JP2013069598A - Cogeneration system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cogeneration system which can be operated continuously without disabling the safety interruption function of a microcomputer meter, and can be operated with high energy efficiency while stabilizing the amount of power generation by a fuel cell.SOLUTION: In the cogeneration system having a power generation section incorporating a fuel cell and generating electrical energy and thermal energy simultaneously, and heating hot water by heat generated in the power generation section, a storage tank for storing hot water, an auxiliary heat source for heating hot water as required, a storage system for supplying the hot water heated in the auxiliary heat source to the storage tank, and a fuel supply system for supplying fuel gas to the power generation section and the auxiliary heat source are provided. On condition that power generation by the power generation section has sustained for a predetermined time or longer, fuel gas consumption operation is carried out forcibly. In the fuel gas consumption operation, hot water heated by combustion operation of the auxiliary heat source is stored in the storage tank.

Description

  The present invention relates to a cogeneration system using a fuel cell.

  2. Description of the Related Art Conventionally, a cogeneration system that generates electric power and can use exhaust heat generated at that time for hot water supply or heating is known. And as a power generation means employ | adopted for this kind of system, there exist a thing by a gas engine and a thing by a fuel cell. As the fuel cell, a polymer electrolyte fuel cell (hereinafter also referred to as PEFC) and a solid oxide fuel cell (hereinafter also referred to as SOFC) are known.

  The cogeneration system generates power by introducing fuel gas, not only by a gas engine but also by a fuel cell. Specifically, in a fuel cell cogeneration system, a gas rich in hydrogen is generated by a reformer from gas such as city gas, LPG, digestion gas, methanol, GTL (Gas to Liquid), and generated. Power is generated by an electrochemical reaction between the hydrogen-rich gas and an oxygen-containing oxidant gas. And when using such a cogeneration system in a general household, commercial gas, such as city gas and LPG, is adopted as gas from a viewpoint of availability.

  By the way, when receiving commercial gas supply in a general household, from the viewpoint of safety, if the gas flow rate does not change greatly, it continues to flow for a certain period of time, and the gas is passed through a meter that has a function of blocking the gas flow. May be supplied. A meter having such a function is generally called a microcomputer meter. The microcomputer meter is a function that shuts off the gas flow for safety when the gas supply is dangerous, such as when the rubber tube is removed or when the bath is left open. It is a meter with a cutoff function. Therefore, the microcomputer meter automatically shuts off the gas supply when the above-described situation is predicted, specifically, when it continues to flow for a certain period of time without a large change in the gas flow rate.

  From the above, when a cogeneration system using a fuel cell is used in a general household, the gas usually passes through a microcomputer meter in many cases.

  Here, the cogeneration system (especially SOFC) using a fuel cell is generally used for a long time without being stopped immediately after being once started. More specifically, in a fuel cell cogeneration system (especially SOFC), when the fuel cell stops operation, it cannot be restarted unless the temperature drops below a certain value, so that it cannot be started, stopped, or restarted in a short time. Therefore, a cogeneration system using a fuel cell is operated without being stopped for a long time once activated.

  However, when a cogeneration system using a fuel cell is used without being stopped for a long time, the commercial gas supplied to the fuel cell may flow without changing its flow rate for a certain time or more. Then, even if it was a normal operation | movement, the microcomputer meter misidentified that there was gas leak, and there existed a possibility of interrupting | blocking the flow of gas. That is, there is a possibility that the gas supply to the fuel cell is cut off by the microcomputer meter and the cogeneration system is stopped.

As a technique for avoiding the stop of the cogeneration system due to such misidentification of the microcomputer meter, there is a technique disclosed in Patent Document 1, for example. In the fuel cell system of Patent Document 1, when the fluctuation of the flow rate of the commercial gas passing through the meter within a predetermined time is within a predetermined width, the flow rate of the commercial gas passing through the meter is changed by changing the output of the fuel cell. The above is fluctuating.
That is, the malfunction of the microcomputer meter is prevented by forcibly changing the amount of gas supplied to the fuel cell.

Japanese Patent No. 4399553

  However, the method of forcibly changing the amount of gas supplied to the fuel cell is not preferable from the viewpoint of stabilizing the power generation amount of the cogeneration system. That is, in order to change the gas supply amount, it is a problem that it is not desirable in operating the cogeneration system to perform an unnecessary amount of power generation or not to generate a necessary amount of power generation.

  Therefore, a configuration is conceivable in which the gas supplied to prevent the malfunction of the microcomputer meter is supplied to other equipment such as a combustion device without being supplied to the fuel cell. For example, a method is conceivable in which a combustion operation is performed by a combustion device using a gas supplied to prevent malfunction of a microcomputer meter, and heating equipment is heated to dissipate heat.

  However, even such a method has a problem that it is not desirable from the viewpoint of energy efficiency because the heating device is unnecessarily heated.

  Therefore, in view of the above-described problems, the present invention is capable of continuous operation without invalidating the safety shut-off function of the microcomputer meter, and is capable of operating with high energy efficiency while stabilizing the amount of power generated by the fuel cell. The problem is to provide a system.

  The invention according to claim 1 for solving the above-described problem has a power generation unit that has a built-in fuel cell and generates electric energy and thermal energy at the same time, and hot water is generated by the heat generated by the power generation unit. In a heating cogeneration system, a storage tank for storing hot water, an auxiliary heat source part for heating hot water as required, a storage system for supplying hot water heated by the auxiliary heat source part to the storage tank, and the power generation part And a fuel supply system for supplying fuel gas to the auxiliary heat source section, and forcibly performing the fuel gas consumption operation on condition that power generation by the power generation section has continued for a predetermined time or more. The consumption operation is a cogeneration system characterized in that hot water heated by the combustion operation of the auxiliary heat source unit is stored in a storage tank.

In the cogeneration system of the present invention, the fuel gas consumption operation by the auxiliary heat source unit is forcibly performed on condition that the power generation by the power generation unit has continued for a predetermined time or more. That is, when the operation of the cogeneration system is continued and the fuel gas is continuously supplied to the fuel cell, the flow rate of the gas is forcibly changed as the predetermined time or more elapses. Therefore, unlike the case of gas leakage, the gas flow rate is not constant, so during normal operation of the cogeneration system, a safety shut-off function by a device such as a microcomputer meter (the fuel gas supply is shut off for safety) Function) does not work. This allows continuous operation without invalidating the safety shut-off function of the microcomputer meter.
In the cogeneration system of the present invention, when the gas flow rate is forcibly changed, the fuel gas consumption operation is performed by the auxiliary heat source unit. That is, when the gas supply amount is increased in order to forcibly change the gas flow rate, the increased amount of gas is supplied to the auxiliary heat source unit instead of the fuel cell. That is, the flow rate of the gas supplied to the fuel cell is the same as that before the gas flow rate is forcibly changed. In other words, in the present invention, the power generation amount of the fuel cell is not changed in order to avoid the operation of the safety shut-off function by a device such as a microcomputer meter. As a result, the power generation amount of the fuel cell does not need to be changed unnecessarily, so that the operation of the fuel cell can be stabilized.
Furthermore, in the cogeneration system of the present invention, hot water heated by the combustion operation of the auxiliary heat source section is stored in the storage tank in the fuel gas consumption operation in which the gas flow rate is forcibly changed. In other words, when the gas supply amount is increased in order to forcibly change the gas flow rate, heat energy is generated by the increased gas, and the generated heat energy is accumulated. Therefore, the gas to be supplied in order to avoid the safety shut-off function by a device such as a microcomputer meter is not wasted and energy efficiency is good.

  In the cogeneration system of the present invention, the fuel supply system is provided with a supply shut-off means capable of shutting off the supply of fuel gas, and when the supply shut-off means continues to use a constant gas flow rate, The fuel gas supply is preferably cut off (claim 2).

  The cogeneration system of the present invention may include a gas pipe drawn into a house or the like, and a device having a function of blocking gas supply for safety provided therein. Even with such a configuration, it is possible to operate continuously without invalidating the safety shut-off function, and it is possible to operate with high energy efficiency while stabilizing the amount of power generated by the fuel cell.

  According to a third aspect of the present invention, the power generation time by the power generation unit is integrated, and based on the integrated result, it is determined whether the power generation by the power generation unit has continued for a predetermined time. If the auxiliary heat source unit is in the combustion operation before the implementation, the initial value of the power generation time is initialized on the condition that a certain amount or more of the gas has been consumed or calculated by the operation. The cogeneration system according to claim 1 or 2, characterized in that:

  In the cogeneration system of the present invention, the power generation time by the power generation unit is integrated, and based on the integrated result, it is determined whether or not the power generation by the power generation unit has continued for a predetermined time. If it is confirmed that a certain amount or more of gas has been consumed by the combustion operation of the auxiliary heat source unit before the fuel gas consumption operation is performed, the integrated value of the power generation time is initialized. This makes it possible to operate an efficient cogeneration system without unnecessarily increasing the number of fuel gas consuming operations. This will be specifically described below.

  As described above, in the safety shut-off function by a device such as a microcomputer meter, the gas supply is shut off when the gas flow rate does not change greatly and continues for a predetermined time. That is, a device such as a microcomputer meter measures the time during which the gas continues to flow in a state where there is no significant change in the flow rate (hereinafter also referred to as a gas supply duration). Here, when a certain amount or more of gas is consumed by the combustion operation of the auxiliary heat source unit and the supply amount of the gas to the cogeneration system changes, a device such as a microcomputer meter detects that the gas flow rate has changed. A device such as a microcomputer meter discards the previous gas supply continuation time accumulated until the gas flow rate changes, and accumulates a new gas supply continuation time from the time when the gas flow rate changes.

  Therefore, before the cogeneration system performs the fuel gas consumption operation, if the combustion operation by the auxiliary heat source machine is performed for some reason and the gas flow rate changes, the gas supply duration time measured by devices such as a microcomputer meter is In addition, the auxiliary heat source device is newly measured from the time when the combustion operation is performed.

  Here, the fuel cell of the cogeneration system continues to generate power before and after the auxiliary heat source unit performs the combustion operation. Therefore, in the cogeneration system, if the fuel gas consumption operation is simply performed on condition that power generation has continued for a predetermined time or more, even though there is sufficient time until the gas supply is cut off by a device such as a microcomputer meter, There is a risk that fuel gas consuming operation will be carried out. Specifically, the gas supply duration measured by a device such as a microcomputer meter is measured from the time when the auxiliary heat source unit performs the combustion operation, whereas the integrated value of the power generation time of the cogeneration system is the auxiliary heat source. It is measured before the machine performs the combustion operation. For this reason, in a situation where there is sufficient time until the gas supply duration exceeds the predetermined time, the integrated value of the power generation time may be equal to or longer than the predetermined time. In such a case, the cogeneration system performs the fuel gas consumption operation even though there is sufficient time until the gas supply is cut off by a device such as a microcomputer meter.

  As described above, when the fuel gas consuming operation for avoiding the shutoff of the gas supply is performed under the situation where there is a sufficient time until the gas supply is interrupted after the gas supply duration exceeds the predetermined time. When the cogeneration system is operated, the number of fuel gas consumption operations is unnecessarily increased, and the operation efficiency of the cogeneration system is deteriorated.

  Here, in the present invention, the integrated value of the power generation time is initialized when it is confirmed that a certain amount or more of gas has been consumed by the combustion operation of the auxiliary heat source unit. According to such a configuration, the integration of the duration of power generation by the fuel cell can be started together with the start of integration of a new gas supply duration by a device such as a microcomputer meter. As a result, the fuel gas consuming operation is not performed even though there is sufficient time until the gas supply is cut off. That is, the fuel gas consumption operation can be performed at an appropriate time in the time from the start of integration of the gas supply duration time until the predetermined time elapses. This makes it possible to operate an efficient cogeneration system that performs the fuel gas consumption operation only in a truly necessary situation.

  The invention according to claim 4 is capable of performing an operation of storing hot water having a target hot water storage set temperature in a storage tank, and at the start of the fuel gas consumption operation, a predetermined portion of hot water in the storage tank. The cogeneration system according to any one of claims 1 to 3, wherein when the temperature is equal to or higher than a hot water storage set temperature and the hot water storage tank is filled with hot water, the hot water storage set temperature is changed upward. is there.

  In the cogeneration system of the present invention, the hot water set temperature is changed upward when hot water of the hot water set temperature or higher is filled in the storage tank. For this reason, even if it is a case where the inside of the storage tank is already filled with the hot water of hot water storage preset temperature, a fuel gas consumption driving | operation can be implemented.

  More specifically, in the cogeneration system, the hot water is circulated between the power generation unit and the storage tank, the power generation operation is performed, and the hot water heated by the thermal energy generated by the power generation flows into the storage tank. Perform a collection operation. In such a heat recovery operation, the hot water in the storage tank is caused to flow out and heated so that the hot water in the storage tank becomes the hot water set temperature, and then returned to the storage tank again. Such a heat recovery operation may be performed constantly while the cogeneration system is operated.

  By the way, when the fuel gas consumption operation is performed, the heated hot water flows into the storage tank, so that the temperature of the hot water in the storage tank rises. Here, in a situation where hot water of a hot water storage set temperature is already stored in the storage tank, if the fuel gas consumption operation is performed, the hot water in the storage tank may exceed the hot water storage set temperature due to the fuel gas consumption operation. Can be considered. As described above, if the hot water in the storage tank exceeds the preset hot water storage temperature due to the fuel gas consumption operation, the heat recovery operation that is always performed may not be performed correctly.

  Therefore, in the present invention, when the storage tank is filled with hot water of a hot water storage set temperature or higher, the hot water storage set temperature is changed upward. As a result, even if the temperature of the hot water in the storage tank rises due to the fuel gas consumption operation, the hot water in the storage tank does not exceed the hot water storage set temperature. That is, when the fuel gas consuming operation is performed in a situation where the storage tank is filled with hot water having a set temperature of hot water, the hot water set temperature is changed in advance, so that the temperature of the hot water in the storage tank by the fuel gas consuming operation Even if the temperature rises, it does not exceed the hot water storage set temperature changed upward. Therefore, operations such as heat recovery operation of the cogeneration system can be performed accurately.

  A fifth aspect of the present invention is the cogeneration system according to any one of the first to fourth aspects, wherein in the fuel gas consumption operation, the combustion operation of the auxiliary heat source unit is performed with a predetermined combustion amount. .

In the cogeneration system of the present invention, the combustion operation of the auxiliary heat source unit in the fuel gas consumption operation is performed with a predetermined combustion amount. Therefore, the amount of fuel gas used in the fuel gas consumption operation, that is, the amount of fuel gas used to avoid the operation of the safety shut-off function by a device such as a microcomputer meter can be suppressed. Therefore, the energy efficient operation of the cogeneration system is possible.
The predetermined combustion amount may be the minimum combustion amount, the combustion amount that minimizes the combustion noise, or may be a combustion amount that is larger than the minimum combustion amount for measures against wind resistance of exhaust gas.

  According to the present invention, the fuel gas consumption operation by the auxiliary heat source unit is forcibly performed on condition that the power generation by the power generation unit has continued for a predetermined time or longer. And drive. Further, since the fuel gas is not supplied to the fuel cell during the fuel gas consumption operation, the power generation amount of the fuel cell does not need to be changed unnecessarily, and the operation of the fuel cell can be stabilized. In addition, hot water is heated by the gas supplied for the fuel gas consumption operation, and the heated hot water is stored, so that the gas supplied for the fuel gas consumption operation is not wasted and energy efficient operation is possible. Become.

It is an operation principle figure showing a cogeneration system concerning an embodiment of the present invention. FIG. 2 is an operation principle diagram of the cogeneration system of FIG. 1, and shows a heat recovery path in black. FIG. 2 is an operation principle diagram of the cogeneration system of FIG. 1, and shows a hot water supply path in black. FIG. 2 is an operation principle diagram of the cogeneration system of FIG. 1, and shows a heat supply path in black. FIG. 2 is an operation principle diagram of the cogeneration system of FIG. 1, and is a diagram showing a storage path in black. It is a flowchart which shows the operation | movement procedure of the fuel gas consumption operation which the cogeneration system of FIG. 1 implements.

  Below, the cogeneration system 1 which concerns on embodiment of this invention is demonstrated.

  As shown in FIG. 1, the cogeneration system 1 of the present embodiment is a combination of a power generation unit 2 (power generation unit) and a heat recovery device 3, and is formed by connecting them by a reciprocating pipe 5. ing.

  In addition, the cogeneration system 1 includes a heat recovery path 12, a hot water supply path 21, a heat supply path 22, and a storage path 23 (storage) as main flow paths connecting the power generation unit 2 and the devices in the heat recovery apparatus 3. In addition, a plurality of short-circuit paths are provided to communicate these flow paths with each other.

  Furthermore, in the cogeneration system 1 of the present embodiment, fuel gas (for example, gas such as city gas or LPG) is supplied from a gas supply source (not shown) via a gas supply path 13 (fuel supply system).

Here, in the cogeneration system 1 of the present embodiment, on the condition that power generation is continuously performed in the power generation unit 2 for a long time, an operation for increasing the amount of fuel gas supplied to the cogeneration system 1 by a predetermined amount or more is performed. That is, the fuel gas consumption operation is performed. In other words, the cogeneration system 1 of the present embodiment can forcibly change the flow rate of the fuel gas flowing through the gas supply path 13.
Therefore, even when the cogeneration system 1 is operated for a long time, the flow rate of the fuel gas does not continue to flow for a predetermined time or more without greatly changing unlike when a gas leak or the like occurs. As a result, the safety shut-off function that forcibly shuts off the fuel gas supply when a gas leak or the like occurs does not operate inappropriately.

  The cogeneration system 1 of the present embodiment will be described in further detail below.

  First, the main structure of the cogeneration system 1 of this embodiment is demonstrated.

  The power generation unit 2 includes a fuel cell 6 that is a main component and a cooling means 7 that cools the fuel cell 6.

  The fuel cell 6 uses a fuel cell that operates at a high temperature. In this embodiment, a solid oxide fuel cell (so-called SOFC) is employed.

  The cooling means 7 includes a power generation side flow path 8 through which hot water flows and a power generation side heat exchanger 10 and a power generation side circulation pump 11 disposed in the power generation side flow path 8.

  The power generation side circulation pump 11 is a device for circulating hot water through a heat recovery path 12 (FIG. 2) having the reciprocating pipe 5 as a component. The power generation side circulation pump 11 is a spiral pump and includes a motor (not shown). And the flow volume of the hot water which flows through the path | route 12 for heat recovery can be increased / decreased by changing the rotation speed of a motor.

  That is, the power generation unit 2 passes through the power generation side heat exchanger 10 by a function as a power generation device for supplying power to an external power load and heat generated by the power supply. It is the structure also provided with the function as a thermal energy generation device which heats the hot and cold water.

  The heat recovery apparatus 3 includes a storage tank 15, an auxiliary heat source machine 16 (auxiliary heat source unit), a heat exchanger heat exchanger 17, and a bath reheating heat exchanger 18 as main components. . The heat appliance heat exchanger 17 and the bath reheating heat exchanger 18 are heat supply heat exchangers capable of supplying heat to the outside.

  The storage tank 15 is a sealed tank for storing hot water, and can form a temperature stratification of the hot water therein. The storage tank 15 has a heat recovery path 12, a hot water supply path 21, and a heat supply path 22 with respect to the top connection portions 25 and 26 provided at the top and the bottom connection portions 27 and 28 provided at the bottom. The pipes to be configured are connected. In addition, although it is recommended that the top connection portions 25 and 26 and the bottom connection portions 27 and 28 are provided in two openings as in the present embodiment, one connection may be provided for each.

  Furthermore, the storage tank 15 has a configuration in which a plurality (four in this embodiment) of tank temperature sensors 30a to 30d are arranged in the direction of rising (height direction) of hot water stored therein. The tank temperature sensors 30a to 30d function as temperature detection means for detecting the temperature of hot water in the storage tank 15 and detect the remaining amount of hot water in the storage tank 15 at a predetermined temperature or a predetermined temperature range. It also serves as a remaining amount detection means.

Here, in general, when hot water is stored in a storage tank, the hot water is divided into layers for each temperature if the temperature difference between the hot water and the hot water is a predetermined threshold value (about 10 degrees Celsius). Therefore, the hot water passing through the heat recovery path 12 is heated to a temperature higher than the threshold temperature with respect to the temperature of the hot water in the storage tank 15, and is slowly returned to the extent that the hot water in the storage tank 15 is not disturbed. Then, the hot water stored in the storage tank 15 is divided into layers for each temperature (temperature stratification). That is, a high temperature layer accumulated in the upper part of the storage tank 15 and a low temperature layer accumulated in the lower part are formed.
Therefore, by checking the detection temperatures of the tank temperature sensors 30a to 30d installed in the storage tank 15, it is possible to detect how much hot water heated to a desired temperature range is stored in the storage tank 15. .

  The auxiliary heat source unit 16 is the same as a conventionally known water heater. The auxiliary heat source unit 16 includes a burner 31 for burning a fuel gas such as city gas or LPG and an auxiliary heat source side heat exchanger 32, and uses hot energy generated by the combustion of fuel to supply hot water. It is for heating.

  Next, main paths (hot water flow paths) in the cogeneration system 1 of the present embodiment will be described.

  As described above, the cogeneration system 1 of the present embodiment mainly includes the heat recovery path 12, the hot water supply path 21, the heat supply path 22, and the storage path 23. Hereinafter, each route will be described in detail.

  First, the heat recovery path 12 will be described.

As shown in black in FIG. 2, the heat recovery path 12 has an annular shape including the power generation side circulation pump 11 and the power generation side heat exchanger 10 in the power generation unit 2 and the storage tank 15 in the heat recovery device 3. This is a connected flow path, and is a flow path capable of circulating hot water between the power generation side heat exchanger 10 and the storage tank 15. Specifically, the heat recovery path 12 includes a heat recovery flow path 37 through which hot water flows from the storage tank 15 toward the power generation side heat exchanger 10, and hot water from the power generation side heat exchanger 10 toward the storage tank 15. And a heat recovery bypass passage 40 that bypasses the storage tank 15.
That is, the upstream side of the heat recovery forward flow path 37 is connected to the bottom connection portion 27 of the storage tank 15, and the downstream side of the heat recovery return flow path 38 is connected to the top connection portion 25 of the storage tank 15. Furthermore, the heat recovery bypass passage 40 is connected so as to short-circuit the intermediate portion between them, thereby forming the heat recovery passage 12.

  In addition, the heat recovery forward flow path 37 includes a three-way valve 41 that is a flow path switching means that enables the flow path to be switched midway, a radiator temperature sensor 47 that detects the temperature of hot water, and a radiator 42 that is a heat dissipation means. A forward temperature sensor 43 and an antifreezing heater 44 are provided.

  The three-way valve 41 has three ports 41a to 41c and can switch the flow path to two paths. That is, in the three-way valve 41, when the port 41a and the port 41c are communicated with each other, the other port 41b is closed, and the heat recovery forward flow path 37 can be made to flow. Further, in the three-way valve 41, when the port 41b and the port 41c communicate with each other, the other port 41a is closed, and the heat recovery bypass flow path 40 can be in a flowable state.

  The antifreeze heater 44 is a so-called ceramic heater in which a heating element is built in alumina or ceramics formed into a flat plate shape as a heater. The anti-freezing heater 44 can heat piping and the like that form the heat recovery forward flow path 37 by heat generated by energization. More specifically, the hot water flowing through the heat recovery forward flow path 37 can be heated by heating the piping or the like forming the heat recovery forward flow path 37.

  The radiator 42 includes a fan 45 and employs a radiator that lowers the temperature of hot water passing therethrough due to an air cooling effect. The fan 45 of the radiator 42 can control power based on the temperature detected by the radiator temperature sensor 47.

  The outgoing side temperature sensor 43 detects the temperature of the hot water flowing through the heat recovery outgoing passage 37.

  A return-side temperature sensor 46 is provided midway in the heat recovery return flow path 38. These are all arranged on the upstream side (the power generation side heat exchanger 10 side) of the connection part of the heat recovery bypass flow path 40 connected to the heat recovery return flow path 38.

  This is the end of the description of the heat recovery path 12.

  Next, the hot water supply path 21 will be described.

  The hot water supply path 21 is a flow path for discharging hot water having a desired temperature to the outside. That is, the hot water supply path 21 has a water supply channel 50 located upstream from the storage tank 15 and a hot water supply located downstream from the storage tank 15 with reference to the water supply source, as shown in black in FIG. A flow path 51 is used.

  The water supply channel 50 is connected to the bottom connection portion 28 of the storage tank 15. Thereby, the cogeneration system 1 is configured such that low-temperature hot water supplied from the outside can be introduced from the bottom side of the storage tank 15.

  A water supply temperature sensor 52 that detects the temperature of hot water supplied from the outside, a check valve 53, and a three-way valve 55 that serves as a flow path switching unit are provided in the middle of the water supply flow path 50. Yes.

  The three-way valve 55 is substantially the same as the structure of the three-way valve 41 in the heat recovery path 12 (see FIG. 2), and has three ports 55a to 55c. That is, in the three-way valve 55, when the port 55a and the port 55b communicate with each other, the other port 55c is closed, and the upstream water supply channel 50a located on the upstream side (water supply source side) of the water supply channel 50 and the water supply channel It is possible to circulate with the downstream side water supply flow path 50b located on the downstream side of the 50 (the storage tank 15 side). Further, when the port 55a and the port 55c communicate with each other, the other port 55b is closed, and the upstream side water supply flow path 50a and the feed water / hot water connection flow path 56 are allowed to flow.

  The hot water flow path 51 is a flow path that is connected to the top connection portion 26 of the storage tank 15 and leads to the hot water tap or the recirculation circulation path 35. That is, a bath-side branch 57 that communicates with the recirculation circulation channel 35 is connected in the middle of the hot water flow channel 51.

  Further, in the middle of the hot water flow passage 51, a high temperature side temperature sensor 58, a hot water mixing valve 60 having three ports, a flow rate sensor 61, a proportional valve 62, and a hot water temperature sensor 63 are sequentially arranged from the upstream side. Is provided. The hot water / water mixing valve 60 is connected to a water supply branch 65 that branches from the water supply passage 50. The water supply branch 65 is a flow path for joining the hot water supplied from the outside with the hot water flowing through the hot water flow path 51.

  A check valve 66 is provided in the midstream of the water supply branch 65 to prevent the hot water from flowing backward from the hot water flow channel 51 side toward the water supply source side. Downstream of this, it is connected to the hot and cold mixing valve 60.

  That is, the hot water passing through the hot water flow path 51 is adjusted to a desired temperature by mixing hot and cold hot water with the hot water mixing valve 60, and is controlled to a desired flow rate with the proportional valve 62.

  Above, description about the hot water supply path | route 21 is complete | finished.

  Next, the heat supply path 22 will be described.

  As shown in black in FIG. 4, the heat supply path 22 includes a heat appliance flow path 67 provided with a heat exchanger heat exchanger 17 and a bath reheating flow provided with a bath reheating heat exchanger 18. The circulation channel is formed to include the channel 68.

  Specifically, the heat supply path 22 includes a hot water branch flow path 70 branched from the hot water flow path 51 (see FIG. 3), an auxiliary heat source bypass flow path 97 that bypasses the auxiliary heat source unit 16, and an auxiliary heat source downstream. A side flow path 98, a heat exchange flow path 71, a heat appliance flow path 67 branched from the heat exchange flow path 71, a bath reheating flow path 68, and a heat exchange return flow path 72 are formed. It is a flow path.

  The hot water branch channel 70 is formed by an upstream hot water branch channel 70a and a downstream hot water branch channel 70b, and a three-way valve 73 serving as a channel switching means is provided between them. Then, on the downstream side of the three-way valve 73, in order from the upstream side (the storage tank 15 side), the circulation pump 76, the auxiliary heat source incoming water temperature sensor 77, the auxiliary heat source flow rate sensor 78, and the auxiliary heat source three-way valve 80, Is provided.

  The auxiliary heat source bypass flow path 97 is a flow path that is connected to the downstream side of the auxiliary heat source three-way valve 80 and bypasses the auxiliary heat source device 16. The auxiliary heat source bypass flow path 97 merges with the auxiliary heat source side flow path 90 passing through the auxiliary heat source machine 16 at the junction 94. That is, the auxiliary heat source bypass flow path 97 is a flow path that connects the auxiliary heat source three-way valve 80 and the merging portion 94.

  The auxiliary heat source side flow path 90 is a flow path that is connected to the downstream side of the auxiliary heat source three-way valve 80 and passes through the auxiliary heat source unit 16 and passes through the auxiliary heat source side heat exchanger 32. .

  The auxiliary heat source downstream channel 98 is a channel provided downstream of the auxiliary heat source channel 90 and the auxiliary heat source bypass channel 97. In addition, an auxiliary heat source downstream temperature sensor 81 is provided in the auxiliary heat source downstream flow path 98.

  The circulation pump 76 is a pump that is activated when hot water is circulated through the heat supply path 22.

The auxiliary heat source incoming water temperature sensor 77 and the auxiliary heat source flow rate sensor 78 detect the temperature and flow rate of hot water flowing upstream of the auxiliary heat source unit 16. The auxiliary heat source downstream temperature sensor 81 detects the temperature of hot water flowing on the downstream side of the auxiliary heat source unit 16.
Accordingly, the temperature and flow rate of hot water entering the auxiliary heat source unit 16 can be detected by the auxiliary heat source incoming temperature sensor 77 and the auxiliary heat source flow rate sensor 78, and the auxiliary heat source downstream temperature sensor 81 can output the hot water from the auxiliary heat source unit 16. The temperature of the hot and cold water can be detected. That is, the combustion amount of the auxiliary heat source unit 16 is determined based on information detected by these sensors.

  The three-way valve 73 has three ports 73 a to 73 c, and opens a flow path for flowing hot water from the storage tank 15 to the hot water branch flow path 70 side, or supplies hot water from the feed water hot water connection flow path 56 to the hot water branch flow path 70. It is possible to open the flow path flowing in. Similarly, the auxiliary heat source three-way valve 80 also has three ports 80a to 80c, and opens a flow path for flowing hot water in the tapping branch flow path 70 to the auxiliary heat source apparatus 16 or bypasses the auxiliary heat source apparatus 16. The flow path to be opened can be opened.

  The heat transfer flow path 71 is a flow from the branch section 92 connected to the downstream end of the auxiliary heat source downstream flow path 98 to the branch section 82 to the heat appliance flow path 67 and the bath reheating flow path 68. Road.

  The heat appliance flow path 67 is a flow path from the branch portion 82 through the heat appliance heat exchanger 17 to the junction 83 to the heat exchange return flow path 72. The heat appliance flow path 67 is provided with an electromagnetic valve 85 on the downstream side of the heat appliance heat exchanger 17.

  The bath reheating flow path 68 is a flow path from the branch portion 82 through the bath reheating heat exchanger 18 to the junction 83 to the heat exchange return flow path 72. The bath reheating flow path 68 is provided with an electromagnetic valve 86 on the downstream side of the bath reheating heat exchanger 18.

  The heat exchange return channel 72 is a channel from the junction 83 to the storage tank 15.

  The heat exchange return channel 72 is provided with a temperature sensor 93, a flow rate sensor 95, and the above-described three-way valve 55 in the middle.

  Opening and closing of the three-way valves 73 and 80 of the outgoing hot water branching channel 70, the electromagnetic valve 85 of the heating device channel 67, the electromagnetic valve 86 of the bath reheating channel 68, and the three-way valve 55 in the heat exchange return channel 72, respectively. The state is controlled and the operation of the circulation pump 76 is controlled, whereby the water flow in the heat supply path 22 is controlled.

  This is the end of the description of the heat supply path 22.

  Next, the storage path 23 will be described.

  As shown in black in FIG. 5, the storage path 23 includes an auxiliary heat source side channel 90 that passes through the inside of the auxiliary heat source unit 16 from the bottom connection portion 28 of the storage tank 15 to the top connection portion 26. It is the circulation channel formed so that it may contain.

Specifically, the storage path 23 includes, from the upstream side (the bottom of the storage tank 15) side, a downstream water supply channel 50b, a feed water and hot water connection channel 56, a downstream hot water branch flow channel 70b, and an auxiliary heat source side. This is a flow path formed by the flow path 90, the auxiliary heat source downstream flow path 98, the branch path 87, and a part of the hot water flow path 51.
For easier understanding, if attention is paid to the hot water flowing through the storage path 23, the hot water discharged from the bottom connection portion 28 of the storage tank 15 flows into the downstream water supply channel 50 b and passes through the three-way valve 55. Then, it is introduced into the feed water / hot water connection channel 56. Further, the three-way valve 73, the downstream hot water branching flow path 70 b, the auxiliary heat source three-way valve 80, the auxiliary heat source side flow path 90, and the junction 94 are sequentially passed to the auxiliary heat source downstream flow path 98. And it flows into the branch path 87 from the branch part 92 located in the downstream edge part of the auxiliary | assistant heat source downstream flow path 98, and flows into the hot water flow path 51 from the branch path 87. FIG. Then, the hot water flows toward the storage tank 15 and flows into the storage tank 15 from the top connection portion 26 of the storage tank 15. That is, a part of the hot water flow path 51 between the part connected to the top connection part 26 of the storage tank 15 and the connection part 99 between the hot water flow path 51 and the branch path 87 is a hot water. Flows toward the storage tank 15 side.

The hot water supply / hot water connection flow path 56 is a flow path branched from the water supply flow path 50, and the hot water passing through the port 55 c of the three-way valve 55 leads to the port 73 c of the three-way valve 73 provided in the hot water branch flow path 70. It is. Therefore, hot water supplied from a water supply source (not shown) can flow into the hot water branch flow path 70 without introducing the hot water into the storage tank 15 by flowing into the hot water supply hot water connection flow path 56. In addition, hot water discharged from the bottom of the storage tank 15 can flow into the hot water branch flow path 70 by flowing into the feed water / hot water connection flow path 56.
Further, a temperature sensor 101 is provided in the middle of the feed water / hot water connection channel 56.

The branch path 87 is connected to the branch section 92 at the downstream end of the auxiliary heat source downstream flow path 98. That is, the branch path 87 is one of the two channels (the heat transfer channel 71 and the branch channel 87) that branches at the downstream end of the auxiliary heat source downstream channel 98.
Further, in the middle of the branch path 87, a temperature sensor 102 and a proportional valve 91 are provided in order from the branch section 92 side.

  Above, the description about the storage path | route 23 is complete | finished.

  Next, the gas supply path 13 will be described.

The gas supply path 13 is constituted by a gas pipe drawn into a house or the like and a microcomputer meter 4 provided therein.
The gas supply path 13 of the present embodiment is branched into two paths at the branch section 100. Specifically, it branches into a power generation side gas supply path 104 that supplies fuel gas to the power generation unit 2 and an auxiliary heat source side gas supply path 105 that supplies fuel gas to the auxiliary heat source unit 16. The fuel gas is supplied to the reformer (not shown) of the power generation unit 2 and the burner 31 of the auxiliary heat source unit 16.

  Further, on the upstream side of the branch portion 100 of the gas supply path 13, a microcomputer meter 4 (supply cutoff means) having a function of cutting off the supply of gas for safety is provided.

  The microcomputer meter 4 has a safety shut-off function that automatically shuts off the flow of the fuel gas when the fuel gas flows for a predetermined time ta or more in a state where there is no great change in the flow rate of the fuel gas. At this time, the time ta from when the fuel gas starts to flow until the fuel gas flow is automatically cut off varies depending on the flow rate of the fuel gas. That is, when the flow rate of the fuel gas is relatively high, the time ta until the cutoff is relatively short, and when the flow rate of the fuel gas is relatively low, the time ta until the cutoff is relatively long.

  Further, the operation of the cogeneration system 1 of the present embodiment is controlled by a control device (not shown). The components provided in the control device are the same as those provided in a conventionally known cogeneration system, and can be configured to include, for example, a CPU and a memory in which a predetermined control program is incorporated. Based on the detection signals of the sensors provided in each part, the data stored in the memory, etc., the control device includes a valve, a power generation unit 2, an auxiliary heat source unit 16 and the like provided in each part of the cogeneration system 1. The operation is controlled to optimize the total energy efficiency of the cogeneration system 1.

  Subsequently, the operation in the normal operation mode of the cogeneration system 1 of the present embodiment will be described. In addition, since the normal driving | operation operation | movement of the cogeneration system 1 of this embodiment is as substantially the same as a well-known technique, it demonstrates easily.

The cogeneration system 1 of this embodiment is an operation operation mode for heat consumption selected from a heat storage operation mode in which a heat storage operation is performed independently, and an operation mode group including a hot water supply operation mode, a reheating operation mode, and a heating operation mode. It is possible to select and operate.
Each operation mode will be described below.

(Heat storage operation mode)
In the heat storage operation mode, by operating the power generation side circulation pump 11, a water flow is generated in the heat recovery path 12, the exhaust heat generated along with the operation of the power generation unit 2 is recovered, and hot water is heated. This is an operation mode in which a heat storage operation for storing hot water in the storage tank 15 is performed. That is, when the cogeneration system 1 operates in the heat storage operation mode, the three-way valve 41 is closed with respect to the heat recovery bypass flow path 40 based on a control signal transmitted from a control device (not shown), and the heat recovery forward flow path 37. The heat recovery return flow path 38 is controlled to be open. Then, a circulating flow of hot water is generated from the bottom of the storage tank 15 toward the top of the storage tank 15 via the power generation unit 2.

  Here, in the heat storage operation mode, when the temperature of the hot water flowing through the heat recovery return flow path 38 is low, an operation of circulating hot water in the heat recovery return flow path 38 is performed. That is, when the temperature of the hot water flowing through the heat recovery return flow path 38 is low, the open port of the three-way valve 41 is switched so that the hot water flows from the heat recovery return flow path 38 to the heat recovery bypass flow path 40 side. .

  That is, in the heat storage operation mode, the flow rate of hot water flowing through the heat recovery path 12 is controlled so that hot water of a predetermined temperature flows into the storage tank 15 based on a predetermined hot water storage set temperature. If hot water of a predetermined temperature cannot flow into the storage tank 15, a circulation path of the heat recovery path 12 (circulation path formed by the heat recovery forward flow path 37, the heat recovery return flow path 38, and the heat recovery bypass flow path 40. ) Is circulating hot water.

(Hot water operation mode)
In the hot water supply operation mode, a water flow is formed by the above-described hot water supply path 21 so that the hot hot water stored in the storage tank 15 and the low temperature hot water passing through the water supply branch 65 are merged and adjusted to a predetermined temperature. In this mode, the hot water is discharged from the hot water tap (including dropping into the bathtub).
More specifically, when a hot water tap or the like is operated, a part of low-temperature hot water supplied from an external water supply source flows into the storage tank 15 from the bottom connection portion 28. Thereby, hot hot water staying at the top of the storage tank 15 is discharged to the hot water flow path 51. At this time, low-temperature hot water supplied from an external water supply source flows not only into the storage tank 15 but also into the water supply branch 65. As a result, the hot water discharged to the hot water flow channel 51 and the hot water flowing into the water supply branch 65 are merged through the hot water mixing valve 60 and flow into a hot water tap or a tub (not shown) to supply hot water.
In addition, during the hot water supply operation mode, the heat storage operation is basically performed at all times. That is, when the cogeneration system 1 using SOFC operates in the hot water supply operation mode, both the heat storage operation and the hot water supply operation are performed.

(Fast driving mode)
The reheating operation mode is an operation mode in which hot water is supplied to the reheating heat exchanger 18 through the heat supply path 22 and the hot water in the bathtub is circulated in the recirculation circulation channel 35. That is, the hot hot water circulating in the heat supply path 22 (the bath reheating flow path 68) and the hot water in the bathtub circulating in the reheating circulation flow path 35 exchange heat. As a result, the hot water in the bathtub is heated to a desired temperature.
It should be noted that the heat storage operation is basically always performed even during the reheating operation mode. That is, when the cogeneration system 1 using the SOFC operates in the reheating operation mode, the heat storage operation and the reheating operation for supplying high-temperature hot water to the reheating heat exchanger 18 are performed.

(Heating operation mode)
In the heating operation mode, high-temperature hot water is supplied to the heat exchanger 17 for heat appliances through the heat supply path 22 described above, and hot water (heat for supplying heat to a heating device (not shown) in the heating circulation channel 36 is also provided. A circulating flow of the medium). As a result, the hot water that circulates through the heat supply path 22 (heat appliance flow path 67) and the hot water that serves as a heat medium that circulates through the heating circulation path 36 exchange heat. As a result, heat is supplied to a heating device (not shown).

  The above is the description of the operation in the operation mode for normal heat consumption.

  In addition, when the temperature of the hot water stored in the storage tank 15 is low when implementing each operation mode of the hot water supply mode, the reheating operation mode, and the heating operation mode, the hot water discharged from the storage tank 15 is supplemented. In some cases, the heat source device 16 may be heated.

  Here, as described above, in the cogeneration system 1 of the present embodiment, the microcomputer meter 4 is provided in the power generation unit 2 and the gas supply path 13 for supplying the fuel gas to the auxiliary heat source unit 16. The microcomputer meter 4 has a safety shut-off function that automatically shuts off the gas supply when an abnormal situation such as gas leakage occurs. In other words, the microcomputer meter 4 automatically shuts off the gas supply for safety when the fuel gas continues to flow for a certain period of time without significant change in the flow rate of the fuel gas.

  However, when the cogeneration system 1 is operated for a long time and there is no significant change in the amount of fuel gas supplied during operation, an abnormal situation such as gas leakage occurs as a result in the gas supply path 13. The situation will be similar. That is, in the gas supply path 13, a situation occurs where the gas continues to flow for a predetermined time or longer without the gas flow rate changing greatly. Under such circumstances, the microcomputer meter 4 cannot determine whether it is a normal operation or whether an abnormality such as a gas leak has occurred, and this is due to the normal operation of the cogeneration system 1. However, the gas supply is automatically shut off for safety.

  Therefore, in the cogeneration system 1 of the present embodiment, under the condition that the normal operation is performed, the power generation by the power generation unit has been continued for a predetermined time or longer so that the safety shut-off function of the microcomputer meter 4 does not operate. The fuel gas consumption operation is forcibly implemented. Thereby, since the flow rate of the gas flowing through the gas supply path 13 changes, the microcomputer meter 4 can reliably determine that the normal operation is being performed. Therefore, the cogeneration system 1 can be operated for a long time without invalidating the safety shut-off function of the microcomputer meter 4.

  The fuel gas consumption operation which is a characteristic operation of the present embodiment will be described in detail below with reference to FIG.

  In the fuel gas consumption operation of the present embodiment, when the power generation continuation time of the fuel cell 6 integrated by a control device (not shown) exceeds a predetermined time t1 (Yes in Step 1), the flow proceeds to Step 2. Perform the path switching operation.

  In the flow path switching operation, the ports of the three-way valves 55, 80, 73 are communicated and closed so that hot water flows through the storage path 23 (see FIG. 5). As a result, hot water can be circulated in the storage path 23.

  And it is determined whether the temperature of the hot water in the storage tank 15 is below the predetermined temperature Ta (step 3). Specifically, among the four tank temperature sensors 30a to 30d (see FIG. 1 and the like) arranged in the storage tank 15, the vicinity of the bottom of the storage tank 15 detected by the tank temperature sensor 30d located on the most bottom side. It is determined whether the temperature of the hot water is equal to or lower than a predetermined temperature Ta (for example, 40 degrees Celsius).

When the temperature of the hot water in the storage tank 15 is equal to or lower than the predetermined temperature Ta, the combustion operation is performed with the combustion set temperature of the auxiliary heat source unit 16 set to the predetermined temperature T1 (for example, 70 degrees Celsius) (step 4).
More specifically, a water flow is generated in the storage path 23 by operating the circulation pump 76. Accordingly, the hot water flowing out from the bottom connection portion 28 of the storage tank 15 flows through the storage path 23 and flows into the storage tank 15 again from the top connection portion 26 of the storage tank 15. At this time, in the auxiliary heat source unit 16, the combustion amount of the burner 31 is controlled to be the minimum combustion amount. And the flow volume of the hot water which flows through the storage path | route 23 is restrict | limited so that the temperature of the hot water detected with the auxiliary | assistant heat source downstream temperature sensor 81 may become T1. In this embodiment, the rotational speed of the motor of the circulation pump 76 is controlled by a control device (not shown), and the flow rate of hot water flowing through the storage path 23 is controlled.

  On the other hand, when the temperature of the hot water in the storage tank 15 exceeds the predetermined temperature Ta, the combustion operation is performed with the combustion set temperature of the auxiliary heat source unit 16 set to the predetermined temperature T2 (for example, 75 degrees Celsius) (step 5). Also in this case, a water flow is generated in the storage path 23 by operating the circulation pump 76. The auxiliary heat source unit 16 controls the combustion amount of the burner 31 and becomes the minimum combustion amount necessary for the combustion of the burner 31. And the flow volume of the hot water which flows through the storage path 23 is restrict | limited so that the temperature of the hot water detected with the auxiliary | assistant heat source downstream temperature sensor 81 may become T2.

Here, the combustion set temperature T2 when the temperature of the hot water exceeds the predetermined temperature Ta is higher than the combustion set temperature T1 when the temperature of the hot water is equal to or lower than the predetermined temperature Ta.
That is, in the fuel gas consumption operation of the present embodiment, when the temperature of the hot water in the storage tank 15 is relatively high, the auxiliary heat source unit 16 burns so that the temperature of the hot water flowing into the storage tank 15 becomes relatively high. Carry out driving. On the other hand, when the temperature of the hot water in the storage tank 15 is relatively low, the combustion operation is performed so that the temperature of the hot water flowing into the storage tank 15 is relatively low. As described above, according to the fuel gas consumption operation in which hot water having different temperatures is allowed to flow in accordance with the temperature of the hot water stored in the storage tank 15, the temperature of the hot water in the storage tank 15 is greatly changed by the fuel gas consumption operation. There is nothing. In other words, the temperature stratification formed by the hot water stored in the storage tank 15 is not disturbed by the fuel gas consumption operation.

  And after the combustion operation | movement by the auxiliary heat source machine 16 is started until predetermined time t2 passes (it is No at step 6), the operation | movement after step 3 is implemented. Further, when the predetermined time t2 has elapsed since the combustion operation by the auxiliary heat source device 16 is started (Yes in step 6), the combustion gas consumption operation is ended.

  By performing such a combustion gas consumption operation, the supply amount of the fuel gas supplied to the cogeneration system 1 (the flow rate of the fuel gas flowing through the gas supply path 13) can be changed. Therefore, when the cogeneration system 1 is operated, it does not continue to flow for a predetermined time or more in a state where the flow rate of the gas does not change greatly as in the case where an abnormal situation such as gas leakage occurs. Thus, the cogeneration system 1 can be operated for a long time without invalidating the safety shut-off function of the microcomputer meter 4.

  By the way, as described above, hot water may be heated by the auxiliary heat source device 16 when each operation mode of the hot water supply mode, the reheating operation mode, and the heating operation mode is performed. In other words, in the cogeneration system 1 of the present embodiment, the combustion operation of the auxiliary heat source unit 16 may be performed not only when the fuel gas consumption operation is performed but also when another operation is performed.

  Therefore, in the cogeneration system 1 of the present invention, the power generation continuation time of the fuel cell 6 accumulated by the control device is initially set on condition that the auxiliary heat source unit 16 has performed a combustion operation of a predetermined combustion amount or more for a predetermined time t3 or more. It has become. That is, in the fuel gas consumption operation or other operation, the power generation duration time is integrated from when the auxiliary heat source unit 16 performs the combustion operation.

  More specifically, the microcomputer meter 4 automatically shuts off the flow of the fuel gas when the fuel gas flows through the gas supply path 13 for a predetermined time ta or more in a state where there is no great change in the flow rate of the fuel gas. In other words, the microcomputer meter 4 integrates the time (gas supply duration) during which the fuel gas flows in a state where the flow rate does not change by a predetermined amount or more, and when the gas supply duration reaches the predetermined time ta, Fuel gas is automatically shut off for safety.

  Here, when the auxiliary heat source unit 16 performs the combustion operation, the flow rate of the fuel gas flowing through the gas supply path 13 increases as compared to the case where the auxiliary heat source unit 16 does not perform the combustion operation. Therefore, when the auxiliary heat source unit 16 starts the combustion operation, the microcomputer meter 4 detects that the flow rate of the fuel gas flowing through the gas supply path 13 has increased, and discards the previously accumulated gas supply duration time. The accumulation of the gas supply duration time is newly started.

  At this time, the control device (not shown) of the cogeneration system 1 of the present embodiment initializes the accumulated power generation continuation time of the fuel cell 6 on the condition that the auxiliary heat source unit 16 performs the combustion operation. Yes. For this reason, the start of integration of the power generation duration by the control device and the start of integration of the gas supply duration by the microcomputer meter 4 are substantially the same time. In this way, the safety shut-off function operates by shortening the predetermined time t1 that the control device compares with the power generation continuation time by an appropriate time than the predetermined time ta that the microcomputer meter 4 compares with the gas supply continuation time. The fuel gas consumption operation can be surely performed before. Further, since the safety shut-off function is not executed even though there is sufficient time until the safety shut-off function operates, the cogeneration system 1 can be efficiently operated.

  In the above-described embodiment, the temperature of hot water in the storage tank 15 is detected, and the example in which the combustion set temperature of the auxiliary heat source unit 16 in the fuel gas consumption operation is varied based on the detected temperature has been described. The fuel gas consumption operation performed by the cogeneration system is not limited to this. For example, the temperature of hot water in the storage tank 15 may be detected, and the hot water set temperature may be changed upward based on the detected temperature. The case where such a configuration is adopted for the above-described cogeneration system 1 will be described in detail below.

  In the cogeneration system 1, as described above, in the heat storage operation mode, the hot water flowing through the heat recovery path 12 so that hot water of a predetermined temperature flows into the storage tank 15 based on a predetermined hot water storage set temperature. The flow rate is controlled. At this time, even when hot water heated by the auxiliary heat source device 16 flows into the storage tank 15, the hot water at a predetermined temperature is controlled to flow into the storage tank 15 based on a predetermined hot water storage set temperature. .

Here, when the storage tank 15 is already filled with hot water having a set temperature for storing hot water, the hot water in the storage tank 15 is discharged, heated, and then returned to the storage tank 15. The set temperature may be exceeded.
Therefore, in this embodiment, the temperature of the hot water in the storage tank 15 is detected before the fuel gas consumption operation is performed. And if the inside of the storage tank 15 is filled with the hot water of hot water storage preset temperature, the hot water storage preset temperature will be changed upwards and fuel gas consumption operation will be implemented. As a result, even if hot water heated into the storage tank 15 by the fuel gas consumption operation flows, the hot water in the storage tank 15 does not exceed the hot water set temperature. As a result, the fuel gas consuming operation can be executed even when the storage tank 15 is already filled with hot water having a preset hot water storage temperature.

  Further, as described above, the auxiliary heat source unit 16 is controlled so that hot water flows into the storage tank 15 so that the hot water in the storage tank 15 becomes the hot water set temperature. Therefore, when the hot water storage set temperature is changed upward, the combustion amount of the burner 31 in the auxiliary heat source unit 16 and the temperature of hot water discharged from the auxiliary heat source unit 16 (temperature of hot water detected by the auxiliary heat source downstream temperature sensor 81) Is changed to be higher. That is, similarly to the above case, the temperature of the hot water discharged from the auxiliary heat source unit 16 is controlled according to the temperature of the hot water in the storage tank 15.

  Above, the description about the structure which detects the temperature of the hot water in the storage tank 15 before a fuel gas consumption driving | operation, and changes upwards the hot water storage preset temperature based on the detected temperature is complete | finished.

  In the above-described embodiment, the power generation continuation time in the power generation unit 2 is acquired and integrated by a control device (not shown), but the coordination system of the present invention is not limited to this. For example, a power generation side control device that controls the power generation unit 2 and a heat recovery side control device that controls the heat recovery device 3 may be separately provided, and a signal may be transmitted and received between them. At this time, the power generation continuation time may be integrated by the power generation side control device, and it may be determined whether the power generation continuation time is equal to or longer than the predetermined time t1, and the determination result may be transmitted to the heat recovery side control device. Alternatively, the heat recovery side control device may integrate the power generation continuation time to determine whether the power generation continuation time is equal to or longer than the predetermined time t1. You may change suitably the number of the cogeneration systems of this invention, and allocation of a process.

  In the above-described embodiment, the power generation duration time of the fuel cell 6 accumulated by the control device is initialized on the condition that the auxiliary heat source unit 16 has performed the combustion operation of a predetermined combustion amount or more for a predetermined time t3 or more. However, the cogeneration system 1 of the present invention is not limited to this. For example, on condition that the auxiliary heat source unit 16 has performed the combustion operation of a predetermined combustion amount or more for a predetermined time t3 or more, and the state where the power generation amount of the fuel cell 6 has changed for a predetermined amount or more has continued for a predetermined time t4 or more The power generation duration time of the fuel cell 6 accumulated by the control device may be initialized. That is, when the amount of power generated by the fuel cell 6 changes and the amount of fuel gas consumed by the power generation operation of the fuel cell 6 is predicted or detected, the power generation duration time may be initialized. .

  Furthermore, the fuel cell 6 integrated by the control device based on the sum of the change amount of the fuel gas consumed by the power generation operation of the fuel cell 6 and the change amount of the fuel gas consumed by the combustion operation of the auxiliary heat source unit 16. The power generation duration time may be initialized. More specifically, in this case, since the state in which the power generation amount of the fuel cell 6 has changed by a predetermined amount or more has continued for a predetermined time or longer, the control device supplies the fuel gas supplied to the fuel cell 6 by a predetermined amount X1. Predict or detect that it has only changed. Further, the control device predicts or detects that the fuel gas supplied to the auxiliary heat source unit 16 has changed by a predetermined amount X2 because the auxiliary heat source unit 16 has performed the combustion operation for a predetermined time or more. Then, on the condition that the fuel gas supplied to the entire cogeneration system 1 has changed by a predetermined amount (X1 + X2) has continued for a predetermined time or longer, the power generation continuation time of the fuel cell 6 integrated by the control device is initialized. Turn into. According to such a configuration, the start of integration of the power generation duration by the control device and the start of integration of the gas supply duration by the microcomputer meter 4 can be more reliably performed at substantially the same time, so that the operation of the cogeneration system 1 is performed. Can be made more efficient.

  In the above-described embodiment, when performing the fuel gas consumption operation, the hot water discharged from the auxiliary heat source unit 16 is controlled by setting the combustion amount in the burner 31 as the minimum combustion amount and controlling the flow rate of the hot water flowing through the storage path 23. At a predetermined temperature T1 (or T2). However, the cogeneration system 1 of the present invention is not limited to this. For example, the temperature of hot water discharged from the auxiliary heat source unit 16 may be varied by controlling the amount of combustion in the burner 31. In addition, the combustion amount in the burner 31 may be a combustion amount that minimizes combustion noise instead of the minimum combustion amount, and may be a combustion amount that is larger than the minimum combustion amount for measures against wind resistance of exhaust gas. However, if the combustion amount in the burner 31 is the minimum combustion amount, the amount of fuel gas used in the fuel gas consumption operation can be reduced, which is desirable from the viewpoint of operational efficiency.

  In the above-described embodiment, the example in which the auxiliary heat source unit 16 is provided in the storage path 23 that is a flow path separate from the heat recovery path 12 has been described, but the cogeneration system of the present invention is not limited to this. Absent. The cogeneration system of the present invention may have a configuration in which an auxiliary heat source device is provided in the heat recovery path. Even with such a configuration, the cogeneration system of the present invention can be operated continuously for a long time without invalidating the safety function of the microcomputer meter 4 by performing the fuel gas consumption operation. .

1 Cogeneration system 2 Power generation unit (power generation unit)
4 Microcomputer meter (supply cutoff means)
6 Fuel cell 13 Gas supply path (fuel supply system)
15 Storage tank 16 Auxiliary heat source machine (auxiliary heat source part)
23 Storage route (storage system)

Claims (5)

In a cogeneration system that includes a fuel cell and has a power generation unit that simultaneously generates electric energy and thermal energy, and heats hot water with the heat generated by the power generation unit,
A storage tank for storing hot water, an auxiliary heat source part for heating hot water as required, a storage system for supplying hot water heated by the auxiliary heat source part to the storage tank, and a fuel for the power generation part and the auxiliary heat source part A fuel supply system for supplying gas,
The fuel gas consumption operation is forcibly performed on condition that power generation by the power generation unit has continued for a predetermined time or more, and the fuel gas consumption operation is performed by supplying hot water heated by the combustion operation of the auxiliary heat source unit to the storage tank. A cogeneration system characterized by storage. The fuel supply system is provided with a supply blocking means capable of blocking the supply of fuel gas,
2. The cogeneration system according to claim 1, wherein the supply blocking unit is configured to block the supply of fuel gas when a constant gas flow rate is continuously used. 3. The power generation time by the power generation unit is integrated, and based on the integrated result, it is determined whether the power generation by the power generation unit has continued for a predetermined time,
If the auxiliary heat source unit is subjected to the combustion operation before the fuel gas consumption operation, the power generation is performed on the condition that a certain amount or more of the gas has been consumed or calculated by the operation. The cogeneration system according to claim 1 or 2, wherein an integrated value of time is initialized. Operation to store hot water at the target hot water storage set temperature in the storage tank is possible,
At the start of the fuel gas consumption operation, when the temperature of the hot water in a predetermined portion in the storage tank is equal to or higher than the hot water storage set temperature and the hot water storage tank is filled with hot water, the hot water storage set temperature is changed upward. The cogeneration system according to any one of claims 1 to 3, wherein   The cogeneration system according to any one of claims 1 to 4, wherein in the fuel gas consumption operation, the combustion operation of the auxiliary heat source unit is performed with a predetermined combustion amount.

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