JP2005056836A - Fuel cell co-generation system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell co-generation system preventing hot water from getting short capable of improving convenience. <P>SOLUTION: The co-generation system comprises a fuel cell 1; a cooling system for the fuel cell 1; an internal heat-conveyance medium heater 100; a heat utilizing part 16 for storing the heat recovered through the cooling system so as to utilize the same; a detection means 101A-101C for detecting the amount of heat remaining in the utilizing part 16; and a control device 201. The control device 201 determines whether the amount of the heat remaining in the utilizing part 16 is enough for raising the temperature of the fuel cell 1 up to its operation temperature or not, and depending on the result, raises the temperature of the fuel cell 1 up to operation temperature by supplying the remaining heat through the cooling system and/or by heating the cooling water in the cooling system by the internal heat-conveyance medium heater 100. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a fuel cell cogeneration system.

  Conventional fuel cell cogeneration systems include the following (see, for example, Patent Document 1).

FIG. 16 is a block diagram showing the configuration of this conventional fuel cell cogeneration system.
In FIG. 16, this fuel cell cogeneration system includes a fuel cell 1 that generates power using a fuel gas and an oxidant gas, and a fuel processing apparatus that generates fuel gas by steam reforming and carbon monoxide conversion of the raw material fuel. 2, a fuel-side humidifier 5 that humidifies the fuel gas supplied to the fuel cell 1, an air supply device 6 that supplies oxidant air to the fuel cell 1, and an oxidation-side humidifier 7 that humidifies the supply air. I have.

In addition, this fuel cell cogeneration system sends a cooling pipe 8 for adjusting the temperature of the fuel cell 1 by sending antifreeze or the like to the fuel cell 1, a pump 9 for circulating cooling water, and heat generated in the fuel cell 1 from the outside. A heat exchanger 12 that exchanges heat with a heat transport medium (city water, etc.), and stores the heat in the heat utilization means 16 such as a hot water storage tank that recovers exhaust heat of the fuel cell by the external heat transport medium that has been heat-exchanged; In addition, the exhaust heat transport control means 17 transports the external heat transport medium in the direction opposite to that at the time of exhaust heat recovery when the fuel cell is started, and the exhaust heat recovered by the heat utilization means 16 is passed through the heat exchange means 12 to the fuel cell. 1 is configured to transport exhaust heat.
JP 2002-042841 A (page 3-6, FIG. 1)

  By the way, as in the above-described conventional fuel cell cogeneration system, the use of hot water stored in the heat utilization means as heat for heating the fuel cell 1 at the time of activation shortens the activation time and increases the energy utilization efficiency. Is the best.

  However, since the user generally uses hot water regardless of the amount of remaining hot water in the heat utilization means, when the amount of remaining hot water in the heat utilization means is small, the remaining hot water in the heat utilization means disappears due to the use of hot water, so There was a case. In particular, in the case of a heat utilization means that does not have a built-in backup hot water supply device or the like for securing hot water supply in the case of running out of hot water, the hot water supply cannot be used when the water runs out, which is extremely inconvenient. There was a problem.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a fuel cell cogeneration system that can improve the convenience by preventing running out of hot water.

  In order to solve the above problems, a fuel cell cogeneration system according to the present invention includes a fuel cell, a cooling system for circulating the internal heat transport medium so that the fuel cell and the internal heat transport medium exchange heat, and the internal heat. An internal heat transport medium heater that heats the transport medium, a heat utilization unit that stores the external heat transport medium so that a user can use it, and the internal heat transport medium and the external heat transport medium of the cooling system exchange heat. A waste heat utilization system that circulates the external heat transport medium through the heat utilization section, a residual heat amount detection means that detects a residual heat amount of the heat utilization section, and a control device, wherein the control device includes the fuel At the time of starting the battery, the detected residual heat amount of the heat utilization unit is equal to or greater than a threshold heat amount that is equal to or greater than the fuel cell temperature increase amount, which is the amount of heat necessary for increasing the temperature of the fuel cell to the operating temperature. A first temperature raising operation for raising the temperature of the fuel cell by transferring the residual heat quantity of the heat utilization part to the internal heat transport medium by heat exchange based on the judgment result and the internal heat transport A distribution to a second temperature raising operation for heating the internal heat transport medium by a medium heater to raise the temperature of the fuel cell is determined, and the first temperature raising operation and / or the second temperature raising operation The fuel cell is heated to the operating temperature.

  When the residual heat quantity is equal to or greater than the threshold heat quantity, the control device mainly raises the temperature of the fuel cell to the operating temperature in the first temperature raising operation, and the residual heat quantity is less than the threshold heat quantity. In this case, the fuel cell may be heated to the operating temperature mainly in the second temperature raising operation.

  The fuel cell cogeneration system includes means for detecting a temperature of an external heat transport medium stored in the heat utilization unit, and the control device, when the remaining heat amount is less than the threshold heat amount, In the case where the temperature of the fuel cell is raised to the operation temperature mainly in the temperature raising operation of No. 2 and the residual heat quantity is not less than the threshold heat quantity, the detected temperature of the external heat transport medium is not less than the operation temperature. And determining the distribution between the first temperature raising operation and the second temperature raising operation on the basis of the determination result, the first temperature raising operation and / or the second temperature raising operation. The fuel cell may be heated to the operating temperature by operation.

  When the temperature of the external heat transport medium is equal to or higher than the operating temperature, the control device mainly raises the temperature of the fuel cell to the operating temperature in the first temperature raising operation, When the temperature is lower than the operating temperature, the fuel cell may be heated to the operating temperature mainly by the second temperature raising operation.

  The fuel cell cogeneration system includes means for detecting an air temperature outside the fuel cell, and the control device, when the temperature of the external heat transport medium is equal to or higher than the operating temperature, When the temperature of the external heat transport medium is lower than the operation temperature, the temperature of the external heat transport medium is equal to or higher than the detected external air temperature. And determining the distribution between the first temperature raising operation and the second temperature raising operation based on the determination result, and the first temperature raising operation and / or the second temperature raising operation. The fuel cell may be heated to the operating temperature by a temperature raising operation.

  When the temperature of the external heat transport medium is equal to or higher than the detected external temperature, the control device combines the first temperature raising operation and the second temperature raising operation to combine the fuel cell. When the temperature is raised to the operating temperature and the temperature of the external heat transport medium is lower than the detected outside air temperature, the fuel cell is raised to the operating temperature mainly in the second temperature raising operation. May be.

  When the threshold heat amount is composed of the fuel cell temperature increase heat amount and a predetermined heat amount, and the control device is configured to mainly control the fuel cell in the first temperature increase operation when the remaining heat amount is equal to or greater than the threshold heat amount. When the temperature is raised to the operating temperature and the residual heat quantity is less than the threshold heat quantity, the fuel cell may be raised mainly to the operating temperature mainly in the second temperature raising operation.

  The predetermined amount of heat may be an amount of heat used during a start-up time period that is assumed to be used by a user during a start-up time period extending from a start time of the fuel cell to a predetermined time.

  The fuel cell cogeneration system includes means for detecting the amount of heat used due to the use of an external heat transport medium stored in the heat utilization unit, means for acquiring time, and the time when the detected amount of heat used is acquired. Storage means for storing, and the control device may calculate the use heat amount for the startup time zone based on the use heat amount stored together with the time.

  The control device may calculate the start-up time zone use heat amount so as to take an average value over a predetermined period.

  The predetermined heat amount may be a fixed amount and a correction amount, and the control device may change the correction amount based on the calculated startup time zone use heat amount.

The fuel cell cogeneration system may include means for detecting a temperature outside the fuel cell, and the control device may change the predetermined amount of heat based on the detected outside temperature.
The fuel cell cogeneration system includes means for detecting the temperature of the external heat transport medium to be used, and the control device has a frequency at which the detected temperature of the external heat transport medium to be used becomes a predetermined value or less. The predetermined heat quantity may be changed according to the above.

  The external heat transport medium may be water, and the heat utilization unit may be a hot water storage tank.

  The hot water storage tank may be composed of a stacked boiling type.

  When the residual heat amount is equal to or higher than the fuel cell temperature increase amount, the control device raises the fuel cell temperature to the operating temperature only by the first temperature increase operation, and the residual heat amount is the fuel cell amount. If it is less than the temperature rise, the fuel cell may be raised to the operating temperature only by the second temperature raising operation.

  The present invention has a configuration as described above, and in the fuel cell cogeneration system, there is an effect that it is possible to prevent the hot water from running out and improve convenience. As a result, the fuel cell cogeneration system is an extremely useful device especially when the hot water storage tank does not have a built-in hot water heater for backup when the hot water tank runs out.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1)
1 is a block diagram showing a configuration of a fuel cell cogeneration system according to Embodiment 1 of the present invention.

  In FIG. 1, the configuration of the fuel cell cogeneration system is roughly divided into a hardware configuration and a control system configuration.

  First, the hardware configuration will be described. The fuel cell cogeneration system includes a fuel cell 1 that generates power using fuel gas and an oxidant gas, a fuel processing device 2 that generates fuel gas from raw material and water, and supplies the fuel gas to the fuel cell 1, A fuel-side humidifier 5 that humidifies the fuel gas supplied to the fuel cell 1 on the way, an air supply device 6 that supplies air as an oxidant to the fuel cell 1, and air supplied to the fuel cell 1 An oxidation side humidifier 7 that humidifies in the middle is provided. The fuel processing apparatus 2 includes a reformer 3 that generates a fuel gas by steam reforming a raw material, and a transformer 4 that converts the generated fuel gas.

  The fuel cell cogeneration system includes a cooling system that cools the fuel cell 1 and an exhaust heat utilization system that uses exhaust heat recovered by the cooling system.

  This cooling system is a cooling water in which both ends thereof are connected to an inlet and an outlet of a cooling water flow path (hereinafter referred to as an internal flow path) 1a of the fuel cell 1 and a cooling water (an antifreeze liquid in this case) flows as an internal heat transport medium. The piping 8, the cooling water pump 9 provided in the middle of the cooling water piping 8 and circulating the cooling water, and the heat held in the cooling water piping 8 and held in the cooling water are transferred to an external heat transport medium (here, hot water ( A heat exchanger 12 for exchanging with city water)). The heat exchanger 12 is provided so that one of the pair of heat exchange channels is connected to the cooling water pipe 8.

  Further, a pipe 31 is provided so as to connect portions of the pipe 8 located on both sides of the heat exchanger 12, and a cooling water heater 100 and a flow rate adjusting valve 13 for heating the cooling water are provided in the middle of the pipe 31. It has been. Further, a flow rate adjusting valve 14 is provided in a portion of the pipe 8 between the connection portion between the pipe 8 and the pipe 31 and the heat exchanger 12. The cooling water heater 100 is composed of, for example, a resistance heating type heater, and is configured to generate heat by a current supplied from a power source (not shown) connected to the power system.

  The exhaust heat utilization system includes a hot water storage tank 16 as a heat utilization unit, a pair of pipes 15a and 15b, and a circulation direction switching means 17. As a usage form of the hot water storage tank 16, a stacked boiling system is employed here. Specifically, the hot water storage tank 16 is formed in a cylindrical shape here so that its central axis extends in the vertical direction. The upper end of the hot water storage tank 16 and the other end of the pair of heat exchange channels of the heat exchanger 12 are connected by a pipe 15a. Further, the lower end of the hot water storage tank 16 and the other other end of the pair of heat exchange channels of the heat exchanger 12 are connected by a pipe 15b. A circulation direction switching means 17 is provided in the middle of the pipe 15b.

  The circulation direction switching means 17 includes a hot water pump 20 as an external heat transport medium circulation means, a discharge side branch joint 23 and a suction side branch joint 24 connected to the discharge port and the suction port of the hot water pump 20, respectively, and piping. 15b portion of the heat exchanger 12 side, the discharge side branch joint 23, the first flow path switching valve 21 connected to the suction side branch joint 24, the portion of the pipe 15b on the hot water storage tank 16 side, the suction side branch joint 24, and a second flow path switching valve 22 connected to the discharge side branch joint 23. With this configuration, the circulation direction switching means 17 switches the first flow path switching valve 21 so that the heat exchanger side portion of the pipe 15b is connected to the suction side branch joint 24, and the second flow path switching valve 22 is connected. Is switched so that the portion of the pipe 15b on the hot water storage tank 16 side is connected to the discharge-side branch joint 24, so that hot water is taken out from the upper end of the hot water storage tank 16 and sent to the lower end of the hot water storage tank 16 (arrow B direction). And the first flow path switching valve 21 is switched so that the heat exchanger side portion of the pipe 15b is connected to the discharge side branch joint 23, and the second flow path switching valve 22 is switched to the pipe 15b. A direction in which hot water is taken out from the lower end of the hot water storage tank 16 and sent to the upper end of the hot water storage tank 16 (arrow A) by switching so that the hot water storage tank 16 side portion is connected to the suction side branch joint 24. It can be circulated countercurrent).

  The exhaust heat utilization system includes a pipe 32 for supplying city water connected to the lower end of the hot water storage tank 16, and a pipe 33 for supplying hot water stored in the hot water storage tank 16 to the user. Thus, the city water sent from the pipe 32 to the hot water storage tank 16 is warmed by the exhaust heat of the fuel cell 1, and this hot water is taken out from the pipe 33 and supplied to the user.

  Next, the configuration of the control system will be described. The fuel cell cogeneration system includes a control device 201, first to third tank temperature sensors 101A to 101C as residual heat amount detection means, a flow meter 102 as utilization heat amount detection means, and the temperature of the stack of the fuel cell 1. Is provided with a stack temperature sensor 202, a first heat exchange temperature sensor 18, and a second heat exchange temperature sensor 19. The control device 201 is composed of a computing device and includes a computing unit 105, a storage unit 104, and a time measuring unit 103. Here, a microcomputer is used as the arithmetic unit, the arithmetic unit 105 is a CPU, and the storage unit 104 is a semiconductor memory such as a ROM or a RAM.

  The first to third temperature sensors 101 </ b> A to 101 </ b> C are composed of, for example, a thermistor or a thermocouple, and are arranged so as to detect the temperature distribution in the vertical direction of the hot water storage tank 16. Here, the 1st-3rd temperature sensors 101A-101C are provided so that it may each be located in the center of each surface of the upper part 16a of the hot water storage tank 16, the intermediate part 16b, and the lower part 16c.

  Outputs (temperature detection signals) of the first to third temperature sensors 101A to 101C are input to the calculation unit 105 of the control device 201, respectively.

  The stack temperature sensor 202 is composed of, for example, a thermistor or a thermocouple, and is disposed in the stack of the fuel cell 1. The output (temperature detection signal) of the stack temperature sensor 202 is input to the calculation unit 105 of the control device 201.

  The flow meter 102 is disposed in a pipe 33 that supplies hot water to a user, and its output (flow rate detection signal) is input to the calculation unit 105 of the control device 201.

  The first and second heat exchange temperature sensors 18 and 19 are each formed of, for example, a thermistor. The first heat exchange temperature sensor 18 is arranged in the vicinity of the connection portion of the pipe 15a to the heat exchanger 12, and the second heat exchange temperature sensor 19 is in the vicinity of the connection portion of the pipe 15b to the heat exchanger 12. It is arranged. Outputs (temperature detection signals) of the first and second heat exchange temperature sensors 18 and 19 are input to the calculation unit 105 of the control device 201.

  On the other hand, the calculation unit 105 controls the on / off of the cooling water heater 100 and the operation of the circulation direction switching means 17.

  Further, although not shown in the figure, the output of a required sensor of the fuel cell cogeneration system is input to the calculation unit 105 and necessary components of the fuel cell cogeneration system are controlled by the calculation unit 105. ing. Thus, the calculation unit 105 performs calculation, processing, and the like based on each input, and outputs a control signal to each component based on this, thereby including a fuel cell cogeneration system including temperature raising means selection control described later. To control the operation.

  Next, the operation of the fuel cell cogeneration system configured as described above will be described. This operation is performed under the control of the control device 201 as described above. Note that the control device 201 itself is always operating (more accurately, after the fuel cell cogeneration system is installed).

  First, a general operation will be described. The fuel cell cogeneration system has a start mode, an operation mode, and a stop mode as operation modes. In the start mode, the fuel cell cogeneration system is smoothly and safely started by a predetermined operation. Power generation is performed in the operation mode, and in the stop mode, the fuel cell cogeneration system is smoothly and safely stopped by a predetermined operation.

  Specifically, in FIG. 1, in the operation mode, the raw material gas and water are supplied to the reformer 3, where fuel gas composed of hydrogen-rich reformed gas is generated. This fuel gas is supplied to the transformer 4, where the concentration of hydrogen gas is increased by a shift reaction, then supplied to the fuel-side humidifier 5, where it is humidified, and then the fuel electrode (not shown) of the fuel cell 1. ).

  On the other hand, air as an oxidizing gas is supplied from the air supply device 6 to the oxidation side humidifier 7 where it is humidified, and then supplied to the air electrode (not shown) of the fuel cell 1. This oxidizing gas then reacts with the fuel at the anode to generate electricity and heat.

  The fuel and oxidizing gas that have not been used for the reaction are discharged to the outside of the fuel cell 1. The generated electricity is supplied to a load or the like from an output unit (not shown).

  On the other hand, in the cooling system and the exhaust heat utilization system, in the operation mode, the flow rate adjusting valve 13 is fully closed and the flow rate adjusting valve 14 is fully opened, and the cooling water pump 9 supplies the cooling water to the internal flow path of the fuel cell 1. It circulates through 1a, the pipe 8, and the heat exchanger 12. Thereby, the heat (exhaust heat) generated in the fuel cell 1 is recovered by the cooling water, the fuel cell 1 is cooled, and the recovered heat is transmitted to the hot water storage in the heat exchanger 12.

  In the circulation direction switching means 17, the first flow path switching valve 21 is switched to connect the portion on the heat exchanger side of the pipe 15b to the discharge-side branch joint 23, and the second flow path switching valve. 22 is switched to connect a portion of the pipe 15b on the hot water storage tank 16 side to the suction side branch joint 24, and the hot water is taken out from the hot water storage pump 20 in the direction of arrow A, that is, from the lower end of the hot water storage tank 16. Circulation is performed in such a direction as to be sent to the upper end of the hot water storage tank 16. Thereby, in the heat exchanger 12, heat is transferred (recovered) from the cooling water to the hot water, and the cooling water is cooled by the hot water. The stored hot water to which heat has been transmitted in this way is heated and thereby stored in the tank 16 in such a manner that the temperature increases from the bottom to the top. The stored hot water is used (consumed) by the user in a timely manner through the pipe 33 and a hot water supply terminal such as a currant. Then, city water is supplied from the pipe 32 to the hot water storage tank 16 so as to replenish the consumed hot water storage.

  Next, the temperature raising means selection operation of the fuel cell cogeneration system characterizing the present invention will be described with reference to FIGS. 2 is a flowchart showing the temperature raising means selection operation of the fuel cell cogeneration system of FIG.

  Referring to FIGS. 1 and 2, in this temperature raising means selection operation, calculation unit 105 of control device 201 calculates a residual heat quantity Q of hot water storage tank 16 (step S1). Specifically, this is performed as follows.

  1 and 2, the temperatures of the upper portion 16a, the middle portion 16b, and the lower portion 16c of the hot water storage tank 16 are sequentially input from the first to third tank temperature sensors 101A to 101C to the calculation unit 105, respectively. The calculating part 105 calculates the residual heat quantity Q of the hot water storage tank 16 as follows. First, by multiplying the product of the volume of the upper part 16a of the hot water storage tank 16 and the temperature of the upper part 16a of the hot water storage tank 16 input from the first tank temperature sensor 101A, a residual heat quantity of the upper part 16a of the hot water storage tank 16 is obtained. Is calculated. Further, the product of the volume of the middle portion 16b of the hot water storage tank 16 and the temperature of the middle portion 16b of the hot water storage tank 16 input from the second tank temperature sensor 101B is multiplied by a predetermined coefficient to thereby reduce the remaining heat amount in the middle portion of the hot water storage tank 16. calculate. Further, the product of the volume of the lower part 16c of the hot water storage tank 16 and the temperature of the lower part 16c of the hot water storage tank 16 input from the third tank temperature sensor 101C is multiplied by a predetermined coefficient, thereby remaining heat in the lower part 16c of the hot water storage tank 16 Is calculated. Then, the residual heat quantity of each part of the hot water storage tank 16 is summed to obtain the residual heat quantity Q of the hot water storage tank 16. In addition, you may measure the volume of each part 16a-16c of the hot water storage tank 16 by experiment.

  Next, the calculation unit 105 calculates the amount of heat (hereinafter referred to as fuel cell temperature increase amount) QF required to raise the temperature of the fuel cell 1 to its operating temperature (step S2). Specifically, a stack temperature detection signal is input from the stack temperature sensor 202 to the calculation unit 105, and the calculation unit 105 converts the temperature detection signal to obtain a stick temperature. On the other hand, the storage unit 104 of the control device 201 stores the operating temperature of the fuel cell 1 and the heat capacity of the stack, and the calculation unit 105 reads out these from the storage unit 104 and determines the operating temperature of the fuel cell 1. The fuel cell heating heat quantity QF is calculated by multiplying the difference between the input stack temperature and the stack heat capacity. In the case of simplifying the calculation, the fuel cell heating heat amount QF may be set as a fixed value without considering the temperature of the stack, and stored in the storage unit 104 and appropriately read out.

  Next, the calculating part 105 determines whether the fuel cell 1 is at the time of starting (step S3). Here, as described above, the control device 105 is always operating (ON), and it is the portion excluding the control device 201 of this fuel cell cogeneration system that is activated and stopped. Therefore, “when the fuel cell 1 is activated” refers to a time when a control signal for starting the activation mode is output from the control device 201 to the fuel cell 1. However, the “time” to be determined in step S3 need not be limited to “startup”, and an appropriate time point in the start-up mode can be selected according to the design.

  If it is not the time of startup, the process returns to step S1. On the other hand, if it is during startup, it is determined whether or not the residual heat quantity Q of the hot water storage tank 16 is equal to or higher than the fuel cell temperature rise heat quantity QF (threshold heat quantity, hereinafter referred to as the temperature rise means selection threshold value QLT) (step S4).

  If the residual heat quantity Q in the hot water storage tank 16 is equal to or higher than the fuel cell temperature rise QF, the fuel cell 1 is heated up by this residual heat quantity Q (step S5), and the residual heat quantity Q in the hot water storage tank 16 is increased. If the temperature is lower than QF, the temperature of the fuel cell 1 is raised by the cooling water heater 100 (step S6).

  Hereinafter, these temperature raising operations will be specifically described. First, when the temperature of the fuel cell 1 is raised by the residual heat quantity Q in the hot water storage tank 16, the flow rate adjustment valve 14 of the cooling system is fully opened, the flow rate adjustment valve 13 is fully closed, and the cooling water pump 9 is operated. . In the circulation direction switching means 17, the first flow path switching valve 21 is switched to connect the heat exchanger side portion of the pipe 15 b to the suction side branch joint 24, and the second flow path switching valve. 22 is switched to connect the portion of the pipe 15b on the hot water storage tank 16 side to the discharge-side branch joint 23, and the hot water storage water pump 20 is operated. Thus, the hot water is circulated and stored in the hot water storage tank 16 by the hot water storage pump 20 in the direction of arrow B, that is, in the direction of being taken out from the upper end of the hot water storage tank 16 and sent to the lower end of the hot water storage tank 16. Heat is transferred from the hot water to the cooling water in the heat exchanger 12. Then, the cooling water to which this heat has been transmitted flows through the internal flow path 1a of the fuel cell 1, and the temperature of the fuel cell 1 is raised by the heat.

  On the other hand, when the temperature of the fuel cell 1 is raised by the cooling water heater 100, the flow rate adjustment valve 14 of the cooling system is fully closed, the flow rate adjustment valve 13 is fully opened, and the cooling water pump 9 is operated. On the other hand, the hot water storage pump 20 is stopped in the circulation direction switching means 17. Thereby, the cooling water heated by the cooling water heater 100 flows through the internal flow path 1a of the fuel cell 1, and the temperature of the fuel cell 1 is increased.

  As described above, in the present embodiment, the hot water storage tank 16 remains without using the cooling water heater 100 only when the residual heat quantity Q of the hot water storage tank 16 is equal to or greater than the heat quantity QF necessary for raising the temperature of the fuel cell 1. Since the temperature of the fuel cell 1 is increased by the amount of heat Q, it is possible to prevent running out of hot water due to the temperature increase of the fuel cell 1.

[Modification 1]
Next, a first modification of the present embodiment will be described.

  FIG. 3 is a flowchart showing the temperature raising means selection operation of the fuel cell cogeneration system in this modification.

  In this modification, the temperature raising means selection operation by the control of the control device 201 is different from the temperature raising means selection operation of FIG. 2, and the other points are the same as the configurations of FIGS. Specifically, as shown in FIGS. 1 and 3, the calculation unit 105 of the control device 201 calculates the fuel cell heating temperature QF in step S <b> 2 and then obtains the hot water temperature TW and the fuel cell operating temperature TO. To do. That is, the calculation unit 105 converts the temperature detection signal of the upper part of the hot water tank 16 input from the first tank temperature sensor 101A into a temperature using a predetermined conversion formula, and uses this temperature as the hot water temperature TW. . In addition, the operation temperature TO of the fuel cell 1 is stored in advance in the storage unit 104 of the control device 201, and the calculation unit 105 reads out the fuel cell operation temperature TO from the storage unit 104 and acquires it.

  Then, when it is determined in step S4 that the residual heat quantity Q is equal to or higher than the fuel cell temperature increase heat quantity QF, the calculation unit 105 determines whether or not the stored hot water temperature TW is equal to or higher than the fuel cell operating temperature TO. (Step S12). When the hot water temperature TW is equal to or higher than the fuel cell operating temperature TO, the temperature of the fuel cell 1 is raised by the residual heat quantity Q. When the hot water temperature TW is lower than the fuel cell operating temperature TO, the fuel cell 1 is cooled by the cooling water 100. Raise the temperature. The other points are the same as the temperature raising means selection operation of FIG.

  Thereby, the temperature of the fuel cell 1 can be reliably raised to the predetermined operating temperature TO.

[Modification 2]
Next, a second modification of the present embodiment will be described.

  FIG. 4 is a flowchart showing the temperature raising means selection operation of the fuel cell cogeneration system according to the present modification, FIG. 5 is a graph showing the daily change in the remaining heat amount, and FIG. 6 is the daily change in the amount of heat used by the user. It is a graph which shows an example of a time change.

  In this modification, the temperature raising means selection operation by the control of the control device 201 is different from the temperature raising means selection operation of FIG. 2, and the other points are the same as the configurations of FIGS. Specifically, as shown in FIGS. 1 and 4, the calculation unit 105 of the control device 201 calculates the residual heat quantity Q by the above-described method in step S <b> 1, but here, the calculated residual heat quantity Q is calculated. It is stored in the storage unit 104 together with the time input from the time measuring unit 103. This residual heat quantity Q is stored as a daily residual heat quantity in units of one day. This data is stored for a predetermined number of days from the present, and is sequentially deleted (overwritten) when the predetermined number of days elapses.

  Next, the computing unit 105 computes the fuel cell heating heat quantity QF in step S2, and then computes the use heat quantity E in step S13. That is, the flow rate of the hot water used through the pipe 33 (hereinafter referred to as hot water supply) is sequentially input from the flow meter 102 to the calculation unit 105 of the control device 201. Further, the temperature of the upper portion 16a of the hot water storage tank 16 is sequentially input to the calculation unit 105 from the first tank temperature sensor 101A. The calculation unit 105 multiplies the product of the flow rate of hot water input from the flow meter 102 and the temperature of the upper part 16a of the hot water storage tank 16 input from the first tank temperature sensor 101A by a predetermined coefficient. The amount of heat E used is calculated, and this amount of heat E is stored in the storage unit 104 together with the time input from the time measuring unit 103. This amount of used heat E is stored in units of one day as the amount of heat used by the user for one day. This data is stored for a predetermined number of days from the present, and is sequentially deleted (overwritten) when the predetermined number of days elapses.

  Next, the calculation unit 105 determines whether or not the fuel cell 1 is activated (step S3), and repeats steps S1, 2, 13, and 3 until it is activated. When activated, it is determined whether or not the residual heat quantity Q of the hot water storage tank 16 is equal to or greater than the total value of the fuel cell temperature rise heat quantity QF and the use time period use heat quantity ESA of the use heat quantity E (step S4). .

  If the residual heat quantity Q is equal to or greater than the total value of the fuel cell temperature rise heat quantity QF and the startup time zone use heat quantity ESA, the temperature of the fuel cell 1 is raised by the residual heat quantity Q (step S5), and the residual heat quantity Q is the fuel cell. If it is less than the total value of the temperature rise heat quantity QF and the startup time zone use heat quantity ESA, the temperature of the fuel cell 1 is raised by the cooling water heater 100 (step S5).

  Next, the temperature raising means selection determination in step S4 will be described in detail. The calculation unit 105 repeats the operations of steps S1, 2, 13, and 4 to 6, and the storage unit 104 stores the daily change in the amount of heat used and the change in the amount of heat remaining in the day over time. .

  The amount of heat used (substantially meaning the amount of hot water supply used here) E changes over time as shown by a solid line in FIG. In FIG. 6, heat is used in the time zone from 18:00 to 12:00 and from 18:00 to 24:00 from evening to night, and the amount of heat used ES1 is particularly large in the time zone from 18:00 to 24:00. In this case, the remaining heat quantity Q of the hot water storage tank 16 changes with time as shown by a solid line in FIG. 5, and finally becomes a heat quantity of Q1 around the end of the day (24:00).

  In this modification, the fuel cell cogeneration system is set to be automatically started and stopped, starts at about 6:00 in the morning (time t1), and stops at about 24:00 at night. Further, in this modification, the amount of heat E used as a criterion for selecting the temperature raising means is determined in consideration of the life pattern of the user, and specifically, the activation time zone (here, period tA (time: The amount of heat used ES2 in t1 to t2)) is used as the amount of heat that serves as this criterion (hereinafter referred to as start-up time zone used heat amount ESA). Here, in this specification, “start-up time zone” means “a time zone from the start of the fuel cell cogeneration system until the heat use started at the same time or thereafter is stopped for a predetermined time or more”. Say. As this predetermined time, 60 minutes is used in this modification. However, since the frequency of heat use varies depending on the heat use form of the user or the number of users, the “start-up time zone” is not limited to this predetermined time (60 minutes). For example, when the heat use frequency is high or the number of users is large, it is necessary to lengthen the predetermined time. Conversely, when the heat use frequency is low or the number of users is small, it is necessary to shorten the predetermined time. In this way, it is possible to define a “start-up time zone” that matches the actual usage.

  Therefore, when the temporal change in the residual heat quantity Q and the used heat quantity E on a certain day is as shown by the solid lines in FIGS. 5 and 6, the calculation unit 105 performs step S4 at the time of startup (time T1) on the next day. , It is determined whether or not Q1 as the remaining heat quantity Q is equal to or greater than the total value of the used heat quantity ES2 as the startup time zone used heat quantity ESA and the fuel cell heating heat quantity QF. Here, it is assumed that the residual heat quantity Q1 is smaller than the total value of the use heat quantity ES2 and the fuel cell heating heat quantity QF. In this case, the arithmetic unit 105 determines that the remaining heat quantity Q is less than the total value of the fuel cell heating heat quantity QF and the startup time zone use heat quantity ESA, and raises the temperature of the fuel cell 1 by the cooling water heater 100. (Step S6). As a result, when the fuel cell 1 is started up, it is possible to prevent the hot water from running out when a certain heat of use (ES2) is expected due to the life pattern. In FIG. 5, the decrease amount QL1 of the residual heat quantity Q during the period tA corresponds to the total value of the use heat quantity ES2 and the fuel cell temperature rise heat quantity QF.

  On the other hand, when the utilization heat quantity ES3 in the time zone from 18:00 to 24:00 on the day is small as shown by the one-dot chain line in FIG. 6, the remaining heat quantity Q of the hot water storage tank 16 is as shown by the one-dot chain line in FIG. Eventually, the amount of heat becomes Q2. Here, it is assumed that the remaining heat quantity Q2 is larger than the total value of the use heat quantity ES3 and the fuel cell heating heat quantity QF. In this case, at the start of the next morning, the calculation unit 105 determines in step 4 that the remaining heat amount Q is equal to or greater than the total value of the fuel cell heating heat amount QF and the starting time zone use heat amount ESA. The fuel cell 1 is activated. Thereby, in the fuel cell cogeneration system, the temperature of the fuel cell 1 is raised after ensuring the amount of heat used ES2 in the period tA. As a result, in the period tA, there is a decrease QL2 in the residual heat quantity Q corresponding to the total value of the use heat quantity ES2 due to hot water supply and the fuel cell heating heat quantity QF, but the hot water does not run out at the end of use of hot water supply t2.

  As described above, according to the present modification, the exhaust heat recovered without causing shortage in the use of the hot water supply of the user when the fuel cell 1 is started according to the remaining heat quantity Q stored in the hot water storage tank 16 during operation. Can be used effectively.

  In the above description, the use heat amount ES2 in the start time zone tA of the previous day is used as the start time zone use heat amount ESA. However, when the configuration is simplified, the start time zone use heat amount ESA may be a fixed value. .

[Modification 3]
Next, a third modification of the present embodiment will be described. In the second modification, the threshold value QLT in the temperature raising means selection determination is set in consideration of the life pattern of the user. Specifically, the use heat amount ES2 in the start time zone tA of the previous day is set as the start time zone use heat amount ESA. It is used. However, since the amount of heat used ES2 varies depending on the day, particularly when the variation between the current day and the previous day is large, it may not be possible to prevent hot water from being appropriately prevented. The present modification is intended to solve this problem.

  FIG. 7 is a flowchart showing the temperature raising means selection operation of the fuel cell cogeneration system in this modification.

  This modification differs from modification 2 in the following points. That is, as shown in FIG. 7, when it is determined in step S3 that it is not at the start-up time, the calculation unit 105 determines a predetermined start-up time zone use heat amount ESA (here, the use heat amount ES2 in the period tA that is the start-up time zone). An average value ESAA for each period is calculated, and the calculated average value of start-up time zone use heat amount ESA (hereinafter referred to as average start-up time zone use heat amount) ESAA is stored in the storage unit 104. As the predetermined period, for example, one week, one month or season is used. This average startup time zone use heat quantity ESAA is updated every period longer than the predetermined period.

  Then, in step S4, it is determined whether or not the remaining heat quantity Q is equal to or greater than the total value of the fuel cell heating temperature quantity QF and the average startup time zone use heat quantity ESAA. Other points are the same as in the second modification.

  According to this modification, since the average value ESAA is used as the startup time zone use heat amount ESA considered in the temperature raising means selection threshold value OLT, the fluctuation in the temperature raising means selection threshold value QLT is reduced, and It is possible to reduce hot water shortage when there is a large fluctuation from the previous day.

(Embodiment 2)
In the second and third modifications of the first embodiment, the temperature raising means selection threshold value OLT is set in consideration of the user's life pattern. However, the user's life pattern fluctuates by being affected by seasonal changes. For example, in general, the amount of heat used for hot water supply or heating in the morning increases as the outside air temperature decreases. Embodiment 2 of the present invention shows an example in which the temperature raising means selection threshold value OLT is set in anticipation of a change in the amount of heat used in the startup time zone due to this seasonal change.

  FIG. 8 is a block diagram showing a configuration of a fuel cell cogeneration system according to Embodiment 2 of the present invention. 8, parts that are the same as or correspond to those in FIG. 1 are given the same reference numerals, and descriptions thereof are omitted.

  In the present embodiment, an outside air temperature sensor 106 that detects the outside air temperature is disposed at an appropriate place, and a temperature detection signal of the outside air temperature sensor 106 is input to the calculation unit 105 of the control device 201. Then, the calculation unit 105 selects the temperature raising means in consideration of the detected outside air temperature. A temperature sensor such as a thermistor is used as the outside air temperature sensor 106. The other points are the same as in the first embodiment (configuration in FIGS. 1 and 2).

  Next, the operation of the fuel cell cogeneration system configured as described above will be described. FIG. 9 is a flowchart showing the temperature raising means selection operation of the fuel cell cogeneration system of FIG. 9, steps that are the same as or correspond to those in FIG. 4 are given the same reference numerals, and descriptions thereof are omitted.

  8 and 9, in the present embodiment, the calculation unit 105 calculates the fuel cell temperature rise amount QF in step S2, and then calculates the correction amount QH based on the outside air temperature in step S15. Then, in step S4, it is determined whether or not the remaining heat quantity Q is equal to or greater than the total value of the fuel cell heating heat quantity QF, the reference startup time zone use heat quantity QA, and the correction quantity QH. The other points are the same as the configurations of FIGS. 1 and 2 of the first embodiment.

  Hereinafter, differences from the first embodiment will be described in detail.

  FIG. 10 is a graph showing a change in start-up time zone use heat amount ESA (hereinafter referred to as an outside air temperature-start-up time zone use heat amount characteristic) with respect to a change in outside air temperature TA.

  In general, the amount of heat used in the startup time zone tA increases as the outside air temperature decreases. In the present embodiment, the outside air temperature-starting time zone use heat quantity characteristic is stored in advance in the storage unit 104 of the control device 201. The heat capacity characteristic of the outside air temperature-start-up time zone is obtained here through experiments, simulations, and the like. FIG. 10 shows an example of the outside air temperature-startup time zone use heat quantity characteristic. And the memory | storage part 104 memorize | stores the reference | standard starting time zone use calorie | heat amount QA for setting the temperature rising means selection threshold value QLT using this external temperature-starting time zone calorie | heat amount characteristic. This reference start time zone use heat quantity QA may be set to an arbitrary value, but here the start time zone use heat quantity corresponding to the standard outside temperature in this outside temperature-startup time zone use heat quantity characteristic is set. Yes.

  In step S15, the operation unit 105 converts the outside air temperature detection signal input from the outside air temperature sensor 106 into a temperature to obtain the outside air temperature TA, and also uses the outside air temperature-startup time zone heat quantity characteristic and the reference from the storage unit 104. Reads the amount of heat QA used during the startup time. Then, the difference ΔESA between the startup time zone use heat amount ESA (ESA1 in FIG. 10) corresponding to the outside temperature TA (TA1 in FIG. 10) on the outside temperature-startup time zone use heat quantity characteristic and the reference startup time zone use heat amount QA is obtained. Obtained as a correction amount QH.

In step S4, when the remaining heat quantity Q is equal to or greater than the total value of the fuel cell heating heat quantity QF, the reference start time zone use heat quantity QA, and the correction quantity QH, that is,
Q ≧ QF + QA + QH = QLT
If so, the temperature of the fuel cell is raised by the residual heat quantity Q (step S5).

On the other hand, when the residual heat quantity Q is less than the total value of the fuel cell heating heat quantity QF, the reference startup time zone use heat quantity QA, and the correction quantity QH, that is,
Q <QF + QA + QH = QLT
If so, the temperature of the fuel cell is raised by the coolant heater 100 (step S6).

  As described above, according to the present embodiment, even if the amount of heat used in the start-up time zone tA changes due to a change in season, the fuel cell start-up is automatically performed to correct and follow the temperature raising means selection threshold QLT. An extremely convenient and energy-saving cogeneration system can be provided without running out of hot water.

  In the above description, the outside air temperature-starting time zone use heat quantity characteristic was obtained through experiments, etc., but the start up time zone use heat quantity ESA was obtained in the same manner as in Embodiment 1, and this start up time zone use heat quantity ESA The outside air temperature TA detected by the air temperature sensor 106 is stored and stored in the storage unit 104, and the operation unit 105 statistically processes the accumulated start time zone use heat amount ESA and the outside air temperature TA by regression analysis or the like. Thus, it may be configured so as to obtain the outside air temperature-starting time zone use heat quantity characteristic.

[Modification 1]
Next, a first modification of the present embodiment will be described.

  In this modification, the outside air temperature sensor 106 that detects the outside air temperature is omitted in FIG. Then, the calculation unit 105 calculates the monthly average startup time zone use heat amount, and selects the temperature increase means based on the monthly average start time zone use heat amount, so that the temperature rise means in consideration of the outside temperature as a result. Select. The points other than this are the same as the configurations of FIGS. 8 and 9.

  Hereinafter, differences from the configuration of FIGS. 8 and 9 will be described in detail.

  FIG. 11 is a flowchart showing the temperature raising means selection operation of the fuel cell cogeneration system of this variation, and FIG. 12 is a graph showing the change over time in the monthly average startup time zone heat quantity in the fuel cell cogeneration system of this variation. .

  8 and 11, in the present modification, the calculation unit 105 calculates the fuel cell heating heat amount QF in step S <b> 2, and then calculates the use heat amount E in step S <b> 13 in the same manner as in the second modification of the first embodiment. Calculate.

  Thereafter, in step S15, a correction amount QH based on the outside air temperature is calculated. And when it determines with it not being at the time of starting by step S3, after that, a monthly starting time zone utilization heat amount change curve is produced by step S14 '. The other points are the same as the temperature raising means selection operation of FIG.

  Specifically, in step S14 ′, the calculation unit 105 adds the start-up time use heat amount ESA for each month out of the use heat amount E calculated in step S13, and then divides this by the number of days in the month. ESAA is calculated for each month's average startup time zone use heat amount (hereinafter referred to as monthly average startup time zone use heat amount), and is stored in the storage unit 104 together with (associated with) that month. This data is, for example, stored for the past one year from the present, and is sequentially deleted when one year elapses (new data is overwritten). Then, as illustrated in FIG. 12, the calculation unit 105 connects the plots of the monthly average startup time zone use heat amount ESAA for the past year with a straight line on the time axis-monthly average startup time zone use heat amount ESAA axis plane. (Interpolate between the plots with a straight line) Create a time-dependent change curve of monthly average start-up time use heat amount ESAA for one year (hereinafter referred to as a monthly start-up time use heat amount change curve) and store it in the storage unit 104 To do.

  On the other hand, the storage unit 104 stores a reference startup time zone use heat amount QA for setting the temperature raising means selection threshold QLT using the monthly startup time zone use heat amount change curve. The reference start time zone use heat amount QA may be set to an arbitrary value, but here, the standard start time zone use heat amount is set in the monthly start time zone use heat amount change curve.

  In step S <b> 15, the calculation unit 105 acquires the current time from the time measuring unit 103, and reads the monthly startup time zone usage heat amount change curve and the reference startup time zone usage heat amount QA from the storage unit 104. Then, the difference ΔESAA between the monthly average startup time zone use heat amount ESAA (ESAA1 in FIG. 12) corresponding to the current time t (t3 in FIG. 12) on the monthly start time zone use heat amount change curve and the reference startup time zone use heat amount QA. Is obtained as the correction amount QH.

In step S4, when the remaining heat quantity Q is equal to or greater than the total value of the fuel cell heating heat quantity QF, the reference start time zone use heat quantity QA, and the correction quantity QH, that is,
Q ≧ QF + QA + QH = QLT
If so, the temperature of the fuel cell is raised by the residual heat quantity Q (step S5).

On the other hand, when the residual heat quantity Q is less than the total value of the fuel cell heating heat quantity QF, the reference startup time zone use heat quantity QA, and the correction quantity QH, that is,
Q <QF + QA + QH = QLT
If so, the temperature of the fuel cell is raised by the coolant heater 100 (step S6).

  As described above, even in this modification, even when the amount of heat used in the start-up time changes due to a change in season, the temperature raising means selection threshold QLT is automatically corrected and followed. Therefore, an extremely convenient and energy-saving cogeneration system can be provided. In addition, the outside air temperature sensor 106 can be omitted.

  In the above description, the monthly startup time zone utilization heat amount aging curve is obtained by calculation in real time. However, in the case of simplifying the configuration, it is obtained in advance through experiments or the like and stored in the storage unit 104. It may be configured.

  In the above description, the correction amount QH is obtained based on either the outside air temperature-starting time zone use heat amount characteristic or the monthly start time zone use heat amount change curve. However, the correction amount QH may be obtained based on both of them. Good. In this case, for example, correction amounts QH ′ and QH ″ are obtained on the basis of the outside air temperature-starting time zone use heat amount characteristic and monthly start time zone use heat amount change curve, and the correction amounts QH ′ and QH ″ are set to predetermined ratios. Thus, the correction amount QH may be obtained by adding the weights at (1).

(Embodiment 3)
FIG. 13 is a block diagram showing a configuration of a fuel cell cogeneration system according to Embodiment 3 of the present invention. In FIG. 13, parts that are the same as or correspond to those in FIG.

  As shown in FIG. 13, in the present embodiment, a hot water temperature sensor 107 that detects the temperature of hot water is provided in a pipe 33 for using hot water in the hot water storage tank 16. The output of the hot water temperature sensor 107 is input to the calculation unit 105 of the control device 201. Then, calculation unit 105 selects the temperature raising means in consideration of the detected temperature of the hot water. Other points are the same as in the second embodiment.

  Next, the operation of the fuel cell cogeneration system configured as described above will be described.

  FIG. 14 is a flowchart showing the temperature raising means selection operation of the fuel cell cogeneration system of FIG.

  14, steps that are the same as or correspond to those in FIG. 9 are given the same reference numerals, and descriptions thereof are omitted.

  As shown in FIG. 14, in the present embodiment, the calculation unit 105 calculates a correction amount QH based on the outside air temperature in step S15, and then calculates a correction coefficient Kh considering hot water shortage in step S16. Specifically, a temperature detection signal is input from the hot water supply temperature sensor 107 to the calculation unit 105, and the calculation unit 105 converts the temperature detection signal to acquire the hot water supply water temperature. On the other hand, the storage unit 104 stores a predetermined threshold value of the temperature of the hot water supply in advance. This threshold is set to a normal temperature of city water, for example. The calculation unit 105 reads this threshold value from the storage unit 104 and compares it with the acquired hot water temperature, and determines that hot water has run out if the hot water temperature is equal to or lower than the threshold value. This is because when hot water runs out, the temperature of the hot water is lowered to the temperature of city water.

  Then, a correction coefficient Kh to be added to the correction amount QH calculated in step S16 is calculated. This correction coefficient Kh is a value of 1.0 or more, and is calculated so as to increase in accordance with the number of times that hot water has run out for a certain time (for example, one day).

  In step S4, the calculation unit 105 determines that the remaining heat quantity Q is equal to or greater than the total value of the fuel cell heating heat quantity QF, the reference start time zone use heat quantity QA, the product of the correction quantity QH and the correction coefficient Kh. It is determined whether it is.

When the residual heat quantity Q is equal to or greater than the total value of the fuel cell heating heat quantity QF, the reference startup time zone use heat quantity QA, and the product of the correction quantity QH and the correction coefficient Kh, that is,
Q ≧ QF + QA + QH · Kh = QLT
If so, the temperature of the fuel cell is raised by the residual heat quantity Q (step S5).

On the other hand, when the residual heat quantity Q is less than the total value of the fuel cell heating heat quantity QF, the reference startup time zone use heat quantity QA, and the product of the correction quantity QH and the correction coefficient Kh, that is,
Q <QF + QA + QH · Kh = QLT
If so, the temperature of the fuel cell is raised by the coolant heater 100 (step S6).

  As described above, in this embodiment, in the unlikely event that hot water runs out due to an increase in the amount of heat used by the user, an immediate response process is performed (the temperature raising means selection threshold QLT is automatically increased). Since the cogeneration system is controlled so as to follow the actual situation), it is possible to provide an extremely convenient and energy-saving cogeneration system without causing a shortage of heat utilization when the fuel cell 1 is started.

  It is obvious that the above configuration can be applied to the first modification of the second embodiment in the same manner as described above. In this case, the correction coefficient Kh obtained in step S16 is multiplied by the correction amount QH calculated in the first modification of the second embodiment, and in step S4, the remaining heat amount Q is changed to the fuel cell heating heat amount QF. What is necessary is just to determine whether it is more than the total value of the reference | standard starting time zone utilization heat amount QA and the product of this correction amount QH and the correction coefficient Kh.

(Embodiment 4)
The fourth embodiment of the present invention is a further modification of the first modification of the first embodiment. The hardware of the fuel cell cogeneration system of the present embodiment is configured in the same manner as the fuel cell cogeneration system of the second embodiment shown in FIG. That is, the outside air temperature sensor 106 is further added to the hardware configuration (FIG. 1) of the fuel cell cogeneration system according to the first modification of the first embodiment. Then, the calculation unit 105 of the control device 201 selects the temperature raising means in consideration of the outside air temperature and the stored hot water temperature. The other points are the same as in the first modification of the first embodiment.

  This will be specifically described below.

  FIG. 15 is a flowchart showing the temperature raising means selection operation of the cogeneration system according to Embodiment 4 of the present invention. In FIG. 15, the same steps as those in FIG.

  As shown in FIGS. 8 and 15, in the present embodiment, after the calculation unit 105 obtains the hot water temperature TW and the fuel cell operating temperature TO in step S <b> 11, the calculation unit 105 performs the outside air temperature sensor 106 in step S <b> 17. The outside air temperature is acquired by converting the temperature detection signal input from.

  In step S4, the calculation unit 105 determines whether or not the remaining heat quantity Q is equal to or greater than the fuel cell temperature rise heat quantity QF, and if the remaining heat quantity Q is less than the fuel cell temperature rise heat quantity QF, the cooling water heater 100 When the temperature of the fuel cell 1 is raised and the remaining heat quantity Q is equal to or higher than the fuel cell raised heat quantity QF, the process proceeds to step S12.

  In step S <b> 12, calculation unit 105 determines whether hot water temperature TW is equal to or higher than fuel cell operating temperature TO. Then, if the hot water temperature TW is equal to or higher than the fuel cell operating temperature TO, the temperature of the fuel cell 1 is raised by the residual heat quantity Q (step S5). move on.

  In step S18, calculation unit 105 determines whether or not hot water temperature TW is equal to or higher than outside air temperature TA. When the hot water temperature TW is lower than the outside air temperature TA, the temperature of the fuel cell 1 is raised by the cooling water heater 100. On the other hand, when the stored hot water temperature TW is equal to or higher than the outside air temperature TA, the temperature of the fuel cell 1 is raised by both the remaining heat amount Q and the cooling water heater 100 (combination). In this case, for example, the calculation unit 105 first raises the temperature of the fuel cell 1 with the remaining heat quantity Q, and the fuel with the remaining heat quantity Q is reached when the temperature of the stack detected by the stack temperature sensor 202 approaches the stored hot water temperature TW. The temperature rise of the battery 1 is stopped. Thereafter, the temperature of the fuel cell 1 is raised by the cooling water heater 100.

(Embodiment 5)
In the fifth embodiment of the present invention, the temperature raising operation of the fuel cell 1 in the first to third embodiments is changed as follows.

  That is, in step S5 of the temperature raising means selection operation of the first to third embodiments, the temperature rise of the fuel cell 1 by the residual heat quantity Q and the temperature rise of the fuel cell 1 by the cooling water heater 100 are used in combination. (The ratio of the former is greater than the ratio of the latter). Further, in step S6, the temperature rise of the fuel cell 1 by the cooling water heater 100 and the temperature rise of the fuel cell 1 by the residual heat quantity Q are used in combination, and the former is mainly subordinate (the proportion of the former is occupied by the latter). Larger than percentage). In this case, the ratio (distribution) between the temperature raising operation of the fuel cell 1 by the residual heat quantity Q and the temperature raising operation of the fuel cell 1 by the cooling water heater 100 is determined by time distribution or flow rate distribution of the cooling water.

  1, 8, and 13, when the ratio between the temperature rise of the fuel cell 1 due to the residual heat quantity Q and the temperature rise of the fuel cell 1 due to the cooling water heater 100 is determined by time distribution, the fuel cell due to the residual heat quantity Q The temperature rise of 1 and the temperature rise of the fuel cell 1 by the cooling water heater 100 are switched so that the time of both becomes a predetermined ratio.

  On the other hand, when the ratio between the temperature rise of the fuel cell 1 due to the residual heat quantity Q and the temperature rise of the fuel cell 1 due to the cooling water heater 100 is determined by the flow rate distribution of the cooling water, the flow rate adjustment valve 13 and the flow rate adjustment valve 14. Are opened at the same time, and the degree of opening of both valves is adjusted so that the ratio of the flow rate of the cooling water passing through the two is the determined ratio. When the cooling water pump 9 and the cooling water heater 10 are operated, the hot water storage pump 20 is operated, and the circulation direction switching means 17 is controlled so that the hot water is circulated in the B direction.

  Even with such a configuration, substantially the same effect as in the first to third embodiments can be obtained. However, when the cooling water heater 100 is used together when the fuel cell 1 is to be started up only by the residual heat quantity Q in the first to third embodiments, the energy efficiency of the fuel cell cogeneration system is reduced accordingly. On the other hand, in the first to third embodiments, when the remaining heat quantity Q is used in combination when the fuel cell 1 should be started only by the cooling water heater 100, the amount of heat that can be used by the user in the startup time period tA ( Here, the amount of hot water is reduced.

  In the first to fifth embodiments, the remaining heat amount detecting means 101 is constituted by a plurality of temperature sensors attached to the surface of the hot water storage tank 16 at intervals in the vertical direction. , 13, a heat exchanger outlet temperature sensor 18 and a heat exchanger inlet temperature sensor 19 respectively disposed at the outlet and inlet of the heat exchanger 12 (when hot water is passed in the direction of arrow A). And a flow meter (not shown) disposed in the exhaust heat recovery pipes 15a and 15b. In the calculation unit 105, the temperature difference between the heat exchanger outlet temperature sensor 18 and the heat exchanger inlet temperature sensor 19 is determined by the flow meter. The exhaust heat recovery heat amount may be calculated from the product of the detected flow rate of the hot water stored in the exhaust heat recovery pipes 15a and 15b, and the remaining heat amount obtained by subtracting the use heat amount E from the exhaust heat recovery heat amount may be calculated.

  In the first to fifth embodiments, the case where the recovered waste heat is used for hot water supply is shown, but the present invention is similarly applied to the case where the recovered waste heat is used for heating or drying. Similar effects can be obtained.

  Moreover, in Embodiments 1-5, although the hot water storage tank 16 was comprised with the thing of the laminated boiling type, you may comprise this with types other than a laminated boiling type.

  In the first to fifth embodiments, the antifreeze liquid is used as the internal heat transport medium and water is used as the external heat transport medium. However, other heat transport media may be used.

  In the first to fifth embodiments, the operation of the entire fuel cell cogeneration system and the temperature raising means selection operation are controlled by one control device 201. However, a plurality of required configurations of the fuel cell cogeneration system are used. A plurality of control devices may be arranged corresponding to the elements, and the plurality of control devices may cooperate to control the operation of each component and the entire fuel cell cogeneration system. Therefore, in this specification, the control device means both a single control device and a control device group including a plurality of control devices working together.

  In the first to fifth embodiments, the control device 201 uses the storage unit 104 including an internal memory as a storage unit. However, the information recording medium and the information recording medium can be mounted and information can be written to and read from the information recording medium. An information recording medium driving device may be used as the storage means.

  The fuel cell cogeneration system of the present invention is useful as a fuel cell cogeneration system that can improve the convenience by preventing running out of hot water.

It is a block diagram which shows the structure of the fuel cell cogeneration system which concerns on Embodiment 1 of this invention. It is a flowchart which shows the temperature rising means selection operation | movement of the fuel cell cogeneration system of FIG. 6 is a flowchart showing a temperature raising means selection operation of the fuel cell cogeneration system according to the first modification of the first embodiment. 6 is a flowchart showing a temperature raising means selection operation of a fuel cell cogeneration system according to a second modification of the first embodiment. It is a graph which shows a time-dependent change of the amount of residual heat of the day. It is a graph which shows the time-dependent change of the heat usage amount by the user of 1 day. 10 is a flowchart showing a temperature raising means selection operation of a fuel cell cogeneration system according to a third modification of the first embodiment. It is a block diagram which shows the structure of the fuel cell cogeneration system which concerns on Embodiment 2 of this invention. It is a flowchart which shows the temperature rising means selection operation | movement of the fuel cell cogeneration system of FIG. It is a graph which shows the change of the amount of use heat of starting time zone to change of outside temperature. 6 is a flowchart showing a temperature raising means selection operation of a fuel cell cogeneration system according to a first modification of the second embodiment. It is a graph which shows a time-dependent change of the monthly average starting time zone utilization heat amount. It is a block diagram which shows the structure of the fuel cell cogeneration system which concerns on Embodiment 3 of this invention. It is a flowchart which shows the temperature rising means selection operation | movement of the fuel cell cogeneration system of FIG. It is a flowchart which shows the temperature rising means selection operation | movement of the fuel cell cogeneration system which concerns on Embodiment 4 of this invention. It is a block diagram which shows the structure of the conventional fuel cell cogeneration system.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fuel cell 2 Fuel processing apparatus 3 Reformer 4 Transformer 5 Fuel side humidifier 6 Air supply apparatus 7 Oxidizing gas side humidifier 8 Cooling water piping 9 Cooling water pump 12 Heat exchanger 13 Flow rate adjustment valve 14 Flow rate adjustment valve 15a , 15b Piping 16 Heat utilization part (hot water storage tank)
17 Circulation direction switching means (exhaust heat transport control means)
DESCRIPTION OF SYMBOLS 18 1st heat exchange temperature sensor 19 2nd heat exchange temperature sensor 20 Hot water storage pump 21 1st flow-path switching valve 22 2nd flow-path switching valve 23 Discharge side branch joint 24 Suction side branch joint 31, 32, 33 Piping 100 Cooling water heater 101A to 101C First to third tank temperature sensors 102 Flow meter (utilization heat quantity detection means)
DESCRIPTION OF SYMBOLS 103 Time measuring part 104 Memory | storage part 105 Calculation part 106 Outside temperature sensor 107 Hot-water supply temperature sensor 201 Control apparatus 202 Stack temperature sensor

Claims (16)

A fuel cell; a cooling system that circulates the internal heat transport medium so as to exchange heat between the fuel cell and the internal heat transport medium; an internal heat transport medium heater that heats the internal heat transport medium; and an external heat transport medium. Exhaust heat utilization for circulating heat through the heat utilization section so that heat exchange between the heat utilization section that can be used by the user and the internal heat transport medium and the external heat transport medium of the cooling system exchanges heat. A system, a residual heat amount detecting means for detecting a residual heat amount of the heat utilization unit, and a control device,
When the fuel cell is started up, the control device has a detected residual heat amount of the heat utilization unit that is equal to or higher than a fuel cell heating amount that is a heat amount required to raise the temperature of the fuel cell to an operating temperature. It is determined whether the amount of heat is greater than a certain threshold heat amount, and based on the determination result, the remaining heat amount of the heat utilization part is transferred to the internal heat transport medium by heat exchange to raise the temperature of the fuel cell. The first temperature raising operation and / or the second temperature raising operation is determined by allocating a temperature operation and a second temperature raising operation for heating the internal heat transport medium by the internal heat transport medium heater to raise the temperature of the fuel cell. A fuel cell cogeneration system that raises the temperature of the fuel cell to the operating temperature by a temperature raising operation of 2.   When the residual heat quantity is equal to or greater than the threshold heat quantity, the control device mainly raises the temperature of the fuel cell to the operating temperature in the first temperature raising operation, and the residual heat quantity is less than the threshold heat quantity. 2. The fuel cell cogeneration system according to claim 1, wherein the temperature of the fuel cell is raised to the operating temperature mainly in the second temperature raising operation. Means for detecting the temperature of the external heat transport medium stored in the heat utilization section;
When the residual heat quantity is less than the threshold heat quantity, the control device mainly raises the temperature of the fuel cell to the operation temperature in the second temperature raising operation, and the residual heat quantity is equal to or greater than the threshold heat quantity. In this case, it is determined whether or not the detected temperature of the external heat transport medium is equal to or higher than the operating temperature, and based on the determination result, the first temperature raising operation and the second temperature raising operation are performed. 2. The fuel cell cogeneration system according to claim 1, wherein the fuel cell is heated to the operating temperature by the first temperature raising operation and the second temperature raising operation.   When the temperature of the external heat transport medium is equal to or higher than the operating temperature, the control device mainly raises the temperature of the fuel cell to the operating temperature in the first temperature raising operation, 4. The fuel cell cogeneration system according to claim 3, wherein when the temperature is lower than the operation temperature, the fuel cell is heated to the operation temperature mainly in the second temperature raising operation. 5. Means for detecting the temperature outside the fuel cell;
When the temperature of the external heat transport medium is equal to or higher than the operating temperature, the control device mainly raises the temperature of the fuel cell to the operating temperature in the first temperature raising operation, When the temperature is lower than the operating temperature, it is determined whether the temperature of the external heat transport medium is equal to or higher than the detected external temperature, and the first temperature raising operation is performed based on the determination result. 2. The fuel according to claim 1, wherein the fuel cell is heated to the operating temperature by determining the distribution between the first temperature raising operation and the second temperature raising operation. Battery cogeneration system.   When the temperature of the external heat transport medium is equal to or higher than the detected external temperature, the control device combines the first temperature raising operation and the second temperature raising operation to combine the fuel cell. The temperature is raised to the operating temperature, and when the temperature of the external heat transport medium is lower than the detected outside air temperature, the fuel cell is mainly raised to the operating temperature in the second temperature raising operation. The fuel cell cogeneration system according to claim 5.   When the threshold heat quantity is composed of the fuel cell temperature rise heat quantity and a predetermined heat quantity, and when the remaining heat quantity is equal to or greater than the threshold heat quantity, the control device mainly performs the first temperature rise operation. 2. The fuel according to claim 1, wherein when the residual heat quantity is less than the threshold heat quantity, the fuel cell is mainly heated up to the operation temperature in the second temperature raising operation. Battery cogeneration system.   The fuel according to claim 7, wherein the predetermined amount of heat is an amount of heat used in a start-up time period that is assumed to be used by a user in a start-up time period extending from a start time of the fuel cell to a predetermined time. Battery cogeneration system. Means for detecting the amount of heat used due to the use of an external heat transport medium stored in the heat utilization unit; means for acquiring time;
Storage means for storing the detected amount of heat used together with the acquired time,
9. The fuel cell cogeneration system according to claim 8, wherein the control device calculates the start-up time zone use heat amount based on the use heat amount stored together with the time.   10. The fuel cell cogeneration system according to claim 9, wherein the control device calculates the start-up time zone use heat amount so as to take an average value over a predetermined period. The predetermined amount of heat consists of a fixed amount and a correction amount,
The fuel cell cogeneration system according to claim 9, wherein the control device changes the correction amount based on the calculated start-up time zone use heat amount. Means for detecting the temperature outside the fuel cell;
The fuel cell cogeneration system according to claim 7, wherein the control device changes the predetermined amount of heat based on the detected external temperature. Means for detecting the temperature of the utilized external heat transport medium,
8. The fuel cell cogeneration system according to claim 7, wherein the control device changes the predetermined amount of heat in accordance with a frequency at which the detected temperature of the used external heat transport medium becomes equal to or lower than a predetermined value.   The fuel cell cogeneration system according to claim 1, wherein the external heat transport medium is water, and the heat utilization unit is a hot water storage tank.   The fuel cell cogeneration system according to claim 14, wherein the hot water storage tank is of a stacked boiling type.   When the residual heat amount is equal to or greater than the threshold amount, the control device raises the temperature of the fuel cell to the operating temperature only by the first temperature raising operation, and the residual heat amount is less than the threshold heat amount. In this case, the fuel cell cogeneration system according to claim 2, wherein the temperature of the fuel cell is raised to the operating temperature only by the second temperature raising operation.

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