JP2002081743A - Waste heat utilizing system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a waste heat utilizing system of a cogeneration apparatus. SOLUTION: There are provided a cogeneration apparatus, a plurality of waste heat utilizing apparatuses for utilizing waste heat from the cogeneration apparatus, and waste heat distribution means for distributing waste heat from the cogeneration apparatus. The cogeneration apparatus is applicable to any of a solid high polymer type fuel cell or a micro gas turbine heat-combined supply apparatus or a gas engine heat-combined supply apparatus. The waste heat utilizing apparatus is at least two or more of a water heater, a heating apparatus, a cooling apparatus, a dehumidifying apparatus, and a heat storage apparatus.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a waste heat utilization system utilizing waste heat from a cogeneration unit. In particular, the present invention relates to a technique for effectively utilizing waste heat of a cogeneration system in a field where heat demand fluctuates in a consumer field such as a home.

[0002]

2. Description of the Related Art A fuel cell is known as a cogeneration system using a clean fuel such as hydrogen. Fuel cells are roughly classified according to the type of electrolyte that transfers ions between the anode and the cathode. The operating temperature of a solid oxide fuel cell is about 1
000 ° C., the operating temperature of the molten carbonate fuel cell is about 650
C., the operating temperature of the phosphoric acid type fuel cell is about 200 ° C., and the operating temperature of the polymer electrolyte fuel cell is about 80 ° C.

[0003] The operating temperature of a polymer electrolyte fuel cell is about 80 ° C as described above, and the exhaust heat recovered therefrom is ideally 80 ° C, but is actually 80 ° C or less due to heat dissipation loss. .

In recent years, a cogeneration system using a micro gas turbine or a small gas engine has been developed. The operating temperature of these internal combustion engines is several hundred degrees Celsius, but for cooling turbines and engines, heat is exchanged by circulating cooling water through cooling jackets and generally recovering exhaust heat as hot water of about 80 to 90 ° C. Have been.

As described above, the waste heat of these cogeneration devices is often recovered and used as hot water, and is expected to be widely used in the household and other household fields in the future.

As a system utilizing the exhaust heat of a polymer electrolyte fuel cell, there is a system disclosed in Japanese Patent Application Laid-Open No. Hei 10-311564. This system sends the exhaust gas from the cathode of the fuel cell, the exhaust heat of the cell body and the reformer to the heat exchanger for indoor air conditioning, and heats the outside air with this heat exchanger to perform heating. . Further, instead of heating the outside air, as shown in FIG. 2, a system is also known in which waste water from the fuel cell 1 is used to heat clean water by a heat exchanger 31 to make hot water.

[0007]

However, in the prior art, since the waste heat from a cogeneration unit such as a polymer electrolyte fuel cell is a single use of heat, for example, the above-mentioned Japanese Patent Application Laid-Open No. H10-311564 is disclosed. In the system disclosed in the gazette, there is a serious problem that waste heat is excessive in summer when heating is not required, and the waste heat utilization efficiency is reduced. In such a case, since cooling by exhaust heat recovery is not performed in the combined heat and power supply device, the operating temperature may increase and stable operation may not be performed. In order to avoid this, it is necessary to install a device for discharging exhaust heat to the atmosphere, which has led to an increase in cost and complexity of the device.

In a cogeneration system such as a polymer electrolyte fuel cell, it is important to use waste heat with high efficiency, and it is possible to flexibly cope with seasonal fluctuations in heat demand or temporal fluctuations in a day. There is a demand for the development of technology that can utilize the data without waste.

The present invention has been made in view of the above-described problems of the related art, and has as its object to provide a waste heat utilization system that can effectively utilize waste heat from a cogeneration unit.

[0010]

In order to solve the above-mentioned problems of the prior art,

According to a first aspect of the present invention, there is provided a waste heat utilization system, comprising: a combined heat and power supply device; a plurality of waste heat utilization devices utilizing waste heat from the combined heat and power supply device; and a waste heat distributing waste heat from the combined heat and power supply device. Heat distributing means.

[0012] A waste heat utilization system according to a second invention is characterized in that the cogeneration unit is a polymer electrolyte fuel cell having an anode and a cathode.

[0013] A waste heat utilization system according to a third invention is characterized in that the cogeneration system is a micro gas turbine type cogeneration system.

[0014] A waste heat utilization system according to a fourth aspect of the present invention is characterized in that the cogeneration system is a gas engine cogeneration system.

The exhaust heat utilization system according to a fifth aspect is characterized in that the exhaust heat distribution means is controlled by a state quantity detecting means and a controller which processes a signal from the state quantity detecting means.

Here, the state quantity detecting means includes an operating state (temperature, humidity, generated voltage, generated current, pressure, etc.) of the cogeneration system, an operating state (temperature, humidity, pressure, etc.) of the waste heat utilization device, and a discharge state. It refers to detection means such as a temperature sensor, a humidity sensor, a voltage sensor, a current sensor, and a pressure sensor for detecting the state (temperature, humidity, pressure, etc.) of the environment in which the heat utilization device is installed. The exhaust heat distribution means can be appropriately controlled based on the state quantities detected by these state quantity detection means.

The exhaust heat utilization system according to a sixth invention is characterized in that the exhaust heat utilization device is a combination of at least two of a hot water supply device, a heating device, a cooling device, a dehumidifying device, and a heat storage device.

The exhaust heat utilization system according to a seventh aspect is characterized in that the cooling device is an open cycle type adsorption / dehumidification cooling device.

An exhaust heat utilization system according to an eighth aspect is characterized in that the dehumidifier is an adsorption dehumidifier.

[0020]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is an example of a configuration diagram of an exhaust heat utilization system according to the present invention, which includes a polymer electrolyte fuel cell 1, a hot water supply device 5, a heating device 6, an open cycle adsorption / dehumidification / cooling device 7, an exhaust heat distributor 4, The exhaust heat distribution controller 41 is configured in combination.

The polymer electrolyte fuel cell 1 includes an anode (a fuel electrode, a negative electrode), a cathode (an air electrode, a positive electrode), a polymer membrane that allows passage of hydrogen ions (H ⁺ ) but does not allow electrons, and a cooling unit. Is configured. FIG. 1 does not show the internal configuration of the polymer electrolyte fuel cell 1. Pure hydrogen gas or hydrogen-rich fuel gas is used as the fuel supplied to the anode. Generally, a hydrogen-rich gas obtained by converting a raw fuel such as city gas, propane gas, gasoline, or methanol by the fuel processor 2 is used.

The hydrogen gas supplied to the anode is separated into electrons (e ⁻ ) and hydrogen ions (H ⁺ ) by the action of a catalyst on the surface of the polymer film, and only hydrogen ions (H ⁺ ) pass through the polymer film. To the cathode, and the electrons (e ⁻ ) reach the cathode via the conductor, and perform electrical work during this time. The hydrogen ions (H ⁺ ) reaching the cathode react with oxygen (O ₂ ) in the air supplied to the cathode to become water (H ₂ O), and the gas containing the water (H ₂ O) is discharged into the exhaust air. Is discharged from the cathode. The fuel gas supplied to the anode is
It is discharged after being used for the power generation reaction, but is sent to the fuel processor 2 because it contains residual hydrogen in the fuel exhaust gas, and is used as a fuel for heating a reformer or the like. Here, the operating temperature of the polymer electrolyte fuel cell is about 80 ° C., and the exhaust heat obtained therefrom is 80 ° C. or less, and is about 60 ° C. depending on conditions such as heat dissipation loss.

The hot water supply device 5 is a device for supplying hot water by heating tap water by exhaust heat discharged from the polymer electrolyte fuel cell 1.

The heating device 6 is a device that raises the temperature of the air by the exhaust heat exhausted from the polymer electrolyte fuel cell 1 and supplies it to the room as warm air.

FIG. 3 shows an example of the open cycle type adsorption / dehumidification / cooling apparatus 7. It is basically composed of a dehumidifier 12, a heater 16, a sensible heat exchanger 13, and an evaporative cooler. The dehumidifier 12 removes moisture in the outside air, and the air from which the moisture has been removed is used as a sensible heat exchanger. The heat is exchanged at 13 and cooled, and the air cooled to a certain extent is further cooled by an evaporative cooler and supplied to the room, while the warmed air in the room is cooled by the evaporative cooler and then cooled. The sensible heat exchanger 13 is sent to the heat exchanger 13 to cool the sensible heat exchanger 13 and then heated by the heater 16 to a temperature at which the adsorbent of the dehumidifier 12 can be regenerated. Regenerate and be released outside. Further, the evaporative cooler may not be provided particularly in a cold region. FIG. 3 shows an example in which the low-temperature exhaust heat from the polymer electrolyte fuel cell 1 is used for the regeneration heat of the adsorbent of the open-cycle adsorption / dehumidification / cooling apparatus 7, and the exhaust heat is also used in this embodiment. I do.

The exhaust heat distributor 4 distributes the exhaust heat discharged from the polymer electrolyte fuel cell to an exhaust heat utilization device utilizing the exhaust heat in accordance with the heat demand. Can be constituted by the combination of the solenoid valves.

The exhaust heat distribution controller 41 has a function of controlling the exhaust heat distributor so as to optimize the distribution of the exhaust heat to the exhaust heat utilization device based on the indoor and / or outdoor state quantity. In FIG. 1, which is the present embodiment, the state quantities are temperature and humidity, and the temperature sensor 42 and the humidity sensor 4
3 is detected.

In a general living space, heat demands such as cooling, heating, hot water supply and the like fluctuate seasonally or chronologically in one day. In this embodiment, an open cycle type adsorption / dehumidification / cooling device 7 which can be driven by exhaust heat of 80 ° C. or less from a polymer electrolyte fuel cell is combined with a hot water supply device 5 and a heating device 6, and further, these exhaust heat utilization devices are used. In the distribution of the exhaust heat, the exhaust heat distributor 4 is controlled by the exhaust heat distribution controller 41 that processes signals from the temperature sensor 42 and the humidity sensor 43 that detect the temperature and humidity inside and outside the room, and can cope with fluctuations in heat demand. I did it.

For example, when the temperature is high in the summer, the demand for the cold heat can be met by increasing the distribution of the exhaust heat to the open-cycle adsorption / dehumidification / cooling apparatus 7. When the temperature is low in winter, the exhaust heat is
By increasing the allocation to the heat, it is possible to respond to the heat demand.

The hot water obtained by distributing the exhaust heat to the hot water supply device 5 is desirably provided with a hot water storage tank in order to accommodate hot water supply during a time when hot water supply demand increases.

Examples of the use of exhaust heat other than the present embodiment include, in the case of high humidity, a method of performing dehumidification by increasing the distribution of exhaust heat as an adsorbent regeneration heat source of the adsorption and dehumidification device to the adsorption and dehumidification device; When the heat is small, there is a method of distributing the waste heat to the heat storage device and storing the waste heat, and using the heat storage during the time when the heat demand is large. Can be. In addition, it is desirable that the exhaust heat utilization device is a combination of the exhaust heat utilization devices that enhances the thermal efficiency as a whole in consideration of the difference in heat demand due to regional characteristics and the like.

In the above-described embodiment, an example of utilizing the exhaust heat of the polymer electrolyte fuel cell as the cogeneration system has been described, but the exhaust heat from other cogeneration systems such as a micro gas turbine and a gas engine may also be used. It can be used as well.

[0033]

As described above, in the exhaust heat utilization systems according to the first to fourth inventions, since a plurality of exhaust heat utilization devices and exhaust heat distributors are provided, the heat and power supply devices can be reduced. Waste heat utilization method can be selectively used.

The system according to the fifth aspect of the present invention includes a state quantity detecting means and a controller, and can control fluctuations in heat demand by controlling the amount of exhaust heat distribution based on the state quantity.

In the system according to the sixth aspect, the exhaust heat utilization device is a combination of at least two of a hot water supply device, a heating device, a cooling device, a dehumidifying device, and a heat storage device. The waste heat can be used according to the change over time.

[0036] In the system according to the seventh aspect of the invention, the cooling device is an open-cycle adsorption dehumidifying cooling device,
Cold heat can be used even with low-temperature exhaust heat.

In the system according to the eighth aspect of the present invention, since the dehumidifying device is an adsorption dehumidifying device, dehumidification can be performed using low-temperature exhaust heat as regeneration heat of the dehumidifying agent.

In particular, in a cogeneration system for a living space in which the seasonal and temporal fluctuations in heat demand such as heating, hot water supply, and cooling are large, the method of utilizing the exhaust heat is a major problem. It is possible to use waste heat without waste corresponding to the fluctuation.

[Brief description of the drawings]

FIG. 1 is an example of an overall configuration diagram of a solid polymer fuel cell exhaust heat utilization system according to the present invention.

FIG. 2 is an example of an overall configuration diagram of a conventional polymer electrolyte fuel cell system using exhaust heat of a fuel cell.

FIG. 3 is an example of an overall configuration diagram of a polymer electrolyte fuel cell system in which exhaust heat of a fuel cell is used in an open cycle adsorption / dehumidification / cooling apparatus.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 solid polymer fuel cell 2 fuel processor 4 exhaust heat distributor 5 hot water supply device 6 heating device 7 open cycle adsorption dehumidifying and cooling device 10 heat storage device 12 rotary dehumidifier 13 rotary sensible heat exchanger 16 exhaust heat heater 31 heat exchanger 41 exhaust heat distribution controller 42 temperature sensor 43 humidity sensor

 ──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Hirofumi Sato 2-1-1 Nakajima, Kokurakita-ku, Kitakyushu-shi, Fukuoka F-term (reference) 5H026 AA06

Claims (8)

[Claims] 1. A heat and power supply apparatus, comprising: a plurality of waste heat utilization apparatuses utilizing waste heat from the heat and power supply apparatus; and exhaust heat distribution means for distributing waste heat from the heat and power supply apparatus. Characteristic waste heat utilization system. 2. The exhaust heat utilization system according to claim 1, wherein said cogeneration system is a polymer electrolyte fuel cell having an anode and a cathode. 3. The exhaust heat utilization system according to claim 1, wherein said cogeneration system is a micro gas turbine type cogeneration system. 4. The exhaust heat utilization system according to claim 1, wherein said cogeneration system is a gas engine type cogeneration system. 5. The apparatus according to claim 1, wherein said exhaust heat distribution means is controlled by a state quantity detecting means and a controller which processes a signal from said state quantity detecting means. Waste heat utilization system. 6. The apparatus according to claim 1, wherein the exhaust heat utilization device is a combination of at least two of a hot water supply device, a heating device, a cooling device, a dehumidifying device, and a heat storage device. Exhaust heat utilization system as described. 7. The exhaust heat utilization system according to claim 6, wherein said cooling device is an open cycle adsorption / dehumidification cooling device. 8. The system according to claim 6, wherein said dehumidifying device is an adsorption dehumidifying device.