JP6286312B2 - 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.

  Household fuel cells generate electricity using city gas or propane gas as fuel, and the fuel cell cannot generate electricity when the gas supply is stopped. Therefore, in a hot water storage system in which the water stored in the hot water storage tank is heated with the exhaust heat of the fuel cell to supply hot water, if the gas supply is stopped, the water in the hot water storage tank cannot be heated with the exhaust heat of the fuel cell. .

  In the hot water storage system, when the temperature of the hot water in the hot water storage tank is lower than the set temperature, the hot water supplied from the hot water storage tank is heated by a backup heat source device when the hot water is discharged. When a gas-fired water heater is used for the backup heat source device, heating by the backup heat source device cannot be performed when the gas supply is stopped.

  Therefore, in a hot water storage system that raises the temperature of the water in the hot water storage tank with the exhaust heat of the fuel cell and uses a gas combustion type hot water heater as a backup heat source, hot water can be made when the gas supply is stopped. Disappear. However, even in this situation, if the user opens the faucet, the hot water in the hot water storage tank can be used.

  By the way, when the temperature of the hot water in the hot water storage tank is higher than the set temperature, the hot water storage system mixes the hot water and the feed water from the hot water storage tank with a mixer and then sends the hot water to the back-up heat source machine. Since the mixer is usually electrically driven, the mixing ratio cannot be adjusted in the event of a power failure.

  Therefore, when the user opens the faucet with both gas and electricity stopped, the hot water in the hot water storage tank is mixed with the water supply at the mixing ratio at the time of power failure. Therefore, if the ratio of the water supply in the mixing ratio at the time of a power failure is high, even if hot water is in the hot water storage tank, only warm water or water close to the water supply temperature can be used.

  In order to eliminate the inconvenience that the mixing ratio of the mixer cannot be changed during a power failure, Patent Document 1 describes that during the power failure, the mixer or the like is moved by power supply from an auxiliary power source to make hot water having a set temperature. A mixing device is disclosed.

JP 62-242734 A

  In the apparatus disclosed in Patent Document 1, since the mixer is always controlled by the battery while the hot water is being discharged, the battery is heavily consumed.

  The present invention is intended to solve the above-described problem, and in a situation where gas and electricity are stopped, a hot water storage system that can discharge hot water in a hot water storage tank at an appropriate temperature while suppressing battery consumption. The purpose is to provide.

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

[1] A hot water storage system comprising a hot water storage tank for collecting hot water heated by recovering the exhaust heat of the fuel cell and mixing hot water obtained from the hot water storage tank with hot water obtained from the hot water storage tank using a mixer There,
A control unit for controlling the mixing ratio of the mixer;
A detection unit for detecting gas supply stoppage and power failure;
Battery,
Have
The control unit drives the mixer with the battery when the gas supply is stopped and a power failure occurs so that the ratio of hot water from the hot water storage tank in the mixing ratio of the mixer becomes a predetermined value or more. Hot water storage system characterized by setting.

  In the above invention, when the supply of gas and electricity is stopped, the mixer is driven by the battery, and the mixing ratio is set so that the ratio of hot water from the hot water storage tank becomes a predetermined value or more. Mixing taps that can mix hot water and water supply are popular in the home. Therefore, if hot water is discharged from the hot water storage system as much as possible, the hot water at a desired temperature can be discharged by mixing the feed water with the mixing tap at the end. Also, since the mixer only needs to be driven once after a power failure, battery consumption is low.

[2] The hot water storage system according to [1], wherein the predetermined value is 100%.

  In the said invention, the hot water of a hot water storage tank comes out of a mixer as it is, without mixing water supply.

  According to the hot water storage system according to the present invention, it is possible to discharge the hot water in the hot water storage tank at an appropriate temperature while suppressing the exhaustion of the battery in a state where gas and electricity are stopped.

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 pouring operation | movement. It is a flowchart which shows corresponding | compatible operation | movement when both gas and electricity stop. It is explanatory drawing which shows the flow of the hot water at the time of discharging hot water in the condition where both gas and electricity stopped. It is a figure which shows an example of the circuit which drives a mixer.

  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 heat source unit 4, an exhaust heat recovery device 50, and a bath water heater 70 as a backup heat source unit. In this example, the heat source unit 4 is a fuel cell. In the figure, piping between apparatuses and 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 in the heat source unit 4 or the like and recovers the exhaust heat of the heat source unit 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. Each of the first mixer 23a, the second mixer 23b, and the third mixer 23c has a structure in which a valve is opened and closed by an electric gear motor.

  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. A water faucet 8 or the like that can mix hot water and hot water from the hot water storage tank unit 11 at an arbitrary mixing ratio is attached to the tip of the hot water supply pipe 31 outside the hot water storage tank unit 11. The mixing faucet 8 is widely used as a faucet attached to a bath, kitchen, wash basin, etc. in a general household.

  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 check valve 39 is 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.

  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 heat source unit 4 and the bath water heater 70.

  The control unit 20 has a function of detecting a gas supply stop and a power failure. The method for detecting the gas supply stop and the method for detecting a power failure may be arbitrary. The stop of gas supply may be detected by the hot water storage tank unit 11, or information regarding the stop of gas supply may be acquired from the fuel cell 4 or the bath water heater 70.

  The hot water storage tank unit 11 includes a battery (not shown) in preparation for a power failure. The battery is used when power supply to both the commercial power source and the fuel cell 4 is stopped. Here, the state where the supply of power from both the commercial power source and the fuel cell 4 is stopped is regarded as a power failure. The hot water storage tank unit 11 receives power supply from the fuel cell 4 without using the battery when the fuel cell 4 is generating power even if power supply from the commercial power source is interrupted.

  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, a function of heating a heating medium fluid by flowing a heated heat medium fluid, and the like. 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 heat source unit 4 and heating the hot water in the hot water storage tank 13, the control unit 20 instructs the heat source unit 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 is a case 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 heat source unit 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 can be used for pouring.

<Operation when supply of gas and electricity is stopped>
FIG. 8 shows an operation performed to enable hot water having a proper temperature to be discharged when the supply of gas and electricity is stopped.

  The control unit 20 monitors whether or not the gas supply is stopped and a power failure occurs (step S101). When the gas supply is stopped and a power failure occurs, the mixer 23 is driven by the electric power supplied from the battery, and the mixer 23 is set so that the mixing ratio is 100% of the hot water from the hot water storage tank 13. (Step S102). After that, the mixing ratio of the mixer 23 is not changed at least during the gas supply and power outage.

  FIG. 9 shows the flow of hot water in the operation of supplying hot water while the supply of gas and electricity is stopped. In the operation, the mixer 23 sends only hot water from the hot water storage tank 13 to the hot water supply pipe 31.

  Specifically, the second mixer 23b and the third mixer 23c of the mixer 23 are fully closed, and the first mixer 23a is fully opened. When the user opens the mixing tap 8 provided at the end of the hot water supply pipe 31, hot water is supplied from the hot water outlet 15 of the hot water storage tank 13 at a pressure at which water is supplied from the water supply pipe 12 to the water supply opening 14 of the hot water storage tank 13. Get out. Since hot water accumulates in the upper part of the hot water storage tank 13, the hot water flows out of the hot water storage tank 13.

  The hot water discharged from the hot water outlet 15 of the hot water storage tank 13 passes through the mixer 23 without being mixed with the feed water in the mixer 23, and is provided at the tip of the hot water supply pipe 31 via the hot water supply pipe 31. It flows out from the mixing tap 8. The user can mix hot water from the hot water storage tank unit 11 with the hot water from the hot water storage tank unit 11 as appropriate, and make hot water at a desired temperature (temperature lower than the temperature of hot water supplied from the hot water supply pipe 31).

  In this way, when the supply of gas and electricity stops, the hot water storage tank unit 11 is accumulated in the hot water storage tank 13 if the mixing ratio of the mixer 23 is set so that the hot water from the hot water storage tank 13 becomes 100%. The hot water can be sent out toward the mixing tap 8 at the end without lowering the temperature of the hot water. Since the hot water temperature can be lowered by the mixing tap 8 at the end, hot water having a temperature as high as possible is sent out from the hot water storage tank unit 11, and hot water having an arbitrary temperature below that temperature is made and discharged from the mixing tap 8. Is possible.

  Moreover, if the mixing ratio of the mixer 23 is changed only once at the beginning when the supply of gas and electricity is stopped, the mixing ratio of the mixer 23 does not need to be changed thereafter. Such power consumption can be reduced.

  In addition, the circuit which drives the mixer 23 may be comprised with a circuit as shown in FIG. 10, for example. In the mixer 23 shown in FIG. 10, a mixing ratio (opening degree) is changed by displacing a predetermined mechanical component by the stepping motor 101.

  The circuit shown in FIG. 10 includes a control unit 20 that controls the driving of the stepping motor 101 of the mixer 23 in a normal state where AC 100 V is supplied, a detection circuit 103 that detects that the supply of AC 100 V has stopped, and this detection. An emergency drive circuit 105 that drives the stepping motor 101 with the power supplied from the battery 104 when the circuit 103 detects the supply stop of AC 100V is provided. For the detection circuit 103, for example. Use a normally closed relay that closes the contacts when the power is off.

  The stepping motor 101 is connected with four power lines (or four or more) for driving and three signal lines (fully open, fully closed, com). Specifically, all power lines and three signal lines are connected from the CPU of the control unit 20. On the other hand, from the emergency drive circuit 105, all power lines and fully open signal lines are connected.

  The stepping motor 101 of the mixer 23 energizes one pulse to the coil in the open direction with respect to the coil corresponding to the current position among the coils corresponding to the four power lines for driving (the ground uses the signal line com). Then, the coil moves in the opening direction, and when one pulse is applied to the coil in the closing direction with respect to the coil corresponding to the current position, the coil moves in the closing direction. If the coil corresponding to the current position is the first coil and the coil in the opening direction is the second coil, the third coil and the fourth coil hereinafter, the stepping motor 101 is located at the current position (first coil position). From No. 2 coil pulse energization → No. 3 coil pulse energization → No. 4 coil pulse energization → No. 1 coil pulse energization → No. 2 coil pulse energization Driving power (pulses) to four power lines corresponding to adjacent positions ) Is moved to the next position each time, and the mixing ratio of the mixer 23 can be changed by a predetermined amount in the fully open direction. When the fully open position is reached, a fully open signal is issued, and energization is stopped to prevent step-out. Conversely, from the current position (1st coil position), 4th coil pulse energization → 3rd coil pulse energization → 2nd coil pulse energization → 1st coil pulse energization → 4th coil pulse energization corresponds to the adjacent position. Each time a pulse is sent to the four power lines, it moves to the next position, and the mixing ratio of the mixer 23 can be changed by a predetermined amount in the fully closed direction. When the fully closed position is reached, a fully closed signal is issued, and energization is stopped to prevent step-out.

  In the normal state in which AC100V is supplied, the CPU of the control unit 20 obtains by calculation how much driving power (number of pulses) has been sent via the power line after the fully closed signal or fully opened signal is turned on. Thus, the current opening degree of the mixer 23 is recognized. For example, the current mixture ratio (opening degree) is calculated from the number of pulses obtained by subtracting the number of pulses given in the fully closed direction from the number of pulses given in the fully opened direction from the fully closed position.

  In order to change the mixer 23 to the target opening degree, the number of pulses to be generated in the fully open direction or the fully closed direction is calculated from the current opening degree and the target opening degree. It is necessary to give the number of pulses shown to the stepping motor 101. When the supply of AC 100 V is stopped, the information indicating the current opening calculated by the CPU is lost, so the above calculation cannot be performed, and the mixer 23 cannot be controlled to the target opening.

  However, as shown in FIG. 8, when the gas supply is interrupted and a power failure occurs, the mixer 23 may be fully opened. Therefore, when the supply of AC 100V is stopped, the emergency drive circuit 105 generates a predetermined number of pulses that can be fully opened even if the current opening of the mixer 23 is fully closed. Regardless of the case, the stepping motor 101 is uniformly supplied. Specifically, a predetermined number of pulses equal to or greater than the number of pulses necessary for switching from fully closed to fully open are output to the stepping motor 101 in the fully open direction.

  Thus, the opening degree of the mixer 23 can be reduced in accordance with a power failure without providing a calculation function such as a CPU or a function for storing the current opening degree, and without connecting a signal line provided from the stepping motor 101. It can be set in the fully open state, that is, so that the hot water from the hot water storage tank 13 becomes 100%.

  For example, when the current opening is an intermediate opening or is substantially fully open, an excessive number of pulses is given to the stepping motor 101 from the emergency drive circuit 105 due to a power failure. Although the stepping motor 101 is in a step-out state due to this extra pulse, there is no problem because the CPU executes a sequence for returning from the step-out state to the normal state when the AC100V energization is resumed. As a sequence for returning from the step-out state to the normal state, for example, once the stepping motor 101 is continuously driven in the fully closed direction and the current position is initialized when the fully closed signal indicating that the fully closed position is reached is received. There is control such as grasping the current opening. By performing this sequence, the stepping motor 101 is returned from the step-out state to the normal state.

  Further, the detection circuit 103 notifies the emergency drive circuit 105 of the power failure (drives the emergency drive circuit 105) after a predetermined time has elapsed since the power failure. For example, a relay whose contact is made after a lapse of a predetermined time (several seconds) after the power is turned off is used as the detection circuit 103. This prevents the emergency drive circuit 105 from operating due to a phenomenon such as an instantaneous power failure.

  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.

  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.

  When the supply of gas and electricity stops, the mixing ratio of the mixer 23 is set so that the hot water from the hot water storage tank 13 becomes 100%, but the mixing ratio is not limited to this. For example, when the hot water temperature in the hot water storage tank 13 is 80 ° C., for example, the hot water temperature from the hot water storage tank unit 11 may be set to a mixing ratio that decreases to about 60 ° C.

  In the embodiment, the state where the supply of power from both the commercial power source and the fuel cell 4 is stopped is regarded as a power failure. However, when the hot water storage tank unit 11 does not receive the power supply from the fuel cell 4, A power failure may be caused by stopping the power supply.

  The hot water storage tank unit 11 provides a button on the remote control 92 or the like to be operated by the user when the gas supply is stopped and a power failure occurs, and that the gas and electricity supply is stopped when the button is pressed. You may make it recognize.

2 ... Bath (tub)
3 ... Heating radiator 8 ... Mixing tap 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)
DESCRIPTION OF SYMBOLS 101 ... Stepping motor 103 ... Detection circuit 104 ... Battery 105 ... Emergency drive circuit

Claims (2)

A hot water storage system comprising a hot water storage tank for collecting hot water heated by recovering exhaust heat of the fuel cell, and mixing hot water obtained from the hot water storage tank with hot water supplied from the hot water storage tank, using a mixer,
A control unit for controlling the mixing ratio of the mixer;
A detection unit for detecting gas supply stoppage and power failure;
Battery,
Have
The control unit drives the mixer with the battery when the gas supply is stopped and a power failure occurs so that the ratio of hot water from the hot water storage tank in the mixing ratio of the mixer becomes a predetermined value or more. Hot water storage system characterized by setting. The hot water storage system according to claim 1, wherein the predetermined value is 100%.

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