Storage tank type hot water supply device

Abstract

To provide a storage type water heater which enables hot water in a hot water storage tank to be taken out by operation of a pump in a state that water flow of a water pipe is stopped while inhibiting occurrence of cavitation.SOLUTION: In a storage type water heater 10 which supplies hot water in a hot water storage tank 12 to a first cock 13 during normal time in which water of a water pipe 11 is supplied to the hot water storage tank 12, control means causes a pump 45 to operate to bring the storage type water heater 10 into an emergency water supply state in which hot water in the hot water storage tank 12 is discharged from a second cock 48 via a water line 49. In the emergency water supply state, the control means detects a temperature of hot water at a lower part of the hot water storage tank 12 being lower than a setting temperature T to bring a circulation circuit 44 into a water stop state in which returning of hot water into the hot water storage tank 12 is stopped. The control means detects the temperature of the hot water at the lower part of the hot water storage tank 12 being the setting temperature T or higher to bring the circulation circuit 44 into a circulation state in which hot water is returned to the hot water storage tank 12.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to a storage type hot water supply device that supplies hot water in a hot water storage tank to the outside. [Background technology]

[0002] A hot water storage type water heater uses the water pressure of the water pipes to supply hot water, which is obtained by mixing hot water from a hot water storage tank with water from a water pipe, or water from the water pipe (hereinafter, hot water or water will be referred to as "hot water") to a water faucet installed in a kitchen or bathroom (see Patent Documents 1 and 2). Therefore, under normal circumstances, hot water can be dispensed from the faucet by opening the faucet. However, if a natural disaster or other event causes the water supply infrastructure to fail, the flow of water in the water pipes to stop, and water pressure in the water pipes is lost, no hot water will come out of the tap even if the tap is opened.In contrast, a hot water storage type water heater that has a drain hose installed at the bottom of the hot water storage tank can discharge hot water from the hot water storage tank through the drain hose even when water pressure in the water pipes is lost. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2014-196887 A [Patent Document 2] JP 2017-129328 A Summary of the Invention [Problem to be solved by the invention]

[0004] Here, this type of hot water storage type hot water supply device is designed to use gravity to drain hot water from the drain hose, so the hot water outlet of the drain hose is located in the hot water storage tank. However, if the hot water in the hot water storage tank is made to drain from the drain hose by operating a pump, it becomes possible to set the drain hose outlet at a distance from the hot water storage tank.

[0005] However, in this case, the hot water in the hot water storage tank is drawn into the pump without being mixed with tap water, so the pump may draw in hot water at a high temperature (for example, 70°C). If the water pressure applied to the pump is low and the temperature of the hot water drawn into the pump is high, cavitation, which generates air bubbles, is likely to occur inside the pump. Cavitation can cause problems such as air entrapment and noise in the pump. The present invention has been made in consideration of the above-mentioned circumstances, and aims to provide a storage-type hot water supply device that can extract hot water from a hot water storage tank by operating a pump when the flow of water in the water pipes has stopped, while suppressing the occurrence of cavitation. [Means for solving the problem]

[0006] The hot water storage type hot water supply device of the present invention, which meets the above-mentioned objectives, is a hot water storage type hot water supply device that supplies hot water in the hot water storage tank to a first water faucet during normal times when water from a water pipe is supplied to the hot water storage tank, and is equipped with a pump, a circulation circuit that operates the pump to return hot water obtained from the lower part of the hot water storage tank to the upper or lower part of the hot water storage tank, a second water faucet to which hot water from the lower part of the hot water storage tank is sent via a water supply pipe whose upstream end is connected to the circulation circuit, and a control means that operates the pump to switch to an emergency water supply state in which the hot water in the hot water storage tank flows out of the second faucet via the water supply pipe, and in the emergency water supply state, the control means detects that the temperature of the hot water in the lower part of the hot water storage tank is below a set temperature T and switches the circulation circuit to a water stop state in which the hot water is not returned to the hot water storage tank, and detects that the temperature of the hot water in the lower part of the hot water storage tank is above the set temperature T and switches the circulation circuit to a circulation state in which the hot water is returned to the hot water storage tank. Effect of the Invention

[0007] In the storage type hot water supply device of the present invention, in an emergency water supply state, the control means detects that the temperature of the hot water at the bottom of the hot water storage tank is below the set temperature T, and switches the circulation circuit to a water-stopped state in which the hot water is not returned to the hot water storage tank, and detects that the temperature of the hot water at the bottom of the hot water storage tank is above the set temperature T, and switches the circulation circuit to a circulating state in which the hot water is returned to the hot water storage tank.Therefore, before a situation occurs in which cavitation is likely to occur within the pump, i.e., before the pump draws in high-temperature hot water, the amount of hot water drawn into the pump per unit time can be increased, and the occurrence of cavitation can be suppressed when the flow of water in the water pipe is stopped, making it possible to extract hot water from the hot water storage tank by operating the pump. [Brief description of the drawings]

[0008] [Figure 1] 1 is a circuit diagram of a storage type hot water supply device according to one embodiment of the present invention. [Diagram 2] FIG. 2 is a block diagram showing connections of a control means. [Diagram 3] FIG. 2 is an explanatory diagram showing the process of boiling water in a hot water storage tank. [Figure 4] FIG. 2 is an explanatory diagram showing the process of boiling water in a hot water storage tank. [Diagram 5] FIG. 13 is an explanatory diagram of an emergency water supply state when the boiling circuit is stopped. [Figure 6] FIG. 13 is an explanatory diagram of an emergency water supply state when the boiling circuit is in a circulating state. [Figure 7] FIG. 13 is an explanatory diagram showing the experimental results in a circulating state. [Figure 8] FIG. 13 is an explanatory diagram showing the experimental results in a water-stopped state. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Next, with reference to the attached drawings, an embodiment of the present invention will be described for understanding the present invention. As shown in Figure 1, a storage type hot water supply device 10 according to one embodiment of the present invention is a device that supplies hot water in a hot water storage tank 12 to a first faucet 13 during normal operation when water from a water pipe 11 is supplied to the hot water storage tank 12.

[0010] 1, a plurality of (six in this embodiment) temperature sensors 14, 14a, 14b, 14c, 14d, and 14e are attached to the hot water storage tank 12. Of the temperature sensors 14, 14a, 14b, 14c, 14d, and 14e, the temperature sensor 14 is disposed at the highest position, followed by the temperature sensors 14, 14a, 14b, 14c, 14d, and 14e in descending order. To the lower part of the hot water storage tank 12, one end of a water pipe 11 is connected, on which a pressure reducing valve 15, a temperature sensor 16, and check valves 17 and 18 are provided.

[0011] The upper end of a hot water supply pipe 20, whose downstream end is connected to a first water faucet 13, is connected to the top of the hot water storage tank 12. A check valve 21, a mixing valve 24, a water volume sensor 22, and a temperature sensor 23 are provided in the hot water supply pipe 20 from the upstream end to the downstream end, and another end of the water pipe 11 is connected to the mixing valve 24. As shown in Fig. 2, the mixing valve 24 is connected to a control means 25 constituted by an IC chip or the like, together with the temperature sensors 14, 14a, 14b, 14c, 14d, 14e, 16, 23, and the water volume sensor 22.

[0012] The control means 25 is connected to an operation terminal 26 through which various input operations, including an operation for inputting the temperature of hot and cold water to be supplied to the first water faucet 13, are performed. The control means 25 detects the measurement values ​​of the temperature sensors 14, 16, 23 and the water volume sensor 22, and based on these measurement values, adjusts the mixing ratio of the hot water supplied from the top of the hot water storage tank 12 and the water from the water pipe 11 through the mixing valve 24, thereby controlling the temperature of the hot water sent from the mixing valve 24 to the first faucet 13 to be the temperature set on the operation terminal 26.

[0013] In addition, as shown in Figure 1, the upstream end of a hot water filling pipe 27 that supplies hot water to bathtub B and the upstream end of a heat exchange circulation circuit 28 that heats the hot water in bathtub B are connected to the hot water supply pipe 20. A check valve 29, a mixing valve 30, a water volume sensor 31, a solenoid valve 32, a check valve 33 and a temperature sensor 34 are provided in this order on the filling pipe 27 from its upstream end to its downstream end connected to the bathtub B, and another end of the water pipe 11 is connected to the mixing valve 30. The mixing valve 30, the water volume sensor 31, the solenoid valve 32 and the temperature sensor 34 are connected to the control means 25 as shown in FIG.

[0014] When the operation to fill bathtub B is performed using the operation terminal 26, the control means 25 opens the solenoid valve 32 so that the hot water from the top of the hot water storage tank 12 and the water from the water pipe 11, which are mixed in the mixing valve 30, are sent to bathtub B, and based on the detection values ​​of the temperature sensors 14, 16, 34 and the water volume sensor 31, the control means 25 adjusts the mixing ratio of the hot water from the top of the hot water storage tank 12 and the water from the water pipe 11, and controls the temperature of the hot water sent to bathtub B to the temperature set on the operation terminal 26.

[0015] As shown in Fig. 1, the heat exchange circulation circuit 28 has a check valve 36 and a pump 37, and its downstream end is connected to the hot water storage tank 12. A water level sensor 38, a water flow switch 39, a temperature sensor 40, and a pump 41 are provided in bathtub B, and the upstream end of a bath circulation circuit 42 is connected to the bath B, whose downstream end is connected to the hot water filling pipe 27. A heat exchanger 43 is attached to the heat exchange circulation circuit 28 and the bath circulation circuit 42, and the pumps 37, 41, the water level sensor 38, the water flow switch 39, and the temperature sensor 40 are connected to the control means 25, as shown in Fig. 2.

[0016] When the reheating operation is performed on the operation terminal 26, the control means 25 operates the pumps 37, 41 to return the hot water in the upper part of the hot water storage tank 12 to the hot water storage tank 12 through part of the hot water supply pipe 20 and the heat exchange circulation circuit 28, and to return the hot water in the bathtub B to the bathtub B through the bath circulation circuit 42 and part of the water filling pipe 27. As a result, heat is exchanged between the hot water flowing through the heat exchange circulation circuit 28 and the hot water flowing through the bath circulation circuit 42 by the heat exchanger 43, the hot water flowing through the bath circulation circuit 42 is heated, and the temperature of the hot water in the bathtub B rises.

[0017] Normally, a certain water pressure is generated in water pipe 11, and when first water faucet 13 is opened (or bathtub B is filled with water), the water pressure in water pipe 11 causes hot water to come out of first water faucet 13 (hot water flows into bathtub B), and the same amount of water as that sent out from the top of hot water storage tank 12 flows from water pipe 11 into the bottom of hot water storage tank 12. Therefore, under normal circumstances, hot water storage tank 12 is filled with hot water. In contrast, in an emergency when the required water pressure is not generated in the water pipe 11, even if the first water faucet 13 or the solenoid valve 32 is opened, the hot water in the hot water storage tank 12 will not flow out from the top of the hot water storage tank 12 to the hot water supply pipe 20, and the hot water will not be sent to the first water faucet 13 or the bathtub B.

[0018] Additionally, the upstream end of a boiling circuit (one example of a circulation circuit) 44 is connected to the lower part of the hot water storage tank 12, the downstream end of which is connected to the upper and lower parts of the hot water storage tank 12. As shown in Figures 1 and 2, the boiling circuit 44 has a pump 45, a heating means 46, and a switching means 47, each connected to the control means 25, and when the pump 45 is operated by the control means 25, the hot water obtained from the lower part of the hot water storage tank 12 is circulated and returned to the upper or lower part of the hot water storage tank 12 (hereinafter, this state will be referred to as a circulation state) as shown in Figures 3 and 4.

[0019] The pump 45, the heating means 46, and the switching means 47 are arranged in order along the flow of hot water through the boiling circuit 44. The boiling circuit 44 branches into two downstream of the switching means 47, one of which is connected to the top of the hot water storage tank 12, and the other is connected to the bottom of the hot water storage tank 12. The heating means 46 is operated by the control means 25 to heat the hot water circulating through the boiling circuit 44.

[0020] The switching means 47 can switch the destination of the hot water that has passed through the heating means 46 from one of the upper and lower parts of the hot water storage tank 12 to the other. When the control means 25 detects that the amount of hot water (amount of boiling water) in the hot water storage tank 12 has decreased based on the measured temperatures of each of the temperature sensors 14, 14a, 14b, 14c, 14d, and 14e, it operates the pump 45 and the heating means 46 to circulate the hot water in the lower part of the hot water storage tank 12 to the boiling circuit 44, and boils the hot water storage tank 12.

[0021] When the temperature measured by a temperature sensor (not shown) provided in heating means 46 that measures the temperature of hot water passing through heating means 46 is below a predetermined value, control means 25 causes switching means 47 to send the hot water to the lower part of hot water storage tank 12, as shown in Fig. 3. This causes boiling circuit 44 to enter a circulation state in which it obtains water from the lower part of hot water storage tank 12 and returns it to the lower part of hot water storage tank 12, preventing low-temperature hot water from flowing into the upper part of hot water storage tank 12.

[0022] Then, when the control means 25 detects that the temperature of the hot water passing through the heating means 46 has reached or exceeded a predetermined value, it switches the destination of the hot water by the switching means 47 to the upper part of the hot water storage tank 12, as shown in Fig. 4. This causes the boiling circuit 44 to enter a circulation state in which it obtains water from the lower part of the hot water storage tank 12 and returns it to the upper part of the hot water storage tank 12, so that the hot water heated by the heating means 46 is supplied to the upper part of the hot water storage tank 12.

[0023] After the hot water storage tank 12 has been completely heated, the switching means 47 changes the destination to the upper part of the hot water storage tank 12, and when the hot water storage tank 12 is heated again, if the temperature of the hot water passing through the heating means 46 is below a predetermined value, the control means 25 switches the destination to the lower part of the hot water storage tank 12.

[0024] In this embodiment, a heat pump unit is used for the heating means 46, and a three-way valve is used for the switching means 47, but the present invention is not limited to these. For example, a heating means that uses exhaust heat generated during power generation by the private generator to heat the hot water flowing through the boiling circuit, or a switching means configured with two solenoid valves can be used. When a heating means that uses exhaust heat during power generation is used, the boiling circuit does not have a switching means, and the destination of the hot water heated by the heating means can be limited to the upper part of the hot water storage tank.

[0025] Additionally, the upstream end of a water supply pipe 49, whose downstream end is connected to a second water faucet 48, is connected to the area between the pump 45 and the heating means 46 of the boiling circuit 44. When a predetermined input operation is performed on the operation terminal 26, the control means 25 operates the pump 45, and places the hot water storage type hot water supply device 10 in a state in which hot water in the hot water storage tank 12 flows out of the second water faucet 48 via the water supply pipe 49, as shown in Figure 5 (hereinafter, this state will be referred to as the "emergency water supply state").

[0026] Therefore, in an emergency water supply state, hot water from the lower part of the hot water storage tank 12 is sent to the second faucet 48 via the water supply pipe 49, and the user can dispense hot water from the hot water storage tank 12 through the second faucet 48 by opening the second faucet 48. In the present embodiment, when the hot water in the hot water storage tank 12 is discharged from the second faucet 48 using the pump 45, the distance from the hot water storage tank 12 to the second faucet 48 can be made longer, and there is greater freedom in the placement of the second faucet 48, compared to when the hot water in the hot water storage tank 12 is discharged from the second faucet 48 using gravity alone.

[0027] As the hot water in the hot water storage tank 12 flows out from the second faucet 48, air taken in through the negative pressure operated valve 50 flows into the hot water storage tank 12, and air accumulates from the upper part inside the hot water storage tank 12. Furthermore, under normal circumstances, the second faucet 48 is closed so that hot water does not come out from the second faucet 48 even if the pump 45 is operated.

[0028] In this embodiment, the control means 25 can set the switching means 47 to a state in which the hot water in the boiling circuit 44 is not sent to either the upper or lower part of the hot water storage tank 12, and this sets the boiling circuit 44 in a state in which the return of hot water to the hot water storage tank 12 is stopped (hereinafter, this state is referred to as a water stop state). Therefore, the switching means 47 switches the flow path to set the boiling circuit 44 in a circulation state or a water stop state.

[0029] Depending on the structure of the switching means 47, even if the switching means 47 is set to a state in which hot water is not sent to either the upper or lower part of the hot water storage tank 12, a small amount of hot water may be sent to at least one of the upper and lower parts of the hot water storage tank 12 (for example, one-tenth the amount sent when the switching means 47 is set to a state in which hot water is sent to either the upper or lower part of the hot water storage tank 12). Therefore, setting the boiling circuit 44 to a water-stopping state means setting the switching means 47 to a state in which hot water is not actively (intentionally) sent to either the upper or lower part of the hot water storage tank 12.

[0030] Because the hot water in the upper part of hot water storage tank 12 is hotter than the hot water in the lower part of hot water storage tank 12, by continuously discharging hot water from second faucet 48, the temperature of the hot water that comes out of the lower part of hot water storage tank 12, enters boiling circuit 44, and is drawn into pump 45 increases over time. When the temperature of the hot water drawn into pump 45 increases, cavitation occurs in pump 45, causing problems such as air being trapped in pump 45, making pump 45 noisy, and in some cases causing pump 45 to malfunction.

[0031] Therefore, in an emergency water supply state, the boiling circuit 44 is switched from one of the circulation state and the water stop state to the other depending on the temperature of the hot water at the bottom of the hot water storage tank 12, thereby suppressing the occurrence of cavitation within the pump 45 and discharging the hot water from the hot water storage tank 12 from the second faucet 48. Specifically, the control means 25 detects the measurement value of the temperature sensor 14e continuously or intermittently, and when it detects that the measurement value of the temperature sensor 14e is less than a predetermined set temperature T, it switches the boiling circuit 44 to a water-stopped state as shown in Figure 5 (the boiling circuit 44 in the water-stopped state maintains the water-stopped state, and the boiling circuit 44 in the circulation state that sends hot water to the lower part of the hot water storage tank 12 is switched to a water-stopped state), and when it detects that the measurement value of the temperature sensor 14e is greater than or equal to the set temperature T, it switches the boiling circuit 44 to a circulation state that returns hot water to the lower part of the hot water storage tank 12 as shown in Figure 6 (the boiling circuit 44 in the circulation state that sends hot water to the lower part of the hot water storage tank 12 maintains the circulation state, and the boiling circuit 44 in the water-stopped state is switched to a circulation state that sends hot water to the lower part of the hot water storage tank 12).

[0032] The set temperature T is set to a temperature that is 5° C. to 15° C. lower than the temperature at which cavitation is thought to occur significantly in pump 45. In this embodiment, a temperature of 60° C. or higher and 70° C. or lower is used as T. The reason for carrying out such control is that the following 1) to 3) have been confirmed through various experimental verifications, etc.

[0033] 1) When hot water from the bottom of the hot water storage tank 12 is discharged from the second faucet 48, the amount of hot water sucked into the pump 45 per unit time is greater when the boiling circuit 44 is in a circulating state than when the boiling circuit 44 is in a stopped state. 2) By increasing the amount of hot water and cold water sucked into the pump 45 per unit time, the occurrence of cavitation can be suppressed. 3) Under conditions where no cavitation is occurring within pump 45, the amount of hot or cold water coming out of second faucet 48 per unit time is less when boiling circuit 44 is in a circulating state than when boiling circuit 44 is in a stopped state.

[0034] Furthermore, when the measurement value of temperature sensor 14e is less than set temperature T, control means 25 sets boiling circuit 44 to a circulation state that sends hot water to the lower part of hot water storage tank 12 instead of to the upper part of hot water storage tank 12, in order to avoid low-temperature hot water flowing into the upper layer of hot water in hot water storage tank 12 and to prevent noise from being generated in hot water storage tank 12. Note that in the emergency water supply state, heating means 46 is stopped, so the hot water that passes through heating means 46 and is sent to hot water storage tank 12 is not heated by heating means 46.

[0035] When hot water is dispensed from second faucet 48, air accumulates at the top of hot water storage tank 12. If hot water is sent to the top of hot water storage tank 12 where air has accumulated, noise will be generated as the hot water falls from the top of hot water storage tank 12 to the surface of the hot water in hot water storage tank 12. To prevent this noise from occurring, it is effective to send hot water to the bottom of hot water storage tank 12. From the perspective of preventing cavitation from occurring in pump 45, control means 25 may detect that the temperature of the hot water at the bottom of hot water storage tank 12 is equal to or higher than set temperature T, and set boiling circuit 44 to a circulation state in which hot water is returned to the top of hot water storage tank 12.

[0036] Since there is a possibility that hot water may come out from second faucet 48, in this embodiment, a notice is provided near second faucet 48 that warns about the possibility of hot water coming out, in addition to instructions on how to use second faucet 48. Also, in this embodiment, pump 45 is installed upstream of the point where water supply pipe 49 of boiling circuit 44 is connected, so that pump 45 can be used both to boil hot water storage tank 12 and to supply hot water from second faucet 48 in hot water storage tank 12.

[0037] Furthermore, the control means 25 can, by a predetermined input operation on the operation terminal 26, put the hot water storage type hot water supply apparatus 10 into an emergency restriction state which prohibits the operation of the heating means 46, the filling of bathtub B with hot water, and the reheating of hot water in bathtub B. In this embodiment, on the operation terminal 26, an input operation for putting the hot water storage type hot water supply apparatus 10 into the emergency restriction state and an input operation for putting the hot water storage type hot water supply apparatus 10 into the emergency water supply state are performed by a common button. When the same button is continuously pressed (long pressed) for a certain period of time (e.g., 5 seconds), the control means 25 puts the hot water storage type hot water supply apparatus 10 into the emergency restriction state, and when the same button is pressed and held again, the emergency restriction state of the hot water storage type hot water supply apparatus 10 is released. When the hot water storage type hot water supply device 10 is in the emergency restriction state, the control means 25 switches the device to the emergency water supply state while maintaining the emergency restriction state by pressing the button normally rather than pressing and holding the button, and when the button is pressed normally again, only the emergency water supply state is released. EXAMPLES

[0038] Next, an experiment conducted to confirm the effects of the present invention will be described. The pump was operated, the second faucet was opened, and hot water at about 75°C in the hot water storage tank was discharged from the second faucet. The pump rotation speed was measured when the boiling circuit was in a circulating state returning hot water to the bottom of the hot water storage tank, and when the boiling circuit was in a stopped state. The measurement results for the circulating state and the stopped state are shown in Figures 7 and 8, respectively.

[0039] The experimental results confirmed that in the circulation state, the pump speed was stable without any fluctuations, and therefore no cavitation occurred within the pump. On the other hand, in the stopped water state, the pump speed fluctuated wildly about 18 minutes after the start of the measurement. This fluctuation in the pump speed is thought to be caused by cavitation occurring within the pump.

[0040] Although the embodiment of the present invention has been described above, the present invention is not limited to the above-mentioned embodiment, and all changes in conditions that do not depart from the gist of the present invention are within the scope of application of the present invention. For example, the circulation circuit may be a circuit having a pump to circulate hot water in the hot water storage tank, and it goes without saying that the circulation circuit does not need to be a boiling circuit or have a heating means. Also, a circulation circuit without a switching means may be adopted. [Explanation of symbols]

[0041] 10: storage type hot water supply device, 11: water pipe, 12: hot water tank, 13: first water faucet, 14, 14a, 14b, 14c, 14d, 14e: temperature sensor, 15: pressure reducing valve, 16: temperature sensor, 17, 18: check valve, 20: hot water supply pipe, 21: check valve, 22: water volume sensor, 23: temperature sensor, 24: mixing valve, 25: control means, 26: operation terminal, 27: hot water filling pipe, 28: heat exchange circulation circuit, 29: reverse Stop valve, 30: mixing valve, 31: water volume sensor, 32: solenoid valve, 33: check valve, 34: temperature sensor, 36: check valve, 37: pump, 38: water level sensor, 39: water flow switch, 40: temperature sensor, 41: pump, 42: bath circulation circuit, 43: heat exchanger, 44: boiling circuit, 45: pump, 46: heating means, 47: switching means, 48: second faucet, 49: water supply pipe, 50: negative pressure actuated valve, B: bathtub

Claims

1. In a storage-type hot water supply device, when water from a water pipe is normally supplied to the hot water storage tank, hot water in the hot water storage tank is supplied to a first water faucet, A circulation circuit having a pump, the pump being operated to return hot water taken from a lower part of the hot water storage tank to an upper part or a lower part of the hot water storage tank; A second faucet through which hot water from the lower part of the hot water storage tank is sent via a water supply pipe whose upstream end is connected to the circulation circuit; a control means for operating the pump to bring the hot water in the hot water storage tank into an emergency water supply state in which the hot water flows through the water supply pipe and out of the second water faucet; A hot water storage type hot water supply device characterized in that, in the emergency water supply state, the control means detects that the temperature of the hot water at the bottom of the hot water storage tank is below a set temperature T, and sets the circulation circuit to a water-stopped state in which the hot water is not returned to the hot water storage tank, and detects that the temperature of the hot water at the bottom of the hot water storage tank is above the set temperature T, and sets the circulation circuit to a circulating state in which the hot water is returned to the hot water storage tank.

2. 2. The storage type hot water supply apparatus according to claim 1, wherein the circulation circuit further comprises a heating means for heating the hot water circulating through the circulation circuit.

3. In the storage type hot water supply device described in claim 1 or 2, the circulation circuit further has a switching means for switching the flow path to place the circulation circuit in the circulation state or the water stop state, and the control means detects that the temperature of the hot water at the bottom of the hot water storage tank is above the set temperature T, and places the circulation circuit in the circulation state in which the hot water is returned to the bottom of the hot water storage tank.

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