JP7415754B2 - Hot water storage system, drainage method for hot water storage system, and fuel cell system - Google Patents

Description

The present invention relates to a hot water storage system, a drainage method for the hot water storage system, and a fuel cell system.

Conventionally, this type of hot water storage system has an air venting pipe connected to the top of the hot water storage tank to communicate the inside of the hot water storage tank with the outside space, an automatic air venting valve installed in the air venting pipe, and a hot water storage tank. A device including a drain pipe connected to the bottom surface of the drain pipe and a drain valve provided on the drain pipe has been proposed (for example, see Patent Document 1). With this system, when a drainage command is input, the automatic air vent valve and drain valve open, allowing smooth drainage without creating negative pressure in the hot water storage tank. .

Japanese Patent Application Publication No. 2010-78189

By the way, in a hot water storage system that includes a heat exchanger that exchanges heat between high-temperature fluid and hot water, a hot water storage tank that stores the hot water, and circulation piping that connects the heat exchanger and the hot water storage tank, due to the layout of the system, A trap portion where hot water is trapped (accumulated) may be formed in the circulation piping. In this case, it is desirable to efficiently drain not only the water in the hot water storage tank but also the hot water trapped in the trap section with a simple configuration.

The main object of the present invention is to effectively drain the tank and the trap part with a simple structure in a device having a trap part in a part of a circulation pipe connecting a heat exchanger and a tank.

The present invention employs the following means to achieve the above-mentioned main objective.

The fuel cell system of the present invention includes:
a heat exchanger that exchanges heat between high-temperature fluid and hot water;
A tank that stores hot water,
circulation piping that connects the heat exchanger and the tank so that hot water circulates, and has a trap part that traps hot water;
a pump that circulates hot water in the circulation pipe;
a first drain pipe that drains hot water in the tank;
a first opening/closing member that opens and closes the outlet of the first drain pipe;
a second drain pipe connected to the lowest point of the trap section;
a second opening/closing member that is installed at a higher position than the first opening/closing member and opens and closes the outlet of the second drain pipe;
The main point is to have the following.

In the hot water storage system of the present invention, the heat exchanger and the tank are connected so that the hot water circulates, and a circulation pipe has a trap part that traps the hot water, and a first drain pipe that drains the hot water in the tank. a first opening/closing member that opens and closes the outlet of the first drain pipe; a second drain pipe connected to the lowest point of the trap section; and a second opening/closing member that opens and closes the outlet of the second drain pipe. . The second opening/closing member is installed at a higher position than the first opening/closing member. As a result, by opening the first opening/closing member, the hot water in the tank is drained from the outlet of the first drain pipe, and by opening the second opening/closing member, the hot water trapped in the trap section is discharged. Water is drained from the outlet of the first drain pipe mainly by being pushed out by air introduced from the second drain pipe due to the negative pressure generated as hot water in the tank is drained. As a result, the tank and trap portion can be drained well. Further, by performing main drainage through the first drain pipe, the second drain pipe and the second opening/closing member can be made simpler, and costs can be reduced.

In such a hot water storage system of the present invention, the second drain pipe may have a smaller pipe diameter than the circulation pipe and the first drain pipe. In this way, the amount of water discharged from the second drain pipe can be reduced as much as possible, making it unnecessary to carry out drainage work to guide the waste water from the second water pipe to a predetermined drainage location.

Further, in the hot water storage system of the present invention, the first opening/closing member and the second opening/closing member may be configured to be manually operable to open/close. This allows the tank and trap to be drained even when the system is powered down.

Furthermore, in the hot water storage system of the present invention, the second opening/closing member is configured to operate when the second opening/closing member is closed and the first opening/closing member is opened to drain hot water from the outlet of the first drain pipe. The tank may be installed so that the water head height of the tank is higher than the water head height of the trap section when the negative pressure acting in the tank due to drainage and the water head pressure of the tank are balanced. good. By doing this, by opening the second opening/closing member while negative pressure is acting in the tank, the negative pressure will more reliably introduce air from the second drain pipe, and the hot water in the trap will be drained into the first drain. Allows for smooth drainage from the pipe. The hot water storage system of the present invention in this aspect includes a negative pressure release valve that opens to release the negative pressure in the tank when a negative pressure exceeding a set pressure acts in the tank, and the second opening/closing member When hot water is drained from the outlet of the first drain pipe by opening the first opening/closing member in a state where the drain pipe is closed, the negative pressure acting in the tank due to draining is balanced with the water head pressure of the tank. The negative pressure at this time may be smaller in absolute value than the set pressure of the negative pressure release valve. In this way, it is possible to prevent the negative pressure that acts within the tank due to drainage from the first drain pipe from being released by the negative pressure release valve.

The drainage method of the hot water storage system of the present invention is as follows:
a heat exchanger that exchanges heat between high-temperature fluid and hot water;
A tank that stores hot water,
circulation piping that connects the heat exchanger and the tank so that hot water circulates, and has a trap part that traps hot water;
a pump that circulates hot water in the circulation pipe;
a first drain pipe for draining hot water in the tank;
a first opening/closing member that opens and closes the outlet of the first drain pipe;
a second drain pipe connected to the lowest point of the trap section;
A drainage method for a hot water storage system, comprising: a second opening/closing member installed at a higher position than the first opening/closing member and opening/closing an outlet of the second drain pipe,
When draining hot water in the hot water storage tank and the trap section, open the first opening/closing member, and then open the second opening/closing member;
The gist is that.

In the hot water storage system of the present invention, in the above-described hot water storage system of the present invention, when draining the hot water in the hot water storage tank and the trap section, the first opening/closing member is opened, and then the second opening/closing member is opened. . Thereby, by opening the first opening/closing member while the second opening/closing member is closed, hot water in the tank is drained from the outlet of the first drain pipe. As the hot water in the tank continues to drain, a negative pressure acts on the tank, and eventually the negative pressure acting on the tank balances out with the water head pressure of the tank, stopping the draining from the outlet of the first drain pipe. When the second opening/closing member is opened, air is introduced from the outlet of the second drain pipe due to the negative pressure inside the tank, and the hot water trapped in the trap section is mainly pushed out by the air and circulated through the circulation pipe. and is drained from the outlet of the first drain pipe. As a result, the tank and trap portion can be drained well. Further, by performing main drainage through the first drain pipe, the second drain pipe and the second opening/closing member can be made simpler, and costs can be reduced.

The fuel cell system of the present invention includes:
a fuel cell module including a fuel cell;
a heat exchanger that exchanges heat between the exhaust gas from the fuel cell module and hot water; a tank that stores the hot water; and the heat exchanger and the tank are connected so that the hot water circulates, and the hot water is partially trapped. a pump for circulating hot water in the circulation pipe; a first drain pipe for draining hot water in the tank; and a first opening/closing member for opening and closing an outlet of the first drain pipe. , a hot water storage having a second drain pipe connected to the lowest point of the trap section, and a second opening/closing member installed at a higher position than the first opening/closing member and opening/closing the outlet of the second drain pipe. system and
a casing that accommodates the fuel cell module and the hot water storage system;
The main point is to have the following.

Since the fuel cell system of the present invention includes the above-described hot water storage system of the present invention in addition to the fuel cell module, the effect of the hot water storage system of the present invention, that is, the tank and trap portion can be drained well. By performing the main drainage through the first drain pipe, the second drain pipe and the second opening/closing member can be made simpler, resulting in lower costs. I can do it.

The fuel cell system of the present invention includes a radiator installed upstream of the heat exchanger and downstream of the hot water storage tank in the flow direction of hot water in the circulation piping, and the heat exchanger is connected to the fuel cell module. connected to the bottom of the fuel cell module, having an exhaust inlet for introducing exhaust gas from the fuel cell module, a hot water outlet for leading out hot water that has undergone heat exchange with the exhaust gas at the top, and a hot water inlet for introducing the hot water at the bottom; The radiator may be installed close to the bottom of the fuel cell module, and the trap portion may be formed on a path from the radiator to a flow path of hot water inside the heat exchanger. In this way, the radiator can be disposed in the empty space at the bottom of the fuel cell module, and the trap formed thereby can be drained well, so that the system can be made more compact.

FIG. 1 is an external view of the fuel cell system of this embodiment. FIG. 1 is a configuration diagram schematically showing the configuration of a fuel cell system according to the present embodiment.

Embodiments for carrying out the present invention will be described with reference to the drawings.

FIG. 1 is an external view of the fuel cell system of this embodiment, and FIG. 2 is a configuration diagram showing an outline of the configuration of the fuel cell system of this embodiment. As shown in the figure, the fuel cell system 10 includes a fuel cell module 20 including a fuel cell stack, and an exhaust system that heats hot water using exhaust heat from the fuel cell module 20 and stores the hot water in a hot water storage tank 32 to recover the exhaust heat. It is configured as a cogeneration system including a heat recovery device 30 and a box-shaped housing 11 that houses them.

Although not shown, the fuel cell module 20 includes a vaporizer that vaporizes reformed water to generate water vapor, and a reformer that vaporizes raw fuel gas (for example, natural gas or LP gas) to generate fuel gas. It has a fuel cell stack that generates electricity through an electrochemical reaction between fuel gas and air, and a combustion section that burns off-gas discharged from the fuel cell stack. These are housed in a module case 21 made of a heat insulating material, and are installed in the upper part of the housing 11, as shown in FIG. In addition, in the lower part of the housing 11, there is a gas pump that supplies raw fuel gas to the reformer, a water tank 22 that stores reformed water, and water that pumps reformed water from the water tank 22 and supplies it to the vaporizer. Various auxiliary equipment such as a pump and an air pump that supplies air to the fuel cell stack are installed.

In addition, an exhaust gas outlet is formed at the bottom of the module case 21 for discharging the combustion exhaust gas generated by combustion of off-gas in the combustion section, and the exhaust gas outlet is provided with heat generated by the combustion exhaust gas and hot water. A heat exchanger 31 of an exhaust heat recovery device 30 that performs exchange is connected.

The exhaust heat recovery device 30 is installed in the lower part of the housing 11 together with the various auxiliary equipment described above, and as shown in FIG. A circulation pipe 33a connecting the bottom of the tank 32 and the lower part of the heat exchanger 31, a circulation pipe 33b connecting the top of the heat exchanger 31 and the top of the hot water storage tank 32, and a pump 34 built into the circulation pipe 33a. It has a heater unit 35, a radiator 36, and a radiator fan (electric fan) that sends air to the radiator 36. The exhaust heat recovery device 30 takes out low-temperature hot water from the bottom of the hot water storage tank 32 and transfers the taken-out low-temperature hot water to the heat exchanger 31 by operating the pump 34 and circulating the hot water in the circulation pipes 33a and 33b. The hot water is heated by heat exchange with high-temperature combustion exhaust gas and returned to the top of the hot water storage tank 32. In the heat exchanger 31, moisture contained in the combustion exhaust gas is condensed by heat exchange with hot water and stored in the water tank 22 as condensed water.

In this embodiment, the heat exchanger 31 is configured as a countercurrent type heat exchanger in which the flow direction of combustion exhaust gas and the flow direction of hot water are opposite to each other. An exhaust gas inlet connected to the exhaust gas outlet and a hot water outlet connected to the circulation pipe 33b (on the top side of the hot water storage tank 32) are formed, and a condensed water outlet connected to the water tank 22 is formed at the bottom of the heat exchanger 31. An exhaust gas outlet for discharging the condensed exhaust gas into the atmosphere, and a hot water inlet connected to the circulation pipe 33a (radiator 36 side) are formed.

At the bottom of the hot water storage tank 32, in addition to the circulation piping 33a, a water supply port is formed to supply pressurized water, and at the top of the hot water storage tank 32, in addition to the circulation piping 33b, a hot water outlet is formed to dispense hot water. By supplying pressurized water to the hot water storage tank 32 through the water supply port, hot water is discharged from the hot water outlet at the top of the hot water storage tank 32 to the hot water supply location via the hot water tap piping 51. A negative pressure release valve 52 is attached to the hot water tap piping 51, and when negative pressure exceeding the set pressure of the negative pressure release valve 52 acts in the hot water storage tank 32, the negative pressure release valve 52 opens. , the negative pressure is released to prevent damage to the hot water storage tank 32.

The heater unit 35 includes a unit case and a heater (for example, a ceramic heater) built into the unit case. Heats the low-temperature hot water flowing into the unit case. Furthermore, in this embodiment, the heater unit 35 is arranged at the lowest point of the circulation pipes 33a and 33b, and the unit case of the heater unit 35 is provided with a tank drain pipe for discharging hot water in the hot water storage tank 32. 41 is connected. As shown in FIG. 1, the outlet of the tank drain pipe 41 is formed at the lower side of the housing 11, and a tank drain valve 43 is attached to the outlet of the tank drain pipe 41. In this embodiment, the tank drain valve 43 is a manual ball valve, and is configured to be openable and closable by manual operation.

The radiator 36 is installed close to the bottom of the fuel cell module 20 (module case 21). As a result, a trap portion 33t in which hot water is trapped is formed on the path from the radiator 36 to the hot water flow path inside the heat exchanger 31. A trap drain pipe 42 is connected to the lowest portion of the trap portion 33t. In this embodiment, the trap drain pipe 42 has a smaller pipe diameter than the circulation pipes 33a, 33b and the tank drain pipe 41. As shown in FIG. 1, the outlet of the trap drain pipe 42 is formed at the lower side of the housing 11, and a trap drain valve 44 is attached to the outlet of the trap drain pipe 42. In this embodiment, the trap drain valve 44 is a simple water stop valve (plug), and like the tank drain valve 43, it is configured to be openable and closable by manual operation.

The trap drain valve 44 (the outlet of the trap drain pipe 42) is installed at a higher position than the tank drain valve 43 (the outlet of the tank drain pipe 41). That is, as shown in FIG. 2, the height of the tank drain valve 43 and the trap drain valve 44 to the highest point in the circulation pipes 33a, 33b with the tank drain valve 43 as a reference is the same as that of the trap drain valve 44 with the trap drain valve 44 as a reference. It is installed so that it is higher than the height to the top point above.

When the fuel cell system 10 is not used for a long period of time, water is drained from the hot water tank 32 and the circulation pipes 33a and 33b. In the fuel cell system 10 of this embodiment, when draining water, the operator first opens only the tank drain valve 43 of the tank drain valve 43 and the trap drain valve 44. When the trap drain valve 44 is closed and the tank drain valve 43 is opened, the hot water in the hot water storage tank 32 and the hot water in the circulation pipes 33a and 33b excluding the trap section 33t are transferred to the circulation pipe 33a or the circulation pipe 33b. The water flows through to the lowest point (heater unit 35) of the circulation pipes 33a, 33b, and is drained outside from the outlet of the tank drain pipe 41 connected to the lowest point. As hot water drains, a negative pressure acts inside the hot water storage tank 32, and eventually the negative pressure acting inside the hot water storage tank 32 and the water head pressure of the hot water storage tank 32 are balanced, and drainage from the tank drain pipe 41 is stopped.

Next, the operator opens the trap drain valve 44 while keeping the tank drain valve 43 open. In this embodiment, the trap drain valve 44 has a water head height (h1 in FIG. 2) of the hot water storage tank 32 when balanced with the negative pressure acting inside the hot water storage tank 32, which is equal to the water head height of the trap portion 33t (FIG. 2). It is installed so that it is higher than medium, h2). Therefore, when the trap drain valve 44 is opened, air is introduced from the outlet of the trap drain pipe 42 by the negative pressure acting in the hot water storage tank 32, and the hot water in the trap section 33t is pushed out by the air. The hot water flows through the circulation pipe 33b on the hot water storage tank 32 side or the circulation pipe 33a on the radiator 36 side, and is drained from the outlet of the tank drain pipe 41. Thereby, the hot water storage tank 32 and the trap section 33t can be drained well, and the hot water storage tank 32 and the trap section 33t can be drained mainly through the tank drain pipe 41.

In addition, since the trap drain pipe 42 is formed with a smaller pipe diameter than the circulation pipes 33a, 33b and the tank drain pipe 41, the hot water drained from the trap drain pipe 42 when the trap drain valve 44 is opened is The high pressure drop in the trap drain 42 minimizes this. This makes it possible to eliminate the need for drainage work to guide hot water from the trap drain pipe 42 to the drainage location.

Here, in the hot water storage system of this embodiment, a negative pressure release valve 52 is installed in the piping (hot water outlet piping 51) connected to the hot water storage tank 32, and a negative pressure exceeding the set pressure is released inside the hot water storage tank 32. When this happens, the negative pressure release valve 52 is opened, and the negative pressure in the hot water storage tank 32 is released. Therefore, when the trap drain valve 44 is closed and the tank drain valve 43 is opened, when the negative pressure that acts in the hot water storage tank 32 and the head pressure of the hot water storage tank 32 are balanced, the negative pressure becomes negative. If the pressure exceeds the set pressure (opening pressure) of the pressure release valve 52, the negative pressure will be released by the negative pressure release valve 52, and even if the trap drain valve 44 is opened, air will not be drained from the trap drain pipe 42. It will not be possible to introduce it. Therefore, in the hot water storage system of this embodiment, when the trap drain valve 44 is closed and the tank drain valve 43 is opened, the negative pressure that acts within the hot water storage tank 32 and the water head pressure of the hot water storage tank 32 are balanced. The negative pressure at this time is designed to be smaller in absolute value than the set pressure of the negative pressure release valve 52. As a result, air is introduced from the trap drain pipe 42 by utilizing the negative pressure inside the hot water storage tank 32 that is generated as water is drained from the tank drain pipe 41, and the air introduced into the trap section 33t causes hot water to enter the trap section 33t. The hot water can be pushed out and drained from the tank drain pipe 41.

The fuel cell system 10 of the present embodiment described above includes circulation pipes 33a and 33b that connect the heat exchanger 31 and the hot water storage tank 32 and have a trap section 33t that partially traps hot water; A tank drain pipe 41 that drains hot water, a tank drain valve 43 that opens and closes the outlet of the tank drain pipe 41, a trap drain pipe 42 that opens and closes the outlet of the trap section 33t, and a trap drain pipe 42 that opens and closes the outlet of the trap drain pipe 42. A trap drain valve 44 is provided. The trap drain valve 44 (the outlet of the trap drain pipe 42) is installed at a higher position than the tank drain valve 43 (the outlet of the tank drain pipe 41). As a result, by opening the tank drain valve 43, the hot water in the hot water storage tank 32 is drained from the tank drain pipe 41, and by opening the trap drain valve 44, the hot water in the trap portion 33t is drained. The water is drained from the tank drain pipe 41 mainly by being pushed out by air introduced from the trap drain pipe 42 under negative pressure generated by draining hot water in the hot water storage tank 32 . As a result, the hot water storage tank 32 and the trap portion 33t can be drained well. Further, by performing main drainage through the tank drain pipe 41, the trap drain pipe 42 and the trap drain valve 44 can be made simpler, and costs can be reduced.

Furthermore, in the fuel cell system 10 of the present embodiment, the trap drain pipe 42 is formed with a smaller pipe diameter than the circulation pipes 33a, 33b and the tank drain pipe 41. As a result, drainage from the trap drain pipe 42 can be minimized due to the high pressure loss of the trap drain pipe 42. As a result, drainage work for guiding the drainage from the trap drain pipe 42 to the drainage location can be made unnecessary. In addition, a drain valve with a simple structure is adopted as the trap drain valve 44, and the trap drain pipe 42 is made of resin to improve durability by reducing the pipe diameter of the trap drain pipe 42. It becomes possible to further reduce costs.

Furthermore, in the fuel cell system 10 of the present embodiment, the tank drain valve 43 and the trap drain valve 44 are configured to be openable and closable by manual operation. Hot water in the trap portion 33t can be drained.

In this embodiment, the tank drain valve 43 and the trap drain valve 44 are configured to be openable and closable by manual operation, but are configured to be openable and closable by automatic operation based on a control signal from the control device of the fuel cell system 10. Alternatively, the configuration may be such that both manual operation and automatic operation are possible.

In this embodiment, the tank drain pipe 41 is connected to the heater unit 35 installed at the lowest point of the circulation pipes 33a, 33b, but it may be connected to the bottom of the hot water storage tank 32.

In this embodiment, the present invention has been described as applied to the fuel cell system 10, but the present invention is not limited thereto, and may be in the form of a hot water storage system or as a drainage method of the hot water storage system.

The correspondence between the main elements of the embodiment and the main elements of the invention described in the section of means for solving the problems will be explained. In the embodiment, the heat exchanger 31 corresponds to a "heat exchanger", the hot water storage tank 32 corresponds to a "tank", the circulation pipes 33a and 33b correspond to "circulation pipes", and the trap part 33t corresponds to a "trap part". ”, the pump 34 corresponds to the “pump”, the tank drain pipe 41 corresponds to the “first drain pipe”, the tank drain valve 43 corresponds to the “first opening/closing member”, and the trap drain pipe 42 corresponds to the “first drain pipe”. This corresponds to a "second drain pipe," and the trap drain valve 44 corresponds to a "second opening/closing member." Further, the fuel cell module 20 corresponds to a "fuel cell module", and the casing 11 corresponds to a "casing". Further, the radiator 36 corresponds to a "radiator".

The correspondence relationship between the main elements of the embodiment and the main elements of the invention described in the column of means for solving the problem is that the embodiment implements the invention described in the column of means for solving the problem. Since this is an example for specifically explaining a form for solving the problem, it is not intended to limit the elements of the invention described in the column of means for solving the problems. In other words, the interpretation of the invention described in the column of means for solving the problem should be made based on the description in that column, and the embodiments should be based on the description of the invention described in the column of means for solving the problem. This is just one specific example.

Although the mode for implementing the present invention has been described above using the embodiments, the present invention is not limited to these embodiments in any way, and may be modified in various forms without departing from the gist of the present invention. Of course, it can be implemented.

INDUSTRIAL APPLICATION This invention can be utilized for the manufacturing industry of a hot water storage system and a fuel cell system, etc.

10 fuel cell system, 11 housing, 20 fuel cell module, 21 module case, 30 exhaust heat recovery device, 31 heat exchanger, 32 hot water storage tank, 33a, 33b circulation piping, 33t trap section, 34 pump, 35 heater unit, 36 Radiator, 41 Tank drain pipe, 42 Trap drain pipe, 43 Tank drain valve, 44 Trap drain valve.

Claims (7)

a heat exchanger that exchanges heat between high-temperature fluid and hot water;
A tank that stores hot water,
circulation piping that connects the heat exchanger and the tank so that hot water circulates, and has a trap part that traps hot water;
a pump that circulates hot water in the circulation pipe;
a first drain pipe for draining hot water in the tank;
a first opening/closing member that opens and closes the outlet of the first drain pipe;
a second drain pipe connected to the lowest point of the trap section;
a second opening/closing member that is installed at a higher position than the first opening/closing member and opens and closes the outlet of the second drain pipe;
Equipped with
The second opening/closing member acts on the inside of the tank as the hot water is drained from the outlet of the first drain pipe by opening the first opening/closing member with the second opening/closing member closed. The tank is installed so that the water head height of the tank is higher than the water head height of the trap section when the negative pressure of the tank is balanced with the water head pressure of the tank.
Hot water storage system. The hot water storage system according to claim 1,
The second drain pipe has a smaller pipe diameter than the circulation pipe and the first drain pipe.
Hot water storage system. The hot water storage system according to claim 1 or 2,
The first opening/closing member and the second opening/closing member are configured to allow manual opening/closing operation.
Hot water storage system. The hot water storage system according to any one of claims 1 to 3 ,
comprising a negative pressure release valve that opens to release the negative pressure in the tank when negative pressure exceeding a set pressure acts in the tank;
When hot water is drained from the outlet of the first drain pipe by opening the first opening/closing member with the second opening/closing member closed, the negative pressure that acts within the tank due to drainage and the pressure of the tank The negative pressure when balanced with the water head pressure is smaller in absolute value than the set pressure of the negative pressure release valve.
Hot water storage system. a heat exchanger that exchanges heat between high-temperature fluid and hot water;
A tank that stores hot water,
circulation piping that connects the heat exchanger and the tank so that hot water circulates, and has a trap part that traps hot water;
a pump that circulates hot water in the circulation pipe;
a first drain pipe that drains hot water in the tank;
a first opening/closing member that opens and closes the outlet of the first drain pipe;
a second drain pipe connected to the lowest point of the trap section;
a second opening/closing member that is installed at a higher position than the first opening/closing member and opens and closes the outlet of the second drain pipe;
The second opening/closing member acts on the inside of the tank as the hot water is drained from the outlet of the first drain pipe by opening the first opening/closing member with the second opening/closing member closed. A water drainage method for a hot water storage system, wherein the water head height of the tank is higher than the water head height of the trap section when the negative pressure of the tank is balanced with the water head pressure of the tank,
When draining the hot water in the tank and the trap section, open the first opening/closing member, and then open the second opening/closing member;
How to drain a hot water storage system. a fuel cell module including a fuel cell;
a heat exchanger that exchanges heat between the exhaust gas from the fuel cell module and hot water; a tank that stores the hot water; and the heat exchanger and the tank are connected so that the hot water circulates, and the hot water is partially trapped. a pump for circulating hot water in the circulation pipe; a first drain pipe for draining hot water in the tank; and a first opening/closing member for opening and closing an outlet of the first drain pipe. , a hot water storage having a second drain pipe connected to the lowest point of the trap section, and a second opening/closing member installed at a higher position than the first opening/closing member and opening/closing the outlet of the second drain pipe. system and
a casing that accommodates the fuel cell module and the hot water storage system;
A fuel cell system equipped with The fuel cell system according to claim 6 ,
comprising a radiator installed upstream of the heat exchanger and downstream of the tank in the flow direction of hot water in the circulation piping,
The heat exchanger is connected to the bottom of the fuel cell module, and has an exhaust inlet for introducing exhaust gas from the fuel cell module, and a hot water outlet for leading out hot water that has undergone heat exchange with the exhaust gas, at an upper part, and has an It has a hot water inlet at the bottom to introduce hot water.
The radiator is installed close to the bottom of the fuel cell module,
The trap section is formed on a path from the radiator to a flow path of hot water inside the heat exchanger.
fuel cell system.

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