JP2016192396A - Cogeneration system and operation method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cogeneration system capable of reducing total water feeding time by simultaneously performing water feeding of a hot-water storage unit, exhaust heat recovery circuit, and fuel cell unit, with simple operation without leaving air in a system.SOLUTION: A cogeneration system includes a controller 4 for performing control so as to open a water supply electromagnetic valve 9 in a fuel cell unit 101 when water feeding operation for a hot-water storage unit 102 has started, and start activation of an inner circulation pump 6 installed in an inner circulation circuit 5 in the fuel cell unit when an inner tank water amount detector 8 in the fuel cell unit has detected water's inflow into the fuel cell unit.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a cogeneration system including a fuel cell unit that generates electric power and heat by generating power, a hot water storage unit including a hot water storage tank that stores heat of the fuel cell unit, and an operating method thereof.

  In such a cogeneration system, the water filling operation is performed because the water inside the system is empty after installation or after repair work.

  When performing the water filling operation, air remains in the exhaust heat recovery circuit that circulates the water in the hot water storage tank between the fuel cell unit and the hot water storage unit and recovers the exhaust heat of the fuel cell unit to the hot water storage tank as hot water. If this is the case, an exhaust heat recovery failure occurs due to an increase in the pressure loss of the path and the abnormal temperature rise of the fuel cell is caused. Therefore, it is necessary to perform the water filling operation so that no air remains.

  The conventional cogeneration system includes an air venting means provided in the exhaust heat recovery circuit and a valve provided downstream thereof, and after filling the hot water storage unit, the air venting means is opened and exhausted with the valve closed. There has been proposed a method of reliably removing air from the exhaust heat recovery circuit by performing water filling of the heat recovery circuit (see, for example, Patent Document 1).

  In another conventional cogeneration system, when the water level in the hot water storage tank reaches above the water outlet to the exhaust heat recovery circuit provided at the bottom of the hot water storage tank, the exhaust heat provided in the exhaust heat recovery circuit. By starting the operation of the recovery pump, the exhaust heat recovery circuit will begin to fill before the hot water storage tank is full. Has been proposed (see, for example, Patent Document 2).

JP 2012-004132 A JP 2014-134355 A

  However, in the configuration of Patent Document 1, it can be visually confirmed that the air in the exhaust heat recovery circuit has escaped, but the air can be surely removed. However, since the operator visually confirms while manually operating the valve, the work is complicated. In addition, in order to complete water filling as a cogeneration system, it is necessary to perform water filling of the hot water storage unit in advance, water filling of the fuel cell unit after filling of the exhaust heat recovery circuit, and the total water filling time is long. there were.

Moreover, in the structure of patent document 2, when the water level in a hot water storage tank reaches the upper part rather than the water extraction port to the exhaust heat recovery circuit provided in the hot water storage tank bottom, the exhaust heat recovery provided in the exhaust heat recovery circuit By starting the pump operation, it is possible to prevent the exhaust heat recovery circuit from getting air in, but the water supply amount to reach the upper part of the water outlet must be set in advance. Since the setting value varies depending on the shape and configuration, the choice of hot water storage units is limited, and if the position of the water outlet is lower than the position of the exhaust heat recovery pump, it detects whether water is being passed through the exhaust heat recovery pump Since this is not possible, air may be involved in the exhaust heat recovery pump, and the fuel cell unit needs to be refilled by a separate operation, resulting in a long total water filling time.

  The present invention solves the above-described conventional problems, and regardless of the type of hot water storage unit, the hot water storage unit, the exhaust heat recovery circuit, and the fuel cell unit are filled with water without leaving air in the system with a simple operation. An object of the present invention is to provide a cogeneration system that shortens the total water filling time and an operation method thereof.

  In order to solve the above problems, a cogeneration system according to the present invention includes a fuel cell unit that generates power and heat by generating power, and a hot water storage unit that includes a hot water storage tank that stores heat of the fuel cell unit. An exhaust heat recovery circuit for supplying the water in the hot water storage tank to the fuel cell unit and recovering the exhaust heat of the fuel cell unit, and then returning it to the hot water storage tank; and inside the fuel cell unit An internal circulation circuit that circulates and cools water, an internal circulation pump that is disposed in the internal circulation circuit, an internal tank that is disposed in the internal circulation circuit and stores internally circulated water, and an amount of water in the internal tank can be detected An internal tank water amount detector, and a water supply electromagnetic valve that opens and closes to flow through and shut off a passage for supplying water from the exhaust heat recovery circuit to the internal circulation circuit; A controller, and when the controller starts water filling operation by supplying water to the hot water storage tank, the water supply electromagnetic valve is opened, and the internal tank water amount detector causes water to flow into the fuel cell unit. When this is detected, control is performed to start the operation of the internal circulation pump.

  In order to solve the above problems, a cogeneration system operation method according to the present invention includes a cogeneration system operation method that generates power and heat by performing power generation, and the fuel cell unit. A hot water storage unit having a hot water storage tank for storing heat, and exhaust heat for returning the water in the hot water storage tank after supplying the water in the hot water storage tank to the fuel cell unit to recover the exhaust heat of the fuel cell unit A recovery circuit; an internal circulation circuit that circulates and cools water inside the fuel cell unit; an internal circulation pump that is disposed in the internal circulation circuit; and an internal that is disposed in the internal circulation circuit and stores internally circulated water A tank, an internal tank water amount detector capable of detecting the amount of water in the internal tank, and supplying water from the exhaust heat recovery circuit to the internal circulation circuit An operation method of a cogeneration system including a water supply solenoid valve that opens and closes to flow through and shut off a passage, and when the water filling operation is started by supplying water to the hot water storage tank, the water supply solenoid valve is opened. And a step of starting the operation of the internal circulation pump when the internal tank water amount detector detects that water has flowed into the fuel cell unit.

  This makes it possible to reduce the total water filling time by filling the hot water storage unit, exhaust heat recovery circuit, and fuel cell unit without leaving air in the system with a simple operation regardless of the type of hot water storage unit. It becomes possible.

  According to the cogeneration system of the present invention, regardless of the type of hot water storage unit, the hot water storage unit, the exhaust heat recovery circuit, and the fuel cell unit are filled with water without leaving air in the system with a simple operation. Water filling time can be shortened.

Configuration diagram of a cogeneration system according to Embodiments 1, 2, and 3 of the present invention The flowchart explaining the water filling operation of the cogeneration system in Embodiment 1 of this invention The flowchart explaining the water filling operation of the cogeneration system in Embodiment 2 of this invention The flowchart explaining the water filling operation of the cogeneration system in Embodiment 3 of this invention Configuration diagram of cogeneration system in Embodiment 4 of the present invention Flowchart explaining the water filling operation of the cogeneration system in Embodiment 4 of the present invention

  According to a first aspect of the present invention, there is provided a fuel cell unit that generates electric power and heat by generating electric power, a hot water storage unit that includes a hot water storage tank that stores heat of the fuel cell unit, and water in the hot water storage tank is used as the fuel cell. An exhaust heat recovery circuit for supplying the unit to recover the exhaust heat of the fuel cell unit and then returning it to the hot water storage tank; and an internal circulation circuit for circulating water to cool the fuel cell unit. An internal circulation pump disposed in the internal circulation circuit, an internal tank disposed in the internal circulation circuit for storing internally circulated water, an internal tank water amount detector capable of detecting the amount of water in the internal tank, and the exhaust heat recovery A water supply solenoid valve that opens and closes to pass and shut off a passage for supplying water to the internal circulation circuit, and a controller, and the controller supplies water to the hot water storage tank. When water filling operation is started, the water supply solenoid valve is opened, and when the internal tank water amount detector detects that water has flowed into the fuel cell unit, control is performed to start operation of the internal circulation pump. It is a generation system.

  In particular, the second invention is the first invention, further comprising a water supply amount detector for detecting the amount of water supplied to the hot water storage unit, and an exhaust heat recovery pump disposed in the exhaust heat recovery circuit. The heat recovery pump is installed downstream of the hot water storage tank and upstream of the water supply electromagnetic valve, and when the controller detects completion of water filling of the hot water storage unit by the water supply amount detector, It controls to start the operation of the exhaust heat recovery pump.

  According to a third aspect of the invention, in particular, in the first aspect of the invention, the exhaust heat recovery pump is disposed in the exhaust heat recovery circuit, and the exhaust heat recovery pump is disposed downstream of the hot water storage tank and upstream of the water supply electromagnetic valve. And the controller controls to start the operation of the exhaust heat recovery pump when a first time has elapsed since the start of the water filling operation.

  In a fourth aspect of the invention, particularly in the second aspect of the invention, the controller detects completion of filling of the hot water storage unit with the water supply amount detector, and completes filling of the fuel cell unit with the internal tank water amount detector. When it detects, it controls to start the said fuel cell unit.

  In a fifth aspect of the present invention, in particular, in any one of the first to fourth aspects of the invention, after the controller operates the internal circulation pump for a second time set in advance, the fuel quantity is detected by the internal tank water amount detector. When the completion of water filling of the battery unit is not detected, the internal circulation pump is controlled to operate again.

  According to a sixth aspect of the present invention, particularly in the third aspect of the present invention, the apparatus further comprises a water supply amount detector installed in a drainage path connected to the upper part of the hot water storage tank, and the controller sets the exhaust heat recovery pump in advance. When the water supply amount detector does not detect completion of water filling of the hot water storage unit after operating for 3 hours, the hot water storage unit is controlled to perform water filling operation again.

According to a seventh aspect of the present invention, in the first aspect of the invention, the water heater according to the first aspect further includes a water supply path for supplying tap water to the bottom of the hot water storage tank, and the controller is configured to After closing the route except the water supply route, the water supply electromagnetic valve is opened, and water is passed into the internal tank by the water supply pressure of the hot water applied to the hot water storage tank.

  According to an eighth aspect of the invention, in particular, in the seventh aspect of the invention, the exhaust heat recovery pump is disposed in the exhaust heat recovery circuit, and the exhaust heat recovery pump is disposed downstream of the hot water storage tank and upstream of the water supply electromagnetic valve. And the controller controls the start of the operation of the exhaust heat recovery pump after the internal tank water amount detector detects that water has flowed into the fuel cell unit. .

  According to a ninth invention, in any one of the first to eighth inventions, a fuel processor for producing hydrogen used for power generation operation of the fuel cell unit from a raw material and reformed water by a reforming reaction, and the internal A reforming water path for supplying tank water as the reforming water to the fuel processor, and a reforming water pump disposed in the reforming water path, wherein the controller includes the internal tank. When the water amount detector detects that water has flowed into the fuel cell unit, it controls to start the operation of the reforming water pump.

  In a tenth aspect of the invention, particularly in any one of the first to ninth aspects of the invention, when the controller detects that the water filling of the internal circulation circuit has been completed, the fuel cell unit starts a start-up preparation operation. It is something to control.

  An eleventh aspect of the invention is directed to a fuel cell unit that generates electric power and heat by generating electric power, a hot water storage unit that includes a hot water storage tank that stores heat of the fuel cell unit, and water in the hot water storage tank to the fuel cell. An exhaust heat recovery circuit for supplying the unit to recover the exhaust heat of the fuel cell unit and then returning it to the hot water storage tank; and an internal circulation circuit for circulating water to cool the fuel cell unit. An internal circulation pump disposed in the internal circulation circuit, an internal tank disposed in the internal circulation circuit for storing internally circulated water, an internal tank water amount detector capable of detecting the amount of water in the internal tank, and the exhaust heat recovery An operation method of a cogeneration system comprising a water supply solenoid valve that opens and closes in order to pass and shut off a passage for supplying water to the internal circulation circuit. When the water supply operation is started by supplying water to the hot water storage tank, the step of opening the water supply electromagnetic valve and the internal circulation pump detecting the water flow into the fuel cell unit when the internal tank water amount detector detects that water has flowed into the fuel cell unit. A method of operating the cogeneration system, comprising the step of starting the operation of

  According to a twelfth aspect of the present invention, there is provided a fuel cell unit that generates electric power and heat by generating power, a hot water storage unit that includes a hot water storage tank that stores the heat of the fuel cell unit, and water in the hot water storage tank. An exhaust heat recovery circuit for supplying the unit to recover the exhaust heat of the fuel cell unit and then returning it to the hot water storage tank; and an internal circulation circuit for circulating water to cool the fuel cell unit. An internal circulation pump disposed in the internal circulation circuit, an internal tank disposed in the internal circulation circuit for storing internally circulated water, an internal tank water amount detector capable of detecting the amount of water in the internal tank, and the exhaust heat recovery A water supply solenoid valve that opens and closes in order to flow through and shut off a passage that supplies circuit water to the internal circulation circuit, and a water supply path that supplies tap water to the bottom of the hot water storage tank. A method for operating the cogeneration system, wherein when a hot water filling operation is started by supplying water to the hot water storage tank, paths other than the exhaust heat recovery circuit and the water supply path are closed out of the paths communicating with the hot water storage tank. Then, the step of opening the water supply solenoid valve and passing water into the internal tank by the water supply pressure applied to the hot water storage tank, and the internal tank water amount detector causes water to flow into the fuel cell unit. When this is detected, the operation method of the cogeneration system has a step of starting the operation of the internal circulation pump.

Embodiments of the present invention will be described below with reference to the drawings. In all the drawings, the same or corresponding parts are denoted by the same reference numerals, and redundant description is omitted. Further, in all the drawings, only components necessary for explaining the present invention are extracted and illustrated, and other components are not illustrated. Furthermore, the present invention is not limited to the following embodiment.

(Embodiment 1)
FIG. 1 is a configuration diagram of a cogeneration system according to Embodiment 1 of the present invention.

  As shown in FIG. 1, the cogeneration system according to Embodiment 1 of the present invention includes a fuel cell including an internal circulation circuit 5, an internal circulation pump 6, an internal tank 7, an internal tank water amount detector 8, and a water supply electromagnetic valve 9. The unit 101 includes a hot water storage unit 102 including a hot water storage tank 1, a water supply path 11, a drainage path 12, and a water supply amount detector 13, an exhaust heat recovery circuit 2, an exhaust heat recovery pump 3, and a controller 4.

  The internal circulation circuit 5 is a circuit through which cooling water for cooling a fuel cell (not shown) installed in the fuel cell unit 101 circulates, and the internal circulation circuit 5 via a heat exchanger (not shown). The exhaust heat recovery circuit 2 is configured to recover the exhaust heat. When the fuel cell unit 101 includes a reformer that generates hydrogen from the raw material gas, the fuel cell unit 101 also includes a circuit that circulates water used for reforming.

  The internal circulation pump 6 is installed in the internal circulation circuit 5 and circulates the water in the internal circulation circuit 5, and its output is changed by the controller 4 in the circulation control. The internal tank 7 is installed in the internal circulation circuit 5 in the fuel cell unit 101, and is a tank for temporarily storing water used for the circulation of the internal circulation circuit 5 or for condensing water generated by exhaust heat recovery. In order for the fuel cell unit 101 to continue operation, water is required in the internal tank 7.

  The internal tank water amount detector 8 is a detector that detects that water remains in the internal tank 7, and corresponds to, for example, a water level sensor or a water pressure detector. The water supply electromagnetic valve 9 is an electromagnetic valve for supplying water to the fuel cell unit 101, and water flowing from the water supply source through the hot water storage unit 102 and the exhaust heat recovery circuit 2 is supplied to the exhaust heat recovery pump 3 and the water supply electromagnetic valve 9. In order, the fuel cell unit 101 is supplied to the internal circulation circuit 5.

  The exhaust heat recovery circuit 2 is a circuit for storing the heat recovered from the internal heat circulation circuit 5 through the heat exchanger in the hot water storage tank 1. The exhaust heat recovery pump 3 is installed between the hot water storage tank 1 and the water supply electromagnetic valve 9 and guides the water below the hot water storage tank 1 to the heat exchanger via the exhaust heat recovery circuit 2 to recover the exhaust heat accompanying power generation. Let the hot water storage tank 1 store hot water.

  The controller 4 controls the operation of the auxiliary equipment of the fuel cell unit 101 and the auxiliary equipment of the hot water storage unit 102. The controller 4 may be installed in each of the fuel cell unit 101 and the hot water storage unit 102 to control the operation using communication means between the units, or may be provided with one controller 4 in both units. .

  The controller 4 is connected to an external operation unit, for example, a remote controller, and controls the operation of the cogeneration system by an external operation command.

  The bottom and top of the hot water storage tank 1 are connected to the exhaust heat recovery circuit 2 to recover the exhaust heat accompanying power generation and store the hot water. The water supply path 11 is connected to the bottom of the hot water storage tank 1 and supplies water to the hot water storage unit 102. The drainage path 12 is connected to the upper part of the hot water storage tank 1 and drains the water in the hot water storage unit 102.

The water supply amount detector 13 is installed in the water supply path 11 or the drainage path 12 in the hot water storage unit 102 and detects the amount of water supplied to the hot water storage unit 102. For example, by using a flow meter and integrating the detected values, the amount of water flowing into the hot water storage unit 102 during the water filling operation, that is, the amount of water filling can be detected.

  Next, FIG. 2 shows a flowchart of the control operation of the controller 4 in the water filling operation control of the cogeneration system according to the first embodiment.

  When a water filling operation instruction is issued by the operation unit, the controller 4 instructs the hot water storage unit 102 to fill with water, and water filling of the hot water storage unit 102 is started (STEP 1). In STEP 1, water is supplied from the water supply path 11 to the hot water storage unit 102, and water is filled in order from the bottom of the hot water storage tank 1.

  When the water filling operation of the hot water storage unit 102 is started, the water supply electromagnetic valve 9 in the fuel cell unit 101 is opened (STEP 2). At this time, the water flowing into the hot water storage tank 1 in STEP 1 flows in the order of the exhaust heat recovery circuit 2, the exhaust heat recovery pump 3, and the water supply electromagnetic valve 9 due to the pressure gradient due to the opening of the water supply electromagnetic valve 9. It flows into the unit 101. Water flowing into the fuel cell unit 101 passes through the internal circulation circuit 5 and accumulates in the internal tank 7.

  Wait until the internal tank water amount detector 8 detects that water has accumulated (STEP 3). When it is detected by the internal tank water amount detector 8 that water has sufficiently flowed into the internal tank 7, the internal circulation pump 6 is activated to start filling the fuel cell unit 101 with water (STEP 4).

  At this time, the controller 4 sets the second time as a timer (starts measurement of the second time). The second time is a time required for water filling of the fuel cell unit 101, and is set in advance according to the volume of the water path of the fuel cell unit 101 and the capacity of the internal circulation pump 6. The internal circulation pump 6 operates until the second time elapses after the operation of the internal circulation pump 6 is started (STEP 11), and after the second time elapses after the operation of the internal circulation pump 6 is started, the internal circulation pump 6 6 stops (STEP 12).

  Next, it is detected whether or not water filling of the fuel cell unit 101 is completed (STEP 13). Here, completion of water filling of the fuel cell unit 101 may be detected by, for example, the internal tank water amount detector 8 or may be detected when the rotational speed of the internal circulation pump 6 is stabilized. Alternatively, a separate flow rate detector may be installed to detect that the flow rate of water flowing through the internal circulation circuit 5 is stable.

  In STEP 13, when the water filling of the fuel cell unit 101 is not completed, the process returns to STEP 4, the internal circulation pump 6 is operated again, and the water filling operation is retried.

  After completion of the water filling of the fuel cell unit 101, the process waits until the water filling of the hot water storage unit 102 is detected by the water supply amount detector 13 installed in either the water supply path 11 or the drainage path 12 (STEP 14).

  In STEP 13, the completion of water filling of the fuel cell unit 101 is detected. In STEP 14, the completion of water filling of the hot water storage unit is detected. ).

  As described above, the water filling of the fuel cell unit 101 and the hot water storage unit 102 can be performed without complicated work by one water filling operation instruction from the operation unit, and the total water filling time can be shortened.

  In addition, when air remains in the fuel cell unit 101 and the filling of the fuel cell unit 101 is not completed by operating the internal circulation pump 6 for the second time, the internal circulation pump 6 is operated again to Since the water filling retry operation of the battery unit 101 is performed, the air in the cogeneration system can be surely extracted.

  Further, since the fuel cell unit 101 is shifted to the starting operation upon completion of water filling of both the fuel cell unit 101 and the hot water storage unit 102, not only the water filling operation but also the total test operation time including the start-up and power generation can be shortened. it can.

(Embodiment 2)
The cogeneration system according to Embodiment 2 of the present invention has the same configuration as that of Embodiment 1 shown in FIG.

  Next, FIG. 3 shows a flowchart of the control operation of the controller 4 in the water filling operation control according to the second embodiment.

  Steps 1 to 4 are the same as those in the first embodiment. While the hot water storage unit 102 is being filled with water, the water supply electromagnetic valve 9 is opened, the internal circulation pump 6 is in an operating state, and the hot water storage unit 102 is in a standby state until the water filling operation is completed. (Step 21).

  When the filling of the hot water storage unit 102 is completed, the exhaust heat recovery pump 3 is actuated to start filling the exhaust heat recovery circuit 2 (STEP 22).

  In STEP 3, since the internal tank water amount detector 8 detects that water has surely flowed into the fuel cell unit 101, the exhaust heat recovery pump installed between the hot water storage unit 102 and the fuel cell unit 101. Since the water can surely pass through 3, even if the exhaust heat recovery pump 3 is operated in STEP 22, air is not caught, and the exhaust heat recovery circuit 2 can be reliably filled with water. .

  This operation is realized by any combination of hot water storage unit and fuel cell unit, regardless of the connection shape of the hot water storage tank 1 and the exhaust heat recovery circuit 2, because the exhaust heat recovery pump 3 is operated depending on the presence or absence of water. Is possible.

  After STEP 22, the water supply electromagnetic valve 9 is closed at a preset timing (STEP 23). The timing set in advance is a timing determined by the air entrainment state of the exhaust heat recovery pump 3, for example, the timing when the rotational speed of the exhaust heat recovery pump 3 is stabilized, or the downstream of the exhaust heat recovery pump 3. The timing at which the flow rate in the exhaust heat recovery circuit 2 is stabilized by a flow rate detector or the like is determined using a threshold value.

  When water filling of the exhaust heat recovery circuit 2 is completed, the operation of the exhaust heat recovery pump 3 is stopped (STEP 24). Completion of water filling of the exhaust heat recovery circuit 2 is detected by a timer from the operating capacity of the exhaust heat recovery pump 3 and the length of the exhaust heat recovery circuit 2. Alternatively, there is a method of detecting that the flow rate in the exhaust heat recovery circuit 2 is stabilized by a flow rate detector or the like installed in the exhaust heat recovery circuit 2.

  Wait until the water filling of the fuel cell unit 101 is completed (STEP 25). When the water filling of the fuel cell unit 101 is completed, the internal circulation pump 6 is stopped (STEP 26).

In STEP 25, the completion of water filling of the fuel cell unit 101 is detected. In STEP 21, the completion of water filling of the hot water storage unit is detected. ).

  As described above, the water filling of the fuel cell unit 101 and the hot water storage unit 102 can be performed without complicated work by one water filling operation instruction from the operation unit, and the total water filling time can be shortened.

  Further, since the exhaust heat recovery pump 3 is operated depending on the presence or absence of water, water can be reliably passed through the exhaust heat recovery pump 3, and even if the exhaust heat recovery pump 3 is operated, air is not caught and is reliably In addition, the exhaust heat recovery circuit 2 can be filled with water.

  Further, since the exhaust heat recovery pump 3 is operated depending on the presence or absence of water, it can be realized by any combination of hot water storage unit and fuel cell unit regardless of the connection shape of the hot water storage tank 1 bottom and the exhaust heat recovery circuit 2. is there.

  Further, since the fuel cell unit 101 is shifted to the starting operation upon completion of water filling of both the fuel cell unit 101 and the hot water storage unit 102, not only the water filling operation but also the total test operation time including the start-up and power generation can be shortened. it can.

(Embodiment 3)
The cogeneration system according to Embodiment 3 of the present invention has the same configuration as that of Embodiment 2.

  Next, FIG. 4 shows a flowchart of the control operation of the controller 4 in the water filling operation control according to the third embodiment.

  Steps 1 to 4 are the same as those in the first embodiment. The hot water storage unit 102 is in the water filling operation, the water supply electromagnetic valve 9 is opened, the internal circulation pump 6 is in the operating state, and waits until the first time has elapsed from the start of water filling ( (STEP 31). In the present embodiment, the controller 4 sets the first time as a timer in STEP 1 (starts measurement of the first time).

  The first time is set shorter than the time until water filling of the hot water storage unit 102 is completed, and is determined by the flow rate of water supplied to the hot water storage tank 1 and the capacity of the exhaust heat recovery pump 3, and is discharged from the hot water storage tank 1 by the exhaust heat recovery pump 3. When the amount of water to be stored is larger than the water supply flow rate to the hot water storage tank 1, the time is set so that the water in the hot water storage tank 1 does not run out.

  When the first time elapses, the exhaust heat recovery pump 3 is operated to start filling the exhaust heat recovery circuit 2 (STEP 32). At this time, the controller 4 sets the third time as a timer (starts measurement of the third time). The third time is a time set based on the operating capacity of the exhaust heat recovery pump 3 and the length of the exhaust heat recovery circuit 2, and is set in advance so that water flows stably in the exhaust heat recovery circuit 2.

  After STEP 32, the water supply electromagnetic valve 9 is closed at a preset timing (STEP 33). The timing set in advance is a timing determined by the air entrainment state of the exhaust heat recovery pump 3, for example, the timing when the rotational speed of the exhaust heat recovery pump 3 is stabilized, or the downstream of the exhaust heat recovery pump 3. The timing at which the flow rate in the exhaust heat recovery circuit 2 is stabilized by a flow rate detector or the like is determined using a threshold value.

  The exhaust heat recovery pump 3 operates until the third time elapses after the operation of the exhaust heat recovery pump 3 is started (STEP 34), and after the third time elapses after the operation of the exhaust heat recovery pump 3 is started, The exhaust heat recovery pump 3 stops (STEP 35).

  Here, in STEP32 to 35, the air in the exhaust heat recovery circuit 2 may flow to the upper part of the hot water storage tank 1. In order to prevent the remaining of the air, the hot water storage unit 102 is operated to discharge the air in the upper part of the hot water storage tank 1, and if the air discharge is completed, it is determined that the water filling of the hot water storage unit 102 is completed (STEP 36). The hot water storage unit 102 discharges air from the drainage path 12.

  When the water supply amount detector 13 installed in the drainage path 12 drains while air is mixed, the flow rate becomes unstable. When it is detected that a stable flow rate is flowing, the process proceeds to STEP38. If the flow rate fluctuation is large or if it has not stabilized for a certain period of time, it is determined that the hot water tank upper air discharge has failed and the process proceeds to STEP 37.

  When air remains in the upper part of the hot water storage tank 1, when hot water is supplied with the water in the hot water storage tank 1, it becomes hot water mixed with air, or the mixed flow of air causes the flow rate to become unstable and the hot water supply temperature to become unstable. Since an abnormality may occur, the water filling completion state of the hot water storage unit 102 is regarded as incomplete, and the water filling operation control is retried (STEP 37). Therefore, the air filling operation is performed again, so that air does not remain reliably in the cogeneration system.

  The internal circulation pump 6 operates until the water filling of the fuel cell unit 101 is completed (STEP 38), and when completed, the internal circulation pump 6 stops (STEP 39).

  In step 38, the completion of water filling of the fuel cell unit 101 is detected. In step 36, the completion of water filling of the hot water storage unit is detected. ).

  As described above, the water filling of the fuel cell unit 101 and the hot water storage unit 102 can be performed without complicated work by one water filling operation instruction from the operation unit, and the total water filling time can be shortened.

  Further, since the exhaust heat recovery pump 3 is operated depending on the presence or absence of water, water can be reliably passed through the exhaust heat recovery pump 3, and even if the exhaust heat recovery pump 3 is operated, air is not caught and is reliably In addition, the exhaust heat recovery circuit 2 can be filled with water.

  Further, since the exhaust heat recovery pump 3 is operated depending on the presence or absence of water, it can be realized by any combination of hot water storage unit and fuel cell unit regardless of the connection shape of the hot water storage tank 1 bottom and the exhaust heat recovery circuit 2. is there.

  Further, since the water filling operation control is not completed until the air flowing into the hot water storage unit 102 is discharged due to the water filling of the exhaust heat recovery circuit 2, the water filling can be completed in a state where the air is surely removed from the cogeneration system.

  Further, since the fuel cell unit 101 is shifted to the start-up operation upon completion of water filling of both the fuel cell unit 101 and the hot water storage unit 102, not only the water-filling operation but also the total test operation time including start-up and power generation can be shortened. it can.

(Embodiment 4)
FIG. 5 is a configuration diagram of a cogeneration system according to Embodiment 4 of the present invention.

  As shown in FIG. 5, in the cogeneration system according to the fourth embodiment of the present invention, a fuel processor 21, a reforming water path 22, and a reforming water pump 23 are added to the configuration of the second embodiment.

  The fuel processor 21 produces hydrogen to be used for the power generation operation of the fuel cell unit 101 from a raw material and reformed water by a reforming reaction.

  The reforming water path 22 is a circuit for supplying the reforming water used for steam reforming from the internal tank 7 to the fuel processor 21.

  The reforming water pump 23 is a pump that supplies the fuel processor 21 from the internal tank 7, is installed in the reforming water path 22, and changes its output by the controller 4 in the reforming control.

  Next, FIG. 6 shows a flowchart of the control operation of the controller 4 in the water filling operation control of the cogeneration system according to the fourth embodiment.

  When a water filling operation instruction is issued by the operation unit, the controller 4 instructs the hot water storage unit 102 to close the valve, and the paths other than the exhaust heat recovery circuit 2 and the water supply path 11 among the paths communicating with the hot water storage tank 1 are closed. (STEP 41). In STEP 41, tap water is supplied from the water supply path 11 to the hot water storage unit 102, and water flows in in order from the bottom of the hot water storage tank 1.

  When the hot water storage tank 1 receives the valve closing instruction, the water supply electromagnetic valve 9 in the fuel cell unit 101 is opened (STEP 42). At this time, the water that flows into the hot water storage tank 1 in STEP 1 is closed in the path that is connected to the hot water storage tank 1 and the exhaust heat recovery circuit 2 and the water supply path 11 among the paths that are connected to the hot water storage tank 1. Due to this pressure gradient, the exhaust heat recovery circuit 2, the exhaust heat recovery pump 3, and the water supply electromagnetic valve 9 flow in this order and flow into the fuel cell unit 101. The water that has flowed into the fuel cell unit 101 accumulates in the internal tank 7.

  In the present embodiment, since the route excluding the exhaust heat recovery circuit 2 and the water supply route 11 among the routes communicating with the hot water storage tank 1 is closed, a larger pressure gradient (water supply water pressure applied to the hot water storage tank 1). As a result, the time during which water flows into the fuel cell unit 101 and the water accumulates in the internal tank 7 is shortened.

  After opening the water supply electromagnetic valve 9 in STEP 42, the process waits until the internal tank water amount detector 8 detects that water has accumulated in the internal tank 7 (STEP 50). When it is detected by the internal tank water amount detector 8 that water has sufficiently flowed into the internal tank 7, the internal circulation pump 6 is actuated to start filling the internal circulation circuit 5 (STEP 51), and the reforming water pump 23 is turned on. The operation is started and water filling of the reforming water path 22 is started (STEP 61), water filling instruction is given to the hot water storage unit 102, and water filling of the hot water storage unit 102 is started (STEP 71).

  After operating the internal circulation pump 6 in STEP 51, it is detected whether or not water filling of the internal circulation circuit 5 is completed (STEP 52). Here, completion of water filling in the internal circulation circuit 5 may be detected by, for example, the rotation speed of the internal circulation pump 6 being stabilized, or may be detected by operating a preset time. Alternatively, a separate flow rate detector may be installed to detect that the flow rate of water flowing through the internal circulation circuit 5 is stable.

  When it is detected in STEP 52 that the water filling of the internal circulation circuit 5 has been completed, the internal circulation pump 6 is stopped (STEP 53).

After the reforming water pump 23 is operated in STEP 61, it is detected whether or not the water filling of the reforming water path 22 is completed (STEP 62). Here, completion of the water filling of the reforming water path 22 may be detected, for example, by detecting that the rotation speed of the reforming water pump 23 has been stabilized, or by operating a preset time. . Alternatively, a separate flow rate detector may be installed to detect that the flow rate of water flowing through the reforming water path 22 is stable.

  When it is detected in STEP 62 that the water filling of the reforming water path 22 is completed, the reforming water pump 23 is stopped (STEP 63).

  After starting the water filling of the hot water storage unit 102 in STEP 71, the exhaust heat recovery pump 3 is operated to start the water filling of the exhaust heat recovery circuit 2 (STEP 72).

  In STEP 50, the internal tank water amount detector 8 detects that water has surely flowed into the fuel cell unit 101, and therefore, the exhaust heat recovery pump installed between the hot water storage unit 102 and the fuel cell unit 101. Since the water can surely flow through the exhaust heat recovery circuit 3, even if the exhaust heat recovery pump 3 is operated in STEP 72, air is not caught and the exhaust heat recovery circuit 2 can be reliably filled with water. .

  This operation is realized by any combination of hot water storage unit and fuel cell unit, regardless of the connection shape of the hot water storage tank 1 and the exhaust heat recovery circuit 2, because the exhaust heat recovery pump 3 is operated depending on the presence or absence of water. Is possible.

  After STEP 72, the water supply electromagnetic valve 9 is closed at a preset timing (STEP 73). The timing set in advance is a timing determined by the air entrainment state of the exhaust heat recovery pump 3, for example, the timing when the rotational speed of the exhaust heat recovery pump 3 is stabilized, or the downstream of the exhaust heat recovery pump 3. The timing at which the flow rate in the exhaust heat recovery circuit 2 is stabilized by a flow rate detector or the like is determined using a threshold value.

  After the water supply electromagnetic valve 9 is closed in STEP 73, it is detected whether or not the water filling of the exhaust heat recovery circuit 2 is completed (STEP 74). Here, completion of water filling of the exhaust heat recovery circuit 2 may detect, for example, that the rotation speed of the exhaust heat recovery pump 3 has been stabilized by the rotation speed, or the operating capacity of the exhaust heat recovery pump 3 and the exhaust heat recovery circuit 2. It may be detected by a timer from the length of. Alternatively, a separate flow rate detector may be installed to detect that the flow rate of water flowing through the exhaust heat recovery circuit 2 is stable.

  When it is detected in STEP 74 that the filling of the exhaust heat recovery circuit 2 is completed, the exhaust heat recovery pump 3 is stopped (STEP 75).

  After completion of water filling of the exhaust heat recovery circuit 2, the system waits until the water filling of the hot water storage unit 102 is completed by the water supply amount detector 13 installed in either the water supply path 11 or the drainage path 12 (STEP 76).

  After opening the water supply electromagnetic valve 9 in STEP42, it is detected in STEP43 whether or not the water filling operation of the internal circulation circuit 5 is completed. When it is detected that the water filling operation of the internal circulation circuit 5 is completed, the fuel cell unit 101 is activated. The process proceeds to the preparation operation (STEP 44). The start preparation operation is a preparatory operation before the fuel cell unit 101 shifts to the start operation. The water leak check of the internal tank 7, the operation check of the electromagnetic valve in the fuel cell unit 101, and the fuel cell unit 101 This refers to a preparatory operation irrespective of the water filling state of the exhaust heat recovery circuit 2, the reforming water path 22, and the hot water storage unit 102, such as an operation check of the connected CT.

When the start preparation operation is completed and the completion of water filling of the reforming water path 22 and the exhaust heat recovery circuit 2 is detected in STEP 45, the fuel cell unit 101 shifts to the start operation (STEP 46). The start-up operation includes a temperature raising operation of the fuel processor 21 for generating power by the fuel cell unit 101, a hydrogen generation reaction in the fuel processor 21, and the like. When the temperature raising operation involves combustion, in order to cool the exhaust gas, the water filling of the exhaust heat recovery circuit 2 needs to be completed and the water filling of the reforming water path 22 needs to be completed for the hydrogen generation reaction.

  When the start-up operation is completed and the completion of water filling of the hot water storage unit 102 is detected in STEP 47, the fuel cell unit 101 shifts to the power generation operation (STEP 99).

  As described above, the water filling of the fuel cell unit 101 and the hot water storage unit 102 can be performed without complicated work by one water filling operation instruction from the operation unit, and the total water filling time can be shortened.

  In addition, since the fuel cell unit 101 shifts to the start preparation operation, the start operation, and the power generation operation with only a minimum water filling completion state, it is not necessary that both the fuel cell unit 101 and the hot water storage unit 102 have been water filled. In addition to water filling operation, the total test run time including start-up and power generation can be shortened.

  As described above, the cogeneration system of the present invention performs water filling of the hot water storage unit, the exhaust heat recovery circuit, and the fuel cell unit at the same time without leaving air in the system with a simple operation regardless of the type of the hot water storage unit. This makes it possible to shorten the total water filling time and is optimal for a household fuel cell cogeneration system.

DESCRIPTION OF SYMBOLS 1 Hot water storage tank 2 Waste heat recovery circuit 3 Waste heat recovery pump 4 Controller 5 Internal circulation circuit 6 Internal circulation pump 7 Internal tank 8 Internal tank water quantity detector 9 Water supply solenoid valve 11 Water supply path 12 Drainage path 13 Water supply quantity detector 21 Fuel Processor 22 Reformed water path 23 Reformed water pump 101 Fuel cell unit 102 Hot water storage unit

Claims (12)

A fuel cell unit that generates electricity and heat by generating electricity;
A hot water storage unit comprising a hot water storage tank for storing heat of the fuel cell unit;
An exhaust heat recovery circuit for supplying the water in the hot water storage tank to the fuel cell unit and recovering the exhaust heat of the fuel cell unit, and then returning it to the hot water storage tank;
An internal circulation circuit that circulates and cools water inside the fuel cell unit;
An internal circulation pump disposed in the internal circulation circuit;
An internal tank for storing internally circulated water disposed in the internal circulation circuit;
An internal tank water amount detector capable of detecting the amount of water in the internal tank;
A water supply solenoid valve that opens and closes in order to flow and block a passage for supplying water of the exhaust heat recovery circuit to the internal circulation circuit;
A controller, and
When the controller supplies water to the hot water storage tank and starts a water filling operation, the controller opens the water supply electromagnetic valve,
A cogeneration system that controls to start the operation of the internal circulation pump when the internal tank water amount detector detects that water has flowed into the fuel cell unit. A water supply amount detector for detecting the amount of water supplied to the hot water storage unit;
An exhaust heat recovery pump disposed in the exhaust heat recovery circuit,
The exhaust heat recovery pump is installed downstream of the hot water storage tank and upstream of the water supply solenoid valve,
The controller controls to start the operation of the exhaust heat recovery pump when the water supply detector detects completion of water filling of the hot water storage unit,
The cogeneration system according to claim 1. An exhaust heat recovery pump disposed in the exhaust heat recovery circuit;
The exhaust heat recovery pump is installed downstream of the hot water storage tank and upstream of the water supply solenoid valve,
The controller controls to start the operation of the exhaust heat recovery pump when a first time has elapsed since the start of the water filling operation.
The cogeneration system according to claim 1. The controller starts activation of the fuel cell unit when the water supply amount detector detects completion of water filling of the hot water storage unit and the internal tank water amount detector detects completion of water filling of the fuel cell unit. The cogeneration system according to claim 2, which is controlled as follows. The controller operates the internal circulation pump again when the internal tank water amount detector does not detect completion of water filling of the fuel cell unit after operating the internal circulation pump for a preset second time. The cogeneration system according to any one of claims 1 to 4, wherein the cogeneration system is controlled as follows. A water supply detector installed in a drainage path connected to the upper part of the hot water storage tank;
If the controller does not detect completion of water filling of the hot water storage unit by the water supply amount detector after operating the exhaust heat recovery pump for a preset third time, the controller performs water filling operation of the hot water storage unit again. The cogeneration system according to claim 3, wherein the cogeneration system is controlled as follows. A water supply path for supplying tap water to the bottom of the hot water storage tank;
The controller closes a path excluding the exhaust heat recovery circuit and the water supply path among paths communicating with the hot water storage tank, then opens the water supply electromagnetic valve, and supplies a water supply pressure of the water supply to the hot water storage tank. The cogeneration system according to claim 1, wherein water is passed through the internal tank. An exhaust heat recovery pump disposed in the exhaust heat recovery circuit;
The exhaust heat recovery pump is installed downstream of the hot water storage tank and upstream of the water supply solenoid valve,
The controller controls the start of the operation of the exhaust heat recovery pump after the internal tank water amount detector detects that water has flowed into the fuel cell unit.
The cogeneration system according to claim 7. A fuel processor for producing hydrogen used for power generation operation of the fuel cell unit from a raw material and reformed water by a reforming reaction;
A reforming water path for supplying water from the internal tank as the reforming water to the fuel processor, and a reforming water pump disposed in the reforming water path,
9. The controller according to claim 1, wherein when the internal tank water amount detector detects that water has flowed into the fuel cell unit, the controller controls to start the operation of the reforming water pump. Cogeneration system described in 1. The cogeneration system according to any one of claims 1 to 9, wherein when the controller detects that the water filling of the internal circulation circuit has been completed, the controller controls to start a start-up preparation operation of the fuel cell unit. . A fuel cell unit that generates electricity and heat by generating electricity;
A hot water storage unit comprising a hot water storage tank for storing heat of the fuel cell unit;
An exhaust heat recovery circuit for supplying the water in the hot water storage tank to the fuel cell unit and recovering the exhaust heat of the fuel cell unit, and then returning it to the hot water storage tank;
An internal circulation circuit that circulates and cools water inside the fuel cell unit;
An internal circulation pump disposed in the internal circulation circuit;
An internal tank for storing internally circulated water disposed in the internal circulation circuit;
An internal tank water amount detector capable of detecting the amount of water in the internal tank;
A water supply solenoid valve that opens and closes in order to flow and block a passage for supplying water of the exhaust heat recovery circuit to the internal circulation circuit;
A cogeneration system operation method comprising:
When supplying water to the hot water storage tank and starting a water filling operation, opening the water supply solenoid valve;
When the internal tank water amount detector detects that water has flowed into the fuel cell unit, starting the operation of the internal circulation pump;
Cogeneration system operation method with A fuel cell unit that generates electricity and heat by generating electricity;
A hot water storage unit comprising a hot water storage tank for storing heat of the fuel cell unit;
An exhaust heat recovery circuit for supplying the water in the hot water storage tank to the fuel cell unit and recovering the exhaust heat of the fuel cell unit, and then returning it to the hot water storage tank;
An internal circulation circuit that circulates and cools water inside the fuel cell unit;
An internal circulation pump disposed in the internal circulation circuit;
An internal tank for storing internally circulated water disposed in the internal circulation circuit;
An internal tank water amount detector capable of detecting the amount of water in the internal tank;
A water supply solenoid valve that opens and closes in order to flow and block a passage for supplying water of the exhaust heat recovery circuit to the internal circulation circuit;
A water supply path for supplying tap water to the bottom of the hot water storage tank;
A cogeneration system operation method comprising:
When supplying water to the hot water storage tank and starting a water filling operation, among the paths communicating with the hot water storage tank, the path excluding the exhaust heat recovery circuit and the water supply path is closed, and then the water supply electromagnetic valve is opened. Passing water into the internal tank by a water supply pressure applied to the hot water storage tank;
When the internal tank water amount detector detects that water has flowed into the fuel cell unit, starting the operation of the internal circulation pump;
Cogeneration system operation method with

Images