JP2005085663A5 - - Google Patents

Description

Fuel cell system

The present invention relates to a fuel cell system that generates electricity using a fuel cell.

Is a conventional fuel cell systems, there is a fuel cell power generation system utilizing both power and heat efficiently to maximize (e.g., see Patent Document 1). Figure 12 shows a conventional fuel cell system described in Patent Document 1.

  In FIG. 12, a hydrogen generator 1 for generating a gas rich in hydrogen from a raw material fuel such as natural gas or methanol and a raw water necessary for a steam reforming reaction, and a blower fan for supplying air as an oxidant gas An air humidifier 3 for humidifying the supply air, a fuel cell 4 for generating electricity by reacting the product gas obtained in the hydrogen generator 1 and the oxidant gas from the air blower 2; From the DC / AC converter 5 that converts the DC power generated by the fuel cell 4 into AC 200V, the generated gas obtained by the hydrogen generator 1, the oxidant gas from the blower 2, and the fuel cell 4, respectively. A hot water storage tank 6 for storing hot water obtained by recovering the exhaust heat of the water, a controller 7 for controlling a series of operations from start-up to power generation, and load power detection for detecting load power at a household power load Consists of means 8

Here, the controller 7 controls the power generation output from the DC / AC converter 5 according to the power load in the home by the load power detection means 8, and the generated gas, the oxidant gas, and the exhaust heat from the fuel cell 4. And efficiently controlling both electric power and heat. In addition, hot water in the hot water storage tank 6 is automatically supplied to a bathtub or the like during a power heavy load time period.
JP 2002-352834 A

  However, in the conventional configuration, when the power load is small, the power generation is stopped, or when the power load is frequently turned on and off, the power is wasted even if it is generated or stopped. When it was inside, it was inefficient and had the problem of requiring startup energy to restart.

The present invention is intended to solve the conventional problems, the power generation of the fuel cell system to continue the power generation even when the power load is small, the fuel cell system which is adapted surplus power can be used as hot water instead of the hot The purpose is to provide.

In order to solve the above conventional problems, the fuel cell system of the present invention has a heater in the hot water storage tank, varying the power to the heat, it is to stored in the hot water storage tank as hot water.

  With this configuration, even when the power load is reduced, the surplus power can be converted into heat and stored as hot water in the hot water storage tank, so that power generation can be continued and the system can be started and stopped frequently. It is possible to prevent waste of energy.

According to the fuel cell system of the present invention the storage, even if the power load is equal to or less than a minimum generated power, by supplying a surplus power to the heater in the hot water storage tank, a hot water storage tank as hot water by changing the power to the heat This configuration eliminates the need to continuously generate power and waste energy. Furthermore, since the system is not frequently started and stopped, energy loss at startup can be eliminated.

A first invention includes a hydrogen generator, a fuel cell that generates power by reacting a product gas obtained by the hydrogen generator and an oxidant gas, and a controller that controls a series of operations from the start of operation to power generation A DC / AC converter for converting DC power generated by the fuel cell into AC power, load power detection means for detecting load power at the power load, and a product gas or oxidant obtained by the hydrogen generator A hot water storage tank for storing hot water obtained by utilizing exhaust heat from the gas and the fuel cell, and a heater connected to the hot water storage tank , when the load power of the day fluctuates, When the generated power is output so that it does not fall below the minimum generated power of the fuel cell system, and the load power falls below the minimum generated power by the load power detection means, the controller supplies the heater with the power from the DC / AC converter. Converting to heat Even if the power load is below the minimum generated power by continuing the power generation, the surplus power is supplied to the heater in the hot water storage tank, so that the power is converted into heat and stored in the hot water storage tank as hot water Thus, it is not necessary to continue power generation and waste energy. Furthermore, since the system is not frequently started and stopped, it is possible to eliminate the energy loss at the time of startup.

  In particular, in addition to the first invention, the second invention is provided with an air temperature detecting means, and when the difference between the home air temperature and the outside air temperature is equal to or greater than a certain value, the controller heaters the electric power from the DC / AC converter. By increasing the ratio of supply to heat and converting it into heat, the shortage of hot water can be solved, and power generation can be continued even if the power load is reduced, and energy loss can be eliminated.

  In addition to the first invention, the third invention has a configuration in which the ratio of supplying generated power to the heater is increased in the low temperature period (for example, from November to March) by the time measuring means for measuring the date. In addition to eliminating the shortage of hot water, power generation can be continued even if the power load is reduced, and energy loss can be eliminated.

  In addition to the first invention, the fourth aspect of the invention provides the generated power when the amount of hot water used exceeds a certain level by the hot water usage amount detecting means for detecting the amount of hot water used in the hot water storage tank. With the configuration in which the ratio supplied to the heater is increased, the shortage of hot water can be solved, and power generation can be continued even if the power load is reduced, and energy loss can be eliminated.

  In the fifth aspect of the invention, in addition to the first aspect of the invention, when the reverse power flow is detected by the reverse power flow detecting means for detecting the reverse power flow to the system power supply, the power for the reverse power flow is supplied to the heater. Thus, reverse power flow can be prevented.

  In addition to any one of the first to fifth inventions, the sixth invention is provided with a hot water temperature detection thermistor at the bottom of the hot water storage tank, and the hot water temperature detection thermistor allows the hot water temperature in the hot water storage tank to reach the lowest temperature. When the temperature reaches a certain level or more, the hot water temperature in the hot water storage tank can be adjusted by a configuration in which the hot water supply temperature is raised from the set temperature.

  In addition to the sixth invention, the seventh invention is provided with a cooling fan in the hot water storage tank, and when the hot water temperature in the hot water storage tank reaches a certain level or more up to the lowermost part, the hot water in the hot water storage tank is The temperature of the hot water in the hot water storage tank can be adjusted by the configuration of cooling the water.

  In particular, in addition to the sixth or seventh invention, the eighth invention is configured to notify the user in advance of the use of hot water when the hot water temperature in the hot water storage tank reaches the upper limit up to the lowest level. The power generation of the fuel cell system can be continued.

  Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1)
Figure 1 is a block diagram of a fuel cell system in the first embodiment of the present invention. In FIG. 1, the same components as those in FIG.

  In FIG. 1, the heater 9 is installed in the hot water storage tank 6 to convert surplus power into heat and store hot water in the hot water storage tank 6. When the load power becomes lower than the minimum generated power by the load power detection means 8, the controller 7 is configured to continue power generation by supplying power from the DC / AC converter 5 to the heater 9 and converting it to heat. .

Here, the operation of the fuel cell system of FIG. 2 will be described using a flowchart. In step 1, the fuel cell system is activated, and hydrogen-rich gas is generated in the hydrogen generator 1. If the temperature of each part reaches the set temperature, power generation is started in step 2. In step 3, the load power detection means 8 performs a power load following operation according to the power load in the home. If it is detected in step 4 that the power load is equal to or lower than the minimum generated power (here, 400 W or lower), the minimum generated power 400 W is maintained and output in step 5. In step 6, a value obtained by subtracting the load power from the generated power by calculation is set as surplus power. In step 7, the surplus power is supplied to the heater 9, and the power is converted into heat and consumed.

Further, as shown in the daily operation diagram in FIG. 3 , when the load power of the day fluctuates, the generated power is output so that the load power does not fall below the minimum generated power of the fuel cell system. and, although usually outputs the generated power to follow the load power, load power minimum power is also equal to or smaller than (where 400W is), generated power and outputs to maintain 400W.

  According to such a configuration, even when the power load becomes equal to or lower than the minimum generated power, by supplying surplus power to the heater 9 in the hot water storage tank 6, the power is converted into heat and stored in the hot water storage tank 6 as hot water. This eliminates the need to continue power generation and waste energy. Furthermore, since the system is not frequently started and stopped, it is possible to eliminate the energy loss at the time of startup.

  In this embodiment, the heater 9 is provided to convert electric power into heat, but an IH (induction heater) or a simple electric heater may be used.

(Embodiment 2)
Figure 4 is a block diagram of a fuel cell system in the second embodiment of the present invention. 4, the same components as those in FIGS. 1 and 12 are denoted by the same reference numerals, and the description thereof is omitted.

  In FIG. 4, the air temperature detecting means 10 detects the home air temperature and the outside air temperature. The controller 7 is configured to change the ratio of supplying the generated power to the heater 9 based on the temperature difference between the home air temperature and the outside air temperature detected by the air temperature detecting means 10. Here, when the difference between the home air temperature and the outside air temperature is 5 ° C. or more, the power supply ratio to the heater 9 is changed. For example, in (Table 1), when the value obtained by subtracting the outside temperature from the home temperature is 5 ° C. or more and less than 10 ° C., the energization ratio to the heater 9 is increased by 10% from that point, and 10 ° C. or more and less than 15 ° C. The difference is 20% up, the difference between 15 ° C. and less than 20 ° C. is 35% up, and the difference between 20 ° C. and more is 50% up. Here, the difference between the home air temperature and the outside air temperature is used as a reference, but it is because the judgment is based on the relative temperature rather than each temperature itself.

  According to such a configuration, when the difference between the home air temperature and the outside air temperature is greater than or equal to a certain level by the air temperature detection means 10, the ratio of supplying the generated power to the heater 9 is increased, so by increasing the amount of hot water rather than the power In addition to eliminating the shortage of hot water, power generation can be continued even if the power load is reduced, and energy loss can be eliminated.

  In the present embodiment, the supply ratio of electric power to the heater 9 is changed based on the value obtained by subtracting the outside temperature from the inside temperature. However, the ratio may be changed according to the outside temperature itself or the inside temperature itself. good. Further, the setting of the temperature difference interval and the value of the ratio increase rate may be freely changed.

(Embodiment 3)
Figure 5 is a block diagram of a fuel cell system in a third embodiment of the present invention. In FIG. 5, the same components as those in FIGS. 1, 4, and 12 are denoted by the same reference numerals, and description thereof is omitted.

  In FIG. 6, the time measuring means 11 has a clock function capable of measuring the date. The controller 7 detects the low temperature period from November to March by the time measuring means 11 and changes the ratio of supplying the generated power to the heater 9 at this time. For example, in (Table 2), in November, the energization ratio of the generated power to the heater 9 is increased by 5%. Similarly, December is up 10%. The amount of hot water is secured by increasing 20% in January, increasing 30% in February, and increasing 10% in March.

  According to such a configuration, since the ratio of supplying generated power to the heater 9 is increased by the time measuring means 11 during the low temperature period (for example, from November to March), the shortage of hot water is solved and the power load is reduced. However, power generation can be continued and energy loss can be eliminated.

  In the present embodiment, the low temperature period is from November to March. However, the timing may be shifted depending on the installation location, and naturally the ratio supplied to the heater 9 may be changed.

(Embodiment 4)
6 is a block diagram of a fuel cell system according to a fourth embodiment of the present invention. In FIG. 6, the same components as those in FIGS. 1, 4, 5, and 12 are denoted by the same reference numerals, and description thereof is omitted.

  In FIG. 6, the hot water usage detection means 12 detects the usage of hot water in the hot water storage tank 6. The controller 7 is configured to change the ratio of supplying the generated power to the heater 9 when the amount of hot water used exceeds a certain value (here, 5 L (liters) or more) by the hot water usage detection means 12. For example, in Table 3, if the amount of hot water used is 5 L or more and less than 10 L per minute, the energization ratio to the heater 9 is increased by 5% at that time. Similarly, the amount of hot water is secured by increasing 10% at a rate of 10L or more and less than 15L / min, increasing 30% at a rate of 15L or more and less than 20L / min, and increasing by 50% at 20L or more per minute.

  According to such a configuration, when the amount of hot water used reaches a certain level or more by the hot water usage detection means 12, the ratio of supplying the generated power to the heater is increased. Even if the power drops, power generation can be continued and energy loss can be eliminated.

  In the present embodiment, the minimum usage amount is 5 L per minute, but the set amount may be changed according to the usage situation at home.

(Embodiment 5)
Figure 7 is a block diagram of a fuel cell system according to a fifth embodiment of the present invention. 7, the same components as those in FIGS. 1, 4, 5, 6, and 12 are denoted by the same reference numerals, and description thereof is omitted.

  In FIG. 7, the reverse power flow detecting means 13 detects that the generated power exceeds the load power in the home and the power is sent back to the system power source. The controller 7 is configured to prevent the reverse power flow by supplying the power corresponding to the reverse power flow to the heater 9 when the reverse power flow detecting means 13 detects that the power is flowing backward.

  Here, it demonstrates using the flowchart of FIG. In step 11, the fuel cell system is activated, and hydrogen-rich gas is generated in the hydrogen generator 1. When the temperature of each part reaches the set temperature, power generation is started in step 12. In step 13, the load power detection means 8 performs the power load following operation according to the power load in the home. If it is detected in step 14 that the household power load is smaller than the generated power, a value obtained by subtracting the load power from the generated power by calculation in step 15 is set as surplus power. In step 16, the surplus power is supplied to the heater 9, and the power is converted into heat and consumed.

  In addition, as shown in the daily operation chart in FIG. 9, theoretically, the generated power is output following the power load in the home, but the load power always fluctuates finely, and the load power value Strictly speaking, the triangular area in the figure is causing a reverse power flow, although it generates a slightly smaller power value. For this reason, electric power is supplied to the heater 9 each time, and the electric power is converted into heat and consumed, thereby preventing reverse power flow.

  According to such a configuration, when the reverse power flow is detected by the reverse power flow detection means 13, the power for the reverse power flow is supplied to the heater 9, so that the reverse power flow can be prevented.

(Embodiment 6)
Figure 10 is a block diagram of a fuel cell system in a sixth embodiment of the present invention. 10, the same components as those in FIGS. 1, 4, 5, 6, 7, and 12 are denoted by the same reference numerals, and description thereof is omitted.

  In FIG. 10, the hot water temperature detection thermistor 14 is installed at the lowermost part of the hot water storage tank 6 and detects the hot water temperature at the lowermost part of the hot water storage tank 6. When the temperature at the bottom of the hot water storage tank 6 reaches the upper limit of the hot water temperature in the hot water storage tank 6, for example, 80 ° C., the controller 7 reaches 80 ° C. in the hot water storage tank. It means that it is necessary to lower the temperature using hot water. Here, it is set as the structure which raises preset temperature at the time of using hot water to 1 degreeC at a maximum to 5 degreeC. At first, raise the set temperature by 1 ° C, but if it is necessary to lower the hot water temperature further, raise the set temperature to a maximum of 5 ° C to avoid the risk of burns as much as possible. is there.

  According to this configuration, when the hot water temperature in the hot water storage tank 6 reaches a certain level or more by the hot water temperature detection thermistor 14, the hot water supply temperature is raised from the set temperature and supplied. The temperature of the hot water can be adjusted.

(Embodiment 7)
Figure 11 is a block diagram of a fuel cell system according to a seventh embodiment of the present invention. 11, the same components as those in FIGS. 1, 4, 5, 6, 7, 10, and 12 are denoted by the same reference numerals, and the description thereof is omitted.

  In FIG. 11, the cooling fan 15 is installed in the hot water storage tank 6 and serves to cool the hot water in the hot water storage tank 6 and lower the hot water temperature. When the temperature of the lowest part of the hot water storage tank 6 reaches the upper limit of the hot water temperature in the hot water storage tank 6, for example, 80 ° C., the controller 7 has reached 80 ° C. in the hot water storage tank. This means that it is necessary to lower the hot water temperature. Here, the cooling fan 15 forcibly sends cool air to lower the hot water temperature.

  According to such a configuration, when the hot water temperature in the hot water storage tank 6 reaches a certain level or more up to the lowest part, the hot water in the hot water storage tank is cooled by the cooling fan, so that the hot water temperature in the hot water storage tank 6 can be adjusted. It is.

  Moreover, when the hot water temperature in the hot water storage tank 6 reaches an upper limit to the lowest part, it is set as the structure which alert | reports abnormality.

  According to such a configuration, when the hot water temperature in the hot water storage tank 6 reaches the uppermost limit, an abnormality is notified, so that the user can be encouraged to use hot water in advance and power generation of the fuel cell system can be continued.

  The control device for a fuel cell system according to the present invention supplies a surplus power to a heater provided in the hot water storage tank even when the power load is lower than the minimum generated power, thereby converting the electric power into heat and the hot water storage tank as hot water. Since the power generation is continued by the configuration of storing in the battery, it is possible to eliminate the energy loss at the time of starting the system, which is useful for performing power generation using the fuel cell. It can also be applied to cogeneration systems using other batteries and power sources.

Block diagram of a fuel cell system according to the first embodiment of the present invention Flow chart showing the operation of the fuel cell system according to the first embodiment of the present invention Running operation diagram of one day of a fuel cell system according to the first embodiment of the present invention Block diagram of a fuel cell system in the second embodiment of the present invention Block diagram of a fuel cell system in a third embodiment of the present invention Block diagram of a fuel cell system according to a fourth embodiment of the present invention Block diagram of a fuel cell system according to Embodiment 5 of the present invention Flow chart showing the operation of the fuel cell system according to Embodiment 5 of the present invention Running operation diagram of one day of a fuel cell system according to Embodiment 5 of the present invention Block diagram of a fuel cell system in a sixth embodiment of the present invention Block diagram of a fuel cell system according to a seventh embodiment of the present invention Configuration diagram of a conventional fuel cell system

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Hydrogen generator 4 Fuel cell 5 DC / AC converter 6 Hot water storage tank 7 Controller 8 Load electric power detection means 9 Heater 10 Air temperature detection means 11 Timekeeping means 12 Hot water usage detection means 13 Reverse power flow detection means 14 Hot water temperature detection thermistor 15 Cooling fan

Claims (8)

A hydrogen generator, a fuel cell that generates power by reacting a product gas obtained by the hydrogen generator and an oxidant gas, a controller that controls a series of operations from start of operation to power generation, and the fuel cell A DC / AC converter for converting the DC power generated at the AC power into AC power, load power detection means for detecting load power at the power load, the generated gas or oxidant gas obtained by the hydrogen generator, and the a hot water storage tank for storing hot water obtained by using the exhaust heat from the fuel cell, and a heater connected to the hot water storage tank, when the load power of the day is fluctuating load power fuel When the generated power is output so that it does not fall below the minimum generated power of the battery system, and the load power becomes lower than the minimum generated power by the load power detection means, the controller converts the power from the DC / AC converter to the heater. To serve Fuel cell system, characterized by continuing the power generation by converting into heat by. A temperature detecting means is provided, and the controller increases the ratio of supplying electric power from the DC / AC converter to the heater and converting it to heat when the difference between the domestic temperature and the outside temperature is a certain level or more. The fuel cell system according to claim 1 . It is provided with a time measuring means for measuring the date, and in the low temperature period from autumn to winter, the controller increases the ratio of supplying electric power from the DC / AC converter to the heater and converting it into heat. Item 4. The fuel cell system according to Item 1 . Hot water usage detection means that detects the usage status of hot water in the hot water storage tank is provided, and if the hot water usage exceeds a certain level, the controller supplies power from the DC / AC converter to the heater and converts it into heat. The fuel cell system according to claim 1, wherein the ratio of increasing is increased . A reverse power flow detecting means for detecting a reverse power flow to the system power supply is provided, and when the reverse power flow is detected, the controller supplies the power for the reverse power flow to the heater to prevent the reverse power flow. 1. The fuel cell system according to 1 . A hot water temperature detection thermistor is provided at the lowermost part of the hot water storage tank, and when the temperature to the lowermost part in the hot water storage tank reaches a certain level or more, the controller raises the hot water supply temperature above the set temperature and supplies it. The fuel cell system according to any one of claims 1 to 5 . The hot water storage tank is provided with a cooling fan, and the controller cools the hot water in the hot water storage tank by the cooling fan when the temperature up to the lowest part in the hot water storage tank reaches a certain level or more. The fuel cell system described . The fuel cell system according to claim 6 or 7, wherein when the temperature up to the lowermost part in the hot water storage tank reaches a limit, the controller notifies an abnormality .