JP5854369B2 - Cogeneration system - Google Patents

Description

  The present invention relates to a cogeneration system using a fuel cell or a gas engine.

As a cogeneration system using a fuel cell, there is a so-called water self-supporting system. Such a system has a heat exchange part for exhaust heat recovery that recovers heat from high-temperature exhaust gas discharged from a power generation part using a fuel cell. During the heat storage operation in the hot water storage tank, hot water in the hot water storage tank is supplied to the heat exchange unit, and heat exchange is performed between the hot water and the exhaust gas. Thus, water vapor in the exhaust gas discharged from the power generation unit is condensed, and this condensed water is supplied to an evaporator and used for fuel reforming.
On the other hand, the hot water heated by the exhaust gas is returned and stored in the hot water storage tank to store heat. In such a system, when the heat storage in the hot water storage tank is full, even if hot water in the hot water storage tank is supplied to the heat exchange unit, the exhaust gas from the power generation unit cannot be cooled, and condensed water is obtained. Disappear. In addition, a power generation unit of a high-temperature fuel cell such as SOFC takes a long time to start and stop operation, and it may be difficult to stop the operation every time the heat storage in the hot water storage tank becomes full.
Therefore, conventionally, when the heat storage in the hot water storage tank becomes full, the hot water flow path for circulating hot water between the separately provided radiator and the heat exchange part for exhaust heat recovery is switched to recover the exhaust heat. The hot water heated by the heat exchange unit is cooled by a radiator and then re-supplied to the heat exchange unit.

However, the prior art has the following problems.
That is, the radiator is usually configured to combine a heat exchange part for heat radiation and an air cooling fan for blowing air to the heat exchange part for heat radiation. The radiator having such a configuration has a relatively large size. Therefore, it has been difficult to secure a mounting space for the radiator. In addition, a heatsink including a fan is expensive.

  Patent Document 1 describes a cogeneration system in which the above-described radiator is not used. The system described in this document uses an auxiliary heat source device provided to heat hot water when the amount of heat stored in the hot water storage tank is insufficient as a radiator. More specifically, in Patent Document 1, the hot water to be cooled is supplied to the heat exchanging unit of the auxiliary heat source unit and is cooled by driving the fan of the auxiliary heat source unit. However, in such a means, when the burner of the auxiliary heat source machine is driven to burn and hot water heating is performed by the auxiliary heat source machine, it is difficult to cool the hot water, and the auxiliary heat source machine is used as a radiator. Cannot be used. This is inferior in practicality.

JP 2003-214705 A

  The present invention has been conceived under the circumstances as described above, and it is appropriate to reduce the size of a radiator for cooling hot water supplied to a heat exchanging part for exhaust heat recovery of a power generation part. The challenge is to provide a cogeneration system that can be used in the future.

  In order to solve the above problems, the present invention takes the following technical means.

A cogeneration system provided by the present invention has a hot water storage tank, a heat exchange part for exhaust heat recovery of a power generation part, an auxiliary heat source machine for hot water heating having a burner and a fan, and a radiator. A piping structure that connects the hot water storage tank and the heat exchanging part for exhaust heat recovery, and the piping structure is supplied from the hot water tank to the heat exchanging part for exhaust heat recovery and heated. A first state in which the hot water is returned to the hot water storage tank, and the hot water heated by the heat exchanger for exhaust heat recovery is cooled by the radiator and then circulated so as to be re-supplied to the heat exchanger. The cogeneration system is configured to be switchable between the second state, and the radiator is provided at a position to be an air flow passage when the fan of the auxiliary heat source unit sucks external air, Serial When the fan drive is configured so that the external air is supplied to the fan after passing through the heat exchanger for heat radiation of the radiator, the auxiliary heat source machine, the outer case having vents And the outside air of the outer case is supplied to the fan after flowing into the outer case through the vent, and the heat radiator By providing a case surrounding the periphery of the replacement part and providing the inside of the case so as to communicate with the vent of the outer case, the air outside the outer case can pass through the vent and the radiator. It is characterized by being configured to pass through the case .

According to such a configuration, the following effects can be obtained.
In other words, when the fan of the auxiliary heat source device is driven, the external air passes through the heat exchanging part for heat dissipation of the radiator based on the action of the fan sucking the external air. Therefore, it is not necessary to equip the radiator with a dedicated fan for sending air to the heat exchanger for air cooling of the radiator. As a result, it is possible to reduce the cost of the heatsink, reduce the size of the heatsink, and suppress problems such as difficulty in securing a space for mounting the heatsink.
According to the present invention, unlike the above-described Patent Document 1, even when the burner of the auxiliary heat source unit is being driven to burn, the heat exchange part for heat radiation of the radiator can be air-cooled. Therefore, there is no problem that it becomes difficult to supply cooling water to the heat exchange part for exhaust heat recovery of the power generation part when the burner of the auxiliary heat source machine is driven to burn, and it has excellent practicality. Become.
Furthermore, as an important effect, when the fan of the auxiliary heat source device is driven, the air that has risen in temperature through the heat exchange part of the radiator is sucked into the fan and taken into the auxiliary heat source device. Therefore, the heat of the air that has raised the temperature can be effectively used in the auxiliary heat source machine. For example, the heat can be used to heat a heat exchanger provided in the auxiliary heat source unit, or can be used to prevent freezing of each part of the auxiliary heat source unit. For this reason, according to the present invention, the heat released from the radiator is not wasted, and an effect of improving the energy efficiency of the entire system can be obtained.

Further , according to such a configuration, it is possible to efficiently send a large amount of external air into the radiator case when the fan of the auxiliary heat source unit is driven, while simplifying the overall configuration.

  In the present invention, preferably, the radiator is accommodated in the exterior case or attached to an outer surface portion of the exterior case, and the interior of the case of the radiator is in communication with the vent. Is provided.

  According to such a configuration, it is not necessary to connect the fan and the radiator of the auxiliary heat source unit using, for example, a duct, which is preferable in simplifying the overall configuration.

  Other features and advantages of the present invention will become more apparent from the following description of embodiments of the present invention with reference to the accompanying drawings.

It is a schematic explanatory drawing which shows an example of the cogeneration system which concerns on this invention. It is a schematic explanatory drawing which shows the other example of this invention. It is a schematic explanatory drawing which shows the other example of this invention.

  Hereinafter, preferred embodiments of the present invention will be specifically described with reference to the drawings.

  A cogeneration system C1 shown in FIG. 1 includes a fuel cell system 1, a hot water storage type hot water supply apparatus A, and a piping structure 2 that connects them. A heat radiator 5 is provided in the piping structure portion 2.

  The fuel cell system 1 is a so-called water self-supporting type, and is the same as that conventionally known. In brief, the fuel cell system 1 includes a power generation unit 10 using, for example, an SOFC (solid oxide fuel cell) and a heat exchange unit 11 for exhaust heat recovery. Although illustration explanation is omitted, the power generation unit 10 includes a cell stack, an evaporator, a fuel reformer, an off-gas combustion chamber, and the like, and discharges high-temperature exhaust gas along with a power generation operation. The heat exchange unit 11 for exhaust heat recovery is a part for recovering heat from the exhaust gas. When the exhaust gas is cooled in the heat exchange unit 11, condensed water is obtained. The condensed water is appropriately subjected to ion exchange treatment and the like, and then supplied to the evaporator and used for fuel reforming.

  The hot water supply apparatus A has a hot water storage tank 3 and an auxiliary heat source unit 4. A hot water discharge pipe 30 and a water inlet pipe 31 are connected to the upper and lower portions of the hot water storage tank 3, and the water pressure from the water inlet pipe 31 acts in the hot water storage tank 3. For this reason, when a tip (not shown) connected to the hot water outlet 30a of the hot water pipe 30 is opened, the hot water in the hot water storage tank 3 can be discharged from the hot water outlet 30a by the action of the incoming water pressure. It is.

  The auxiliary heat source unit 4 is for heating hot water when the amount of heat in the hot water storage tank 3 is insufficient. The auxiliary heat source unit 4 has the same configuration as that of an instantaneous gas water heater, for example, to blow air into the can body 43 so as to supply combustion air to the burner 40 and the burner 40 disposed in the can body 43. The heat exchanger 42 heats the hot water by recovering heat from the combustion gas generated by the fan 41 and the burner 40. In the present embodiment, the heat exchanger 42 of the auxiliary heat source unit 4 is connected to the pipe 20d connected to the upper part of the hot water storage tank 3, and the hot water flowing into the hot water storage tank 3 can be heated by the auxiliary heat source unit 4. Has been. However, the present invention is different from this, and it is also possible to adopt a configuration in which the hot water flowing through the tap water pipe 30 can be heated by the auxiliary heat source unit 4, and the installation location of the auxiliary heat source unit 4 does not matter.

  The piping structure unit 2 includes a plurality of pipings 20a to 20g, a pump P, and three-way valves V1 and V2, which are described later, and can supply hot water at a relatively low temperature to the heat exchanging unit 11 for heat recovery. is there. This piping structure part 2 can switch and set the 1st and 2nd state described below.

The first state is a state in which the hot water in the hot water storage tank 3 is sent to the heat exchange unit 11 for exhaust heat recovery, and the hot water heated by the heat exchange unit 11 is returned to the hot water storage tank 3. In this first state, when the pump P is driven, the hot water flowing out from the lower part of the hot water storage tank 3 flows along the path indicated by the arrows N11 to N14. Specifically, the hot water flowing out from the lower part of the hot water storage tank 3 is
The pipe 20 a, the heat exchange unit 11 for exhaust heat recovery, the pipes 20 b and 20 c, the heat exchanger 42 of the auxiliary heat source unit 4, and the pipe 20 d sequentially pass through and flow into the upper part of the hot water storage tank 3. Therefore, in the first state, the hot water in the hot water storage tank 3 can be heated using the heat exchanging portion 11 for recovering exhaust heat, and the hot water storage tank 3 can be stored. Further, in the heat exchange unit 11 for exhaust heat recovery, condensed water is obtained by cooling the exhaust gas discharged from the power generation unit 10 and condensing water vapor in the exhaust gas.

  The second state is a state in which hot water is circulated between the heat exchanger 11 for exhaust heat recovery and the radiator 5 and can be set by switching the hot water flow direction of the three-way valves V1, V2. In the second state, hot water flows along a route indicated by arrows N21 to N25. Specifically, when the pump P is driven, hot water on the discharge side of the pump P is sent to the radiator 5 through the three-way valve V1 and the pipe 20e, and thereafter passes through the pipes 20f and 20a. Then, it is sent to the heat exchange unit 11 for exhaust heat recovery. After that, it passes through the pipes 20b and 20g and returns to the pump P. When the second state is set, the hot water cooled by using the radiator 5 can be supplied to the heat exchange unit 11 for exhaust heat recovery. It is possible to cool appropriately in the heat exchange unit 11 and obtain condensed water. This second state is set when the amount of heat stored in the hot water storage tank 3 is full.

  The radiator 5 includes a heat exchange part 50 for heat radiation and a frame-like case 51 that surrounds the heat exchange part 50 for heat radiation and is open at both upper and lower sides. In the present embodiment, as will be described later, since the fan 41 of the auxiliary heat source unit 4 is also used as a fan for the radiator 5, the radiator 5 itself is not provided with an air cooling fan. The radiator 5 is accommodated in an outer case 6A that accommodates the auxiliary heat source unit 4 and is provided at a position that serves as an air flow path when the fan 41 sucks external air.

  More specifically, in the present embodiment, the vent 60 is provided in the bottom wall portion of the outer case 6 </ b> A, and when the fan 41 is driven, external air enters the outer case 6 </ b> A via the vent 60. It is configured to flow in. The radiator 5 is positioned so that the inside of the case 51 directly faces and communicates with the vent 60, and is attached to the bottom wall portion of the exterior case 6A. According to such a configuration, when the fan 41 is driven, the negative pressure suction force of the fan 41 reaches the inside of the case 51 of the radiator 5, and the air outside the outer case 6 </ b> A passes through the outer case 6 </ b> A. The air then passes through the vent 60 and the radiator 5 in order, flows into the outer case 6 </ b> A, and is then sucked into the air intake of the fan 41. The exterior case 6A may be either integral or separate from the exterior case 6B that accommodates the hot water storage tank 3, but when the two exterior cases 6A and 6B are integrally formed, the inside of the exterior case 6A and the like is a partition wall or the like. The flow rate of air passing through the vent 60 and the radiator 5 when the fan 41 is driven is ensured.

  Next, the operation of the above-described cogeneration system C1 will be described.

  When the heat storage state in the hot water storage tank 3 is full, the piping structure unit 2 is set to the second state described above, and hot water circulates between the radiator 5 and the heat exchange unit 11 for exhaust heat recovery. Is done. During this period, the fan 41 of the auxiliary heat source unit 4 is driven. When the fan 41 is driven, air outside the outer case 6 </ b> A is sucked by the fan 41 through the vent 60, but the entire amount of air that has passed through the vent 60 passes through the radiator 5. Therefore, the heat exchange part 50 for heat dissipation and the hot water flowing through the inside are efficiently cooled by this air circulation, and the cooling water can be appropriately supplied to the heat exchange part 11 for exhaust heat recovery. As a result, in the heat exchange part 11 for exhaust heat recovery, the exhaust gas is appropriately cooled, and condensed water that can be used for fuel reforming or the like can be obtained.

  Thus, in this embodiment, the fan 41 of the auxiliary heat source unit 4 is used as a means for causing the radiator 5 to function properly, and it is not necessary to provide a cooling fan in the radiator 5 itself. For this reason, the cost of the radiator 5 can be reduced, and the radiator 5 can be reduced in size and appropriately installed in a limited space in the exterior case 6A. The fan 41 of the auxiliary heat source device 4 can be driven at any time when the burner 40 is driven or not driven. Therefore, in the present embodiment, unlike the above-described Patent Document 1, even when the hot water is heated by driving the burner 40 of the auxiliary heat source unit 4, the radiator 5 is appropriately functioned to cool the hot water. The advantage that can be achieved is also obtained.

  The air that has passed through the radiator 5 contains heat released from the radiator 5, but this air is supplied from the fan 41 into the can body 43 of the auxiliary heat source unit 4. Therefore, in the auxiliary heat source unit 4, the heat can be recovered by the heat exchanger 42, and an effect of improving the energy efficiency of the entire system can be expected. In winter, it is possible to prevent the heat exchanger 42 from freezing by causing the air to act on the heat exchanger 42 of the auxiliary heat source device 4.

  2 and 3 show another embodiment of the present invention. In these drawings, elements that are the same as or similar to those in the above embodiment are given the same reference numerals as in the above embodiment.

  In the cogeneration system C2 shown in FIG. 2, the radiator 5 is attached to the lower surface portion of the bottom wall portion of the exterior case 6A. At the time of attachment, as in the above-described embodiment, the inside of the case 51 of the radiator 5 is in a state of directly facing and communicating with the vent 60 of the outer case 6A.

  According to the present embodiment, when the fan 41 is driven, it is possible to allow the outside air to pass through the case 51 of the radiator 5 and to appropriately exhibit the function of the radiator 5. it can. Although the heat radiator 5 is attached to the outer surface portion of the outer case 6A, this is suitable when it is difficult to secure a space for housing the heat radiator 5 in the outer case 6A.

  In the cogeneration system C <b> 3 shown in FIG. 3, the radiator 5 and the outer case 6 </ b> A are connected via a duct 7. The duct 7 forms an air flow path that connects the inside of the case 51 of the radiator 5 and the vent 60 of the exterior case 6A.

  Also according to this embodiment, when the fan 41 is driven, external air can be allowed to pass through the radiator 5 and then sucked into the fan 41, and the intended effect of the present invention can be obtained. From the viewpoint of reducing the number of parts and thoroughly reducing the manufacturing cost, as shown in FIG. 1 and FIG. 2, it is preferable to adopt a configuration that does not use a duct. A member may be used. When a duct is used, unlike the present embodiment, the radiator 5 and the intake port of the fan 41 may be directly connected, and an air flow passage may be formed between them.

  The present invention is not limited to the contents of the above-described embodiment. The specific configuration of each part of the cogeneration system according to the present invention can be variously modified within the intended scope of the present invention.

  The heat exchanging part for heat radiation of the radiator may be a structure that can obtain a heat radiation action by air cooling, and its specific configuration is not limited. The auxiliary heat source machine is only required to be able to heat hot water by being provided with a burner and a fan. As the burner, for example, an oil burner can be used instead of a gas burner.

  The cogeneration system according to the present invention is not limited to the one provided with the water self-supporting fuel cell system, but can be configured as a fuel cell system other than this or a system using a gas engine. In the cogeneration system, instead of or in addition to obtaining condensed water in the heat exchanging unit for exhaust heat recovery of the power generation unit, for example, for the purpose of preventing temperature rise of the power generation unit, etc., waste heat recovery from the power generation unit In such a case, the present invention is also effective. The auxiliary heat source unit may be used even when the hot water storage state of the hot water storage tank is full. For example, the auxiliary heat source unit is appropriately operated when performing heating hot water supply or bath hot water supply with high heat consumption. .

C1 to C3 Cogeneration system A Hot water supply device 1 Fuel cell system 2 Piping structure 3 Hot water storage tank 4 Auxiliary heat source unit 5 Radiator 6A Exterior case 10 Power generation unit 11 Heat exchange unit 40 for exhaust heat recovery Burner (auxiliary heat source unit)
41 Fan (for auxiliary heat source)
50 Heat exchange part for heat dissipation (of radiator)
51 Case (for radiator)
60 Vent (outer case)

Claims (2)

A hot water storage tank,
A heat exchanging part for exhaust heat recovery of the power generation part;
An auxiliary heat source machine for hot water heating having a burner and a fan;
A piping structure part having a radiator and connecting the hot water storage tank and the heat exchange part for exhaust heat recovery, and
The piping structure section is heated by the first state in which the hot water supplied from the hot water storage tank to the heat exchanging section for exhaust heat recovery is returned to the hot water storage tank, and the heat exchanging section for exhaust heat recovery. A cogeneration system that can be switched and set to a second state in which the hot water is cooled by the radiator and then circulated so as to be re-supplied to the heat exchange unit,
The radiator is provided at a position to be an air flow path when the fan of the auxiliary heat source apparatus sucks external air, and when the fan is driven, the external air passes through a heat exchange part for heat dissipation of the radiator. It is configured to be supplied to the fan from,
The auxiliary heat source unit is accommodated in an outer case having a vent hole, and is configured such that outside air of the outer case flows into the outer case through the vent hole and then is supplied to the fan. And
The radiator includes a case that surrounds the heat exchange part for heat dissipation, and the inside of the case is provided so as to communicate with the vent of the exterior case. The cogeneration system is configured such that air passes through the vent and the case of the radiator . The cogeneration system according to claim 1,
The radiator is housed in the exterior case or attached to an outer surface portion of the exterior case, and the interior of the case of the radiator is provided so as to communicate with the vent. Generation system.

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