Hydrogen utilization system and control method

Abstract

When supplying hydrogen to a fuel cell from a hydrogen storage alloy tank, the utilization efficiency of the hydrogen stored in the hydrogen storage alloy tank is increased. [Solution] The hydrogen utilization system comprises a hydrogen storage alloy tank, a first fuel cell connected to the hydrogen storage alloy tank and generating electricity using hydrogen supplied from the hydrogen storage alloy tank, a second fuel cell connected to the hydrogen storage alloy tank and generating electricity using hydrogen supplied from the hydrogen storage alloy tank, having a lower hydrogen demand pressure than the first fuel cell, and a control device that switches the fuel cell supplied with hydrogen from the hydrogen storage alloy tank based on the hydrogen pressure in the hydrogen storage alloy tank.

Description

Technical Field

[0001] The present invention relates to a hydrogen utilization system and a control method.

Background Art

[0002] There is a power supply system including a hydrogen energy storage facility that produces and stores hydrogen using surplus power from solar power generation and converts it into electricity when needed (see, for example, Patent Document 1). A hydrogen energy utilization system (power supply system) attached to a building efficiently uses surplus power from renewable energy such as solar power generation installed in the building to produce hydrogen. Then, for example, hydrogen produced safely and compactly is stored in a hydrogen storage tank using a flame-retardant hydrogen storage alloy. This stored hydrogen is converted into energy such as electricity and heat by fuel cell cogeneration as needed, and efficient energy management is implemented in combination with a storage battery, a heat storage system, and other building facilities. As a result, it becomes an important means for realizing a ZEB (Zero Energy Building) and can be expected to improve the Business Continuity Plan (BCP).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In addition to storing hydrogen produced within the building site (onsite), on the premise of constructing a hydrogen supply chain expected in the near future, the decarbonization of buildings and blocks and the creation of a disaster-resistant and resilient town can be promoted by the stored energy of hydrogen transported from outside the site (offsite) (hereinafter referred to as "imported hydrogen").

[0005] In the 2030s, when large-scale hydrogen utilization is expected to begin on both the supply and demand sides, infrastructure development such as hydrogen pipelines is likely to progress. If the use of imported hydrogen becomes commonplace, there will be no need for on-site hydrogen production, eliminating the need for hydrogen production equipment, which is one of the main pieces of equipment. The system configuration installed by the building will consist of fuel cells and hydrogen storage alloy tanks, leading to a reduction in the overall system cost. Furthermore, from the perspective of further cost reduction, the power generation capacity design and model selection, including how to combine the types and number of fuel cells, will become important. However, there are cases where the hydrogen pressure between the fuel cell and the hydrogen storage alloy tank is not matched, making it impossible to efficiently utilize the hydrogen stored in the hydrogen storage alloy tank.

[0006] The present invention has been made in view of these circumstances, and its purpose is to provide a hydrogen utilization system and control method that can improve the utilization efficiency of hydrogen stored in a hydrogen storage alloy tank when supplying hydrogen from a hydrogen storage alloy tank to a fuel cell. [Means for solving the problem]

[0007] To solve the above-mentioned problems, one aspect of the present invention is a hydrogen utilization system comprising: a hydrogen storage alloy tank; a first fuel cell connected to the hydrogen storage alloy tank and generating electricity using hydrogen supplied from the hydrogen storage alloy tank; a second fuel cell connected to the hydrogen storage alloy tank and generating electricity using hydrogen supplied from the hydrogen storage alloy tank, having a lower hydrogen demand pressure than the first fuel cell; and a control device that switches the fuel cell to which hydrogen is supplied from the hydrogen storage alloy tank based on the hydrogen pressure in the hydrogen storage alloy tank.

[0008] Furthermore, one aspect of the present invention is a control method for controlling the supply of hydrogen to a first fuel cell connected to a hydrogen storage alloy tank and generating electricity using hydrogen supplied from the hydrogen storage alloy tank, and to a second fuel cell having a lower hydrogen demand pressure than the first fuel cell, wherein the control method switches the fuel cell from which hydrogen is supplied from the hydrogen storage alloy tank based on the hydrogen pressure in the hydrogen storage alloy tank. [Effects of the Invention]

[0009] As explained above, this invention makes it possible to increase the utilization efficiency of hydrogen stored in a hydrogen storage alloy tank when supplying hydrogen to a fuel cell from the hydrogen storage alloy tank. [Brief explanation of the drawing]

[0010] [Figure 1] This figure shows the equipment configuration and energy flow of the power supply system according to this embodiment. [Figure 2] This is the chemical formula for hydrogen storage alloys, which absorb and release hydrogen. [Figure 3] This is an example of a PCT diagram showing the relationship between the hydrogen storage capacity and gas equilibrium pressure of a hydrogen storage alloy. [Figure 4] This diagram shows the configuration of the hydrogen utilization system included in the power supply system according to this embodiment. [Figure 5] This is a schematic block diagram showing the configuration of the control device in this embodiment. [Figure 6] This is a PCT diagram showing the hydrogen release state according to this embodiment. [Figure 7] This flowchart shows an example of the processing flow in the hydrogen utilization system according to this embodiment. [Modes for carrying out the invention]

[0011] The following describes a hydrogen utilization system and a control method for the hydrogen utilization system according to one embodiment of the present invention, with reference to the drawings.

[0012] FIG. 1 is a diagram showing the facility configuration and energy flow of the power supply system 100 according to the present embodiment. In FIG. 1, the first line is a route for directly supplying the generated power of solar power generation to the building 50, the second line is a route for temporarily storing surplus power in the storage battery 1 and supplying power to the building 50 as needed, and the third line is a route for producing hydrogen from surplus power, temporarily storing it in the hydrogen storage alloy tank 3, and converting it back to electricity and supplying it to the building 50.

[0013] In FIG. 1, PV (Photo Voltaics; solar power generation) 30 is a renewable energy power source that supplies renewable energy to the building 50, which is a consumer load, and outputs surplus power among the renewable energy to the storage battery 1 in the second line and the DC power supply 5 in the third line via the PCS (Power Conditioning System; power conditioner) 31. In the present embodiment, PV 30 is used as the renewable energy power source, but renewable energy may be generated using wind power generation or the like as the renewable energy power source.

[0014] The hydrogen production device 2 receives the battery discharge power P3” corresponding to the battery charging power P3 and the hydrogen production power P4 among the surplus power (battery charging power P3, hydrogen production power P4) output by the PV 30 from the DC power supply 5, and produces hydrogen using the received power. Then, the hydrogen production device 2 supplies the produced hydrogen to the hydrogen storage alloy tank 3. The hydrogen production device 2 may supply the produced hydrogen to the fuel cell 4. In the present embodiment, the hydrogen production device 2 supplies hydrogen to the hydrogen storage alloy tank 3 and the fuel cell 4.

[0015] The hydrogen storage alloy tank 3 uses a hydrogen storage alloy as a hydrogen storage medium, and stores the hydrogen produced by the hydrogen production device 2 by absorbing it into the hydrogen storage alloy. Further, when using the hydrogen stored in the hydrogen storage alloy as hydrogen energy, the hydrogen storage alloy tank 3 releases the hydrogen stored in the hydrogen storage alloy, for example, by heating.

[0016] The fuel cell 4 generates electricity using the hydrogen supplied from (released by) the hydrogen storage alloy tank 3, and supplies the generated electric power (fuel cell generated power P4”) to the building 50. Note that Fig. 1 shows the energy flow and does not necessarily match the connection of the facility configuration.

[0017] Here, when passing through the second and third lines involving energy conversion, the energy utilization efficiency decreases. However, the renewable energy passing through the second line can be short-term stored. The renewable energy passing through the third line can be reused when necessary by storing the electric power in the form of hydrogen. In the power supply system 100, as a key to system control, the smart BEMS (Building Energy Management System) 10 determines the value of the renewable energy that changes moment by moment, looks at the balance between demand and supply, appropriately determines the proportional distribution (proportional allocation) of energy conversion, and performs coordinated control of each facility.

[0018] One of the features of this power supply system 100 is that in the hydrogen storage alloy tank 3, a hydrogen storage alloy is used as the hydrogen storage medium. The characteristics of the hydrogen storage alloy of the Ti-Fe-based alloy used in the hydrogen storage alloy tank 3 in this embodiment can absorb a sufficient amount of hydrogen even at 20°C equivalent to the outside air temperature at a pressure less than 1 MPaG, which is the excluded range of application of the High Pressure Gas Safety Act (assuming an operating temperature of 30°C or higher considering energy savings during summer absorption), and can completely release hydrogen at 55 - 60°C corresponding to the exhaust heat temperature from the fuel cell 4. By automatically operating the hydrogen storage alloy tank 3 filled with such a hydrogen storage alloy and the fuel cell 4 through system control, system operation is possible without requiring a qualified person or an operator familiar with each facility. In this embodiment, as an example of the hydrogen storage alloy, the Ti-Fe-based alloy has been described, but as the hydrogen storage alloy, for example, various alloys such as alkaline earth-based, rare earth-based, titanium-based, and solid solutions may be used.

[0019] Figure 2 shows the chemical formula for hydrogen storage alloys when they absorb and release hydrogen. As this chemical formula shows, hydrogen storage alloys have a specific characteristic: they release heat when absorbing hydrogen and absorb heat when releasing hydrogen. Therefore, the hydrogen storage alloy tank 3 is driven by either "heat dissipation to the outside" or "heating from the outside". For this reason, the hydrogen storage alloy tank 3 is equipped with a heat exchange channel.

[0020] Figure 3 is an example of a PCT diagram showing the relationship between the hydrogen storage capacity and gas equilibrium pressure of a hydrogen storage alloy. The storage / release characteristics of a hydrogen storage alloy tank, which stores hydrogen gas compactly and safely, are represented by a PCT diagram showing the relationship between the hydrogen storage capacity and gas equilibrium pressure within the hydrogen storage alloy. In this PCT diagram, the horizontal axis represents the hydrogen storage capacity of the hydrogen storage alloy, and the vertical axis represents the hydrogen gas pressure (gas equilibrium pressure). In this PCT diagram, curve A1 shows the characteristics of the hydrogen storage alloy at temperature A degrees, and curve A2 schematically shows the characteristics at a higher temperature (A+α) degrees. Also, in this PCT diagram, the hydrogen gas pressure P emp This represents the lower limit of the usable range of hydrogen release pressure in hydrogen storage alloys, meaning that there is "empty" usable hydrogen. Also, in this PCT diagram, the hydrogen gas pressure P full This represents the upper limit pressure of the usable range for hydrogen release pressure in hydrogen storage alloys, and signifies that the hydrogen storage capacity is "full".

[0021] Here, let B be the hydrogen demand pressure of fuel cell 4. The hydrogen demand pressure is the pressure required to supply hydrogen to fuel cell 4, or the hydrogen pressure required to operate fuel cell 4. In this PCT diagram, the hydrogen storage alloy absorbs hydrogen when the temperature is A°C. The hydrogen storage alloy is heated to (A+α)°C, and the hydrogen gas pressure becomes equal to or greater than the hydrogen demand pressure B, thereby supplying hydrogen to fuel cell 4. However, if the hydrogen demand pressure B is relatively high (for example, the lower limit pressure P), emp Compared to the upper pressure P full In cases where it is close to the lower limit pressure P, a portion of the usable range of hydrogen release pressure in hydrogen storage alloys is used. empThe region from the hydrogen storage capacity to the hydrogen demand pressure B cannot be utilized. In this PCT diagram, the hydrogen storage alloy can only supply hydrogen to the fuel cell 4 from the state where the hydrogen storage capacity is "full" Q1 to the state where the hydrogen demand pressure is B Q2, and the amount supplied is limited. In other words, only a portion of the rated storage capacity (hydrogen storage amount) of the hydrogen storage alloy can be used for power generation by the fuel cell 4.

[0022] Two possible solutions to this problem are suggested, but both will increase the overall system cost. (Countermeasure 1) The hydrogen released from the storage alloy tank 3 is first pressurized to the hydrogen requirement pressure using a compressor or the like, and then supplied to the fuel cell 4. (Countermeasure 2) Install storage alloy tanks 3 with increased rated storage capacity by methods such as configuring multiple tanks as a set.

[0023] Therefore, the power supply system 100 in this embodiment employs a power generation capacity design that combines multiple fuel cells 4. Furthermore, in this embodiment, in order to reduce the overall cost of the system, the case in which "brought-in hydrogen," which is hydrogen transported from off-site, is used will be explained as an example.

[0024] Figure 4 shows the configuration of the hydrogen utilization system 100A included in the power supply system 100 according to this embodiment. The hydrogen utilization system 100A consists of a storage alloy tank 3, a fuel cell 4, a control device 70, and a heat supply system 80. The heat supply system 80 is a flow path, etc., for dissipating or absorbing heat from the storage alloy tank 3, the fuel cell 4, or the building 50.

[0025] When utilizing "brought-in hydrogen," which is hydrogen transported from off-site locations, small-scale hydrogen transport of several cranes (maximum 295 Nm3 per cradle) using transport vehicles such as Unic cranes (60) loaded with high-pressure hydrogen cranes is conceivable. When transferring from the high-pressure hydrogen cranes to the hydrogen storage alloy tank 3 on the building side, if the connection to the storage device exceeds two hours under the operation of the General High-Pressure Gas Safety Regulations, the building will be designated as a high-pressure gas storage facility. To avoid this situation, a rapid-filling tank will be used for the hydrogen storage alloy tank 3, which can complete the transfer within the remaining time after deducting the time required for parking the transport vehicle loaded with the high-pressure hydrogen cranes and connecting the piping. The rapid-filling tank incorporates a highly reactive heat removal mechanism, and hydrogen storage is promoted by cooling the hydrogen storage alloy inside the tank with a heat transfer medium.

[0026] In this embodiment, small-scale hydrogen transport is assumed using a transport vehicle 60 loaded with hydrogen cradles, etc., and a maximum of approximately 280 Nm3 of hydrogen is transferred to the hydrogen storage alloy tank 3 per trip. For this reason, the hydrogen storage alloy tank 3 is based on a rapid-filling tank assembly with a rated capacity of approximately 270 Nm3. Rapid-filling tanks come in small, medium, and large types with several rated storage capacities ranging from 10 to 90 Nm3, and tank assemblies can be constructed by combining these types.

[0027] Furthermore, in this embodiment, the hydrogen storage alloy tank 3 has a hydrogen release pressure of "0.1 to 0.2 MPaG" in the normal operating temperature range of 50 to 60°C. The hydrogen storage alloy tank 3 is equipped with a temperature sensor 33 that detects the temperature of the hydrogen storage alloy inside the tank 3 (hereinafter referred to as "tank temperature T") and a pressure sensor 32 that detects the pressure of the hydrogen stored in the tank 3 (hereinafter referred to as "hydrogen gas pressure P"). The hydrogen gas pressure corresponds to the hydrogen pressure inside the tank 3.

[0028] The fuel cell 4 comprises a first fuel cell 41 and a second fuel cell 42. The storage alloy tank 3 and the fuel cell 4 are connected by a hydrogen pipeline for supplying hydrogen from the storage alloy tank 3 to either the first fuel cell 41 or the second fuel cell 42. In the initial state, the hydrogen pipeline is connected so that hydrogen is supplied from the storage alloy tank 3 to the first fuel cell 41, which has a higher hydrogen demand pressure than the second fuel cell 42.

[0029] The first fuel cell 41 is a fuel cell with a relatively low cost and a hydrogen pressure requirement of approximately "0.6 to 0.99 MPaG". The rated output of the first fuel cell 41 is, for example, "35 to 50 kW".

[0030] The second fuel cell 42 is a fuel cell with a hydrogen demand pressure of approximately "0.05 to 0.1 MPaG", which is lower than that of the first fuel cell 41. The rated output of the second fuel cell 42 is, for example, "4.4 to 100 kW".

[0031] In this way, by combining a first fuel cell 41 with a relatively large rated output and a second fuel cell 42 with a lower hydrogen demand pressure than the first fuel cell 41 and controlling the number of units, a system can be constructed that has a power generation capacity suitable for the power consumption of a typical building 50 and can efficiently utilize hydrogen with a rapid-filling tank rated capacity of approximately 270 Nm3.

[0032] The control device 70 controls the switching of the fuel cell 4 to which hydrogen is supplied from the storage alloy tank 3. The control device 70 is communicated with the temperature sensor 33 and the pressure sensor 32 via a network or the like. The control device 70 may also be one of the functions of the smart BEMS 10 of the power supply system 100 in Figure 1.

[0033] Figure 5 is a schematic block diagram showing the configuration of the control device 70 in this embodiment. The control device 70 comprises a control unit 710, a communication unit 720, an input unit 730, a storage unit 740, and an output unit 750.

[0034] The control unit 710 has the function of controlling the overall operation of the control device 70. The control unit 710 is realized, for example, by causing the CPU (Central Processing Unit) provided as hardware in the control device 70 to execute a program. The control unit 710 includes a state acquisition unit 711 and a switching unit 712.

[0035] The status acquisition unit 711 acquires the tank temperature T and hydrogen gas pressure P from the temperature sensor 33 and pressure sensor 32 via the communication unit 720.

[0036] The switching unit 712 switches the fuel cells 4 that receive hydrogen from the storage alloy tank 3 based on the acquired hydrogen gas pressure P. For example, the switching unit 712 supplies hydrogen from the storage alloy tank 3 to the fuel cells with the highest hydrogen demand pressures required for hydrogen supply. More specifically, if the hydrogen gas pressure P is higher than a threshold based on the hydrogen demand pressure of the first fuel cell 41, the switching unit 712 supplies hydrogen from the storage alloy tank 3 to the first fuel cell 41. If the hydrogen gas pressure P is lower than the threshold, the switching unit 712 supplies hydrogen from the storage alloy tank 3 to the second fuel cell 42, which has a lower hydrogen demand pressure than the first fuel cell 41. The threshold is, for example, the hydrogen demand pressure of the first fuel cell 41. In this embodiment, the case where the threshold is the hydrogen demand pressure of the first fuel cell 41 is explained as an example, but the threshold is not limited to this, and any value close to the hydrogen demand pressure of the first fuel cell 41 is acceptable.

[0037] The communication unit 720 has the function of sending and receiving various types of information. The communication unit 720 communicates with external devices via wired or wireless connection. For example, the communication unit 720 communicates with the temperature sensor 33 and the pressure sensor 32 via a network or the like.

[0038] The input unit 730 has the function of receiving input from the user. The function of the input unit 730 is realized, for example, by a mouse, keyboard, buttons, touch panel, microphone, etc., provided by the control device 70.

[0039] The storage unit 740 has the function of storing various types of information. The storage unit 740 is composed of storage media provided as hardware by the control device 70, such as an HDD (Hard Disk Drive), SSD (Solid State Drive), flash memory, EEPROM (Electrically Erasable Programmable Read Only Memory), RAM (Random Access read / write Memory), ROM (Read Only Memory), or any combination of these storage media.

[0040] The output unit 750 has the function of outputting various types of information. The output unit 750 is composed of output devices provided as hardware by the control device 70, such as display devices such as a display device or a touch screen (touch panel), and audio output devices such as a speaker.

[0041] Next, the operation of the hydrogen utilization system 100A according to this embodiment will be described with reference to Figures 6 and 7.

[0042] Figure 6 is a PCT diagram showing the hydrogen release state according to this embodiment. In this PCT diagram, the horizontal axis represents the hydrogen storage amount of the hydrogen storage alloy, and the vertical axis represents the hydrogen gas pressure. In this PCT diagram, curve A11 shows the characteristics of the hydrogen storage alloy at temperature A degrees, and curve A12 schematically shows the characteristics at a higher temperature (A+α) degrees. Also, in this PCT diagram, the hydrogen gas pressure P emp This represents the lower limit pressure of the usable range for hydrogen release pressure in the hydrogen storage alloy of the storage alloy tank 3, meaning that the available hydrogen is "empty". Also, in this PCT diagram, the hydrogen gas pressure P full This is the upper limit pressure of the usable range of hydrogen release pressure in the hydrogen storage alloy of the storage alloy tank 3, and means that the hydrogen storage capacity is "full". Furthermore, let α be a threshold value based on the hydrogen demand pressure of the first fuel cell 41. The threshold value α is, for example, the hydrogen demand pressure of the first fuel cell 41.

[0043] Figure 7 is a flowchart showing an example of the processing flow in the hydrogen utilization system 100A according to this embodiment.

[0044] First, hydrogen is transferred from the transport vehicle 60 to the hydrogen storage alloy tank 3 while the temperature inside the tank is at A°C (step S101). At this time, the control unit 710 of the control device 70 uses the heat supply system 80 to suppress the temperature rise of the hydrogen storage alloy due to rapid filling by using cooling, thereby maintaining the temperature inside the hydrogen storage alloy tank 3 at A°C. As a result, the amount of hydrogen stored in the hydrogen storage alloy tank 3 increases along curve A11, from the "empty" state Q11 to the "full" state Q12 in the PCT diagram shown in Figure 6. After the hydrogen transfer is complete, the transport vehicle 60 departs.

[0045] Next, the control unit 710 of the control device 70 uses the heat supply system 80 to heat the hydrogen storage alloy to A+α°C and supply hydrogen to the first fuel cell 41 (step S102). As a result, hydrogen is released from the storage alloy tank 3 along the path of curve A12 from state Q21 to state Q22 in the PCT diagram shown in Figure 6, and hydrogen is supplied to the first fuel cell 41. At this time, the hydrogen gas pressure is higher than the hydrogen demand pressure of the first fuel cell 41, so combined heat and power generation by the first fuel cell 41 is possible. On the other hand, as hydrogen release continues in the storage alloy tank 3, the hydrogen gas pressure gradually decreases.

[0046] Next, the control unit 710 of the control device 70 determines whether the hydrogen gas pressure in the storage alloy tank 3 has fallen below the threshold α (step S103). If the hydrogen gas pressure is higher than the threshold α (step S103: No), the first fuel cell 41 can continue to operate, and the process returns to step S102.

[0047] On the other hand, if the hydrogen gas pressure falls below the hydrogen demand pressure of the first fuel cell 41, the first fuel cell 41 will become inoperable. Therefore, when the hydrogen gas pressure in the storage alloy tank 3 falls below a threshold (step S103: Yes), the control unit 710 of the control device 70 switches the hydrogen piping to stop the hydrogen supply to the first fuel cell 41 and starts supplying hydrogen to the standby second fuel cell 42 (step S104). As a result, hydrogen is released from the storage alloy tank 3 along the path of curve A12 from state Q22 to state Q23 in the PCT diagram shown in Figure 6, and hydrogen is supplied to the second fuel cell 42. As a result, the second fuel cell 42, whose hydrogen demand pressure is lower than that of the first fuel cell 41, performs combined heat and power generation.

[0048] Subsequently, when the hydrogen storage capacity of the storage alloy tank 3 becomes "empty," the control unit 710 of the control device 70 stops supplying hydrogen and shuts down the operation of the fuel cell 4. After that, the hydrogen utilization system 100A returns to the process of step S101 and performs rapid refueling of the incoming hydrogen again.

[0049] In this way, by constructing the hydrogen utilization system 100A with a rapid-filling hydrogen storage alloy tank 3 and a first fuel cell 41 with relatively low production costs, it is possible to reduce the overall cost of the hydrogen utilization system 100A and expand its use. Furthermore, by using the first fuel cell 41 in combination with a second fuel cell 42 that has a lower hydrogen demand pressure than the first fuel cell 41, the rated storage capacity of the rapid-filling hydrogen storage alloy tank 3 can be used efficiently for combined heat and power generation. As a result, the amount of energy generated equivalent to that required to make a city block or building a Zero Energy Building (ZEB) can be covered by the hydrogen brought in.

[0050] In the embodiment described above, the case of combining two fuel cells, the first fuel cell 41 and the second fuel cell 42, was explained as an example, but the invention is not limited to this, and three or more fuel cells with different hydrogen demand pressures may be combined. When three or more fuel cells are combined, the control device 70 switches the hydrogen piping so that hydrogen is supplied in order from the fuel cell with the highest hydrogen demand pressure.

[0051] As described above, the hydrogen utilization system 100A according to this embodiment comprises a storage alloy tank 3, a first fuel cell 41 connected to the storage alloy tank 3 and generating electricity using hydrogen supplied from the storage alloy tank 3, a second fuel cell 42 connected to the storage alloy tank 3 and generating electricity using hydrogen supplied from the storage alloy tank 3, having a lower hydrogen requirement pressure than the first fuel cell 41, and a control device 70 that switches the fuel cell 4 supplied with hydrogen from the storage alloy tank 3 based on the hydrogen pressure in the storage alloy tank 3.

[0052] With this configuration, the hydrogen utilization system 100A according to this embodiment can improve the utilization efficiency of the hydrogen stored in the storage alloy tank 3 when supplying hydrogen from the storage alloy tank 3 to the fuel cell 4.

[0053] For example, in the hydrogen utilization system 100A according to this embodiment, even if the hydrogen pressure of the first fuel cell 41 has a low compatibility ratio with the storage alloy tank 3, the hydrogen in the storage alloy tank 3 can be efficiently utilized by switching to the second fuel cell 42, which has a lower hydrogen demand pressure than the first fuel cell 41. In other words, even when using a fuel cell 4 with a relatively low compatibility ratio of hydrogen pressure with the storage alloy tank 3, the utilization efficiency of the hydrogen stored in the storage alloy tank 3 can be increased. This makes it possible to select fuel cells with lower production costs, contributing to a reduction in the overall cost of the hydrogen utilization system 100A and to the expansion of its use.

[0054] Furthermore, the hydrogen utilization system 100A according to this embodiment switches the fuel cell 4 supplied with hydrogen from the storage alloy tank 3 from the first fuel cell 41 to the second fuel cell 42 based on the hydrogen pressure in the storage alloy tank 3.

[0055] With this configuration, the hydrogen utilization system 100A according to this embodiment can utilize multiple fuel cells more efficiently.

[0056] Furthermore, in the hydrogen utilization system 100A according to this embodiment, if the hydrogen pressure in the storage alloy tank 3 is higher than the hydrogen demand pressure of the first fuel cell 41, hydrogen is supplied to the first fuel cell 41 from the storage alloy tank 3. If the hydrogen pressure in the storage alloy tank 3 is lower than the hydrogen demand pressure of the first fuel cell 41, hydrogen is supplied to the second fuel cell 42 from the storage alloy tank 3.

[0057] With this configuration, the hydrogen utilization system 100A according to this embodiment supplies hydrogen to the first fuel cell 41 as long as the hydrogen pressure is within the operating range of the first fuel cell 41. When the hydrogen pressure becomes such that the first fuel cell 41 cannot operate, the hydrogen supply is switched to the second fuel cell 42, which has a lower hydrogen requirement pressure than the first fuel cell 41. As a result, even if the hydrogen pressure in the storage alloy tank 3 falls below the hydrogen requirement pressure of the first fuel cell 41, the hydrogen in the storage alloy tank 3 can be supplied to the second fuel cell 42, allowing combined heat and power generation to continue with the hydrogen utilization system 100A. In other words, combined heat and power generation can be performed by the hydrogen utilization system 100A by utilizing the hydrogen in the storage alloy tank 3 more efficiently.

[0058] Furthermore, the hydrogen utilization system 100A according to this embodiment further comprises one or more fuel cells with different hydrogen requirement pressures from the first fuel cell 41 and the second fuel cell 42, and hydrogen is supplied from the storage alloy tank 3 in order from the fuel cell with the highest hydrogen requirement pressure. With this configuration, the hydrogen utilization system 100A according to this embodiment can utilize multiple fuel cells more efficiently, even when three or more fuel cells are combined.

[0059] In the embodiments described above, the control device 70 was described as being a terminal device such as a computer. However, at least one of the functions of the control device 70 may be provided on a server device connected to the terminal device via a communication network. In this case, the server device may be a physical server or a cloud server provided by a cloud computing service.

[0060] Some or all of the functions of the control device 70 in the above-described embodiment may be implemented by a computer. In that case, the functions may be implemented by recording a program for implementing these functions on a computer-readable recording medium, loading the program recorded on this recording medium into a computer system, and executing it. Here, "computer system" includes hardware such as an OS and peripheral devices. Furthermore, "computer-readable recording medium" refers to portable media such as flexible disks, magneto-optical disks, ROMs, CD-ROMs, and storage devices such as hard disks built into a computer system. In addition, "computer-readable recording medium" may also include those that dynamically hold programs for a short period of time, such as communication lines used when transmitting programs via networks such as the Internet or communication lines such as telephone lines, and those that hold programs for a certain period of time, such as volatile memory inside a computer system that acts as a server or client in such a case. Furthermore, the above-mentioned program may be for implementing some of the functions described above, or it may be a program that can implement the above-mentioned functions in combination with a program already recorded in the computer system, or it may be implemented using a programmable logic device such as an FPGA (Field Programmable Gate Array).

[0061] While embodiments of this invention have been described in detail above with reference to the drawings, the specific configuration is not limited to these embodiments and includes designs and the like that do not depart from the spirit of this invention. [Explanation of Symbols]

[0062] 1… Storage battery 2…Hydrogen production equipment 3… Storage alloy tank 4…Fuel cell 41…First fuel cell 42…Second fuel cell 5…DC power supply 10…Smart BEMS 20…grid power 30…PV 31...PCS 50... Buildings 70...Control device 710... Control Unit 711...Status acquisition unit 712... Switching section 720... Communications Department 730...Input section 740...Storage section 750...Output section 100…Power supply system 100A…Hydrogen utilization system

Claims

1. Hydrogen storage alloy tank and A first fuel cell connected to the hydrogen storage alloy tank and which generates electricity using hydrogen supplied from the hydrogen storage alloy tank, A second fuel cell, which has a lower hydrogen requirement pressure than the first fuel cell, is connected to the hydrogen storage alloy tank and generates electricity using hydrogen supplied from the hydrogen storage alloy tank. A control device that switches the fuel cell supplied with hydrogen from the hydrogen storage alloy tank based on the hydrogen pressure in the hydrogen storage alloy tank, A hydrogen utilization system equipped with the following features.

2. The control device is Based on the hydrogen pressure in the hydrogen storage alloy tank, the fuel cell supplied with hydrogen from the hydrogen storage alloy tank is switched from the first fuel cell to the second fuel cell. The hydrogen utilization system according to claim 1.

3. The control device is If the hydrogen pressure in the hydrogen storage alloy tank is higher than the hydrogen demand pressure of the first fuel cell, hydrogen is supplied to the first fuel cell from the hydrogen storage alloy tank. If the hydrogen pressure in the hydrogen storage alloy tank is lower than the hydrogen demand pressure of the first fuel cell, hydrogen is supplied to the second fuel cell from the hydrogen storage alloy tank. The hydrogen utilization system according to claim 1.

4. The system further comprises one or more fuel cells having different hydrogen requirement pressures from the first fuel cell and the second fuel cell, The control device is The system switches to supplying hydrogen from the hydrogen storage alloy tank to the fuel cells with the highest hydrogen demand pressure first. The hydrogen utilization system according to claim 1.

5. A control method for controlling the supply of hydrogen to a first fuel cell connected to a hydrogen storage alloy tank and generating electricity using hydrogen supplied from the hydrogen storage alloy tank, and a second fuel cell having a lower hydrogen demand pressure than the first fuel cell, wherein the control method switches the fuel cell from which hydrogen is supplied from the hydrogen storage alloy tank based on the hydrogen pressure in the hydrogen storage alloy tank. Control method.

Images