effects of Disclosure

According to the present disclosure, an energy storage device is capable of converting power into heat and efficiently storing the heat so that the heat can be efficiently used as required.

DESCRIPTION OF EMBODIMENTS

Now, with reference to the attached drawings, one embodiment of the present disclosure is described in detail. The dimensions, materials, and other specific numerical values represented in the embodiment are merely examples used for facilitating the understanding of the disclosure, and do not limit the present disclosure otherwise particularly noted. Elements having substantially the same functions and configurations herein and in the drawings are denoted by the same reference symbols to omit redundant description thereof. Further, illustration of elements with no direct relationship to the present disclosure is omitted.

FIG. 1is a view for illustrating an energy storage device100. As illustrated inFIG. 1, the energy storage device100includes a gas supplier110, a heating chamber120, a first heat exchanger130, a solid-gas separator140, a distributor142, a high-temperature tank150, a high-temperature particle supplier152, a low-temperature tank160, a low-temperature particle supplier162, a gas feeder170, a first heat utilization device180, a second heat exchanger190, a fluid supplier192, a second heat utilization device194, and a controller200. InFIG. 1, the solid-line arrows indicate a flow of solid particles and a solid-gas mixture. InFIG. 1, the broken-line arrows indicate a flow of fluid.

The gas supplier110supplies gas (for example, air) to the heating chamber120, which is described later. The gas supplier110includes a blower112, pipes114a,114b, and114c, valves116a,116b, and116c, and a blower116d. The blower112has an intake side connected to a gas supply source, and an ejection side connected to the pipe114a. The pipe114aconnects the blower112and the heating chamber120to each other. The valve116ais provided in the pipe114a. The pipe114bis branched from a portion between the blower112and the valve116ain the pipe114ato be connected to a wind box160bof the low-temperature tank160, which is described later. The valve116bis provided in the pipe114b. The pipe114cconnects a low-temperature accommodating portion160aof the low-temperature tank160, which is described later, and the heating chamber120to each other. The valve116cis provided in the pipe114c. The blower116dis provided on upstream of the valve116cin the pipe114c.

The heating chamber120includes a box member122and a heater124. The box member122is a hollow container. The box member122has an upper surface formed of a permeable distributor. The upper surface of the box member122also functions as a bottom surface of the first heat exchanger130, which is described later. The box member122is supplied with gas from the gas supplier110(blower112). The heater124consumes power to heat the gas. Examples of the heater124include a resistance heating device (device configured to use heat generated from a conductor supplied with power) and an arc heating device (device configured to use heat generated at the time of arc discharge).

The heater124can consume power generated by any one of or both of a power generation system using renewable energy and a power generation system using a turbine generator. Examples of the power generation system using renewable energy include a solar thermal power generation system, a solar power generation system, a wind power generation system, and a hydroelectric power generation system. When the heater124consumes power generated by the power generation system using renewable energy, power that often becomes surplus power can be efficiently converted into heat.

The heater124is arranged in the box member122. The heater124heats the gas supplied into the box member122. Therefore, when the heater124is driven, the gas supplied from the gas supplier110into the box member122is heated by the heater124, and is then supplied to the first heat exchanger130.

The first heat exchanger130is supplied with gas and solid particles from the bottom surface or a lower portion thereof, and exchanges heat between the gas and the solid particles. The solid particles are made of a material having a melting point that is higher than a demand temperature of the first heat utilization device180, which is described later.

Examples of the solid particles include silica, alumina, barite sand (barite or barium sulfate), partially calcined clay, glass beads, and collected petroleum catalyst. The solid particles are preferably any one of or both of silica and alumina. When the solid particles are silica, the cost required for the solid particles can be reduced. Further, when desert sand or river sand is used as the solid particles (silica), the solid particles are easily obtainable at low cost. Further, when the solid particles are alumina having a relatively high melting point, the temperature of the solid particles can be set high, and hence a high energy storage density can be achieved.

The solid particles are particles having a particle diameter of 0.01 mm or more and 10 mm or less. The shape of the solid particles is not limited, and may be a spherical shape or a shape other than the spherical shape.

In this embodiment, the first heat exchanger130is a hollow container. Inside the first heat exchanger130, a heater or a heat exchanger may be installed. The first heat exchanger130is supplied with solid particles from the high-temperature tank150and the low-temperature tank160, which are described later. Further, as described above, the first heat exchanger130is supplied with gas from the gas supplier110via the heating chamber120. A flow velocity of the gas to be supplied by the gas supplier110to the first heat exchanger130is equal to or larger than a terminal velocity of the solid particles in the first heat exchanger130. Further, the solid particles are supplied from above a gas supply port130aformed in the distributor arranged at the bottom surface of the first heat exchanger130. Therefore, the solid-gas mixture of solid particles and gas passes through the first heat exchanger130from a lower portion toward an upper portion (from the bottom surface toward an upper surface). Further, in the first heat exchanger130, the solid-gas mixture is formed of the solid particles and the gas, and the solid particles and the gas are strongly stirred. Therefore, the solid particles and the gas are efficiently brought into contact with each other to exchange heat therebetween.

The solid-gas separator140separates the solid and the gas of the solid-gas mixture discharged from the first heat exchanger130. Examples of the solid-gas separator140include a cyclone and a filter. The distributor142distributes the solid particles separated by the solid-gas separator140to the high-temperature tank150or the low-temperature tank160. The distributor142includes pipes144aand144band valves146aand146b. The pipe144aconnects a discharge port for discharging solid particles of the solid-gas separator140and the high-temperature tank150to each other. The valve146ais provided in the pipe144a. The pipe144bconnects the discharge port for discharging solid particles of the solid-gas separator140and the low-temperature tank160to each other. The valve146bis provided in the pipe144b. The valve146aand the valve146bare exclusively opened and closed by the controller200, which is described later.

The high-temperature tank150stores the solid particles separated by the solid-gas separator140. Examples of the high-temperature tank150include a hopper. The high-temperature particle supplier152supplies the solid particles stored in the high-temperature tank150to the first heat exchanger130. The high-temperature particle supplier152includes a pipe154and a flow rate adjustment valve156. The pipe154connects a lower portion of the high-temperature tank150and the lower portion of the first heat exchanger130to each other. The flow rate adjustment valve156is provided in the pipe154.

The low-temperature tank160stores the solid particles separated by the solid-gas separator140. The low-temperature tank160is supplied with the solid particles at a timing different from that of the high-temperature tank150. The low-temperature tank160includes the low-temperature accommodating portion160a, the wind box160b(fluidizing gas supplier), an exhaust pipe160c, and a check valve160d. The low-temperature accommodating portion160aaccommodates the solid particles supplied by the distributor142. The low-temperature accommodating portion160ais a hollow container. The wind box160bis provided below the low-temperature accommodating portion160a. An upper portion of the wind box160bis formed of a permeable distributor. The upper portion of the wind box160balso functions as a bottom surface of the low-temperature accommodating portion160a. The wind box160bis supplied with fluidizing gas (for example, air) from the gas supplier110(blower112) or the solid-gas separator140. The fluidizing gas supplied to the wind box160bis supplied into the low-temperature accommodating portion160afrom the bottom surface of the low-temperature accommodating portion160a(distributor).

The flow velocity of the fluidizing gas to be supplied from the gas supplier110to the low-temperature accommodating portion160ais equal to or larger than the minimum fluidization velocity of the solid particles and smaller than the scattering velocity of the solid particles. Further, the flow velocity of the fluidizing gas to be supplied from the solid-gas separator140to the low-temperature accommodating portion160ais equal to or larger than the minimum fluidization velocity of the solid particles and smaller than the terminal velocity of the solid particles. Therefore, the solid particles supplied from the solid-gas separator140is fluidized by the fluidizing gas to form a fluidized bed (bubbling fluidized bed) in the low-temperature accommodating portion160a. Further, the flow velocity of the fluidizing gas to be supplied from the solid-gas separator140to the low-temperature accommodating portion160ais smaller than the terminal velocity, and hence the solid particles do not scatter from the low-temperature accommodating portion160a.

The exhaust pipe160cconnects the low-temperature accommodating portion160aand a pressure energy collector160eto each other. The check valve160dis provided in the exhaust pipe160c. The check valve160dis opened when the pressure in the low-temperature accommodating portion160abecomes equal to or larger than a predetermined pressure. When the low-temperature accommodating portion160ais in a pressurized state, the pressure of the gas to be exhausted from the exhaust pipe160cis equal to or larger than the atmospheric pressure. In this case, the pressure energy collector160eis, for example, a turbine.

The low-temperature particle supplier162supplies the solid particles stored in the low-temperature tank160to the first heat exchanger130. The low-temperature particle supplier162includes a pipe164and a flow rate adjustment valve166. The pipe164connects a lower portion of the low-temperature accommodating portion160aand the lower portion of the first heat exchanger130to each other. The flow rate adjustment valve166is provided in the pipe164.

The gas feeder170supplies the gas separated by the solid-gas separator140to the first heat utilization device180or the wind box160b. The gas feeder170includes pipes172aand172band valves174aand174b. The pipe172aconnects a gas exhaust port of the solid-gas separator140and the first heat utilization device180to each other. The valve174ais provided in the pipe172a. The pipe172bconnects the gas exhaust port of the solid-gas separator140and the wind box160bto each other. The valve174bis provided in the pipe172b.

The first heat utilization device180is a device configured to use thermal energy of the gas separated by the solid-gas separator140. Examples of the first heat utilization device180include a gas turbine generator, a steam turbine generator (boiler), a boiler configured to provide steam, a fireplace (furnace or kiln), and an air conditioner.

The second heat exchanger190is provided between the valve146band the low-temperature accommodating portion160ain the pipe144b. The second heat exchanger190exchanges heat between the solid particles passing through the pipe144band fluid (for example, water, steam, air, and combustion exhaust gas). The second heat exchanger190may be configured to form a fluidized bed of solid particles, or may be configured to form a moving bed of solid particles. The second heat exchanger190includes a heat transfer pipe190a. The heat transfer pipe190apasses through the solid particles (through the fluidized bed or the moving bed of the solid particles). The fluid passes through the heat transfer pipe190a. The fluid supplier192causes the fluid to pass through the second heat exchanger190, and supplies the fluid subjected to heat exchange (heated) by the second heat exchanger190to the second heat utilization device194. The fluid supplier192is, for example, a pump.

The second heat utilization device194is a device configured to use thermal energy of the fluid heated by the second heat exchanger190. Examples of the second heat utilization device194include a gas turbine generator, a steam turbine generator (boiler), a boiler configured to provide steam, a fireplace (furnace or kiln), and an air conditioner.

The controller200is formed of a semiconductor integrated circuit including a central processing unit (CPU). The controller200reads out, for example, a program or parameters for operating the CPU itself from a ROM. The controller200cooperates with a RAM or other electronic circuits serving as a work area to manage and control the entire energy storage device100. In this embodiment, the controller200controls the gas supplier110(blower112, valves116a,116b, and116c, and blower116d), the heater124, the distributor142(valves146aand146b), the high-temperature particle supplier152(flow rate adjustment valve156), the low-temperature particle supplier162(flow rate adjustment valve166), the gas feeder170(valves174aand174b), and the fluid supplier192.

In this embodiment, during a period in which surplus power is generated (“generated power amount”−“demand power amount”>“predetermined value” (for example, 0)), the controller200converts the surplus power into thermal energy and stores the thermal energy (heat storage mode). On the other hand, when heat or power is required, the controller200causes the first heat utilization device180or the second heat utilization device194to use the stored thermal energy (heat radiation mode). In an initial state, the blowers112and116d, the heater124, and the fluid supplier192are stopped, and the valves116a,116b,116c,146a,146b,174a, and174band the flow rate adjustment valves156and166are closed. Further, in the initial state, the solid particles are stored in the low-temperature tank160(low-temperature accommodating portion160a). Now, processing to be performed by the controller200in each of the heat storage mode and the heat radiation mode is described.

FIG. 2is a view for illustrating the processing to be performed by the controller200in the heat storage mode. For ease of understanding, inFIG. 2, configurations not used in the heat storage mode are omitted.

The controller200closes the valves116b,116c,146b, and174aand the flow rate adjustment valve156. The controller200stops the blower116dand the fluid supplier192. Further, as illustrated inFIG. 2, the controller200drives the blower112and the heater124. Further, the controller200opens the valves116a,146a, and174b. The controller200opens the flow rate adjustment valve166and adjusts an opening degree of the flow rate adjustment valve166.

In this case, surplus power is consumed by the heater124. The gas supplied by the blower112to the heating chamber120is heated by the heater124. The heater124heats the gas to a predetermined first temperature, which is lower than a heat resistance temperature of the solid particles, and which satisfies the demand temperature of the first heat utilization device180. For example, the heater124heats the gas so that the solid particles heated by the gas are brought to a predetermined second temperature satisfying the demand temperature. When the solid particles are silica, the gas is heated to a temperature equal to or lower than 1,600° C. Further, the second temperature is lower than the first temperature, but the temperature difference therebetween is small (for example, about 50° C.).

The high-temperature gas (first-temperature gas) that has been heated as described above is supplied to the first heat exchanger130. Further, low-temperature solid particles are supplied from the low-temperature accommodating portion160ato the first heat exchanger130. Therefore, in the first heat exchanger130, the high-temperature gas and the low-temperature solid particles are strongly stirred, and heat is exchanged between the high-temperature gas and the low-temperature solid particles. In this manner, the solid particles are heated by the gas, and the gas is cooled by the solid particles. At the outlet of the first heat exchanger130, the temperature of the solid particles and the temperature of the gas become substantially equal to each other (become the second temperature).

Then, the solid-gas separator140separates the solid and the gas in the solid-gas mixture discharged from the first heat exchanger130. The separated high-temperature solid particles (second-temperature solid particles) are supplied to the high-temperature tank150through the pipe144a. The high-temperature tank150stores the high-temperature solid particles. On the other hand, the separated second-temperature gas is supplied to the wind box160bthrough the pipe172b. The second-temperature gas supplied to the wind box160bis used to fluidize the solid particles accommodated in the low-temperature accommodating portion160a. Further, with the second-temperature gas, the solid particles accommodated in the low-temperature accommodating portion160aare heated to a fourth temperature (fourth temperature is lower than a third temperature, which is described later, but higher than room temperature (for example, 25° C.)). That is, the solid particles accommodated in the low-temperature accommodating portion160acan collect part of heat of the gas discharged from the first heat exchanger130.

As described above, in the heat storage mode, surplus power is converted into heat, and the heat is first transferred to gas. Then, heat is exchanged between the high-temperature gas and the low-temperature solid particles so that heat is transferred to the solid particles. As described above, surplus power is converted into thermal energy, and the thermal energy is held (stored) by the solid particles. The heat capacity of the solid particles is larger than that of gas (air), and hence the heat storage density (J/m3) of the solid particles is higher than that of gas.

The controller200adjusts the opening degree of the flow rate adjustment valve166based on the amount of surplus power (hereinafter referred to as “surplus power amount”). Specifically, the amount of solid particles that are brought to the second temperature when the heater124converts the surplus power amount of power into thermal energy and heats the solid particles with this thermal energy (via the gas) is determined. Therefore, the controller200adjusts the opening degree of the flow rate adjustment valve166so that the determined amount of solid particles are supplied to the first heat exchanger130.

In this manner, even when the surplus power amount varies (the surplus power amount temporally varies), the temperature of the solid particles to be stored in the high-temperature tank150can be maintained regularly to the second temperature. That is, the variation of the surplus power amount can be coped with. Therefore, in the heat radiation mode to be described later, the third-temperature gas satisfying the demand temperature can be supplied to the first heat utilization device180even without use of additional energy (for example, without combustion of supplemental fuel).

FIG. 3is a view for illustrating the processing to be performed by the controller200in the heat radiation mode. For ease of understanding, inFIG. 3, configurations not used in the heat radiation mode are omitted.

The controller200closes the valves116a,146a, and174band the flow rate adjustment valve166. The controller200stops the heater124. Further, as illustrated inFIG. 3, the controller200opens the valves116b,116c,146b, and174a. Further, the controller200opens the flow rate adjustment valve156and adjusts an opening degree of the flow rate adjustment valve156. The controller200drives the blowers112and116dand the fluid supplier192.

In this manner, gas is supplied from the blower112through the low-temperature tank160and the box member122to the first heat exchanger130. The blower112supplies the gas at a demand flow rate of the first heat utilization device180. Further, the first heat exchanger130is supplied with the high-temperature solid particles (second-temperature solid particles) from the high-temperature tank150. Therefore, in the first heat exchanger130, heat is exchanged between the low-temperature gas and the high-temperature solid particles. In this manner, the gas is heated by the solid particles, and the solid particles are cooled by the gas. The solid particles and the gas are discharged from the first heat exchanger130at substantially equal temperatures, which are the third temperature.

Then, the solid-gas separator140separates the solid and the gas in the solid-gas mixture discharged from the first heat exchanger130. The separated high-temperature gas (third-temperature gas) is supplied to the first heat utilization device180through the pipe172a. The third temperature is a predetermined temperature satisfying the demand temperature of the first heat utilization device180, and is lower than the second temperature. In this manner, in the first heat utilization device180, the thermal energy of the gas is used (for example, power is generated). On the other hand, the separated third-temperature solid particles are supplied to the low-temperature tank160(low-temperature accommodating portion160a) through the pipe144b. The low-temperature tank160stores the third-temperature solid particles.

As described above, in the heat radiation mode, heat is exchanged between the high-temperature solid particles and the low-temperature gas so that the heat is transferred to the gas. Then, when required (for example, during a period in which power shortage occurs), the high-temperature gas (third-temperature gas) is used by the first heat utilization device180(for example, power is generated).

The controller200adjusts the opening degree of the flow rate adjustment valve156based on the demand temperature and the demand flow rate of the first heat utilization device180. Specifically, the amount of solid particles for heating the gas to the third temperature when the blower112supplies the gas at the demand flow rate of the first heat utilization device180and the second-temperature solid particles stored in the high-temperature tank150are used to heat the gas is determined. Therefore, the controller200adjusts the opening degree of the flow rate adjustment valve156so that the determined amount of solid particles are supplied to the first heat exchanger130.

In this manner, the temperature of the gas to be supplied to the first heat utilization device180can be brought to the demand temperature of the first heat utilization device180. Therefore, the third-temperature gas satisfying the demand temperature can be stably supplied to the first heat utilization device180even without use of additional energy (for example, without combustion of supplemental fuel). Even when the demand temperature (for example, the demanded power generation amount) of the first heat utilization device180temporally varies, the variation can be coped with by adjusting the supply amount of the solid particles.

Further, the fluid supplier192causes fluid to pass through the heat transfer pipe190aof the second heat exchanger190. In this case, heat is exchanged between the fluid and the solid particles passing through the pipe144b. In this manner, the fluid heated by the solid particles is supplied to the second heat utilization device194. Then, the second heat utilization device194uses the heat of the fluid (heat of the solid particles separated by the solid-gas separator140). With this configuration including the second heat exchanger190and the fluid supplier192, heat of the solid particles obtained after the gas is heated to the third temperature can be effectively used.

Further, the blower112does not directly supply the gas to the heating chamber120(first heat exchanger130), but causes the gas to pass through the solid particles accommodated in the low-temperature accommodating portion160ato supply the gas to the first heat exchanger130(via the solid particles). In this manner, the gas supplied to the first heat exchanger130can be preheated by the solid particles having the fourth temperature (for example, about 300° C. or more and about 400° C. or less). As described above, when the heat of the solid particles accommodated in the low-temperature accommodating portion160ais used, the heat utilization efficiency can be improved. As a result, the output of the first heat utilization device180can be increased. For example, when the first heat utilization device180is a steam turbine generator or a gas turbine generator, the power generation efficiency can be improved.

As described above, the energy storage device100according to this embodiment converts surplus power into thermal energy and causes the solid particles to keep the thermal energy. In this manner, as compared to the related art configured to store the surplus power in a secondary battery or the related art configured to convert the surplus power into hydrogen, the energy can be kept at lower cost. Further, as compared to the related art configured to convert the surplus power into hydrogen to keep the energy, the kept energy can be converted into thermal energy or electric energy at higher speed as required (for example, when power shortage occurs).

Further, as compared to the related art configured to store heat with use of a brick block, in the heat storage mode, through adjustment of the amount of solid particles for storing heat, the solid particles having the designated second temperature can be stored even when surplus power varies. Further, in the heat radiation mode, the flow rate of the gas to be supplied by the blower112is set to the demand flow rate of the first heat utilization device180, and the amount of solid particles to be supplied to the first heat exchanger130is adjusted. In this manner, the temperature of the gas to be supplied to the first heat utilization device180can be brought to the demand temperature of the first heat utilization device180. Therefore, without use of supplemental fuel, temporal load variation of the first heat utilization device180can be coped with.

First Modification Example

In the above-mentioned embodiment, description has been given of an example of a configuration in which the flow rate adjustment valves156and166are mechanical valves (butterfly valves) whose opening degrees are adjustable. However, the flow rate adjustment valves156and166are not limited to this configuration as long as the flow rate of the solid particles passing therethrough can be adjusted.

FIG. 4is a view for illustrating a flow rate adjustment valve310in a first modification example. In this case, description is given of an example of a case in which the flow rate adjustment valve310is provided in place of the flow rate adjustment valve156. However, the flow rate adjustment valve310may be provided in place of the flow rate adjustment valve166.

As illustrated inFIG. 4, the flow rate adjustment valve310is an L-valve loop seal. Specifically, the flow rate adjustment valve310includes a vertical pipe312, a horizontal pipe314, a connection pipe316, and a fluidizing gas supplier318. The vertical pipe312is a pipe extending in the vertical direction. The vertical pipe312has an upper end connected to the high-temperature tank150. The horizontal pipe314is a pipe extending in the horizontal direction. The horizontal pipe314is continuous with the vertical pipe312. That is, the vertical pipe312and the horizontal pipe314form an L-shaped pipe. The connection pipe316is continuous with the horizontal pipe314. The connection pipe316is connected to the first heat exchanger130.

The fluidizing gas supplier318supplies gas to the vertical pipe312or the horizontal pipe314. The fluidizing gas supplier318includes a nozzle318aand a pump318b. The nozzle318ahas an opening oriented so as to face the horizontal pipe314. The pump318bsupplies gas to the nozzle318a.

At the flow rate adjustment valve310, the solid particles drop from the high-temperature tank150into the vertical pipe312to be deposited in the vertical pipe312and the horizontal pipe314. In this case, when gas is supplied by the fluidizing gas supplier318, the deposited solid particles are fluidized by the gas to be fed to the connection pipe316.

The pump318bis controlled by the controller200. The controller200controls the flow rate of the gas to be supplied by the pump318bso as to enable adjustment of the flow rate of the solid particles to be fed to the connection pipe316.

When the flow rate adjustment valve310is an L-valve loop seal (non-mechanical valve), the flow rate of the solid particles can be adjusted even when the solid particles have a high temperature. Further, the L-valve loop seal has a simple structure, and hence maintenance of the flow rate adjustment valve310can be easily performed.

Second Modification Example

FIG. 5is a view for illustrating a flow rate adjustment valve320in a second modification example. In this case, description is given of an example of a case in which the flow rate adjustment valve320is provided in place of the flow rate adjustment valve156. However, the flow rate adjustment valve320may be provided in place of the flow rate adjustment valve166.

As illustrated inFIG. 5, the flow rate adjustment valve320is a J-valve loop seal. Specifically, the flow rate adjustment valve320includes a vertical pipe322, a pot portion324, a connection pipe326, and a fluidizing gas supplier328.

The vertical pipe322is a pipe extending in the vertical direction. The vertical pipe322has an upper end connected to the high-temperature tank150, and a lower end connected to an inlet324aof the pot portion324. The pot portion324is a hollow container. The pot portion324has the inlet324aformed at its top. The pot portion324has an outlet324bformed in its side surface. The pot portion324includes a partition plate324cextending downward in the vertical direction from the top. The partition plate324cpartitions the inside of the pot portion324into a region in which the inlet324ais formed and a region in which the outlet324bis formed. Further, a distal end of the partition plate324cis extended to be lower than a lower end of the outlet324bin the vertical direction. The connection pipe326connects the outlet324bof the pot portion324and the first heat exchanger130to each other.

The fluidizing gas supplier328supplies gas from a bottom surface of the pot portion324. Specifically, the fluidizing gas supplier328includes a wind box328aand a pump328b. The wind box328ais provided below the pot portion324. An upper portion of the wind box328ais formed of a permeable distributor. The upper portion of the wind box328aalso functions as the bottom surface of the pot portion324. The wind box328ais supplied with fluidizing gas (air) from the pump328b. The fluidizing gas supplied to the wind box328ais supplied into the pot portion324from the bottom surface (distributor) of the pot portion324.

The flow velocity of the fluidizing gas to be supplied from the fluidizing gas supplier328to the pot portion324is equal to or larger than the minimum fluidization velocity of the solid particles and smaller than the scattering velocity of the solid particles. Therefore, the solid particles dropping from the high-temperature tank150through the vertical pipe322are fluidized by the fluidizing gas to form a fluidized bed (bubbling fluidized bed) in the pot portion324.

Then, as the solid particles are further introduced from the high-temperature tank150, the position of the fluidized bed in the vertical direction becomes higher. Then, the solid particles overflow from a lower end of the outlet324b, and are fed to the connection pipe326.

The on/off of the pump328bis controlled by the controller200. The controller200drives the pump328bso that the solid particles are fed from the high-temperature tank150to the connection pipe326. Further, the controller200stops the pump328bso that the feeding of the solid particles from the high-temperature tank150to the connection pipe326is stopped.

When the flow rate adjustment valve320is a J-valve loop seal (non-mechanical valve), the solid particles can be supplied even when the solid particles have a high temperature.

Third Modification Example

FIG. 6is a view for illustrating a particle supplier330in a third modification example. In this case, description is given of an example of a case in which the particle supplier330is provided in place of the high-temperature particle supplier152. However, the particle supplier330may be provided in place of the low-temperature particle supplier162.

As illustrated inFIG. 6, the particle supplier330includes a main pipe332, a plurality of sub-pipes334and336, and valves332a,334a, and336a. The main pipe332connects the high-temperature tank150and the first heat exchanger130to each other. The valve332ais provided in the main pipe332. The sub-pipe334connects the high-temperature tank150and a portion between the valve332aand the first heat exchanger130in the main pipe332to each other. The valve334ais provided in the sub-pipe334. The sub-pipe336connects the high-temperature tank150and a portion between the first heat exchanger130and a connection portion to the sub-pipe334in the main pipe332to each other. The valve336ais provided in the sub-pipe336.

The flow path sectional area of the main pipe332is larger than that of the sub-pipe334. The flow path sectional area of the sub-pipe334is larger than that of the sub-pipe336. Specifically, the flow path sectional area of the main pipe332is ½ of the flow path sectional area of the pipe154of the high-temperature particle supplier152. The flow path sectional area of the sub-pipe334is ¼ (½2) of the flow path sectional area of the pipe154. The flow path sectional area of the sub-pipe336is ⅛ (½3) of the flow path sectional area of the pipe154. That is, the main pipe332and the sub-pipes334and336differ in flow rate of the solid particles passing therethrough. For example, when the flow rate of the main pipe332is ½, the flow rate of the sub-pipe334is ¼, and the flow rate of the sub-pipe336is ⅛. The number of the sub-pipes336may be two.

The valves332a,334a, and336aare on-off valves. Each of the valves332a,334a, and336ais, for example, the J-valve loop seal described in the above-mentioned second modification example.

The opening and closing of the valves332a,334a, and336aare controlled by the controller200. The controller200is only required to control the opening or closing of any one of or a plurality of valves332a,334a, and336ato adjust the flow rate of the solid particles to be supplied from the high-temperature tank150to the first heat exchanger130.

The energy storage device may further include, when the flow rate of the main pipe332is ½, sub-pipes having flow rates of 1/16, 1/32, 1/64, . . . ½n(two sub-pipes having the flow rate of ½nmay be provided). In this manner, the flow rate of the solid particles to be supplied from the high-temperature tank150to the first heat exchanger130can be adjusted with higher accuracy.

Fourth Modification Example

FIG. 7Ais a view for illustrating a heater424in a fourth modification example.FIG. 7Bis a view for illustrating another heater524in the fourth modification example.FIG. 7Cis a view for illustrating further another heater624in the fourth modification example. In the fourth modification example, configurations substantially equal to the configurations described in the above-mentioned embodiment are denoted by the same reference symbols, and description thereof is omitted herein.

The heater424is an electric heater. As illustrated inFIG. 7A, the heater424is provided on an outer wall of the first heat exchanger130.

The heater524is an electric heater. As illustrated inFIG. 7B, the heater524is provided on an inner wall of the first heat exchanger130.

The heater624is an electric heater. As illustrated inFIG. 7C, the heater624is provided on an inner wall of the first heat exchanger130.

Each of the heaters424,524, and624is provided at least at the lower portion of the first heat exchanger130. The heating temperature of each of the heaters424,524, and624is lower than the heat resistance temperature of the box member122(heat resistance temperature of the distributor of the box member122).

The drive of each of the heaters424,524, and624is controlled by the controller200. Specifically, each of the heaters424,524, and624is driven in the heat storage mode, and is stopped in the heat radiation mode. When the energy storage device includes any one of the heaters424,524, and624, heat can be efficiently transferred to the solid particles.

Fifth Modification Example

Description has been given of an example of a case in which, in the heat storage mode of the above-mentioned embodiment, the fourth-temperature gas discharged from the low-temperature accommodating portion160aof the low-temperature tank160is supplied to the pressure energy collector160e. However, in the heat storage mode, the gas discharged from the low-temperature accommodating portion160amay be supplied to other configurations.

FIG. 8is a view for illustrating the processing to be performed by the controller200in the heat storage mode in a fifth modification example. For ease of understanding, inFIG. 8, configurations not used in the heat storage mode are omitted.

In the heat storage mode of the fifth modification example, the controller200closes the valves116b,146b, and174aand the flow rate adjustment valve156. The controller200stops the fluid supplier192. Further, as illustrated inFIG. 8, the controller200drives the blower112,116d, and the heater124. Further, the controller200opens the valves116a,116c,146a, and174b. The controller200opens the flow rate adjustment valve166and adjusts an opening degree of the flow rate adjustment valve166.

In this case, in addition to the gas supplied by the blower112, the gas discharged from the low-temperature tank160(low-temperature accommodating portion160a) is supplied to the heating chamber120. That is, the gas supplier110causes the gas to pass through the solid particles stored in the low-temperature tank160, and then supplies the gas to the first heat exchanger130. In this manner, the gas that has been preheated by the low-temperature tank160can be supplied to the first heat exchanger130. Therefore, the gas supplier110can collect the heat of the gas discharged from the first heat exchanger130, which has not been able to be collected by the solid particles accommodated in the low-temperature accommodating portion160a.

Sixth Modification Example

Description has been given of an example of a case in which, in the heat radiation mode of the above-mentioned embodiment, the solid particles are supplied to the first heat exchanger130only from the high-temperature tank150. However, solid particles may be supplied to the first heat exchanger130from other configurations.

FIG. 9is a view for illustrating the processing to be performed by the controller200in the heat radiation mode in a sixth modification example. For ease of understanding, inFIG. 9, configurations not used in the heat radiation mode are omitted.

In the heat radiation mode of the sixth modification example, the controller200closes the valves116a,146a, and174b. The controller200stops the heater124. Further, as illustrated inFIG. 9, the controller200opens the valves116b,116c,146b, and174a. Further, the controller200opens the flow rate adjustment valves156and166and adjusts respective opening degrees of the flow rate adjustment valves156and166. The controller200drives the blowers112and116dand the fluid supplier192. That is, the controller200in the sixth modification example supplies, in the heat radiation mode, in addition to the solid particles stored in the high-temperature tank150, solid particles from the low-temperature tank160to the first heat exchanger130by controlling the low-temperature particle supplier162.

Further, the controller200adjusts the opening degrees of the flow rate adjustment valves156and166based on the demand temperature and the demand flow rate of the first heat utilization device180. Specifically, there are determined the amount of the second-temperature solid particles and the amount of the fourth-temperature solid particles for heating the gas to the third temperature when the blower112supplies the gas at the demand flow rate of the first heat utilization device180, and the gas is heated by the second-temperature solid particles stored in the high-temperature tank150and the fourth-temperature solid particles stored in the low-temperature tank160. Therefore, the controller200adjusts the opening degree of the flow rate adjustment valve156so that the determined amount of second-temperature solid particles are supplied to the first heat exchanger130. Further, the controller200adjusts the opening degree of the flow rate adjustment valve166so that the determined amount of fourth-temperature solid particles are supplied to the first heat exchanger130.

As described above, in the heat radiation mode, the controller200supplies the solid particles to the first heat exchanger130from the high-temperature tank150and the low-temperature tank160. In this manner, as compared to the case in which the solid particles are supplied only from the high-temperature tank150, a time period of supplying the solid particles can be extended. That is, the first heat exchanger130can extend a time period of exchanging heat between the solid particles and the gas. Therefore, the gas feeder170can supply the third-temperature gas to the first heat utilization device180for a long time period. As a result, the first heat utilization device180can be operated for a long time period.

The embodiment has been described above with reference to the attached drawings, but, needless to say, the present disclosure is not limited to the above-mentioned embodiment. It is apparent that those skilled in the art may arrive at various alternations and modifications within the scope of claims, and those examples are construed as naturally falling within the technical scope of the present disclosure.

For example, in the above-mentioned embodiment, description has been given of an example in which air is supplied as the gas to be supplied by the gas supplier110. However, the gas to be supplied by the gas supplier110is not limited thereto. The gas supplier110may supply, for example, carbon dioxide or combustion exhaust gas.

Further, in the above-mentioned embodiment, description has been given of an example of a configuration in which the gas supplier110includes the blower112. However, the configuration of the gas supplier110is not limited as long as the gas supplier110can supply the gas to the first heat exchanger130. For example, the gas supplier110may include a compressed gas source (for example, compressed air source) or a pump in place of the blower112.

Further, in the above-mentioned embodiment, description has been given of an example of a configuration in which the gas is supplied from the bottom surface of the first heat exchanger130. However, the gas (air) is only required to be supplied from a portion lower than a portion for supplying the solid particles of the first heat exchanger130. For example, the gas (air) may be supplied from a lower portion of the first heat exchanger130. Further, the gas supplier110may supply gas having a normal pressure, or may supply pressurized gas.

Further, in the above-mentioned embodiment, description has been given of an example of a case in which the fluid supplier192supplies fluid subjected to heat exchange by the second heat exchanger190to the second heat utilization device194. However, the fluid supplier192may supply the fluid subjected to heat exchange by the second heat exchanger190to the first heat utilization device180in place of or in addition to the second heat utilization device194.

Further, in the above-mentioned embodiment, description has been given of an example of a configuration in which the low-temperature tank160stores the solid particles forming the fluidized bed. In this manner, the gas can be preheated efficiently by the heat of the solid particles in the heat radiation mode. However, the configuration of the low-temperature tank160is not limited as long as the low-temperature tank160can store the solid particles. The low-temperature tank160may be, for example, a hopper. Further, the low-temperature tank160may store the solid particles forming a moving bed.

Further, in the above-mentioned embodiment, description has been given of an example of a case in which the high-temperature tank150is a hopper. In this manner, heat radiation of the high-temperature solid particles can be suppressed. However, the configuration of the high-temperature tank150is not limited as long as the high-temperature tank150can store the solid particles. The high-temperature tank150may have a configuration in which, for example, similarly to the low-temperature tank160, the solid particles are stored as the fluidized bed.

Further, in the above-mentioned embodiment, the heat storage mode is performed during a period in which surplus power is generated (“generated power amount”−“demand power amount”>“predetermined value” (for example, 0)). However, the heat storage mode may be performed when power is required to be converted into other energy (for example, when power is required to be consumed in order to stabilize the power grid). Further, the heat radiation mode is performed as required. However, the heat radiation mode may be performed when heat is required to be used (for example, when heat is desired to be used in a cement plant).

Further, in the above-mentioned embodiment, description has been given of an example of a configuration in which the energy storage device100includes the blower116d. However, the blower116dis not a necessary configuration. For example, in the heat radiation mode, the controller200is not required to drive the blower116d. Further, the energy storage device100may include a bypass pipe connected to the pipe114cto bypass the blower116d. In this case, in the heat storage mode, the controller200sets a path through which the gas passes to the path passing through the blower116d. Further, in the heat radiation mode, the controller200sets the path through which the gas passes to the path passing through the bypass pipe.

Further, description has been given of an example of a configuration in which, in the heat radiation mode of the above-mentioned embodiment, the controller200adjusts the opening degree of the flow rate adjustment valve156based on the demand temperature and the demand flow rate of the first heat utilization device180. However, the controller200may adjust the opening degree of the flow rate adjustment valve156based on the demand temperature of the first heat utilization device180. Similarly, in the sixth modification example, the controller200may adjust the opening degrees of the flow rate adjustment valves156and166based on the demand temperature of the first heat utilization device180.

Further, in the above-mentioned third modification example, description has been given of an example of a configuration in which two sub-pipes are provided. However, the number of sub-pipes is not limited thereto. The sub-pipes are only required to have different pipe diameters.

Further, the energy storage device100may include one or a plurality of heaters124,424,524, and624.

INDUSTRIAL APPLICABILITY

The present disclosure is applicable to an energy storage device.