Hot water storage system

Abstract

To provide a hot water storage system enabling both of a self-supporting power generation function in the case of emergency and a water taking-out function in the case of emergency.SOLUTION: A hot water storage system 1 includes: a hot water storage tank (4) storing hot water; and a fuel cell power generating device (3) cooled by water taken out from a lower part of the hot water storage tank (4). The hot water storage system also includes: an emergency water taking-out plug (57) for taking out hot water in the hot water storage tank (4) in the case of emergency; a water taking-out pipe (56) for taking out hot water from an intermediate stage part in the height direction of the hot water storage tank (4) or a part in the vicinity of the intermediate stage part; and an air charge part (58) capable of introducing air to the hot water storage tank (4). The emergency water taking-out plug (57) is connected to the water taking-out pipe (56).SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] This invention relates to a hot water storage system having a fuel cell, and in particular to a hot water storage system that can perform power generation and water supply functions even in emergencies (power outages and water outages). [Background technology]

[0002] 2. Description of the Related Art A hot water storage system is known that includes a hot water storage tank and a fuel cell unit, in which water taken from the bottom of the hot water storage tank is used to cool the fuel cell unit and the generated hot water is returned to the top of the hot water storage tank. 6 shows a typical hot water storage system including a hot water storage tank 70 and a fuel cell unit 71. A drain pipe 72 is connected to the bottom of the hot water storage tank 70 for draining the water used to fill the tank when the hot water storage system is installed, and a drain plug 73 is provided on the drain pipe 72.

[0003] A tank outlet pipe 74 is provided from the top of the hot water storage tank 70, and an air charge pipe 75 is connected to this tank outlet pipe 74, and an air charge valve 76 is provided on the air charge pipe 75. A circulation supply passage 77 extending from the bottom of the hot water storage tank is connected to the fuel cell unit 71, and a circulation return passage 78 extending from the fuel cell unit 71 is connected to the top of the hot water storage tank 70. A bypass passage 79 and a three-way valve 80 connecting the circulation supply passage 77 and the circulation return passage 78 are also provided.

[0004] Techniques for extracting hot water from the hot water storage system via a drain pipe and drain plug during a water outage are well known, as are techniques for utilizing electricity generated by the fuel cell during a power outage.

[0005] On the other hand, the hot water storage system described in Patent Document 1 is configured to be able to supply hot water by heating water taken out of a hot water storage tank with an electric heater provided in the fuel cell when gas supply is stopped. In the heat storage system described in Patent Document 2, medium-temperature water is taken out from a pipe connected to the heat storage tank near the middle stage and used. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent Publication No. 2016-38114 [Patent Document 2] Patent Publication No. 2005-147494 Summary of the Invention [Problem to be solved by the invention]

[0007] The hot water storage system, which includes a hot water storage tank and a fuel cell unit, has two resilience features. The independent power generation function during power outages allows power generation to continue as long as there is water (cooling water) in the hot water storage tank, even if the water supply is cut off during a power outage.In addition, the emergency water extraction function allows hot water or water to be extracted from the hot water storage tank and used for domestic water in the event of a water outage.

[0008] However, if the water in the hot water storage tank is removed, the cooling water will be lost and power generation will no longer be possible, so it is not possible to achieve both the above-mentioned independent power generation function and the emergency water extraction function at the same time.

[0009] An object of the present invention is to provide a hot water storage system that can achieve both an independent power generation function in an emergency and a water extraction function in an emergency. [Means for solving the problem]

[0010] The hot water storage system of claim 1 is a hot water storage system including a hot water storage tank for storing hot water and a power generation device cooled by water taken out from the bottom of the hot water storage tank, and further including an emergency water outlet valve for taking out hot water from the hot water storage tank in an emergency, a water outlet pipe for taking out hot water from the middle part of the hot water storage tank in the height direction or a part in the vicinity thereof, and an air charge part capable of introducing air into the hot water storage tank. a connecting passage connecting the top of the hot water storage tank with a middle portion of the hot water storage tank in the height direction or a portion thereof in the vicinity thereof; Equipped with the water outlet pipe is provided so as to branch off from the lower end portion of the connecting passage, An emergency water outlet valve is connected to the water outlet pipe.

[0011] According to the above configuration, in an emergency (power outage or water outage), independent power generation is possible as long as there is water (cooling water) in the hot water storage tank, and hot water or water in the hot water storage tank can be extracted via the water extraction pipe and emergency water extraction valve and used as water for daily use. Since the water extraction pipe is intended to extract hot water from the middle of the hot water storage tank or its surrounding area, it is not possible to extract water (cooling water) from the lower half of the hot water storage tank, and the system can maintain its independent power generation function until the water temperature rises.

[0012] Also, According to the above configuration, the water extraction pipe is connected to the hot water storage tank via the connecting passage, which is advantageous in terms of manufacturing since the number of pipe welding points to the hot water storage tank can be reduced.

[0013] Claim 2 The hot water storage system is 1 of The invention is characterized by having a drain pipe connected to the lower end of the hot water storage tank and a drain plug provided at the lower end of the drain pipe. According to the above configuration, the drain pipe and drain plug can be used to drain the water filled in the hot water storage tank and piping system from the hot water storage tank during trial operation at the time of installation of the hot water storage system. [Effects of the Invention]

[0014] As described above, the present invention provides various effects. [Brief explanation of the drawings]

[0015] [Figure 1] 1 is a configuration diagram of a hot water storage system according to an embodiment of the present invention. [Figure 2] FIG. 2 is a configuration diagram of a fuel cell unit. [Figure 3] FIG. 2 is a diagram showing the detailed structure of the hot water storage tank (full state). [Figure 4] This is a diagram showing the detailed structure of the hot water storage tank (in an emergency hot water extraction state). [Figure 5]FIG. 5 is a view corresponding to FIG. 4 according to a modified example. [Figure 6] FIG. 4 is a view corresponding to FIG. 3 according to the prior art. DETAILED DESCRIPTION OF THE INVENTION

[0016] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to the accompanying drawings. First, the overall configuration of the hot water storage system 1 of the present invention will be described. As shown in Figure 1, the hot water storage system 1 is composed of a hot water storage and heating device 2 that stores hot water, a fuel cell power generation device 3 that generates electricity, and an exhaust heat recovery circulation circuit 15 that circulates hot water between the hot water storage and heating device 2 and the fuel cell power generation device 3 to recover exhaust heat from the exhaust gas of the fuel cell power generation device 3.

[0017] Next, the hot water storage and heating apparatus 2 will be briefly described. As shown in Figure 3, the hot water storage and heating system 2 has functions such as storing hot water, supplying hot water, supplying hot water to a bathtub, reheating the bathtub, and supplying hot water to hot water heating devices such as floor heating panels, and includes a hot water storage tank 4, an auxiliary heat source unit 5, a bath heat utilization heat exchanger 6, a heating heat utilization heat exchanger 7, a water supply system passage 8, a hot water supply system passage 9, a hot water outlet passage 11, a bath reheating circuit 12, a hot water heating circuit 13, a heat utilization circulation circuit 14, an exhaust heat recovery circulation circuit 15, a control unit 10, and an operation remote control 20 for setting various settings for the hot water storage and heating system, most of which are housed together in an exterior case 16. An outside air temperature detection sensor 16a capable of detecting the outside air temperature is installed in the exterior case 16.

[0018] Next, the hot water tank 4 will be described. The hot water storage tank 4 is composed of a sealed tank capable of storing high-temperature hot water (for example, 60 to 70°C) heated by the fuel cell power generation system 3, and the tank is surrounded by a heat insulating material to prevent the stored hot water from losing heat. A plurality of hot water temperature detection sensors 4a to 4d are provided in order at equal intervals from the bottom to the top around the outer periphery of the hot water storage tank 4, and these multiple hot water temperature detection sensors 4a to 4d detect the hot water temperatures of the multiple temperature stratifications inside the hot water storage tank 4.

[0019] Next, the auxiliary heat source unit 5 will be described. The auxiliary heat source unit 5 is configured as a known gas water heater incorporating a burner, a heat exchanger, and the like. The auxiliary heat source unit 5 is activated to burn and heat the hot water only in special cases, such as when the temperature of the hot water in the hot water storage tank 4 drops or when the supply of hot water to the hot water storage tank is stopped, when a command is sent from the control unit 45.

[0020] Next, the water supply passage 8 will be described. The water supply system passage 8 supplies low-temperature clean water from a clean water source to the hot water storage tank 4 and the like, and has an upstream water supply passage section 8a, an intermediate water supply passage section 8b, and a downstream water supply passage section 8c, with the upstream end of the upstream water supply passage section 8a connected to the clean water source and the downstream end of the downstream water supply passage section 8c connected to the bottom of the hot water storage tank 4. A pressure reducing valve 8d is installed in the upstream water supply passage section 8a, and a check valve 8e is installed in the intermediate water supply passage section 8b.

[0021] A bypass passage 17, which connects to the hot water supply system passage 9, branches off between the upstream water supply passage 8a and the intermediate water supply passage 8b. A check valve 17a is installed in the bypass passage 17. A bypass passage 18, which connects to the heat utilization circulation circuit 14, branches off between the intermediate water supply passage 8b and the downstream water supply passage 8c. A heat storage switching valve 19 is installed at this branch. This bypass passage 18 allows low-temperature clean water to be supplied to the heat utilization circulation circuit 14, and conversely, allows hot water to be returned from the heat utilization circulation circuit 14 to the hot water storage tank 4.

[0022] Next, the hot water supply passage 9 will be described. The hot water supply system passage 9 supplies hot water stored in the hot water storage tank 4 to the desired hot water supply destination such as a bath, and includes a hot water supply passage 21 connected to a hot water tap, a tank hot water outlet passage 22 connected from the top of the hot water storage tank 4 to the hot water supply passage 21, an auxiliary heating passage 23 branching off from the tank hot water outlet passage 22 and connected to a combustion-type auxiliary heat source unit 5, and an auxiliary heat source unit hot water outlet passage 24 connected from the auxiliary heat source unit 5 to the hot water supply passage 21.

[0023] The hot water supply passage 21 has an upstream hot water supply passage section 21a through which high-temperature hot water flows, an intermediate hot water supply passage section 21b through which mixed hot water flows, and a downstream hot water supply passage section 21c, and the upstream end of the upstream hot water supply passage section 21a is connected to the tank hot water outlet passage 22, and the downstream end of the downstream hot water supply passage section 21c is connected to the hot water tap.

[0024] A mixing valve 25 is installed between the upstream hot water supply passage 21a and the intermediate hot water supply passage 21b. A bypass passage 17 branching off from the water supply system passage 8 is connected to this mixing valve 25. The mixing valve 25 controls the mixing ratio of low-temperature clean water and high-temperature hot water so that the hot water outlet temperature becomes the command temperature. A flow rate sensor 21d and a hot water outlet proportioning valve 26 are installed in the intermediate hot water supply passage 21b. A branch passage 27 branching off from the bypass passage 17 is connected to the intermediate hot water supply passage 21b, and a high-temperature hot water outlet avoidance solenoid valve 28 is installed in the branch passage 27.

[0025] The tank hot water outlet passage 22 has an upper outflow hot water passage section 22a and a lower outflow hot water passage section 22b, with the upstream end of the upper outflow hot water passage section 22a connected to the top of the hot water storage tank 4 and the downstream end of the lower outflow hot water passage section 22b connected to the hot water supply passage 21. An auxiliary heating passage 23 branches off between the upper outflow hot water passage section 22a and the lower outflow hot water passage section 22b.

[0026] The auxiliary heating passage 23 has an upstream heating passage section 23a and a downstream heating passage section 23b, with the upstream end of the upstream heating passage section 23a connected to the tank hot water outlet passage 22 and the downstream end of the downstream heating passage section 23b connected to the inlet of the auxiliary heat source unit 5. A check valve 23c is installed in the upstream heating passage section 23a, and a pressure pump 29 and a flow rate sensor 23d are installed in the downstream heating passage section 23b.

[0027] A three-way valve 31 is provided between the upstream heating passage 23a and the downstream heating passage 23b, which can switch between the tank hot water outlet passage 22 and the auxiliary heating passage 23. The hot water return passage 14d of the heat utilization circulation circuit 14 is also connected to the three-way valve 31. This three-way valve 31 can switch between connection and disconnection between the upstream heating passage 23a and the downstream heating passage 23b, and between the downstream heating passage 23b and the hot water return passage 14d, and can connect all of the passages, the upstream heating passage 23a, the downstream heating passage 23b, and the hot water return passage 14d.

[0028] The auxiliary heat source unit hot water outlet passage 24 has an upstream auxiliary hot water outlet passage section 24a and a downstream auxiliary hot water outlet passage section 24b, with the upstream end of the upstream auxiliary hot water outlet passage section 24a connected to the outlet of the auxiliary heat source unit 5 and the downstream end of the downstream auxiliary hot water outlet passage section 24b connected to the upstream end of the hot water supply passage 21. Hot water supply side passage section 14a of the heat utilization circulation circuit 14 branches off between the upstream auxiliary hot water outlet passage section 24a and the downstream auxiliary hot water outlet passage section 24b. A tank water proportional valve 32 is installed in the downstream auxiliary hot water outlet passage section 24b.

[0029] Next, the control unit 10 will be described. The hot water storage and hot water supply device 2 is controlled by a control unit 10. Detection signals from various sensors are sent to the control unit 10, which controls the operation of the hot water storage and hot water supply device 2, the start / stop of various pumps, the switching of the open / closed state of various valves and adjustment of their opening degrees, etc., and performs various operations (hot water supply operation, hot water filling operation, reheating operation, high-temperature hot water supply operation, heating operation, anti-freeze operation during normal power generation operation, anti-freeze operation during stand-alone power generation operation, exhaust heat recovery operation, etc.).

[0030] The control unit 10 is capable of data communication with an operation remote controller 20 that can be operated by the user, and when various operations are set by operating the switches on the operation remote controller 20, a command signal is sent from the operation remote controller 20 to the control unit 10.

[0031] Next, the fuel cell power generation system 3 will be briefly described. As shown in FIG. 2, the fuel cell power generation system 3 has a power generation device cooled by cooling water taken out from the bottom of the hot water storage tank 4, and is an external heat source for the hot water storage and water heater 2 for heating hot water.

[0032] This fuel cell power generation system 3 is a typical system including a fuel cell power generation module 40, a fuel reforming air blower 41, a cathode air blower 42, a fuel gas pressure increasing means 43, an exhaust gas discharge passage 44, a heat exchanger 45 for exhaust heat recovery, a water treatment means 46, an inverter 47, a desulfurizer 48, and a heat dissipation means 49 having a blower fan 49a and a radiator 49b. These devices and piping are housed in an exterior case 3a. A circulation pump 50 is also provided to circulate the cooling water that flows from the circulation forward passage 15a to the circulation return passage 15b.

[0033] The fuel cell power generation module 40 comprises a fuel cell stack 40a, an evaporator 40b, a fuel reformer 40c, an off-gas combustion chamber 40d, etc., and generates electricity by chemically reacting the reformed fuel gas reformed by the fuel reformer 40c and air as an oxidant in the fuel cell stack 40a.

[0034] The DC power generated by the fuel cell power generation module 40 is converted to AC power via an inverter 47 and output to the outside. The exhaust gas discharged from the fuel cell power generation device 3 is subjected to heat exchange with the hot water circulating through the circulation forward passage 15a and the circulation return passage 15b in the exhaust heat recovery heat exchanger 45, where the temperature of the exhaust gas is reduced before being discharged to the outside.

[0035] The fuel cell stack 40a is made up of multiple fuel cell units. The evaporator 40b generates steam to be mixed with the fuel gas and supplies it to the fuel reformer 40c. The fuel reformer 40c has a reforming catalyst such as nickel or platinum, and mixes and reacts the desulfurized fuel gas with air and steam to generate reformed fuel gas.

[0036] Next, the desulfurizer 48 will be described. 2, the desulfurizer 48 is provided to remove (desulfurize) sulfur compounds contained in the fuel gas supplied to the fuel reformer 40c, and is provided in the fuel gas supply passage 51 of the fuel gas pressure increasing means 43. The desulfurizer 48 is filled with a desulfurizing material such as zeolite, silica gel, or activated carbon, but the material of the desulfurizing material is not particularly limited.

[0037] Fuel gas is taken in from the gas supply source through an electromagnetic valve 43a and a gas governor 43b into a fuel boost blower 43c, and the pressurized fuel gas flows into a desulfurizer 48 through a buffer tank 43d and a flow sensor 43e. The fuel gas desulfurized in the desulfurizer 48 is then supplied to a fuel reformer 40c via an evaporator 40b in the fuel cell power generation module 40.

[0038] Next, the hot water tank 4 and its peripheral equipment will be described. As shown in Figures 3 and 4, a bypass passage 15c is provided which connects a circulation forward passage 15a extending from the bottom of the hot water storage tank 4 to the fuel cell power generation system 3 with a circulation return passage 15b returning from the fuel cell power generation system 3 to the top of the hot water storage tank 4, and a three-way valve 33 is interposed at the connection between this bypass passage 15c and the circulation return passage 15b.When the temperature of the cooling water returning from the fuel cell power generation system 3 to the circulation return passage 15b is low, the hot water is circulated in the order of the circulation forward passage 15a, the fuel cell power generation system 3, the circulation return passage 15b, and the bypass passage 15c.

[0039] A drain pipe 54 is connected to the bottom of the hot water storage tank 4, and a drain plug 55 is provided at the tip of this drain pipe 54. Water can be drained from the hot water storage tank 4 via the drain pipe 54 and the drain plug 55.

[0040] In an emergency (water outage or power outage), the hot water in the hot water tank 4 can be extracted and used for domestic purposes while continuing to generate electricity in the fuel cell power generation system 3, so that the hot water in the hot water tank 4 can be extracted and used for domestic purposes.The following water extraction pipe 56, emergency water extraction valve 57, and air charge section 58 are provided in the hot water tank 4.

[0041] The upper end of water extraction pipe 56 is connected to the middle section of hot water storage tank 4 or a section in the vicinity thereof, and the upper section of water extraction pipe 56 is bent downward outside hot water storage tank 4 and extends downward a predetermined distance. A manually openable emergency water extraction valve 57 is provided at the lower end of water extraction pipe 56. In the case of Figure 3, the length ratio of H1 and H2 shown in the figure is, for example, 1.2:1.0, but this is not limited to this and the length ratio of H1 and H2 may be, for example, 1.0:1.0.

[0042] The air charge section 58 is composed of an air charge pipe 58a and an air charge valve 58b, and the upper end of the air charge pipe 58a is connected to the tank hot water outlet passage 22 near the top of the hot water storage tank 4, and the air charge pipe 58a extends sideways and then bends and extends downward for a predetermined length. A manually openable air charge valve 58b is installed at the lower end of the air charge pipe 58a.

[0043] Figure 3 shows normal usage conditions, not an emergency, in which a low-temperature layer 4u made of low-temperature water is formed in the lower and middle parts of the hot water storage tank 4, a medium-temperature layer 4v made of medium-temperature water is formed above the low-temperature layer 4u, and a high-temperature layer 4w made of high-temperature water is formed in the upper part of the hot water storage tank 4. However, the thicknesses of the low-temperature layer 4u, medium-temperature layer 4v, and high-temperature layer 4w are not constant, but vary depending on the hot water consumption situation and consumption rate.

[0044] Next, the operation and effects of the hot water storage system 1 will be described. In an emergency, when continuing to generate electricity using the fuel cell power generation system 3 while extracting hot water from the hot water storage tank 4 to use for daily use, etc., as shown in Figure 4, open the air charge valve 58b of the air charge section 58, place a container such as a bucket below the water extraction pipe 56, then open the emergency water extraction valve 57 to extract the hot water from the hot water storage tank 4 into the container.

[0045] Since the water extraction pipe 56 is connected to the middle section of the hot water storage tank 4 or its vicinity, as shown in Figure 4, hot water cannot be extracted from the lower half of the hot water storage tank 4, and hot water always remains in the lower half of the hot water storage tank 4, so power generation by the fuel cell power generation device 3 can continue as long as the hot water does not all become hot.

[0046] Next, modifications of the hot water tank 4 and its peripheral devices will be described. As shown in Figure 5, a connecting passage 59 is provided that connects the top of the hot water storage tank 4 with the middle part of the hot water storage tank 4 or its vicinity, and a heat exchanger 60 for reheating the bath and a pump 61 for circulating hot water are installed in the connecting passage 59.

[0047] The water outlet pipe 56 for extracting hot water from the hot water storage tank 4 is provided so as to branch off from the lower end of the connecting passage 59. In this way, because the water outlet pipe 56 branches off from the lower end of the connecting passage 59, there is no need to weld the water outlet pipe 56 to the hot water storage tank 4, which is advantageous in terms of manufacturing. The air charge pipe 58a is provided so as to branch off from the upper end of the connecting passage 59, and a manually openable air charge valve 58b is provided at the lower end of this air charge pipe 58a. In addition, the same functions and effects as those of the hot water storage system 1 described above are achieved.

[0048] In addition, those skilled in the art will appreciate that various modifications can be made to the above-described embodiments without departing from the spirit of the present invention. The present invention may be embodied in various forms and includes such modifications. [Explanation of symbols]

[0049] 1: Hot water storage system 2: Hot water storage unit 3: Fuel cell power generation equipment 4: Hot water tank 54: Drainage pipe 55: Drain plug 56: Water extraction pipe 57: Emergency water outlet valve 58:Air charge section 59: Connecting passage

Claims

1. A hot water storage system equipped with a hot water storage tank for storing hot water and a power generator cooled by water extracted from the bottom of the hot water storage tank. The hot water storage tank is provided with an emergency water outlet valve for taking out hot water from the hot water storage tank in an emergency, a water outlet pipe for taking out hot water from the middle part of the hot water storage tank in the height direction or a part nearby, an air charge part capable of introducing air into the hot water storage tank, and a connecting passage connecting the top of the hot water storage tank with the middle part of the hot water storage tank in the height direction or a part nearby, the water outlet pipe is provided so as to branch off from the lower end portion of the connecting passage, A hot water storage system characterized in that an emergency water outlet valve is connected to the water outlet pipe.

2. A hot water storage system as described in claim 1, characterized in that it has a drain pipe connected to the lower end of the hot water storage tank and a drain plug provided at the lower end of the drain pipe.

Images