JP2005265293A - Waste heat utilizing system of fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a waste heat utilizing system of a fuel cell capable of raising temperature of hot water so that it is applicable to a desiccant air conditioner and amount of heat reserve in a hot-water storage tank is increased. <P>SOLUTION: This waste heat utilizing system of the fuel cell is provided with the fuel cell 2 for generating electricity and heat, the hot-water storage tank 4 storing heat as hot water, a solar heat collection device 6 for heating water by utilizing solar heat, the desiccant air conditioner 8, a cooling water circulation flow passage 12 for circulating cooling water of the fuel cell, a stored hot-water circulation flow passage 14 for circulating water in the hot-water storage tank 4, a heat exchanger 16 performing heat exchange between cooling water in the cooling water circulation flow passage 12 and water in the stored hot-water circulation flow passage 14, a first hot-water feeding flow passage 22 for feeding hot water after heat exchange into the solar heat collection device 6, a second hot-water feeding flow passage 24 for feeding hot water from the solar heat collection device 6 toward the hot-water storage tank 4, and a hot-water feeding flow passage 26 for feeding hot water toward the desiccant air conditioner 8. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an exhaust heat utilization system that utilizes exhaust heat of a fuel cell.

  In recent years, fuel cells that generate electricity and heat have been developed from the viewpoints of environmental problems, energy efficiency, and the like, and polymer electrolyte fuel cells having a low operating temperature for fuel cell reactions have attracted attention as household fuel cells. An exhaust heat utilization system using such a fuel cell includes a fuel cell that generates electricity and heat, a hot water storage tank that stores exhaust heat as hot water, a cooling water circulation passage that circulates cooling water through the fuel cell, and a hot water storage tank A hot water circulation channel for circulating the internal water, and a heat exchanger for exchanging heat between the cooling water flowing through the cooling water circulation channel and the water flowing through the hot water circulation channel. In such an exhaust heat utilization system, the exhaust heat of the fuel cell is transmitted to the hot water storage tank via the cooling water flowing through the cooling water circulation channel and the water flowing through the hot water circulation channel, and is stored as hot water in the hot water storage tank.

  In such an exhaust heat utilization system, when a polymer electrolyte fuel cell is used as the fuel cell, the operating temperature of the fuel cell reaction is low (for example, about 80 ° C.), and therefore the exhaust heat temperature is also low (for example, Therefore, it is difficult to keep the temperature of the hot water stored in the hot water tank high, and the use of the hot water stored in the hot water tank is mainly for hot water supply.

  In such a waste heat utilization system, if the heat demand (for hot water supply) is extremely small compared to the power demand, as in the summer, and the heat demand and the power demand are largely unbalanced, the exhaust heat of the fuel cell is sufficient. Can not be used for energy efficiency. In addition, when the heat demand (for hot water supply) is larger than the power demand as in the winter season, the hot water stored in the hot water tank cannot sufficiently meet the heat demand, and an auxiliary heat source (for example, an auxiliary boiler) ) Will operate, and even in such a case, energy efficiency is reduced.

  For this reason, there has also been proposed a device in which the exhaust heat of the fuel cell is further heated using the exhaust heat of a heater, for example, a gas engine (see, for example, Patent Document 1). In this exhaust heat utilization system, the exhaust heat of the fuel cell is further heated using the exhaust heat of the gas engine, and the regenerated air supplied to the desiccant wheel of the desiccant air conditioner using this heated exhaust heat. Is heated to a regeneration temperature, for example, about 80 ° C. Therefore, the exhaust heat of the fuel cell can be used for heating the desiccant air conditioner, and the exhaust heat of the fuel cell can be effectively used.

JP 2003-279070 A

  However, in the exhaust heat utilization system described above, the exhaust heat of the fuel cell is heated using the exhaust heat of a gas engine or the like and applied to the desiccant air conditioner. In this way, the exhaust heat can be effectively used to increase the energy efficiency. However, when the desiccant air conditioner is not operated, the exhaust heat of the fuel cell and the exhaust heat of the gas engine cannot be effectively utilized. There is a problem that efficiency decreases.

  An object of the present invention is to effectively use the exhaust heat of a fuel cell, to increase the temperature of hot water so that it can be applied to a desiccant air conditioner in summer, and to increase the amount of heat stored in a hot water tank in winter. Another object of the present invention is to provide a fuel cell exhaust heat utilization system capable of increasing the temperature of hot water.

A fuel cell exhaust heat utilization system according to claim 1 of the present invention is a fuel cell that generates electricity and heat, a hot water storage tank for storing heat as hot water, and heating water using solar heat. A solar heat collecting device, a heat consuming device that consumes heat, a cooling water circulation passage that circulates cooling water through the fuel cell, a hot water circulation passage that circulates water in the hot water tank, and the hot water circulation flow A first hot water feed channel for feeding water flowing through the path to the solar heat collector, a second hot water feed channel for feeding hot water from the solar heat collector to the hot water storage tank, and the solar heat A third hot water supply passage that feeds hot water from the heat collector toward the heat consuming device, a consumed hot water circulation passage that circulates hot water through the heat consuming device, and cooling that flows through the cooling water circulation passage To exchange heat between the water and the water flowing through the hot water circulation passage Comprising a first heat exchanger, and a second heat exchanger for exchanging heat between the third hot water flowing hot water through the hot water feed channel to the consumption hot-water circulation passage,
When the water in the hot water storage tank is heated using the solar heat collecting device, the water in the hot water storage tank flows through the hot water storage circulation path and the first heat exchanger, and the first heat exchanger Heat exchanged with the cooling water circulating through the cooling water circulation flow path, and then fed through the first hot water feed flow path to the solar heat collecting device and heated by the solar heat collecting device. Returned to the hot water storage tank through the second hot water supply passage,
When the solar heat collecting device is used for heating and consumption by the heat consuming device, the water in the hot water storage tank flows through the hot water storage water circulation channel and the first heat exchanger, and In one heat exchanger, heat is exchanged with the cooling water circulating through the cooling water circulation flow path, and then supplied to the solar heat collecting apparatus through the first hot water supply flow path, and is added by the solar heat collecting apparatus. After being heated, it flows through the third hot water supply passage, and heat is exchanged with the hot water flowing through the consumed hot water circulation passage in the second heat exchanger.

  Further, in the fuel cell exhaust heat utilization system according to claim 2 of the present invention, in addition to the configuration according to claim 1, the downstream side of the third hot water supply passage is provided with first and second branch feeds. The first branch feed channel is connected to the hot water storage tank, and the second branch feed channel is connected upstream of the first heat exchanger of the hot water circulation channel. When the temperature of the hot water flowing through the branch portion of the third hot water supply passage is equal to or higher than a predetermined temperature, the hot water flowing through the third hot water supply passage passes through the first branch supply passage. When the temperature of the warm water returned to the tank and flowing through the branch portion of the third warm water feed channel is lower than a set temperature, the warm water flowing through the third warm water feed channel passes through the second branch feed channel. The hot water is supplied to the hot water circulation path.

  Further, in the fuel cell exhaust heat utilization system according to claim 3 of the present invention, in addition to the configuration according to claim 1 or 2, the heat consuming device is a desiccant air conditioner.

  According to the exhaust heat utilization system for a fuel cell according to claim 1 of the present invention, a fuel cell that generates electricity and heat and a solar heat collector that heats using solar heat are used in combination. The hot water heated using the exhaust heat is further heated by a solar heat collector as necessary to increase the temperature. A hot water circulation channel for circulating water in the hot water storage tank, a first hot water supply channel for feeding water from the hot water circulation channel to the solar heat collector, and solar heat for heating by the solar heat collector A second hot water supply passage for supplying hot water heated by the heat collector to the hot water storage tank, and a third hot water for supplying hot water heated by the solar heat collector toward the heat consuming device. A supply flow path and a consumed hot water circulation path for circulating hot water through the heat consuming device are provided.

  When the water in the hot water tank is heated using a solar heat collector, the water in the hot water tank flows through the hot water circulation path and the first heat exchanger. In the first heat exchanger, the fuel cell is Heat is exchanged with the cooling water for cooling, and then is supplied to the solar heat collector through the first hot water supply passage, and is heated by the solar heat collector and then passed through the second hot water supply passage. The hot water returned to the hot water tank and heated by the solar heat collector after being heated by the first heat exchanger in this way is supplied to the hot water tank to increase the hot water storage temperature of the hot water tank. Can do.

  Further, when the solar heat collector is used for heating and consumption by the heat consuming device, the water in the hot water storage tank flows through the hot water storage circulation path and the first heat exchanger, and the fuel in the first heat exchanger. Heat is exchanged with cooling water for cooling the battery, then supplied to the solar heat collector through the first hot water supply passage, and heated by the solar heat collector, and then the third hot water supply flow Heat was exchanged with the hot water in the consumption hot water circulation flow path in the second heat exchanger, heated in the first heat exchanger in this way, and further heated in the solar heat collector. The hot water is supplied toward the heat consuming device, and the temperature of the hot water that exchanges heat with the hot water of the heat consuming device can be increased.

  According to the exhaust heat utilization system for a fuel cell according to claim 2 of the present invention, the downstream side of the third hot water supply passage is branched into the first and second branch supply passages, and the third hot water is supplied. When the temperature of the hot water flowing through the branch portion of the feed flow path is equal to or higher than the predetermined temperature, the hot water flowing through the third hot water feed flow path is returned to the hot water storage tank through the first branch feed flow path. Excess heat after heat consumption can be stored as hot water in a hot water tank. In addition, when the temperature of the hot water flowing through the branch portion of the third hot water supply passage is lower than the set temperature, the hot water flowing through the third hot water supply passage is sent to the hot water circulation passage through the second branch supply passage. Since this hot water is heated, it is heated by exchanging heat with the cooling water in the first heat exchanger, and further heated by the solar heat collector and consumed as a heat consuming device. Become.

  According to the exhaust heat utilization system for a fuel cell according to claim 3 of the present invention, the heat consuming device is a desiccant air conditioner, and the water in the hot water tank is exchanged with the cooling water of the fuel cell. By further heating the heated water with a solar heat collector, it can be heated to about 80 ° C. hot water, and the desiccant air conditioner can be operated efficiently.

  Hereinafter, an exhaust heat utilization system for a fuel cell according to the present invention will be described with reference to the accompanying drawings. FIG. 1 is a system diagram schematically illustrating an exhaust heat utilization system according to an embodiment, and FIG. 2 is a diagram illustrating a flow of hot water when the exhaust heat utilization system of FIG. 1 is operated in a water supply heat storage mode. 3 is a diagram showing the flow of hot water when the exhaust heat utilization system of FIG. 1 is operated in the hot water storage heat storage mode, and FIG. 4 is an operation of the exhaust heat utilization system of FIG. 1 in the desiccant air conditioning mode. FIG. 5 is a diagram showing the flow of hot water when returning the hot water to the hot water circulation circuit, and FIG. 5 shows the flow of hot water when the exhaust heat utilization system of FIG. 1 is operated in the desiccant air conditioning mode and hot water is stored in the hot water tank. FIG. 6 is a diagram illustrating a flow of hot water when the exhaust heat utilization system of FIG. 1 is operated in the floor heating mode.

  In FIG. 1, the exhaust heat utilization system of a fuel cell shown in FIG. 1 includes a polymer electrolyte fuel cell 2 as a fuel cell, a hot water storage tank 4 for storing hot water, and water (or hot water) using solar heat. And a solar heat collecting device 6 for heating. The polymer electrolyte fuel cell 2 generates electricity and heat by a fuel cell reaction, and the solar heat collector 6 collects and heats the heat from sunlight, and exhausts heat from the fuel cell 2 and / or solar heat collection. Hot water heated by the heat collection of the device 6 is stored in the hot water storage tank 4, and exhaust heat and / or heat collection is stored in the hot water storage tank 4 as hot water. Moreover, in this embodiment, it is comprised so that the waste heat of the fuel cell 2 and / or the heat collection of the solar thermal collector 6 may be consumed by the desiccant air conditioner 8 and the floor heater 10 as heat consuming equipment. For example, a bathroom heater / dryer may be employed as the heat consuming device.

  The polymer electrolyte fuel cell 2 is provided with a cooling water circulation channel 12, and cooling water for cooling the polymer electrolyte fuel cell 2 is circulated through the cooling water circulation channel 12. The hot water storage tank 4 is provided with a hot water storage water circulation channel 14, and the water in the hot water storage tank 4 is circulated through the hot water storage water circulation channel 14. A first heat exchanger 16 is provided in association with the cooling water circulation channel 12 and the hot water circulation channel 14, and in this first heat exchanger 16, the cooling water and the hot water circulation channel 14 flowing through the cooling water circulation channel 12. Heat is exchanged with the water flowing through the water, and the water in the hot water circulation channel 14 is heated by this heat exchange.

  The hot water storage circulation path 14 is provided with a feed pump 18 on the upstream side of the first heat exchanger 16, and the water in the hot water tank 4 circulates through the hot water storage circulation path 14 by the action of the feed pump 18. Is done. Further, a three-way switching valve 20 is provided on the downstream side of the first heat exchanger 16, a first connection portion of the three-way switching valve 20 is connected to the first heat exchanger 16 side, and the second connection portion is solar heat. It is connected to the heat collecting device 6 side, and its third connecting portion is connected to the hot water tank 4 side. Since the three-way switching valve 20 is in the first switching state, the three-way switching valve 20 communicates the first heat exchanger 16 side and the hot water tank 4 side, and allows hot water from the first heat exchanger 16 to flow. When guided to the hot water tank 4 and in the second switching state, the first heat exchanger 16 side and the solar heat collector 6 side are communicated, and the hot water from the first heat exchanger 16 is solar heat collected as will be described later. Guide to device 6.

  The solar heat collecting device 6 is connected to the second connecting portion of the three-way switching valve 20 via the first hot water supply passage 22 and is connected to the hot water storage tank 4 via the second hot water supply passage 24. . Moreover, the 1st consumption hot water supply flow path 26 (comprising the 3rd hot water supply flow path) for supplying the hot water from the solar heat collecting device 6 toward the desiccant air conditioner 8 as a heat consuming apparatus; And a second consumption hot water supply passage 28 (which constitutes a third hot water supply passage) for supplying hot water from the solar heat collector 6 toward the floor heating device 10 as a heat consuming device. In this embodiment, the upstream side portions of the first and second consumed hot water feed passages 26, 28 are connected to the second hot water feed passage 24, and the second consumed hot water feed passage 28 The downstream side portion is connected to the first consumed hot water supply passage 26. Further, the downstream side of the first consumption hot water supply passage 26 is branched into two, the first branch supply passage 30 is connected to the hot water tank 4, and the second branch supply passage 32 is a hot water circulation passage. 14 (specifically, upstream of the first heat exchanger 16).

  In this embodiment, the first on-off valve 34 is provided in the second hot water supply passage 24 (specifically, a portion downstream of the connection portion of the first and second consumed hot water supply passages 26, 28). The second on-off valve 36 is disposed in the first consumed hot water feed passage 26, and the third on-off valve 38 is disposed in the second consumed hot water feed passage 28. In addition, a fourth open / close valve 40 is disposed in the first branch supply flow path 30, and a fifth open / close valve 42 is disposed in the second branch supply flow path 32. Accordingly, when the first on-off valve 34 is in the open state and the second and third on-off valves 36 and 38 are in the closed state, the hot water from the solar heat collecting device 6 is supplied to the hot water storage tank 4, but the second on-off valve When the valve 36 is in the open state and the first and third on-off valves 34 and 38 are in the closed state, the hot water from the solar heat collecting device 6 is supplied to the first consumed hot water supply passage 26 and the third open / close is opened. When the valve 38 is open and the first and second on-off valves 34 and 36 are closed, the hot water from the solar heat collecting device 6 is supplied to the second consumed hot water supply passage 28. Furthermore, when the fourth on-off valve 40 is in the open state and the fifth on-off valve 42 is in the closed state, the hot water from the first consumption hot water supply passage 26 is sent to the hot water tank 4 through the first branch supply passage 30. When the fourth open / close valve 40 is closed and the fifth open / close valve 42 is open, the hot water from the first consumption hot water supply flow path 26 flows through the second branch supply flow path 32 to circulate hot water storage water. Sent to the road 14.

  The heat of the hot water flowing through the first consumption hot water supply passage 26 is configured to be consumed by the desiccant air conditioner 8. The desiccant air conditioner 8 is a publicly known air conditioner including a desiccant wheel, a sensible heat exchanger, an evaporative cooler, a heater, and the like. The desiccant cycle dehumidifies and cools the outside air and introduces it into the room. Heat the room air, humidify it, and discharge it outdoors. In this desiccant cycle, the desiccant is regenerated (dried) in the desiccant wheel. The regeneration of the desiccant requires a temperature of about 80 ° C., and the air discharged from the room to the room is heated to about 80 ° C. The heat of the hot water flowing through the first consumption hot water supply passage 26 is used for this heating.

  The desiccant air conditioner 8 is provided with an air-conditioning hot water circulation channel 44 (which constitutes a consumed hot water circulation channel), and hot water for heating air used for regeneration of the desiccant is used for the air-conditioning hot water circulation channel 44. Circulated through. A first consumed heat exchanger 46 (which constitutes a second heat exchanger) is provided in association with the first consumed hot water supply passage 26 and the first consumed hot water circulation passage 44, and this first consumed heat exchanger. In 46, heat exchange is performed between the hot water flowing through the first consumed hot water supply channel 26 and the hot water flowing through the first consumed hot water circulation channel 44, and the first consumed hot water circulation channel 44 is exchanged by this heat exchange. Of warm water.

  Moreover, the heat of the hot water flowing through the second consumption hot water supply passage 28 is configured to be consumed by the floor heating device 10. The floor heating device 10 is a publicly known device including a heat radiating panel having a built-in heat radiating tube, a uniform heat-uniforming sheet from the heat radiating tube, a finishing member to be a floor surface, and the like. Thus, the floor surface is heated, the indoor space is heated from the floor surface, and the heat of the hot water flowing through the second consumed hot water supply passage 28 is used to warm the hot water flowing through the heat radiating tube.

  The floor heating device 10 is provided with a hot water circulation channel 48 for floor heating (which constitutes a hot water circulation channel for consumption), and hot water flowing through the heat radiating tube for heating the floor passes through the hot water circulation channel 48 for floor heating. Circulated. A second consumed heat exchanger 50 (which constitutes a second heat exchanger) is provided in association with the second consumed hot water supply passage 28 and the second consumed hot water circulation passage 48, and this second consumed heat exchanger. 50, heat exchange is performed between the hot water flowing through the second consumed hot water supply passage 28 and the hot water flowing through the second consumed hot water circulation passage 48, and the second consumed hot water circulation passage 48 is obtained by this heat exchange. Of warm water.

  The exhaust heat utilization system further includes a control device 52 for controlling the system and an operation device 54 for setting the operation mode of the system. In this embodiment, the operation device 54 is configured to be able to set the operation in the water supply heat storage mode, the first hot water tank heat storage mode, the second hot water tank heat storage mode, the desiccant air conditioning mode, and the floor heating mode. The control means 52 controls the operation of the fuel cell 2, the solar heat collector 6, the feed pump 18, the three-way switching valve 20, and the first to fifth on-off valves 34 to 42. The operation of the desiccant air conditioner 8 is controlled by, for example, a dedicated air conditioning remote controller (not shown), and the floor heating apparatus 10 is controlled by, for example, a dedicated floor heating remote controller (not shown).

Next, with reference to FIGS. 2 to 6 together with FIG. 1, the operation state in various operation modes of the above-described fuel cell exhaust heat utilization system will be described.
When the water supply / heat storage mode is set by the operation device 54, the operation state shown in FIG. The solar heat collector 6 is connected to a water supply source (not shown) such as a water pipe via a water supply valve (not shown). In this water supply heat storage mode, the water supply valve is opened. The first on-off valve 34 is opened, and the solar heat collecting device 6 is operated. In such a state, water from the water supply source is supplied to the solar heat collector 6 and heated to a predetermined temperature (for example, about 80 ° C.) by the solar heat collector 6 and thus heated. The heated hot water flows into the hot water storage tank 4 through the second hot water supply passage 24, and the hot water raised to a predetermined temperature by the solar heat collecting device 6 is stored in the hot water storage tank 4, thereby increasing the amount of heat stored in the hot water storage tank 4. can do. At this time, the fuel cell 2, the desiccant air conditioner 8, the floor heating device 10, and the feed pump 18 are not operated, and the second to fifth on-off valves 36 to 42 are kept closed.

  Moreover, when the first hot water storage tank heat storage mode is set by the operation device 54, the operation state shown in FIG. The fuel cell 2, the solar heat collector 6 and the feed pump 18 are operated, the three-way switching valve 20 is held in the second switching state, and the first on-off valve 34 is opened. In such a state, electricity is generated by the fuel cell reaction of the polymer electrolyte fuel cell 2, and cooling water for cooling the fuel cell 2 is circulated through the cooling water circulation passage 12. In addition, the water in the hot water tank 4 is circulated through the hot water circulation channel 14 by the action of the feed pump 18, and the hot water flowing in the cooling water circulation channel 12 and the water flowing in the hot water circulation channel 14 in the first heat exchanger 16. The hot water heated by this heat exchange (for example, heated to about 60 ° C.) passes through the three-way switching valve 20 and passes through the first hot water supply passage 22 to collect solar heat. It is fed to the device 6. The solar heat collector 6 further heats the hot water heated by the first heat exchanger 16 to rise to a predetermined temperature (for example, about 80 ° C.), and the heated hot water is supplied to the hot water storage tank 4. The amount of heat stored in the hot water storage tank 4 can be increased. At this time, the desiccant air conditioner 8 and the floor heater 10 do not operate, and the second to fifth on-off valves 36 to 42 are kept closed.

  Further, when the desiccant air-conditioning mode is set by the operation device 54, the operation state shown in FIG. 4 (or FIG. 5) is obtained. The fuel cell 2, the solar heat collector 6, the feed pump 18 and the desiccant air conditioner 8 are operated, the three-way switching valve 20 is maintained in the second switching state, and the second and fifth on-off valves 36, 42 (or The second and fourth on-off valves 36, 40) are opened. In such a state, as described above, the polymer electrolyte fuel cell 2 generates electric power, and the cooling water for cooling the fuel cell 2 is circulated through the cooling water circulation passage 12 and also in the hot water tank 4. Is circulated through the hot water circulation channel 14, and heat exchange is performed between the hot water in the cooling water circulation channel 12 and the water in the hot water circulation channel 14 in the first heat exchanger 16. The heated water (for example, heated to about 60 ° C.) is supplied to the solar heat collector 6 through the three-way switching valve 20 and the first hot water supply passage 22. The solar heat collecting device 6 further heats the warm water heated by the first heat exchanger 16 to rise to a predetermined temperature (for example, about 80 ° C.), and the warm water thus heated is the first consumed hot water. Hot water for heating air for regenerating a desiccant wheel (not shown) of the desiccant air conditioner 8 is circulated through the first consumption hot water circulation channel 44 and supplied to the supply channel 26. In the one consumption heat exchanger 46, heat exchange is performed between the hot water in the first consumption hot water supply passage 26 and the hot water in the first consumption hot water circulation passage 44, and the desiccant air conditioning is performed by the hot water heated by the heat exchange. The regeneration air of the device 8 is heated. The polymer electrolyte fuel cell 2 has a low operating temperature of the fuel cell reaction, and can generate only hot water of about 60 ° C. even if the heat of the cooling water is used. This hot water is generated by the solar heat collector 6. By further heating, the water can be heated to about 80 ° C., which can be used for heating the regeneration air of the desiccant air conditioner 8, and the desiccant of the exhaust heat of the polymer electrolyte fuel cell 2. Application to the air conditioner 8 becomes possible.

  The temperature of the hot water in the first consumed hot water supply passage 26 after the heat exchange of the first consumed heat exchanger 46 is a set temperature (for example, about 55 ° C., and the first heat exchanger 16 is connected to the cooling water. 4, the fifth on-off valve 42 is opened, and the hot water from the first consumed hot water supply passage 26 is in the second branch, as shown in FIG. The hot water is supplied to the hot water circulating flow path 14 through the supply flow path 32, and after being heat exchanged with the cooling water of the fuel cell 2 in the first heat exchanger 16, the heat is again supplied to the solar heat collecting device 6. It is circulated through the 1 heat exchanger 16, the three-way switching valve 20, the solar heat collector 6, and the first consumption heat exchanger 46. At this time, the floor heating device 10 does not operate, and the first, third, and fourth on-off valves 34, 38, 40 are kept closed.

  On the other hand, when the temperature of the hot water in the first consumed hot water supply passage 26 after the heat exchange of the first consumed heat exchanger 46 exceeds the set temperature, as shown in FIG. The hot water from the first consumption hot water supply passage 26 is supplied to the hot water tank 4 through the first branch supply passage 30. In this case, even if the hot water is returned to the hot water circulation passage 14 and flows through the first heat exchanger 16, heat exchange with the cooling water is not performed in the first heat exchanger. The amount of heat is stored in the hot water storage tank 4, and the amount of stored heat increases. At this time, the floor heating apparatus 10 does not operate, and the first, third, and fifth on-off valves 34, 38, 42 are kept closed.

  Further, when the floor heating mode is set by the operation device 54, the operation state shown in FIG. 6 is obtained. The fuel cell 2, the solar heat collecting device 6, the feed pump 18 and the floor heating device 10 are operated, the three-way switching valve 20 is held in the second switching state, and the third and fifth on-off valves 38, 42 (or The third and fourth on-off valves 38, 40) are opened. In this floor heating mode, hot water from the solar heat collector 6 flows through the second consumed hot water supply passage 28 and hot water flowing through a heat radiating tube (not shown) of the floor heating device 10 is circulated in the second consumed hot water circulation. The heat is exchanged between the hot water in the second consumed hot water supply flow path 28 and the hot water in the second consumed hot water circulation flow path 48 in the second consumed heat exchanger 50 by circulation through the flow path 46. Heating is performed using the heat of the warmed water, and even during this heating, the hot water is heated to about 80 ° C. by the solar heat collector 6, so that heating can be performed efficiently.

  Even during the heating, when the temperature of the hot water in the second consumed hot water supply passage 28 after the heat exchange of the second consumed heat exchanger 48 is equal to or lower than a set temperature (for example, about 55 ° C.), a solid line in FIG. As shown in FIG. 5, the fifth on-off valve 42 is opened, and the hot water from the second consumption hot water supply passage 28 is supplied to the hot water circulation passage 14 through the second branch supply passage 32, and the first After the heat exchange with the cooling water of the fuel cell 2 in the heat exchanger 16, the heat is again fed to the solar heat collecting device 6, but the second consumed hot water is fed after the heat exchange of the second consumed heat exchanger 50. When the temperature of the hot water in the supply passage 28 exceeds the set temperature, the fourth on-off valve 40 is opened as shown by the broken line in FIG. 5, and the hot water from the second consumed hot water supply passage 28 is opened. Is fed to the hot water tank 4 through the first branch feed channel 30.

  Further, when the second hot water storage tank heat storage mode is set by the operation device 54, the fuel cell 2 and the feed pump 18 are operated, and the three-way switching valve 20 is held in the first switching state. In this operating state, the polymer electrolyte fuel cell 2 generates electricity, its cooling water is circulated through the cooling water circulation passage 12, and the water in the hot water tank 4 is circulated through the hot water circulation flow by the action of the feed pump 18. Heat is exchanged between the hot water in the cooling water circulation passage 12 and the water in the hot water circulation passage 14 in the first heat exchanger 16 and is heated through the heat exchange (for example, Is heated to about 60 ° C.) through the three-way switching valve 20 and fed to the hot water tank 4. At this time, the solar heat collector 6, the desiccant air conditioner 8, and the floor heater 10 do not operate, and the first to fifth on-off valves 34 to 42 are held closed.

  As mentioned above, although one embodiment of the exhaust heat utilization system of the fuel cell according to the present invention has been described, the present invention is not limited to such an embodiment, and various modifications or corrections can be made without departing from the scope of the present invention. Is possible.

  For example, in the illustrated embodiment, the desiccant air conditioner 8 and the floor heating device 10 are used as heat consuming equipment, but only one of these may be used, or in addition to these, a bathroom heating dryer. May be used.

  The fuel cell waste heat utilization system of the present invention uses a combination of a fuel cell and a solar heat collector, and supplies hot water heated using the waste heat of the fuel cell to the solar heat collector for further heating. The temperature is raised to, for example, about 80 ° C. For example, a polymer electrolyte fuel cell as a fuel cell has a low operating temperature of the fuel cell reaction and can only heat water up to about 60 ° C. using the exhaust heat. By combining them, the hot water can be raised to about 80 ° C. Thus, by raising the temperature of the hot water in this way, it can be applied to a desiccant air conditioner as a heat consuming device. When applied to a floor heating device, a bathroom heating dryer, etc., the heating efficiency can be increased. Thus, even when a polymer electrolyte fuel cell is used as a household fuel cell, the temperature of the hot water used can be increased to broaden the application of the heat consuming device, and the energy utilization rate can be increased.

It is a system diagram showing the exhaust heat utilization system of one embodiment simply. FIG. 2 is a diagram illustrating a flow of hot water when the exhaust heat utilization system of FIG. 1 is operated in the water supply heat storage mode. It is a figure which shows the flow of warm water when the waste heat utilization system of FIG. 1 is drive | operated in hot water storage tank thermal storage mode. It is a figure which shows the flow of warm water when operating the exhaust-heat utilization system of FIG. 1 in desiccant air-conditioning mode, and returning warm water to the hot water storage water circulation flow path. It is a figure which shows the flow of warm water when operating the exhaust-heat utilization system of FIG. 1 in desiccant air-conditioning mode, and storing warm water in a hot water storage tank. It is a figure which shows the flow of warm water when driving the exhaust-heat utilization system of FIG. 1 in floor heating mode.

Explanation of symbols

2 Solid Polymer Fuel Cell 4 Hot Water Storage Tank 6 Solar Heat Collector 8 Desiccant Air Conditioner 10 Floor Heater 12 Cooling Water Circulation Channel 14 Hot Water Tank Circulation Channel 16, 46, 50 Heat Exchanger 18 Feed Pump 20 Three-way Switching Valve 22, 24, 26, 28 Hot water supply flow path 30, 32 Branched supply flow path 34, 36, 38, 40, 42 On-off valve 44, 48 Consumption hot water circulation flow path 52 Control device 54 Operation operation device

Claims (3)

A fuel cell that generates electricity and heat, a hot water tank for storing heat as hot water, a solar heat collector for heating water using solar heat, a heat consuming device that consumes heat, and the fuel A cooling water circulation channel for circulating cooling water through the battery, a hot water circulation channel for circulating water in the hot water tank, and a first hot water supply for supplying water flowing through the hot water circulation channel to the solar heat collector A supply channel, a second hot water supply channel for supplying hot water from the solar heat collector to the hot water storage tank, and a second hot water supply channel for supplying hot water from the solar heat collector toward the heat consuming device. 3. Heat exchange is performed between the hot water supply flow path, the consumed hot water circulation path that circulates hot water through the heat consuming device, the cooling water that flows through the cooling water circulation path, and the water that flows through the hot water storage circulation path. A first heat exchanger, and hot water flowing through the third hot water supply passage Anda second heat exchanger for exchanging heat between the hot water flowing in the consumption hot-water circulation passage,
When the water in the hot water tank is heated using the solar heat collecting device, the water in the hot water tank flows through the hot water circulation path and the first heat exchanger, and the first heat exchanger. Heat exchanged with the cooling water circulating through the cooling water circulation flow path, and then fed through the first hot water feed flow path to the solar heat collecting device and heated by the solar heat collecting device. Returned to the hot water storage tank through the second hot water supply passage,
When the solar heat collecting device is used for heating and consumption by the heat consuming device, the water in the hot water storage tank flows through the hot water storage water circulation channel and the first heat exchanger, and In one heat exchanger, heat is exchanged with the cooling water circulating through the cooling water circulation flow path, and then supplied to the solar heat collecting apparatus through the first hot water supply flow path, and is added by the solar heat collecting apparatus. Use of exhaust heat of a fuel cell, wherein the fuel cell is heated after flowing through the third hot water supply passage and is exchanged with the hot water flowing through the consumed hot water circulation passage in the second heat exchanger system.   The downstream side of the third hot water feed channel is branched into first and second branch feed channels, the first branch feed channel is connected to the hot water storage tank, and the second branch feed channel Is connected to the upstream side of the first heat exchanger of the hot water circulation passage, and when the temperature of the hot water flowing through the branch portion of the third hot water supply passage is equal to or higher than a predetermined temperature, the third hot water The hot water flowing through the feed channel is returned to the hot water tank through the first branch feed channel, and when the temperature of the hot water flowing through the branch of the third hot water feed channel is lower than a set temperature, the first 2. The exhaust heat utilization system for a fuel cell according to claim 1, wherein the hot water flowing through the three hot water supply passage is supplied to the hot water circulation passage through the second branch supply passage.   The exhaust heat utilization system for a fuel cell according to claim 1 or 2, wherein the heat consuming device is a desiccant air conditioner.

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