JP-7857212-B2 - Cogeneration system

JP7857212B2JP 7857212 B2JP7857212 B2JP 7857212B2JP-7857212-B2

Inventors

高須俊樹
本道正樹
伊藤裕介
伴野卓也
大村俊哉

Assignees

東京瓦斯株式会社

Dates

Publication Date: 20260512
Application Date: 20221220

Claims (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, 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 when the heat transfer medium is supplied 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.
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.

Description

This invention relates to a cogeneration system. For example, Patent Document 1 discloses a cogeneration system that generates hot water using waste heat generated by a fuel cell module. In such a cogeneration system, waste heat generated by power generation is transferred to a first heat transfer medium (for example, water), and hot water is generated by heat exchange between the first heat transfer medium and a second heat transfer medium (for example, other water) that flows through a different path from the first heat transfer medium. Japanese Patent Publication No. 2014-191949 Figure 1 is a schematic diagram of the cogeneration system of this embodiment.Figure 2 illustrates the state of the switch group when a power outage in the power grid is detected.Figure 3 is a flowchart illustrating the operation flow of the control unit.Figure 4 is a flowchart illustrating the operation flow of the control unit. 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, unless otherwise specified, do not limit the present invention. In this specification and the 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 illustrations. 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 thinner solid lines than the solid lines showing the heat transfer paths. 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. The distribution board 10 has a main circuit breaker 20 and multiple branch circuit breakers 22. The primary side of the main circuit breaker 20 is electrically connected to the power system 24. The primary sides of the multiple branch circuit breakers 22 are connected to the secondary side of the main circuit breaker 20. In Figure 1, three branch circuit breakers 22a, branch circuit breaker 22b, and branch circuit breaker 22c are shown as the multiple branch circuit breakers 22. Note that the number of branch circuit breakers 22 is not limited to three; it may be two, four or more. Branch breaker 22a is a branch breaker 22 for AC 200V. Branch breaker 22a is connected, for example, between two voltage lines in a single-phase three-wire system. Branch breakers 22b and 22c are branch breakers 22 for AC 100V. Branch breakers 22b and 22c are connected, for example, between one voltage line and the neutral line in a single-phase three-wire system. An electrical load device 26 is connected to the secondary side of branch breaker 22c. The fuel cell unit 12 includes 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. The fuel cell module 30 is, for example, a polymer electrolyte fuel cell (PEFC). However, the fuel cell module 30 is not limited to polymer electrolyte fuel cells; it may also be other types of fuel cells, such as solid oxide fuel cells (SOFCs), phosphoric acid fuel cells (PAFCs), or molten carbonate fuel cells (MCFCs). The water tank 32 is a hollow container that stores water. The water tank 32 is connected to the fuel cell module 30. Water from the water tank 32 is supplied to the fuel cell module 30 by a pump (not shown). The fuel cell module 30 generates electricity based on hydrogen and air. For example, the fuel cell module 30 is supplied with fuel such as city gas. The fuel cell module 30 produces hydrogen by reforming the supplied fuel and water. The fuel cell module 30 is also supplied with air containing oxygen. The fuel cell module 30 generates electricity (electricity generation) by chemically reacting the generated hydrogen with the supplied air (more specifically, oxygen). The fuel cell module 30 generates exhaust gas during power generation. This exhaust gas contains a portion of the air supplied to the fuel cell module 30, and water (more specifically, water vapor) produced by the chemical reaction. The exhaust port of the fuel cell module 30 is connected to the heat exchanger 14. The heat exchanger 14 is supplied with exhaust gas discharged from the fuel cell module 30. Furthermore, as will be described in detail later, the heat exchanger 14 is supplied with a heat transfer medium sent from the hot water storage tank 70 of the hot water storage unit 16. The heat transfer medium is, for example, water, but any fluid capable of transferring heat may be used. The hea