Fuel cell device

Abstract

To provide a fuel cell device capable of efficiently suppressing freezing of water in a flow path while suppressing internal power consumption.SOLUTION: A fuel cell device includes a fuel cell, a first heat exchanger for performing heat-exchange between exhaust heat of the fuel cell and a heat medium, a heat storage tank for storing the heat medium, a first circulation path in which the heat medium circulates between the heat storage tank and the first heat exchanger, a first circulation pump for circulating the heat medium in a first circulation path, a second circulation path provided independently of the first circulation path, a second circulation pump provided in the second circulation path, and a control device. The control device executes freezing suppression control for controlling the operation of the first circulation pump and the second circulation pump based on the outside air temperature and / or the temperature of the heat medium.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present disclosure relates to fuel cell devices. [Background technology]

[0002] The fuel cell device generates electricity using a raw fuel gas containing hydrogen and an oxygen-containing gas (air) and supplies the electricity to the outside. The fuel cell device also forms part of a cogeneration system that recovers heat from the exhaust gas generated by power generation and the combustion of surplus gas, stores it as hot water, and supplies the hot water directly or indirectly to the outside.

[0003] Fuel cell devices use or store a large amount of water, and therefore are equipped with a function for preventing or suppressing the freezing of the water flowing or circulating inside the exterior case. For example, Patent Document 1 discloses a fuel cell device that prevents the water in the circulation flow path from freezing by using hot water stored in a hot water tank without adding a heater or other heating device.

[0004] Furthermore, cited document 2 discloses a method for effectively preventing freezing of water in a flow path in a fuel cell device having a heater or other heating device in the flow path when the temperature of the flow path is below a predetermined value, by heating the water in the flow path with the heater and circulating the heated water throughout the entire flow path with a pump, without providing a heater over a wide area. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2004-60980 A [Patent Document 2] JP 2008-32320 A Summary of the Invention [Problem to be solved by the invention]

[0006] An object of the present disclosure is to provide a fuel cell device that can efficiently prevent water in the flow passages from freezing while suppressing internal power consumption. [Means for solving the problem]

[0007] The fuel cell device of the present disclosure includes a fuel cell, a first heat exchanger that exchanges heat between exhaust heat from the fuel cell and a heat medium, a heat storage tank that stores the heat medium, a first circulation path through which the heat medium circulates between the heat storage tank and the first heat exchanger, a first circulation pump that circulates the heat medium in the first circulation path, a second circulation path that is provided independently of the first circulation path and that circulates the heat medium in the heat storage tank, and a second circulation pump that circulates the heat medium in the second circulation path. Scripture The circulation system further includes a second circulation pump provided in the passage and a control device. The control device is capable of executing anti-freezing control for controlling the operation of the first circulation pump and the second circulation pump based on an outside air temperature and / or a temperature of the heat medium, and is configured to perform a first temperature determination for determining whether the outside air temperature is higher than a predetermined first outside air temperature. Determine and, if the outside air temperature does not satisfy the first temperature judgment, executing a first freeze suppression control to start or maintain operation of the first circulation pump and maintain operation of the second circulation pump. After executing the first freeze suppression control, a second temperature judgment is performed including a first step of determining whether the outside air temperature is equal to or higher than a second outside air temperature set higher than the first outside air temperature and a second step of determining whether the temperature of the heat medium is higher than a predetermined first heat medium temperature. If the second temperature judgment is not satisfied, executing a second freeze suppression control to increase driving of the first circulation pump and the second circulation pump. After executing the second freeze suppression control, a third temperature judgment is performed including a first step of determining whether the outside air temperature is equal to or higher than the second outside air temperature, a second step of determining whether the temperature of the heat medium is equal to or higher than a second heat medium temperature set higher than the first heat medium temperature, and a third step of determining whether the temperature of the heat medium is higher than the first heat medium temperature. Effect of the Invention

[0008] According to the fuel cell device of the present disclosure, it is possible to efficiently prevent water in the flow passages from freezing while suppressing internal power consumption. [Brief description of the drawings]

[0009] [Figure 1] 1 is a schematic diagram of a fuel cell device according to an embodiment; [Diagram 2] FIG. 2 is an enlarged view of a heat medium circulation system in the fuel cell device. [Diagram 3] FIG. 2 is a perspective view showing the configuration of the fuel cell device inside the exterior case. [Figure 4] 4 is a flowchart relating to anti-freezing control. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, an embodiment will be described with reference to the drawings.

[0011] Fig. 1 is a block diagram showing an outline of the configuration of a fuel cell device according to an embodiment, and Fig. 2 is an enlarged view of a main part of Fig. 1. Note that detailed explanations of general-purpose devices and equipment in the fuel cell device are not provided, and some are merely indicated by reference numerals in the drawings.

[0012] The fuel cell device 100 shown in FIG. 1 comprises a fuel cell module 1 accommodated in a storage container 10, a heat exchanger (first heat exchanger 2) connected to the fuel cell module 1, a heat storage tank 3 that recovers heat and thermal energy of the high-temperature exhaust gas discharged from the fuel cell module 1 through heat exchange and stores it as hot water, and a reforming water tank 6 that stores condensed water produced when moisture contained in the exhaust gas is condensed through heat exchange as reforming water.

[0013] The fuel cell device 100 also includes a raw fuel supply device including a raw fuel pump B1 and a raw fuel flow path, etc., and an oxygen-containing gas supply device including an air blower B2 and an oxygen-containing gas flow path, etc. Furthermore, the fuel cell device 100 includes a reforming water supply device including a condensed water flow path C, the above-mentioned reforming water tank 6, the reforming water supply pump P3, and the reforming water flow path R in order to continue water independent operation.

[0014] As shown in FIG. 2, the fuel cell device 100 is equipped with a heat medium circulation system (first heat cycle) consisting of the first heat exchanger 2, the heat storage tank 3, the radiator 4, the heat medium circulation pump P1, and a heat medium circulation flow path HC1 that connects these in a circular manner.

[0015] The fuel cell device 100 also includes a hot water supply system (second heat cycle) including a second heat exchanger 5 for heating tap water (clean water) to be supplied to the outside, and a water circulation pump P2 and a water circulation flow path HC2 for extracting and circulating a high-temperature heat transfer medium from the aforementioned heat storage tank 3.

[0016] Of the two heat exchangers, the first heat exchanger 2, also called the main heat exchanger or latent heat exchanger, is for exchanging heat between the exhaust heat of the fuel cell module 1 that houses the fuel cell cells and the heat medium (in this example, water as a heat medium or refrigerant). Note that a heater for preventing freezing or a heater that consumes surplus power that is energized during independent operation may be disposed on the heat medium circulation flow path HC1, which is the first heat cycle.

[0017] In addition, in the enlarged view of Figure 2, the illustration of components that are not used in the embodiment, such as a water supply flow path (piping) for supplying or refilling external water such as tap water to the heat storage tank 3, an overflow flow path for discharging water when the tank is overfull, a tap water inlet Win and a hot water outlet Wout for external hot water supply, are simplified.

[0018] The fuel cell device 100 is disposed in a case 30 consisting of frames 31 and exterior panels 32, as shown in Fig. 3. In this embodiment, at least the fuel cell module 1, the first heat exchanger 2, the second heat exchanger 5, the heat storage tank 3, the heat medium circulation flow path HC1 and the heat medium circulation pump P1, and the water circulation flow path HC2 and the water circulation pump P2 are housed in this case 30. In addition, around the module and each auxiliary device, in the flow paths, piping, etc., a control device 20, a plurality of measuring instruments and sensors, or other auxiliary devices, as described below, are provided.

[0019] The fuel cell device 100 includes a power conditioning device (not shown) as a means for controlling the operation of the aforementioned fuel cell module 1 and each auxiliary device, a control device 20 that works in conjunction with this power conditioning device to control the operation of each auxiliary device that assists in the power generation operation of the fuel cell, and a memory device attached to or built into this control device 20.

[0020] The control device 20 is connected to a storage device and a display device (both not shown) and to various components and sensors that make up the fuel cell device 100, and controls and manages these functional units as well as the entire fuel cell device 100. The control device 20 obtains programs stored in an associated storage device (not shown) and executes these programs to realize various functions associated with each unit of the fuel cell device 100.

[0021] The fuel cell device 100 includes a plurality of temperature measuring devices or thermometers, such as temperature sensors and thermistors, for measuring the temperatures of various parts inside and outside the casing.

[0022] For example, as shown in Figures 1 and 2, a thermistor TM2 is disposed on the heat medium circulation flow path HC1 to measure the temperature of the heat medium (water) immediately before it is introduced from the heat medium inlet on the lower side of the first heat exchanger 2.

[0023] The thermistor TM2 is an example of a second temperature measurement unit in the present disclosure. Also, like the thermistor TM1 in the figure, a first temperature measurement unit for measuring the outside air temperature outside the device is provided.

[0024] When the control device 20 transmits control signals or various information to other functional units or devices, the control device 20 and the other functional units may be connected by wire or wirelessly. In each drawing, the illustration of the connection lines connecting the control device 20 to each device and each sensor constituting the fuel cell may be omitted. In addition, the control characteristic of this embodiment performed by the control device 20 will be described later.

[0025] In the embodiment described below, the control device 20 controls the on / off duty ratio and the rotation speed of the rotary drive motor according to the type of the heat medium circulating pump P1 and the water circulating pump P2, thereby adjusting the drive force and discharge amount of the heat medium circulating pump P1 and the water circulating pump P2.

[0026] In the fuel cell device 100 configured as above, when the main power supply (breaker) of the fuel cell device is on, the control device 20 constantly checks the outside air temperature TH1 (°C) measured by the thermistor TM1 (first temperature measurement unit), regardless of whether the fuel cell is generating electricity or not. Each of the freeze suppression controls and temperature determination controls will be explained below in order.

[0027] 4 is a flowchart of the anti-freezing control and the temperature determination control in this embodiment. Note that in the flowchart, each "step" is abbreviated as "S."

[0028] First, in [S1], a first temperature judgment is made to judge whether the outside air temperature TH1 measured by the thermistor TM1 (first temperature measurement unit) is higher than a predetermined first outside air temperature X1 (°C). The first outside air temperature X1 can be set to a temperature of, for example, about 1 to 10°C, and is set to 6°C in this example.

[0029] That is, when the first temperature condition is not satisfied, i.e., specifically, when the outside air temperature TH1 is compared with the first outside air temperature X1 (S1), and the result is [NO] that the outside air temperature TH1 is lower than the first outside air temperature X1, the control device 20 performs a first freeze suppression control in (S2), which controls the operation of the heat medium circulation pump P1 (first circulation pump) and the water circulation pump P2 (second circulation pump).

[0030] Specifically, when the heat medium circulation pump P1 is operating, the control device 20 controls the heat medium circulation pump P1 to maintain its operating state, and when the heat medium circulation pump P1 is stopped, the control device 20 controls the heat medium circulation pump P1 to start operating.

[0031] The control device 20 also controls the water circulation pump P2 to maintain its operating state. That is, when the water circulation pump P2 is operating, the control device 20 maintains the operating state, and when the water circulation pump P2 is stopped, the control device 20 controls the pump to remain stopped. Note that in this embodiment, even when the control device 20 does not directly change the operating state of the pump, that is, when the control device 20 maintains the state, it is considered that the control device 20 is controlling the operation of the pump.

[0032] The heat medium circulating pump P1 and the water circulating pump P2 may be driven by controlling the drive of each pump. That is, the discharge rate from each pump may be controlled to increase or decrease. Therefore, in addition to controlling the rotation speed, the duty ratio of the motor drive, which is the driving force of the pump, may be adjusted.

[0033] Next, after executing the first anti-freeze control, the control device 20 performs a second temperature determination, which includes a first step [S3] of determining whether the outside air temperature TH1 is equal to or higher than a second outside air temperature X2 (°C) that is set higher than the first outside air temperature X1, and a second step [S4] of determining whether the heat medium temperature TH2 (second measured temperature) measured by thermistor TM2 (second temperature measurement unit) is higher than a predetermined first heat medium temperature Y1 (°C).

[0034] Note that, between each step, there may be a time interval of several minutes to several tens of minutes to wait for the pump discharge rate to stabilize or for the water temperature or other temperature to stabilize, but this is not shown in the flowchart. The same applies to the following control flows.

[0035] In the second temperature judgment, if the outside air temperature TH1 is equal to or higher than the second outside air temperature X2 (YES in [S3]), the process proceeds to [S13], where the drive of the heat medium circulation pump P1 is reduced and the drive of the water circulation pump P2 is stopped, and this control ends (END). The second outside air temperature X2 can be set to a temperature of, for example, about 1 to 15°C, and is set to 8°C in this example.

[0036] On the other hand, in the second temperature judgment, if the outside air temperature TH1 is lower than the second outside air temperature X2 (if [NO] in [S3]), the process proceeds to the second step [S4], where it is judged whether the heat medium temperature TH2 is higher than the first heat medium temperature Y1. Here, if the heat medium temperature TH2 is higher than the first heat medium temperature Y1, the process returns to [S3]. Note that the first heat medium temperature Y1 The temperature can be set, for example, at about 1 to 10°C, and is set to 6°C in this example.

[0037] Proceeding to the second step [S4], if the heat medium temperature TH2 is equal to or lower than the first heat medium temperature Y1 (in other words, if both of the second temperature judgments [S3] and [S4] are not satisfied), the control device 20 proceeds to [S5] and executes a second anti-freeze control that increases the drive of each pump more than the first anti-freeze control.

[0038] In the second anti-freezing control, the controller 20 executes control to increase the drive of the heat medium circulating pump P1 and the water circulating pump P2 compared to the drive in the first anti-freezing control. This makes it possible to further suppress freezing in addition to the first anti-freezing control.

[0039] Next, after executing the second anti-freeze control, the control device 20 performs a third temperature determination, which includes a first step [S6] of determining whether the outside air temperature TH1 is equal to or higher than a second outside air temperature X2 that is set higher than the first outside air temperature X1, a second step [S7] of determining whether the heat medium temperature TH2 is equal to or higher than a second heat medium temperature Y2 (°C) that is set higher than the first heat medium temperature Y1, and a third step [S8] of determining whether the heat medium temperature TH2 is higher than the first heat medium temperature Y1.

[0040] In the third temperature judgment, if the outside air temperature TH2 is higher than or equal to the second outside air temperature X2 (YES in [S6]), proceed to [S13] as in the first step of the second temperature judgment, reduce the drive of the heat medium circulation pump P1 and stop the drive of the water circulation pump P2, and terminate this control .

[0041] On the other hand, in the third temperature judgment, if the outside air temperature TH1 is less than the second outside air temperature X2 (if [NO] in [S6]), the process proceeds to the second step [S7], where it is judged whether the heat medium temperature TH2 is equal to or higher than the second heat medium temperature Y2 set higher than the first heat medium temperature Y1. If the heat medium temperature TH2 is equal to or higher than the second heat medium temperature Y2, the risk of freezing is slightly reduced, so the process proceeds to [S9], the operation of the water circulation pump P2 is stopped, and the process returns to [S2]. That is, the operation of the heat medium circulation pump P1 is also reduced. The second heat medium temperature Y2 can be set to a temperature of, for example, about 1 to 25°C, and is set to 18°C ​​in this example.

[0042] On the other hand, in the second step [S7], if the heat medium temperature TH2 is less than the second heat medium temperature Y2 (if [S7] is NO), the process proceeds to the third step [S8], where it is determined whether the heat medium temperature TH2 is higher than the first heat medium temperature Y1. If the heat medium temperature TH2 is higher than the first heat medium temperature Y1, the process returns to [S6].

[0043] Proceeding to the third step [S8], if the heat medium temperature TH2 is equal to or lower than the first heat medium temperature Y1 (in other words, if none of the third temperature judgments [S6], [S7] and [S8] are satisfied), the control device 20 proceeds to [S10] and executes a third anti-freeze control that increases the drive of each pump more than the second anti-freeze control.

[0044] In the third anti-freeze control, the control device 20 executes control to increase the drive of the heat medium circulating pump P1 and the water circulating pump P2 compared to the drive in the second anti-freeze control. This makes it possible to further suppress freezing in addition to the first anti-freeze control and the second anti-freeze control. Note that the drive of the heat medium circulating pump P1 and the water circulating pump P2 in the third anti-freeze control can be set to the maximum drive of each pump.

[0045] Next, after executing the third anti-freeze control, the control device 20 performs a fourth temperature determination, which includes a first step [S11] of determining whether the outside air temperature TH1 is less than a second outside air temperature X2 that is set higher than the first outside air temperature X1, and a second step [S12] of determining whether the heat medium temperature TH2 is equal to or higher than a third heat medium temperature Y3 (°C) that is set higher than the first heat medium temperature Y1.

[0046] In the fourth temperature judgment, if the outside air temperature TH1 is equal to or higher than the second outside air temperature X2 (if [NO] in [S11]), proceed to [S13], as in the first step of the second temperature judgment and the first step of the third temperature judgment, reduce the drive of the heat medium circulation pump P1 and stop the drive of the water circulation pump P2, and terminate this control .

[0047] On the other hand, in the fourth temperature judgment, if the outside air temperature TH1 is lower than the second outside air temperature X2 (YES in [S11]), the process proceeds to a second step [S12] to judge whether the heat medium temperature TH2 is equal to or higher than a third heat medium temperature Y3 set higher than the first heat medium temperature Y1. If the heat medium temperature TH is lower than the third heat medium temperature Y3, the process returns to [S11].

[0048] On the other hand, in the second step [S12], if the heat medium temperature TH2 is equal to or higher than the third heat medium temperature Y3, the risk of freezing is slightly reduced, so the process proceeds to [S5] and the operation of the heat medium circulating pump P1 and the water circulating pump P2 is reduced. The third heat medium temperature Y3 can be set to a temperature of, for example, 1 to 25°C, but can also be set lower than the second heat medium temperature Y2, and is set to 15°C in this example.

[0049] As described above, according to the configuration of this embodiment, it is possible to efficiently prevent the water in the flow path from freezing while suppressing an increase in internal power consumption, such as by heating the water in the flow path with a heater to prevent freezing.

[0050] The above anti-freezing control of the fuel cell device is based on the assumption that a low temperature environment occurs during normal power generation operation, but when the fuel cell device is in an independent operation state where it is disconnected from the grid power supply and generates power by itself, the driving force of the second circulation pump (water circulation pump P2) arranged in the second circulation flow path (water circulation flow path HC2) is limited to a predetermined value or less in order to suppress the overall power consumption.Other than that, it is the same as during normal power generation operation described above. [Explanation of symbols]

[0051] 1 Fuel Cell Module 2 1st heat exchanger 3. Heat storage tank 20 Control device 100 Fuel cell equipment P1 Heat transfer medium circulation pump (first circulation pump) P2 Water Circulation Pump (Second Circulation Pump) HC1 Heat transfer medium circulation channel (first circulation channel) HC2 Water circulation flow path (second circulation flow path) TM Thermistor

Claims

1. A fuel cell; a first heat exchanger for exchanging heat between the exhaust heat of the fuel cell and a heat medium; A heat storage tank that stores the heat medium; a first circulation path through which the heat medium circulates between the heat storage tank and the first heat exchanger; a first circulation pump that circulates the heat medium through the first circulation path; a second circulation path provided independently of the first circulation path and configured to circulate the heat medium in the heat storage tank; a second circulation pump provided in the second circulation path; A control device, the control device is capable of executing anti-freezing control for controlling operation of the first circulating pump and the second circulating pump based on an outside air temperature and / or a temperature of the heat medium; performing a first temperature determination to determine whether the outside air temperature is higher than a predetermined first outside air temperature; When the outside air temperature does not satisfy the first temperature determination, a first anti-freezing control is executed to start or maintain the operation of the first circulating pump and maintain the operation of the second circulating pump; After the first anti-freezing control is executed, A first step of determining whether an outside air temperature is equal to or higher than a second outside air temperature set higher than the first outside air temperature; a second step of determining whether the temperature of the heat medium is higher than a predetermined first heat medium temperature; When the second temperature determination is not satisfied, a second anti-freezing control is executed to increase the driving of the first circulating pump and the second circulating pump; After the second anti-freezing control is executed, a first step of determining whether an outside air temperature is equal to or greater than the second outside air temperature; a second step of determining whether the temperature of the heat medium is equal to or higher than a second heat medium temperature set higher than the first heat medium temperature; and a third step of determining whether the temperature of the heat medium is higher than the first heat medium temperature.

2. 2. The fuel cell device according to claim 1, wherein the control device stops driving the second circulation pump when a second step in the third temperature determination is satisfied.

3. 2. The fuel cell device according to claim 1, wherein the control device executes a third anti-freezing control for increasing driving of the first circulation pump and the second circulation pump when the third temperature determination condition is not satisfied.

4. After executing the third anti-freezing control, the control device a first step of determining whether an outside temperature is less than the second outside temperature; 4. The fuel cell device according to claim 3, further comprising a second step of determining whether the temperature of the heat medium is equal to or higher than a third heat medium temperature set higher than the first heat medium temperature.

5. 5. The fuel cell device according to claim 4, wherein the control device executes control to reduce driving of the first circulation pump and the second circulation pump when the fourth temperature determination condition is met.

6. 2. The fuel cell device of claim 1, wherein the control device, after performing a third freeze prevention control that increases the drive of the first circulation pump and the second circulation pump when the second temperature determination, the third temperature determination, and the third temperature determination are not satisfied, reduces the drive of the first circulation pump and stops the operation of the second circulation pump when the outside air temperature is equal to or higher than the second outside air temperature in a fourth temperature determination that includes a first step of determining whether the outside air temperature is lower than the second outside air temperature and a second step of determining whether the temperature of the heat medium is equal to or higher than a third heat medium temperature that is set higher than the first heat medium temperature.

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