JP2006073265A - Fuel cell power generation system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell power generation system capable of determining generating output with which the power generation device of the fuel cell can operate and starting and stopping of it, according to heat demand of real time of a consumer. <P>SOLUTION: The fuel cell power generation system is equipped with a hot water tank 3 which stores the hot water from a fuel cell 1 and can discharge the hot water to the outside, at least a first and a second thermometers 6 which measure the temperatures of the hot water in the tank 3 and, by dividing the inside of the tank 3 at least into two pieces virtually in vertical direction, measure the temperatures of the hot water respectively corresponding to each virtual divided space, and a control device 8 which inputs the measured value of each thermometer 6 and changes the upper limit of the power generating output of the fuel cell 1, when the measured value of the thermometers is a first established value or lower than the temperature of the hot water supply side supplied from the fuel cell 1 to the tank 3, and the measured value of the second thermometer is lower than the first established value and is a second established value or lower closely resembling a cooling temperature which the fuel cell can permits. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a fuel cell power generation system that includes a hot water storage tank that stores heat generated by, for example, a household fuel cell power generation device, and that can adjust the output of the fuel cell power generation device according to the amount of heat stored in the hot water storage tank.

  Conventionally, a fuel cell power generation system is known as a system that directly converts chemical energy of fuel into electricity. This fuel cell power generation system is a system in which hydrogen as a fuel and oxygen as an oxidant are reacted electrochemically to directly extract electricity, and electric energy can be extracted with high efficiency. Furthermore, this fuel cell power generation system has extremely excellent environmental characteristics such as low emission of air pollutants and low noise.

  Recently, it is expected that fuel cell power generation equipment having a hot water supply device as a household cogeneration system will be widespread, and installed in actual homes at various places and are being tested. Because the scale is different from cogeneration systems installed in factories, etc., in particular, how to match the electricity and heat obtained from the fuel cell power generator with the household power demand and heat demand will promote the introduction to the home To be important.

  However, household electricity demand and heat demand vary from household to household, and vary depending on changes in environmental conditions such as seasons and temperatures, so a uniform operating pattern cannot be determined and it is difficult to predict accurately. .

For this reason, many new measuring instruments and control devices are installed, and electricity demand and heat demand of consumers are collected every day, and demand forecasts are made using these, and many methods of operating based on these forecasts are proposed. (See Patent Documents 1 to 6). In addition, since all the proposals are based on engine cogeneration, the operation method is based only on the ON / OFF operation of starting or stopping the cogeneration equipment. There were no proposals on how to drive the vehicle.
JP2002-138902 JP 2002-213303 A JP 2001-248910 A JP 2001-248909 A JP 2001-248907 A JP 2003-87970 A

  As described above, the proposals so far have been focused on accurately predicting the daily power / heat demand of consumers. In other words, the main focus is on how to accurately predict an operation pattern that uses up hot water just at the end of the day, assuming that the same efficiency is always achieved by ON / OFF operation of starting or stopping. It has been.

Specifically, each of the patent documents described above has the following problems.
(a) Predictive operation that uses up hot water just at the end of the day, so when the demand for electricity is high and the demand for hot water supply is low, such as in summer, it becomes an operation pattern that hardly operates, making no sense as a cogeneration system.

 Certainly, in order to improve the energy-saving performance of cogeneration equipment, it is necessary to minimize the generation of heat that exceeds demand. However, in the setting to use up hot water just at the end of the day, In particular, since there is little demand for hot water supply, there is no need to operate the cogeneration. However, on the other hand, the demand for electric power increases because the frequency of use of air conditioners and the like increases. There is no contribution to this.

(B) It cannot respond to unexpected changes in demand, and also affects the predicted operation thereafter, reducing economic efficiency and energy saving.

  In the operation with the operation pattern obtained from the demand forecast based on the past power demand and heat demand or the operation with the schedule of the daily operation pattern, when the electricity / heat demand decreases due to sudden outing, etc. When the demand for electricity and heat increases due to visitors, etc., operation that meets the demand is not possible. In addition, if the change is unexpected for a short time, the subsequent demand prediction is not particularly affected, but if the change is made on a daily basis, the subsequent demand prediction is also affected. In other words, it cannot respond to unexpected changes in demand, and also affects the predicted operation thereafter, reducing economic efficiency and energy saving.

(C) Driving is carried out even when absent.

  As long as the operation is performed with the operation pattern obtained from the demand prediction based on the past power demand and heat demand, as described above, the home cogeneration remains operated even when suddenly going out. Since it is a power generation device that uses city gas or LP gas as fuel, it is desirable to stop it for security reasons. There is no response to this.

(D) There is no proposal that defines the output at the partial load of the fuel cell.

  In the schedule operation such as the operation in the cogeneration system installed in Patent Document 6 or the factory, the stop timing of the cogeneration device is clearly defined, but here again, whether to start or stop Only ON / OFF operation is considered.

  The present invention has been proposed in view of the situation as described above, and its main purpose is to determine the power generation output that can be operated by the fuel cell power generation device and to start and stop it according to the real-time heat demand of the consumer. It is providing the fuel cell power generation system which can perform.

In order to achieve the above object, the invention corresponding to claim 1 is a fuel cell capable of generating electric power and outputting hot water warmed by exhaust heat generated by the generation of the electric power;
A hot water storage tank for storing hot water from the fuel cell and discharging the hot water to the outside;
At least first and second thermometers for measuring the temperature of hot water in the hot water tank;
Means for setting the power generation output of the fuel cell in accordance with the amount of heat stored in the hot water tank obtained based on the temperature measurement value measured by each thermometer;
Is a fuel cell power generation system.

In order to achieve the above object, an invention corresponding to claim 2 is a fuel cell capable of generating electric power and outputting hot water warmed by exhaust heat generated by the generation of the electric power;
A hot water storage tank for storing hot water from the fuel cell and discharging the hot water to the outside;
The temperature of the hot water in the hot water tank is measured, the hot water tank is virtually divided into at least two in the vertical direction, and the temperature of the hot water is measured corresponding to each virtual divided space. At least first and second thermometers;
The first and second thermometer measurement values are input, and the first thermometer measurement value is lower than the temperature of the hot water supply side supplied from the fuel cell into the hot water tank. And when the measured value of the second thermometer is lower than the first set value and lower than or equal to a second set value that approximates a cooling temperature that the fuel cell can tolerate, Power generation output changing means for changing the upper limit value;
Is a fuel cell power generation system.

  ADVANTAGE OF THE INVENTION According to this invention, the fuel cell power generation system which can perform the determination of the power generation output which can drive | operate a fuel cell power generation apparatus, and starting / stopping according to the real-time heat demand of a consumer can be provided.

  Embodiments of a fuel cell power generation system according to the present invention will be described below with reference to the drawings. FIG. 1 shows a schematic configuration of the present invention.

(Embodiment 1)
Embodiments of the present invention generally generate electric power and can output hot water warmed by exhaust heat generated by the generation of the electric power, store hot water from the fuel cell, and supply the hot water to the outside A hot water storage tank that can be discharged into the hot water tank, at least first and second thermometers that measure the temperature of hot water in the hot water tank, and a hot water tank that is obtained based on the temperature measurement values measured by the thermometers. A fuel cell power generation system comprising: means for setting a power generation output of the fuel cell according to a heat storage amount.

This will be specifically described below. In the present embodiment, the heat of the fuel cell 1 is supplied to the hot water tank 3 through the pipe (hot water supply path) 4 in the form of hot water by the heat recovery heat exchanger 2 to store the hot water. The hot water in the hot water tank 3 is required by opening a valve (not shown) provided in a part of a discharge pipe (hot water supply path to the user side) 5 whose one end is connected to the upper part of the hot water tank 3. An amount to be taken out can be taken out of the hot water tank 3. Further, for example, a pipe 7 for supplying tap water is communicated with the bottom of the hot water tank 3, and when the hot water in the hot water tank 3 is used, the amount of water corresponding to the amount of use is replenished. ing. The configuration so far is the same as the conventional one.

  Here, a thermometer 6 described below and a microcomputer, for example, are included, and a power generation output changing means (control device) 8 for setting the power generation output of the fuel cell 1 is newly added and configured as follows. . That is, the thermometer 6 is a commercially available ordinary one that measures the temperature of the hot water in the hot water tank 3, and the hot water tank 3 is virtually arranged in the vertical direction at, for example, a temperature boundary position (here, Are arranged so that the temperature of the hot water can be measured corresponding to the virtual divided space.

  The thermometer 6 measures the temperature of the hot water in the hot water tank 3 and virtually divides the hot water tank 3 into at least two parts in the vertical direction, and the temperature of the hot water corresponding to each virtual divided space. It consists of at least first and second thermometers that respectively measure.

  The power generation output changing means (control device) 8 inputs the measured values of the thermometer 6, and the measured value of the first thermometer 6 is calculated from the temperature on the hot water supply side supplied from the fuel cell 1 into the hot water tank 3. A low first set value, for example, 55 ° C. or less, and a measured value of the second thermometer 6 is lower than the first set value, and a second set value, for example, 40 ° C., which approximates a cooling temperature that the fuel cell 1 can tolerate. At the following time, the upper limit value of the power generation output of the fuel cell 1 is changed.

  3 and 4 are diagrams showing a relationship between the first and second temperature set values and the battery output, and a diagram showing a relationship between the temperature, the battery output and time.

  Thus, the heat generated in the fuel cell 1 is stored in the hot water tank 3. The stored hot water is supplied to consumers. As a result, the following effects can be obtained.

  (1) Even when there is little demand for hot water supply such as in summer, and there is much demand for power, the operation of the fuel cell power generator can be continued as much as possible, and the economy and energy saving can be improved.

  (2) To provide a fuel cell power generation system capable of determining the power generation output capable of operating the fuel cell power generation device and starting and stopping according to the real-time heat demand of the customer. By stopping the fuel cell 1 promptly, it is possible to improve economic efficiency and energy saving and improve safety.

  The power generation output changing means (control device) 8 has a function of stopping the power generation operation of the fuel cell 1 when the measured value of the second thermometer 6 exceeds the second set value in the above-described embodiment. It may be added.

  In addition, the power generation output changing means (control device) 8 described above has a function of calculating the amount of change in the temperature measurement value per fixed time in the embodiment described above, and the obtained amount of change is a preset change. A function of stopping the power generation operation of the fuel cell may be added when the preset time is maintained below the amount.

  Furthermore, in the above-described embodiment, the power generation output changing means (control device) 8 takes in the measurement value of the second thermometer and sets the temperature measurement value in advance even when the fuel cell 1 is stopped. When the value is less than or equal to the value, a function of resuming the operation of the fuel cell 1 may be added.

  Further, the power generation output changing means (control device) 8 described above grasps the number of times of starting and stopping the fuel cell 1 in the above-described embodiment, and when the number of times of starting and stopping exceeds a preset value, the fuel cell. A protection function may be added to disable the activation of.

  In the above-described embodiment, the example in which the measured value of the thermometer 6 that is substantially proportional to the heat storage amount is input as the input of the power generation output changing means (control device) 8 has been described. Even if the amount of stored heat (the amount of heat in the hot water storage tank) is taken in, the same effect as in the above-described embodiment can be obtained.

The power generation output changing means (control device) 8 is based on the temperature measurement values T1 to T2 measured by the thermometers 6, the outside air temperature T6, and the volumes of hot water R1 to R2 in the hot water storage tank 3, and in the hot water storage tank 3. The amount of heat in the hot water tank is calculated for each virtual divided space, and the amount of heat _Qhw in the hot water tank in the entire hot water tank is calculated from the sum of these.

  Specifically, the calculation is performed according to equation (1).

Q _hw = R1 × (T1-T6) + R2 × ((T1 + T2) / 2−T6) (1) where Q _hw is the amount of heat in the hot water tank
Rn: Volume (R1-R2)
Tn: Temperature measurement value (for example, T1 to T2)
T6: Outside air temperature Further, the battery exhaust heat amount calculation means includes temperature measurement values TI and TO of hot water measured by thermometers 9 and 10 provided on the inlet side and the outlet side of the cooling water pipe of the fuel cell 1, respectively, and fuel The amount of exhaust heat dQ _FC from the fuel cell is obtained from the flow rate in the cooling water piping of the battery 1. In this case, the flow rate is obtained, for example, by monitoring the number of revolutions of the pump 8 provided in a part of the cooling water pipe every predetermined time, for example, every 5 seconds, and calculating the integrated value thereof.

Apart from this, the amount of exhaust heat dQ _FC can also be obtained by equation (2).

dQ _FC = dW × A (2) where dW: fuel cell power generation A: thermoelectric ratio (fuel cell power generation and exhaust heat ratio)
Further, the hot water tank heat quantity change calculating means calculates the heat quantity change dQ _hw in the hot water tank every predetermined time from the calculated value calculated by the hot water tank heat quantity calculating means.

In the arithmetic unit 7 having such a configuration, the hot water storage tank is combined with the heat quantity change dQ _{hw in the} hot water tank and the exhaust heat quantity dQ _FC supplied from the fuel cell 1 to the hot water tank 3 according to the equation (3). It is possible to accurately estimate the heat demand dQ _user from the _user to the _user side.

dQ _user = dQ _hw + dQ _FC (3) Formula FIG. 2 is a diagram for explaining the above description, (a) is a calorific characteristic from the fuel cell 1 to the hot water tank 3, and (b) is The amount of heat in the hot water tank at each hour, (c) shows the heat demand characteristic on the use side from the hot water tank 3.

The schematic block diagram which shows embodiment of this invention. (a) is a calorific value characteristic from the fuel cell 1 to the hot water tank 3, (b) is a calorific value characteristic in the hot water tank every hour, and (c) is a heat demand characteristic on the use side from the hot water tank 3. Figure. The figure for demonstrating the function of the control apparatus of embodiment of FIG. The figure for demonstrating the function of the control apparatus of embodiment of FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Fuel cell, 2 ... Heat recovery heat exchanger, 3 ... Hot water tank, 4 ... Piping, 5 ... Discharge piping, 7 ... Piping, 8 ... Power generation output change means (control device)

Claims (6)

A fuel cell capable of generating electric power and outputting hot water warmed by exhaust heat generated by the generation of the electric power;
A hot water storage tank for storing hot water from the fuel cell and discharging the hot water to the outside;
At least first and second thermometers for measuring the temperature of hot water in the hot water tank;
Means for setting the power generation output of the fuel cell in accordance with the amount of heat stored in the hot water tank obtained based on the temperature measurement value measured by each thermometer;
Fuel cell power generation system equipped with. A fuel cell capable of generating electric power and outputting hot water warmed by exhaust heat generated by the generation of the electric power;
A hot water storage tank for storing hot water from the fuel cell and discharging the hot water to the outside;
The temperature of the hot water in the hot water tank is measured, the hot water tank is virtually divided into at least two in the vertical direction, and the temperature of the hot water is measured corresponding to each virtual divided space. At least first and second thermometers;
The first and second thermometer measurement values are input, and the first thermometer measurement value is lower than the temperature of the hot water supply side supplied from the fuel cell into the hot water tank. And when the measured value of the second thermometer is lower than the first set value and lower than or equal to a second set value that approximates a cooling temperature that the fuel cell can tolerate, Power generation output changing means for changing the upper limit value;
Fuel cell power generation system equipped with.   3. The fuel according to claim 2, wherein the power generation output changing means has a function of stopping the power generation operation of the fuel cell when a measured value of the second thermometer exceeds the second set value. Battery power generation system.   The power generation output changing means has a function of calculating the amount of change in the temperature measurement value per fixed time, and when the obtained amount of change continues below a preset amount of change for a preset time, 3. The fuel cell power generation system according to claim 2, wherein the fuel cell power generation system has a function of stopping power generation operation of the fuel cell.    The power generation output changing means takes in the measured value of the first thermometer even when the fuel cell is stopped, and when the measured temperature value is equal to or lower than a preset value, the fuel cell The fuel cell power generation system according to claim 2, wherein the fuel cell power generation system has a function of restarting the operation.   The power generation output changing means has a protection function for grasping the number of times of starting and stopping the fuel cell and prohibiting the starting of the fuel cell power generation facility when the number of times of starting and stopping is equal to or greater than a preset value. Item 3. The fuel cell power generation system according to Item 2.

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