JP6385184B2 - Hot water storage system - Google Patents

Description

  The present invention relates to a hot water storage system in which water stored in a hot water storage tank is heated by hot water exhausted to supply hot water.

  When cooling a fuel cell with exhaust heat recovery by a hot water storage system, if the hot water tank is filled with hot water (hereinafter referred to as full storage), cooling by exhaust heat recovery will no longer be possible. Battery power generation cannot be continued.

  Therefore, when the hot water storage tank is full, if there is a reserved bath, there is a system that operates the fuel cell by putting hot water into the bath before the reservation time is reached to eliminate the full storage (Patent Document) 1).

  By the way, when an earthquake occurs, pollutants may flow into rivers from damaged factories. When the water purification plant detects that the river is contaminated, the water purification plant stops water intake from the river to prevent contamination of the water purification plant. For this reason, when a certain amount of time has passed since the occurrence of the earthquake, the water may stop.

  Therefore, there is a hot water supply system that automatically stores water in a bathtub and secures water for daily use in the event of an earthquake in preparation for a water outage after the occurrence of an earthquake (see Patent Document 2).

Japanese Patent No. 4295699 JP 2006-22970 A

  Normally, in a hot water storage system, a water supply is connected to the water intake of the hot water storage tank, and when the faucet is opened, the hot water in the hot water storage tank flows out to the faucet with the water pressure supplied from the water intake. . For this reason, if the water supply is stopped and water is not replenished, even if hot water is in the hot water storage tank, the hot water cannot be taken out from the faucet.

  In addition, a power failure is likely to occur after an earthquake, so it is desirable to continue power generation of the fuel cell until the power failure is restored. However, when the water is cut off, the hot water is not replenished to the hot water storage tank, and if the exhaust heat recovery of the fuel cell by the hot water storage system is continued, the hot water storage tank will eventually become full. If this happens, the fuel cell cannot be cooled any more by the exhaust heat recovery of the hot water storage system, and the fuel cell cannot continue power generation.

  An object of the present invention is to provide a hot water storage system capable of continuing the power generation of a fuel cell for a long time even when water is cut off after an earthquake occurs.

  The gist of the present invention for achieving the object lies in the inventions of the following items.

[1] A hot water storage system that includes a hot water storage tank that stores hot water supplied for hot water supply and that is replenished with clean water so that the water becomes full, and recovers exhaust heat of the fuel cell to raise the temperature of the water in the hot water storage tank. There,
A drainage section for draining hot water in the hot water storage tank;
Regardless of whether or not the hot water storage tank is full when an earthquake is detected , the drainage unit is operated, the hot water in the hot water storage tank is drained and replaced with clean water, and
A hot water storage system characterized by comprising:

  In the above invention, when an earthquake is detected, the hot water in the hot water storage tank is drained and replaced with clean water. As a result, even if the water is shut off after the occurrence of the earthquake, the fuel cell can be cooled with the water in the hot water storage tank for a long time, and the operation of the fuel cell can be ensured.

[2] The hot water storage system according to [1], wherein the drainage section drains hot water in the hot water storage tank into a bathtub.

  In the above-described invention, the hot water in the hot water storage tank is discharged into the bathtub, so that the hot water can be effectively used and bathing in a warm bath becomes possible.

[3] The hot water storage tank is provided with a replenishing port for clean water at the bottom,
The hot water storage system according to [1] or [2], wherein the drainage part drains hot water in the hot water storage tank from an upper part of the hot water storage tank.

  In the above-described invention, hot water stored in the upper part of the hot water storage tank can be drained, and hot water in the hot water storage tank can be efficiently replaced with clean water.

  According to the hot water storage system according to the present invention, power generation of the fuel cell can be continued for a long time even when water is shut off after the occurrence of an earthquake.

It is a figure which shows schematic structure of the bath hot-water supply system to which the hot water storage system of this invention is applied. It is a figure which shows the structural example of a bath water heater. It is explanatory drawing which shows the flow of the hot water in waste heat recovery operation | movement. It is explanatory drawing which shows the flow of the hot water in the hot water supply operation | movement of a 1st mode. It is explanatory drawing which shows the flow of the hot water in the hot water supply operation | movement of a 2nd mode. It is explanatory drawing which shows the flow of the hot water in the hot water supply operation | movement of a 3rd mode. It is explanatory drawing which shows the flow of the hot water in the draining to the bathtub after pouring operation and an earthquake occurrence. It is a flowchart which shows the operation | movement corresponding to the occurrence of an earthquake. It is explanatory drawing which shows the flow of the hot water in the case of draining outside. .

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

  FIG. 1 shows a configuration of a bath hot water supply system 10 to which a hot water storage system of the present invention is applied. The bath hot water supply system 10 includes a hot water storage tank unit 11, a fuel cell 4, an exhaust heat recovery device 50, and a bath water heater 70 as a backup heat source device. The piping between the apparatuses and the external piping are indicated by double arrows.

  The hot water storage tank unit 11 includes a hot water storage tank 13 that stores water supplied from a water supply pipe 12. The hot water storage tank 13 is a hollow, substantially cylindrical tank, with a water supply port 14 provided at the lower part and a hot water outlet 15 provided at the upper part. Further, a water intake port 16 is provided at the lower part of the hot water storage tank 13 and a return port 17 is provided at the upper part.

  The hot water storage tank 13 has, for example, a capacity of about 100 liters, and a first temperature sensor 18a for detecting the water temperature at the water level of 20 liters from the bottom has a water level of 40 liters from the bottom. A second temperature sensor 18b for detecting the water temperature at the location is located at a location where the water level is 60 liters from the bottom, and a third temperature sensor 18c for detecting the water temperature at the location is located at a location where the water level is 80 liters from the bottom. A hot water temperature sensor 18d for detecting the water temperature is further provided, and a tank upper temperature sensor 18e for detecting the water temperature at the location is provided at the uppermost part of the hot water storage tank 13, respectively.

  The exhaust heat recovery device 50 is provided inside the fuel cell 4 and recovers the exhaust heat of the fuel cell 4. The exhaust heat recovery device 50 includes an exhaust heat recovery heat exchanger 51 and an exhaust heat recovery pump 52. The exhaust heat recovery heat exchanger 51 of the hot water storage tank 13 and the exhaust heat recovery device 50 has a heat recovery pipe 53 (53a, 53b) so that an exhaust heat recovery circulation path for circulating the water of the hot water storage tank 13 is formed between them. ). Specifically, one end of a heat recovery pipe (low temperature) 53 a is connected to the water intake 16 of the hot water storage tank 13, and the other end of the heat recovery pipe (low temperature) 53 a is connected to the inlet side of the exhaust heat recovery heat exchanger 51. ing. The exhaust heat recovery pump 52 is inserted into a heat recovery pipe (low temperature) 53a in the vicinity of the entrance side of the exhaust heat recovery heat exchanger 51, and the exhaust heat recovery pump 52 uses the water in the heat recovery pipe (low temperature) 53a. Water is fed from the intake 16 side of the hot water storage tank 13 toward the entrance side of the exhaust heat recovery heat exchanger 51.

  A heat recovery pipe (high temperature) 53 b is connected to the outlet side of the exhaust heat recovery heat exchanger 51, and the other end of the heat recovery pipe (high temperature) 53 b is the first connection of the first three-way valve 21 in the hot water storage tank unit 11. It is connected to the mouth 21a.

  The first three-way valve 21 includes the first connection port 21a, the second connection port 21b, and the third connection port 21c, and connects the first connection port 21a and the second connection port 21b to form a third connection port. The connection state can be switched between the A direction for closing 21c and the B direction for connecting the first connection port 21a and the third connection port 21c and closing the second connection port 21b. The first three-way valve 21 is controlled by the control unit 20 so as to be in the A direction if the temperature of the water flowing in from the first connection port 21a is equal to or higher than the predetermined temperature, and to be switched to the B direction if the temperature is lower than the predetermined temperature.

  The second connection port 21 b of the first three-way valve 21 is connected to the return port 17 of the hot water storage tank 13. One end of the bypass pipe 54 is connected to the third connection port 21 c of the first three-way valve 21, and the other end of the bypass pipe 54 joins the heat recovery pipe (low temperature) 53 a in the hot water storage tank unit 11.

  A heat recovery pipe high temperature side temperature sensor 22a is provided in the heat recovery pipe (high temperature) 53b in the vicinity of the first connection port 21a of the first three-way valve 21, and a junction between the water intake 16 of the hot water storage tank 13 and the bypass pipe 54 is provided. The heat recovery pipe low temperature side sensor 22b is provided in the heat recovery pipe (low temperature) 53a until the above.

  The hot water storage tank unit 11 includes a mixer 23 that mixes hot water from the hot water outlet 15 of the hot water storage tank 13, hot water from the bath water heater 70, and water supply. This mixer 23 is actually a first mixer 23 a that adjusts the amount of hot water supplied from the hot water outlet 15 of the hot water storage tank 13 and a second mixer that adjusts the amount of hot water supplied from the bath water heater 70. 23 b and a third mixer 23 c that adjusts the amount of water supplied from the water supply pipe 12.

  The inlet side of the first mixer 23a is connected to a hot water outlet 15 of the hot water storage tank 13 by piping, and an overpressure relief valve 24, an intake valve 25, and a tank outlet temperature sensor 26 are provided in the middle of the piping. . The entrance side of the second mixer 23 b is connected to the hot water supply connection port of the bath water heater 70 by a connection pipe (high temperature) 61. A connecting pipe high temperature side temperature sensor 28 for detecting the water temperature in the connecting pipe (high temperature) 61 is provided at a predetermined location in the hot water storage tank unit 11 in the connecting pipe (high temperature) 61. A water supply pipe 12 is connected to the entrance side of the third mixer 23c.

  The outlet side of the first mixer 23a and the outlet side of the second mixer 23b merge, and after passing through the pipe provided with the hot water supply high temperature sensor 29, merge with the pipe from the outlet side of the third mixer 23c. It leads to the outlet of the mixer 23. A hot water supply pipe 31 is connected to the outlet of the mixer 23. A hot water supply temperature sensor 32 and a high cut temperature sensor 33 are provided in the hot water supply pipe 31 near the outlet of the mixer 23.

  The water supply pipe 12 inside the hot water storage tank unit 11 is provided with a flow rate sensor 34, a water supply temperature sensor 35, and a pressure reducing valve 36. The water supply pipe 12 branches into three downstream of these, one of which is connected to the inlet side of the third mixer 23c via a check valve 37a, and the other one via the check valve 37b. The other one is connected to the second connection port 38b of the second three-way valve 38 through the check valve 37c.

  The second three-way valve 38 includes a first connection port 38a, a second connection port 38b, and a third connection port 38c, connects the first connection port 38a and the second connection port 38b, and closes the third connection port 38c. The connection state can be switched between the C direction and the D direction in which the first connection port 38a and the third connection port 38c are connected and the second connection port 38b is closed. A pipe 31b branched from the hot water supply pipe 31 on the downstream side of the high cut temperature sensor 33 is connected to the third connection port 38c. A third three-way valve 43 and a check valve 39 are provided in the middle of the pipe 31b. The first connection port 38 a of the second three-way valve 38 is connected to the water supply connection port of the bath water heater 70 through a connection pipe (low temperature) 62.

  Further, a drain pipe 41 leading to a predetermined drainage point is connected to the water intake 16 of the hot water storage tank unit 11, and a drain plug 42 for opening and closing the pipe line is provided in the middle of the drain pipe 41.

  A pipe 31b from the hot water supply pipe 31 side is connected to the first connection port 43a of the third three-way valve 43, and a pipe 31b toward the third connection port 38c of the second three-way valve 38 is connected to the second connection port 43b. It is connected. The first connection port 43 a of the third three-way valve 43 is connected to the drain pipe 41 downstream of the drain plug 42. The third three-way valve 43 connects the first connection port 43a and the second connection port 43b, and connects the first connection port 43a and the third connection port 43c with the E direction in which the third connection port 43c is closed. The connection state can be switched to the F direction in which the second connection port 43b is closed. In the normal use state, the third three-way valve 43 is set in the E direction.

  The hot water storage tank unit 11 includes a control unit 20 that performs overall control of the operation of the hot water storage tank unit 11. The control unit 20 includes a CPU (Central Processing Unit), a flash ROM (Read Only Memory) that stores programs executed by the CPU, fixed data, and the like, and a RAM that temporarily stores various types of information when the CPU executes programs. (Random Access Memory) and an I / F (Interface) unit for inputting / outputting various signals and the like. Detection signals from various sensors of the hot water tank unit 11 are input to the control unit 20. A control signal is output from the control unit 20 to each valve and other controlled objects. The control unit 20 further exchanges various information and commands with the fuel cell 4 and the bath water heater 70.

  Next, a configuration example of the bath water heater 70 as a backup heat source device will be described. The bath water heater 70 has a function of heating and flowing out water flowing from a water supply connection port connected to a connection pipe (low temperature) 62, a function of pouring (hot water filling) the bath (tub) 2, and hot water in the bathtub. This is a gas-fired bath water heater having a function of reheating and a function of heating a heat radiator by flowing a heated heat medium fluid. In FIG. 2, the portion related to the heating function is omitted.

  The bath water heater 70 includes a can-two-water channel heat exchanger 72 through which the first heat exchange water pipe 72 a and the second heat exchange water pipe 72 b pass, and a burner 73 that heats the heat exchanger 72. A gas supply pipe 73a is connected to the burner 73, and a gas valve for switching supply / cutoff of gas and a proportional valve for adjusting the amount of supply gas are provided in the middle of the gas supply pipe 73a.

  The inlet side of the first heat exchange water pipe 72 a is connected to a water supply connection port by a water inlet pipe 74, and the outlet side of the first heat exchange water pipe 72 a is connected to a hot water supply connection port by a hot water outlet pipe 75. Further, a bath return pipe 76 leading to the bath (tub) 2 is provided on the entry side of the second heat exchange water pipe 72b, and a bath return pipe 77 similarly leading to the bath (tub) 2 is provided on the exit side of the second heat exchange water pipe 72b. Each is connected.

  The hot water outlet pipe 75 and the bath return pipe 76 are connected by a connecting pipe 78, and a hot water electromagnetic valve 79 for switching between closing and opening of the connecting pipe 78 is provided in the middle of the connecting pipe 78. In addition, a water amount servo 81 capable of adjusting the opening degree from a substantially closed state to a fully open state is provided in the middle of the hot water discharge pipe 75 upstream from the connection point of the connecting pipe 78 to adjust the amount of hot water discharged. A tapping temperature sensor 82 for detecting tapping temperature is provided on the downstream side of the water amount servo 81.

  Furthermore, a bypass pipe 83 branched from the water intake pipe 74 and joined to and connected to the hot water discharge pipe 75 at a predetermined location on the first heat exchange water pipe 72a side from the water quantity servo 81 is provided. A bypass adjustment valve 84 whose opening degree can be adjusted until it is fully opened is provided. The bypass adjustment valve 84 is adjusted so that hot water from the first heat exchange water pipe 72a and water via the bypass pipe 83 are mixed to become hot water at a set temperature. The inlet pipe 74 upstream of the branching point of the bypass pipe 83 is provided with a flow rate sensor 85 that detects the flow rate in the inlet pipe 74 and an incoming water temperature sensor 86 that detects the incoming water temperature.

  In the middle of the bath return pipe 76, a bath circulation pump 87 for circulating the water in the bath (tub) 2 through the recirculation circulation path (bath return pipe 76, second heat exchange water pipe 72 b, bath going-out pipe 77). Is provided. A flowing water switch 88 provided in the bath return pipe 76 detects whether water is actually circulating in the recirculation circulation path when the bath circulation pump 87 is operated.

  In addition, the bath return pipe 76 and the bath return pipe 77 are provided with a bath return temperature sensor 89a and a bath return temperature sensor 89b, respectively, for detecting the temperature in the pipe.

  The control unit 91 includes a CPU, a flash ROM that stores a program executed by the CPU, fixed data, and the like, and a RAM that temporarily stores various types of information when the CPU executes the program. Has been. Various sensors, valves, a bath circulation pump 87, and the like that the bath water heater 70 has are connected to the control unit 91.

  Normally, the remote controller 92 is directly connected to the control unit 91 via wiring. Here, however, the control unit 91 is operated in order to operate the bath water heater 70 under the control of the control unit 20 on the hot water tank unit 11 side. The remote controller (a remote controller common to the hot water storage tank unit 11 side and the bath water heater 70) 92 is connected to the controller 20 via the wiring. The remote control 92 is a switch for receiving various operations from the user, such as designation of hot water supply set temperature and bath set temperature, start / end instruction of hot water filling and reheating operation, power on / off, operation state and set temperature, etc. It is comprised with the display part etc. which display.

  In the hot water supply operation in which the controller 91 of the bath water heater 70 discharges hot water from the hot water supply connection port to the connection pipe (high temperature) 61, hot water at a temperature instructed by the control unit 20 on the hot water storage tank unit 11 side is connected to the connection pipe (high temperature) 61. The amount of combustion of the burner 73, the opening degree of the bypass adjustment valve 84, and the like are controlled so that the hot water is discharged.

  In the operation of pouring (hot water) into the bath (tub) 2, the opening of the water quantity servo 81 is adjusted while the burner 73 is burned by opening the pouring solenoid valve 79, thereby flowing from the water supply connection port. The hot water is heated through the first heat exchange water pipe 72a of the heat exchanger 72, and further from the hot water pipe 75 to the bath (tub) 2 through both (or one) of the connecting pipe 78, the bath return pipe 76 and the bath outlet pipe 77. Flow in (this path is a pouring circuit). At this time, the combustion amount of the burner 73, the opening degree of the bypass adjustment valve 84, and the like are controlled so that hot water having a bath setting temperature set by the user is poured by the remote controller 92. If the hot water supplied from the hot water storage tank unit 11 through the connection pipe (low temperature) 62 has already reached the bath set temperature and no additional heating is required in the bath water heater 70, the burner 73 is not burned. Perform hot water operation. The bath water heater 70 checks the water level in the bath (tub) 2, and the hot water pouring operation ends when the set water level is reached.

  In the reheating operation, the hot water solenoid valve 79 is closed, and the burner 73 is burned with the bath circulation pump 87 activated. As a result, hot water in the bath (tub) 2 is taken into the bath water heater 70 through the bath return pipe 76 and heated while passing through the second heat exchange water pipe 72 b of the heat exchanger 72, and the heated hot water is heated to the bath outlet pipe 77. It is returned to the bath (tub) 2 through.

  Next, various operations of the bath hot water supply system 10 will be described.

<Exhaust heat recovery operation>
FIG. 3 shows the flow of hot water in the exhaust heat recovery operation, and the flow path of hot water in the exhaust heat recovery operation is indicated by a bold line. In the exhaust heat recovery operation for recovering the exhaust heat of the fuel cell 4 and heating the hot water in the hot water storage tank 13, the control unit 20 instructs the fuel cell 4 to operate the exhaust heat recovery pump 52. As a result, the hot water in the hot water storage tank 13 exits from the water intake 16 and is connected to the heat recovery pipe (low temperature) 53a, the exhaust heat recovery heat exchanger 51, the heat recovery pipe (high temperature) 53b, and the first three-way valve 21 in the A direction. It circulates in the circulation path which returns to the upper part of the hot water storage tank 13 from the return port 17 via. In addition, since the hot water heated by the exhaust heat recovery heat exchanger 51 and reaching a high temperature reaches the first connection port 21a of the first three-way valve 21, the control unit 20 sets the first three-way valve 21 in the A direction. .

  The hot water is supplied from the water supply port 14 at the lower part of the hot water storage tank 13 and the hot water heated by the exhaust heat recovery operation is returned to the upper part of the hot water storage tank 13, so that the lower part of the hot water storage tank 13 has a low temperature and the upper part has a high temperature. Such a temperature gradient is formed. By continuing the exhaust heat recovery operation, the amount of hot water that accumulates in the upper portion gradually increases.

<Hot-water supply operation>
The hot water storage tank unit 11 may be installed near the bath water heater 70 or may be installed far away. For example, in a house with a bath on the second floor, there are cases where the bath water heater 70 is installed on the outer wall of the second floor and the hot water storage tank unit 11 and the fuel cell 4 are installed on the first floor. The connection pipe (high temperature) 61 and the connection pipe (low temperature) 62 connecting the apparatuses become longer, resulting in an installation situation where the pressure loss is large. In the hot water supply system 10 of the present invention, even in a low water pressure area, even when the piping is long and the pressure loss is large, hot water supply is performed with suppressed increase in pressure loss so that a sufficient amount of hot water can be secured. Yes.

Hot water is supplied in one of the following three control modes.

(1) First mode (tank hot water)
The first mode is a hot water supply operation in the case where the hot water storage tank 13 has sufficiently stored heat. FIG. 4 shows the flow of hot water in the hot water supply operation in the first mode. In the figure, the path through which hot water flows is indicated by a bold line. In the first mode, hot water and hot water from the hot water storage tank 13 are mixed by the mixer 23 to make hot water at a hot water supply set temperature, and hot water is supplied. No water is sent to the bath water heater 70, no heating is performed in the bath water heater 70, and no combustion operation is performed.

  Specifically, the second mixer 23b of the mixer 23 is closed, the opening degree of the first mixer 23a and the third mixer 23c is adjusted, and the outlet side of the mixer 23 detected by the tapping temperature sensor 32 is adjusted. The hot water temperature is controlled so as to become the hot water supply set temperature. Here, for example, the detection temperature of the hot water temperature sensor 18d provided in the hot water storage tank 13 is equal to or higher than the hot water supply set temperature (actually, for example, the hot water supply set temperature + 1 ° C. in consideration of a temperature drop in the hot water supply pipe or the like). In this case, hot water is supplied in the first mode.

(2) Second mode (hot water supply hot water mode)
The second mode is a hot water supply operation when there is no hot water available in the hot water storage tank 13. FIG. 5 shows the flow of hot water in the hot water supply operation in the second mode. In the figure, the path through which hot water flows is indicated by a bold line. In the second mode, hot water heated to a temperature higher than the hot water supply set temperature by the bath water heater 70 and hot water are mixed by the mixer 23 to supply hot water at the hot water supply set temperature.

  Specifically, the second three-way valve 38 is set in the C direction, and water is supplied to the bath water heater 70. Also, the first mixer 23a of the mixer 23 is closed, the opening degree of the second mixer 23b and the third mixer 23c is adjusted, and the hot water on the outlet side of the mixer 23 detected by the hot water temperature sensor 32 is adjusted. The temperature is controlled so as to become the hot water supply set temperature.

  Note that the control unit 20 instructs the bath water heater 70 to provide a hot water temperature so that the hot water temperature of the bath water heater 70 is sufficiently higher than the hot water supply set temperature. Thus, the amount of hot water from the bath water heater 70 necessary for mixing with the water supply to obtain the hot water supply set temperature is reduced, and passes through the connection pipe (low temperature) 62, the bath water heater 70 and the connection pipe (high temperature) 61. The pressure loss caused by this can be kept small. For example, if the hot water supply set temperature is 40 ° C., hot water at 55 ° C. is obtained from the bath water heater 70. If the hot water supply set temperature is 60 ° C., 75 ° C. hot water is obtained from the bath water heater 70.

(3) Third mode (post-mixing hot water mode)
The third mode is a hot water supply operation in the case where heat is stored in the hot water storage tank 13 but the temperature is low and the hot water in the hot water storage tank 13 is not sufficient. FIG. 6 shows the flow of hot water in the hot water supply operation in the third mode. In the figure, the path through which hot water flows is indicated by a bold line. The third mode is selected, for example, when the detected temperature of the hot water temperature sensor 18d of the hot water storage tank 13 is lower than the hot water supply set temperature but not lower than 10 ° C above the hot water supply set temperature.

  In the third mode, the hot water heated by the bath water heater 70, the hot water from the hot water storage tank 13 and the hot water are mixed to make hot water having a hot water supply set temperature. Specifically, hot water produced by heating the second three-way valve 38 in the C direction and heating the hot water in the bath water heater 70, hot water from the hot water storage tank 13 and the hot water from the hot water storage tank 13 are mixed in the hot water supply set temperature. Make hot water and supply hot water. Even if the temperature of the hot water in the hot water storage tank 13 is low, the heat stored in the hot water storage tank 13 can be used up more by mixing with the hot water received from the bath water heater 70, so the first and second Energy savings are higher than when controlling only in the mode.

  The controller 20 preferentially selects the first mode, and hot water that is not lower than the hot water set temperature by a predetermined temperature (for example, 10 ° C.) from the hot water storage tank 13 when hot water at the set temperature cannot be supplied in the first mode. When the supply is possible, the third mode is selected, and when the third mode cannot be selected, the second mode is selected.

<Pouring operation>
FIG. 7 shows the flow of hot water in the pouring operation. In the figure, the path through which hot water flows is indicated by a bold line. In the pouring operation, the hot water on the outlet side of the mixer 23 is supplied to the water supply connection port of the bath water heater 70, and hot water from the hot water storage tank 13 or hot water from the hot water storage tank 13 and hot water are mixed. The hot water at the bath set temperature is poured from the bath water heater 70 to the bath (tub) 2 by adding the heating by the bath water heater 70 to the hot water produced from the outlet side of the mixer 23 or without additional heating. To control.

  Specifically, when pouring (hot water filling) with hot water stored in the hot water storage tank 13, the second three-way valve 38 is set in the D direction, and the hot water and hot water from the hot water storage tank 13 are mixed by the mixer 23. Then, the hot water having the set temperature of the bath is sent to the bath water heater 70 and filled with the pouring circuit of the bath water heater 70. The control unit 20 of the hot water storage tank unit 11 instructs the bath water heater 70 to open the pouring electromagnetic valve 79 while the burner 73 is in the combustion off state. Hot water from the outlet side of the mixer 23 included in the hot water storage tank unit 11 is supplied from a connecting pipe (low temperature) 62 to a hot water supply circuit of the bath water heater 70, that is, a water inlet pipe 74 and a first heat exchange water pipe in the bath water heater 70. After passing through 72 a, the hot water solenoid valve 79, and the connecting pipe 78, the hot water flows out into the bath (tub) 2 through both or one of the bath outlet pipe 77 and the bath return pipe 76 and is poured.

  When the hot water storage tank 13 does not store heat, the second three-way valve 38 is set in the D direction, hot water having a temperature lower than the bath setting temperature in the hot water storage tank 13, water supply, or a bath setting temperature obtained by mixing them. The low temperature hot water is sent to the bath water heater 70, heated to the bath set temperature in the bath water heater 70, and poured through the pouring circuit in the bath water heater 70.

  It should be noted that all the functions used for the fully automatic bath such as detection of water level and reheating use the functions of the bath water heater 70 as they are.

  Thus, since the hot water from the outlet side of the mixer 23 is supplied to the bath water heater 70 by switching the second three-way valve 38 in the D direction, the hot water in the hot water storage tank 13 can be used for pouring. .

<Operation when an earthquake is detected>
FIG. 8 shows the flow of processing relating to the operation corresponding to the occurrence of an earthquake. The control unit 20 includes a detection unit that detects the occurrence of an earthquake. The detection unit may actually detect shaking, or may acquire earthquake occurrence information from outside.

  When the occurrence of an earthquake is detected (step S101; Yes), the control unit 20 acquires information regarding the water level of the bathtub 2 from the bath water heater 70, and determines whether or not the water level of the bathtub 2 has reached a predetermined upper limit water level. (Step S102). When the upper limit water level has not been reached (step S102; No), the hot water in the hot water storage tank 13 is drained to the bathtub 2 (step S103), and the process proceeds to step S105.

  The flow of hot water when the hot water in the hot water storage tank 13 is drained to the bathtub 2 is the same as the pouring operation shown in FIG. In the draining operation to the bathtub 2, hot water accumulated in the upper part of the hot water storage tank 13 is discharged to the bathtub 2 as it is.

  Specifically, the second three-way valve 38 is set in the D direction, the second mixer 23b and the third mixer 23c of the mixer 23 are closed, the first mixer 23a is fully opened, and hot water is supplied from the outlet side of the mixer 23. Is sent to the bath water heater 70, and hot water is filled in the bathtub 2 by the pouring circuit of the bath water heater 70.

  The control unit 20 of the hot water storage tank unit 11 instructs the bath water heater 70 to open the pouring electromagnetic valve 79 while the burner 73 is in the combustion off state. Hot water from the outlet side of the mixer 23 included in the hot water storage tank unit 11 flows out from the connecting pipe (low temperature) 62 through the pouring circuit of the bath water heater 70 to the bath (tub) 2 and is poured.

  As a result, the hot water storage tank 13 is replenished with water from the lower water supply port 14 and the hot water in the hot water storage tank 13 is replaced with cold water.

  In step S102, when the water level of the bathtub 2 reaches the upper limit water level (step S102; Yes), the hot water in the hot water storage tank 13 is drained to the outside (step S104), and the process proceeds to step S105.

  FIG. 9 shows a case of draining to the outside, and the thick line in the figure indicates the water flow path. Hot water flowing out from the hot water outlet 15 at the top of the hot water storage tank 13 is drained from the drain pipe 41 to the outside.

  Specifically, the second three-way valve 38 is set in the D direction, the third three-way valve 43 is set in the F direction, the second mixer 23b and the third mixer 23c of the mixer 23 are closed, and the first mixer 23a is closed. As fully opened, hot water from the outlet side of the mixer 23 is drained from the drain pipe 41 to the outside.

  In step S105, the control unit 20 determines whether or not the entire hot water storage tank 13 has become cold water and the replacement has been completed. Here, when the detected temperature of the tank upper temperature sensor 18e and the detected temperature of the first temperature sensor 18a or the feed water temperature sensor 35 become the same temperature (or a temperature difference within a certain range), it is determined that the replacement is completed.

  If the replacement is not completed (step S105; No), the process returns to step S102, and drainage to the bathtub 2 (step S103) or drainage to the outside (step S104) is continued.

  If the replacement is completed (step S105; Yes), the drainage is stopped (step S106), and the process is terminated.

  Thus, when the occurrence of an earthquake is detected, the hot water stored in the hot water storage tank 13 is drained to the bathtub 2 and the like, and the hot water storage tank 13 is replaced with cold water. Even in this case, the exhaust heat of the fuel cell 4 can be recovered with the cold water in the hot water storage tank 13 and the operation of the fuel cell 4 can be continued. After the occurrence of an earthquake, a power failure often occurs. Therefore, it is useful to replace the hot water storage tank 13 with cold water before the water break so that the self-sustaining power generation of the fuel cell 4 can be continued for a long time.

  Further, when the hot water in the hot water storage tank 13 is drained to the bathtub 2, bathing is possible even if the water is cut off. In particular, since hot water in the hot water storage tank 13 is drained and stored in the bathtub 2, it is possible to take a warm bath even when the supply of gas is stopped thereafter. Moreover, if a throw-in type electric heater is used, the hot water in the bathtub 2 can be maintained at a temperature at which bathing is possible for a long period of time.

  The embodiment of the present invention has been described with reference to the drawings. However, the specific configuration is not limited to that shown in the embodiment, and there are changes and additions within the scope of the present invention. Are also included in the present invention.

  As long as the hot water storage system of the present invention includes the hot water storage tank unit 11 of the bath hot water system, the exhaust heat recovery device 50, the bath water heater 70, and the fuel cell 4 may or may not be included. The exhaust heat recovery device 50 may be included in the fuel cell 4, or the bath water heater 70 may be an existing one.

  In the embodiment, the backup heat source machine is the bath water heater 70 of the type that burns the burner 73, but is not limited to this.

  The configuration of the hot water storage tank unit 11 is not limited to that illustrated in the embodiment. For example, in the embodiment, the hot water from the bath water heater 70 is returned to the mixer 23 and can be mixed. However, in the mixer 23, the hot water and hot water from the hot water storage tank 13 are mixed and bath hot water is supplied. The hot water from the bath water heater 70 may be supplied to the hot water tap as it is.

  In the embodiment, in the draining operation to the bathtub 2 after the occurrence of the earthquake, an example in which additional heating is not performed by the bath water heater 70 is shown. However, the temperature of the hot water supplied from the hot water storage tank 13 satisfies, for example, the bath set temperature. If there is no gas supply and the gas supply is not stopped, additional heating may be performed by the bath water heater 70 so that hot water having a bath set temperature (or higher temperature) is filled in the bathtub 2. . Even if the gas supply is stopped later, it becomes easy to take a warm bath.

  In the embodiment, the drainage to the bathtub 2 is given priority, and when the drainage to the bathtub 2 cannot be performed, the drainage is performed to the outside. However, for the purpose of ensuring the operation of the fuel cell 4, the drainage destination is only the outside, It may be configured to drain everything from the beginning.

2 ... Bath (tub)
4 ... Heat source machine (fuel cell)
DESCRIPTION OF SYMBOLS 10 ... Bath hot water supply system 11 ... Hot water storage tank unit 12 ... Water supply pipe 13 ... Hot water storage tank 14 ... Water supply port 15 ... Outlet 16 ... Water intake 17 ... Return port 18a ... First temperature sensor 18b ... Second temperature sensor 18c ... Third Temperature sensor 18d ... Hot water temperature sensor 18e ... Tank upper temperature sensor 20 ... Control unit 21 ... First three-way valve 21a ... First connection port of the first three-way valve 21b ... Second connection port of the first three-way valve 21c ... First Third connection port of three-way valve 22a ... Heat recovery pipe high temperature side temperature sensor 22b ... Heat recovery pipe low temperature side temperature sensor 23 ... Mixer 23a ... First mixer 23b ... Second mixer 23c ... Third mixer 24 ... Excessive Pressure relief valve 25 ... Intake valve 26 ... Tank outlet temperature sensor 28 ... Connecting pipe high temperature side temperature sensor 29 ... Hot water supply high temperature sensor 31 ... Hot water supply pipe 31b ... Pipe 32 ... Hot water temperature sensor 33 ... High cut temperature sensor 34 ... Flow rate sensor 35 ... Feed water temperature sensor 36 ... Pressure reducing valve 37a ... Check valve 37b ... Check valve 37c ... Check valve 38 ... Second three-way valve 38a ... First connection of second three-way valve Port 38b ... Second connection port of the second three-way valve 38c ... Third connection port of the second three-way valve 39 ... Check valve 41 ... Drain pipe 42 ... Drain plug 43 ... Third three-way valve 43a ... Third three-way valve DESCRIPTION OF SYMBOLS 1 Connection port 43b ... 2nd connection port of 3rd three-way valve 43c ... 3rd connection port of 3rd three-way valve 50 ... Waste heat recovery apparatus 51 ... Waste heat recovery heat exchanger 52 ... Waste heat recovery pump 53 ... Heat recovery piping 53a ... Heat recovery piping (low temperature)
53b ... Heat recovery piping (high temperature)
54 ... Bypass pipe 61 ... Connection pipe (high temperature)
62 ... Connection piping (low temperature)
70 ... Bath water heater 72 ... Heat exchanger 72a ... First heat exchange water pipe 72b ... Second heat exchange water pipe 73 ... Burner 73a ... Gas supply pipe 74 ... Inlet pipe 75 ... Outlet pipe 76 ... Bath return pipe 77 ... Bath return pipe 77 78 ... Connecting pipe 79 ... Pouring solenoid valve 81 ... Water volume servo 82 ... Outflow temperature sensor 83 ... Bypass pipe 84 ... Bypass adjustment valve 85 ... Flow sensor 86 ... Incoming water temperature sensor 87 ... Bath circulation pump 88 ... Flow water switch 89a ... Bath going out Temperature sensor 89b ... Bath return temperature sensor 91 ... Control unit 92 ... Remote control (common remote control)

Claims (3)

A hot water storage system that includes hot water storage tanks that store hot water supplied to hot water and that is replenished with clean water so that the water becomes full, recovering the exhaust heat of the fuel cell and raising the temperature of the water in the hot water storage tank,
A drainage section for draining hot water in the hot water storage tank;
Regardless of whether or not the hot water storage tank is full when an earthquake is detected , the drainage unit is operated, the hot water in the hot water storage tank is drained and replaced with clean water, and
A hot water storage system characterized by comprising: The hot water storage system according to claim 1, wherein the drainage unit drains hot water in the hot water storage tank into a bathtub. The hot water storage tank is provided with a supply port for clean water at the bottom,
The hot water storage system according to claim 1 or 2, wherein the drainage part drains hot water in the hot water storage tank from an upper part of the hot water storage tank.

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