JP6050581B2 - Hot water storage system - Google Patents

Description

  The present invention relates to a hot water storage system that recovers heat from a heat source such as a fuel cell (a gas engine generator, a fuel processing device (reformer), etc.) to heat and supply hot water in a hot water storage tank. The present invention relates to a hot water storage system that supplies hot water by supplementing the shortage with a backup heat source machine when heat storage is insufficient.

  In the conventional hot water storage system, when the hot water temperature in the hot water storage tank is sufficiently high, the mixing valve mixes the hot water from the hot water storage tank with the hot water to discharge the hot water at the set temperature, and when the hot water temperature is insufficient, The hot water was heated to a set temperature with a back-up heat source machine at the latter stage, and the hot water was discharged (this was called a water supply preheating method).

  FIG. 11 shows a configuration example of a hot water storage system 100 of a feed water preheating method that recovers exhaust heat of a fuel cell. This system includes a hot water storage tank unit 101, a heat recovery device 110 that recovers exhaust heat from a heat source 130 such as a fuel cell, and a gas water heater 120 as a backup heat source unit. The heat recovery apparatus 110 includes an exhaust heat recovery heat exchanger 111 that recovers heat from a heat source and an exhaust heat recovery pump 112. When the exhaust heat recovery pump 112 is operated, the hot water in the hot water storage tank 102 is stored from the lower part of the hot water storage tank via the heat recovery pipe (low temperature) 114, the exhaust heat recovery heat exchanger 111, and the heat recovery pipe (high temperature) 115. It circulates through the path returning to the upper part of the tank 102 and is heated when passing through the exhaust heat recovery heat exchanger 111.

  A water supply pipe 104 is connected to the lower water supply port 103 of the hot water storage tank 102, and a hot water discharge pipe 106 is connected to the upper hot water outlet 105. A mixer 107 that mixes hot water from the hot water storage tank 102 and water from the water supply pipe 104 at a set mixing ratio is provided in the middle of the hot water discharge pipe 106, and the outlet side of the mixer 107 is connected piping. A pipe 121 is connected to the water supply connection port 122 of the backup heat source machine 120.

  In the above system, when hot water is supplied in a state where the hot water storage tank 102 has sufficiently stored heat, the hot water in the hot water storage tank 102 and the hot water are mixed by the mixer 107 to produce hot water at a set temperature and sent to the backup heat source machine 120 for backup. The heat source unit 120 supplies hot water as it is without performing additional heating. In addition, when there is no heat storage in the hot water storage tank 102, hot water or water having a temperature lower than the set temperature in the hot water storage tank 102 is sent to the backup heat source unit 120 and heated to the set temperature by the backup heat source unit 120 to supply hot water. If the hot water in the hot water storage tank 102 is slightly lower than the set temperature and is sent to the backup heat source unit 120 as it is, the hot water supply temperature exceeds the set temperature even if the backup heat source unit 120 is operated with the minimum capacity. For example, hot water whose temperature is intentionally lowered by mixing hot water with hot water is sent to the backup heat source device 120 and heated to a set temperature by the backup heat source device 120 to supply hot water.

JP 2010-236713 A

  In the hot water storage system, the pressure loss in the hot water storage tank and the pressure loss in the connection piping are added, compared with the case where the hot water is supplied directly from a gas water heater or the like, and the pressure loss of the entire system becomes large. In addition, depending on the construction conditions, the hot water storage tank unit and the backup heat source machine must be installed separately, and the connection pipe from the hot water storage tank unit to the backup heat source machine becomes longer, and the pressure loss further increases accordingly.

  In the case of the hot water storage system using the water supply preheating method described above, the entire amount of hot water to be supplied always passes through the connecting piping and the backup heat source unit, so it is strongly affected by pressure loss, and in particular, in the low water pressure area, the amount of hot water is reduced. End up.

  Therefore, the present applicant has devised a post-mixing type hot water storage system. FIG. 12 shows a schematic configuration of a post-mixing hot water storage system 150. The same parts as those in FIG. 11 are denoted by the same reference numerals. The hot water storage system 150 supplies hot water obtained by mixing hot water obtained by heating the water supply with the backup heat source unit 120 with hot water and water supply from the hot water storage tank 102 to a set mixing ratio by the mixer 151. When supplying hot water in a state where the hot water storage tank 102 has sufficiently stored heat, the hot water and hot water in the hot water storage tank 102 are mixed by the mixer 151 to supply hot water (to make the tank hot water), and the hot water storage tank 102 has no or insufficient heat storage. When water is supplied, hot water obtained by heating the water supply to a temperature sufficiently higher than the set temperature by the backup heat source unit 120 and the supplied water are mixed by the mixer 151 to produce hot water at the set temperature (hereinafter referred to as hot water supply hot water). In the hot water supply hot water, the amount of hot water passing through the backup heat source unit 120 is reduced by making hot water sufficiently higher than the set temperature by the backup heat source unit 120 to reduce pressure loss.

  In the above-described post-mixing type hot water storage system, when there is no heat storage in the hot water storage tank at the start of hot water supply, hot water supply hot water is used as described above, but if there is cold water in the pipe 152 from the backup heat source machine to the mixer, This cold water flows into the mixer 151. At this time, if the pipe 152 from the backup heat source unit 120 to the mixer 151 is long, the time from when the user opens the hot water tap until the hot water at the set temperature comes out becomes longer than in the case of the tank hot water. .

  In particular, when the demand for hot water supply is very large and the exhaust heat from fuel cells, etc. is much lower than the demand for hot water supply, the hot water supply from the hot water supply will increase, and the user will always wait for a long time before the hot water comes out. Become.

  The present invention is intended to solve the above problem, and an object thereof is to provide a post-mixing type hot water storage system capable of supplying hot water at a set temperature in a short time after opening the hot water tap at any time. .

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

[1] A hot water storage tank supplied with water from the lower water inlet and having a hot water outlet on the upper part,
A heating device that heats water in the hot water storage tank with heat recovered from a predetermined heat source;
A mixer that mixes hot water from a backup heat source that heats the water supply and hot water from the outlet of the hot water storage tank and the water supply at a set mixing ratio to supply hot water;
A transfer path leading from the lower part of the hot water storage tank to the upper part of the hot water storage tank via the backup heat source unit;
A circulation pump for transferring hot water from the lower part of the hot water storage tank to the upper part of the hot water storage tank through the transfer path;
When the temperature of the hot water going from the backup heat source unit to the upper part of the hot water storage tank is lower than a predetermined temperature, the route is changed so that the hot water going to the upper part of the hot water storage tank goes to the inlet of the backup heat source unit A route changing unit for switching to the circulation route,
A controller that controls heating in the backup heat source unit and a mixing ratio of the mixer so that hot water at a set temperature is supplied from the mixer;
Have
The controller is configured to operate the circulation pump and heat the backup heat source unit when the hot water having a predetermined temperature or higher does not exist in the upper part of the hot water storage tank, and draw out from the lower part of the hot water storage tank. The hot water is heated by the backup heat source device and transferred to the upper part of the hot water storage tank through the transfer path, and the hot water storage tank is controlled so that a certain amount of remaining hot water is always secured during standby for hot water supply ,
The path from the backup heat source unit to the upper part of the hot water storage tank in the transfer path branches from the first pipe from the hot water supply port of the backup heat source unit to the mixer and reaches the upper part of the hot water storage tank. Including the branch pipe and the first pipe from the hot water supply port to the branch point of the branch pipe,
The branch pipe is branched from a location from the mixer of the first pipe,
The circulation path includes at least the first pipe to the branch point,
The control unit, as a hot water supply control mode, mixes hot water and hot water from a hot water storage tank to supply hot water having a set temperature, and heated the hot water to a temperature higher than the set temperature by the backup heat source unit. At least a second mode of mixing hot water and water supply to supply hot water at a set temperature;
When switching to the second mode during the hot water supply operation in the first mode, the path change unit sets the circulation path, operates the circulation pump while heating by the backup heat source unit, and the backup heat source A hot water storage system , wherein after the hot water discharged from the machine is circulated through the circulation path for a predetermined time or more, the circulation pump is stopped and the hot water supply operation of the second mode is performed .

  In the above invention, when there is no predetermined amount or more of hot water above the predetermined temperature in the upper part of the hot water storage tank, the water extracted from the lower part of the hot water storage tank is heated by the backup heat source machine and transferred to the upper part of the hot water storage tank. Accordingly, a state where a predetermined amount or more of hot water is accumulated in the upper part of the hot water storage tank is maintained, and hot water supply from the hot water storage tank can be performed any time when a hot water supply request is received.

  In the above invention, while the temperature of the hot water going from the backup heat source machine to the upper part of the hot water storage tank is low, the hot water is recirculated and heated so as to go to the water inlet of the backup heat source machine. Transfer to the top of the tank. This prevents low-temperature hot water from flowing into the hot water storage tank at the beginning of the transfer operation.

In the above invention, when switching from the first mode in which hot water is supplied from the hot water storage tank to the second mode in which hot water is supplied from the backup heat source machine, the first pipe from the hot water supply port of the backup heat source machine to the mixer is cold. Since water may accumulate, this is circulated through the circulation path, the temperature is raised by the backup heat source machine, and the mode is switched to the second mode after the hot water temperature in the first pipe is increased. Thus, when the hot water in the hot water storage tank is insufficient during hot water supply in the first mode and the mode is switched to the second mode, the hot water supply temperature is prevented from decreasing for a long time during hot water supply.
[ 2 ] When the temperature detected by a temperature sensor provided in the vicinity of the branch location in the first pipe from the hot water supply port to the branch location is higher than a predetermined temperature, the control unit is configured to provide the circulation pump. The hot water storage system according to [ 1 ], wherein the hot water supply operation in the second mode is stopped.

  According to the hot water storage system according to the present invention, hot water having a set temperature can be supplied in a short time after the hot water tap is opened.

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 at the time of switching from a 1st mode to a 2nd mode. It is explanatory drawing which shows the flow of the hot water of the state in the middle of the transition which gradually increased the mixing ratio of the hot water from a bath water heater at the time of switching from a 1st mode to a 2nd mode. It is explanatory drawing which shows the flow (circulation during temperature rising) of the hot water in the hot water replenishment operation | movement to the hot water storage tank upper part. It is explanatory drawing which shows the flow (transfer to the tank upper part) of the hot water in the hot water replenishment operation | movement to the hot water storage tank upper part. It is a figure which shows schematic structure of the hot-water supply system of the conventional hot-water supply preheating system. It is a figure which shows the basic composition of the hot water storage system of an after mixing system.

  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 according to an embodiment 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 is connected by heat recovery pipes 53a and 53b so that an exhaust heat recovery circulation path for circulating the water of the hot water storage tank 13 is formed between them. Has been. Specifically, one end of a heat recovery pipe (low temperature) 53 a is connected to the water intake 16 of the hot water storage tank 13, and the other end of the heat recovery pipe (low temperature) 53 a is connected to the inlet side of the exhaust heat recovery heat exchanger 51. ing. The exhaust heat recovery pump 52 is inserted into a heat recovery pipe (low temperature) 53a in the vicinity of the entrance side of the exhaust heat recovery heat exchanger 51, and the exhaust heat recovery pump 52 uses the water in the heat recovery pipe (low temperature) 53a. Water is fed from the intake 16 side of the hot water storage tank 13 toward the entrance side of the exhaust heat recovery heat exchanger 51.

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

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

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

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

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

  The inlet side of the first mixer 23a is connected to a hot water outlet 15 of the hot water storage tank 13 by piping, and an overpressure relief valve 24, an intake valve 25, and a tank outlet temperature sensor 26 are provided in the middle of the piping. . The entrance side of the second mixer 23 b is connected to the hot water supply connection port of the bath water heater 70 by a connection pipe (high temperature) 61. A connecting pipe high temperature side temperature sensor 28 for detecting the temperature of hot water 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 in the vicinity of the outlet side 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 pipe 12b via 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 manually opening and closing the pipe line is provided in the middle of the drain pipe 41.

  Further, in the hot water storage tank unit 11, a branch pipe 43 branched from a location closer to the mixer 23 than the connection pipe high temperature side temperature sensor 28 of the connection pipe (high temperature) 61 is slightly recovered from the heat recovery pipe high temperature side temperature sensor 22a. It is connected to the heat recovery pipe (high temperature) 53b at the location on the heat exchanger 51 side and merges. In the middle of the branch pipe 43, a check valve 44 for preventing a back flow from the heat recovery pipe (high temperature) 53b side to the connection pipe (high temperature) 61 side is provided. The check valve 44 prevents the hot water in the hot water storage tank 13 from flowing out to the bath water heater 70 side. In the hot water storage tank unit 11, the second connection port of the second three-way valve 38 branches off from the heat recovery pipe (low temperature) 53 a at a position slightly on the exhaust heat recovery heat exchanger 51 side from the position where the bypass pipe 54 is joined. A joining pipe 45 joined to the pipe 12b is provided in the vicinity of the entrance side of 38b.

  A circulating pump 46 and a pump solenoid valve 47 for supplying water from the heat recovery pipe (low temperature) 53a to the pipe 12b are provided in the middle of the junction pipe 45. The pump solenoid valve 47 opens and closes the merge pipe 45. The pump solenoid valve 47 prevents water supply from the pipe 12 b from flowing back through the circulation pump 46 and flowing into the lower part of the hot water storage tank 13 from the water intake 16. The pump solenoid valve 47 is connected to the water supply connection port of the bath water heater 70 in the direction of the water supply connection port of the bath water heater 70 when the hot water is supplied in the second mode (hot water supply hot water supply mode) described later. It is prevented from flowing out through (low temperature) 62. In addition, the branch location of the branch pipe 43 is a location closer to the mixer 23 in the entire length of the connection pipe (high temperature) 61, and the pipe length from the branch location to the mixer 23 is from the branch location to the bath water heater 70. It is sufficiently shorter than the piping length to the hot water supply connection port.

  The hot water storage tank unit 11 is provided with an atmospheric temperature sensor 49 for measuring the atmospheric temperature (outside air temperature).

  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.

  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 with a function to retreat.

  As shown in FIG. 2, the bath water heater 70 includes a one-can two-water channel type heat exchanger 72 through which a first heat exchange water pipe 72 a and a second heat exchange water pipe 72 b pass, and a burner that heats the heat exchanger 72. 73 is provided. 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.

  In addition, a remote controller 92 is normally connected directly to the control unit 91 via a wiring. Here, however, the control is performed 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 unit 91 is connected to the control unit 20 through wiring, and a remote control (a common remote control for the hot water tank unit 11 side and the bath water heater 70) 92 is connected to the control unit 20 through wiring. The common remote control 92 includes switches for receiving various operations from the user such as designation of hot water supply set temperature and bath set temperature, start / end instructions for hot water filling and reheating, and power on / off, as well as operation state and set temperature. It is comprised with the display part etc. which display etc.

  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 common 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.

  In addition, the hot water supply system 10 of the present invention always keeps hot water at a predetermined temperature or higher in the upper part of the hot water storage tank 13 so that hot water at a hot water supply set temperature comes out in a short time after the user opens the hot water tap. It operates so as to maintain a state where a predetermined amount or more has been accumulated.

  Hot water supply in the bath hot water supply system 10 is performed in one of the following three control modes.

(1) First mode (tank hot water mode)
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 detected temperature of the hot water temperature sensor 18d provided in the hot water storage tank 13 is the hot water supply set temperature (actually, for example, + 1 ° C. from the hot water set temperature in consideration of a temperature drop in the hot water supply pipe) In the above 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.

[Calculation of effect]
When the hot water supply temperature is 15 ° C, the hot water supply set temperature is 40 ° C, and the hot water supply flow rate is 8L / min. ) 61 and connecting pipe (low temperature) 62, hot water flows at 8 L / min. On the other hand, when hot water of 55 ° C. is received from the bath water heater 70, the flow rate flowing through the connecting pipe (high temperature) 61 and the connecting pipe (low temperature) 62 may be 5 L / min. To make 8L / min of 40 ° C hot water. Since the pressure loss increases as the flow velocity (proportional to the flow rate when the pipe diameter is the same) is increased, reducing the flow rate greatly contributes to pressure loss reduction.

  In the case of the hot water preheating method shown in FIG. 11, even if there is heat storage in the hot water storage tank, hot water storage tank unit makes hot water of 40 ° C and 8L / min and transfers the entire amount to the water supply port of the hot water heater as a backup heat source machine. Will flow through the pipes and water heaters. Even when there is no heat storage in the hot water storage tank, 8 L / min of water is sent from the hot water storage tank unit to the hot water heater and heated to 40 ° C. In any case, it is necessary to flow 8 L / min through the pipe to the water heater and the water heater.

  According to the experimental results using a cross-linked polyethylene pipe having an inner diameter of 16 mm, when the pipe length is 25 m (when the pipe reciprocates to 25 m, it corresponds to a case where the bath water heater 70 and the hot water storage tank unit 11 are installed 12.5 m apart). As a result, the pressure loss of the pipe connected to the bath water heater 70 is 8 L / min and the pipe pressure loss is 11 kPa, and 5 L / min is 5 kPa. The pressure loss is reduced by 55%.

(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.

  As described above, the bath hot water supply system 10 operates so as to maintain a state in which a predetermined amount or more of hot water at a predetermined temperature or more is accumulated in the upper part of the hot water storage tank 13, and in most cases, the first mode (tank hot water mode) ) Hot water supply starts. When the hot water supply set temperature is set higher than the hot water temperature in the upper part of the hot water storage tank 13, the hot water is started in the third mode.

  After the hot water supply is started in the first mode (tank hot water mode), when the hot water supply continues for a long time and the hot water supply in the first mode cannot be continued, the hot water supply in the third mode is started from the remaining hot water temperature in the hot water storage tank 13. Switch to the third mode if possible. If this is not possible, hot water is supplied by switching to the second mode.

  When switching from the first mode to the second mode, if there is cold water in the connecting pipe (high temperature) 61 from the bath water heater 70 to the mixer 23 before switching, this cold water flows into the second mixer 23b. Therefore, the hot water of the hot water supply set temperature cannot be supplied. After a while, the hot water heated by the bath water heater 70 reaches the second mixer 23b and hot water supply at the set hot water temperature is possible. The water supply becomes uncomfortable for the user. In particular, when the pipe 61 from the bath water heater 70 to the mixer 23 of the hot water storage tank unit 11 is long, the time to become water during hot water supply becomes long. Therefore, when switching from the first mode to the second mode, the following special control is performed. In addition, when switching from the first mode to the third mode during hot water supply, the hot water remaining in the hot water storage tank 13 can be mixed and hot water can be mixed, so that a temperature drop hardly occurs.

<Switching operation from the first mode to the second mode>
After the hot water supply is started in the first mode (tank hot water), when the heat storage (hot water amount) in the hot water storage tank 13 is insufficient and the hot water control mode is switched to the second mode (hot water supply hot water), the second mode is set. Before switching, the following control is performed.

  Note that the position at which the hot water temperature sensor 18d is attached is determined from the amount of retained water in the connection pipe (high temperature) 61, the maximum hot water flow rate, and the like. That is, the amount of water in the hot water storage tank 13 above the position where the hot water temperature sensor 18d is attached is equal to or greater than the maximum amount of hot water from the hot water storage tank 13 used while switching from the first mode to the second mode. The attachment position of the hot water temperature sensor 18d is set.

  First, it is determined that there is sufficient heat storage in the hot water storage tank 13 and the hot water supply is started in the first mode (tank hot water). Then, the hot water storage (hot water that can be discharged at the set temperature) will soon occur from the temperature detected by the hot water temperature sensor 18d. When it is determined that the circulation pump 46 will disappear, the circulation pump 46 is operated.

  Thereby, the connection pipe (high temperature) 61, the branch pipe 43, the heat recovery pipe (high temperature) 53b from the bath water heater 70 to the branching point of the branch pipe 43, the first three-way valve 21 in the B direction, the bypass pipe 54, the heat Hot water circulates in a path (referred to as a bypass circulation path) that returns to the bath water heater 70 via the recovery pipe (low temperature) 53a, the junction pipe 45, the pipe 12b, the second three-way valve 38 in the C direction, and the connection pipe (low temperature) 62 To do. FIG. 7 shows the flow of hot water when the circulation pump 46 is operated. In the figure, the thick line portion indicates the detour circulation path, and the thick broken line indicates the discharge path by tank discharge.

  When hot water flows through the detour circulation path by the operation of the circulation pump 46 and water flows through the bath water heater 70, the bath water heater 70 that detects this by the flow sensor 85 starts combustion heating. The bath water heater 70 discharges hot water at a temperature instructed by the control unit 20 of the hot water storage tank unit 11. As a result, the inside of the connection pipe (high temperature) 61 is gradually warmed by the hot water from the bath water heater 70. The circulation state in which the circulation pump 46 is operated is continued until the temperature detected by the connecting pipe high temperature side temperature sensor 28 increases to a predetermined temperature. Here, when the detected temperature of the connecting pipe high temperature side temperature sensor 28 becomes higher than the detected temperature of the tank upper temperature sensor 18e of the hot water storage tank 13, the circulation pump 46 is stopped and switched to the second mode (hot water supply hot water).

  Specifically, when the detected temperature of the connecting pipe high temperature side temperature sensor 28 becomes higher than the detected temperature of the tank upper temperature sensor 18e of the hot water storage tank 13, the mixer 23 is controlled to maintain the hot water supply set temperature while maintaining the first temperature. The second mixer 23b is gradually opened while the mixer 23a is gradually closed, so that the mixing ratio of hot water from the bath water heater 70 gradually increases.

  FIG. 8 shows the flow of hot water at this time. If the water to be squeezed in the connection pipe (high temperature) 61 on the side of the second mixer 23b from the branching point of the branch pipe 43 is stopped, the water to be squeezed in that part is gradually opened by opening the second mixer 23b. Will flow into the second mixer 23b (the path indicated by the thick dashed line in FIG. 8), but initially the hot water at the hot water supply set temperature is maintained by slightly opening the second mixer 23b. The first mixer 23a is fully closed when the water to be filled is used up and the inside of the connection pipe (high temperature) 61 becomes hot water heated by the bath water heater 70. When the second mixer 23b is opened, the flow rate of the bath water heater 70 increases by an amount corresponding to the circulation flow rate of the circulation pump 46, but the increased amount is the second three-way valve 38 in the C direction from the water supply pipe 12. The feed water is supplied through the connecting pipe (low temperature) 62.

  When the mixing ratio of hot water from the hot water storage tank 13 becomes zero (the first mixer 23a is fully closed), that is, when the transition to the second mode is completed, the circulation pump 46 is stopped to end the circulation state. The state after shifting to the second mode is as shown in FIG. When the flow rate of the second mixer 23b exceeds the minimum flow rate at which the bath water heater 70 can continue combustion, the circulation pump 46 may be stopped to end the circulation state.

  Further, instead of the condition that the detected temperature of the connecting pipe high temperature side temperature sensor 28 is higher than the detected temperature of the tank upper temperature sensor 18e of the hot water storage tank 13, the hot water heated by the bath water heater 70 is connected to the connecting pipe high temperature side temperature sensor. It is good also as a condition that it was confirmed that 28 places were reached. Specifically, in consideration of the temperature drop in the connecting pipe (high temperature) 61, the temperature detected by the connecting pipe high temperature side temperature sensor 28 is the temperature of the hot water set in the bath water heater 70 by the control unit 20 of the hot water storage tank unit 11. When the temperature reaches −3 ° C., the control may be such that the mixing ratio of the mixer 23 is changed and the transition to the second mode is started.

  Since the above transition control is performed, even when the water in the connection pipe (high temperature) 61 is cold when switching from the first mode (tank hot water) to the second mode (hot water heater hot water), the hot water supply set temperature The hot water supply for the street can be continued and the user is not uncomfortable.

<Replenishment operation of hot water to the tank top>
The hot water replenishment operation to the upper portion of the tank is an operation for maintaining a state where a predetermined amount or more of hot water at a predetermined temperature or more is accumulated in the upper portion of the hot water storage tank 13. In the hot water replenishment operation to the upper part of the tank, the water extracted from the lower part of the hot water storage tank 13 is heated to a predetermined temperature (for example, 55 ° C.) or higher by the bath water heater 70 and transferred to the upper part of the hot water storage tank 13. Hot water is replenished to the upper part of the hot water storage tank 13.

  Specifically, when the hot water temperature sensor 18d detects a predetermined temperature (for example, 45 ° C.) or less, the control unit 20 sets the second three-way valve 38 in the C direction and the second mixer 23b fully closed, The electromagnetic valve 47 is opened and the circulation pump 46 is operated. Further, a predetermined high temperature (for example, 60 ° C.) is set as the hot water supply set temperature for the bath water heater 70. The first three-way valve 21 is switched by the control unit 20 in the A direction at a certain temperature (for example, 45 ° C.) or higher and in the B direction at a temperature lower than the certain temperature (for example, 45 ° C.).

  When the hot water temperature heated by the bath water heater 70 and returned to the hot water storage tank unit 11 is less than a certain temperature (45 ° C.), the first three-way valve 21 is in the B direction, and therefore, the path shown by the thick line in FIG. Thus, hot water circulates bypassing the hot water storage tank 13. Specifically, the connecting pipe (high temperature) 61, the branch pipe 43, the heat recovery pipe (high temperature) 53b from the bath water heater 70 to the branch point of the branch pipe 43, the first three-way valve 21 in the B direction, the bypass pipe 54, Hot water circulates in a detour circulation path that returns to the bath water heater 70 via the heat recovery pipe (low temperature) 53a, the junction pipe 45, the pipe 12b, the second three-way valve 38 in the C direction, the connection pipe (low temperature) 62, and the bath. Heated when passing through the water heater 70.

  During the circulation, when the temperature of the circulating hot water is increased and the first three-way valve 21 is switched in the A direction, the hot water flows along a path indicated by a thick line in FIG. Specifically, the hot water in the lower part of the hot water storage tank 13 comes out from the intake port 16 and reaches the branching point of the merging pipe 45 to the heat recovery pipe (low temperature) 53a, the merging pipe 45, the pipe 12b, and the second three-way valve in the C direction. 38, connecting pipe (low temperature) 62, bath water heater 70, connecting pipe (high temperature) 61 to the branching point of the branch pipe 43, branch pipe 43, heat recovery pipe (high temperature) 53b, the first three-way valve 21 in the A direction Then, it flows so as to flow in from the return port 17 at the upper part of the hot water storage tank 13, heated while passing through the bath water heater 70, and transferred to the upper part of the hot water storage tank 13.

  In this way, hot water at a constant temperature (for example, 60 ° C. (depending on the set temperature for hot water supply to the bath water heater 70)) is accumulated in the upper part of the hot water storage tank 13, and the hot water temperature sensor 18d exceeds a certain temperature (for example, 55 ° C.). If detected, the circulation pump 46 is stopped, and the hot water replenishment operation to the upper part of the tank is finished.

  Since hot water is replenished to the upper part of the tank, hot water at a certain temperature (for example, 45 ° C.) or more is always accumulated in the upper part of the hot water storage tank 13 (above the installation position of the hot water temperature sensor 18d). In most cases, the hot water is discharged in the first mode (tank hot water mode) using hot water in the hot water storage tank 13, and the hot water is supplied in the hot water supply mode (second or third mode) using hot water from the bath water heater 70. Compared to the case where the hot water supply is started, the waiting time until the hot water of the hot water supply set temperature comes out can be shortened.

  For example, assuming that the bath water heater 70 heats to 60 ° C., hot water from the bath water heater 70 (5 L / min) and 20 ° C. water (5 L / min) are mixed to obtain 40 ° C., 10 L / min. Consider the case of hot water supply. If the connecting pipe (high temperature) 61 has an inner diameter of 13 mm and a length of 15 m, it takes about 40 seconds for the hot water heated by the bath water heater 70 to reach the hot water storage tank unit 11 15 m ahead. Therefore, by applying the present invention in which hot water of a certain temperature or more is always secured in the upper part of the hot water storage tank 13, the hot water waiting time is reduced by about 40 seconds compared with starting with hot water using hot water from the bath water heater 70. can do.

  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.

  In the embodiment, the heat recovery pipes 53a and 53b for exhaust heat recovery are partly used as a part of the path for transferring hot water in the hot water replenishment operation to the upper part of the tank, but may be an independent path. For example, the branch pipe 43 branched from the connection pipe (high temperature) 61 may be connected to the upper part of the hot water storage tank 13, and the lower part of the hot water storage tank 13 and the connection pipe (low temperature) 62 may be connected by the junction pipe 45. In this case, when the temperature of the hot water from the connecting pipe (high temperature) 61 is low, a three-way valve for bypassing the hot water storage tank 13 and connecting the branch pipe 43 to the merging pipe 45 (the temperature as in the first three-way valve 21). For switching the connection direction).

  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 heat source unit 4 may or may not be included. The exhaust heat recovery device 50 may be included in the heat source unit 4, and the bath water heater 70 may use an existing one.

  Although a preferred example having the first mode, the second mode, and the third mode as the hot water supply control mode has been shown, a configuration without the third mode may be used as long as there is at least the first and second modes.

  In the second mode, how much hot water is produced by the bath water heater 70 from the set temperature of the hot water supply may be determined as appropriate. However, the connection pipe 61 (high temperature), the connection pipe 62 (low temperature), and the bath water heater 70 are used. In order to reduce the pressure loss by reducing the amount of water flowing through the water, it is desirable that the temperature be sufficiently high as long as it is mixed with the feed water to obtain hot water at the hot water set temperature. When the backup heat source device is an instrument that requires water flow exceeding a predetermined minimum operating flow rate to perform a heating operation, such as a gas-fired bath water heater 70, the backup heat source device If the temperature of the hot water to be obtained is raised too much, the amount of hot water may fall below the minimum operating flow rate of the backup heat source machine. For this reason, in the second mode, it is desirable to control the temperature of hot water produced by the backup heat source device in a range where the amount of hot water supplied from the backup heat source device does not fall below the minimum operating flow rate of the backup heat source device.

  In addition, in the bath water heater 70 of the embodiment, the configuration including the incoming water temperature sensor 86 that detects the incoming water temperature is shown, but the incoming water temperature may be estimated by calculation without providing the incoming water temperature sensor 86. That is, an estimated value of the incoming water temperature Ti is calculated from Ti = To− (ηQ / W) from the hot water temperature To, the flow rate W, the gas amount (heating amount) Q measured at the last time when the hot water temperature was stabilized, and the efficiency η at this time. ), Etc. may be obtained by back calculation. In addition, efficiency (eta) measures and memorize | stores beforehand the value (efficiency (eta)) in each condition by changing tapping temperature and flow volume variously. Then, at the time of calculation, it is only necessary to obtain and use the efficiency η corresponding to the hot water temperature and the flow rate to be substituted for the calculation with reference to this memory.

  In the embodiment, the exhaust heat of the fuel cell is recovered and the water in the hot water storage tank 13 is heated. However, the heat source is not limited to the fuel cell. For example, a gas engine generator, a fuel processing device (reformer), etc. But you can.

  In the embodiment, the bath water heater 70 is a single-can two-water channel type, but it may be a water heater of a type in which the reheating of the bath and the hot water supply are performed by separate heat exchangers.

2 ... Bath (tub)
DESCRIPTION OF SYMBOLS 4 ... Heat source machine 10 ... Bath hot water supply system 11 ... Hot water storage tank unit 12 ... Water supply pipe 12b ... Piping 13 ... Hot water storage tank 14 ... Water supply port 15 ... Hot water outlet 16 ... Water intake port 17 ... Return port 18a ... First temperature sensor 18b ... First 2 temperature sensor 18c ... 3rd temperature sensor 18d ... Hot water temperature sensor 18e ... Tank upper temperature sensor 20 ... Control part 21 ... 1st three-way valve 21a ... 1st connection port 21b ... 2nd connection port 21c ... 3rd connection port 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 ... Overpressure 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 ... tapping temperature sensor 33 ... high Cut temperature sensor 34 ... Flow rate sensor 35 ... Feed water temperature sensor 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 43 ... Branch pipe 44 ... Check valve 45 ... Junction pipe 46 ... Circulating pump 47 ... Pump solenoid valve 49 ... Ambient temperature sensor 50 ... Waste heat recovery device 51 ... Exhaust Heat recovery heat exchanger 52 ... exhaust heat recovery pump 53 ... heat recovery pipe 53a ... heat recovery pipe (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 83 ... Bypass pipe 84 ... Bypass adjustment valve 85 ... Flow sensor 86 ... Incoming water temperature sensor 87 ... Bath circulation pump 88 ... Flowing water switch 89a ... Bath water temperature sensor 89b ... Bath Return temperature sensor 91 ... Control unit 92 ... Common remote control

Claims (2)

A hot water storage tank that is supplied with water from the lower water inlet and has a hot water outlet at the top,
A heating device that heats water in the hot water storage tank with heat recovered from a predetermined heat source;
A mixer that mixes hot water from a backup heat source that heats the water supply and hot water from the outlet of the hot water storage tank and the water supply at a set mixing ratio to supply hot water;
A transfer path leading from the lower part of the hot water storage tank to the upper part of the hot water storage tank via the backup heat source unit;
A circulation pump for transferring hot water from the lower part of the hot water storage tank to the upper part of the hot water storage tank through the transfer path;
When the temperature of the hot water going from the backup heat source unit to the upper part of the hot water storage tank is lower than a predetermined temperature, the route is changed so that the hot water going to the upper part of the hot water storage tank goes to the inlet of the backup heat source unit A route changing unit for switching to the circulation route,
A controller that controls heating in the backup heat source unit and a mixing ratio of the mixer so that hot water at a set temperature is supplied from the mixer;
Have
The controller is configured to operate the circulation pump and heat the backup heat source unit when the hot water having a predetermined temperature or higher does not exist in the upper part of the hot water storage tank, and draw out from the lower part of the hot water storage tank. The hot water is heated by the backup heat source device and transferred to the upper part of the hot water storage tank through the transfer path, and the hot water storage tank is controlled so that a certain amount of remaining hot water is always secured during standby for hot water supply ,
The path from the backup heat source unit to the upper part of the hot water storage tank in the transfer path branches from the first pipe from the hot water supply port of the backup heat source unit to the mixer and reaches the upper part of the hot water storage tank. Including the branch pipe and the first pipe from the hot water supply port to the branch point of the branch pipe,
The branch pipe is branched from a location from the mixer of the first pipe,
The circulation path includes at least the first pipe to the branch point,
The control unit, as a hot water supply control mode, mixes hot water and hot water from a hot water storage tank to supply hot water having a set temperature, and heated the hot water to a temperature higher than the set temperature by the backup heat source unit. At least a second mode of mixing hot water and water supply to supply hot water at a set temperature;
When switching to the second mode during the hot water supply operation in the first mode, the path change unit sets the circulation path, operates the circulation pump while heating by the backup heat source unit, and the backup heat source A hot water storage system , wherein after the hot water discharged from the machine is circulated through the circulation path for a predetermined time or more, the circulation pump is stopped and the hot water supply operation of the second mode is performed . The control unit stops the circulation pump when a temperature detected by a temperature sensor provided in the vicinity of the branch location in the first pipe from the hot water supply port to the branch location becomes higher than a predetermined temperature. The hot water storage system according to claim 1 , wherein the hot water supply operation is performed in the second mode.

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