Cogeneration system
The cogeneration system addresses power outage issues by integrating a fuel cell module, storage tank, and control unit to manage heat transfer and power distribution, enabling continuous power generation through alternative pathways and heat consumption.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- TOKYO GAS CO LTD
- Filing Date
- 2022-12-20
- Publication Date
- 2026-05-12
AI Technical Summary
Cogeneration systems face challenges in continuing power generation during a power outage due to interruptions in the supply of a heat transfer medium, which can hinder their function as a backup power source.
The system incorporates a fuel cell module, a hot water storage tank, a heat exchanger, and a control unit that manages power distribution and heat transfer medium management to ensure continuous power generation by switching to alternative power paths and consuming heat during outages.
Enables the cogeneration system to maintain power generation even during power outages by managing heat transfer medium supply interruptions and utilizing backup power paths, ensuring reliable operation.
Smart Images
Figure 0007857212000001 
Figure 0007857212000002 
Figure 0007857212000003
Abstract
Description
Technical Field
[0006]
[0001] The present invention relates to a cogeneration system.
Background Art
[0002] For example, Patent Document 1 discloses a cogeneration system that generates hot water by using waste heat generated by power generation of a fuel cell module. In such a cogeneration system, the waste heat generated by power generation is transferred to a first heat medium (for example, water), and heat exchange is performed between the first heat medium and a second heat medium (for example, another water) flowing through a different path from the first heat medium. Thereby, hot water is generated.
Prior Art Documents
Patent Documents
[0007] In view of these problems, the present invention aims to provide a cogeneration system that can continue generating electricity even if the supply of a heat transfer medium is interrupted during a power outage. [Means for solving the problem]
[0008] To solve the above problems, the cogeneration system of the present invention comprises a fuel cell module that generates electricity based on hydrogen and air, a hot water storage tank for storing a heat transfer medium, and a heat exchanger that performs heat exchange between exhaust gas discharged from the fuel cell module and the heat transfer medium sent from the hot water storage tank and returned to the hot water storage tank. It is located in a secondary flow path, which is different from the primary flow path that circulates the hot water storage tank and heat exchanger. A heat-consuming device that consumes heat from a heat transfer medium supplied from a hot water storage tank; a temperature sensor that detects the temperature of the heat transfer medium in the hot water storage tank; a discharge passage that allows the heat transfer medium in the hot water storage tank to be discharged to the outside; a supply passage that allows the heat transfer medium to be supplied to the hot water storage tank from the outside; a supply interruption detection unit that detects the occurrence of a supply interruption indicating a state in which the heat transfer medium cannot be supplied to the hot water storage tank through the supply passage; and a power outage detection unit that detects a power outage in the power grid. A group of switches that are electrically connected between the circuit breaker, which is located inside the distribution board and electrically connected to the power system, and the fuel cell module, It comprises a control unit and, The heat-consuming equipment is electrically connected to the switch group. The control unit, when the fuel cell module is generating power, If a power outage is detected, the switch group is controlled to supply the power generated by the fuel cell module to the heat-consuming equipment without going through the circuit breaker. If a power outage is detected, and no supply interruption is detected during the power outage, and the temperature of the heat transfer medium in the hot water storage tank reaches a predetermined temperature or higher, indicating that it is close to full capacity, a portion of the heat transfer medium in the hot water storage tank will be discharged through the discharge channel, and a heat transfer medium with a lower temperature than the discharged heat transfer medium will be supplied to the hot water storage tank through the supply channel. If a power outage is detected, and a supply interruption is detected during the power outage, and the temperature of the heat transfer medium in the hot water storage tank reaches a predetermined temperature or higher, the heat transfer medium will not be discharged through the discharge channel, and the heat transfer medium will be supplied from the hot water storage tank to the heat consuming equipment, and the heat of the heat transfer medium will be consumed by the heat consuming equipment.
[0009] To solve the above problems, the cogeneration system of the present invention comprises a fuel cell module that generates electricity based on hydrogen and air, a hot water storage tank for storing a heat transfer medium, a heat exchanger that performs heat exchange between exhaust gas discharged from the fuel cell module and a heat transfer medium sent from the hot water storage tank and returned to the hot water storage tank, a heat consuming device that consumes the heat of the heat transfer medium when the heat transfer medium is supplied from the hot water storage tank, a temperature sensor that detects the temperature of the heat transfer medium in the hot water storage tank, a discharge passage that can discharge the heat transfer medium in the hot water storage tank to the outside, a supply passage that can supply the heat transfer medium to the hot water storage tank from the outside, and a supply passage The system includes a supply interruption detection unit that detects the occurrence of a supply interruption indicating a state in which a heat transfer medium cannot be supplied to the hot water storage tank, a power outage detection unit that detects a power outage in the power system, a group of switches electrically connected between a circuit breaker located in the distribution board and electrically connected to the power system and the fuel cell module, and a control unit, wherein the circuit breaker includes a first branch circuit breaker whose primary side end is electrically connected to the power system, and a second branch circuit breaker whose primary side end is electrically connected to the power system and is also electrically connected to the primary side end of the first branch circuit breaker, and the group of switches includes a first contact, a second contact, a third contact and A first changeover switch having a first contact and a second contact that can switch between a state in which the first contact and the second contact are electrically connected and a state in which the first contact and the third contact are electrically connected; a first interconnection relay having a first contact of the first changeover switch and a fuel cell module that can switch the electrical on / off state between the first contact of the first changeover switch and the secondary side end of the first branch breaker; a fourth contact, a fifth contact, and a sixth contact having a fourth contact and a fifth contact that can switch between a state in which the fourth contact and the fifth contact are electrically connected and a state in which the fourth contact and the sixth contact are electrically connected The system includes a replaceable second changeover switch, the third contact of the first changeover switch and the fourth contact of the second changeover switch are electrically connected to each other and are also electrically connected to a heat-consuming device, the fifth contact of the second changeover switch is electrically connected to the secondary end of the second branch breaker, and the sixth contact of the second changeover switch is electrically connected to an outlet, and the control unit controls the first changeover switch so that the first contact and the second contact are electrically connected when the fuel cell module is generating power and no power outage is detected.The first and second interconnection relays are controlled to the ON state, and the second changeover switch is controlled so that the fourth and fifth contacts are electrically connected. If a power outage is detected, the second interconnection relay is controlled to the OFF state, the first interconnection relay is controlled to the ON state, the first changeover switch is controlled so that the first and third contacts are electrically connected, and the second changeover switch is controlled so that the fourth and sixth contacts are electrically connected. If a power outage is detected, and no supply interruption is detected during the power outage, and the temperature of the heat transfer medium in the hot water storage tank reaches a predetermined temperature or higher, a portion of the heat transfer medium in the hot water storage tank is discharged through the discharge channel, and a heat transfer medium with a lower temperature than the discharged heat transfer medium is supplied to the hot water storage tank through the supply channel. If a power outage is detected, and a supply interruption is detected during the power outage, and the temperature of the heat transfer medium in the hot water storage tank reaches a predetermined temperature or higher, the heat transfer medium is not discharged through the discharge channel, and the heat transfer medium is supplied from the hot water storage tank to the heat consuming equipment, and the heat of the heat transfer medium is consumed by the heat consuming equipment. [Effects of the Invention]
[0010] According to the present invention, it is possible to continue power generation even if the supply of the heat transfer medium is interrupted during a power outage. [Brief explanation of the drawing]
[0011] [Figure 1] Figure 1 is a schematic diagram of the cogeneration system of this embodiment. [Figure 2] Figure 2 illustrates the state of the switch group when a power outage in the power grid is detected. [Figure 3] Figure 3 is a flowchart illustrating the operation flow of the control unit. [Figure 4] Figure 4 is a flowchart illustrating the operation flow of the control unit. [Modes for carrying out the invention]
[0012] Preferred embodiments of the present invention will be described in detail below with reference to the attached drawings. The dimensions, materials, and other specific numerical values shown in these embodiments are merely illustrative to facilitate understanding of the invention and do not limit the present invention unless otherwise specified. In this specification and drawings, elements having substantially the same function and configuration are denoted by the same reference numerals to avoid redundant explanations, and elements not directly related to the present invention are omitted from the illustration.
[0013] Figure 1 is a schematic diagram of the cogeneration system 1 of this embodiment. In Figure 1, heat transfer paths are shown with thick solid lines, and electrical wiring is shown with solid lines thinner than the solid lines showing the heat transfer paths. Also, the dashed arrows in Figure 1 indicate signal transmission. The cogeneration system 1 of this embodiment includes a distribution board 10, a fuel cell unit 12, a heat exchanger 14, a hot water storage unit 16, and heat consumption equipment 18.
[0014] The distribution board 10 has a main breaker 20 and a plurality of branch breakers 22. The primary side of the main breaker 20 is electrically connected to the power system 24. The primary sides of the plurality of branch breakers 22 are connected to the secondary side of the main breaker 20. In FIG. 1, three branch breakers, namely a branch breaker 22a, a branch breaker 22b, and a branch breaker 22c, are shown as the plurality of branch breakers 22. Note that the number of branch breakers 22 is not limited to three, and may be two or four or more.
[0015] The branch breaker 22a is a branch breaker 22 for AC 200V. The branch breaker 22a is connected, for example, between two voltage lines of a single-phase three-wire system. The branch breaker 22b and the branch breaker 22c are branch breakers 22 for AC 100V. The branch breaker 22b and the branch breaker 22c are connected, for example, between one voltage line and the neutral line of a single-phase three-wire system. An electrical load device 26 is connected to the secondary side of the branch breaker 22c.
[0016] The fuel cell unit 12 has a fuel cell module 30, a water tank 32, a separator 34, a converter 36, an inverter 38, a switch group 40, a power failure detection unit 42, and a control unit 44.
[0017] The fuel cell module 30 is, for example, a solid polymer fuel cell (PEFC). Note that the fuel cell module 30 is not limited to a solid polymer fuel cell, and may be, for example, a fuel cell of other types such as a solid oxide fuel cell (SOFC), a phosphoric acid fuel cell (PAFC), or a molten carbonate fuel cell (MCFC).
[0018] The water tank 32 is a hollow container that stores water. The water tank 32 is connected to the fuel cell module 30. Water in the water tank 32 is supplied to the fuel cell module 30 by a pump (not shown).
[0019] The fuel cell module 30 generates electricity based on hydrogen and air. For example, a fuel such as city gas is supplied to the fuel cell module 30. The fuel cell module 30 reforms the supplied fuel with water to generate hydrogen. Also, air containing oxygen is supplied to the fuel cell module 30. The fuel cell module 30 causes a chemical reaction between the generated hydrogen and the supplied air (more specifically, oxygen) to generate electricity.
[0020] In the fuel cell module 30, exhaust gas is generated during power generation. The exhaust gas includes a part of the air supplied to the fuel cell module 30 and water (more specifically, water vapor) generated by the chemical reaction.
[0021] The exhaust port of the fuel cell module 30 is connected to the heat exchanger 14. The heat exchanger 14 is supplied with the exhaust gas discharged from the fuel cell module 30. Also, as will be described in detail later, the heat exchanger 14 is supplied with a heat medium sent from the hot water storage tank 70 of the hot water storage unit 16. The heat medium is, for example, water, but may be any fluid capable of transferring heat. The heat exchanger 14 performs heat exchange between the exhaust gas discharged from the fuel cell module 30 and the heat medium sent from the hot water storage tank. Thereby, the heat of the exhaust gas is transferred to the heat medium.
[0022] The separator 34 is connected to the heat exchanger 14. Here, the temperature of the exhaust gas discharged from the fuel cell module 30 decreases by heat exchange in the heat exchanger 14. Thereby, the water vapor in the exhaust gas is condensed in the heat exchanger 14 to become liquid water. The separator 34 separates the liquid water from the exhaust gas containing the condensed liquid water. The liquid water separated by the separator 34 is sent to the water tank 32. The exhaust gas from which the liquid water has been removed by the separator 34 is discharged outside the fuel cell unit 12.
[0023] The converter 36 is electrically connected to the fuel cell module 30. The converter 36 converts the DC voltage generated by the fuel cell module 30 into another DC voltage. The inverter 38 is electrically connected to the converter 36. The inverter 38 converts the DC voltage converted by the converter 36 into an AC voltage.
[0024] Under normal circumstances, when there is no power outage in the power grid 24, the converter 36 and inverter 38 are controlled so that the output voltage of the fuel cell unit 12, i.e., the output voltage of the inverter 38, is AC200V. On the other hand, when there is a power outage in the power grid 24, the converter 36 and inverter 38 are controlled so that the output voltage of the fuel cell unit 12, i.e., the output voltage of the inverter 38, is AC100V.
[0025] The switch group 40 is electrically interposed between the inverter 38 and the multiple branch breakers 22 of the distribution board 10. The switch group 40 includes a first interconnection relay 50, a second interconnection relay 52, a first changeover switch 54, and a second changeover switch 56.
[0026] The first interconnection relay 50 has a first contact 50a and a second contact 50b. The first interconnection relay 50 is capable of switching the electrical on and off between the first contact 50a and the second contact 50b. The second interconnection relay 52 has a first contact 52a and a second contact 52b. The second interconnection relay 52 is capable of switching the electrical on and off between the first contact 52a and the second contact 52b.
[0027] The first changeover switch 54 has a first contact 54a, a second contact 54b, and a third contact 54c. The first changeover switch 54 can switch between a state in which the first contact 54a and the second contact 54b are electrically connected and a state in which the first contact 54a and the third contact 54c are electrically connected.
[0028] The second changeover switch 56 has a first contact 56a, a second contact 56b, and a third contact 56c. The second changeover switch 56 can switch between a state in which the first contact 56a and the second contact 56b are electrically connected and a state in which the first contact 56a and the third contact 56c are electrically connected.
[0029] The first contact 50a of the first interconnection relay 50 is connected to the inverter 38. The second contact 50b of the first interconnection relay 50 is connected to the first contact 54a of the first changeover switch 54.
[0030] The first contact 52a of the second interconnection relay 52 is connected to the second contact 54b of the first changeover switch 54. The second contact 52b of the second interconnection relay 52 is connected to the secondary side of the AC200V branch breaker 22a.
[0031] The first interconnection relay 50 and the second interconnection relay 52 are connected in series via the first changeover switch 54 and are electrically interposed between the fuel cell module 30 and the power grid 24.
[0032] The third contact 54c of the first changeover switch 54 is connected to the first contact 56a of the second changeover switch 56. The second contact 56b of the second changeover switch 56 is connected to the secondary side of the AC100V branch breaker 22b.
[0033] The hot water storage unit 16 and the heat consuming equipment 18 are electrically connected to the switch group 40. Specifically, the hot water storage unit 16 and the heat consuming equipment 18 are connected to the third contact 54c of the first changeover switch 54 and the first contact 56a of the second changeover switch 56. As will be described later, this connection allows switching between an electrical path in which the power of the fuel cell module 30 is supplied to the hot water storage unit 16 and the heat consuming equipment 18 via the distribution board 10, and an electrical path in which the power of the fuel cell module 30 is supplied to the hot water storage unit 16 and the heat consuming equipment 18 without going through the distribution board 10.
[0034] The third contact 56c of the second changeover switch 56 is connected to the outlet 60. The outlet 60 is a dedicated outlet for use during power outages, and is installed, for example, indoors. When an electrical load device is connected to the outlet 60 during a power outage, power can be supplied to the load device during the power outage.
[0035] The power outage detection unit 42 detects power outages in the power system 24. For example, the power outage detection unit 42 continuously monitors the power supplied from the power system 24 to the main circuit breaker 20. The power outage detection unit 42 detects that a power outage has occurred when the power on the primary side of the main circuit breaker 20 falls below a preset lower limit. The power outage detection unit 42 may also be configured to detect power outages by receiving information from the power company or the like that an outage will be caused.
[0036] The control unit 44 consists of a semiconductor integrated circuit including a processor, a ROM containing programs, and a RAM as a work area. The control unit 44 controls various parts of the fuel cell unit 12 by executing programs. In addition, the control unit 44 can indirectly control the hot water storage unit 16 and the heat consumption equipment 18 by communicating with them. The control unit 44 will be described in detail later.
[0037] The hot water storage unit 16 includes a hot water storage tank 70, a primary pump 72, a secondary pump 74, a temperature sensor 76, a discharge passage 78, a discharge valve 80, a discharge pump 82, a supply passage 84, a supply valve 86, a supply pump 88, and a supply interruption detection unit 90.
[0038] The hot water storage tank 70 is a hollow container that stores a heat transfer medium inside. The hot water storage tank 70 has a primary outlet 70a located vertically downward on its side and a primary inlet 70b located vertically upward on its side. The primary outlet 70a communicates with the heat exchanger 14 via a primary pump 72. The heat exchanger 14 communicates with the primary inlet 70b. The primary pump 72 sends the heat transfer medium from the hot water storage tank 70 to the heat exchanger 14 and returns the heat transfer medium to the hot water storage tank 70 through the heat exchanger 14.
[0039] As described above, the heat exchanger 14 performs heat exchange between the exhaust gas discharged from the fuel cell module 30 and the heat transfer medium sent from the hot water storage tank 70. The heat transfer medium, whose temperature has risen due to heat exchange in the heat exchanger 14, is sent to the hot water storage tank 70 through the primary side inlet 70b. In this way, the heat transfer medium in the hot water storage tank 70 circulates through the hot water storage tank 70, the primary pump 72, and the heat exchanger 14.
[0040] Furthermore, the hot water storage tank 70 is provided with a secondary outlet 70c located vertically upward on its side and a secondary inlet 70d located vertically downward on its side. The secondary outlet 70c is connected to the heat consuming equipment 18. The heat consuming equipment 18 is connected to the secondary inlet 70d of the hot water storage tank 70 via a secondary pump 74. The secondary pump 74 sends the heat transfer medium from the hot water storage tank 70 to the heat consuming equipment 18 and returns the heat transfer medium to the hot water storage tank 70 through the heat consuming equipment 18.
[0041] The heat-consuming device 18 is a device capable of consuming the heat from the heat transfer medium supplied from the hot water storage tank 70. The heat-consuming device 18 is, for example, a bathroom heater / dryer. However, the heat-consuming device 18 is not limited to a bathroom heater / dryer, but may be any device capable of consuming the heat from the heat transfer medium, such as a floor heating device.
[0042] The heat transfer medium sent from the hot water storage tank 70 to the heat consuming equipment 18 has its heat consumed in the heat consuming equipment 18. After the heat has been consumed in the heat consuming equipment 18, the heat transfer medium is returned to the hot water storage tank 70 through the secondary pump 74. In this way, the heat transfer medium in the hot water storage tank 70 circulates through the hot water storage tank 70, the heat consuming equipment 18, and the secondary pump 74.
[0043] The hot water storage tank 70 is equipped with a temperature sensor 76. The temperature sensor 76 detects the temperature of the heat transfer medium inside the hot water storage tank 70. The temperature sensor 76 is, for example, a thermistor. Multiple temperature sensors 76 may be distributed in the depth direction of the hot water storage tank 70. In this case, whether the hot water storage tank 70 is full may be determined based on the temperature of the heat transfer medium detected by the lowest temperature sensor 76 among the multiple temperature sensors 76 in the depth direction of the hot water storage tank 70.
[0044] The discharge channel 78 is connected to the vertical upper part of the hot water storage tank 70. The discharge channel 78 is a flow path that allows the heat transfer medium in the hot water storage tank 70 to be discharged to the outside. The discharge channel 78 is equipped with a discharge valve 80 and a discharge pump 82. The discharge valve 80 opens and closes the discharge channel 78. When the discharge valve 80 is open, the discharge pump 82 discharges the heat transfer medium in the hot water storage tank 70 to the outside through the discharge channel 78. The destination of the heat transfer medium may be, for example, a bathtub or other equipment that uses the heat transfer medium. Also, if the heat transfer medium is not needed, the destination of the heat transfer medium may be the sewer.
[0045] The temperature of the heat transfer medium in the hot water storage tank 70 increases with relative vertical elevation. Therefore, the heat transfer medium with the higher temperature is discharged through the discharge passage 78.
[0046] Furthermore, the supply passage 84 is connected to the vertical lower part of the hot water storage tank 70. The supply passage 84 is a passage through which a heat transfer medium can be supplied to the hot water storage tank 70 from the outside. The supply passage 84 is equipped with a supply valve 86 and a supply pump 88. The supply valve 86 opens and closes the supply passage 84. The supply pump 88 supplies the heat transfer medium from the outside to the hot water storage tank 70 through the supply passage 84 when the supply valve 86 is open. The source of the heat transfer medium may be, for example, equipment capable of supplying a heat transfer medium such as a water storage tank. Alternatively, the source of the heat transfer medium may be the public water supply.
[0047] The temperature of the heat transfer medium supplied to the hot water storage tank 70 through the supply channel 84 is lower than the temperature of the heat transfer medium discharged through the discharge channel 78.
[0048] The supply interruption detection unit 90 detects an interruption in the supply of the heat transfer medium to the hot water storage tank 70. A supply interruption indicates a state in which the heat transfer medium cannot be supplied to the hot water storage tank 70 from the outside through the supply passage 84. If the heat transfer medium is water, a supply interruption means a water outage. For example, the supply interruption detection unit 90 continuously monitors the pressure of the heat transfer medium in the supply passage 84, and detects that a supply interruption has occurred if the pressure of the heat transfer medium in the supply passage 84 falls below a predetermined pressure. The control unit 44 acquires the detection result of the supply interruption detection unit 90.
[0049] Next, the operation of the control unit 44 will be explained. Under normal conditions when no power outage is detected in the power system 24, the control unit 44 controls the first interconnection relay 50 and the second interconnection relay 52 to the ON state, as shown in Figure 1. At the same time, the control unit 44 controls the first changeover switch 54 to a state where the first contact 54a and the second contact 54b are connected, and controls the second changeover switch 56 to a state where the first contact 56a and the second contact 56b are connected.
[0050] As a result, the power generated by the fuel cell module 30 is transmitted in the following order: first interconnection relay 50, first changeover switch 54, second interconnection relay 52, branch breaker 22a, branch breaker 22b, and second changeover switch 56, and then supplied from the second changeover switch 56 to the hot water storage unit 16 and the heat consuming equipment 18. The power supplied to the hot water storage unit 16 is used, for example, to operate the primary pump 72, secondary pump 74, discharge valve 80, discharge pump 82, supply valve 86, and supply pump 88.
[0051] Furthermore, under normal conditions, the first interconnection relay 50 and the second interconnection relay 52, which are connected in series, are electrically interposed between the fuel cell module 30 and the power system 24. In this state, for example, if it is necessary to electrically disconnect the fuel cell module 30 from the power system 24, the control unit 44 turns off the first interconnection relay 50 and the second interconnection relay 52. In this case, even if a malfunction occurs in the first interconnection relay 50 and it cannot be turned off, the fuel cell module 30 can be reliably disconnected from the power system 24 by turning off the second interconnection relay 52. Also, even if a malfunction occurs in the second interconnection relay 52 and it cannot be turned off, the fuel cell module 30 can be reliably disconnected from the power system 24 by turning off the first interconnection relay 50.
[0052] Figure 2 illustrates the state of the switch group 40 when a power outage in the power system 24 is detected. In Figure 2, components other than electrical wiring are omitted for clarity.
[0053] When the power outage detection unit 42 detects a power outage in the power system 24, the control unit 44 controls the first interconnection relay 50 and the second interconnection relay 52 to the OFF state in order to disconnect the fuel cell module 30 from the power system 24. As shown in Figure 2, the control unit 44 controls the first 2 Grid-connected relay 5 2 After recognizing that it has turned off, 1 Grid-connected relay 5 0 The control unit 44 controls the first changeover switch 54 to a state where the first contact 54a and the third contact 54c are connected, and controls the second changeover switch 56 to a state where the first contact 56a and the third contact 56c are connected.
[0054] In other words, if a power outage in the power grid 24 is detected, the control unit 44 controls the switch group 40 to supply the power generated by the fuel cell module 30 to the heat-consuming equipment 18 without going through the branch breaker 22.
[0055] As a result, even if the second interconnection relay 52 is turned off due to a power outage and the fuel cell module 30 is disconnected from the power grid, power from the fuel cell module 30 can be properly supplied to the hot water storage unit 16 and the heat consuming equipment 18 during the power outage.
[0056] Incidentally, while the fuel cell module 30 is generating electricity, if the heat-consuming equipment 18 is stopped, the temperature of the heat transfer medium in the hot water storage tank 70 rises as the fuel cell module 30 generates electricity. When the temperature of the heat transfer medium in the hot water storage tank 70 reaches the upper limit temperature indicating full capacity, the fuel cell module 30 stops generating electricity for safety reasons.
[0057] For example, if a power outage is detected in the power grid 24 and the hot water storage tank 70 becomes full, causing the fuel cell module 30 to stop generating power, the fuel cell module 30 will not be able to fully perform its function as a backup power source during a power outage.
[0058] Therefore, when the fuel cell module 30 is generating power, the control unit 44 detects a power outage, and during the power outage, if the temperature of the heat transfer medium in the hot water storage tank 70 rises above a predetermined temperature indicating that it is close to full capacity, the control unit 44 discharges a portion of the heat transfer medium in the hot water storage tank 70 through the discharge passage 78, and supplies a heat transfer medium with a lower temperature than the discharged heat transfer medium into the hot water storage tank 70 through the supply passage 84. The predetermined temperature is set to a temperature below the upper limit temperature indicating full capacity, and close to that upper limit temperature.
[0059] As a result, the heat transfer medium in the hot water storage tank 70 is replaced with a heat transfer medium at a lower temperature, causing the temperature of the heat transfer medium in the hot water storage tank 70 to decrease. Consequently, it is possible to prevent the hot water storage tank 70 from becoming full during a power outage, and to continue generating power with the fuel cell module 30.
[0060] However, during a power outage, the supply of the heat transfer medium may also be interrupted. When this interruption occurs, it becomes impossible to replace the heat transfer medium in the hot water storage tank 70, which can cause the hot water storage tank 70 to become full. When the hot water storage tank 70 becomes full, the power generation of the fuel cell module 30 will stop.
[0061] Therefore, in this embodiment, in addition to the conditions of detecting a power outage and the storage tank 70 being nearly full, the condition of whether or not a supply interruption has occurred is added to control the storage unit 16 and the heat consumption equipment 18.
[0062] More specifically, when the fuel cell module 30 is generating power, the control unit 44 detects a power outage, and during the power outage, no supply interruption is detected, and the temperature of the heat transfer medium in the hot water storage tank 70 reaches a predetermined temperature or higher, indicating that it is close to full capacity, it discharges a portion of the heat transfer medium in the hot water storage tank 70 through the discharge passage 78, and supplies a heat transfer medium with a lower temperature than the discharged heat transfer medium into the hot water storage tank 70 through the supply passage 84.
[0063] On the other hand, when the fuel cell module 30 is generating power, the control unit 44 detects a power outage, and during the power outage, it detects a supply interruption, and the temperature of the heat transfer medium in the hot water storage tank 70 reaches a predetermined temperature or higher, indicating that it is close to full capacity, it does not discharge the heat transfer medium through the discharge passage 78, but instead supplies the heat transfer medium from the hot water storage tank 70 to the heat consuming equipment 18, and the heat from the heat transfer medium is consumed by the heat consuming equipment 18.
[0064] Hereafter, for the sake of explanation, the conditions under which a power outage is detected while the fuel cell module 30 is generating power, a supply interruption is detected during the power outage, and the temperature of the heat transfer medium in the hot water storage tank 70 is above a predetermined temperature indicating that it is close to full capacity, may be referred to as the forced consumption condition.
[0065] For example, when the above-mentioned forced consumption conditions are met, the control unit 44 communicates with the heat-consuming device 18 and forces the heat-consuming device 18 into an ON state where it can operate. In the event of a power outage, as shown in Figure 2, power is supplied from the fuel cell module 30 to the heat-consuming device 18 without going through the branch breaker 22, so even in the event of a power outage, the heat-consuming device 18 can be reliably turned ON.
[0066] When the heat-consuming device 18 is turned on, the heat transfer medium inlet in the heat-consuming device 18 opens, and the heat transfer medium is supplied from the hot water storage tank 70. For example, if the heat-consuming device 18 is a bathroom heater / dryer, the heat-consuming device 18 exchanges heat between the supplied heat transfer medium and the air taken in from the bathroom, and blows the warm air generated by the heat exchange into the bathroom by the rotation of an internal fan.
[0067] In this way, by controlling the heat-consuming device 18 to be in the ON state, the heat from the heat transfer medium supplied from the hot water storage tank 70 to the heat-consuming device 18 can be consumed by the heat-consuming device 18. This suppresses the rise in the temperature of the heat transfer medium in the hot water storage tank 70. As a result, even if the supply of the heat transfer medium is interrupted during a power outage, the fuel cell module 30 can continue to generate power.
[0068] Furthermore, if the heat-consuming equipment 18 is stopped and a power outage occurs, even if the supply is interrupted, the control unit 44 may maintain the stop state of the heat-consuming equipment 18 as long as the temperature of the heat transfer medium in the hot water storage tank 70 remains below a predetermined temperature.
[0069] Figures 3 and 4 are flowcharts illustrating the operation flow of the control unit 44. "A" in Figure 3 corresponds to "A" in Figure 4. The control unit 44 repeatedly performs the series of processes shown in Figure 3 each time a predetermined interrupt timing occurs at predetermined time intervals. The predetermined time interval may be set to any time interval, such as 1 second. Note that the initial state of the discharge valve 80 and the supply valve 86 is assumed to be closed, and the initial state of the discharge pump 82 and the supply pump 88 is assumed to be stopped.
[0070] When a predetermined interrupt timing arrives, the control unit 44 determines whether the fuel cell module 30 is currently generating power (S10). If the fuel cell module 30 is not generating power (NO in S10), the control unit 44 terminates the series of processes.
[0071] If the fuel cell module 30 is generating power (YES in S10), the control unit 44 determines whether a power outage has been detected in the power system 24 by the power outage detection unit 42 (S11).
[0072] If the power outage detection unit 42 detects a power outage in the power system 24 (YES in S11), the control unit 44 determines whether the supply interruption detection unit 90 has detected a supply interruption (S11). If no supply interruption is detected (NO in S12), the control unit 44 proceeds to the process in step S13.
[0073] Furthermore, if the power outage detection unit 42 does not detect a power outage in the power system 24 (NO in S11), the control unit 44 proceeds to the process in step S13.
[0074] In step S13, the control unit 44 determines whether the temperature of the heat transfer medium in the hot water storage tank 70, as detected by the temperature sensor 76, is above a predetermined temperature (S13). The predetermined temperature is set to a temperature below the upper limit temperature indicating full capacity, and close to that upper limit temperature.
[0075] If the temperature of the heat transfer medium in the hot water storage tank 70 is above a predetermined temperature (YES in S13), the control unit 44 opens the discharge valve 80 (S14) and drives the discharge pump 82 (S15). The control unit 44 opens the supply valve 86 (S16) and drives the supply pump 88 (S17), ending the series of processes.
[0076] Thus, if no power outage is detected and the hot water storage tank 70 is nearly full, or if a power outage is detected but no supply interruption is detected and the hot water storage tank 70 is nearly full, the heat transfer medium in the hot water storage tank 70 is replaced.
[0077] Furthermore, if the temperature of the heat transfer medium in the hot water storage tank 70 is below a predetermined temperature (NO in S13), the control unit 44 determines whether the temperature of the heat transfer medium in the hot water storage tank 70 detected by the temperature sensor 76 is below a preset recovery temperature (S18). The recovery temperature is set to a temperature lower than the predetermined temperature in step S13.
[0078] If the temperature of the heat transfer medium in the hot water storage tank 70 is below the recovery temperature (YES in S18), the control unit 44 closes the discharge valve 80 (S19) and stops the discharge pump 82 (S20). The control unit 44 closes the supply valve 86 (S21) and stops the supply pump 88 (S22), ending the series of processes. In this case, it is presumed that the heat transfer medium in the hot water storage tank 70 has been sufficiently replaced, and therefore the replacement of the heat transfer medium is completed.
[0079] If the temperature of the heat transfer medium in the hot water storage tank 70 is above the recovery temperature (NO in S18), the control unit 44 terminates the series of processes. In this case, if the hot water storage tank 70 is not being replaced, the discharge valve 80, supply valve 86, discharge pump 82, and supply pump 88 are maintained in their initial state, and if the hot water storage tank 70 is being replaced, the replacement of the hot water storage tank 70 continues.
[0080] Furthermore, if a supply interruption is detected in step S12 (YES in S12), the process moves from "A" in Figure 3 to "A" in Figure 4, and the control unit 44 proceeds to the process in step S30 of Figure 4.
[0081] In step S30, the control unit 44 determines whether the temperature of the heat transfer medium in the hot water storage tank 70, as detected by the temperature sensor 76, is above a predetermined temperature (S30). The predetermined temperature here is the same as the predetermined temperature in step S13.
[0082] If the temperature of the heat transfer medium in the hot water storage tank 70 is above a predetermined temperature (YES in S30), the control unit 44 closes the discharge valve 80 (S31) and stops the discharge pump 82 (S32). The control unit 44 closes the supply valve 86 (S33) and stops the supply pump 88 (S34). The control unit 44 communicates with the heat consuming device 18 to force it to turn on and supplies the heat transfer medium from the hot water storage tank 70 to the heat consuming device 18 (S35), and ends the series of processes.
[0083] Thus, when a power outage is detected, a supply interruption is detected, and the hot water storage tank 70 is nearly full, the heat transfer medium in the hot water storage tank 70 is not replaced, and the heat transfer medium is supplied from the hot water storage tank 70 to the heat consuming equipment 18. As a result, the heat from the heat transfer medium supplied from the hot water storage tank 70 to the heat consuming equipment 18 is consumed by the heat consuming equipment 18.
[0084] Furthermore, if the temperature of the heat transfer medium in the hot water storage tank 70 is below a predetermined temperature (NO in S30), the control unit 44 determines whether the temperature of the heat transfer medium in the hot water storage tank 70 detected by the temperature sensor 76 is below the recovery temperature (S36). The recovery temperature here is the same as the recovery temperature in step S18.
[0085] If the temperature of the heat transfer medium in the hot water storage tank 70 is below the recovery temperature (YES in S36), the control unit 44 closes the discharge valve 80 (S37) and stops the discharge pump 82 (S38). The control unit 44 closes the supply valve 86 (S39) and stops the supply pump 88 (S40). The control unit 44 stops the supply of heat transfer medium from the hot water storage tank 70 to the heat consuming equipment 18 (S41), ending the series of processes. In step S41, the operation of the heat consuming equipment 18 may also be stopped. In this case, it is presumed that the heat of the heat transfer medium in the hot water storage tank 70 has been sufficiently consumed by the heat consuming equipment 18, and therefore the supply of heat transfer medium from the hot water storage tank 70 to the heat consuming equipment 18 is terminated.
[0086] If the temperature of the heat transfer medium in the hot water storage tank 70 is above the recovery temperature (NO in S36), the control unit 44 terminates the series of processes. In this case, if the heat transfer medium is not being supplied to the heat consuming equipment 18, the heat consuming equipment 18 remains stopped. If the heat transfer medium is being supplied to the heat consuming equipment 18, the heat consuming equipment 18 continues to consume heat from the heat transfer medium.
[0087] As described above, in the cogeneration system 1 of this embodiment, when the fuel cell module 30 is generating power, a power outage is detected, and during the power outage, no supply interruption is detected, and the temperature of the heat transfer medium in the hot water storage tank 70 reaches a predetermined temperature or higher, indicating that it is close to full capacity, the control unit 44 discharges a portion of the heat transfer medium in the hot water storage tank 70 through the discharge passage 78, and supplies a heat transfer medium with a lower temperature than the discharged heat transfer medium into the hot water storage tank 70 through the supply passage 84. Furthermore, in the cogeneration system 1 of this embodiment, when the fuel cell module 30 is generating power, a power outage is detected, and during the power outage, a supply interruption is detected, and the temperature of the heat transfer medium in the hot water storage tank 70 reaches a predetermined temperature or higher, the control unit 44 does not discharge the heat transfer medium through the discharge passage 78, but instead supplies the heat transfer medium from the hot water storage tank 70 to the heat consuming equipment 18, and the heat of the heat transfer medium is consumed by the heat consuming equipment 18.
[0088] As a result, in the cogeneration system 1 of this embodiment, even if the supply of the heat transfer medium is interrupted during a power outage in the power grid 24, it is possible to prevent the temperature of the heat transfer medium in the hot water storage tank 70 from reaching its maximum level.
[0089] Therefore, according to the cogeneration system 1 of this embodiment, it is possible to continue power generation even if the supply of the heat transfer medium is interrupted during a power outage.
[0090] Furthermore, in the case of a power outage, the control unit 44 of the cogeneration system 1 of this embodiment controls the switch group 40 to supply the power generated by the fuel cell module 30 to the heat consuming equipment 18 without going through the branch breaker 22.
[0091] As a result, in the cogeneration system 1 of this embodiment, power can be properly supplied from the fuel cell module 30 to the hot water storage unit 16 and the heat consuming equipment 18 during a power outage in the power grid 24. Consequently, even if a power outage is detected, the heat transfer medium in the hot water storage tank 70 can be reliably supplied to the heat consuming equipment 18.
[0092] Preferred embodiments of the present invention have been described above with reference to the attached drawings, but it goes without saying that the present invention is not limited to these embodiments. It is clear to those skilled in the art that various modifications or alterations can be conceived within the scope of the claims, and these will naturally also fall within the technical scope of the present invention.
[0093] For example, in the above embodiment, when a power outage and supply interruption were detected and the hot water storage tank was nearly full, the heat from the heat transfer medium in the hot water storage tank was consumed by the heat-consuming equipment. However, it is also possible to consume the heat from the heat transfer medium in the hot water storage tank by the heat-consuming equipment when a power outage is detected and the hot water storage tank is nearly full, regardless of whether or not there is a supply interruption. Furthermore, it is possible to select whether to prioritize consuming the heat from the heat transfer medium in the hot water storage tank by the heat-consuming equipment or replacing the heat transfer medium in the hot water storage tank when a power outage is detected and the hot water storage tank is nearly full. [Explanation of Symbols]
[0094] 1. Cogeneration System 10-minute distribution board 14 Heat exchanger 18 Heat consuming equipment 22 Branch circuit breakers 24 Power system 30 Fuel Cell Modules 40 switch group 42 Power outage detection unit 44 Control Unit 70 Hot water storage tank 76 Temperature Sensor 78 Exhaust channel 84 Supply route 90 Supply interruption detection unit
Claims
1. A fuel cell module that generates electricity based on hydrogen and air, A hot water storage tank for storing the heat transfer medium, A heat exchanger that performs heat exchange between exhaust gas discharged from the fuel cell module and the heat transfer medium sent from the hot water storage tank and returned to the hot water storage tank, A heat-consuming device is provided in a secondary flow path different from the primary flow path that circulates the hot water storage tank and the heat exchanger, and consumes the heat of the heat transfer medium by being supplied with the heat transfer medium from the hot water storage tank. A temperature sensor for detecting the temperature of the heat transfer medium in the hot water storage tank, A discharge passage that allows the heat transfer medium in the hot water storage tank to be discharged to the outside, The hot water storage tank includes a supply path that allows the heat transfer medium to be supplied from the outside, A supply interruption detection unit detects the occurrence of a supply interruption, which indicates a state in which the heat transfer medium cannot be supplied to the hot water storage tank through the supply path. A power outage detection unit that detects power outages in the power grid, A group of switches, which are electrically connected between a circuit breaker located inside the distribution board and electrically connected to the power system and the fuel cell module, Control unit and Equipped with, The heat-consuming equipment is electrically connected to the switch group, The control unit, While the fuel cell module is generating power, If the aforementioned power outage is detected, the switch group is controlled to supply the power generated by the fuel cell module to the heat-consuming equipment without going through the circuit breaker. If the aforementioned power outage is detected, and no supply interruption is detected during the power outage, and the temperature of the heat transfer medium in the hot water storage tank reaches a predetermined temperature or higher, indicating that it is close to full capacity, a portion of the heat transfer medium in the hot water storage tank is discharged through the discharge passage, and a portion of the heat transfer medium with a lower temperature than the discharged portion is supplied into the hot water storage tank through the supply passage. A cogeneration system in which, when the aforementioned power outage is detected, and during the power outage, the occurrence of the supply interruption is detected, and the temperature of the heat transfer medium in the hot water storage tank rises to or above the predetermined temperature, the heat transfer medium is not discharged through the discharge passage, and the heat transfer medium is supplied from the hot water storage tank to the heat consuming equipment, and the heat of the heat transfer medium is consumed by the heat consuming equipment.
2. A fuel cell module that generates electricity based on hydrogen and air, A hot water storage tank for storing the heat transfer medium, A heat exchanger that performs heat exchange between exhaust gas discharged from the fuel cell module and the heat transfer medium sent from the hot water storage tank and returned to the hot water storage tank, The heat transfer medium is supplied from the hot water storage tank, and a heat consuming device consumes the heat of the heat transfer medium. A temperature sensor for detecting the temperature of the heat transfer medium in the hot water storage tank, A discharge passage that allows the heat transfer medium in the hot water storage tank to be discharged to the outside, The hot water storage tank includes a supply path that allows the heat transfer medium to be supplied from the outside, A supply interruption detection unit detects the occurrence of a supply interruption, which indicates a state in which the heat transfer medium cannot be supplied to the hot water storage tank through the supply path. A power outage detection unit that detects power outages in the power grid, A group of switches, which are electrically connected between a circuit breaker located inside the distribution board and electrically connected to the power system and the fuel cell module, Control unit and Equipped with, The circuit breaker includes a first branch circuit breaker whose primary side end is electrically connected to the power system, and a second branch circuit breaker whose primary side end is electrically connected to the power system and is also electrically connected to the primary side end of the first branch circuit breaker. The aforementioned group of switches, A first changeover switch having a first contact, a second contact, and a third contact, which can switch between a state in which the first contact and the second contact are electrically connected and a state in which the first contact and the third contact are electrically connected. A first interconnection relay capable of switching the electrical on / off state between the first contact of the first changeover switch and the fuel cell module, A second interconnection relay capable of switching the electrical on / off state between the second contact of the first changeover switch and the secondary side end of the first branch breaker, A second changeover switch having a fourth contact, a fifth contact, and a sixth contact, which can switch between a state in which the fourth contact and the fifth contact are electrically connected and a state in which the fourth contact and the sixth contact are electrically connected. It has, The third contact of the first changeover switch and the fourth contact of the second changeover switch are electrically connected to each other and are also electrically connected to the heat-consuming equipment. The fifth contact of the second changeover switch is electrically connected to the secondary side end of the second branch breaker. The sixth contact of the second changeover switch is electrically connected to the outlet. The control unit, While the fuel cell module is generating power, If no power outage is detected, the first changeover switch is controlled so that the first contact and the second contact are electrically connected, the first interconnection relay and the second interconnection relay are controlled to the ON state, and the second changeover switch is controlled so that the fourth contact and the fifth contact are electrically connected. If the aforementioned power outage is detected, the second interconnection relay is controlled to the OFF state, the first interconnection relay is controlled to the ON state, the first changeover switch is controlled so that the first contact and the third contact are electrically connected, and the second changeover switch is controlled so that the fourth contact and the sixth contact are electrically connected. If the aforementioned power outage is detected, and no supply interruption is detected during the power outage, and the temperature of the heat transfer medium in the hot water storage tank reaches a predetermined temperature or higher, indicating that it is close to full capacity, a portion of the heat transfer medium in the hot water storage tank is discharged through the discharge passage, and a portion of the heat transfer medium with a lower temperature than the discharged portion is supplied into the hot water storage tank through the supply passage. A cogeneration system in which, when the aforementioned power outage is detected, and during the power outage, the occurrence of the supply interruption is detected, and the temperature of the heat transfer medium in the hot water storage tank rises to or above the predetermined temperature, the heat transfer medium is not discharged through the discharge passage, and the heat transfer medium is supplied from the hot water storage tank to the heat consuming equipment, and the heat of the heat transfer medium is consumed by the heat consuming equipment.