JP4942386B2 - Power generation / hot water cogeneration system - Google Patents

Description

  The present invention relates to a power generation / hot water cogeneration system including a fuel cell device and a hot water supply device, and more particularly to a power generation / hot water cogeneration system including a fuel cell device including a solid electrolyte fuel cell and a hot water supply device including a hot water storage tank.

  In recent years, a power supply system using a fuel cell has attracted attention as a power source for moving bodies such as automobiles or a power source for residential use such as homes, and has been actively developed. Household fuel cells have been developed as a power generation / hot water cogeneration system that can supply hot water at the same time as supplying household electric power. Until now, households have used electricity generated at power plants and generated heat at home for use. For this reason, there has been a problem that heat generated during power generation at the power plant is not effectively utilized. The power generation / hot water cogeneration system can generate electricity at home, and can be used effectively by storing the heat generated at that time. The type of fuel cell used for household fuel cells is called a solid polymer type, and the electrolyte is made of a polymer and has proton conductivity. The operating temperature of the fuel cell itself is about 80 ° C., and only hydrogen is used as the fuel that contributes to power generation.

  In this household fuel cell, a hydrocarbon-based fuel such as city gas or propane at home is generally used as a fuel instead of hydrogen. For this reason, complicated fuel processing steps are required. First, the hydrocarbon fuel used in these households uses a sulfur component as an odorant. This sulfur component adversely affects the fuel cell electrode. For this reason, the sulfur content is removed by a device called a desulfurizer filled with a desulfurization catalyst. Thereafter, pure water made from desulfurized fuel and tap water or water vapor generated by power generation and water are mixed in a gaseous state, and the atmosphere is around 700 ° C. filled with a reforming catalyst called a reformer. It is sent to. This reformer generates main component hydrogen, subcomponent carbon dioxide, and carbon monoxide from a hydrocarbon fuel and water vapor. The reformed gas also includes unreacted hydrocarbons and steam.

  Producing hydrogen from a hydrocarbon-based fuel as described above is called reforming, and reforming methods include methods called steam reforming, partial oxidation reforming, and autothermal reforming. The above-described reforming corresponds to steam reforming and is the reforming method having the highest energy efficiency. Although most of the fuel can be converted to hydrogen by the reformer, it cannot be put into the polymer electrolyte fuel cell as it is. This is because carbon monoxide, which is a subcomponent, adversely affects the electrode of the polymer electrolyte fuel cell and deteriorates the performance of the fuel cell.

  Therefore, a reaction called shift reaction is used to convert carbon monoxide and water vapor into carbon dioxide and hydrogen. The remaining carbon monoxide is converted to carbon dioxide by a CO selective oxidation reaction. In these processes, carbon monoxide is reduced to the order of ppm, and after that, it can be used for the first time as a fuel for a polymer electrolyte fuel cell. The fuel containing a large amount of hydrogen and the air sent by a blower or the like react in a plurality of solid polymer fuel cells connected in series and parallel, thereby generating DC power. This DC power is converted into AC power by a DC / AC inverter and connected to a power system in the home. After that, it is consumed by electric devices such as televisions, refrigerators and washing machines in the home. In some cases, a backup power source is provided in preparation for sudden load fluctuations or operation of the auxiliary equipment during a power failure. Various functions have been added to the connection with the system in preparation for accidents such as load fluctuations and power outages (for example, Patent Document 1).

Japanese Patent Laid-Open No. 2005-5213

  On the other hand, since the polymer electrolyte fuel cell uses a polymer membrane, it is necessary to suppress the operating temperature to about 80 ° C., and it is necessary to flow cooling water circulating inside the fuel cell. Since the temperature of this cooling water rises, it is stored in a hot water tank or heat exchange is performed between this cooling water and tap water. In addition to this, hot water is stored in a hot water tank by heat exchange or combustion with off-gas of the fuel cell, or heat exchange with exhaust gas of combustion of the reformer. Hot water of 70 ° C is stored in the hot water storage tank, and it is used as hot water required for home baths. In addition, it is necessary to provide a hot water heater for additional cooking in case the hot water is used excessively and the hot water in the hot water tank is exhausted.

  However, the conventional power generation / hot water cogeneration system includes a power generation unit including a power generation unit, a reforming unit, a fuel processing unit, and a gas supply unit, a hot water storage tank, a backup boiler, and a humidification unit for a fuel cell. Since it is composed of a hot water storage unit, it is large and has a problem in installation.

  In view of the above problems, the present invention divides a conventional power generation / hot water cogeneration system into a plurality of units, enables a small and wall-mountable home use, and provides a power generation / hot water cogeneration system excellent in installation and maintenance. The issue is to supply.

In order to solve the above problems, the present invention has the following features.
The present invention of claim 1 includes at least a power generation unit and the solid oxide fuel cell is accommodated in a container, a plurality of the vertical direction accumulated and axial hot water heated by exhaust heat recovery of the power generation unit A hot water storage tank comprising a pipe and a water heater for replenishing hot water when the hot water in the hot water tank is insufficient, and the hot water storage tank and the water heater are installed separately. This is a power generation / hot water cogeneration system.
In such a power generation / hot water cogeneration system, the power generation unit, the hot water tank, and the water heater are separately installed, so that the installation space is reduced, and the adaptability to the installation location for home use is expanded. Furthermore, since the hot water storage tank is installed independently, there is no influence on the gas supply section or the electrical equipment section of the power converter when water leakage occurs.
In such a power generation / hot water cogeneration system, the hot water storage tank is, for example, a plurality of substantially cylindrical pipes, and therefore can be installed using gaps.

According to a second aspect of the present invention, the power generation unit includes a supply unit that supplies a fuel gas, an oxygen-containing gas, and water to the fuel cell, and an exhaust heat recovery unit that recovers the exhaust heat discharged from the fuel cell. 2. The power generation / hot water cogeneration system according to claim 1, wherein the container includes power conversion means for converting electric power generated in the fuel cell into AC power and connecting the power to the power system.
In such a power generation / hot water cogeneration system, in addition to the fuel cell, gas supply means, exhaust heat recovery means, power conversion means, etc. are housed in the same power generation unit container, so the installation space is further reduced. , Compatibility with the place where it is installed for home use is expanded.

The present invention according to claim 3 is the power generation / hot water cogeneration system according to claim 1 or 2 , wherein the hot water storage tank is configured such that upper and lower portions of the pipes are connected by piping. is there.
In such a power generation / hot water cogeneration system, the amount of hot water stored in the hot water storage tank can be flexibly handled by increasing or decreasing the number of pipes.
The present invention according to claim 4, wherein the hot water storage tank has an upper of the one pipe, and a lower portion of the other pipe according to claim 1 or 2, characterized in that it is connected by a pipe This is a power generation / hot water cogeneration system.
In such a power generation / hot water cogeneration system, hot water storage pipes are used in series, so that hot water and water are easily stored in two upper and lower layers (stratified state). Since only the hot water in the upper part can be taken out from the hot water storage tank when hot water supply is necessary, a relatively small capacity hot water storage tank can be used efficiently. When it is necessary to suppress the height of the container for storing the hot water tank, it is effective to use pipes for hot water storage in series.

A fifth aspect of the present invention is the power generation / hot water cogeneration system according to any one of the first to fourth aspects, wherein the hot water storage tank is a vacuum heat insulating pipe.
In such a power generation / hot water cogeneration system, even if a plurality of pipes are installed as hot water storage tanks to increase the surface area, heat dissipation can be prevented by using vacuum heat insulating pipes.

According to a sixth aspect of the present invention, in the power generation according to any one of the first to fifth aspects, the container includes a front part having a removable lid and a lateral part that can be fixed.・ It is a hot water supply cogeneration system.
In such a power generation / hot water cogeneration system, since the container for storing the power generation unit can be a wall-mounted type, etc., it is easy to install, and the front lid can be removed, so that maintainability is improved. be able to.
The present invention according to claim 7, together with the hot water tank is provided with a hot water storage tank container to be housed, claims 1 to, wherein the power generating unit to the hot water tank housing on the container is provided 6. A power generation / hot water cogeneration system according to claim 6.
In such a power generation / hot water cogeneration system, a hot water storage container for storing a hot water storage tank also serves as a frame, and a power generation unit is installed thereon. Therefore, the piping for recovering the hot water existing between the power generation unit and the hot water tank can be shortened. It is also possible to store hot water recovery piping connecting between the power generation unit and the hot water storage tank in the respective containers of the power generation unit and the hot water storage tank.
The present invention is claimed in claim 8, wherein the air around the fuel cell, power generation and hot water supply cogeneration system according to claim 7, characterized by comprising an air introducing means for introducing into the hot water storage tank storing container It is.
In such a power generation / hot water cogeneration system, since the solid oxide fuel cell is stored in the power generation unit, the heated air around the fuel cell is introduced into the hot water storage container to store the hot water storage Heat loss in the tank can be reduced. At this time, if the respective containers of the hot water storage tank and the power generation unit are connected, the heat of the power generation unit can be easily drawn into the container in which the hot water storage tank is stored.
The present invention according to claim 9 is the power generation / hot water cogeneration system according to claim 7 or 8 , wherein the hot water storage tank supports an upper surface in the hot water storage tank storage container.
In such a power generation / hot water cogeneration system, the hot water tank itself has a strength to receive the weight of the power generation unit. As a result, there is no need to separately provide a strong frame in the hot water storage container of the hot water storage tank. Originally, hot water storage tanks are required to have the strength to receive water pressure, so it is common to use a cylindrical shape, but in order to support the load from above, for example, a ribbed cylindrical structure or a square structure Will do. In addition, since the frame can be omitted, the internal volume of the hot water storage tank can be increased with the same outer dimensions of the hot water storage tank.

  The power generation / hot water cogeneration system of the present invention separates and installs the hot water storage tank and hot water heater, making it easy to install for home use, flexibly adapting to the amount of hot water stored in the hot water storage tank, and improving maintainability Can be made.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic configuration diagram showing a power generation / hot water cogeneration system which is an example of the present invention. The power generation / hot water cogeneration system of the present invention uses a solid oxide fuel cell as the fuel cell 1. As the oxygen source necessary for the fuel cell 1 and the gas serving as the fuel, city gas, propane gas, and the like in the home are supplied by the blower 11.
As an air supply source, there is a compressor or the like. However, in a small fuel cell system for home use such as the present invention, the power loss of the auxiliary machine can be reduced by using a rotating blower with low power consumption.

  The blower 11 is desirably capable of supplying an air flow rate in the range of 0 to 120 L / min per 1 kW output in a solid oxide fuel cell, for example. The actual amount of air required for the reaction of the fuel cell is about 0 to 60 L / min per 1 kW system. However, in the system using the solid oxide fuel cell, it is necessary to have a cooling function of the fuel cell because of its high temperature operation. There is. For this reason, the capacity | capacitance which can supply more air flow volume required for electric power generation is required. The air supply pressure of the blower 11 is preferably as high as possible. However, since power consumption generally increases, the supply pressure is 2 kPa or less in order to make it about 1/3 or less of the power consumption of all devices.

  Here, the pressure is not defined, but if it is selected with a commercially available product from the relationship with the power consumption, such a pressure range is unavoidable. For this reason, the pressure loss of the air flow path of the fuel cell device itself is configured to be 2 kPa or less. Moreover, the air blower 11 may be a filter that removes dust, or a mesh-like air inlet that does not bob the air inlet with large-sized dust such as leaves. Further, in an environment different from that of a general home, for example, in an environment such as a coastal area or a region where there is a lot of rain or snow, a filter or an air inlet corresponding to the environment may be attached. The flow rate control of the blower 11 may be performed by changing the frequency of electric power for determining the number of rotations with a device such as an inverter, or changing the current value or voltage value of the power source.

The air generated by the blower 11 is supplied to the fuel cell 1 via the flow meter 12. The flow meter 12 is used for detecting the air flow rate. The rotational speed of the blower 11 is defined based on the flow rate instruction value and this value. Further, the flow meter 12 can be not used by obtaining the relationship between the rotational speed of the blower 11 and the air flow rate in advance. In this case, it is possible to control without using the flow meter 12 by storing the relationship between the flow rate and the rotational speed in a storage device or the like, sensing the temperature and controlling the rotational speed with software.
Furthermore, the air through the flow meter 12 may be branched before entering the fuel cell 1 or may be branched inside the fuel cell 1 depending on the configuration of the fuel cell 1. A fuel cell has a minimum unit of power generation called a cell, and a bundle of a plurality of these units is called a stack and becomes a single unit. Air may be supplied for each unit.

  The fuel gas such as city gas and propane in each household is first supplied to the cutting valve 13 through a pipe. This cut-off valve 13 is basically closed while the fuel cell 1 is not operating, and is open while it is operating. While being closed, fuel gas is not supplied to the fuel cell 1. The cutoff valve 13 can also be used at the time of emergency stop when an abnormal situation occurs in the fuel cell 1. Since the supply pressure of the city gas is about 2 kPa, it is better that the cutoff valve 13 can shut out the gas with respect to the supply pressure higher than that. Further, the function of the cutoff valve 13 can be incorporated into the flow rate control 14, and it is sufficient that the gas can be shut off by setting the flow rate to zero. The fuel gas that has flowed in through the cutoff valve 13 is controlled to a gas flow rate suitable for the fuel cell 1 in the flow rate control 14 and supplied to the fuel cell 1.

  The flow rate control 14 senses the flow rate like a mass flow controller and controls to match the indicated value, or the flow rate is detected separately, and the solenoid valve like a solenoid valve is opened and closed proportionally to control the flow rate. It may be controlled. Alternatively, it may be a flow rate control device having a boosting function. In this case, since the pressure is increased by the pump function, the flow rate may be controlled according to the rotation speed. A device that cannot detect the flow rate from itself or from the outside can also be used by obtaining the relationship between the degree of opening and closing of the flow rate control valve and the fuel flow rate in advance. In this case, the flow rate and the opening degree signal are stored in the storage device, and the control can be performed without obtaining the fuel flow rate by software from the configuration such as the temperature, the deterioration rate, and the hysteresis of the opening degree.

  The fuel whose flow rate is controlled by the flow rate control 14 may be branched before entering the fuel cell 1 according to the configuration of the fuel cell 1, or may be branched inside thereof. The branch of the fuel gas may be provided with a flow rate control valve fixed so that a predetermined amount of flow flows, or a flow path design may be made so that the flow rate distribution becomes a predetermined amount. Alternatively, a plurality of flow rate controls 14 may be mounted and the flow rate may be controlled for each flow path.

Next, as the steam used for reforming, tap water in each household is used, and is first supplied to the cutting valve 13 through a pipe. At this time, the household water pressure fluctuates from several atmospheric pressures to about 5 atmospheric pressures, and may be reduced to a constant pressure by a pressure reducing valve.
The cutoff valve 15 is basically closed while the fuel cell 1 is not operating, and water is not supplied to the fuel cell 1. The cut-off valve 15 enables tap water to be shut off against a differential pressure higher than that of the pressure reducing valve. The cutoff valve 15 can also incorporate its function in the flow control 17. The tap water that has passed through the cutoff valve 15 is filtered into pure water by the water purifier 16.
The water purifier 16 is composed of a filter, activated carbon, ion exchange resin or the like, and removes dust, chlorine and other mineral components contained in tap water. The water purifier 16 can be configured to correspond to the district so that the state of the tap water in each district is different.

The tap water that has passed through the cutoff valve 15 is controlled at a flow rate appropriate for the fuel cell 1 by the flow rate control 17 and is supplied to the fuel cell 1.
Controls to match the indicated value while sensing the flow rate like a mass flow controller, or controls flow rate separately by detecting the flow rate and proportionally opening and closing the solenoid valve like a solenoid valve. There may be. Alternatively, it may be a flow rate control device having a boosting function. In this case, since the pressure is increased by the pump function, the flow rate may be controlled according to the rotation speed.
A device that cannot detect the flow rate from itself or from the outside can also be used by obtaining the relationship between the degree of opening and closing of the flow rate control valve and the fuel flow rate in advance. In this case, the relationship between the flow rate and the opening signal is stored in the storage device, and control is possible without obtaining the fuel flow rate by software from the configuration such as temperature, deterioration rate, opening hysteresis, etc. .

  The flow rate control unit 17 controls the flow rate so as to match the indicated value while sensing the flow rate flowing like a mass flow controller, or the flow rate is detected separately, and the electromagnetic valve is opened and closed proportionally like a solenoid valve. It may be one that controls. You may come to send water by a rotary type like a pump. A device that cannot detect the flow rate from itself or from the outside can be used by obtaining the relationship between the degree of opening and closing of the flow rate control valve and the flowing water flow rate in advance. In this case, the relationship between the flow rate and the opening signal is stored in the storage device, and control is possible without obtaining the fuel flow rate with software from the configuration of temperature, deterioration rate, opening hysteresis, etc. is there.

The water whose flow rate is controlled by the flow rate control 17 may be branched before entering the fuel cell 1 according to the configuration of the fuel cell 1, or may be branched inside. The branch of the fuel gas may be provided with a flow control valve fixed so that a predetermined amount of flow flows, or a flow path may be designed so that the flow distribution becomes a predetermined amount. A plurality of flow rate controls 17 may be mounted to control the flow rate for each flow path.
The water introduced into the fuel cell 1 through the flow rate control 17 is vaporized in the fuel cell or in an adjacent region, and is supplied as steam to the reforming unit. This water vapor is configured to be mixed with fuel gas before being supplied to the reforming section. Basically, it should be mixed in the vaporizing section. This is because the vaporized water vapor is transported by the fuel gas as a carrier, so that the vaporized water vapor can be efficiently carried.

  The structure of this vaporizer may be a double pipe structure in which water and fuel may flow through each pipe, or a space for vaporization is provided, and a large heat capacity, for example, a ceramic ball is placed to generate heat of vaporization. However, the temperature change is small and the gas can be sufficiently vaporized, and the fuel gas may flow through the space and be carried into the reformer as a carrier.

  Furthermore, it is also possible to configure a system that does not require the cutting valve 15, the water purifier 16, and the flow rate control 17 by making the water vapor in the exhaust gas from the fuel cell 1 or the fuel gas unreacted with the water vapor into an ejector structure. is there. This ejector structure is a structure in which fuel gas is blown from a nozzle. When the injected fuel gas passes through the off-gas, a predetermined amount of off-gas is entrained in the fuel gas, and water vapor, unreacted reaction gas and Mixed. By making the amount of water vapor involved at this time an ejector structure, new water vapor, a device for vaporizing the water vapor, and tap water from which water vapor is generated are also unnecessary. Alternatively, the water vapor in the exhaust gas of the fuel cell 1 is solidified by heat exchange or the like and reused, so that the cutting valve 15 and the water purifier 16 can be reduced in size or configured as an unnecessary system.

  Since the water obtained from the exhaust gas is basically distilled water, it can be used as a water vapor source for a fuel cell without passing through a water purifier. For this reason, it becomes possible to downsize or remove the water purifier 16 by replacing part or all of the tap water used as water vapor with water obtained from the exhaust gas. In this case, since the water pressure does not work, a device for increasing the pressure such as a pump may be required.

  Further, the fuel gas supply system may be configured with a device for sending oxygen for starting or stopping. For example, the air in the atmosphere is pressurized and compressed by the pump 18 and is opened into the fuel gas by opening the cutting valve 19. The pump 18 may be provided with a filter that prevents dust from entering. The pump 18 may be configured to control the air flow rate. Further, the pump 18 may be a blower called a blower. The oxygen in the air sent by the pump 18 is used for a reforming reaction called partial oxidation reforming. This is because when the steam reforming method is used, since the temperature inside the apparatus is low at the time of start-up, the vaporized water vapor condenses in the apparatus, so that the steam necessary for steam reforming reaches the reforming section. This is because the reforming reaction does not occur. The pump 18 may continue to operate during start-up, but since steam reforming is performed during operation, when the temperature reaches a state where steam does not solidify in the apparatus in order to speed up the transition from start-up to operation. Alternatively, the operation of the pump 18 may be stopped, the cutoff valve 19 that is an electromagnetic valve may be closed to stop the supply of air, and the water vapor may be supplied. These may be used together during the transition period.

Furthermore, for example, by attaching a starter burner (not shown), the fuel cell 1 can be warmed, whereby a system that does not condense even if water vapor is supplied can be configured. In this case, the pump 18 and the cutting valve 19 can be omitted.
Furthermore, an ignition device 24 is also required as an ignition source at the time of activation. The ignition device 24 generates a high voltage, and discharge is performed at this and the ground portion, so that the fuel gas can be ignited. The ignition device 24 is disposed outside the fuel cell 1 and wired from there. A metal having strong oxidation resistance and heat resistance is used for the discharge portion. The ground portion is a metal casing portion, a piping portion, or the cell itself of the fuel cell 1 so that the portion is discharged and burned. Further, a system in which a heater is attached without using discharge and ignition is performed by the heat may be used. In this way, direct current power is generated by an electrochemical reaction inside the fuel cell 1 due to the supplied fuel, water vapor, and air through activation. Since the fuel cell is an electrochemical reaction, the direct current value and the fuel gas flow rate or air flow rate are in a proportional relationship. This is because electricity flows in the form of oxygen ions in the solid electrolyte, so that the amount of charge contained therein is proportional to the number of oxygen ions. For this reason, the required fuel gas flow rate can be obtained by measuring the current value with the ammeter 20.

  A plurality of ammeters 20 may be installed according to the number of cells connected in parallel. As the ammeter 20, a so-called shunt resistor or a shunt resistor may be used, or the ammeter 20 may be incorporated into the inverter 21 as a circuit. Further, the relationship between the DC input voltage and DC input current to the inverter 21 or the AC output voltage and AC output current from the inverter and the fuel gas flow rate, air gas flow rate and water flow rate is obtained and stored in the storage device in the control circuit. Therefore, it is possible to control by software, and the ammeter 21 can be eliminated. In this case, since the gas flow rate, the water vapor flow rate, and the air flow rate differ depending on the operating temperature of the fuel cell, it is necessary to add temperature correction.

  The DC power generated in the fuel cell 1 is supplied to the inverter 21 via the ammeter. In the inverter 21, DC power is converted into AC power. In general, since the supply voltage of the fuel cell is low, the inverter 21 may include a function for boosting this voltage. This boosting function may be a function of boosting a DC voltage called a boosting chopper, or a function of boosting as an AC voltage after being converted into AC by an inverter.

  Further, the inverter 21 may include various protective relay functions in connection with the power system. For example, there is an overvoltage relay when the voltage of the fuel cell system rises abnormally, and an undervoltage relay when the voltage of the fuel cell system drops abnormally. A relay in the event of a short circuit or ground fault in the system may also be included. When there is a reverse power flow, a frequency increase relay and a frequency decrease relay are required to prevent isolated operation, and when there is no reverse power flow, a reverse power relay and a frequency decrease relay are required to prevent isolated operation. If there are various detection functions in the system, it is possible to eliminate these relays.

The AC power output from the inverter 21 is connected as a power source for the power system and auxiliary equipment.
The battery 22 can be started at a place where there is no power at the time of start-up, or the fuel cell system is not stopped when the fuel cell system cannot follow the fluctuation of the load power or when the power system fails. It is also for. For this, it is possible to place an emphasis on cost and an unnecessary system.

  On the other hand, another hot water supply of the cogeneration system is made from tap water at home. In the power generation / hot water supply cogeneration system of the present invention, tap water is supplied to the pressure reducing valve 28 and the mixer 31. The pressure reducing valve 28 is used to make the water pressure in the hot water tank 30 constant, and is set to a water pressure of 1 to 2 atmospheres. The pressure reducing valve 28 may be installed before branching with the mixer 31. The tap water supplied through the pressure reducing valve 28 is stored in the hot water tank 30. This water can be recovered as hot water by being sent to the heat exchanger of the fuel cell 1 by the pump 29. The pump 29 exchanges heat by controlling the interval by controlling the number of revolutions or ON / OFF control according to the temperature of the heat exchanger and the power generation amount of the fuel cell 1. Since the collected hot water is stored from the upper part of the hot water storage tank, the hot water and the water can be stored in two upper and lower layers without being mixed with each other because the specific gravity of the hot water and the water is different. At this time, the temperature of hot water is about 70 to 90 ° C. in a high hot water storage region.

  Since hot water is stored in the upper part of the hot water storage tank 30 in this way, when hot water is used, it is pushed by water pressure from below, and if a drain outlet is provided above, only hot water is obtained. Moreover, since the hot water storage tank 30 is covered with the heat insulating material, there is little discharge | release of the heat from the stored hot water, and hot water can be stored for a long time at high temperature. Further, the hot water tank 30 is provided with a discharge pressure valve, and when water vapor is generated in the hot water tank by, for example, heat exchange and the pressure in the hot water tank increases, the water is automatically drained and the pressure is reduced. be able to. Furthermore, if the drain valve can be operated manually, it is convenient when draining the hot water tank 30 for maintenance or the like. Hot hot water stored in the hot water tank 30 is mixed with tap water in the mixer 31 and lowered to a predetermined temperature. Thereby, it is possible to make the temperature of hot water of about 40 to 60 ° C. sufficiently usable at home without worrying about burns or the like. Furthermore, even if it supplies to the hot water heater 32 for backup, it becomes possible to use it, without irritating an apparatus.

  Hot water mixed in the mixer 31 is supplied to the water heater 32. The hot water heater 32 is a hot water supply device for backup, and operates when the hot water in the hot water storage tank 30 runs out. When the hot water coming out of the mixer 31 has a predetermined temperature, the water heater 32 does not operate. When there is no hot water in the hot water storage tank 30 and as a result, the temperature of the hot water from the mixer 31 is lowered, the water heater 32 is activated to a predetermined temperature. The water heater 32 may not only create hot water called a single-function device, but may also have a bath preparation function, a bathroom drying function, and a floor heating function. Further, these functions can be attached separately when they are not incorporated in the water heater 32.

  Although the basic configuration of the cogeneration system of the present invention has been described above, a safety device and a control device are also incorporated. As a safety device sensor, first, in order to grasp the state of the fuel cell in the fuel cell 1, a voltage sensor 26 for monitoring the voltage is necessary. This voltage may be a cell or a stack in which a plurality of cells are bundled, a module in which each stack is bundled, or an arbitrary cell or a plurality of locations may be monitored in total. Furthermore, a combustion sensor 25 is also necessary to grasp the combustion state. This is because the off gas in the fuel cell is burned, and the combustion is sensed using the rectifying action of the flame.

  Furthermore, the temperature sensor 27 that senses the temperature is important. The temperature of the fuel cell module part, the temperature of the reforming part, the temperature of the combustion part, the temperature around the fuel cell 1 and the like are also detected. For detecting these temperatures, a thermocouple, a resistance temperature detector, a bimetal switch, a temperature fuse, or the like is used. The voltage sensor 26, the combustion sensor 25, and the temperature sensor 27 may be used not only as sensors for safety devices but also as control sensors or as data collection devices. .

A device for collecting data includes a device that senses current or power. As a result, it is possible to grasp the power generated by the fuel cell, the power used for the auxiliary machine, and the power used at home. Furthermore, data can be collected by a device that senses the amount of water used for hot water supply or senses the gas flow rate. Regarding the amount of gas used, a system that can collect data from a gas meter at home may be constructed without providing a sensor in the system.
The safety device may be provided with a gas sensor 33 in case the system is placed indoors or in case gas accumulates in the device. This gas sensor 33 can detect fuel gas leakage and incomplete combustion.

The control of the entire system may be performed in a centralized manner, or may be controlled using the arithmetic device of the inverter 21 or the arithmetic device of the water heater 32. A plurality of controls may be arranged, and the entire control may be performed by enabling communication between these controls.
The control can be performed by a remote control, and operation can be instructed from a home kitchen, a bath, etc., and the power generation amount and hot water storage amount can be displayed, and further instructions such as how to use electricity and hot water can be given. Furthermore, when equipped with an external communication function, various data such as control, power generation amount, hot water storage amount and usage amount can be remotely known by communication means such as a telephone line, LAN, optical fiber, and radio wave. .

  The home cogeneration system of the present invention has been described specifically for electricity and hot water, which are the basics of energy used at home, but can also be used in combination with various energy devices. For example, a heat source of an air conditioner such as a cooler or a fan heater, a power source, a heat source of a heat pump, or a power source. Furthermore, further improvement in power generation efficiency can be expected by combining generators such as gas turbines and gas engines. Furthermore, by combining with solar cells, it is possible to provide a household cogeneration system that does not require or requires a small amount of circulating fuel. In the daytime, household electricity is supplied by solar cells, and water is electrolyzed and stored, so that the electricity necessary for nighttime is generated by the fuel cell based on this water. Because it is possible to cover all of the above, it is possible to create an ultimate home power generation system that is friendly to the global environment.

(Embodiment)
Hereinafter, embodiments of the power generation / hot water supply cogeneration system of the present invention will be described.
FIG. 2 is a diagram showing an example in which the present invention is installed on a pipe shaft provided in a general apartment house. The pipe shaft 80 of the housing complex has a substantially rectangular parallelepiped shape, and includes a door and a space through which a gas meter, a water and sewage system, and a gas pipe pass. As shown in FIG. 2, in this embodiment, the cogeneration system of the present invention is divided into three of a power generation unit 40, a hot water heater (backup boiler) 50, and a hot water tank 60 and is arranged in the pipe shaft. . The power generation unit 40 and the water heater 50 are attached to the door 90 of the pipe shaft 80, and the hot water storage tank 60 is arranged in the space in parallel with the pipe 70 in the pipe shaft.

  By arranging in this way, the existing surplus space can be used effectively, so the adaptability to the place to be installed for home use is expanded. Furthermore, since the hot water tank 60 is installed independently, even when water leakage occurs, there is no influence on the supply unit of gas or the like and the electrical component of the power converter.

The hot water storage tank 60 is composed of two pipes having a substantially cylindrical shape whose axial direction is the vertical direction, and the upper and lower parts of the pipes are connected to each other by a pipe 61, so that the individual pipes communicate with each other at the upper and lower parts. And can be handled like a single tank. By doing in this way, it becomes possible to install a hot water storage tank using a narrow gap. In addition, the amount of hot water stored in the hot water tank can be flexibly handled by increasing or decreasing the number of pipes to be connected. Moreover, it is desirable that the hot water tank has a temperature gradient in the vertical direction in order to put hot water heated from above and take it out from below. For this purpose, a higher temperature gradient is ensured as the ratio between the height and the diameter of the pipe, that is, the aspect ratio is larger.
Furthermore, the hot water tank 60 is composed of a vacuum heat insulating pipe covered with a heat insulating material for heat insulation. By doing in this way, even if it installs multiple pipes as a hot water storage tank and a surface area increases, heat dissipation can be prevented by using a vacuum heat insulation pipe.

  FIG. 3 is a diagram showing an internal configuration of the power generation unit of the present invention. As shown in FIG. 3, the power generation unit 40 includes a module (fuel cell) 41 that houses solid oxide fuel cells in a container, and a supply unit 42 that supplies city gas, water, and air to the module 41. An exhaust heat recovery unit 43 that recovers exhaust heat from the exhaust gas, a power conditioner (power converter) 44 that converts electric power generated in the fuel cell into alternating current power, and connects to the power system, and water to be supplied And a pure water device 45 for replacing the water with pure water. The supply unit 42 includes a blower that supplies air, a flow meter that measures the flow rate, a tap water cutoff valve, a flow rate control device, a city gas cutoff valve, a flow rate control device, and the like. The exhaust heat recovery unit 43 includes a heat exchanger, a pump, and the like. The power conditioner 44 includes an ammeter, a battery, an inverter, and the like. The pure water device 45 includes a water purifier that purely changes water.

This power generation unit 40 is fixed to the door of the pipe shaft at the side part of the container, and has a lid that can be removed so that the inside of the power generation unit can be visually recognized at the front part. By having the lid, the lid can be removed and the inside of the power generation unit can be visually recognized without opening the door of the pipe shaft, and parts can be easily replaced during maintenance. Even if the inside of the power generation unit cannot be visually recognized from the outside of the pipe shaft, the power generation unit and the water heater can be provided on the inner side surface of the door.
In the above embodiment, the hot water storage tank 60 is composed of two substantially cylindrical pipes, and the upper parts and the lower parts of the pipes are connected to each other by a pipe 61. In the present invention, as shown in FIG. The hot water storage tank 75 may be configured by connecting the upper part of one pipe 75a and the lower part of the other pipe 75b by a pipe 75c. Further, the number of pipes is not limited to two and may be three or more. In such a hot water storage tank 75, hot water storage pipes 75a and 75b are connected in series, so that hot water and water are easily stored in a two-layered state (stratified state). Since it is easy to take out only the hot water from the hot water tank when necessary, a hot water tank having a relatively small capacity can be used efficiently.
FIG. 5 shows another embodiment of the present invention. In this power generation / hot water cogeneration system, a hot water storage tank storage container 77 for storing the hot water storage tank 76 is provided, and power generation is performed on the hot water storage tank storage container 77. A unit 40 is installed. As described above, the fuel cell 41, the supply unit 42, the exhaust heat recovery unit 43, the power conditioner (power converter) 44, and the pure water device 45 are accommodated in the container 40a of the power generation unit 40. ing.
The container 40 a is formed with an introduction hole 81 for taking in air from the outside, and the container 40 a and the hot water storage container 77 are each formed with a communication hole 83. In the lower part, a lead-out hole 85 for leading out air is formed. As the fan installed in the communication hole 83 rotates, air is introduced into the container 40 a from the introduction hole 81, and the heated air around the fuel cell 41 enters the hot water storage container 77 through the communication hole 83. Supplied and discharged from the outlet hole 85.
Further, pipes 76 a and 76 b constituting the hot water storage tank 76 are accommodated in the hot water storage container 77, and the upper and lower surfaces of these pipes 76 a and 76 b contact the upper and lower inner wall surfaces of the hot water storage container 77. In contact therewith, the power generation unit 40 installed on the hot water storage container 77 is supported.
In such a power generation / hot water cogeneration system, the hot water storage container 77 for storing the hot water storage tank 76 also serves as a frame, and the power generation unit 40 is installed on the storage tank 77, so that it exists between the power generation unit 40 and the hot water storage tank 76. Piping for hot water recovery can be minimized.
Further, the heated air in the power generation unit 40 can be introduced into the hot water storage tank storage container 77, and the heat dissipation loss in the hot water storage tank 76 can be reduced.
Furthermore, the hot water tank 76 itself can be provided with the strength to receive the weight of the power generation unit 40, and it is not necessary to provide a strong frame in the hot water tank storage container 77, and an inexpensive and small system can be provided.

It is a schematic block diagram which shows the electric power generation / hot-water supply cogeneration system which is an example of this invention. It is a figure which shows the example which installed this invention in the pipe shaft with which a general apartment house is equipped. It is a figure which shows the structure inside the electric power generation unit of this invention. It is a figure which shows the state which connected the upper part of one pipe, and the lower part of the other pipe by piping. It is a figure which shows the other form of this invention.

Explanation of symbols

1 Fuel cell 30, 60 Hot water storage tank 32, 50 Water heater 40 Power generation unit 41 Module (fuel cell)
61 Junction (joint part)
70 Piping pipe 40a Container 75, 76 Hot water storage tank 75a, 75b, 76a, 76b Pipe 75c Piping 77 Hot water storage container

Claims (9)

At least a power generation unit containing a solid oxide fuel cell in a container;
A hot water storage tank comprising a plurality of pipes to the vertical direction accumulated and axial hot water heated by exhaust heat recovery of the power generation unit,
A hot water heater for replenishing hot water when the hot water in the hot water tank is insufficient,
The power generation / hot water cogeneration system, wherein the hot water storage tank and the water heater are separately installed.   The power generation unit includes a supply means for supplying fuel gas, an oxygen-containing gas and water to the fuel cell, an exhaust heat recovery means for recovering exhaust heat exhausted from the fuel cell, and an AC power generated by the fuel cell. The power generation / hot water cogeneration system according to claim 1, wherein the container includes power conversion means that converts the power into power and connects the power to the power system. 3. The power generation / hot water cogeneration system according to claim 1, wherein in the hot water storage tank, upper portions and lower portions of the pipes are connected by piping. 3. The power generation / hot water cogeneration system according to claim 1, wherein an upper part of the one pipe and a lower part of the other pipe are connected by piping in the hot water storage tank. The power generation / hot water cogeneration system according to any one of claims 1 to 4 , wherein the hot water storage tank comprises a vacuum heat insulating pipe. The power generation / hot water cogeneration system according to any one of claims 1 to 5 , wherein the container has a front part having a removable lid and a side part that can be fixed. The power generation unit according to any one of claims 1 to 6 , further comprising a hot water tank storage container in which the hot water storage tank is stored, and wherein the power generation unit is installed on the hot water storage tank storage container. Hot water cogeneration system. The power generation / hot water cogeneration system according to claim 7 , further comprising air introduction means for introducing air around the fuel cell into the hot water tank storage container. The power generation / hot water cogeneration system according to claim 7 or 8 , wherein the hot water storage tank supports an upper surface in the hot water storage tank storage container.

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