JP2016038114A - Hot water storage system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To use hot water by heating water in a hot water storage tank even when gas supply is stopped and a fuel battery cannot generate power, in a hot water storage system in which water in the hot water storage tank is heated by recovering exhaust heat of the fuel battery.SOLUTION: Stop of gas supply to a fuel battery is determined when a heat storage amount of a hot water storage tank is less than a prescribed upper limit amount to stop an operation of the fuel battery, and a water temperature in a circulation pipe conduit for recovering exhaust heat indicates temperature change corresponding to natural heat radiation, or the stop of gas supply to the fuel battery is determined when the heat storage amount of the hot water storage tank is less than the prescribed upper limit amount, and ignition error occurs in a gas combustion type heat source machine for additionally heating the hot water supplied from the hot water storage tank in supplying hot water. When the gas supply is stopped, hot water/water in the hot water storage tank is heated by an electric heater of the fuel battery.SELECTED DRAWING: Figure 8

Description

  The present invention relates to a hot water storage system in which hot water in a hot water storage tank is collected by collecting exhaust heat from a power generation device such as a fuel cell and heating the hot water.

  Due to disasters, lifelines such as electricity, gas, and water supply may stop. For example, since a household fuel cell generates power using city gas or propane gas as fuel, if the gas supply is stopped due to a disaster, power generation cannot be continued.

  In addition, in a hot water storage system that recovers exhaust heat from the fuel cell and raises the temperature in the hot water storage tank, if the fuel cell operation is stopped for a long time, the water temperature in the hot water storage tank may drop and Legionella bacteria may be generated. There is. Patent Document 1 discloses a fuel cell system in which an electric heater is driven by a commercial power source to sterilize a hot water storage tank when the fuel cell does not operate for a predetermined time or longer.

  Also, in a hot water storage system that heats the water in the hot water storage tank by circulating it through a circulation circuit that passes through a heat exchanger for recovering the exhaust heat of the fuel cell, when the system power supply fails, the power generated by the fuel cell Is controlled to be supplied to an electric heater provided in a circulation circuit to raise the temperature of the circulating hot water (see Patent Document 2).

JP 2009-64753 A JP 2007-272158 A

  The following problems arise when water breakage occurs. 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, the hot water in the hot water storage tank cannot be discharged from the faucet.

  In order to use the hot water in the hot water storage tank when the water is shut off, it is conceivable to provide a drain valve at the lower part of the hot water storage tank. However, hot water accumulates in the upper part of the hot water tank, and the temperature is lower in the lower part of the hot water tank, so if the entire hot water tank is not hot, only cold water will come out even if you open the drain valve at first. You cannot use hot water.

  Further, the discharged water cannot be used for recovering the exhaust heat of the fuel cell. If all the cold water below the hot water storage tank is discharged from the drain valve and used, the exhaust heat of the fuel cell cannot be recovered, and as a result, the power generation of the fuel cell is stopped. In the event of a power outage in addition to water outage due to a disaster or the like, the fuel cell becomes an important power source, so it is not preferable to stop its operation.

  An object of the present invention is to provide a hot water storage system that can use the water in a hot water storage tank as hot water in the event of a water outage.

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

[1] A hot water storage system for recovering the temperature of water in a hot water storage tank for storing hot water to be used for tapping hot water by recovering exhaust heat of a predetermined power generator,
A heat exchanger for recovering the exhaust heat;
A circulation line having a start end connected to a water intake at a lower portion of the hot water storage tank, via the heat exchanger, and an end connected to a return opening at an upper portion of the hot water storage tank;
A circulation pump for circulating the water in the hot water storage tank through the circulation line;
A drain port that is provided in the circulation line downstream from the heat exchanger and the circulation pump and is manually opened and closed;
A sensor for detecting the open / closed state of the drain;
When the sensor detects an open state of the drain, a control unit that operates the circulation pump;
A hot water storage system characterized by comprising:

  In the above invention, when the drain outlet is manually opened in the event of a water interruption or the like, the circulating water that circulates the hot water in the hot water storage tank through the circulation line that passes through the heat exchanger for recovering the exhaust heat of the power generator such as the fuel cell. Force the pump to run. Thereby, the water in the hot water storage tank is extracted from the water intake port at the lower part of the hot water storage tank, and is discharged from the drain port through the heat exchanger for recovering the exhaust heat of the power generator such as the fuel cell. Thereby, at the time of a water stop, the hot water heated up with the exhaust heat of power generators, such as a fuel cell, can be discharged | emitted from a drain outlet.

[2] An electric heater for raising the temperature of water passing through the circulation pipe is further provided,
The hot water storage system according to [1], wherein the control unit operates the electric heater when the sensor detects an open state of the drain port.

  In the said invention, when a drain outlet is opened manually at the time of a water stop etc., a circulation pump and an electric heater will be forcedly operated. Thereby, the hot water heated by the electric heater can be discharged from the drain port.

[3] Hot water storage that raises the temperature of the water in the hot water storage tank for storing hot water to be supplied to the hot water by recovering the exhaust heat of a predetermined power generator equipped with a heat exchanger for exhaust heat recovery and a circulation pump A system,
A circulation line having a start end connected to a water intake at a lower part of the hot water storage tank, via the heat exchanger and the circulation pump, and an end connected to a return port at an upper part of the hot water storage tank;
A drain port provided in the circulation line downstream of the heat exchanger and the circulation pump and manually opened and closed;
A sensor for detecting the open / closed state of the drain;
A control unit that instructs the fuel cell to operate the circulation pump when the sensor detects an open state of the drain;
A hot water storage system characterized by comprising:

  In the above invention, when the drain outlet is manually opened at the time of water interruption or the like, the circulation pump included in the power generation device such as a fuel cell is forcibly operated. Thereby, the water in the hot water storage tank is extracted from the water intake port at the lower part of the hot water storage tank, and is discharged from the drain port through the heat exchanger for recovering the exhaust heat of the power generator such as the fuel cell. Thereby, at the time of a water stop, the hot water heated up with the exhaust heat of power generators, such as a fuel cell, can be discharged | emitted from a drain outlet.

[4] The predetermined power generation device further includes an electric heater that raises the temperature of water sent by the circulation pump,
The hot water storage system according to [3], wherein the control unit instructs the fuel cell to operate the electric heater when the sensor detects an open state of the drain port. .

  In the above invention, when the drain outlet is manually opened at the time of water interruption or the like, the circulation pump and the electric heater included in the power generation device such as a fuel cell are forcibly operated. Thereby, the hot water heated by the electric heater can be discharged from the drain port.

[5] The hot water storage system according to any one of [1] to [4], further including an air intake portion that takes in air from an upper portion of the hot water storage tank when hot water flows out from the drain port.

  In the said invention, the pressure fall in the hot water storage tank accompanying drainage can be prevented, and smooth drainage is maintained.

[6] The hot water storage system according to any one of [1] to [5], wherein the predetermined power generation device is a fuel cell.

  According to the hot water storage system according to the present invention, the water in the hot water storage tank can be used as hot water when water breakage occurs.

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 the operation | movement accompanying opening and closing of an emergency intake valve. It is a figure which shows a water flow path | route when the emergency water intake valve is open.

  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 as a heat source unit, and a bath water heater 70 as a backup heat source unit that additionally heats the hot water supplied from the hot water storage tank unit at the time of hot water. The The fuel cell 4 has a built-in exhaust heat recovery device 50 for recovering the exhaust heat of the fuel cell 4. 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 a capacity of about 100 liters, for example. In the hot water storage tank 13, a first temperature sensor 18 a that detects the water temperature at a water level of 20 liters from the bottom has a second temperature that detects the water temperature at that position at a water level of 40 liters from the bottom. The third temperature sensor 18c, which detects the water temperature at the 60 liter water level from the bottom, detects the water temperature at that location at the 80 liter water level from the bottom. However, a tank upper temperature sensor 18e for detecting the water temperature at the location is provided at almost the top of the hot water storage tank 13, respectively.

  The exhaust heat recovery device 50 includes a primary circulation circuit 56 in which the temperature of the internal heat medium fluid is increased by the exhaust heat of the fuel cell 4. The primary circulation circuit 56 is provided with a pump 57 that circulates the heat medium fluid to the primary circulation circuit 56 and an electric heater 58 for heating the heat medium fluid that circulates in the primary circulation circuit 56.

  Further, the exhaust heat recovery device 50 includes an exhaust heat recovery heat exchanger 51 for exchanging heat between the heat medium fluid passing through the primary circulation circuit 56 and hot water circulating in the exhaust heat recovery circulation path, and an exhaust heat recovery pump. 52. The hot water storage tank 13 and the exhaust heat recovery heat exchanger 51 are connected by a heat recovery pipe 53 (53a, 53b) so that an exhaust heat recovery circulation path for circulating the water in 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 heat recovery pipe (low temperature) 53 a is connected to the inlet side of the secondary water pipe 51 a of the exhaust heat recovery heat exchanger 51. Are connected at the other end. The exhaust heat recovery pump 52 is inserted in a heat recovery pipe (low temperature) 53a near the entrance side of the secondary water pipe 51a, and the exhaust heat recovery pump 52 stores the water in the heat recovery pipe (low temperature) 53a in a hot water storage tank. Water is fed from the 13 water intake 16 side toward the entrance side of the secondary water pipe 51 a of the exhaust heat recovery heat exchanger 51.

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

  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. The heat recovery pipe low temperature side temperature sensor 22b is provided in the heat recovery pipe (low temperature) 53a from the water intake 16 of the hot water storage tank 13 to the junction with the bypass pipe 54.

  An emergency water intake valve 44 is provided in the middle of the pipe connecting the second connection port 21 b of the first three-way valve 21 and the return port 17 of the hot water storage tank 13. The emergency water intake valve 44 is a manual three-way valve. The first connection port 44a of the emergency intake valve 44 communicates with the first connection port 21a of the first three-way valve 21, the second connection port 44b communicates with the return port 17, and the third connection port 44c is released. It has become. The emergency intake valve 44 has a closed state in which the first connection port 44a and the second connection port 44b communicate with each other and the third connection port 44c is closed, and the first connection port 44a and the third connection port 44c communicate with each other. The two connection ports 44b can be manually switched to the closed state. Normally closed.

  The emergency intake valve 44 is provided with an open / close sensor for detecting whether the emergency intake valve 44 is in a closed state or an open state. The control unit 20 recognizes whether the emergency intake valve 44 is open or closed from the output of the open / close sensor.

  The pipe connecting the third connection port 44c of the emergency intake valve 44 and the return port 17 of the hot water storage tank 13 branches in the middle, and a vacuum breaker 45 is attached to the branch destination. The vacuum breaker 45 functions as an air intake portion that takes in outside air when the return port 17 side becomes negative pressure.

  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 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 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, 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 in which the exhaust heat of the fuel cell 4 is recovered and the hot water in the hot water storage tank 13 is heated, the control unit 20 instructs the fuel cell 4 to provide the pump 57 and the exhaust heat recovery pump 52 of the primary circulation circuit 56. Is activated. As a result, the heat medium fluid circulates in the primary circulation circuit 56, and the hot water in the hot water storage tank 13 comes out of the water intake port 16, and the heat recovery pipe (low temperature) 53a, the exhaust heat recovery heat exchanger 51, the heat recovery pipe ( It circulates in a circulation path returning from the return port 17 to the upper part of the hot water storage tank 13 via the first three-way valve 21 in the A direction. In addition, the hot water that has been absorbed by heat exchange in the exhaust heat recovery heat exchanger 51 from the heat medium fluid circulating in the primary circulation circuit 56 reaches the first connection port 21a of the first three-way valve 21. Therefore, 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) 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.

  Next, an emergency hot-water supply function that supplies hot water in the hot water storage tank 13 when hot water is supplied will be described.

  The hot water storage tank unit 11 is provided with an emergency hot water discharge function that causes the water in the hot water storage tank 13 to flow out of the third connection port 44c of the emergency water intake valve 44 in preparation for the time of water interruption. When the user wants to use hot water using this function, the emergency intake valve 44 is switched to the open state.

  FIG. 8 shows a flow of operations related to the emergency hot water supply function. The controller 20 monitors the open / close state of the emergency intake valve 44 (step S101), and when the emergency intake valve 44 is manually opened (step S101; Yes), the fuel cell 4 is The forced operation of the electric heater 58, the exhaust heat recovery pump 52, and the pump 57 is instructed (step S102).

  Usually, an exhaust heat recovery pump 52 that circulates hot water from the hot water storage tank 13 in order to recover the exhaust heat from the fuel cell 4 (the electric heater 58 is OFF) depends on the temperature of water taken in from the intake port 16. Control is performed to vary the ability. For example, when the temperature of water taken in from the water intake 16 of the hot water storage tank 13 is low (for example, at 15 ° C.), the fuel cell 4 is sufficiently cooled (primary circulation circuit) even if the flow rate circulated by the exhaust heat recovery pump 52 is small. The exhaust heat recovery pump 52 is driven with a low capacity (for example, 0.2 to 0.3 liter per minute). As a result, hot (for example, 60 degup 70 to 80 ° C.) hot water returns to the return port 17 of the hot water storage tank 13. For example, the upper side of the hot water storage tank 13 has hot water of 70 to 80 ° C., but the lower side has such an operation state when there is water of 15 ° C.

  In addition, for example, full storage (a state where the amount of heat stored in the hot water storage tank 13 reaches a predetermined upper limit and the exhaust heat recovery of the fuel cell can no longer be performed) becomes closer, and the temperature of the water taken out from the water intake 16 becomes higher. In such a case (for example, up to 45 ° C.), the driving capacity of the exhaust heat recovery pump 52 is increased to increase the circulating flow rate (for example, 1 liter per minute of the maximum capacity), and the maximum capacity of the exhaust heat recovery pump 52 is exceeded. However, if it is determined that the temperature of the water taken out from the water intake 16 is high (for example, when the temperature exceeds 45 ° C.), the operation of the fuel cell 4 is stopped. Yes.

  By the way, if it is not fully stored, if the drain plug 42 is opened, any amount of cold water can be taken out. Therefore, the temperature of the hot water coming out of the emergency intake valve 44 is, for example, as high as possible, such as 60 ° C. Therefore, there are many choices that can be made to the desired hot water temperature, which is preferable. However, if the flow rate to be taken out is 0.2 to 0.3 liters per minute, it takes too much time to take out hot water.

  Therefore, in the hot water storage system 10 according to the present embodiment, the exhaust heat recovery pump 52 is operated at the maximum capacity (for example, 1 liter of maximum capacity per minute) regardless of the temperature of the water taken out from the water intake 16 of the hot water storage tank 13. Thus, the amount of hot water taken out from the emergency water intake valve 44 is increased, and in order to prevent the hot water temperature from being lowered as much as possible, additional heating is performed using the electric heater 58.

  However, the operation of the fuel cell 4 is stopped when it is determined that the temperature of the water taken out from the intake port 16 is high enough that the cooling becomes insufficient even if the maximum capacity of the exhaust heat recovery pump 52 is exceeded. I give priority. Therefore, in this case, only the electric heater 58 is heated (for example, 55 ° C. = 45 ° C. + 10 degup) with respect to the water (for example, 45 ° C.) taken out from the water intake 16, or sufficient water is taken out from the water intake 16. When the temperature is high (for example, 60 ° C.), hot water without heating of the electric heater 58 can be taken out from the emergency water intake valve 44 (at this time, hot water at the same temperature can be taken out by opening the drain plug 42).

  FIG. 9 shows a water passage when the emergency water intake valve 44 is open. By operating the exhaust heat recovery pump 52, the water in the hot water storage tank 13 is taken out from the water intake 16 at the lower part of the hot water storage tank 13 even during a water outage, and the exhaust heat recovery heat exchanger 51 of the fuel cell 4 is removed. It flows out from the 3rd connection port 44c of the emergency intake valve 44 via. Originally, the water passing through the exhaust heat recovery heat exchanger 51 is heated by an electric heater 58 that is used to warm the cell stack and the like in the fuel cell 4 when the fuel cell 4 is started to assist the start.

  Since the water supply is not replenished when the water is shut off, if the water in the hot water storage tank 13 flows out from the third connection port 44c of the emergency water intake valve 44, the hot water storage tank 13 has a negative pressure. As a result, outside air is taken into the hot water storage tank 13 from the vacuum breaker 45.

  The temperature of the hot water coming out of the emergency intake valve 44 becomes a natural temperature. That is, if gas is supplied and the fuel cell 4 is operating, the hot water discharged from the emergency intake valve 44 is discharged from the electric heater 58 and the exhaust of the fuel cell 4 while passing through the exhaust heat recovery device 50. The temperature is raised by heat. At this time, the exhaust heat recovery pump 52 is operated at a maximum (for example, 1 liter per minute), the temperature of the water taken out from the emergency intake valve 44 is raised by, for example, about 15 degup by the exhaust heat of the fuel cell 4, and an electric heater 58, for example, a temperature increase of about 10 degup is performed (for example, when the water temperature is 15 ° C. extracted from the water intake 16, 45 ° C. = 15 ° C. + 15 deg up + 10 deg up).

  If it is determined that the temperature of the water taken out from the water intake 16 is high enough that the cooling becomes insufficient even when the maximum capacity of the exhaust heat recovery pump 52 is exceeded, the operation of the fuel cell 4 is stopped. In this way, including the stop of the fuel cell 4 due to the full storage of the hot water storage tank 13, for example, if the fuel cell 4 is not operating with the supply of fuel gas stopped, the hot water coming out from the emergency intake valve 44 is exhausted. The temperature is raised only by the heat from the electric heater 58 while passing through the recovery device 50 (for example, 55 ° C. = 45 ° C. + 0 deg up + 10 deg up when the water temperature taken out from the water intake 16 is 45 ° C.).

  Thereafter, the control unit 20 monitors whether or not the emergency intake valve 44 is closed by manual switching (step S103). When the emergency intake valve 44 is closed (step S103; Yes), the forced operation in step S102 is performed. Is instructed to stop the fuel cell 4 (step S104).

  In addition, when the selection switch of whether to heat by the electric heater 58 is provided near the emergency intake valve 44 and the user selects heating unnecessary, exhaust heat recovery is performed in the forced operation of step S102. The maximum operation of the pump 52 is instructed to the fuel cell 4, and the operation of the pump 57 may be instructed but the operation of the electric heater 58 may not be instructed (for example, the temperature of water taken in from the water intake 16 is 45). When the temperature is as low as ℃). When the fuel cell 4 is stopped (for example, when the temperature of the water taken in from the water intake 16 is as high as 45 ° C. or when the supply of fuel gas is stopped), the exhaust heat recovery pump 52 Only the maximum operation may be instructed, and the operation of the pump 57 and the electric heater 58 may not be instructed.

  In this way, even in the event of a water outage, the water in the hot water storage tank 13 can be used as hot water and provided to the user. Further, when the fuel cell 4 is in operation, the hot water coming out of the third connection port 44c of the emergency intake valve 44 recovers the exhaust heat of the fuel cell 4, so that the fuel cell 4 can be cooled to continue power generation. To contribute.

  If the fuel cell 4 continues to generate power even after the water is shut off, the hot water storage tank 13 will eventually become fully charged, and the entire hot water storage tank 13 will become hot water. When the battery is full, the first temperature sensor 18a below the hot water storage tank 13 detects a temperature higher than a predetermined temperature (for example, 45 ° C.), and the power generation of the fuel cell 4 is stopped. If the hot water storage tank 13 is full, the exhaust heat recovery pump 52 may be operated at the maximum and the electric heater 58 and the pump 57 may be operated in the forced operation of step S102. If the use of hot water from the emergency intake valve 44 is continued in this state, for example, 70 to 80 ° C. hot water is taken out from the intake port 16 in due course. In accordance with this, the electric heater 58 and the pump 57 may not be operated.

  Further, a hot water temperature control setting unit is provided near the emergency intake valve 44, and the exhaust heat recovery pump 52 and the electric power are set according to the set temperature and the temperature of the heat recovery pipe low temperature side temperature sensor 22b or the first temperature sensor 18a. The capacity of the heater 58 may be controlled. Further, although the exhaust heat recovery pump 52 has a capacity of only 1 liter per minute even in the maximum operation, a capacity having a slightly higher capacity may be used to vary the capacity according to the set temperature.

  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 configuration in which the fuel cell 4 does not include the exhaust heat recovery device 50 and is provided in the hot water storage tank unit 11, the controller 20 of the hot water storage tank unit 11 replaces an instruction to the fuel cell 4 in the emergency hot water discharge function. The exhaust heat recovery pump 52, the electric heater 58, and the pump 57 included in the apparatus are controlled to forcibly operate.

  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.

  In the embodiment, the preferred example in which the hot water supply control mode is the first mode, the second mode, and the third mode has been described. However, if there is at least the first and second modes, a configuration without the third mode may be used. .

  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 emergency hot water supply function, the electric heater 58 of the fuel cell 4 is used to raise the temperature of the hot water in the hot water storage tank 13 and discharge it. It is not limited to this. For example, an electric heater may be provided in the middle of the heat recovery pipe 53 upstream from the emergency water intake valve 44 and used.

  Further, in the embodiment, the example in which the fuel cell 4 is used as the power generation device has been described. However, any device that exhausts heat during power generation, such as an engine-type power generation device, may be used.

2 ... Bath (tub)
3. Heating radiator 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 21b ... Second connection port 21c ... Third connection port 22a ... Heat recovery piping high temperature side temperature Sensor 22b ... Heat recovery pipe low temperature side sensor 23 ... Mixer 23a ... First mixer 23b ... Second mixer 23c ... Third mixer 24 ... Overpressure relief valve 25 ... Intake valve 26 ... Tank outlet temperature sensor 28 ... Connecting pipe high temperature side 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 ... Quantity 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 port 38b ... Second connection port 38c ... Third connection port 39 ... Check valve 41 ... Drain pipe 42 ... Drain plug 44 ... Emergency intake valve 44a ... First connection port of emergency intake valve 44b ... Second connection port of emergency intake valve 44c ... Third of emergency intake valve Connection port 45 ... Vacuum breaker 50 ... Waste heat recovery device 51 ... Waste heat recovery heat exchanger 51a ... Secondary water pipe 52 ... Waste heat recovery pump 53 ... Heat recovery pipe 53a ... Heat recovery pipe (low temperature)
53b ... Heat recovery piping (high temperature)
54 ... Bypass pipe 56 ... Primary circulation circuit 57 ... Pump 58 ... Electric heater 61 ... Connection piping (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 (6)

A hot water storage system for recovering the temperature of water in a hot water storage tank for storing hot water to be used for tapping hot water by recovering exhaust heat of a predetermined power generation device,
A heat exchanger for recovering the exhaust heat;
A circulation line having a start end connected to a water intake at a lower portion of the hot water storage tank, via the heat exchanger, and an end connected to a return opening at an upper portion of the hot water storage tank;
A circulation pump for circulating the water in the hot water storage tank through the circulation line;
A drain port that is provided in the circulation line downstream from the heat exchanger and the circulation pump and is manually opened and closed;
A sensor for detecting the open / closed state of the drain;
When the sensor detects an open state of the drain, a control unit that operates the circulation pump;
A hot water storage system characterized by comprising: An electric heater for raising the temperature of the water passing through the circulation line;
The hot water storage system according to claim 1, wherein the control unit operates the electric heater when the sensor detects an open state of the drain port. This is a hot water storage system that recovers the temperature of water in a hot water storage tank for storing hot water to be used for tapping hot water by recovering the exhaust heat of a predetermined power generator equipped with a heat exchanger for exhaust heat recovery and a circulation pump. And
A circulation line having a start end connected to a water intake at a lower part of the hot water storage tank, via the heat exchanger and the circulation pump, and an end connected to a return port at an upper part of the hot water storage tank;
A drain port provided in the circulation line downstream of the heat exchanger and the circulation pump and manually opened and closed;
A sensor for detecting the open / closed state of the drain;
A control unit that instructs the fuel cell to operate the circulation pump when the sensor detects an open state of the drain;
A hot water storage system characterized by comprising: The predetermined power generation device further includes an electric heater that raises the temperature of water sent by the circulation pump,
The hot water storage system according to claim 3, wherein the control unit instructs the fuel cell to operate the electric heater when the sensor detects an open state of the drain port. . The hot water storage system according to any one of claims 1 to 4, further comprising an air intake portion that takes in air from an upper portion of the hot water storage tank when hot water flows out from the drain port. The hot water storage system according to any one of claims 1 to 5, wherein the predetermined power generation device is a fuel cell.

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