JP5388758B2 - Fuel cell cogeneration system - Google Patents

Description

  The present invention relates to a fuel cell cogeneration system including a power generation unit that generates power and a hot water storage unit that includes a hot water storage tank that stores water (hot water) that has been heat-exchanged using exhaust heat generated by the operation of the power generation unit.

  In recent years, as a next-generation energy, in order to perform heat exchange between a fuel cell that can obtain power using hydrogen-containing gas (fuel gas) and air (oxygen-containing gas), and exhaust gas and water generated during operation A power generation unit (fuel cell device) including a heat exchanger and a hot water storage unit including a hot water storage tank for supplying water to the heat exchanger and storing hot water generated by heat exchange in the heat exchanger. Various fuel cell cogeneration systems have been proposed (see, for example, Patent Document 1).

  In such a fuel cell cogeneration system, high total efficiency can be obtained by supplying hot power generated by the power generation unit to the load and generating hot water using exhaust heat generated by the operation of the power generation unit. it can.

  By the way, in such a fuel cell cogeneration system, a reforming reaction for generating fuel gas for supplying condensed water generated by performing heat exchange between exhaust gas and water in a heat exchanger to a fuel cell. It is known to use. Here, when the temperature of water supplied to the heat exchanger (water stored in the hot water storage tank) rises, the amount of condensed water generated decreases, making it difficult to perform efficient operation. It is known to drain hot water from hot water storage tanks. Therefore, it is preferable to efficiently use the hot water stored in the hot water storage tank.

  Here, in Patent Document 1, in order to efficiently use hot water generated by heat exchange between exhaust heat generated by operation of the power generation unit and water, the current hot water supply temperature of hot water supplied from the hot water storage tank, An example is shown in which information on whether or not the tank is full of hot water is displayed on the operation panel to notify the operator.

JP 2005-78977 A

  By the way, in such a fuel cell cogeneration system, since the use of hot water is started only when the user gives an instruction to start the operation of the load equipment that uses electric power or hot water, If the operation start instruction is not issued, the hot water stored in the hot water storage tank is continuously drained, and the operating efficiency of the fuel cell cogeneration system is reduced.

  Therefore, an object of the present invention is to provide a fuel cell cogeneration system with improved operation efficiency by reducing the amount of water drained outside the hot water stored in the hot water storage tank.

A fuel cell cogeneration system according to the present invention includes a fuel cell device including a fuel cell, a heat exchanger for exchanging heat between the exhaust gas from the fuel cell and water, and water for storing water after heat exchange. A hot water storage tank, a circulation pipe for circulating water between the heat exchanger and the hot water storage tank, a water storage device for storing water in the hot water storage tank, and water stored in the hot water storage tank and temperature sensors for measuring the drainage device for draining water to the outside or the water storage device, the temperature of the water storage water before Symbol hot water tank, the water temperature measured by the prior SL temperature sensor A control device for controlling the operation of the drainage device so as to supply water stored in the hot water storage tank to the water storage device when measured at a first predetermined temperature or higher continuously for a predetermined time. It is characterized by that.

  In such a fuel cell cogeneration system, when the temperature of the water measured by the temperature sensor is measured at a first predetermined temperature or higher continuously for a predetermined time, the water is conventionally discharged to the outside as it is. By controlling the operation of the drainage device so that water (hot water) is automatically supplied to the water storage device, the hot water generated by heat exchange can be used efficiently, and the operating efficiency (total efficiency) An improved fuel cell cogeneration system can be obtained.

  Further, the fuel cell cogeneration system of the present invention includes a notification device, and the control device continuously measures a temperature of water measured by the temperature sensor at a first predetermined temperature or higher for a predetermined time. The alarm device is activated, and when the temperature of the water measured by the temperature sensor is continuously measured at a first predetermined temperature or higher after a predetermined time has elapsed since the alarm device was activated. The operation of the drainage device is preferably controlled so that the water stored in the hot water storage tank is supplied to the water storage device.

  In such a fuel cell cogeneration system, before supplying the water stored in the hot water storage tank to the water storage device, the alarm device is activated to allow the user of the fuel cell cogeneration system to store the water in the hot water storage tank. The hot water generated by heat exchange can be used efficiently.

  Further, in this case, when the temperature of the water measured by the temperature sensor is continuously measured at the first predetermined temperature or more after a predetermined time has elapsed since the alarm device is operated, the water is stored in the hot water storage tank. By controlling the operation of the drainage device so that water is automatically supplied to the water storage device, the hot water generated by heat exchange can be used efficiently, and fuel with improved operational efficiency (overall efficiency) It can be a battery cogeneration system.

  In the fuel cell cogeneration system of the present invention, when the control device controls the operation of the drainage device so that the water stored in the hot water storage tank is supplied to the water storage device, the notification device is provided. It is preferable to perform control to be operated.

  In such a fuel cell cogeneration system, when the operation of the drainage device is controlled so as to supply the water stored in the hot water storage tank to the water storage device, the user can store the water by operating the notification device. It can be easily recognized that the supply of water stored in the hot water storage tank to the apparatus has started.

  In the fuel cell cogeneration system of the present invention, the drainage device supplies an external drain pipe having a valve for draining the water in the hot water storage tank to the outside, and supplies the water in the hot water storage tank to the water storage device. It is preferable to comprise a water storage device supply pipe provided with a valve for this purpose.

  In such a fuel cell cogeneration system, an external drain pipe having a valve for draining the water in the hot water storage tank to the outside, and a water storage device supply having a valve for supplying the water in the hot water storage tank to the water storage device Since the pipe is provided, it is possible to easily control whether the water in the hot water storage tank is discharged to the outside or supplied to the water storage device.

  Further, in the fuel cell cogeneration system of the present invention, the drainage device includes a drain pipe provided with a valve for draining water of the hot water storage tank, and an external drain pipe for draining water of the hot water storage tank to the outside. A water storage device supply pipe for supplying water from the hot water storage tank to the water storage device, and the drainage pipe, the external drainage pipe, and the water storage device supply pipe are connected by a three-way valve. It is preferable.

  In such a fuel cell cogeneration system, a drain pipe provided with a valve for draining hot water tank water, an external drain pipe for draining hot water tank water to the outside, and storing hot water tank water. Since the water storage device supply pipe for supplying to the device is connected by a three-way valve, it is possible to easily control whether the water in the hot water storage tank is drained to the outside or supplied to the water storage device.

  The fuel cell cogeneration system of the present invention includes a water storage device water level sensor for measuring a water level of the water storage device, and the control device is based on information from the water storage device water level sensor, When the water level of the water storage device is equal to or higher than a predetermined water level, the supply of water from the hot water storage tank to the water storage device is stopped, and the water stored in the hot water storage tank is drained to the outside. It is preferable to control the operation of the drainage device.

  In such a fuel cell cogeneration system, when the water level of the water storage device becomes equal to or higher than a predetermined water level, supply of water stored in the hot water storage tank to the water storage device is stopped and drained to the outside. By controlling the operation of the drainage device as described above, it is possible to suppress the overflow of water from the water storage device.

  In addition, the fuel cell cogeneration system of the present invention includes a water storage device temperature sensor for measuring the temperature of the water stored in the water storage device, and the control device is measured by the water storage device temperature sensor. It is preferable to control the operation of the drainage device so that the water stored in the hot water storage tank is drained to the outside when the temperature of the water stored in the stored water storage device becomes equal to or higher than a predetermined temperature.

  In such a fuel cell cogeneration system, when the temperature of the water stored in the water storage device becomes equal to or higher than a predetermined temperature, the operation of the drainage device so as to drain the water stored in the hot water storage tank to the outside. By controlling the above, the temperature of the water stored in the water storage device can be set within a predetermined temperature range.

  The fuel cell cogeneration system of the present invention comprises a water supply device for supplying water to the hot water storage tank, and a hot water storage tank water level sensor for measuring the water level of the hot water storage tank, and the control device comprises: The operation of the drainage device and the water supply device is controlled so that the water level of the hot water storage tank measured by the hot water storage tank water level sensor is within a predetermined range, and the temperature of the water measured by the temperature sensor is It is preferable to control the operation of the drainage device so as to stop draining water from the hot water storage tank when the temperature becomes lower than a second predetermined temperature set lower than the first predetermined temperature.

  In such a fuel cell cogeneration system, the operation of the water supply device for supplying water to the drainage device and the hot water storage tank is controlled so that the water level of the hot water storage tank is within a predetermined range, and a temperature sensor is used. When the measured water temperature is lower than a second predetermined temperature set lower than the first predetermined temperature, the operation of the drainage device is controlled to stop draining water from the hot water storage tank. As a result, the temperature of the water stored in the hot water storage tank can be prevented from excessively decreasing, and hot water used by the user of the fuel cell cogeneration system can be efficiently generated.

  The fuel cell cogeneration system of the present invention can reduce the amount of water drained to the outside by automatically supplying water (hot water) stored in a hot water storage tank to a water storage device, thereby reducing operating efficiency ( Overall efficiency) can be improved.

It is a block diagram which shows an example of a structure of the fuel cell cogeneration system of this invention. It is a flowchart which shows an example of the flow of control of the fuel cell cogeneration system of this invention. FIG. 3 is a flowchart showing an example of a control flow of the fuel cell cogeneration system of the present invention, showing a continuation of the flowchart shown in FIG. 2. It is a block diagram which shows another example of a structure of the fuel cell cogeneration system of this invention. It is a block diagram which shows another example of a structure of the fuel cell cogeneration system of this invention.

  FIG. 1 is a configuration diagram showing an example of a fuel cell cogeneration system (hereinafter sometimes abbreviated as a cogeneration system) of the present invention. In the following drawings, the same numbers are assigned to the same members.

  The cogeneration system shown in FIG. 1 includes a power generation unit (fuel cell device) that generates power, a hot water storage unit that stores hot water after heat exchange, and a circulation pipe that circulates water between these units. It is configured.

  The power generation unit (fuel cell device) shown in FIG. 1 includes a fuel cell stack 1 (hereinafter sometimes abbreviated as a cell stack) formed by combining a plurality of fuel cells (not shown), and the cell stack 1. The heat exchanger 5 for exchanging heat between the exhaust gas and water is provided. First, each member which comprises a power generation unit (fuel cell apparatus) is demonstrated below.

  The power generation unit (fuel cell device) includes a raw fuel supply device 2 for supplying raw fuel such as natural gas, an oxygen-containing gas supply device 3 for supplying oxygen-containing gas to the fuel cells constituting the cell stack 1, A reformer 4 that performs steam reforming with fuel and steam is provided. The reformer 4 vaporizes water (pure water, which may be abbreviated as appropriate hereinafter) supplied by a water pump 11 described later, and supplies the raw fuel and steam supplied from the raw fuel supply device 2. A vaporizing section for mixing and a reforming catalyst for generating a fuel gas (hydrogen-containing gas) by reacting the mixed raw fuel and water vapor are provided.

  In addition, the fuel cell module which comprises a power generation unit is comprised by accommodating the cell stack 1 and the reformer 4 in a storage container. In FIG. 1, each device constituting the fuel cell module is surrounded by a two-dot chain line (indicated by M in FIG. 1).

  Further, a part of the circulation pipe 16 for circulating water for heat exchange with the exhaust gas from the cell stack 1 in the heat exchanger 5 and the condensed water generated in the heat exchanger 5 are supplied to the reformer 4. A condensed water supply pipe 6 is provided to supply the condensed water, and the condensed water generated by the heat exchanger 5 is processed into pure water by the condensed water treatment device 7 and then stored in the water tank 8. Then, the water pump 11 supplies the reformer 4 (vaporizer, not shown). The condensed water treatment device 7 and the water tank 8 are connected by a tank connecting pipe 9, and the water tank 8 and the reformer 4 are connected by a reforming water supply pipe 10.

  Furthermore, the power generation unit (fuel cell device) shown in FIG. 1 converts supply power for converting DC power generated by the fuel cell into AC power, and adjusting the supply amount of the converted current to the external load. In addition to the outlet water temperature sensor 14 for measuring the water temperature of the water (circulating water flow) that is provided at the outlet of the heat exchanger 5 and that flows through the outlet of the heat exchanger 5, a control device 13 is provided. The power generation unit is configured together with a circulation pump 15 that circulates water in the circulation pipe 16. The circulation pump 15 can also be arranged on the hot water storage unit side. And by storing each device constituting these power generation units in an exterior case, a power generation unit (fuel cell device) that can be easily installed and carried can be obtained (not shown).

  In addition, between the cell stack 1 and the heat exchanger 6, there is provided an exhaust gas treatment device (not shown) for treating exhaust gas generated during the operation of the fuel cell (cell stack 1). In addition, the exhaust gas treatment apparatus accommodates an exhaust gas treatment member in a storage container, and a generally known combustion catalyst can be used as the exhaust gas treatment member.

  The hot water storage unit includes a hot water storage tank 17 for storing hot water after heat exchange. A hot water storage tank 17 shown in FIG. 1 includes a hot water storage tank temperature sensor 19 that measures the temperature of water stored in the hot water storage tank 17 that is water circulated between the hot water storage tank 17 and the heat exchanger 5, and a hot water storage tank. 17 is equipped with a hot water tank water level sensor 30 for measuring the water level of the water stored in the water 17, and the water (hot water) in the hot water tank 17 is determined based on the temperature (water temperature) measured by the hot water tank temperature sensor 19. An external drain pipe 21 having a valve 22 for draining to the outside, a water storage device supply pipe 23 having a valve 24 for supplying water (hot water) of the hot water storage tank 17 to a water storage device 25 described later, and a hot water storage tank A water supply device 28 for supplying water (for example, tap water, etc.) from the outside is connected to the inside 17. The hot water storage tank temperature sensor 19 is preferably arranged so as to measure a portion of the hot water storage tank 19 where the temperature is low. In the hot water storage tank 19 shown in FIG. It is arranged. In the cogeneration system shown in FIG. 1, the external drain pipe 21 provided with the valve 22 and the water storage device supply pipe 23 provided with the valve 24 correspond to the drainage apparatus.

  Further, the hot water storage tank 17 shown in FIG. 1 includes a notification device 20 and a control device 18 for controlling the operation of each device and each valve. The control device 18 can be shared with the control device 13 provided in the power generation unit, but it is preferable to provide the control device 18 separately in consideration of the assembly of the cogeneration system.

  In addition, as a temperature sensor for measuring the temperature of the water circulated between the hot water storage tank 17 and the heat exchanger 5, a circulation pipe temperature sensor for measuring the temperature of the water flowing through the circulation pipe 16 may be used. Is possible. In this case, the circulation pipe temperature sensor can be disposed on the upstream side of the circulation pump 15 or on the downstream side of the radiator when a radiator for reducing the temperature of the water supplied to the hot water storage tank 17 is provided. . Furthermore, the outlet water temperature sensor 14 can be shared. In the following description, as a temperature sensor for measuring the temperature of water circulated between the hot water storage tank 17 and the heat exchanger 5, a hot water storage tank temperature sensor 19 for measuring the temperature of the water stored in the hot water storage tank 17. Will be described.

  The arrows in the figure indicate the flow directions of raw fuel, oxygen-containing gas and water, and the broken lines are transmitted (transmitted) from the main signal path transmitted to the control device 18 or from the control device 18. The main signal paths are shown.

  Hereinafter, a method for operating the cogeneration system shown in FIG. 1 will be described.

  In performing steam reforming to generate fuel gas used for power generation of a fuel cell, water used in the reformer 4 is accompanied by operation of the fuel cell (cell stack 1) in the heat exchanger 5. The condensed water produced | generated by heat exchange with the waste gas produced | generated and the water which flows through the circulation piping 16 is used. The condensed water generated in the heat exchanger 5 flows through the condensed water supply pipe 6 and is supplied to the condensed water treatment device 7. The condensed water is processed by the condensed water treatment device 7 to generate pure water, and the generated pure water is supplied to the water tank 8. The water stored in the water tank 8 is supplied to the reformer 4 by the water pump 11, steam reforming is performed with the raw fuel supplied from the raw fuel supply device 2, and the generated fuel gas is used as a fuel cell. Supplied to the cell. In the fuel battery cell, power generation is performed using the fuel gas and the oxygen-containing gas supplied from the oxygen-containing gas supply device 3. Thus, water self-sustained operation can be performed by using condensed water effectively.

  In the hot water storage tank 17, the temperature of the water stored in the hot water storage tank 17 is measured by the hot water storage tank water temperature sensor 19. Here, when the temperature of the water stored in the hot water storage tank 17 exceeds a predetermined temperature, the amount of condensed water generated in the heat exchanger 5 is reduced, and sufficient water (pure water) is supplied to the reformer 4. It becomes difficult to operate the power generation unit efficiently.

  Therefore, when the temperature of the water stored in the hot water storage tank 17 exceeds a predetermined temperature, the water stored in the hot water storage tank 17 is drained and the water level stored in the hot water storage tank 17 is measured. The water stored in the hot water storage tank 17 is supplied by the water supply device 28 from the outside so that the water level measured by the hot water storage tank water level sensor 30 falls within a predetermined range. Reduce the temperature. Thereby, it can suppress that the quantity of the condensed water produced | generated with the heat exchanger 5 reduces, and can drive | operate a power generation unit efficiently.

  However, in this case, the hot water generated in the heat exchanger 5 is drained wastefully, and the operation efficiency (total efficiency) as the cogeneration system is reduced.

  Therefore, in the cogeneration system of the present invention, water (hot water) drained from the hot water storage tank 17 is automatically supplied to the water storage device 25, thereby providing a cogeneration system with improved operating efficiency (total efficiency). Can do.

  As the water storage device 25, for example, when the cogeneration system is installed in a detached house, it can be a bath or the like, and when the cogeneration system is installed in an apartment house, a bath or the like in each room. In addition, it can be a collective hot water tank for supplying hot water to each room. When the water storage device 25 is a bath, it is preferable to provide a circulation pipe for circulating water between the hot water storage tank 17 and the water storage device 25. In the cogeneration system shown in FIG. A circulation pipe 29 for circulating water between the tank 17 and the water storage device 25 is provided. In addition, a water heater or a water heater can be provided between the hot water storage tank 17 and the water storage device 25, and in this case, each device is connected by a circulation pipe 29.

  In the water storage device 25, a water storage device water level sensor 26 for measuring the water level of the water stored in the water storage device 25 and a water storage for measuring the temperature of the water stored in the water storage device 25. A water device temperature sensor 27 is preferably provided. Control based on these sensors will be described later.

  2 and 3 are flowcharts showing an example of a control flow in the cogeneration system shown in FIG. Note that the flowcharts shown in FIGS. 2 and 3 show only a series of controls in the present invention.

  During the operation of the cogeneration system, the temperature information of the water stored in the hot water storage tank 17 measured by the hot water storage tank temperature sensor 19 is transmitted to the control device 18. Here, the control device 18 operates the drainage device so as to supply the water in the hot water storage tank 17 to the water storage device 25 when the water temperature in the hot water storage tank 17 continues above the first predetermined temperature for a predetermined time or longer. Is controlled (step S1). Specifically, in the cogeneration system shown in FIG. 1, control for closing the valve 22 provided in the external drain pipe 21 and control for opening the valve 24 provided in the water storage apparatus supply pipe 23 are performed. In addition, as the valve 22 and the valve 24, generally used electromagnetic valves can be used.

  On the other hand, when the temperature of the water stored in the hot water storage tank 17 (hereinafter sometimes referred to as the water temperature of the hot water storage tank 17) has not continued above the first predetermined temperature for a predetermined time or longer, the water is stored in the hot water storage tank 17. It is determined that there is no need to drain the discharged water, and the drainage device is controlled so that the water in the hot water storage tank 17 is not drained (step S2). Specifically, in the cogeneration system shown in FIG. 1, control for closing the valve 22 provided in the external drain pipe 21 and control for closing the valve 24 provided in the water storage apparatus supply pipe 23 are performed.

  Here, the fact that the water temperature of the hot water storage tank 17 continues above the first predetermined temperature for a predetermined time or more can be appropriately set based on the rated scale of the entire cogeneration system, for example, when the rated output of the power generation unit is 700 w In, the 1st predetermined temperature can be suitably set in the range of 40-85 degreeC, and predetermined time can be suitably set between 1-60 minutes.

  Here, the control device 18 controls the operation of the drainage device so that the water in the hot water storage tank 17 is supplied to the water storage device 25 when the water temperature in the hot water storage tank continues above the first predetermined temperature for a predetermined time or longer. However, before supplying water to the water storage device 25, it is preferable to inform the user of the cogeneration system that supply of water from the hot water storage tank 17 to the water storage device 25 is started after a predetermined time has elapsed. Thereby, the user of the cogeneration system can use the hot water in the hot water storage tank 17 efficiently.

  Therefore, the control device 18 controls the operation of the notification device 20 before controlling the operation of the drainage device so as to supply the water in the hot water storage tank 17 to the water storage device 25 (step S3). In addition, as the notification device 20, for example, a display for prompting use on the operation panel of the cogeneration system, an alarm sound, an email for prompting use to a mail address registered by the user, and the like are configured. Can be set as appropriate.

  However, if the user does not use the water stored in the hot water storage tank 17 when the notification device 20 is activated and a predetermined time has elapsed, the heat in the heat exchanger 5 and the water flowing through the circulation pipe 16 is heated. The exchange is reduced, the amount of condensed water generated is reduced, and the power generation efficiency of the power generation unit (fuel cell device) may be reduced. Therefore, the control device 18 subsequently determines whether or not a predetermined time has elapsed since the notification device 20 was operated (step S4).

  When it is determined that the predetermined time has not elapsed since the notification device 20 was operated, the notification device 20 is continuously operated. On the other hand, when it is determined that the predetermined time has elapsed since the alarm device 20 was activated, the temperature of the water stored in the hot water storage tank 17 is measured by the hot water storage tank water temperature sensor 19 (step S5). .

  Here, when the temperature of the water stored in the hot water storage tank 17 falls below the first predetermined temperature (that is, when the user of the cogeneration system uses hot water), the water in the hot water storage tank 17 is drained. The control device 18 determines that it is not necessary to control the drainage device so that the water in the hot water storage tank 17 is not drained (step S2).

  On the other hand, if the temperature of the water stored in the hot water storage tank 17 continues to exceed the first predetermined temperature after a predetermined time has elapsed since the notification device 20 was activated (that is, the user of the cogeneration system When the hot water is not used), it is determined that the water in the hot water storage tank 17 needs to be drained, and the control device 18 operates the drainage device so as to supply the water in the hot water storage tank 17 to the water storage device 25. (Step S6). Specifically, in the cogeneration system shown in FIG. 1, control for closing the valve 22 provided in the external drain pipe 21 and control for opening the valve 24 provided in the water storage apparatus supply pipe 23 are performed.

  Thereby, when draining the water stored in the hot water storage tank 17, the water in the hot water storage tank 17 is automatically supplied to the water storage device 25, so that the hot water generated by heat exchange is efficiently used. And a fuel cell cogeneration system with improved operational efficiency (overall efficiency).

  In this case, the control device 18 performs control to operate the notification device 20 so as to notify the supply of the water stored in the hot water storage tank 17 to the water storage device 25 (step S7). Thereby, the user of the cogeneration system can easily recognize that the supply of water stored in the hot water storage tank 17 to the water storage device 25 has started.

  Here, in the hot water storage tank 17, a hot water storage tank water level sensor 30 is provided in the hot water storage tank 17 in order to avoid a shortage of water used by the user of the cogeneration system. The water level of the hot water storage tank 17 is controlled so as to be within a predetermined range.

  That is, the control device 18 controls the operation of the water supply device 28 so that the same amount of water discharged from the hot water storage tank 17 is supplied to the hot water storage tank 17 from the outside by controlling the operation of the drainage device 21. To do. Therefore, as the water stored in the hot water storage tank 17 is discharged, water having a low temperature is supplied to the hot water storage tank 17, so that the temperature of the water in the hot water storage tank 17 decreases.

  Therefore, the control device 18 determines whether the temperature of the water stored in the hot water storage tank 17 measured by the hot water storage tank temperature sensor 19 is lower than the second predetermined temperature set lower than the first predetermined temperature. It is determined whether or not (step S8).

  Here, when the temperature of the water stored in the hot water storage tank 17 is lower than the second predetermined temperature, the operation of the drainage device is controlled so as to stop the drainage of the water from the hot water storage tank 17 (step S9). . Specifically, in the cogeneration system shown in FIG. 1, control for closing the valve 22 provided in the external drain pipe 21 and control for closing the valve 24 provided in the water storage apparatus supply pipe 23 are performed. Thereby, hot water used by the user of the cogeneration system can be efficiently generated, and water (hot water) in a predetermined temperature range can be supplied to the user of the cogeneration system.

  On the other hand, when the temperature of the water stored in the hot water storage tank 17 is lower than the second predetermined temperature, the water stored in the hot water storage tank 17 is continuously supplied to the water storage device 25.

  Here, the second predetermined temperature can be appropriately set based on the rated scale of the entire cogeneration system or the like. For example, when the rated output of the power generation unit is 700 w, the second predetermined temperature is 35 to 45. It can be appropriately set within the range of ° C.

  By supplying the water stored in the hot water storage tank 17 to the water storage device 25 by the control as described above, the operation efficiency (overall efficiency) of the cogeneration system can be improved, but the water is stored in the water storage device 25. If the water level becomes higher than a predetermined water level, the water storage device 25 may overflow. Further, by circulating water between the hot water storage tank 17 and the water storage device 25 via the circulation pipe 29, the hot water storage tank 17 stores water without supplying water from the outside to the hot water storage tank 17. The temperature of water can be lowered. However, when the temperature of the water stored in the water storage device 25 becomes equal to or higher than a predetermined temperature, there is a possibility that a problem may occur in terms of safety.

  Here, in the cogeneration system shown in FIG. 1, the water storage device 25, the water storage device water level sensor 26 for measuring the water level stored in the water storage device 25, and the water stored in the water storage device 25. And a water storage device temperature sensor 27 for measuring the temperature of the water storage device.

  The control device 18 is configured such that the water level stored in the hot water storage tank 17 measured by the water storage device water level sensor 26 is equal to or higher than a predetermined water level, or the water storage device 25 measured by the water storage device temperature sensor 27. It is determined whether the temperature of the water stored in the tank is equal to or higher than a predetermined temperature (step S10).

  Here, water stored in the water storage device 25 measured by the water storage device water level sensor 26 is stored in the water storage device 25 measured by the water storage device temperature sensor 27 when the water level stored in the water storage device 25 is lower than a predetermined water level. When the temperature of the water to be stored is lower than the predetermined temperature, the control device 18 determines that it is not necessary to stop the water supplied to the water storage device 25, and water is continuously supplied to the water storage device 25. To control the operation of the drainage device.

  On the other hand, when the water level stored in the water storage device 25 measured by the water storage device water level sensor 26 is equal to or higher than a predetermined water level, or stored in the water storage device 25 measured by the water storage device temperature sensor 27. When the temperature of the water is equal to or higher than the predetermined temperature, the control device 18 determines that it is necessary to stop the water supplied to the water storage device 25 and drains the water drained from the hot water storage tank 17 to the outside. Thus, the operation of the drainage device is controlled (step S11). Specifically, in the cogeneration system shown in FIG. 1, control for opening the valve 22 provided in the external drain pipe 21 and control for closing the valve 24 provided in the water storage apparatus supply pipe 23 are performed.

  Thereby, while improving operational efficiency (overall efficiency), it can control that water overflows from the water storage device 25, and the temperature of the water stored in the water storage device 25 can be within a predetermined temperature range. , Can improve safety.

  In addition, the predetermined water level in the water storage device 25 can be a water level at which water does not overflow from the water storage device 25, and the predetermined temperature in the water storage device 25 is the safety in the water storage device 25. In consideration, for example, the temperature can be appropriately set within a range of 35 ° C to 45 ° C.

  Here, even when the control device 18 controls the drainage device so as to drain the water stored in the hot water storage tank 17 to the outside, the water stored in the hot water storage tank 17 measured by the hot water storage tank temperature sensor 19 is also used. It is determined whether or not the temperature is lower than a second predetermined temperature (step S12).

  Here, when the temperature of the water stored in the hot water storage tank 17 is lower than the second predetermined temperature, the operation of the drainage device is controlled so as to stop the drainage of the water from the hot water storage tank 17 (step S9). ). Thereby, hot water used by the user of the cogeneration system can be efficiently generated, and water (hot water) in a predetermined temperature range can be supplied to the user of the cogeneration system.

  On the other hand, when the temperature of the water stored in the hot water storage tank 17 is lower than the second predetermined temperature, the water stored in the hot water storage tank 17 is continuously discharged to the outside.

  FIG. 4 is a configuration diagram showing another example of the configuration of the fuel cell cogeneration system of the present invention.

  The cogeneration system shown in FIG. 4 includes an external drain pipe 21 having a valve 22 for draining the water in the hot water storage tank 17 to the outside, and a valve 24 for supplying the water in the hot water storage tank 17 to the water storage device 25. The fuel cell cogeneration system shown in FIG. 1 is the same as the fuel cell cogeneration system except that a part of the water storage device supply pipe 23 is shared. In the fuel cell cogeneration system shown in FIG. 4, a part of the piping can be reduced, and the installation work and the installation cost can be reduced.

  FIG. 5 is a block diagram showing still another example of the configuration of the fuel cell cogeneration system of the present invention.

  In the cogeneration system shown in FIG. 5, the external drain pipe 21 provided with the valve 22 for draining the water of the hot water storage tank 17 to the outside, and the water storage device 25 for the water of the hot water storage tank 17 shown in FIGS. In order to drain the water in the hot water storage tank 17 and the drain pipe 31 provided with the valve 32 for draining the water in the hot water storage tank 17 instead of the water storage device supply pipe 23 provided with the valve 24 for supplying to the outside. The three-way valve 35 is connected to the external drainage pipe 34 and a water storage device supply pipe 33 for supplying water from the hot water storage tank 17 to the water storage device 25. In the cogeneration system shown in FIG. 5, the drain pipe 31 including the valve 32, the external drain pipe 34, the water storage device supply pipe 33, and the three-way valve 35 correspond to the drainage device.

  Even in the cogeneration system having such a configuration, it is possible to easily control whether the water in the hot water storage tank 17 is drained to the outside, supplied to the water storage device 25, or the drainage from the hot water storage tank 17 is stopped.

  Specifically, for example, when the water stored in the hot water storage tank 17 is drained to the outside, the control device 18 controls to open the valve 32 and the water flowing through the drain pipe 31 flows to the external drain pipe 34. Thus, the three-way valve 35 is controlled. When water stored in the hot water storage tank 17 is supplied to the water storage device 25, the three-way valve is controlled so that the valve 32 is controlled to open and the water flowing through the drain pipe 31 flows to the water storage device supply pipe 33. 35 is controlled. Further, when the drainage from the hot water storage tank 17 is stopped, the valve 32 is controlled to be closed.

  With the configuration as described above, a fuel cell cogeneration system with improved operating efficiency (total efficiency) can be obtained.

  Although the present invention has been described in detail above, the present invention is not limited to the above-described embodiments, and various modifications and improvements can be made without departing from the scope of the present invention. .

  In the above description, the case where water is supplied to one water storage device 25 has been described as an example. However, water is supplied to a plurality of water storage devices 25 when the water in the hot water storage tank 17 is drained. You can also In this case, various sensors can be appropriately disposed, and the drainage device can be controlled based on values measured by the various sensors.

  Further, when a circulating pipe temperature sensor for measuring the temperature of water flowing through the circulation pipe 16 is used as a temperature sensor for measuring the temperature of the water circulated between the hot water storage tank 17 and the heat exchanger 5. In the flowcharts shown in FIGS. 2 and 3, “the water temperature of the hot water storage tank 17” is preferably changed to “the water temperature measured by the circulation pipe temperature sensor”.

1: Fuel cell stack 5: Heat exchanger 16, 29: Circulation piping 17: Hot water storage tank 18: Control device 19: Hot water storage tank water temperature sensor 20: Notification device 25: Water storage device 26: Water storage device water level sensor 27: Storage Water device water temperature sensor

Claims (8)

A fuel cell device comprising a fuel cell and a heat exchanger for exchanging heat between the exhaust gas from the fuel cell and water; and
A hot water storage tank for storing the water after heat exchange,
A circulation pipe for circulating water between the heat exchanger and the hot water storage tank;
A water storage device for storing water in the hot water storage tank;
And temperature sensors for measuring the temperature of the hot water storage and drainage device for draining water water external or the water storage device to the tank, before Symbol water is water in the hot water storage tank,
When the temperature of the water is measured by pre-Symbol temperature sensor is measured at a first predetermined temperature or higher continuously for a predetermined time, the draining said is water in the hot water storage tank water to be supplied to the water storage device A control device for controlling the operation of the device;
A fuel cell cogeneration system comprising:   Comprising a notification device, wherein the control device operates the notification device when the temperature of the water measured by the temperature sensor is measured at a first predetermined temperature or higher continuously for a predetermined time, and When the temperature of the water measured by the temperature sensor is continuously measured at a first predetermined temperature or higher after a predetermined time has elapsed since the notification device was activated, the water stored in the hot water storage tank is The fuel cell cogeneration system according to claim 1, wherein the operation of the drainage device is controlled so as to be supplied to a water storage device.   The said control apparatus performs control which operates the said alerting | reporting apparatus, when controlling operation | movement of the said drainage device so that the water stored by the said hot water storage tank may be supplied to the said water storage apparatus. 2. The fuel cell cogeneration system according to 2.   The drainage device includes an external drain pipe provided with a valve for draining the water of the hot water storage tank to the outside, and a water storage device supply pipe provided with a valve for supplying the water of the hot water storage tank to the water storage device. The fuel cell cogeneration system according to any one of claims 1 to 3, wherein the fuel cell cogeneration system is provided.   The drainage device includes a drain pipe provided with a valve for draining water from the hot water storage tank, an external drain pipe for draining water from the hot water storage tank to the outside, and water from the hot water storage tank to the water storage device. A water storage device supply pipe for supply is provided, and the drainage pipe, the external drainage pipe, and the water storage device supply pipe are connected by a three-way valve. Item 4. The fuel cell cogeneration system according to any one of Items 3 above.   While having a water storage device water level sensor for measuring the water level of the water storage device, the control device has a water level of the water storage device equal to or higher than a predetermined water level based on information from the water storage device water level sensor. In this case, the supply of water from the hot water storage tank to the water storage device is stopped, and the operation of the drainage device is controlled so as to drain the water stored in the hot water storage tank to the outside. The fuel cell cogeneration system according to claim 4 or 5.   The water storage device temperature sensor for measuring the temperature of the water stored in the water storage device is provided, and the control device is a temperature of water stored in the water storage device measured by the water storage device temperature sensor. 6. The fuel according to claim 4, wherein the operation of the drainage device is controlled so that the water stored in the hot water storage tank is drained to the outside when the temperature becomes equal to or higher than a predetermined temperature. Battery cogeneration system.   A water supply device for supplying water to the hot water storage tank; and a hot water storage tank water level sensor for measuring a water level of the hot water storage tank, wherein the control device is measured by the hot water storage tank water level sensor. The water level measured by the temperature sensor is set to be lower than the first predetermined temperature, while controlling the operations of the drainage device and the water supply device so that the water level is within a predetermined range. The operation of the drainage device is controlled so that drainage of water from the hot water storage tank is stopped when the temperature becomes lower than a second predetermined temperature. The fuel cell cogeneration system described in 1.

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