Power generation unit

Abstract

To provide a power generation unit which can increase / decrease power capable of being supplied from an autonomous outlet used in a power failure of a commercial power supply system in response to the requests of a consumer, and can enhance convenience in emergency.SOLUTION: A power generation unit 100 is operated in a parallel state or a parallel-off state with a commercial power supply system 500, and includes: a power generation module 20; a power conditioner 16; a controller 17; an autonomous outlet 300 for supplying a part of generated power of the power generation module 20 to power use equipment in the parallel-off state; and a first load module 40 for consuming a part of the generated power of the power generation module 20 therein, in the parallel-off state. The power generation unit 100 can select to further include a second load module 50 for consuming a part of the generated power of the power generation module 20 therein, in the parallel-off state, in response to the needs of a power consumer.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a power generation unit using a fuel cell or the like.

Background Art

[0002] By switching a part of the commercial power purchased by a consumer from a power utility to self-generated power, it is expected to lead to a reduction in carbon dioxide emissions. For example, the primary energy efficiency of thermal power generation using coal or LNG as fuel is about 40%, whereas the primary energy efficiency of a solid oxide fuel cell (SOFC) that generates power by reforming city gas mainly composed of methane can be expected to be 50% to 65%. Therefore, increasing the proportion of self-generated power can contribute to reducing the environmental load.

[0003] In addition, by realizing a system that can maintain power supply independently when a power outage occurs due to a natural disaster, it is expected that the adverse effects on social life and economic activities can be reduced. For example, a solid oxide fuel cell (SOFC) can generate power independently and supply power to the outside as long as the supply of city gas is not interrupted. In the case of an earthquake, the gas infrastructure may be damaged depending on the scale, but in the case of a typhoon, it can be said that there is almost no impact on the gas infrastructure, so power supply can be continued.

[0004] Patent Documents 1 to 3 disclose a power generation unit (fuel cell unit) that operates in parallel with a commercial power supply system and supplies power to power demand facilities. During the operation of the power generation unit, reverse power flow to the commercial power supply system side is not allowed. Therefore, in the power generation units described in Patent Documents 1 and 2, the surplus generated power is consumed by an electric heater or the like.

[0005] In addition, the power generation unit described in Patent Document 3 is disconnected from the commercial power supply system to avoid reverse power flow during a power outage of the commercial power supply system and is switched to independent operation. When the power generation unit is disconnected, it cannot supply power to the power demand facilities. Therefore, the self-generated power is sent to a self-powered outlet to which power-consuming devices can be connected to meet the power needs of consumers.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0007] A general self-powered outlet has a plurality of plug sockets so that several power-consuming devices can be used simultaneously. However, the power consumption varies depending on the number of connected power-consuming devices and so on. Therefore, the independent operation power (output power) of the power generation unit is kept constant, and the surplus generated power is consumed by an electric heater or the like.

[0008] Incidentally, a power generation unit using a fuel cell or the like is generally configured to receive startup power during startup operation from a commercial power supply system. After shifting to independent operation, since the power generation unit cannot be stopped until the power outage is resolved, how to set the available power via the independent outlet during independent operation often troubles the device provider. For example, if the available power of the independent outlet is set to be the same as the rated output power of the power generation unit, when there is no connection of electrical equipment, all of the rated output power will be consumed by an electric heater or the like, and there is a concern that a lot of fuel will be wasted. On the contrary, if the available power of the independent outlet is set to be the same as the minimum output power of the power generation unit, although the power consumption of an electric heater or the like can be suppressed, there is a possibility that the power needs of the consumer cannot be sufficiently met.

[0009] The present invention has been made in view of the above problems, and an object thereof is to provide a power generation unit that can increase or decrease the available power of an independent outlet used during a power outage of a commercial power supply system according to the demands of consumers, and can enhance convenience in an emergency.

Means for Solving the Problems

[0010] The power generation unit according to the present invention is a power generation unit that operates in a parallel state or a disconnected state with respect to a commercial power supply system, and includes a power generation module operated by an auxiliary machine, a power conditioner that converts the generated power of the power generation module into output power corresponding to the AC power of the commercial power supply system, a controller that controls the power generation module and the auxiliary machine, an independent outlet that supplies a part of the generated power of the power generation module to electrical equipment during the disconnected state, and a first load module that internally consumes a part of the generated power of the power generation module during the disconnected state. The controller and the power conditioner are configured to operate in an interlinked operation mode in the parallel state and in an independent operation mode in the disconnected state. The power generation unit may further selectively include a second load module that internally consumes a part of the generated power of the power generation module during the disconnected state according to the power needs of consumers.

Advantages of the Invention

[0011] According to the present invention, it is possible to provide a power generation unit that can increase or decrease the available power of a self - contained power strip used during a power outage in a commercial power supply system according to the demands of consumers, thereby enhancing convenience in an emergency.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Modes for Carrying Out the Invention

[0013] Hereinafter, each embodiment of the present invention will be described with reference to the respective drawings.

[0014] 〔First Embodiment〕 <Configuration Outline of the Power Generation Unit> First, the configuration outline of the power generation unit according to the first embodiment will be described. FIG. 1 is a schematic diagram showing the configuration of the power generation unit according to the first embodiment. As shown in FIG. 1, the power generation unit 100 is a monogeneration type using a fuel cell, and includes a plurality of cell stacks 1, a reformer 2, a burner 3, an evaporator 4, an air preheater 5, an anode off - gas cooler 6, an anode off - gas condenser 7, a CO oxidizer (carbon monoxide oxidizer) 8, a condensate recovery tank 9, a first raw fuel blower 10, a first air blower 11, a water pump 12, a second raw fuel blower 13, a second air blower 14, a third air blower 15, a power conditioner 16, and a unit controller 17.

[0015] In addition, in the example of this embodiment, a total of eight cell stacks 1 are provided, including those whose illustration is omitted in FIG. 1.

[0016] The power generation unit 100 also includes lines (pipe lines) such as a raw fuel line La, a mixed gas line Lb, an anode fuel line Lc, an anode off-gas line Ld, a cathode air line Le, a cathode off-gas line Lf, a combustion gas line Lg, a burner cooling air line Lh, a reformed water line Li, a startup air line Lj, a cooling air line Lk, and a condensate recovery line Lw.

[0017] The anode fuel line Lc includes a first distribution manifold Ma that serves as a main pipe for introducing anode fuel, and the cathode air line Le includes a second distribution manifold Mb that serves as a main pipe for introducing cathode air. These distribution manifolds Ma and Mb have an inlet and a plurality of outlets corresponding to each cell stack 1, and cause the fluid flowing into the inlet to flow out from each outlet.

[0018] The anode off-gas line Ld includes a first collection manifold Mc that serves as a main pipe for discharging anode off-gas, and the cathode off-gas line Lf includes a second collection manifold Md that serves as a main pipe for discharging cathode off-gas. These collection manifolds Mc and Md have a plurality of inlets and outlets corresponding to each cell stack 1, and cause the fluid flowing into each inlet to flow out from the outlet.

[0019] The combustion gas line Lg includes a heat radiation cylinder Za and a combustion gas pipe Zb. The cooling air line Lk includes a cooling pipe Zc and a collection pipe Lk1.

[0020] The raw fuel line La is a pipe line connecting the fuel intake port E1 and the burner 3, and a second raw fuel blower 13 is arranged in this pipe line. The second raw fuel blower 13 is a device that boosts the raw fuel gas Gf (for example, methane-containing gas such as city gas 13A) taken in from the fuel intake port E1 and sends it to the downstream side of the raw fuel line La. Typically, it is driven during the startup operation of the power generation unit 100.

[0021] The mixed gas line Lb is a pipeline connecting the fuel inlet E2 and the reformer 2. In this pipeline, in order from the upstream side, a first raw fuel blower 10, an evaporator 4, and a first bellows type expansion joint B1 are arranged. The first raw fuel blower 10 is a device that boosts the raw fuel gas Ga taken in from the fuel inlet E2 and sends it to the downstream side of the mixed gas line Lb, and is typically driven during the power generation operation of the power generation unit 100.

[0022] The anode fuel line Lc is a pipeline connecting the reformer 2 and the anode of each cell stack 1. More specifically, the anode fuel line Lc includes, in order from the upstream side, a pipeline connecting the reformer 2 and the inlet of the first distribution manifold Ma, the first distribution manifold Ma, and eight pipelines (the branch pipes of the first distribution manifold Ma) connecting each outlet of the first distribution manifold Ma and the anode of each cell stack 1.

[0023] The anode off-gas line Ld is a pipeline connecting the anode of each cell stack 1 and the burner 3. More specifically, the anode off-gas line Ld includes, in order from the upstream side, eight pipelines (the branch pipes of the first collection manifold Mc) connecting the anode of each cell stack 1 and each inlet of the first collection manifold Mc, the first collection manifold Mc, and a pipeline connecting the outlet of the first collection manifold Mc and the burner 3 (hereinafter referred to as "pipeline Ld1"). In the middle of the pipeline Ld1, in order from the upstream side, a second bellows type expansion joint B2, an anode off-gas cooler 6, an anode off-gas condenser 7, and a gas-liquid separation section Sa are arranged.

[0024] The cathode air line Le is a pipe connecting the air intake E3 and the cathode of each cell stack 1. More specifically, the cathode air line Le includes, in order from the upstream side, a pipe connecting the air intake E3 and the inlet of the second distribution manifold Mb (hereinafter referred to as "pipe Le1"), the second distribution manifold Mb, and eight pipes (the branch pipes of the second distribution manifold Mb) connecting each outlet of the second distribution manifold Mb and the cathode of each cell stack 1.

[0025] In the middle of the pipe Le1, in order from the upstream side, a first air blower 11, an anode off-gas cooler 6, an air preheater 5, and a third bellows expansion joint B3 are arranged. The first air blower 11 is a device that pressurizes the air Aa taken in from the air intake E3 and sends it to the downstream side of the cathode air line Le, and is typically driven during the power generation operation of the power generation unit 100. Further, in the pipe Le1, a bypass path Le2 bypassing the anode off-gas cooler 6 and the air preheater 5 is provided so as to connect the midpoint between the air intake E3 and the anode off-gas cooler 6 and the midpoint between the air preheater 5 and the third bellows expansion joint B3.

[0026] The cathode off-gas line Lf is a pipe connecting the cathode of each cell stack 1 and the burner 3. More specifically, the cathode off-gas line Lf includes, in order from the upstream side, eight pipes (the branch pipes of the second collection manifold Md) connecting the cathode of each cell stack 1 and each inlet of the second collection manifold Md, the second collection manifold Md, and a pipe connecting the outlet of the second collection manifold Md and the burner 3 (hereinafter referred to as "pipe Lf1").

[0027] The combustion gas line Lg is a pipeline connecting the burner 3 and the gas outlet E6. More specifically, the combustion gas line Lg includes, in order from the upstream side, a heat radiation cylinder Za, a pipeline connecting the heat radiation cylinder Za and the combustion gas pipe Zb, the combustion gas pipe Zb, and a pipeline connecting the combustion gas pipe Zb and the gas outlet E6 (hereinafter referred to as "pipeline Lg1"). In the middle of the pipeline Lg1, in order from the upstream side, a fourth bellows type expansion joint B4, an air preheater 5, a CO oxidizer 8, and an evaporator 4 are arranged.

[0028] The burner cooling air line Lh is a pipeline connecting the pipeline Le1 and the starting air line Lj, and a flow rate adjusting means (such as an orifice) (not shown) is provided in this pipeline. More specifically, the burner cooling air line Lh branches at the midpoint of the pipeline Le1 connecting the first air blower 11 and the anode off-gas cooler 6, and merges into the starting air line Lj on the downstream side of the second air blower 14. It is configured such that a minute flow rate of air Ab flows toward the burner 3 when the first air blower 11 is driven.

[0029] The cooling air line Lk is a pipeline connecting the air intake E5 and a predetermined location of the pipeline Lg1 (a location between the evaporator 4 and the gas outlet E6). In this pipeline, in order from the upstream side, a third air blower 15 and a cooling pipe Zc are arranged. The third air blower 15 is a device that pressurizes the cooling air Ad taken in from the air intake E5 and sends it to the downstream side of the cooling air line Lk.

[0030] The reformed water line Li is a pipeline connecting the condensed water recovery tank 9 and the evaporator 4, and a water pump 12 is arranged in this pipeline. The water pump 12 is a device that sends the condensed water Wb stored in the condensed water recovery tank 9 as reformed water Wa to the downstream side of the reformed water line Li.

[0031] The starting air line Lj is a pipeline connecting the air intake E4 and the pipeline Lf1, and a second air blower 14 is arranged in this pipeline. The second air blower 14 is a device that pressurizes the air Ac taken in from the air intake E4 and sends it to the downstream side of the starting air line Lj, and is typically driven during the startup operation of the power generation unit 100.

[0032] The condensate recovery line Lw is a pipeline connecting the gas-liquid separation part Sa arranged in the middle of the pipeline Ld1 and the condensate recovery tank 9. The gas-liquid separation part Sa is a member that separates the condensate Wb generated in the anode off-gas condenser 7 from the anode off-gas Gd, and the separated condensate Wb flows down in the condensate recovery line Lw. The tip of the condensate recovery line Lw is opened to the gas phase part without being immersed in the aqueous phase part of the condensate recovery tank 9 so that the condensate amount does not increase or decrease due to the influence of the temperature of the stored condensate Wb. Note that the tip of the condensate recovery line Lw is not immersed in the aqueous phase part in order not to change the flow rate of the anode off-gas Gd sent to the burner 3. In particular, this configuration is effective when the anode off-gas Gd after separating the condensate Wb is recycled to the primary side of the cell stack or used for power generation in the subsequent cell stack. For the gas-liquid separation part Sa, for example, a T-shaped pipe with a straight pipe part arranged horizontally and a branch pipe part arranged downward is used. Also, a small-capacity cylindrical container erected in the vertical direction can be used as the gas-liquid separation part Sa.

[0033] The cell stack 1 is a power generation body composed of a solid oxide fuel cell (SOFC). The solid oxide fuel cell is a high-temperature operating fuel cell in which the solid electrolyte, anode, and cathode constituting the power generation cell are all ceramics, and a power generation unit in which a predetermined number of power generation cells are integrated via a metal interconnect material (also referred to as a separator material) is called a cell stack. The battery output of the cell stack 1 is supplied after being adjusted by the power conditioner 16.

[0034] The reformer 2 reforms the raw fuel gas Ga using steam, generates a reformed gas Gc, and sends it to the downstream side. The reformer 2 has a catalyst for steam reforming, reacts methane contained in the raw fuel gas Ga with steam, and generates a reformed gas Gc containing carbon monoxide and hydrogen. Although steam reforming is an endothermic reaction, the reformer 2 can stably generate the reformed gas Gc by heat supply from the burner 3.

[0035] The burner 3 burns the inflowing gas to generate heat and discharges the combustion gas Gg generated by combustion to the combustion gas line Lg. The evaporator 4 is a device that indirectly heat-exchanges the reforming water Wa and the combustion gas Gg (heat source fluid). By heat-exchanging with the combustion gas Gg, it evaporates the reforming water Wa and at the same time heats the raw fuel gas Ga.

[0036] Both the air preheater 5 and the anode off-gas cooler 6 are heat exchangers that indirectly heat-exchange a low-temperature fluid and a high-temperature fluid. The air preheater 5 serves to preheat the air Aa in the cathode air line Le by heat-exchanging with the combustion gas Gg, and the anode off-gas cooler 6 serves to cool the anode off-gas Gd by heat-exchanging with the air Aa in the cathode air line Le.

[0037] The anode off-gas condenser 7 uses a fan 7a to cool the anode off-gas Gd and condenses the water vapor contained in the anode off-gas Gd. Note that the anode off-gas condenser 7 of this embodiment is an air-cooled heat exchanger, but instead, a water-cooled heat exchanger may be adopted, and thus it may be a cogeneration type power generation unit in which heat recovery is performed.

[0038] The CO oxidizer (carbon monoxide oxidizer) 8 is a device that brings the harmful carbon monoxide contained in the combustion gas Gg into contact with a catalyst and converts it into harmless carbon dioxide. The CO oxidizer 8 does not operate when the oxidation reaction in the burner 3 is complete, and operates only when the oxidation reaction in the burner 3 is incomplete.

[0039] The condensate recovery tank 9 recovers the condensate Wb discharged from the gas-liquid separation section Sa and makes it reusable as reformed water Wa. In the condensate recovery tank 9, a water level detector Sb and a drain valve Sc are provided to adjust the water level of the stored reformed water Wa within a predetermined range. When the water level detector Sb detects the upper limit water level, the drain valve Sc is opened, while when the water level detector Sb detects the lower limit water level, the drain valve Sc is closed. In this way, the condensate recovery tank 9 is ensured to have the required amount of reformed water Wa. In addition, in order to prevent the anode off-gas Gd from leaking to the outside during the drainage operation of the reformed water Wa, the drainage position by the drain valve Sc is set near the bottom of the condensate recovery tank 9.

[0040] Also, as shown by the dashed line frame in FIG. 1, each cell stack 1, reformer 2, burner 3, each manifold Ma to Md, heat radiation cylinder Za, combustion gas pipe Zb, and cooling pipe Zc are arranged in the first region R1. The first region R1 is maintained at a temperature exceeding 600°C during the power generation operation of the power generation unit 100 and independently maintains the heat balance of heat absorption and heat generation. On the other hand, the evaporator 4, air preheater 5, anode off-gas cooler 6, and CO oxidizer 8 are arranged in the second region R2. The second region R2 is maintained at a temperature lower than that of the first region R1 and higher than room temperature during the power generation operation of the power generation unit 100. The first region R1 and the second region R2 are each surrounded by a heat insulation box, and the power generation module 20 is formed by integrating the two heat insulation boxes. The anode off-gas condenser 7, condenser fan 7a, condensate recovery tank 9, each blower 10, 11, 13, 14, 15, water pump 12, power conditioner 16, and unit controller 17 are arranged outside the power generation module 20 (room temperature region). In addition, the above-mentioned bellows expansion pipe joints B1 to B4 are used to absorb the expansion and contraction of the pipes caused by the temperature change between the cold state and the operation state.

[0041] FIG. 2 is a schematic diagram showing the configuration of the power conditioner 16 according to the present embodiment, and shows the internal configuration of the power conditioner 16 and the connection state to peripheral devices. The power generation module 20 is configured to include elements such as the cell stack 1 as described above. Further, the auxiliary machine 30 for operating the power generation module 20 includes components such as the raw fuel blowers 10 and 13, the air blowers 11, 14, and 15, the water pump 12, and the fan 7a of the anode off-gas condenser 7.

[0042] The power conditioner 16 converts the generated power of the power generation module 20 into output power corresponding to the AC power of the commercial power supply system 500. The power conditioner 16 includes DC / DC converters 16a and 16b, a smoothing capacitor 16c, a grid-connected inverter 16d, switches 16e and 16f, and control circuits 16g and 16h.

[0043] The DC / DC converter 16a boosts and converts the DC power from the power generation module 20 (boosting circuit). The smoothing capacitor 16c smoothes the output power of the DC / DC converter 16a. The grid-connected inverter 16d converts the output power of the DC / DC converter 16a into AC power equivalent to the commercial power supply system.

[0044] The output side of the grid-connected inverter 16d is electrically connected to, for example, a distribution board 610 for receiving commercial power installed in a building. The grid-connected inverter 16d and the distribution board 610 can be switched between a parallel state and a disconnected state via the switch 16e. The commercial power supply system 500 and the power demand facility 600 are electrically connected to the distribution board 610. The power demand facility 600 includes a plurality of sub-distribution boards, and load devices such as lighting fixtures, power devices, or outlets used in the building are electrically connected to each sub-distribution board.

[0045] Further, the grid-connected inverter 16d is electrically connected to the independent outlet 300. The grid-connected inverter 16d and the independent outlet 300 can be switched between a connected state and a disconnected state via the switch 16f. The independent outlet 300 is composed of a plurality of outlets into which the power plugs of various electric power-consuming devices can be inserted.

[0046] The DC / DC converter 16b and the control circuit 16g function as a driving power supply unit that supplies driving power to the auxiliary machine 30. The DC / DC converter 16b adjusts the DC voltage boosted by the DC / DC converter 16a to a DC voltage suitable for driving the auxiliary machine 30. The control circuit 16g supplies the DC voltage adjusted by the DC / DC converter 16b to the auxiliary machines 30 and drives the auxiliary machine 30 appropriately. Note that the above-mentioned auxiliary machine 30 is driven using commercial power during the startup operation and shutdown operation of the power generation unit 100, and is driven using the generated power during the power generation operation of the power generation unit 100.

[0047] The DC / DC converter 16a and the control circuit 16h function as an operating power supply unit that supplies operating power to the first load module 40 and the second load module 50. The first load module 40 is configured to include an electric heater 41 and a radiator fan 42. Similarly, the second load module 50 is configured to include an electric heater 51 and a radiator fan 52. In the independent operation mode of the power generation unit 100, each load module 40, 50 causes the electric heaters 41, 52 to generate heat to consume the excess generated power of the cell stack 1, and the radiator fans 42, 52 send airflows to the electric heaters 41, 51 respectively to promote heat dissipation.

[0048] In addition to the load modules 40, 50, an auxiliary resistor (not shown) is connected to the control circuit 16h. This auxiliary resistor is equipped to consume the excess generated power of the cell stack 1 in the independent operation mode of the power generation unit 100, and functions as a buffer when, for example, the operating power of the auxiliary machine 30 fluctuates.

[0049] The unit controller 17 controls the operation of the power generation unit 100 according to a control program created and stored in advance. The unit controller 17 is constituted by a programmable logic controller (PLC). The PLC has an arithmetic unit, a storage unit, an input unit, an output unit, and a power supply unit, and executes required arithmetic operations and sequence control using a processing program created and stored in advance. A communication unit 17a for communicating with the outside of the power generation unit 100 is provided in the unit controller 17.

[0050] <Overview of the operation of the power generation unit> Next, an overview of the operation of the power generation unit 100 will be described with reference to FIG. 1. The raw fuel gas Ga supplied into the mixed gas line Lb from the fuel inlet E2 is sent to the subsequent stage by the action of the first raw fuel blower 10. In parallel with the supply of the raw fuel gas Ga, the reformed water Wa supplied into the reformed water line Li from the condensate recovery tank 9 has its water volume adjusted by the water pump 12 and flows into the mixed gas line Lb.

[0051] The reformed water Wa flows into the evaporator 4 together with the raw fuel gas Ga in the mixed gas line Lb, and is heated by heat exchange in the evaporator 4 to become water vapor (superheated steam). The water vapor is mixed with the heated raw fuel gas Ga and flows into the reformer 2 as the mixed gas Gb.

[0052] The reformer 2 reforms the raw fuel gas Ga using the water vapor in the mixed gas Gb, generates a reformed gas Gc, and sends it to the subsequent stage. The reformed gas Gc sent out from the reformer 2 is distributed to the anodes of the respective cell stacks 1 through the anode fuel line Lc.

[0053] On the one hand, in parallel with the supply of the above-described raw fuel gas Ga, air Aa is supplied from the air inlet E3 into the cathode air line Le. The air Aa in the cathode air line Le is sent to the downstream side by the action of the first air blower 11. This air Aa is heated by heat exchange in the anode off-gas cooler 6 and further heated by heat exchange in the air preheater 5, and then distributed to the cathodes of the respective cell stacks 1. Note that, for temperature adjustment of the air Aa, etc., a part of the air Aa, i.e., air Aa1, can also be made to flow into the cathodes of the respective cell stacks 1 via the bypass path Le2.

[0054] Furthermore, in synchronization with the supply of the air Aa to the cathode, air Ab is supplied into the burner cooling air line Lh. The air Ab in the burner cooling air line Lh is sent to the burner 3 by the action of the first air blower 11. This air Ab acts as a coolant for reducing the combustion temperature of the burner 3.

[0055] Each cell stack 1 generates electricity using the reformed gas Gc that has flowed into the anode and the air Aa that has flowed into the cathode. When current sweeping is performed by the power conditioner 16 in a state where the reformed gas Gc and the air Aa are supplied to the cell stack 1, power generation (electrochemical reaction between the reformed gas and oxygen) of the cell stack 1 is started. During the power generation operation of the cell stack 1, the anode off-gas Gd is discharged from the anode to the anode off-gas line Ld, and the cathode off-gas Ge is discharged from the cathode to the cathode off-gas line Lf. The anode off-gas Gd contains the reformed gas that was unreacted at the anode, and the cathode off-gas Ge contains the oxygen that was unreacted at the cathode.

[0056] The anode off-gas Gd discharged from each cell stack 1 to the anode off-gas line Ld is collected in the first collection manifold Mc, then cooled by heat exchange in the anode off-gas cooler 6, and flows into the anode off-gas condenser 7. In the anode off-gas condenser 7, the anode off-gas Gd is cooled to below the dew point temperature, and the water vapor contained in the anode off-gas Gd condenses.

[0057] The anode off-gas Gd that has passed through the anode off-gas condenser 7 is sent to the gas-liquid separation section Sa for gas-liquid separation, and the condensed water Wb is recovered in the condensed water recovery tank 9. The condensed water Wb recovered in the condensed water recovery tank 9 is reused as the reformed water Wa as described above. Recovering the water generated by the electrochemical reaction of the reformed gas Gc and oxygen and repeatedly using it in the steam reforming reaction is called water self-sufficiency. Note that the non-condensed portion of the anode off-gas Gd (the anode off-gas Gd after gas-liquid separation) is sent to the burner 3.

[0058] The cathode off-gas Ge discharged from each cell stack 1 to the cathode off-gas line Lf is collected in the second collection manifold Md, and then mixed with the air Ab flowing in through the burner cooling air line Lh in the pipeline Lf1 and sent to the burner 3. In addition, to the burner 3, according to the operating state of the power generation unit 100, the raw fuel gas Gf supplied from the fuel inlet E1 is sent through the raw fuel line La, and the air Ac supplied from the air inlet E4 is sent through the starting air line Lj.

[0059] The burner 3 has the first burner gas Gx which is the raw fuel gas Gf and / or the anode off-gas Gd, and the second burner gas Gy which is the air Ac and / or the cathode off-gas Ge flowing in, and burns these to generate heat. That is, the first burner gas Gx is a mixed gas of the raw fuel gas Gf and the anode off-gas Gd, or in a state of either the raw fuel gas Gf or the anode off-gas Gd, and which state it is in can change depending on the operating state of the power generation unit 100 and the like. Also, the second burner gas Gy is a mixed gas of the air Ac and the cathode off-gas Ge, or in a state of either the air Ac or the cathode off-gas Ge, and which state it is in can change depending on the operating state of the power generation unit and the like. That is, according to the startup operation, power generation operation (full load operation or partial load operation), shutdown operation, etc. of the power generation unit 100, the supply gas to the burner 3 changes its state as appropriate.

[0060] Note that the raw fuel gas Gf is a type of hydrocarbon-containing gas. On the other hand, the air Ac is a type of oxidant-containing gas. During the combustion operation of the burner 3, air Ab is continuously supplied from the burner cooling air line Lh to adjust the combustion temperature.

[0061] The combustion gas Gg generated by the combustion in the burner 3 is sent to the combustion gas line Lg and passes through the heat radiation cylinder Za, the combustion gas pipe Zb, the air preheater 5, the CO oxidizer 8, and the evaporator 4 in sequence, and is discharged from the gas outlet E6 to the outside of the power generation module 20. The heat radiation cylinder Za and the combustion gas pipe Zb are arranged so that the reformer 2 can be effectively heated using the combustion gas Gg. Also, the combustion gas Gg in the combustion gas line Lg is used for heat exchange when passing through the air preheater 5 and the evaporator 4, and when carbon monoxide is contained, the carbon monoxide is converted to carbon dioxide when passing through the CO oxidizer 8.

[0062] Also, the cooling air Ad supplied from the air inlet E5 to the cooling air line Lk serves to cool the inside of the power generation module 20 when passing through the cooling pipe Zc. As will be described later, the cooling pipe Zc is installed near the cell stack 1, and the cell stack 1 can be effectively cooled by the cooling air Ad. And the cooling air Ad finally passes through the collecting pipe Lk1 and is discharged from the gas outlet E6 to the outside of the power generation module 20 together with the combustion gas Gg.

[0063] Also, in the power generation unit 100, the amount of heat (temperature) inside the power generation module 20 is controlled by adjusting the flow rate of the cooling air Ad introduced into the cooling pipe Zc. As an example, when the discharge temperature of the cathode off-gas Ge flowing out from the cell stack 1 exceeds the upper limit temperature, the unit controller 17 drives the third air blower 15, and controls the rotation speed of the third air blower 15 so that the discharge temperature of the cathode off-gas Ge becomes the target temperature (a temperature lower than the upper limit temperature by a predetermined temperature). The greater the rotation speed of the third air blower 15, the greater the flow rate of the cooling air Ad introduced into the cooling pipe Zc. Also, when the rotation speed below the lower limit value continues for a predetermined time, the unit controller 17 stops the third air blower 15.

[0064] Note that the cooling pipe Zc installed near the cell stack 1 can also be used to heat up the cell stack 1 during the startup operation of the power generation unit 100. Specifically, in the startup operation of the power generation unit 100, first, the second raw fuel blower 13 and the second air blower 14 are driven to burn the burner 3. The combustion gas Gg generated by this combustion flows through the heat radiation cylinder Za and the combustion gas pipe Zb, and heats up the cold reformer 2 from the outside by radiative heat transfer to raise its temperature. Further, the combustion gas Gg becomes the heat source of the evaporator 4 and generates water vapor from the reforming water Wa. This water vapor flows through the cold reformer 2 and the cell stack 1 in sequence, and heats up these devices from the inside by heat conduction to raise their temperatures. If there is waste heat in the combustion gas Gg discharged from the evaporator 4, the combustion gas Gg is made to flow from the pipeline Lg1 to the collecting pipe Lk1. As a result, the combustion gas Gg flows through the cooling pipe Zc, so that the cold cell stack 1 can be heated from the outside by radiative heat transfer to raise its temperature.

[0065] In the power generation operation of the power generation unit 100, "thermal self-sufficiency" means balancing the heat balance between the heat generation by the electrochemical reaction of the reformed gas Gc and oxygen in the cell stack 1, the heat generation by the combustion reaction of the anode off-gas Gd and the cathode off-gas Ge in the burner 3, and the heat absorption by the steam reforming reaction of the raw fuel gas Ga and water vapor (reforming water Wa) in the reformer 2. Also, "water self-sufficiency" means recovering the water (reforming water Wa) generated by the electrochemical reaction of the reformed gas Gc and oxygen and repeatedly using it in the steam reforming reaction.

[0066] In the power generation operation of the power generation unit 100, the output power of the grid-connected inverter 16d is equal to the value obtained by subtracting the total power losses due to the operation of the auxiliary machine 30, the power losses due to the operation of the power conditioner 16, and the power losses due to the operation of the load module 40. The load module 40 operates in the self-powered operation mode described later.

[0067] When the power generation unit 100 is operated at full load with the rated output power, the unit controller 17 sets the sweep current value for the cell stack 1 to the rated current value, and supplies the corresponding amount of the raw fuel gas Ga. When the power generation unit 100 is operated at a partial load below the rated output power and equal to or higher than the minimum output power, the unit controller 17 sets the sweep current value for the cell stack 1 to a range equal to or lower than the rated current value and equal to or higher than the lower limit current value, and supplies the corresponding amount of the raw fuel gas Ga. When the power generation unit 100 is put on standby with zero output power, the unit controller 17 sets the sweep current value for the cell stack 1 to the value corresponding to the operating power of the auxiliary machine 30, and supplies the minimum amount of the raw fuel gas Ga while keeping the power generation module 20 warm. Note that the state where the power generation unit 100 is put on standby with zero output power is referred to as "hot standby".

[0068] The power generation operation of the power generation unit 100 includes a grid-connected operation mode and an independent operation mode. In the grid-connected operation mode, as shown in FIG. 2, the switch 16e is controlled to be in the on state, and the switch 16f is controlled to be in the off state. Thereby, the power generation unit 100 is operated in parallel with the commercial power supply system 500. In the independent operation mode, conversely to FIG. 2, the switch 16e is controlled to be in the off state, and the switch 16f is controlled to be in the on state. Thereby, the power generation unit 100 is operated in a disconnected state from the commercial power supply system 500.

[0069] The unit controller 17 constantly monitors the presence or absence of a power outage in the commercial power supply system 500, and when a power outage is detected, shifts the power generation unit 100 from the grid-connected operation mode to the independent operation mode. In the independent operation mode, when an electrical device is connected to the independent outlet 300, it is possible to supply the output power of the grid-connected inverter 16d as the independent operation power to the electrical device. That is, in the disconnected state, a part of the generated power of the power generation module 20 is supplied to the electrical device via the independent outlet 300. When the commercial power supply system 500 resumes power supply from a power outage, the unit controller 17 shifts the power generation unit 100 from the independent operation mode to the grid-connected operation mode.

[0070] When the supply amount of the self-driving power exceeds the consumption amount in the self-driving mode, the power generation unit 100 causes the first load module 40 or the second load module 50 to consume the surplus of the self-driving power (that is, a part of the generated power of the power generation module 20). The adjustment of the power consumption amount of the load module 40 can be realized by adjusting the calorific value of the electric heater 41 (for example, adjusting the number of electric heaters to be energized, or adjusting the on / off duty ratio of the energization), and the same applies to the second load module 50.

[0071] <Operation as an output adjuster> As described above, the power generation unit 100 can operate at the rated output power under full load, operate at a partial load below the rated output power and above the minimum output power, or operate in hot standby with the output power being zero. That is, the power generation unit 100 can be operated as an output adjuster that operates in the range of equal to or less than the rated output power and equal to or more than the minimum output power. Note that since the power generation module 20 in the present embodiment includes an SOFC cell stack, the minimum output power in the partial load operation is set based on the minimum fuel supply amount that can maintain the thermal self-sufficiency of the power generation module 20 and the minimum fuel utilization rate that can maintain the water self-sufficiency of the power generation module 20.

[0072] The maximum output power of the power generation unit 100 in the grid-connected operation mode is equivalent to the rated output power (6 kW). Also, the minimum output power of the power generation unit 100 in the grid-connected operation mode is set to the lower limit value at which the power generation efficiency during partial load operation does not decrease with respect to the power generation efficiency during full load operation, in addition to achieving both thermal self-sufficiency and water self-sufficiency. The minimum output power in this case is, for example, equivalent to 50% (3 kW) of the rated output power (6 kW). If output adjustment below the minimum output power is required, the system will shift to hot standby.

[0073] The maximum output power of the power generation unit 100 in the self-operating mode is determined considering the aging deterioration of the cell stack 1. The maximum output power in this case is equivalent to, for example, 83% (5 kW) of the rated output power (6 kW). Also, the minimum output power of the power generation unit 100 in the self-operating mode is set as the lower limit value that allows a decrease in the power generation efficiency during partial load operation compared to that during full load operation, in addition to achieving both thermal self-sufficiency and water self-sufficiency. The minimum output power in this case is equivalent to, for example, 25% (1.5 kW) of the rated output power (6 kW). Note that when the power generation capacity of the cell stack 1 decreases due to aging deterioration, the rated output power cannot be ensured in the grid-connected operation mode. However, since the decrease in output power can be compensated by increasing the purchased power, there is no problem in system operation.

[0074] The output adjuster adjusts the output power from the power conditioner 16 by performing an operation of increasing or decreasing the output current from the grid-connected inverter 16d. The unit controller 17 increases the sweep current value for the cell stack 1 in parallel with the increase in the output current and increases the supply amount of the raw fuel gas Ga. Also, the unit controller 17 decreases the sweep current value for the cell stack 1 in parallel with the decrease in the output current and decreases the supply amount of the raw fuel gas Ga. Thereby, the power generation power of the power generation module 20 increases or decreases as the output current increases or decreases.

[0075] <Configuration of the Load Module> FIG. 3 is a perspective view showing the appearance of the power generation unit 100. As shown in FIG. 3, as a configuration on the product, the power generation unit 100 includes a unit base 60 on which the above-described power generation module 20 and auxiliary machine 30 are placed, and a box-shaped housing 62 installed on the unit base 60 so as to surround these power generation module 20 and auxiliary machine 30.

[0076] Inside the front side of the housing 62, the power conditioner 16 is arranged at the lower stage, and the unit controller 17 is arranged at the upper stage. Inside the rear side of the housing 62, the first load module 40 is arranged, and on the upper surface panel (top plate) of the housing 62, the second load module 50 is placed. Further, on the front panel of the housing 62, an outlet unit 400 having a plurality of independent outlets 300 to be described later is provided.

[0077] After shifting to the independent operation mode, the power generation unit 100 can adjust the output within the range of the minimum output power (25% output) to the maximum output power (83% output), and from the outlet unit 400, it is possible to take out the independent power generation power selected from this range as the maximum value.

[0078] The first load module 40 is standard equipment for the power generation unit 100. The first load module 40 includes an electric heater 41 having at least the power consumption corresponding to the minimum output power (25% output) of the power generation unit 100 in the independent operation mode.

[0079] The second load module 50 can be selectively added according to the power needs of the customer. The second load module 50 includes an electric heater 51 having at least the power consumption corresponding to the value obtained by subtracting the minimum output power from the maximum output power of the power generation unit 100 (58% output) in the independent operation mode.

[0080] In a specific design example, when the rated output power of the power generation unit 100 is 6 kW, the number of heaters etc. of the electric heater 41 of the first load module 40 are designed so that the maximum power consumption becomes 1.5 kW or more, and the power consumption is adjustable in the range of 0 to 1.5 kW. The number of heaters etc. of the electric heater 51 of the second load module 50 are designed so that the maximum power consumption becomes 3.5 kW or more, and the power consumption is adjustable in the range of 0 to 3.5 kW. That is, when using the two load modules 40 and 50, a design that adjusts the power consumption in the range of 0 to 5 kW is possible.

[0081] <Configuration of the self - standing socket> FIG. 4 is an enlarged view of the socket unit 400. As shown in FIG. 4, the socket unit 400 includes a panel 401, a power lamp 402, an information display unit 403, and three self - standing sockets 300a to 300c. The panel 401 has a front - exposed surface formed in a planar shape, and this surface is provided so as to be parallel to the outer surface of the front panel of the housing 62. On the surface of the panel 401, three self - standing sockets 300 are arranged closer to the right side, and near the left side thereof, a power lamp 402 and an information display unit 403 are arranged.

[0082] The self - standing socket 300 has an insertion port exposed forward, and power plugs of various power - using devices can be inserted from the front. When a power plug is inserted into this insertion port, the power - using device is connected to the self - standing socket 300. In the example shown in FIG. 4, three self - standing sockets 300a, 300b, and 300c are provided, but the number of self - standing sockets 300 is not limited to this.

[0083] The power lamp 402 lights up when power supply for self - operation is possible when a power - using device is connected to the self - standing socket 300 (when the switch 16f is in the on state), and it is possible to visually recognize whether it is in the lit state or the off state from the front. Thereby, the consumer can instantly determine whether the self - standing socket 300 is available at the present time.

[0084] The information display unit 403 displays information corresponding to the power consumption of the self - operation power in the power - using device connected to the self - standing socket 300. The information display unit 403 in the example shown in FIG. 5 is configured as a 7 - segment type display capable of displaying multiple - digit numbers, and the displayed numbers are visible from the front. Since the display of the information display unit 403 is arranged close to the insertion port of the self - standing socket 300, a consumer in front of the insertion port (especially a consumer who intends to use the self - standing socket 300) can easily visually recognize the display of the display.

[0085] The available power of the self - contained socket 300 can be set within a range that is equal to or greater than the minimum output power in the self - operating mode and equal to or less than the rated output power in the grid - connected operating mode, based on the equipment information of the first load module 40 and the second load module 50.

[0086] As described above, the first load module 40 is equipped with an electric heater 41 that consumes electric power (1.5 kW) corresponding to the minimum output power (25% output) in the self - operating mode. In the case where the second load module 50 is not selected, when there is no power - consuming device connected to the self - contained socket 300, all of the minimum output power can be consumed by the first load module 40. That is, in a state where the first load module 40 is not operating, all of the minimum output power (1.5 kW) can be taken out from the self - contained socket 300. That is, when only the first load module 40 is standard - equipped, the available power of the self - contained socket 300 can be set to correspond to the minimum output power (1.5 kW).

[0087] Also, the second load module 50 is equipped with an electric heater 51 that consumes electric power (3.5 kW) corresponding to 58% of the maximum output power in the self - operating mode. In the case where the second load module 50 is selected, when there is no power - consuming device connected to the self - contained socket 300, all of the maximum output power can be consumed by the first load module 40 and the second load module 50. That is, in a state where the two load modules 40 and 50 are not operating, all of the maximum output power (5 kW) can be taken out from the self - contained socket 300. That is, when the second load module 50 is additionally equipped, the available power of the self - contained socket 300 can be set to correspond to the maximum output power (5 kW).

[0088] <Output adjustment of the self - contained socket> While the power generation unit 100 is operating in the self-sustaining operation mode, the unit controller 17 adjusts the power consumption of the load modules 40 and 50 so that the effective output power Qe of the self-sustaining outlet 300, which is obtained by subtracting the first power loss Q1 caused by the operation of the load modules 40 and 50 from the generated power Qg of the power generation module 20, follows the power consumption Qc of the electrical equipment. This relationship is expressed by Equation (1). Since the power consumption Qc of the electrical equipment is a variable value, this relational expression means that if the generated power Qg of the power generation module 20 is a constant value, the first power loss Q1 of the load modules 40 and 50, that is, the power consumption of the electric heaters 41 and 51, is increased or decreased. Qc = Qe = Qg - Q1 …(1)

[0089] As described above, the adjustment of the power consumption of the load modules 40 and 50 is executed by increasing or decreasing the number of electric heaters 41 and 51 to be energized or adjusting the duty ratio of on / off of the energization of the electric heaters 41 and 51.

[0090] Also, while the power generation unit 100 is operating in the self-sustaining operation mode, the unit controller 17 operates the power generation module 40 so that the generated power Qg obtained by adding the second power loss Q2 caused by the operation of the auxiliary machine 30 and the third power loss Q3 caused by the operation of the power conditioner 16 to the set value Qs of the available power of the self-sustaining outlet 300 is obtained. This relationship is expressed by Equation (2). If the second power loss Q2 and the third power loss Q3 are substantially constant values, this relational expression means that if the set value Qs of the available power is given, the generated power Qg of the power generation module 20 is determined as a constant value. Qg = Qs + Q2 + Q3 …(2)

[0091] The second power loss Q2 includes the power consumption of the raw fuel blowers 10 and 13, the air blowers 11, 14, and 15, the water pump 12, and the condenser fan 7a, as well as the power consumption of the heat dissipation fans 42 and 52 and the auxiliary resistors. That is, the first power loss Q1 includes only the power consumption of the electric heaters 41 and 51. In the self-sustaining operation mode, the second power loss Q2 is maintained at a substantially constant value by the operation of the auxiliary resistors.

[0092] Since the available power Qs is equal to the maximum power consumption of the load modules 40 and 50 (the maximum value of the first power loss Q1), Equation (3) can be obtained from Equations (1) and (2). That is, assuming that the generated power Qg, the second power loss Q2, and the third power loss Q3 are approximately constant values, it shows that the effective output power Qe of the self - contained outlet 300 can be made to match the power consumption Qc of the electrical equipment by increasing or decreasing the first power loss Q1 caused by the operation of the electric heaters 41 and 51. Qc = Qe = Qg - Q1 - Q2 - Q3 …(3)

[0093] 〔Second Embodiment〕 FIG. 6 is a schematic diagram showing the configuration of the power generation unit according to the second embodiment. As shown in FIG. 5, the power generation unit 100 is of a cogeneration type using a fuel cell, and a heat recovery unit 200 described later is provided together.

[0094] In this embodiment, the auxiliary equipment 30 for operating the power generation module 20 includes the raw fuel blowers 10 and 13, the air blowers 11, 14, and 15, the water pump 12, and in addition, the fan 63a of the radiator 63 and the circulation pump 64 described later. Since the anode off - gas condenser 7 has been changed to a water - cooled type, the aforementioned fan 7a is not included.

[0095] <Configuration of Heat Recovery Unit> FIG. 6 is a schematic diagram showing the configuration of the heat recovery unit according to this embodiment. As shown in FIG. 6, some of the equipment of the power generation unit 100 forms the heat recovery unit 200 together with the hot water storage tank 65. The heat recovery unit 200 is a unit that recovers heat from at least one of the anode off - gas Gd and the combustion gas Gg and makes the recovered heat available for heating the hot water stored in the hot water storage tank 65.

[0096] The heat recovery unit 200 mainly consists of an anode off-gas condenser 7, a heat recovery device 61, a heater 62, a radiator 63, a circulation pump 64, a hot water storage tank 65, and a cooling water line Lm. The cooling water line Lm is a path for circulating the cooling water Wc so that it passes through the heat recovery device 61, the anode off-gas condenser 7, the heater 62, the circulation pump 64, the radiator 63 in sequence and returns to the heat recovery device 61. The hot water storage tank 65 of this embodiment is a sealed hot water storage tank used in a heat pump water heater or the like.

[0097] The heater 62 is a heat exchange coil arranged in the hot water storage tank 65, and heats the hot water in the hot water storage tank 65 by the heat of the cooling water Wc. The circulation pump 64 is a device for circulating the cooling water Wc in the cooling water line Lm, and its rotation speed is variable. By changing the rotation speed of the circulation pump 64, the circulation flow rate of the cooling water Wc can be adjusted. The radiator 63 is configured to be able to efficiently dissipate the heat of the cooling water Wc using the fan 63a.

[0098] The operation of the heat recovery unit 200 is controlled by the unit controller 17. Specifically, the rotation speed of the circulation pump 64 is controlled so that the return temperature of the cooling water Wc (the temperature near the outlet of the anode off-gas condenser 7) becomes a predetermined target temperature Ts. If the return temperature exceeds the target temperature Ts even when the rotation speed of the circulation pump 64 is adjusted to the upper limit, in order to ensure the cooling amount of the anode off-gas Gd in the anode off-gas condenser 7, the fan 63a of the radiator 63 is driven, and heat dissipation from the cooling water Wc is promoted. The fan 63a of the radiator 63 is driven when there is no consumption of hot water at the demand side and the heat storage amount (heat recovery amount) of the hot water storage tank 65 is maximized.

[0099] In this embodiment, as an example, the target temperature Ts is set so that the hot water in the hot water storage tank 65 is approximately 75°C. However, the actual temperature of the hot water in the hot water storage tank 65 may vary depending on the demand for the hot water at that time and other factors. For example, immediately after the water supply Wd is supplied to the hot water storage tank 65 that has run out of hot water, the temperature of the hot water in the hot water storage tank 65 may be significantly lower than 75°C. Also, when the condensed water Wb in the condensate recovery tank 9 falls below the lower water level while the rotational speed of the circulation pump 64 is below the upper limit, the fan 63a of the radiator 63 is driven to restore the water storage volume.

[0100] The specific configuration of the heat recovery unit 200 is not limited to that shown in FIG. 6 and can be changed according to various circumstances. For example, in the example of FIG. 6, the anode off-gas condenser 7 is arranged on the downstream side of the heat recovery device 61, but the heat recovery device 61 may be arranged on the downstream side of the anode off-gas condenser 7. Also, when the temperature of the combustion gas Gg after heat is utilized by the evaporator 4 or the like is low, the installation of the heat recovery device 61 may be omitted. Further, the installation of the heater 62 may be omitted, and instead of the cooling water line Lm, a path for circulating the hot water in the hot water storage tank 65 (a path for circulating the hot water so that it passes through the hot water storage tank 65, the circulation pump 64, the radiator 63, the heat recovery device 61, and the anode off-gas condenser 7 in sequence and returns to the hot water storage tank 65) may be provided. In this case, it is preferable that the hot water returning to the hot water storage tank 65 returns to the top of the hot water storage tank 65.

[0101] In addition to the hot water storage tank 65, the heat recovery unit 200 includes a water heater 66, a temperature control valve 67, and a water supply line Ln, and serves to supply hot water at a required temperature (the temperature of the hot water required by the demand destination or the range of that temperature) to the demand destination. In this embodiment, as an example, this required temperature is in the range of 50 to 60°C.

[0102] The water heater 66 is arranged on the downstream side of the hot water storage tank 65 and sends out the hot water supplied from the hot water storage tank 55 toward the demand destination, and is capable of performing a heating operation to heat the hot water. In this embodiment, as the water heater 66, a gas water heater that burns city gas, propane gas, or the like to perform the heating operation is adopted.

[0103] The temperature control valve 67 is arranged on the downstream side of the water heater 66 and is capable of performing a mixing operation of mixing the feed water Wd into the hot water delivered from the water heater 66 to lower the temperature. The water supply line Ln is a line that supplies the feed water Wd to the hot water storage tank 65 and the temperature control valve 67. The hot water storage tank 65 is supplied with the amount of feed water Wd corresponding to the hot water consumed at the demand side, and the temperature control valve 67 is supplied with the feed water Wd for use in the mixing operation. As the feed water Wd, tap water, well water, soft water treated by a water softening device, or the like is used.

[0104] <Output adjustment of the self - contained socket> In the above formulas (1) to (3), it was explained assuming that the second power loss Q2 can be regarded as a substantially constant value due to the operation of the auxiliary resistor. However, when the auxiliary resistor is not provided, the second power loss Q2 can vary greatly depending on the rotational speed of the radiator fan 63a and the rotational speed of the circulation pump 64. In that case, it is desirable to adjust the power generation power Qg of the power generation module 20 in consideration of the actual value of the second power loss Q2. By adjusting the power generation power Qg according to the second power loss Q2, the effective output power Qe can be surely made to match the power consumption Qc, so that the output voltage of the self - contained socket 300 is stabilized.

[0105] For example, when the raw fuel blowers 10, 13, the air blowers 11, 14, 15, the water pump 12, the condenser fan 7a, the heat dissipation fans 42, 52, the radiator fan 63a, and the circulation pump 64 are driven by DC motors, these fluid machines control the rotational speed by changing the drive voltage (average voltage) by pulse width modulation (PWM) and increase or decrease the flow rate. Therefore, a table of the duty ratio and the shaft power (power consumption) of the DC motor is created in advance, and the power consumption of each fluid machine is calculated from the current duty ratio. Then, by adding the numerical values of each power consumption, it becomes possible to accurately obtain the second power loss Q2.

[0106] When the power consumption of the cooling fans 42 and 52 of the load modules 40 and 50 is relatively large, the power consumption of the cooling fans 42 and 52 may be excluded from the first power loss Q1 and included in the second power loss Q2. According to this measure, it becomes possible to stably follow the effective output power Qe with respect to the change in the power consumption Qc.

[0107] 〔Other Modification Examples〕

[0108] Each of the first load module 40 and the second load module 50 may be configured to consume the surplus power with an electric resistance circuit or a switching element instead of consuming it with the electric heater 41.

[0109] The cell stack 1 constituting the power generation module 20 may be a molten carbonate fuel cell (MCFC) instead of a solid oxide fuel cell (SOFC). The MCFC is a high-temperature operating fuel cell like the SOFC and has high power generation efficiency.

[0110] The power generation module 20 using a fuel cell is not limited to the type that generates power with a single-stage cell stack 1, and may be of the type that generates power with a two-stage or more cell stack 1. Specifically, water vapor is removed from the anode off-gas discharged from the previous-stage cell stack to generate a reformed gas, and this reformed gas is supplied to the anode of the next-stage cell stack. In addition, when generating the reformed gas, carbon dioxide contained in the anode off-gas may be removed using a separation membrane, an absorbent, or the like. By configuring to generate power with a two-stage or more cell stack, the fuel utilization rate can be significantly increased.

[0111] The power generation module 20 using a fuel cell is not limited to a configuration that supplies reformed gas to the cell stack, and may be configured to supply pure hydrogen gas. Specifically, hydrogen gas supplied from an external hydrogen production site through a transportation infrastructure is introduced into the anode of the cell stack. When hydrogen gas is used as the primary fuel, components required for steam reforming and water self-sufficiency (such as reformer 2, evaporator 4, anode off-gas condenser 7, gas-liquid separation section Sa, condensate recovery tank 9, water pump 12, etc.) can be omitted.

[0112] The power generation unit 100 is not limited to a type using a fuel cell, and can be changed to other types. The power generation unit may be of a type using a solar cell, or may be of a type that rotates a generator using an organic Rankine cycle, a steam turbine, a gas turbine, or a gas engine.

[0113] According to the power generation unit assembly 2000 of the present embodiment described above, the following effects can be obtained.

[0114] (1) The power generation unit 100 operated in a parallel state or a disconnected state with respect to the commercial power supply system 500 includes a power generation module 20 operated by an auxiliary machine 30, a power conditioner 16 that converts the generated power of the power generation module 20 into output power corresponding to the AC power of the commercial power supply system 500, a unit controller 17 that controls the power generation module 20 and the auxiliary machine 30, a self-sufficient outlet 300 that supplies a part of the generated power of the power generation module 20 to power-consuming devices in the disconnected state, and a first load module 40 that internally consumes a part of the generated power of the power generation module 20 in the disconnected state. The unit controller 17 and the power conditioner 16 are configured to operate in a grid-connected operation mode in the parallel state and in a self-sufficient operation mode in the disconnected state, and it is optional to further include a second load module 50 that internally consumes a part of the generated power of the power generation module 20 in the disconnected state according to the power needs of the consumer.

[0115] The power generation unit 100 is always equipped with a self - contained outlet 300 and a first load module 40 to meet the minimum power needs in the event of a power outage in the commercial power supply system 500. However, for the demand to urgently connect more power - using devices to the self - contained outlet 300, the installation of the second load module 50 can be selected. Since the second load module 50 is selected by the customer as an optional device, for customers who do not require additional installation, the introduction cost of the power generation unit 100 can be suppressed.

[0116] Also, in the case of introducing multiple power generation units 100, it is also possible to equip only some of the power generation units 100 with the second load module 50. Therefore, according to the deployment situation of emergency power - using devices, the self - contained outlets 300 can be distributed and installed, and the available power for each self - contained outlet 300 can also be changed, realizing a flexible operation mode.

[0117] (2) In the power generation unit 100 of (1), the available power Qs of the self - contained outlet 300 is configured to be settable within a range not less than the minimum output power in the self - operation mode and not more than the rated output power in the grid - connected operation mode, based on the equipment information of the first load module 40 and the second load module 50.

[0118] In the case where the power needs of the customer during a power outage are not much, it is possible to set the available power Qs equivalent to the minimum output power by using only the first load module 40 (maximum power consumption: 1.5 kW). Conversely, in the case where the power needs of the customer during a power outage are considerable, by using the second load module 50 (maximum power consumption: 1.5 - 4.5 kW) in combination, it is possible to set the available power Qs equivalent to 50% of the rated output power at the minimum and 100% of the rated output power at the maximum. When no power - using devices are connected to the self - contained outlet 300, the power loss due to the operation of the load modules 40 and 50 becomes extremely large. However, by suppressing the setting of the available power Qs according to the equipment status of the load modules 40 and 50, the reduction of power loss can be realized.

[0119] (3) In the power generation unit 100 of (2), the power generation module 20 includes a cell stack 1 integrating solid oxide fuel cells, and the minimum output power is set based on the minimum fuel supply amount capable of maintaining the thermal self-sufficiency of the power generation module 20 and the minimum fuel utilization rate capable of maintaining the water self-sufficiency of the power generation module 20.

[0120] When operating in the self-sustaining operation mode, the power generation unit 100 operates at a power equal to or higher than the minimum output power. In this operating state, since the thermal self-sufficiency and water self-sufficiency of the power generation module 20 are maintained simultaneously, power supply can be continued from the self-sustaining outlet 300 until the commercial power supply system 500 resumes power after a power outage. Also, after resuming power from a power outage, it is possible to quickly shift to the grid-connected operation mode.

[0121] (4) In the power generation unit 100 of (1) to (3), each of the first load module 40 and the second load module 50 includes one selected from an electric heater 41, an electric resistance circuit, and a switching element.

[0122] Load devices such as electric heaters 41 and 51 convert electrical energy into thermal energy to consume surplus power. Since these load devices can easily control the calorific value with a relatively simple control circuit, they are suitable for the applications of the load modules 40 and 50 that are exclusively used during a power outage of the commercial power supply system 500.

[0123] As described above, the embodiments of the present invention have been explained. However, the configuration of the present invention is not limited to the above embodiments, and various modifications can be made without departing from the gist of the invention. That is, the above embodiments should be considered as illustrative in all respects and not restrictive. The technical scope of the present invention is shown not by the description of the above embodiments but by the claims, and it should be understood that all modifications belonging to the meaning and scope equivalent to the claims are included.

[0124] 〔Contribution to the Sustainable Development Goals (SDGs) Led by the United Nations〕 The power generation unit and power supply system according to the present disclosure reduce carbon dioxide emissions by improving the primary energy efficiency and can contribute to the achievement of Goal 13, "Take urgent action to combat climate change", of the SDGs (Sustainable Development Goals). In addition, the power generation unit and power supply system according to the present disclosure can independently maintain power supply in the event of a power outage due to a natural disaster and can contribute to the achievement of Goal 11, "Sustainable cities and communities", of the SDGs.

Explanation of Signs

[0125] 1 Cell stack 2 Reformer 3 Burner 4 Evaporator 5 Air preheater 6 Anode off-gas cooler 7 Anode off-gas condenser 7a Fan 8 CO oxidizer (carbon monoxide oxidizer) 9 Condensate recovery tank 10 First primary fuel blower 11 First air blower 12 Water pump 13 Second primary fuel blower 14 Second air blower 15 Third air blower 16 Power conditioner 16a, 16b DC / DC converter 16c Smoothing capacitor 16d Grid connection inverter 16e, 16f Switch 16g, 16h Control circuit 17 Unit controller 17a Communication unit 20 Power generation module 30 Auxiliary equipment 40 First load module 41 Electric heater 42 Radiator fan 50 Second load module 51 Electric heater 52 Heat dissipation fan 61 Heat recovery unit 62 Heater 63 Heat sink 63a Fan 64 Circulation Pump 65 Heat medium tank (hot water tank) 66 Combustion-type water heater (gas water heater) 67 Temperature control valve 100 generating units 200 Heat Recovery Unit 300 Freestanding outlet 300a, 300b, 300c independent outlet 400 outlet unit 401 Panel 402 Power lamp 403 Information display section 500 Commercial power system 600 Demand equipment 610 Switchboard Aa, Ab, Ac Air Ad Cooling air B1 First bellows type expansion joint B2 Second bellows type expansion joint B3 Third bellows type expansion joint B4 No. 4 Bellows Expansion Joint E1,E2 fuel intake E3, E4, E5 air intakes E6 Gas outlet Ga, Gf raw fuel gas Gb mixed gas Gc reformed gas Gd anode off-gas Ge cathode offgas Gg Combustion gas La raw fuel line Lb mixed gas line Lc anode fuel line Ld Anode off-gas line Le cathode air line Lf Cathode off-gas line Lg combustion gas line Lh Air line for burner cooling Li Reformed water line Lj Starting air line Lk Air line for cooling Lk1 Collector pipe Lm Cooling water line Ln Feed water line Lw Condensate recovery line Ma First distribution manifold Mb Second distribution manifold Mc First collection manifold Md Second collection manifold R1 First region R2 Second region Sa Gas-liquid separator Sb Water level detector Sc Drain valve Wa Reformed water Wb Condensate Za Heat radiation cylinder Zb Combustion gas pipe Zc Cooling pipe

Claims

1. A power generation unit that operates in a parallel state or a disconnected state with respect to a commercial power supply system, a power generation module operated by auxiliary equipment, a power conditioner that converts the generated power of the power generation module into output power corresponding to the AC power of the commercial power supply system, a controller that controls the power generation module and the auxiliary equipment, a self - contained outlet that supplies a part of the generated power of the power generation module to electrical equipment during the disconnected state, and a first load module that internally consumes a part of the generated power of the power generation module during the disconnected state, and comprises: the controller and the power conditioner are configured to operate in a grid - connected operation mode in the parallel state and in a self - contained operation mode in the disconnected state, optionally, a second load module that internally consumes a part of the generated power of the power generation module during the disconnected state according to the power needs of the customer is further provided Power generation unit.

2. The power that can be supplied from the self - contained outlet is configured to be set within a range that is not less than the minimum output power in the self - contained operation mode and not more than the rated output power in the grid - connected operation mode based on the equipment information of the first load module and the second load module The power generation unit according to Claim 1.

3. The power generation module includes a cell stack integrating solid oxide fuel cells, the minimum output power is set based on the minimum fuel supply amount that can maintain the thermal self - sufficiency of the power generation module and the minimum fuel utilization rate that can maintain the water self - sufficiency of the power generation module The power generation unit according to Claim 2.

4. Each of the first load module and the second load module comprises one type selected from an electric heater, an electric resistance circuit, and a switching element The power generation unit according to any one of Claims 1 to 3.

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