Combined Heat and Power System

Abstract

This cogeneration system includes a fuel battery, a heat supply channel, and a first heat exchange unit. The fuel battery is formed by accommodating fuel battery cells. The heat supply channel causes a medium to flow, the medium recovering heat generated from the fuel battery. The first heat exchange unit is positioned near the outer side of the fuel battery, or positioned inside thereof, and causes the medium flowing in the heat supply channel to recover heat generated by the fuel battery.

Description

[Technical field]

[0001] TECHNICAL FIELD This disclosure relates to combined heat and power systems. [Background technology]

[0002] 2. Description of the Related Art There is known a domestic cogeneration system that generates electricity using a fuel cell, recovers heat discharged from the fuel cell, and uses the recovered heat to heat and supply city water (see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2002-298863 A Summary of the Invention [Problem to be solved by the invention]

[0004] In cogeneration systems using fuel cells, it is difficult to provide the required amount of heat for the hot water supplied using only the recovered heat, and it has been necessary to install a water heater to further heat the hot water.

[0005] Therefore, an object of the present disclosure, made in consideration of the above-mentioned problems of the conventional technology, is to provide a cogeneration system capable of providing more required heat to a medium. [Means for solving the problem]

[0006] In one embodiment, (1) a cogeneration system includes a fuel cell, a heat supply path through which a medium for recovering heat generated by the fuel cell flows, and a first heat exchange section located adjacent to the outside of the fuel cell or inside the fuel cell, which causes the medium circulating through the waste heat recovery path to recover heat generated by the fuel cell.

[0007] (2) The cogeneration system according to (1) above further includes a second heat exchange unit that exchanges heat between the exhaust gas from the fuel cell and the medium flowing through the heat supply path.

[0008] (3) In the cogeneration system according to (2) above, in the heat supply path, the first heat exchange unit is located downstream of the second heat exchange unit.

[0009] (4) In the cogeneration system according to (2) or (3) above, the heat supply path has a branch path that is located downstream of the first heat exchange section and includes a heat dissipation section.

[0010] (5) In the cogeneration system according to (4) above, the branch passage is further connected to the heat supply passage on the upstream side of the second heat exchange unit.

[0011] (6) In the cogeneration system according to (4) or (5) above, the heat dissipation section is located in a discharge path for the exhaust gas of the second heat exchange section.

[0012] (7) In the combined heat and power supply system described in any one of (1) to (6) above, the fuel cell further comprises a housing and a reformer housed in the housing, and a flow path of the medium in the first heat exchanger is provided inside the housing or outside the housing in close proximity to the housing.

[0013] (8) The cogeneration system according to (7) above further includes a heat insulating mechanism that suppresses heat transfer from at least one of the reformer and the fuel cell to the flow path in the first heat exchanger.

[0014] (9) In the cogeneration system according to (7) above, the flow path of the first heat exchanger is capable of contacting the outside of the housing.

[0015] (10) In the heat and power cogeneration system described in any one of (1) to (9) above, the fuel cell comprises a storage section in which the fuel cell cells are arranged, an exhaust gas flow path through which exhaust gas discharged from the fuel cell cells flows, and an insulating material arranged in contact with the exhaust gas flow path and separating the storage section from the exhaust gas flow path, and the heat supply path in the first heat exchange section is provided inside the fuel cell in contact with the exhaust gas flow path, and at least a portion of the heat supply path is embedded in the insulating material.

[0016] (11) In the cogeneration system described in (10) above, the exhaust gas flow path has a drain section on a downstream side for discharging moisture contained in the exhaust gas, and has an exhaust section on an upstream side of the drain section for discharging exhaust gas contained in the exhaust gas.

[0017] (12) The cogeneration system described in (11) above has an oxygen-containing gas flow path, adjacent to the exhaust gas flow path, through which an oxygen-containing gas supplied to the fuel cell flows, and an inlet portion connected to the oxygen-containing gas flow path is located between the drain portion and the exhaust portion.

[0018] (13) In the cogeneration system according to any one of (10) to (12) above, a combustion catalyst is disposed inside the storage unit or upstream of the heat exchange unit in the exhaust gas flow path.

[0019] (14) The heat and power cogeneration system described in any one of (10) to (13) above includes a control device that controls the fuel cell to reduce a fuel utilization rate or increase an air utilization rate when a medium is flowed through the first heat exchange section. Effect of the Invention

[0020] According to the cogeneration system according to the present disclosure configured as described above, the required heat can be efficiently provided to the medium. [Brief description of the drawings]

[0021] [Figure 1]1 is a schematic configuration diagram of a cogeneration system according to a first embodiment. [Diagram 2] 2 is a structural diagram that shows a schematic internal configuration of the fuel cell in FIG. 1 when the heat insulating mechanism is in a closed state. [Diagram 3] 1. FIG. 4 is a structural diagram that illustrates a modified example of the internal configuration of the fuel cell in FIG. 1 when the heat insulating mechanism is in a closed state. [Figure 4] 2 is a structural diagram that shows a schematic internal configuration of the fuel cell in FIG. 1 when the heat insulating mechanism is in an open state. [Diagram 5] 2 is a structural diagram showing an outline of the internal configuration of a modified example of the fuel cell in FIG. [Figure 6] 1 is a perspective view of a housing of a fuel cell in a combined heat and power supply system according to an embodiment of the present invention when a medium flows through a pipeline. FIG. [Figure 7] 13 is a perspective view of a modified example of a housing of a fuel cell in the cogeneration system of the present embodiment. FIG. [Figure 8] 1 is a perspective view of a housing of a fuel cell in a combined heat and power supply system according to an embodiment of the present invention when no medium flows through the pipelines. FIG. [Figure 9] FIG. 5 is a schematic configuration diagram of a cogeneration system according to a second embodiment. [Figure 10] FIG. 11 is a schematic configuration diagram of a cogeneration system according to a third embodiment. [Figure 11] FIG. 11 is a schematic diagram of a fuel cell according to a fourth embodiment. [Figure 12] FIG. 13 is a diagram showing another example of the configuration of the fuel cell according to the fourth embodiment. [Figure 13] FIG. 11 is a schematic configuration diagram of a cogeneration system according to a fourth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] Hereinafter, an embodiment of a cogeneration system to which the present disclosure is applied will be described with reference to the drawings. In each drawing, the same or corresponding parts are given the same reference numerals. In the following description of the embodiment, the description of the same or corresponding parts will be omitted or simplified as appropriate. Also, the drawings are schematic. The dimensional ratios and the like in the drawings do not necessarily correspond to the actual ones.

[0023] 1, a cogeneration system 100 according to a first embodiment of the present disclosure includes a fuel cell 15, a heat supply path 18, and a first heat exchange unit 19. The cogeneration system 100 is installed in, for example, a home. The cogeneration system 100 may further include a second heat exchange unit 20 and a heat insulating mechanism described below.

[0024] The fuel cell 15 generates power using raw fuel gas, air, and water. The fuel cell 15 generates heat during operation to generate power. The heat generated by the fuel cell 15 is recovered using a medium. The heat supply path 18 supplies heat to the area in which the heat supply path 18 is arranged by causing the medium to flow.

[0025] The fuel cell 15 may have at least one of a reformer and a cell stack (fuel cell). The fuel cell 15 may be a fuel cell module that includes the reformer and the cell stack in a housing. The reformer generates fuel such as hydrogen by causing a steam reforming reaction between gas supplied as raw fuel and water. The cell stack is, for example, a solid oxide fuel cell (SOFC), and generates power by an electrochemical reaction using an oxidant such as oxygen contained in the air and a fuel generated by the reformer. The cell stack also generates water by an electrochemical reaction. Unreacted fuel and unreacted oxidant discharged from the cell stack are combusted to provide energy for a steam reforming reaction in the reformer. The water discharged from the cell stack is discharged from the fuel cell 15 in a high-temperature gaseous state together with combustion gas resulting from the combustion of the unreacted fuel and unreacted oxidant. The cell stack may be a polymer electrolyte fuel cell (PEFC). In this case, other configurations may be any appropriate configuration.

[0026] The exhaust gas discharged from the fuel cell 15 may contain combustion gas and gaseous water. The exhaust gas discharged from the fuel cell 15 may be heat exchanged with a medium using a second heat exchanger 20 described below. The exhaust gas cooled by the heat exchange may be separated into gaseous exhaust gas and condensed liquid water by a gas-liquid separator 23. The separated exhaust gas may be discharged outside the cogeneration system 100. The separated water may be sent to the fuel cell 15 as water to be used in the steam reforming reaction.

[0027] The heat supply path 18 recovers heat by flowing a medium through the first heat exchange section 19. The heat supply path 18 may recover heat by flowing a medium through the second heat exchange section 20. The medium is, for example, a fluid with a large specific heat, such as water.

[0028] The first heat exchange unit 19 causes the medium flowing through the heat supply path 18 to recover heat generated from the fuel cell 15. As shown in Fig. 2, the first heat exchange unit 19 recovers heat by transferring heat from its outer surface to the medium flowing through the heat supply path 18 when the medium flows through a pipe (medium flow path) 25.

[0029] The first heat exchanger 19 may be located close to the outside of the fuel cell 15 (housing) or inside (inside the housing). When the first heat exchanger 19 is located close to the outside of the fuel cell 15, it may be located so as to be in contact with the outside of the fuel cell 15, or may be located without contacting the fuel cell within a range in which it can receive heat from the fuel cell. When the first heat exchanger 19 is located inside the fuel cell 15, it may be located around at least one of the reformer and the cell stack without an insulating material. For example, as shown in FIGS. 2 to 5, the first heat exchanger 19 may be formed by providing a pipe 25 through which a medium flowing through the heat supply path 18 passes, around at least one of the reformer 26 and the cell stack 27. In this case, the pipe 25 may be provided around at least one of the reformer 26 and the cell stack 27 without an insulating material. In the present disclosure, the heat insulating material is a material that prevents heat transfer, and may be, for example, a fiber-based heat insulating material such as glass wool, or a foam-based heat insulating material such as resin foam. Therefore, in the present disclosure, the heat shielding mechanism 31 and the housing 29 described later are not included in the heat insulating material. Note that, without the intermediation of a heat insulating material means that no material having heat insulating properties is located on a straight line that connects at least a part of the surface of the duct 25 and at least one surface of the reformer 26 and the cell stack 27 in the shortest distance. Therefore, even if the packing 28 made of a material having heat insulating properties is located closer to the reformer 26 or the cell stack 27 than the duct 25, it can function as the first heat exchanger 19.

[0030] A housing 29 may be provided to house at least one of the reformer 26 and the cell stack 27. The housing 29 may be made of metal. For example, the housing 29 may cover three sides of the reformer 26 and the cell stack 27. As shown in Fig. 5, the medium pipe 25 in the first heat exchange section 19 may be located close to the outside of the housing 29 within a range that allows heat transfer from at least one of the reformer 26 and the cell stack 27.

[0031] 6, the conduit 25 may have a zigzag shape that extends horizontally on the longer side of the housing 29 and turns back on the shorter side. Therefore, the conduit 25 may extend long on the outer surface of the housing 29. The inlet and outlet of the conduit 25 on the outer surface of the housing 29 may be oriented in the horizontal direction.

[0032] As shown in Fig. 7, the duct 25 may be provided in a housing 29. More specifically, the housing 29 may be manufactured by pressing two plates so that the duct 25 is formed between the plates. The inlet and outlet of the duct 25 from inside the housing 29 may face downward. The shape of the duct 25 may be a zigzag shape that extends horizontally inside the long side of the housing 29 and turns back inside the short side. In a configuration in which the duct 25 is provided in the housing 29, a heat insulating material 30 may be located between the duct 25 and the housing 29 as shown in Figs. 2 and 3.

[0033] As shown in FIG. 2 to FIG. 4, the heat and power cogeneration system 100 may have heat shielding mechanisms 31a and 31b. As shown in FIG. 2 to FIG. 4, the heat shielding mechanism 31a may have at least one heat shielding plate 31s. The heat shielding mechanism 31a has, for example, a plurality of heat shielding plates 31s. The heat shielding plate 31s may be rectangular. The heat shielding plate 31s may be supported so as to be rotatable about one side of the rectangle. The heat shielding plate 31s may be switchable between a closed state and an open state. In other words, the heat shielding mechanism 31a is a blind-shaped member. In the closed state, the heat shielding plate 31s may block communication between the pipe 25 and the reformer 26 or the cell stack 27. In the open state, the heat shielding plate 31s may open communication between the pipe 25 and the reformer 26 or the cell stack 27.

[0034] The heat insulation mechanism 31a controls radiant heat from at least one of the reformer 26 and the cell stack 27 to the pipe 25 in the first heat exchange section 19. More specifically, as shown in Fig. 2, the heat insulation mechanism 31a in the closed state blocks part of the radiation from the reformer 26 or the cell stack 27 and part of the convection of the surrounding gas. Only the convection that bypasses the heat insulation mechanism 31a may reach the pipe 25. As shown in Fig. 4, the heat insulation mechanism 31a in the open state allows the convection of the surrounding gas from the reformer 26 or the cell stack 27 to pass through and blocks part of the radiation from the reformer 26 or the cell stack 27.

[0035] The heat shield mechanism 31a may include a closing plate 31c as shown in FIG. 3 at least one of above the highest position of the duct 25 and below the lowest position. When the heat shield 31s is in the closed state, the closing plate 31c closes at least one of the vertical directions in the space between the heat shield 31s and the duct 25. In this case, the closing plate 31c closes at least one of the vertical directions in the space between the heat shield 31s and the duct 25, thereby stopping or weakening the flow of high-temperature gas. The closing plate 31c may include multiple plates that are supported rotatably, similar to the heat shield 31s, and may be switchable between a closed state and an open state. The closing plate 31c may be a single plate.

[0036] 5, the heat shield mechanism 31b may be configured by positioning the pipe 25 outside the housing 29. The pipe 25 as the flow path of the first heat exchange section 19 can be in contact with the outside of the housing 29.

[0037] More specifically, the pipe 25 is attached to a plate-shaped movable member 32m. The movable member 32m may move in parallel to move away from or toward the housing 29. The movable member 32m in contact with the housing 29 is shown by a solid line, and the movable member 32m separated from the housing 29 is shown by a dotted line. The housing 29 is heated to, for example, about 400 to 600°C by radiation from the reformer 26 or the cell stack 27 or convection of exhaust gas. When the movable member 32m is in contact with the housing 29, the pipe 25 attached to the movable member 32m is heated more strongly. On the other hand, when the movable member 32m is separated from the housing 29, the heating of the pipe 25 is weakened.

[0038] The operation of the heat insulating mechanism for adjusting the heat transfer may be realized by a motor. The operation of the heat insulating mechanism may be realized by a bimetal made of plates with different thermal expansion coefficients bonded together. The operation of the heat insulating mechanism may be realized by a thermoelement containing wax. The operation of the heat insulating mechanism is, for example, switching the state of the heat insulating mechanism 31a or displacing the movable member 32m.

[0039] The operation of the heat shielding mechanism may be realized by the pressure of the elastic member and the heat medium. A specific example of a heat shielding mechanism that can be operated based on the pressure of the elastic member and the heat medium will be described below. With reference to FIG. 6 and FIG. 8, the pipe 25 may include a first portion 25n, a second portion 25w, and a spring (elastic body) 32e. The first portion 25n may be fixed to the housing 29, or may be located without contacting the housing 29 within a range in which the first portion 25n can receive heat from the fuel cell. The second portion 25w may extend horizontally on the longitudinal surface of the housing 29. The first portion 25n and the second portion 25w may be cylindrical. The diameter of the first portion 25n may be smaller than the diameter of the second portion 25w. Or, the diameter of the first portion 25n may be larger than the diameter of the second portion 25w. One of the first portion 25n and the second portion 25w may be connected to the other of the first portion 25n and the second portion 25w in a state in which the other of the first portion 25n and the second portion 25w is inserted inside the housing 29 so as to be slidable along the axial direction on the short side of the housing 29. The spring 32e may be provided to bias the second portion 25w toward the first portion 25n. The spring 32e may be wound around the first portion 25n.

[0040] When the spring 32e is contracted, the second portion 25w may be in contact with the longitudinal surface of the housing 29 directly or via a movable member described later. When the spring 32e is contracted, the second portion 25w may be close to the longitudinal surface of the housing 29 within a range in which the second portion 25w can receive heat from the fuel cell 16. On the other hand, when the spring 32e is expanded, the second portion 25w may be separated from the longitudinal surface of the housing 29.

[0041] The conduit 25 is subjected to the static pressure of the medium in the conduit 25. The static pressure exerts a force in a direction that expands the spring 32e. Thus, in response to an increase in the static pressure, the medium applies a force to the second portion 25w so as to expand the spring 32e. When the static pressure is decreasing, the force applied by the medium to the conduit 25 becomes weaker. The force of the medium to move the second portion 25w of the conduit 25 away from the first portion 25n may also become weaker. Thus, the spring 32e may contract, and the second portion 25w may be closer to the longitudinal surface of the housing 29. On the other hand, when the static pressure is increasing, the force of the medium to move the second portion 25w of the conduit 25 away from the first portion 25n may also become stronger. Thus, the spring 32e may expand, and the second portion 25w may be separated from the longitudinal surface of the housing 29.

[0042] The pipe 25 may be fixed to the movable member 32m, which is a connecting plate facing the longitudinal surface of the housing 29. With this configuration, it is possible to prevent an excessive load from being applied to the pipe 25. An elastic body may be provided between the movable member 32m and the housing 29. Furthermore, a part of the pipe 25 may be an elastic body. With this configuration, by opening the hot water outlet valve 33, the elastic body of the pipe 25 may contract, and the pipe 25 may come into contact with the longitudinal surface of the housing 29. Furthermore, by opening the hot water outlet valve 33, the elastic body of the pipe 25 may contract, and the pipe 25 may come close to the longitudinal surface of the housing 29 within a range in which the pipe 25 can receive heat from the fuel cell 16. Furthermore, by closing the hot water outlet valve 33, the elastic body of the pipe 25 may expand, and the pipe 25 may be separated from the longitudinal surface of the housing 29.

[0043] For the fuel cell 15 to generate electricity, it is required that the temperatures of the reformer 26 and the cell stack 27 are maintained within an ideal temperature range. When the first heat exchanger 19 having the above-mentioned configuration is used, the reformer 26 and the cell stack 27 are cooled by the heat medium. Therefore, the fuel cell 15 generates not only the amount of heat required for power generation but also the amount of heat for heating the heat medium. In this configuration, when the supply of the medium is stopped, the reformer 26 and the cell stack 27 are cooled by the heat exchange in the first heat exchanger 19 even though the heating of the heat medium is not required. On the other hand, since the heat insulating mechanism can adjust the amount of heat exchanged in the first heat exchanger 19, when the heating of the heat medium is not required, the cooling of the reformer 26 and the cell stack 27 can be suppressed. Therefore, by using the heat insulating mechanism, when the heating of the heat medium is not required, the supply amount of the raw fuel gas supplied to the fuel cell 15 can be reduced, and the power generation efficiency can be increased.

[0044] As shown in FIG. 1, the second heat exchange unit 20 is, for example, a heat exchanger. The second heat exchange unit 20 exchanges heat between the exhaust gas discharged from the fuel cell 15 and a medium flowing through the heat supply path 18. The second heat exchange unit 20 may be located upstream of the first heat exchange unit 19 in the heat supply path 18. The exhaust gas discharged from the fuel cell 15 is generally lower in temperature (for example, about 200 to 300° C.) than the ambient temperature of the reformer 26 and the cell stack 27. Therefore, the second heat exchange unit 20 functions as a preheater of the medium for the first heat exchange unit 19.

[0045] The heat supply path 18 is, for example, a hot water supply path. A first flow rate control valve 43 for adjusting the supply amount of the medium may be provided on the upstream side of the second heat exchange section 20 in the heat supply path 18. A hot water outlet valve 33 may be provided on the downstream side of the first heat exchange section 19 in the heat supply path 18. The pressure of the medium may be adjusted higher at the upstream end of the heat supply path 18 than at the downstream end. For example, the upstream end of the heat supply path 18 may be connected to a high-pressure clean water pipe. The hot water outlet valve 33 opens to allow the medium to flow downstream. In addition, when the hot water outlet valve 33 is open, the static pressure of the medium in the pipe 25 on the upstream side of the hot water outlet valve 33 decreases. When the hot water outlet valve 33 is closed, the static pressure of the medium in the pipe 25 on the upstream side of the hot water outlet valve 33 decreases compared to when it is open. Therefore, the static pressure of the medium in the pipe 25 may be adjusted by opening and closing the tap valve 33. The above-mentioned heat shielding mechanism may be operated by adjusting the static pressure of the medium in the pipe 25. More specifically, when the tap valve 33 is open, the spring 32e may contract and the second portion 25w may be close to the longitudinal surface of the housing 29, as shown in FIG. 6. When the tap valve 33 is closed, the spring 32e may expand and the pipe 25 may be separated from the longitudinal surface of the housing 29, as shown in FIG. 8.

[0046] The heat supply path 18 may branch into a low-temperature delivery path 34 between the first flow rate control valve 43 and the second heat exchanger 20. The low-temperature delivery path 34 may bypass the second heat exchanger and the first heat exchanger. The low-temperature delivery path 34 may be provided with a second flow rate control valve 45 that adjusts the amount of medium supplied. The temperature of the medium delivered from the heat supply path 18 can be adjusted by adjusting the flow rate of the medium bypassed to the low-temperature delivery path 34 by the second flow rate control valve 45. By mixing the low-temperature medium flowing in the low-temperature delivery path 34 with the high-temperature medium flowing in the heat supply path 18, a medium that is lower in temperature than the heat supply path 18 can be delivered.

[0047] More specifically, the heat supply path 18 heats drinking water supplied from outside the facility in which the combined heat and power supply system 100 is installed by flowing it through a heat exchange section such as the first heat exchange section 19, and supplies hot water to a consumer facility, for example.

[0048] 9, a cogeneration system 200 according to a second embodiment of the present disclosure has a configuration similar to that of the cogeneration system 100. Hereinafter, the same configuration as that of the cogeneration system 100 will not be described again, and only the configuration different from that of the cogeneration system 100 will be described.

[0049] The heat supply path 18 branches downstream of the fuel cell 15 into a hot water outlet path 18a and a circulation path 18b.

[0050] The circulation path 18b may be provided with a heat dissipation unit 13. The heat dissipation unit 13 is, for example, a radiator, and dissipates heat from the medium by exchanging heat between the air supplied by a blower and the medium.

[0051] A pump 24 may be provided downstream of the heat radiating section 13. The pump 24 may increase the pressure of the medium so that the medium flows from the heat radiating section 13 toward the second heat exchange section 20.

[0052] Downstream of the pump 24 may be located the second heat exchange section 20. Downstream of the second heat exchange section 20 may be located the first heat exchange section 19.

[0053] 10, a cogeneration system 300 according to a third embodiment of the present disclosure has a configuration similar to that of the cogeneration system 200. Hereinafter, the same configuration as that of the cogeneration system 200 will not be described again, and only the configuration different from that of the cogeneration system 200 will be described.

[0054] The circulation path 18b may be provided with a heat dissipation section 14. The heat dissipation section 14 is, for example, a radiator. The heat dissipation section 14 is located in the exhaust gas discharge path of the second heat exchange section 20. More specifically, the heat dissipation section 14 is located downstream of the gas-liquid separator 23 in the exhaust gas discharge path of the second heat exchange section 20.

[0055] A pump 21 may be provided downstream of the heat dissipation unit 14. The circulation path 18b may merge with the heat supply path 18 downstream of the pump 21. The pump 21 may increase the pressure of the medium so that the medium flows from the heat dissipation unit 14 toward the second heat exchange unit 20.

[0056] The cogeneration systems 100, 200, and 300 of the present embodiment, which are configured as described above, have a first heat exchanger 19 located close to the outside of the fuel cell 15 or inside the fuel cell 15, and which recovers heat generated from the fuel cell 15 to a medium flowing through the heat supply path 18. In a cogeneration system using a general fuel cell, waste heat is recovered by heat exchange between the exhaust gas of the fuel cell and the medium, but it is difficult to heat the medium sufficiently and to temporarily supply a large amount of hot water. In a cogeneration system that recovers waste heat from exhaust gas and is difficult to temporarily supply a large amount of heat, a water heater must be provided to meet the request to temporarily supply a large amount of heat. On the other hand, the cogeneration systems 100, 200, and 300 of the present embodiment, which have the above-mentioned configuration, can recover a large amount of heat compared to a configuration in which waste heat is recovered from exhaust gas, because the fuel cell 15 itself generally operates at a higher temperature than the exhaust gas. Therefore, the cogeneration systems 100, 200, and 300 can temporarily supply a large amount of hot water. Therefore, since the cogeneration systems 100, 200, and 300 can temporarily supply a large amount of hot water, it is not necessary to install a water heater. Therefore, the cogeneration systems 100, 200, and 300 can be made compact.

[0057] Moreover, the cogeneration systems 100, 200, and 300 of the present embodiment have a second heat exchange unit 20 that exchanges heat between the exhaust gas of the fuel cell 15 and a medium flowing through the heat supply path 18. With this configuration, the cogeneration systems 100, 200, and 300 can lower the temperature of the exhaust gas of the fuel cell 15.

[0058] In the heat supply path 18 of the cogeneration systems 100, 200, and 300 of the present embodiment, the first heat exchange unit 19 is located downstream of the second heat exchange unit 20. With this configuration, the medium flows into the first heat exchange unit 19, which recovers heat generated from the fuel cell 15, after being heated in the second heat exchange unit 20. This prevents the low-temperature medium from removing a large amount of heat from the fuel cell 15. This allows the power generation efficiency of the fuel cell 15 to be maintained.

[0059] Moreover, the heat supply path 18 of the cogeneration systems 200 and 300 of the present embodiment has a circulation path 18b as a branch path located downstream of the first heat exchanger 19 and including the heat dissipation sections 13 and 14. With this configuration, the cogeneration systems 200 and 300 can cool the heat accumulated in the medium when hot water is not being supplied. Therefore, the cogeneration systems 200 and 300 can prevent an extreme decrease in the amount of water recovered from the exhaust gas.

[0060] Moreover, the heat dissipation section 14 of the heat supply path 18 of the cogeneration system 300 of this embodiment is located in the exhaust path of the exhaust gas of the second heat exchange section 20. With this configuration, a blower or the like for cooling the heat dissipation section 14 is not required, and the configuration can be simplified and manufacturing costs can be reduced.

[0061] Moreover, the fuel cell 15 of the heat and power cogeneration systems 100, 200, and 300 of the present embodiment further includes a housing 29 and at least one of the reformer 26 and the cell stack 27 housed in the housing 29, and the flow path of the medium in the first heat exchange unit 19 is provided inside the housing 29 or outside the housing 29 in close proximity to the housing 29. With this configuration, the medium can be close to the high-temperature region of the housing 29 or its periphery in the first heat exchange unit 19. Therefore, the medium can be heated more efficiently in the first heat exchange unit 19.

[0062] Moreover, the cogeneration systems 100, 200, and 300 of the present embodiment have a heat insulating mechanism 31 that suppresses heat transfer from at least one of the reformer 26 and the cell stack 27 to the pipe 25 serving as a flow path in the first heat exchange section 19. With this configuration, excessive heating of the pipe 25 can be suppressed.

[0063] Moreover, the pipe 25 as the flow path of the first heat exchange unit 19 of the cogeneration systems 100, 200, and 300 of the present embodiment can be in contact with the outside of the housing 29. With this configuration, the pipe 25 is located outside the housing 29, and the pipe 25 and therefore the medium can be heated more strongly.

[0064] FIG. 11 is a schematic diagram showing the configuration of a fuel cell applied to a cogeneration system according to a fourth embodiment.

[0065] The fuel cell 416 of the cogeneration system generates electricity using fuel cell units 490 (cell stack), and uses the generated heat to increase the temperature of a medium.

[0066] The fuel cell 416 includes a fuel cell 490, a storage section 429, an exhaust gas flow path 495, and a heat insulating material 430. The fuel cell 416 also has an oxygen-containing gas flow path 494. The fuel cell 416 may also include a reformer 426.

[0067] The fuel cell 490 is disposed in the storage section 429 of the fuel cell 416. In this embodiment, the fuel cell 416 includes the reformer 426 and the fuel cell 490 in the storage section 429. The storage section 429 may be included in the housing 431. Specifically, the storage section 429 may be a part of the inner wall of the housing 431 and a part of the heat insulating material 430 described later. The part of the inner wall of the housing 431 and the part of the heat insulating material may define the internal space of the storage section 429. More specifically, the metal housing 431 may define a part of the boundary of the storage section 429. For example, the housing 431 may define the remaining three sides (sides not adjacent to the exhaust gas flow path 495) of the storage section 429 having a rectangular cross section. The heat insulating material 430 may define another part of the boundary of the storage section 429. For example, the heat insulating material 430 may define one side of the cross section of the storage section 429. The reformer 426 generates fuel such as hydrogen by causing a steam reforming reaction between gas supplied as a raw fuel and water. The fuel cell 490 is, for example, a solid oxide fuel cell (SOFC), and generates power by an electrochemical reaction using an oxidant such as oxygen contained in the air and a fuel generated by the reformer 426. The fuel cell 416 generates heat during operation for generating power. The fuel cell 490 also generates water by an electrochemical reaction. Unreacted fuel and unreacted oxidant discharged from the fuel cell 490 are combusted to provide energy for causing a steam reforming reaction in the reformer 426. The water discharged from the fuel cell 490 is discharged from the fuel cell 416 in a high-temperature gaseous state together with combustion gas resulting from the combustion of the unreacted fuel and unreacted oxidant. The heat generated during operation for generating power and the heat of combustion are recovered using a medium as heat generated by the fuel cell 416. Here, the fuel cell 490 may be a polymer electrolyte fuel cell (PEFC).

[0068] In the fuel cell 416, exhaust gas discharged from the fuel cell 490 flows through an exhaust gas flow path 495 and is discharged. The exhaust gas contains at least one of fuel gas not used for power generation, combustion gas (exhaust gas, gas) obtained by burning the fuel gas discharged from the fuel cell 490, and gaseous water. In the fuel cell 416, a heat insulating material 430 is disposed in contact with the exhaust gas flow path 495, and separates the storage section 429 from the exhaust gas flow path 495. The heat insulating material 430 is a material that prevents heat transfer, and may be, for example, a fiber-based heat insulating material such as glass wool, or a foam-based heat insulating material such as a resin foam.

[0069] The exhaust gas flow passage 495 has a drain section 493 that discharges moisture contained in the exhaust gas on the downstream side. The exhaust gas flow passage 495 also has an exhaust section 491 that discharges exhaust gas contained in the exhaust gas on the upstream side of the drain section 493. The oxygen-containing gas flow passage 494 is provided adjacent to the exhaust gas flow passage 495, and an oxygen-containing gas supplied to the fuel cell 490 flows through the oxygen-containing gas flow passage 494. An inlet section 492 connected to the oxygen-containing gas flow passage 494 is located between the drain section 493 and the exhaust section 491. The exhaust gas flowing through the exhaust gas flow passage 495 is cooled by the oxygen-containing gas in the adjacent oxygen-containing gas flow passage 494. Of the cooled exhaust gas, liquid water (drain) in which moisture has condensed is discharged from the drain section 493, and gas is discharged from the exhaust section 491. The separated water discharged from the drain section 493 may be sent to the fuel cell 416 as water to be used for the steam reforming reaction in the reformer 426. With this configuration of the fuel cell 416, water to be used in the steam reforming reaction can be separated from the exhaust gas without providing a gas-liquid separator, so that the overall system can be made compact. In other words, the gas-liquid separator 23 can be omitted in Figures 1, 9, and 10.

[0070] The exhaust gas is cooled by heat exchange with the oxygen-containing gas in the oxygen-containing gas flow passage 494. Meanwhile, the oxygen-containing gas is heated by heat exchange with the exhaust gas. The heated oxygen-containing gas flows into the reformer 426 and the fuel cell 490, so that the cooling of the reformer 426 and the fuel cell 490 can be reduced. Therefore, the temperatures of the fuel cell 490 and the reformer 426 can be kept high. Therefore, the power generation efficiency of the fuel cell 490 and the reformer 426 can be maintained.

[0071] The heat supply path 425 is located inside the fuel cell 416 (inside the storage section 429). In this embodiment, the heat supply path 425 is provided in contact with the exhaust gas flow path 495, and is configured so that a medium flows inside. At least a part of the heat supply path 425 is embedded in the heat insulating material 430. At least a part of the heat supply path 425 may be exposed to the exhaust gas flow path 495. As shown in FIG. 11, in this embodiment, the heat supply path 425 is configured by being embedded in the heat insulating material 430. The heat supply path 425 provided in contact with the exhaust gas flow path 495 and the exhaust gas flow path 495 constitutes a first heat exchange section 419 corresponding to the first heat exchange section 19 described in the first to third embodiments. With such a configuration of the fuel cell 416, the medium can efficiently collect heat generated by the fuel cell 416 inside the storage section 429, which is at high temperature, and therefore, effective use of heat is possible.

[0072] Here, a combustion catalyst 496 may be used to promote the combustion of exhaust gas. In the fuel cell 416 according to this embodiment, the combustion catalyst 496 is disposed inside the storage section 429 or upstream of the heat supply path 425 in the exhaust gas flow path 495. Here, as another example, the fuel cell 416 may be configured not to use the combustion catalyst 496. When the combustion catalyst 496 is not used, it is preferable to configure the fuel cell 416 so that the amount of air is sufficient by making the combustion distance L between the combustion part and the reformer 426 large, as shown in FIG. 12.

[0073] As shown in FIG. 13, a cogeneration system 400 according to an embodiment of the present disclosure includes the above-mentioned fuel cell 416. The cogeneration system 400 is a hot water supply system. That is, in the fuel cell 416, the medium flowing through the heat supply path 425 is water, which is supplied as hot water. For example, the cogeneration system 400 may have a heating system. In this case, the medium that has flowed through the heat supply path 425 may circulate through the heating system, and the medium may be water or an antifreeze solution. That is, the medium flowing through the heat supply path 425 may be supplied directly or indirectly to a user.

[0074] The cogeneration system 400 includes a fuel cell 416 including a plurality of flow paths through which water flows, a heat supply path 425, and a control device 435. The cogeneration system 400 may include a cooling / heating device 422. The cogeneration system 400 is installed in, for example, a home.

[0075] The cogeneration system 400 according to this embodiment has an external water flow path 81, a hot water supply flow path 412, a heat exchange flow path 482, and a water flow path 484 as a plurality of flow paths through which water flows.

[0076] The external water flow path 481 is a flow path through which water supplied from outside the cogeneration system 400 flows. A temperature sensor 455 for measuring the temperature of the water that has entered the external water flow path 481 may be provided. Also, a flow rate sensor 462 for measuring the amount of water that has entered the external water flow path 481 may be provided. The external water flow path 481 may be provided with a first flow rate adjustment valve 443 for adjusting the amount of water supplied.

[0077] The hot water supply flow path 412 is a flow path that supplies heated water (hot water) to the outside. A temperature sensor 456 that measures the temperature of the water at the outlet of the hot water supply flow path 412 may be provided.

[0078] The heat exchange passage 482 connects the external water passage 481 and the hot water supply passage 412 , and passes through the heat supply passage 425 .

[0079] The water flow path 484 is another flow path that connects the external water flow path 481 and the hot water supply flow path 412. The water flow path 484 may be provided with a second flow rate adjustment valve 446 that adjusts the amount of water passing through the water flow path 484.

[0080] In the cogeneration system 400, water from the hot water supply passage 412 may circulate through the water passage 484 into the external water passage 481. A circulation pump 440 may be provided in the external water passage 481 to boost the pressure of the water so as to circulate it.

[0081] The cooling / heating device 422 is provided near the hot water supply flow path 412, and heats or cools the water flowing through the hot water supply flow path 412. The cooling / heating device 422 may be, for example, a burner, an electric heater, or the like. The cooling / heating device 422 may be, for example, a burner, and may have a fuel injection line for supplying gas fuel, and an air supply line for forcibly drawing in outside air with a blower and supplying it. The cooling / heating device 422 mixes gas fuel and outside air at an ignition port and burns them. The water is heated by the combustion of the cooling / heating device 422. The cooling / heating device 422 can also cool the water by generating wind with a blower. The temperature of the hot water supplied to the outside can be further appropriately adjusted by the cooling / heating device 422.

[0082] The control device 435 includes one or more processors and a memory. The processor may include a general-purpose processor that loads a specific program to execute a specific function and a dedicated processor specialized for a specific process. The dedicated processor may include an application specific integrated circuit (ASIC). The processor may include a programmable logic device (PLD). The PLD may include a field-programmable gate array (FPGA). The control device 35 may be either a system-on-a-chip (SoC) or a system in a package (SiP) in which one or more processors work together. The control device 435 may control components of the cogeneration system 400, such as the circulation pump 440, the first flow rate control valve 443, the second flow rate control valve 446, and the cooling and heating device 422. In this embodiment, the control device 435 also controls the operation of the fuel cell 416.

[0083] The control device 435 controls the components of the cogeneration system 400 including the fuel cell 416 in response to a request for hot water supply. For example, when there is a continuous request for hot water supply, the control device 435 controls the first flow rate control valve 443 and the second flow rate control valve 446 to flow a medium (water) through the heat supply path 425. At this time, the control device 435 controls the fuel cell 416 to decrease the fuel utilization rate or increase the air utilization rate. Specifically, the control device 435 may increase the fuel supply rate to decrease the fuel utilization rate and burn the fuel that remains unconsumed in the fuel cell 416. This control makes it difficult for the temperature inside the fuel cell 416 to decrease, so that heat is effectively utilized.

[0084] The fuel cell 416 and the combined heat and power system 400 according to this embodiment can utilize heat effectively and be made compact by the above-mentioned configuration. Therefore, the fuel cell 416 and the combined heat and power system 400 according to this embodiment are suitable for a home cogeneration system that requires compactness and size reduction.

[0085] The drawings for explaining the embodiments according to the present disclosure are schematic, and the dimensional ratios and the like in the drawings do not necessarily correspond to the actual ones.

[0086] Although the embodiments of the present disclosure have been described based on the drawings and examples, it should be noted that those skilled in the art can make various modifications or alterations based on the present disclosure. Therefore, it should be noted that these modifications or alterations are included in the scope of the present disclosure. For example, the functions, etc. included in each component, etc. can be rearranged so as not to cause logical inconsistencies, and multiple components, etc. can be combined into one or divided.

[0087] All of the features described in this disclosure and / or all steps of any method or process disclosed herein may be combined in any combination except those combinations in which the features are mutually exclusive. Furthermore, each feature described in this disclosure may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly denied. Thus, unless expressly denied, each disclosed feature is merely one example of a generic series of the same or equivalent features.

[0088] Furthermore, the embodiments of the present disclosure are not limited to any of the specific configurations of the embodiments described above, but rather extend to any novel feature or combination of features described herein, or any novel method or process step or combination of features described herein.

[0089] In this disclosure, descriptions such as "first" and "second" are identifiers for distinguishing the configuration. In the configurations distinguished by descriptions such as "first" and "second" in this disclosure, the numbers in the configurations can be exchanged. For example, the first heat exchange unit can exchange the identifiers "first" and "second" with the second heat exchange unit. The exchange of identifiers is performed simultaneously. The configurations remain distinguished even after the identifiers are exchanged. The identifiers may be deleted. A configuration from which an identifier has been deleted is distinguished by a symbol. The descriptions of identifiers such as "first" and "second" in this disclosure should not be used solely to interpret the order of the configurations or to justify the existence of an identifier with a smaller number.

[0090] Furthermore, the embodiments of the present disclosure are not limited to any of the specific configurations of the above-described embodiments, and can extend to any novel feature or combination of features described in the present disclosure. [Explanation of symbols]

[0091] 100,200,300,400 Combined Heat and Power System 13,14 Heat dissipation part 15,416 Fuel cells 18 Heat supply path 18a Hot water outlet 18b Circulation path 19,419 First heat exchange section 20 Second heat exchange section 21,24 Pump 23 Gas-liquid separator 25,425 pipes 25n First Part 25w 2nd part 26,426 Reformer 27 Cell Stack 28 Packing 29 Case 30 Insulation 31a, 31b Heat shielding mechanism 32m moving parts 33 Hot water valve 34 Low temperature delivery path 43 First flow control valve 45 Second flow control valve 412 Hot water supply flow path 422 Cooling and heating equipment 429 Storage section 430 Insulation 431 Case 435 Control Device 440 Circulation Pump 443 First flow control valve 446 Second flow control valve 455 Temperature Sensor 456 Temperature Sensor 462 Flow Sensor 481 External water channel 482 Heat exchange channel 484 Water channel 490 Fuel Cell 491 Discharge section 492 Introduction 493 Drain 494 Oxygen-containing gas flow path 495 Exhaust gas flow path 496 Combustion Catalyst

Claims

1. A fuel cell comprising a solid oxide fuel cell unit and a reformer housed in a housing; a heat supply path through which a medium for recovering heat generated from the fuel cell flows; a first heat exchange unit that causes the medium to recover heat generated in the fuel cell; a hot water outlet valve located on the heat supply path so that the medium flowing through the heat supply path is directly outlet to the outside, A flow path of the medium in the first heat exchange unit is provided inside the housing or outside the housing in close proximity to the housing, Combined heat and power systems.

2. 2. The combined heat and power system according to claim 1, a second heat exchange unit for exchanging heat between the exhaust gas of the fuel cell and the medium flowing through the heat supply path. Combined heat and power systems.

3. 3. The combined heat and power system according to claim 2, In the heat supply path, the first heat exchange portion is located downstream of the second heat exchange portion. Combined heat and power systems.

4. 4. The heat and power cogeneration system according to claim 2 or 3, The heat supply path has a branch path that is located downstream of the first heat exchange portion and includes a heat dissipation portion. Combined heat and power systems.

5. 5. The combined heat and power system according to claim 4, The branch passage is further connected to the upstream side of the second heat exchange section in the heat supply passage. Combined heat and power systems.

6. 5. The combined heat and power system according to claim 4, The heat radiating portion is located in a discharge path of the exhaust gas of the second heat exchange portion. Combined heat and power systems.

7. In the combined heat and power supply system according to any one of claims 1 to 3, a heat insulating mechanism that suppresses heat transfer from at least one of the reformer and the fuel cell to the flow path in the first heat exchanger. Combined heat and power systems.

8. In the combined heat and power supply system according to any one of claims 1 to 3, The flow path of the first heat exchanger is capable of contacting the outside of the housing. Combined heat and power systems.

9. In the combined heat and power supply system according to any one of claims 1 to 3, The fuel cell includes a storage section in which the fuel cell cells are arranged, an exhaust gas flow path through which exhaust gas discharged from the fuel cell flows, and a heat insulating material arranged in contact with the exhaust gas flow path and separating the storage section from the exhaust gas flow path, and the heat supply path in the first heat exchanger is provided in contact with the exhaust gas flow path inside the fuel cell, and at least a portion of the heat supply path is embedded in the heat insulating material. Combined heat and power systems.

10. 10. The combined heat and power system according to claim 9, The exhaust gas flow path has a drain section on a downstream side for discharging moisture contained in the exhaust gas, and has a discharge section on an upstream side of the drain section for discharging exhaust gas contained in the exhaust gas.

11. 11. The combined heat and power system according to claim 10, a combined heat and power supply system having an oxygen-containing gas flow path adjacent to the exhaust gas flow path, through which an oxygen-containing gas supplied to the fuel cell flows, and an inlet portion connected to the oxygen-containing gas flow path is located between the drain portion and the exhaust portion.

12. 10. The combined heat and power system according to claim 9, A combined heat and power supply system, wherein a combustion catalyst is disposed inside the storage unit or upstream of the heat exchange unit in the exhaust gas flow path.

13. The heat and power supply system according to claim 1, The heat supply path is located outside or inside the housing, and extends along the horizontal direction on the longitudinal surface and is folded back. Combined heat and power systems.

14. In the combined heat and power supply system according to any one of claims 1 to 3, A cogeneration system comprising a control device that controls the fuel cell so as to reduce a fuel utilization rate or increase an air utilization rate when a medium is caused to flow through the first heat exchange section.

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