JP2003056909A - Heat recovery apparatus and cogeneration system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high reliability heat recovery apparatus and cogeneration system without causing the possibility of the propagation of Legionella. SOLUTION: A heat recovery apparatus is adapted such that a hot medium heated with heat produced by a fuel cell 1 is circulated, whereby the heat recovered from the fuel cell 1 is dissipated in a heat exchanger 6 to heat water in a hot water storage tank 5 for heat storage. In the apparatus, an electric heater 3 is provided for heating the hot medium, with which heater 3 the heat medium is heated with the aid of surplus electric power of the fuel cell 1 or electric power of a commercial power supply 15 to bring the temperature of warm water in the hot water storage tank 5 to 80 deg.C or higher for sterilization processing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat recovery device for recovering heat generated by a heat source having a power generation function such as a fuel cell and a cogeneration system including the heat recovery device, and more particularly to a heat recovery device including a hot water storage tank. And the cogeneration system.

[0002]

2. Description of the Related Art As a conventional heat recovery device, for example, a heat exchanger in which a heat medium heated by exhaust heat from a heat source such as a fuel cell is supplied and circulated is installed in a hot water storage tank as a heat storage tank. There is one that heats the low-temperature water to store heat by heat exchange between the heat medium and the low-temperature water in the hot-water storage tank by the heat exchanger, and supplies the stored hot water as needed.

[0003]

In such a heat recovery device, when the heat source is, for example, a polymer electrolyte fuel cell, the temperature of the exhaust heat is low, so that it is stored in the hot water storage tank. The temperature of the hot water thus obtained does not reach about 60 ° C. to 70 ° C., which is an effective temperature for sterilizing Legionella bacteria, etc., and Legionella bacteria etc. may propagate in the hot water storage tank.

The present invention has been made in view of the above points, and it is an object of the present invention to provide a highly reliable heat recovery device and a cogeneration system that are free from the risk of breeding Legionella bacteria and the like. And

[0005]

In order to achieve the above-mentioned object, the present invention is constructed as follows.

That is, the heat recovery device of the present invention according to claim 1 is a heat exchanger for heating water in a heat storage tank to store heat by a heat exchanger in which a heat medium heated by heat generated by a heat source having a power generation function flows. In the recovery device, the temperature of the heat medium heated by the heat generated by the heat source is equal to or lower than a required temperature, and a sterilizing means for sterilizing water in the heat storage tank is provided, and the sterilizing means is power generated by the heat source. And, at least one of the electric power of the commercial power supply is supplied and driven.

Here, the required temperature means the water in the heat storage tank,
It refers to the temperature of the heat medium that can be heated to the temperature required to sterilize Legionella bacteria.

According to the first aspect of the present invention, since the sterilizing means driven by being supplied with at least one of the electric power generated by the heat source and the electric power from the commercial power source is provided, the heat generated by the heat of the heat source is used. Even if the temperature of the medium is below the required temperature and the temperature of the hot water in the heat storage tank does not reach the temperature required for sterilization, the sterilizing means can be driven to sterilize the water in the heat storage tank. Can be prevented from breeding.

According to a second aspect of the present invention, in the first aspect of the present invention, the heat source is a fuel cell and supplies electric power to a load, and the sterilizing means has power generated by the heat source. Is supplied and driven with surplus power exceeding the power consumption of the load.

According to the present invention of claim 2, the electric power generated by the fuel cell for supplying electric power to a load such as a domestic load is
Since the sterilization means is driven by using the surplus power exceeding the power consumption of the load to perform the sterilization, the energy can be efficiently used.

According to a third aspect of the present invention, in the invention of the first or second aspect, the heat source is a fuel cell and supplies electric power to a load, and the sterilizing means is periodically provided with the sterilizing means. It is driven by being supplied with electric power.

According to the third aspect of the present invention, since the sterilizing means is regularly supplied with electric power to perform the sterilizing treatment, the sterilizing treatment is regularly performed at a frequency capable of preventing the propagation of Legionella bacteria and the like. Therefore, the amount of electric power required for sterilization can be suppressed.

According to a fourth aspect of the present invention, in the invention according to any one of the first to third aspects, the sterilizing means includes at least one of an electric heater and an ultraviolet ray irradiating means, and the electric heater is provided in the heat storage tank. Of at least one of the water and the heating medium to bring the temperature of the water in the heat storage tank to a predetermined temperature or higher, and the ultraviolet irradiation means irradiates the water in the heat storage tank with ultraviolet rays. is there.

Here, the predetermined temperature refers to a temperature at which Legionella bacteria and the like can be sterilized.

According to the fourth aspect of the present invention, the temperature of the water in the heat storage tank is raised to a predetermined temperature or higher by the electric heater, or the water in the heat storage tank is irradiated with ultraviolet rays by the ultraviolet irradiation means, whereby Legionella bacteria Can be sterilized.

A cogeneration system of the present invention according to claim 5 comprises the heat recovery device according to any one of claims 1 to 4, and a solid polymer fuel cell as the heat source having a power generation function. There is.

According to the present invention of claim 5, since the temperature of the exhaust heat is low, the temperature of the hot water stored in the heat storage tank is about 60 ° C. In the system, water in the heat storage tank can be sterilized to prevent Legionella bacteria and the like from propagating in the heat storage tank.

[0018]

DETAILED DESCRIPTION OF THE INVENTION The details of the present invention will be described below with reference to the embodiments shown in the drawings.

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

In this embodiment, the electricity generated by the fuel cell 1 as a heat source having a power generation function is converted into electricity as a domestic load 2 of a general household in which the cogeneration system is installed and a sterilizing means described later. This is a fuel cell cogeneration system that supplies hot water to the heater 3 while collecting exhaust heat from the fuel cell 1.

In the figure, reference numeral 4 denotes an exhaust heat recovery circuit for circulating exhaust heat from the fuel cell 1, for example, a heat medium such as an antifreeze solution heated by exhaust heat from a reformer or a cell of the fuel cell. A heat exchanger 6 installed inside a hot water storage tank 5 as a tank, a circulation pump 7, and the electric heater 3 are provided.

At the lower water supply port of the hot water storage tank 5, a water supply pipe 8 is provided.
On the other hand, a hot water outlet pipe 9 is connected to the hot water outlet at the top, and the mixing valve 10 mixes the hot water from the hot water tank 5 with the hot water from the hot water supply pipe 8 and the hot water from the hot water heater 11. It is designed to be supplied with hot water.

In this system, the fuel cell 1 is operated and the circulation pump 7 of the exhaust heat recovery circuit 4 is driven to transfer the heat medium from the fuel cell 1 through the heat exchanger 6 as indicated by the arrow. The waste heat recovered from the fuel cell 1 is radiated by the heat exchanger 6 to circulate and circulate the low temperature water in the hot water storage tank 5 to store the heat, and the hot water stored in the hot water storage tank 5 is stored. However, if necessary, the mixing valve 10 and the water heater 1
Water is supplied to the hot water storage tank 5 from the water supply pipe 8 while hot water is supplied via the water supply pipe 1.

The fuel cell 1 of this embodiment is a polymer electrolyte fuel cell, and the temperature of the heat medium flowing from the fuel cell 1 to the hot water storage tank 5 is, for example, about 60 ° C.
The temperature of the heat medium returning from the fuel cell 1 to the fuel cell 1 is, for example, about 50 ° C.

The water heater 11 has a hot water heat exchanger 12 therein, and heats the hot water from the mixing valve 10 to a set hot water temperature when the temperature of the hot water from the hot water storage tank 5 is low. To hot water.

Reference numeral 13 controls the operation stop of the fuel cell 1 and controls each part in accordance with the output of various sensors such as the thermistor 20 for detecting the temperature of the water in the hot water storage tank 5 and the setting operation of a remote controller (not shown). The controller 13, which is a controller, controls a reverse flow prevention circuit 14 that prevents reverse flow from the fuel cell 1 to the grid and supplies electric power to the electric heater 3 as described later.

The fuel cell 1 is a polymer electrolyte fuel cell as described above, and since the temperature of its exhaust heat is low, the temperature of the hot water stored in the hot water storage tank 5 is also effective for sterilizing Legionella bacteria. It does not reach the temperature of about 60 ° C to 70 ° C.

Therefore, in this embodiment, in order to prevent Legionella bacteria and the like from propagating in the hot water storage tank 5, the exhaust heat recovery circuit 4 is provided with the electric heater 3 as described above. The electric heater 3 heats a heat medium, and the temperature of the hot water in the hot water storage tank 5 heated by the heat medium, that is, the temperature detected by the thermistor 20 is set to 80 ° C. or higher for sterilization. I have to.

In general, Legionella bacteria are 60 ° C to 70 ° C.
It is said that the sterilization treatment of several tens of seconds is sufficient for killing. In this embodiment, the temperature is heated to 80 ° C. or higher with a margin, and the time required to rise from 70 ° C. to 80 ° C. is sufficient for sterilization. Since it is possible, the heating is stopped when the temperature reaches 80 ° C. The heating temperature is not limited to 80 ° C and may be any temperature as long as it can sterilize Legionella bacteria and the like.

The sterilization process by the electric heater 3 is carried out by the surplus power given through the reverse current prevention circuit 14 when the power generated by the fuel cell 1 exceeds the power consumed by the domestic load 2. .

That is, assuming that the power generation output of the fuel cell 1 is, for example, 1 kW, the amount of electric power used at home is 1
When the temperature falls below KW, the surplus electric power is used to heat the heating medium by the electric heater 3 to heat the hot water in the hot water storage tank 5 to 80%.
It is a sterilization treatment by heating above ℃.

When the temperature of the hot water in the hot water storage tank 5 cannot be heated to 80 ° C. only with the surplus power, the controller 13
Controls the reverse tide prevention circuit 14 to supply electric power from the commercial power supply 15 to the electric heater 3 to heat the hot water in the hot water storage tank 5 to 80 ° C. or higher.

As described above, the surplus power can be effectively used to sterilize the water in the hot water storage tank 5 to prevent the propagation of Legionella bacteria or the like.

The power consumption of the domestic load 2 is small,
When surplus power is frequently generated, it is conceivable to stop the operation of the fuel cell 1 and cover it with the commercial power supply 15. In such a case, however, the fuel cell 1 is operated every time surplus power is generated. It is wasteful to heat the heating medium with the electric heater 3 without stopping.

That is, when the heat medium from the fuel cell 1 is heated and sterilized by the electric heater 3, the return temperature of the heat medium to the fuel cell 1 also becomes high, so that the fuel cell 1
On the side, a radiator built in the fuel cell 1 (not shown) needs to dissipate heat by itself so as not to overheat, but energy is wasted by the self-dissipating heat.

Therefore, when the operation of the fuel cell 1 can be stopped, the sterilization process is not performed when the surplus power is generated, but the controller is regularly operated, for example, about once a month. The reverse tide prevention circuit 14 may be controlled by 13 to supply electric power from the commercial power supply 15 to the electric heater 3 to perform the sterilization process. As a result, it is possible to suppress waste due to self-radiation of the radiator.
This periodic sterilization process may be performed only with the power of the commercial power source 15, or may be used together with the surplus power.

On the other hand, once the fuel cell 1 is stopped, it takes several hours to start it up. Therefore, when the power consumption of the domestic load is large, the fuel cell 1 is always operated without being stopped. Preferably. In this way, when the operation of the fuel cell 1 is not stopped, even if the sterilization process is not performed, the radiator heats itself so that the return temperature of the heat medium to the fuel cell 1 does not become too high. It is preferable to perform sterilization treatment by the electric heater 3 using electric power.

(Embodiment 2) FIG. 2 is a schematic configuration diagram of a cogeneration system according to another embodiment of the present invention, in which portions corresponding to those in Embodiment 1 described above are designated by the same reference numerals. Attach.

In the above-described embodiment, the heat medium from the fuel cell 1 is heated to sterilize the hot water in the hot water storage tank 5 to a temperature of 80 ° C. or higher, while in the present embodiment, the hot water storage tank is sterilized. An electric heater 16 as a sterilizing means is provided in the unit 5.

The sterilization by the electric heater 16 may be performed by surplus power in which the generated power of the fuel cell 1 exceeds the power consumption of the domestic load 2, as in the above-described embodiment. If the temperature of the hot water in the hot water storage tank 5 cannot be raised to 80 ° C or higher by itself, the commercial power supply 15
May be supplied. Alternatively, the electric heater 16 may be supplied with electric power periodically, for example, about once a month.

In this embodiment, the water in the hot water storage tank 5 can be heated directly to 80 ° C. or higher for sterilization.

Other configurations and effects are similar to those of the above-described first embodiment.

(Embodiment 3) FIG. 3 is a schematic configuration diagram of a cogeneration system according to still another embodiment of the present invention, in which parts corresponding to those in the above-mentioned Embodiment 1 are referred to by the same reference numerals. Add a sign.

In each of the above embodiments, the electric heater 3,
While the temperature of the hot water in the hot water storage tank 5 is set to a high temperature of 80 ° C. or higher for sterilization by means of 16, the ultraviolet lamp 17 is provided in the hot water storage tank 5 in this embodiment, and The warm water is irradiated with ultraviolet rays and sterilized.

The sterilization by the ultraviolet lamp 17 may be performed by surplus power in which the generated power of the fuel cell 1 exceeds the power consumption of the domestic load 2, as in the above-mentioned embodiment. Then, when sufficient sterilization cannot be performed, electric power of the commercial power supply 15 may be supplied. Alternatively, for example, the sterilization by ultraviolet irradiation may be performed once a month for a predetermined time about once a month.

In this embodiment, the water in the hot water storage tank can be irradiated with ultraviolet rays to sterilize Legionella bacteria and the like to prevent their reproduction.

(Other Embodiments) In the present invention, each of the above-described embodiments may be appropriately combined. For example, by combining the first embodiment and the second embodiment to heat the heating medium, The hot water in the hot water storage tank 5 may be heated, or by combining the first embodiment and the third embodiment to heat the heating medium and irradiate the hot water in the hot water storage tank with ultraviolet rays. Good.

In each of the above-described embodiments, the heat medium heated by the exhaust heat of the fuel cell 1 is circulated through the heat exchanger 6 arranged in the hot water storage tank 5 to store the heat in the hot water storage tank 5. However, as another embodiment of the present invention, for example, as shown in FIG. 4, a heat exchange in which a heat medium that exchanges heat with steam circulates in a discharge path 30 of steam from the cooling system of the fuel cell 1. It is also possible to provide the vessel 31 and circulate the heat medium heated by steam through the heat exchanger 6 in the hot water storage tank 5 to store heat in the hot water storage tank 5. In this case, the electric heater 3 is provided in the circulation path of the heating medium heated by steam.

Alternatively, as shown in FIG. 5, the first exhaust heat recovery circuit 4a in which the first heat medium heated by the exhaust heat of the fuel cell 1 circulates and the heat placed in the hot water storage tank 5 Exchanger 6
A second exhaust heat recovery circuit 4b in which the second heat medium circulates via
A heat exchanger 33 is provided between the heat exchanger 33 and the heat exchanger 33, the second heat medium is heated by the first heat medium in the heat exchanger 33, and the heated second heat medium is arranged in the hot water storage tank 5. The heat may be stored in the hot water storage tank 5 by being circulated through the heat exchanger 6. In this case, the electric heater 3 may be provided on at least one of the path through which the first heat medium circulates and the path through which the second heat medium circulates. Note that 7a and 7b are circulation pumps.

Further, in each of the above-described embodiments, the heat medium heated by the exhaust heat of the fuel cell 1 is circulated through the heat exchanger 6 arranged in the hot water storage tank 5 to remove the water in the hot water storage tank 5. Although heated and stored, as another embodiment of the present invention, as shown in FIGS. 6 and 7 corresponding to FIGS. 4 and 5 described above, for example, a heat exchanger 6 is provided in the hot water tank 5. Instead of providing
The water in the hot water storage tank 5 is circulated by the circulation pumps 7 and 7b, and in the heat exchangers 31 and 33 provided in the circulation paths, the water is heated by the heat medium heated by the exhaust heat of the fuel cell 1. You may make it store heat.

[0051]

As described above, according to the present invention, since the sterilizing means that is driven by being supplied with at least one of the generated power of the heat source and the power of the commercial power source is provided, the heat generated by the heat of the heat source is used. The temperature of the medium is below the required temperature,
Even if the temperature of the hot water in the heat storage tank does not reach the temperature required for sterilization, the sterilizing means can be driven to sterilize the water in the heat storage tank, and the propagation of Legionella bacteria can be prevented.

Further, since the sterilization means is driven by using the surplus electric power of the heat source for supplying the electric power to the domestic load, the sterilization can be performed efficiently.

Further, since the sterilizing means is supplied with electric power to perform sterilization on a regular basis, it is possible to suppress electric power required for sterilization by performing regular sterilization at a frequency that can prevent propagation of Legionella bacteria and the like. Become.

According to the present invention, in a cogeneration system using a polymer electrolyte fuel cell having a low exhaust heat temperature, water in the heat storage tank is sterilized and Legionella bacteria and the like propagate in the heat storage tank. Can be prevented.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a cogeneration system according to a first embodiment of the present invention.

FIG. 2 is a schematic configuration diagram of a cogeneration system according to a second embodiment of the present invention.

FIG. 3 is a schematic configuration diagram of a cogeneration system according to a third embodiment of the present invention.

FIG. 4 is a schematic configuration diagram of a cogeneration system according to another embodiment of the present invention.

FIG. 5 is a schematic configuration diagram of a cogeneration system according to still another embodiment of the present invention.

FIG. 6 is a schematic configuration diagram of a cogeneration system according to another embodiment of the present invention.

FIG. 7 is a schematic configuration diagram of a cogeneration system according to still another embodiment of the present invention.

[Explanation of symbols]

1 fuel cell 2 domestic load 3,16 Electric heater 4 Exhaust heat recovery circuit 5 hot water storage tank 6 heat exchanger 15 Commercial power supply 17 UV lamp

   ─────────────────────────────────────────────────── ─── Continued front page    (71) Applicant 000221834             Toho Gas Co., Ltd.             19-18 Sakurada-cho, Atsuta-ku, Nagoya-shi, Aichi (71) Applicant 000196680             Seibu Gas Co., Ltd.             1-1-17 Chiyo, Hakata-ku, Fukuoka City, Fukuoka Prefecture (72) Inventor Tatsuro Arai             93 Edo-cho, Chuo-ku, Kobe-shi, Hyogo Stock Association             Company Noritsu (72) Inventor Takuji Saeki             93 Edo-cho, Chuo-ku, Kobe-shi, Hyogo Stock Association             Company Noritsu (72) Inventor, T. Suzuki             1-5-20 Kaigan, Minato-ku, Tokyo Tokyo Gas             Within the corporation (72) Inventor Kenichi Tanogami             1-5-20 Kaigan, Minato-ku, Tokyo Tokyo Gas             Within the corporation (72) Inventor Kazuya Yamaguchi             1-5-20 Kaigan, Minato-ku, Tokyo Tokyo Gas             Within the corporation (72) Inventor Yoshitaka Kasahara             4-1-2 Hirano-cho, Chuo-ku, Osaka-shi, Osaka Prefecture               Within Osaka Gas Co., Ltd. (72) Inventor Shin Iwata             4-1-2 Hirano-cho, Chuo-ku, Osaka-shi, Osaka Prefecture               Within Osaka Gas Co., Ltd. (72) Inventor Keiji Takimoto             4-1-2 Hirano-cho, Chuo-ku, Osaka-shi, Osaka Prefecture               Within Osaka Gas Co., Ltd. (72) Inventor Tadao Sugawara             4-1-2 Hirano-cho, Chuo-ku, Osaka-shi, Osaka Prefecture               Within Osaka Gas Co., Ltd. (72) Inventor Hiroshi Takagi             Aichi Prefecture Nagoya City Atsuta Ward Sakuradacho 19-18 East             Within Japan Gas Co., Ltd. (72) Inventor Kazuhiro Matsumoto             1-17-21 Chiyo 1-chome, Hakata-ku, Fukuoka City, Fukuoka Prefecture             Inside Seibu Gas Co., Ltd. F-term (reference) 4D034 CA06                 4D037 AA08 AB02 BA18

Claims (5)

[Claims] 1. A heat recovery device that heats and stores water in a heat storage tank by a heat exchanger in which a heat medium heated by heat generated by a heat source having a power generation function flows, and is heated by heat generated by the heat source. The temperature of the heat medium is equal to or lower than a required temperature, and a sterilizing unit for sterilizing water in the heat storage tank is provided, and the sterilizing unit is driven by being supplied with at least one of power generated by the heat source and power from a commercial power source. A heat recovery device characterized in that 2. The heat recovery device according to claim 1, wherein the heat source is a fuel cell and supplies electric power to a load, and the sterilizing means consumes power generated by the heat source to consume the load. A heat recovery device characterized in that surplus electric power exceeding the electric power is supplied and driven. 3. The heat recovery device according to claim 1, wherein the heat source is a fuel cell and supplies electric power to a load, and the sterilizing means is supplied with electric power at regular intervals. Heat recovery device characterized by being driven by. 4. The heat recovery device according to claim 1, wherein the sterilizing unit includes at least one of an electric heater and an ultraviolet ray irradiating unit, and the electric heater includes water in the heat storage tank and Heating at least one of the heat medium to bring the temperature of the water in the heat storage tank to a predetermined temperature or higher, and the ultraviolet irradiation means irradiates the water in the heat storage tank with ultraviolet rays. Characteristic heat recovery device. 5. A cogeneration system comprising the heat recovery device according to claim 1 and a polymer electrolyte fuel cell as the heat source having a power generation function.