JP2021148351A - Storage water heater - Google Patents

Abstract

To provide a storage water heater allowing for easily using water in a hot water storage tank during suspension of water supply.SOLUTION: A storage water heater 35 includes: heating means for heating water; a hot water storage tank 8 storing hot water heated by the heating means; a hot water supply mixing valve 22 causing a hot water obtained by mixing hot water caused to flow in from a hot water side inlet and water caused to flow in from a water side inlet to flow into hot water supply piping 24; and a water circuit in which hot water flows. The water circuit includes: outgoing piping serving as a water passage from the hot water storage tank 8 toward the heating means; return piping serving as a water passage from the heating means toward the hot water storage tank 8; a circulation pump 12 causing water in the outgoing piping and the return piping to flow; and a flow passage changeover valve 51. The changeover state of the flow passage changeover valve 51 includes a first changeover state where the return piping is communicated with the hot water storage tank 8; and a second changeover state where the return piping is not communicated with the hot water storage tank 8 but is communicated with the hot water side inlet or the water side inlet.SELECTED DRAWING: Figure 4

Description

The present disclosure relates to a hot water storage type water heater.

Patent Document 1 below discloses a hot water storage type water heater in which an emergency water intake faucet for taking out hot water stored in a hot water storage tank is attached to the outside of the outer case of the tank unit when water is cut off due to a disaster or the like. Has been done.

Japanese Unexamined Patent Publication No. 2010-190546

According to the technique disclosed in Patent Document 1, in an emergency when water outage occurs, in order for the user to take out hot water from the emergency water heater attached to the tank unit, the mounting position of the emergency water heater is always set. It is necessary to keep track of it on a daily basis and to carry out the work procedure for taking out hot water from the emergency water heater while referring to the instruction manual of the water heater. However, since the emergency water intake faucet is not usually used, the user often does not know where it is. In addition, the user may forget where the instruction manual of the water heater is stored, and the user may not be able to find out how to use the emergency water tap in an emergency. Therefore, there is a problem that it is difficult for the user to easily use the hot water in the hot water storage tank in an emergency.

The present disclosure has been made to solve the above-mentioned problems, and an object of the present disclosure is to provide a hot water storage type water heater that can easily use the water in the hot water storage tank when the water is cut off.

The hot water storage type water heater according to the present disclosure includes a heating means for heating water, a hot water storage tank for storing hot water heated by the heating means, hot water flowing in from the hot water side inlet, and water flowing in from the water side inlet. It is a hot water storage type water heater equipped with a mixing valve that allows mixed hot water to flow into the hot water supply pipe and a water circuit through which hot water flows. It is equipped with a return pipe that serves as a water channel from the hot water storage tank to the hot water storage tank, a circulation pump that allows water to flow from the outbound pipe and the return pipe, and a flow path switching valve. It includes a first switching state in which the return pipe is communicated with the hot water storage tank and a second switching state in which the return pipe is communicated with the hot water side inlet or the water side inlet without communicating with the hot water storage tank.

According to the present disclosure, it is possible to provide a hot water storage type water heater that can easily use the water in the hot water storage tank when the water is cut off.

It is a figure which shows the hot water storage type water heater according to Embodiment 1. FIG. It is a figure which shows the flow of hot water at the time of the hot water storage operation of the hot water storage type water heater shown in FIG. It is a figure which shows the flow of the hot water water at the time of the hot water supply operation in the normal water supply state of the hot water storage type water heater shown in FIG. It is a figure which shows the flow of hot water from a hot water storage tank to a faucet in a state of water outage of the hot water storage type water heater shown in FIG. It is a figure which shows the hot water storage type water heater by Embodiment 2. It is a figure which shows the flow of hot water from a hot water storage tank to a faucet in a state of water outage of the hot water storage type water heater shown in FIG.

Hereinafter, embodiments will be described with reference to the drawings. The same reference numerals are given to common or corresponding elements in each figure to simplify or omit the description. In the following description, the description of "water" means, in principle, liquid water, and may include low-temperature water to high-temperature hot water.

Embodiment 1.
FIG. 1 is a diagram showing a hot water storage type water heater 35 according to the first embodiment. The hot water storage type water heater 35 includes a water circuit through which hot water flows. The hot water storage type water heater 35 of the first embodiment includes a tank unit 33 and an HP unit 7. The HP unit 7 and the tank unit 33 are connected to each other via an HP going pipe 14, an HP returning pipe 15, and an electric wiring (not shown). The tank unit 33 has a built-in control unit 36. The operation of various valves, pumps, etc. included in the tank unit 33 and the HP unit 7 is controlled by a control unit 36 electrically connected to these. The control unit 36 includes, for example, a microcomputer having at least one memory and at least one processor. The control unit 36 corresponds to a control means for controlling the operation of the hot water storage type water heater 35. The control unit 36 has a timer function for managing the date and time. It should be noted that the configuration is not limited to the configuration in which the operation is controlled by a single control unit 36 as shown in the drawing, and the operation may be controlled by the cooperation of a plurality of control devices.

The remote controller 44 has a function of receiving an operation of the user regarding an operation operation command and a change of a set value. The remote controller 44 is an example of a user interface. The control unit 36 and the remote controller 44 are connected by wire or wireless so that data communication is possible in both directions. Although not shown, the remote controller 44 is equipped with a display unit that displays information such as the status of the hot water storage type water heater 35, an operation unit such as a switch operated by the user, a speaker, a microphone, and the like. The display unit of the remote controller 44 has a function as a notification means for notifying the user of information. The remote controller 44 in the present embodiment includes a display unit as a notification means, but as a modification, other notification means such as a voice guidance device may be provided.

In the present embodiment, the remote controller 44 may be installed on a wall such as a kitchen, a living room, or a bathroom. A plurality of remote controllers 44 may be able to communicate with the control unit 36. It may be configured so that other user interfaces, such as smartphones or smart speakers, can be used in place of or in addition to the remote control 44. The user interface and the control unit 36 may communicate with each other via a home network or the Internet.

The HP unit 7 is an example of a heating means for heating water. The HP unit 7 includes a refrigerant circuit in which a compressor 1, a water refrigerant heat exchanger 3, an expansion valve 4, and an air heat exchanger 6 are cyclically connected by a refrigerant pipe 5. The HP unit 7 operates the heat pump cycle by this refrigerant circuit. In the water refrigerant heat exchanger 3, water is heated by exchanging heat between the refrigerant compressed by the compressor 1 and the water guided from the tank unit 33.

The heating means in the present disclosure is not limited to a heat pump such as the HP unit 7. The heating means in the present disclosure may be, for example, a gas engine or one that heats water by utilizing geothermal heat.

The tank unit 33 contains the following various parts and pipes. The hot water storage tank 8 stores hot water. Inside the hot water storage tank 8, a temperature stratification can be formed in which the upper side is high temperature and the lower side is low temperature due to the difference in water density depending on the temperature.

The hot water storage tank 8 includes an upper part, an intermediate part, and a lower part. The middle portion of the hot water storage tank 8 is a height portion between the upper portion of the hot water storage tank 8 and the lower portion of the hot water storage tank 8. The hot water storage tank 8 is not limited to a single tank as shown in the figure, and may include a plurality of tanks connected in series. In the present disclosure, regarding the description of the position of the hot water storage tank 8 in the height direction, that is, in the vertical direction, when the hot water storage tank 8 includes a plurality of tanks connected in series, the highest tank to the lowest tank 8 are provided. The vertical position shall be specified in the entire hierarchy up to the tank.

At the lower part of the hot water storage tank 8, a tank lower port 8a, a water outlet 8b, and a water introduction port 8c are provided. A hot water introduction outlet 8d is provided above the hot water storage tank 8. In the illustrated example, the water inlet 8c is located higher than the tank lower port 8a and the water outlet 8b.

A third water supply pipe 9c is connected to the tank lower port 8a. The water supplied from a water source such as a water source through the first water supply pipe 9a is decompressed to a predetermined pressure by the pressure reducing valve 31, and then flows into the hot water storage tank 8 through the third water supply pipe 9c. On the surface of the hot water storage tank 8, a plurality of hot water storage temperature sensors 42 and 43 are attached at positions at different heights from each other. The control unit 36 can detect the amount of remaining hot water and the amount of heat stored in the hot water storage tank 8 by detecting the temperature distribution of the hot water in the hot water storage tank 8 with these hot water storage temperature sensors 42 and 43. Not limited to the illustrated example, three or more hot water storage temperature sensors may be provided in the hot water storage tank 8.

The tank unit 33 contains a bath heat exchanger 60 and a bath circulation pump 29. The bath heat exchanger 60 has a primary side flow path 60a and a secondary side flow path 60b. The bath heat exchanger 60 corresponds to a heat exchanger that exchanges heat between the primary fluid flowing through the primary side flow path 60a and the secondary fluid flowing through the secondary side flow path 60b. In the present embodiment, an example in which bath water circulating from the bath tub 30 flows through the secondary side flow path 60b as a secondary fluid will be described. Instead of this example, the secondary fluid in the present disclosure may be a fluid other than bath water. For example, the secondary fluid may be a heat medium for heating or water supplied from a water source.

The bath going pipe 27 connects the outlet of the secondary side flow path 60b and the bathtub 30. A bath going temperature sensor 37 for detecting the temperature of the bath water flowing out from the bath heat exchanger 60 is installed in the middle of the bath going pipe 27. The bath return pipe 28 connects the inlet of the secondary side flow path 60b and the bathtub 30. In the middle of the bath return pipe 28, a bath circulation pump 29 for circulating bath water in the secondary side flow path 60b and a bath return temperature sensor 38 for detecting the temperature of the bath water discharged from the bathtub 30 are provided. It is provided.

The tank unit 33 further includes a three-way valve 11, a circulation pump 12, a four-way valve 18, a hot water supply mixing valve 22, a bath mixing valve 23, and a flow path switching valve 51. Each of the three-way valve 11, the four-way valve 18, and the flow path switching valve 51 corresponds to a flow path switching means capable of switching the flow path of hot water.

The three-way valve 11 has an a port and a b port as an inlet and a c port as an outlet. The three-way valve 11 is configured so that the flow path can be switched between the two paths ac and bc. The four-way valve 18 has an inlet b port and a c port, and an outlet a port and a d port. The four-way valve 18 is configured so that the flow path can be switched between the four paths of ab, ac, bd, and cd. The flow path switching valve 51 has an a port, a b port, and a c port.

The low temperature pipe 10 connects the water outlet 8b and the a port of the three-way valve 11. The HP going pipe 14 connects the c port of the three-way valve 11 and the water inlet of the water refrigerant heat exchanger 3. A circulation pump 12 is connected in the middle of the HP going pipe 14. The HP return pipe 15 connects the hot water outlet of the water refrigerant heat exchanger 3 and the c port of the four-way valve 18. The first bypass pipe 16 connects the a port of the four-way valve 18 and the water introduction port 8c. The second bypass pipe 17 connects the branch portion 54 provided in the HP going pipe 14 between the circulation pump 12 and the water refrigerant heat exchanger 3 and the b port of the four-way valve 18. The hot water supply pipe 13 connects the d port of the four-way valve 18 and the a port of the flow path switching valve 51. The pipe 20a connects the upper part of the hot water storage tank 8 and the inlet of the primary side flow path 60a. The pipe 20b connects the outlet of the primary side flow path 60a and the b port of the three-way valve 11.

Each of the hot water supply mixing valve 22 and the bath mixing valve 23 has a hot water side inlet and a water side inlet, and adjusts the hot water supply temperature by mixing the hot water flowing in from the hot water side inlet and the water flowing in from the water side inlet. do. One end of the first water supply pipe 9a is connected to a water source such as water services. The second water supply pipe 9b and the third water supply pipe 9c are connected to the other end of the first water supply pipe 9a via the pressure reducing valve 31. The second water supply pipe 9b is connected to each water side inlet of the hot water supply mixing valve 22 and the bath mixing valve 23. One end of the tank upper pipe 21 is connected to the hot water introduction outlet 8d. The other end of the tank upper pipe 21 is connected to the b port of the flow path switching valve 51. One end of the hot water side pipe 50 communicates with each hot water side inlet of the hot water supply mixing valve 22 and the bath mixing valve 23. The other end of the hot water side pipe 50 is connected to the c port of the flow path switching valve 51.

The hot water supply mixing valve 22 is a flow rate of high-temperature water supplied from the hot water storage tank 8 through the tank upper pipe 21, the flow path switching valve 51, and the hot water side pipe 50, and low-temperature water supplied from the second water supply pipe 9b. By adjusting the ratio, hot water having a set temperature set by the user with the remote controller 44 is generated and flows into the hot water supply pipe 24. The downstream end of the hot water supply pipe 24 is connected to the hot water supply plug 34. For example, a faucet 90 such as a shower or a curan provided in a house and a hot water tap 34 are connected by an external hot water supply pipe 91 arranged outside the hot water storage type water heater 35. When the faucet 90 is opened, the hot water that has flowed into the hot water supply pipe 24 from the hot water supply mixing valve 22 is supplied to the faucet 90 through the hot water supply plug 34 and the external hot water supply pipe 91. The flow rate of water flowing through the hot water supply pipe 24 is hereinafter referred to as "hot water supply flow rate". A hot water supply flow rate sensor 52 that detects the hot water supply flow rate is installed in the hot water supply pipe 24.

The bath mixing valve 23 is a flow rate of high-temperature water supplied from the hot water storage tank 8 through the tank upper pipe 21, the flow path switching valve 51, and the hot water side pipe 50, and low-temperature water supplied from the second water supply pipe 9b. By adjusting the ratio, hot water having a set temperature set by the user with the remote controller 44 is generated and flows into the bath pipe 25. The hot water that has flowed into the bath pipe 25 from the bath mixing valve 23 flows into the bathtub 30 via the bath flow sensor 45, the bath solenoid valve 26, the bath going pipe 27, and the bath returning pipe 28.

A pressure relief valve 55 and a negative pressure operating valve 56 are connected in the middle of the tank upper pipe 21. When the pressure in the hot water storage tank 8 rises during the hot water storage operation, the pressure relief valve 55 opens and the hot water is discharged to the outside of the system, so that the pressure rise in the hot water storage tank 8 is suppressed. The negative pressure actuating valve 56 opens when the inside of the hot water storage tank 8 becomes negative pressure, so that external air flows into the hot water storage tank 8.

The switching state of the flow path switching valve 51 is the first switching state in which the a port, the b port and the c port are mutually opened, and the second switching state in which the a port and the c port are opened and the b port is cut off. Including the switching state. In the first switching state, the hot water supply pipe 13, the tank upper pipe 21, and the hot water side pipe 50 communicate with each other. In the second switching state, the hot water supply pipe 13 does not communicate with the tank upper pipe 21, and the hot water supply pipe 13 communicates with the hot water side inlet of the hot water supply mixing valve 22 via the hot water side pipe 50. The switching state of the flow path switching valve 51 may further include a third switching state in which the port b and the port c are opened and the port a is shut off.

FIG. 2 is a diagram showing the flow of hot water during the hot water storage operation of the hot water storage type water heater 35 shown in FIG. The hot water storage operation is an operation in which hot water heated by the HP unit 7, that is, high-temperature water is stored in the hot water storage tank 8. The control unit 36 controls the start and stop of the hot water storage operation according to the amount of residual hot water or the amount of heat stored in the hot water storage tank 8. The control unit 36 controls the operation of the hot water storage operation as follows. The flow path switching valve 51 is in the first switching state. The three-way valve 11 communicates between the a and c ports. The four-way valve 18 communicates between the cd ports. The HP unit 7 and the circulation pump 12 are operated, and the low-temperature water at the lower part in the hot water storage tank 8 passes through the water outlet 8b, the low-temperature pipe 10, the three-way valve 11, the circulation pump 12 and the HP outbound pipe 14, and exchanges heat with the water refrigerant. It flows into the vessel 3. For example, the high temperature water of 65 ° C. generated by heating this low temperature water in the water refrigerant heat exchanger 3 is the HP return pipe 15, the four-way valve 18, the hot water supply pipe 13, the flow path switching valve 51, and the upper part of the tank. It flows into the hot water storage tank 8 from the hot water introduction outlet 8d through the pipe 21. In this way, the hot water supply pipe 13 forms a part of the return pipe that serves as a water channel from the HP unit 7 to the hot water storage tank 8. When the hot water storage operation is executed, high-temperature water is stored from the upper part to the lower part of the hot water storage tank 8, and the layer of the high-temperature water gradually becomes thicker. When the amount of hot water stored or the amount of heat stored in the hot water storage tank 8 detected by the hot water storage temperature sensors 42 and 43 exceeds a predetermined amount, the control unit 36 ends the hot water storage operation.

Immediately after the HP unit 7 is started, the temperature of the hot water flowing out of the HP unit 7 does not rise sufficiently. Therefore, immediately after the HP unit 7 is started, the control unit 36 communicates between the a-c ports of the four-way valve 18 and allows the hot water flowing out of the HP unit 7 to pass through the first bypass pipe 16 to the hot water storage tank 8. It may flow into the lower part. In this way, the first bypass pipe 16 forms a part of the return pipe that serves as a water channel from the HP unit 7 to the hot water storage tank 8.

In the following description, the state in which the water from the water source supplied to the first water supply pipe 9a is not supplied to the hot water storage type water heater 35 is referred to as a "water cut state", and the state in which water is supplied from the water source to the first water supply pipe 9a is referred to as "water supply pipe 9a". It is called "normal water supply state". FIG. 3 is a diagram showing the flow of hot water during the hot water supply operation in the normal water supply state of the hot water storage type water heater 35 shown in FIG. The control unit 36 controls the operation of this hot water supply operation as follows. The flow path switching valve 51 is in the first switching state. When the user opens the faucet 90, the hot water in the hot water storage tank 8 flows from the water source through the first water supply pipe 9a and the third water supply pipe 9c into the hot water storage tank 8. It passes through the path switching valve 51 and the hot water side pipe 50, and flows into the hot water side inlet of the hot water supply mixing valve 22. Further, water from the water source passes through the first water supply pipe 9a and the second water supply pipe 9b and flows into the water side inlet of the hot water supply mixing valve 22. The hot water mixed by the hot water supply mixing valve 22 is supplied to the faucet 90 through the hot water supply pipe 24, the hot water supply plug 34, and the external hot water supply pipe 91.

FIG. 4 is a diagram showing the flow of hot water from the hot water storage tank 8 to the faucet 90 when the hot water storage type water heater 35 shown in FIG. 1 is out of water. The control unit 36 has a function of determining a water outage state. When the water is cut off, the control unit 36 controls as follows. The flow path switching valve 51 is put into the second switching state. The three-way valve 11 communicates between the a and c ports. The four-way valve 18 communicates between the b and d ports.

If the hot water in the hot water storage tank 8 is higher than the faucet 90 in the water outage state, the hot water in the hot water storage tank 8 can be taken from the faucet 90 due to the head difference without driving the circulation pump 12. It becomes. As an example, it is assumed that the height of the hot water storage tank 8 is 2.0 m, the height of the faucet 90 is 1.0 m, and the head difference is 1.0 m. In this case, the hot water in the hot water storage tank 8 can be taken from the faucet 90 as shown in FIG. That is, when the faucet 90 is opened, the water flowing out from the water outlet 8b of the hot water storage tank 8 is sent to the low temperature pipe 10, the three-way valve 11, the HP going pipe 14, the circulation pump 12, the second bypass pipe 17, the four-way valve 18, and so on. It is supplied to the faucet 90 through the hot water pipe 13, the flow path switching valve 51, the hot water side pipe 50, the hot water supply mixing valve 22, the hot water supply pipe 24, the hot water supply plug 34, and the external hot water supply pipe 91. As a result, the user can take out the hot water in the hot water storage tank 8 from the faucet 90 in the house and use it when the water is cut off. At this time, since the user does not have to go to the place of the tank unit 33, the hot water in the hot water storage tank 8 can be easily used.

When the hot water in the hot water storage tank 8 is supplied to the faucet 90 in a water cut state, the inside of the hot water storage tank 8 becomes negative pressure, the negative pressure operating valve 56 opens, and the outside air flows into the hot water storage tank 8. In the above example, water can be taken from the faucet 90 without driving the circulation pump 12 until the head difference disappears, that is, until the water surface in the hot water storage tank 8 becomes the same height as the faucet 90.

Further, if the circulation pump 12 is driven in the water cut state, the entire amount of hot water in the hot water storage tank 8 can be taken from the faucet 90 by the route shown in FIG. 4, regardless of the head difference from the faucet 90.

Since the water from the water source is not supplied to the hot water supply mixing valve 22 in the water cutoff state, the hot water supply mixing valve 22 cannot adjust the hot water supply temperature. When the water is cut off, the control unit 36 may control the hot water supply mixing valve 22 so that the hot water side inlet is fully open and the water side inlet is fully closed. This makes it possible to increase the flow rate of water flowing to the faucet 90.

Assuming that the flow path switching valve 51 is set to the first switching state and the circulation pump 12 is driven in the water cut state, the hot water flowing through the hot water supply pipe 13 is not only in the hot water side pipe 50 but also in the tank upper pipe 21. It flows and flows into the hot water storage tank 8 from the hot water introduction outlet 8d. At this time, since hot water flows through the flow path from the tank upper pipe 21 to the pressure relief valve 55 and the negative pressure operating valve 56, the negative pressure operating valve 56 cannot operate under negative pressure. As a result, although the inside of the hot water storage tank 8 has a negative pressure, the outside air cannot be supplied into the hot water storage tank 8, so that water cannot be taken from the faucet 90. On the other hand, in the present embodiment, water can be taken from the faucet 90 by putting the flow path switching valve 51 in the second switching state.

According to this embodiment, in the event of an emergency water outage, the user can take in the hot water in the hot water storage tank 8 from the faucet 90 that is normally used, which is excellent convenience. Sex is obtained. Since the circulation pump 12 used for the hot water storage operation can be used as a water supply pump when the water is cut off, it is not necessary to add a pump.

In the present embodiment, by providing the second bypass pipe 17, the water of the HP going pipe 14 can flow into the hot water supply pipe 13 without passing through the HP unit 7 when the water is cut off. Therefore, the pressure loss in the water supply path when the water is cut off is reduced, which is advantageous in increasing the flow rate of the water flowing to the faucet 90. However, in the present disclosure, the second bypass pipe 17 may not be provided, and water may be supplied from the hot water storage tank 8 to the faucet 90 via the HP unit 7 when the water is cut off.

When the user selects the water outage mode on the remote controller 44 or other user interface, the control unit 36 may determine the water outage state. Further, the control unit 36 may determine the water outage state by using a predetermined sensor. For example, the control unit 36 may determine that the water is cut off when the flow rate detected by the bath flow rate sensor 45 when the bath solenoid valve 26 is opened is lower than the reference.

When the detected flow rate of the hot water supply flow rate sensor 52 becomes equal to or higher than the first reference in the water outage state, it may be determined that the faucet 90 has been opened, and the control unit 36 may start the circulation pump 12. This makes it easier to take water from the faucet 90. The value of the first reference may be, for example, 2 L / min.

If the detected flow rate of the hot water supply flow rate sensor 52 falls below the second reference while the circulation pump 12 is being driven in the water outage state, it is determined that the faucet 90 is closed, and the control unit 36 stops the circulation pump 12. You may. As a result, the power consumption of the circulation pump 12 can be suppressed. The value of the second reference may be, for example, 2 L / min.

When the water outage state is detected, the control unit 36 may operate the circulation pump 12 and stop the operation of the circulation pump 12 after a predetermined time has elapsed.

When the control unit 36 determines that the water outage state has been resolved, the control unit 36 puts the flow path switching valve 51 into the first switching state. As a result, the flow path configuration is automatically restored to the normal operation such as the hot water storage operation of FIG. 2 or the hot water supply operation of FIG. 3, so that the convenience is further improved.

If the detected flow rate of the hot water supply flow rate sensor 52 becomes equal to or higher than the third reference while the circulation pump 12 is not operating in the water outage state, the control unit 36 may determine that the water outage state has been resolved. The value of the third reference is a value larger than that of the first reference and the second reference, and may be, for example, 10 L / min. By automatically determining whether or not the water supply is cut off according to the detected flow rate of the hot water supply flow rate sensor 52, the convenience in an emergency is further improved.

The amount of water that can be taken from the faucet 90 when the water is cut off is equal to or less than the capacity of the hot water storage tank 8. The hot water storage type water heater 35 may include a total amount detecting means for detecting the total amount of water flowing through the hot water supply pipe 24 in a water outage state (hereinafter, referred to as “total water supply amount at the time of water outage)). For example, when the water supply is cut off, the control unit 36 integrates the detected flow rate of the hot water supply flow rate sensor 52, so that the total water supply amount at the time of the water supply cutoff can be calculated. When the total amount of water supplied at the time of water outage reaches a standard set to be equal to or less than the capacity of the hot water storage tank 8, the control unit 36 may prohibit the operation of the circulation pump 12. For example, when the capacity of the hot water storage tank 8 is 370 liters, the value of the above reference may be 350 liters. By doing so, it is possible to prevent unnecessary operation of the circulation pump 12 while effectively utilizing the hot water in the hot water storage tank 8 when the water is cut off.

Embodiment 2.
Next, the second embodiment will be described with reference to FIGS. 5 and 6, but the differences from the above-described first embodiment will be mainly described, and the elements common to or corresponding to the above-mentioned elements will be described. The same reference numerals are given to simplify or omit common descriptions. FIG. 5 is a diagram showing a hot water storage type water heater 35 according to the second embodiment. The hot water storage type water heater 35 of the present embodiment includes a flow path switching valve 53 instead of the flow path switching valve 51 of the first embodiment. The flow path switching valve 53 has an a port, a b port, and a c port. The first bypass pipe 16 connects the a port of the four-way valve 18 and the a port of the flow path switching valve 53. The tank lower pipe 9d connects the tank lower opening 8a and the b port of the flow path switching valve 53. The c port of the flow path switching valve 53 is connected to the third water supply pipe 9c.

The switching state of the flow path switching valve 53 is the first switching state in which the a port, the b port and the c port are mutually opened, and the second switching state in which the a port and the c port are opened and the b port is cut off. Including the switching state. In the first switching state, the first bypass pipe 16, the tank lower pipe 9d, and the third water supply pipe 9c communicate with each other. In the second switching state, the first bypass pipe 16 does not communicate with the tank lower pipe 9d, and the first bypass pipe 16 passes through the third water supply pipe 9c and the second water supply pipe 9b to the water side of the hot water supply mixing valve 22. Communicate to the entrance. The switching state of the flow path switching valve 53 may further include a third switching state in which the port b and the port c are opened and the port a is shut off.

During normal operation, the control unit 36 puts the flow path switching valve 53 into the first switching state. During the hot water supply operation, water is supplied from the water source into the hot water storage tank 8 through the first water supply pipe 9a, the third water supply pipe 9c, the flow path switching valve 53, and the tank lower pipe 9d.

FIG. 6 is a diagram showing the flow of hot water from the hot water storage tank 8 to the faucet 90 in the water cutoff state of the hot water storage type water heater 35 shown in FIG. When the water is cut off, the control unit 36 controls as follows. The flow path switching valve 53 is put into the second switching state. The three-way valve 11 communicates between the a and c ports. The four-way valve 18 communicates between the a and b ports. When the faucet 90 is opened and the circulation pump 12 is driven, the water flowing out from the water outlet 8b of the hot water storage tank 8 is discharged from the low temperature pipe 10, the three-way valve 11, the HP going pipe 14, the circulation pump 12, and the second bypass pipe 17. , Four-way valve 18, first bypass pipe 16, flow path switching valve 53, third water supply pipe 9c, second water supply pipe 9b, hot water supply mixing valve 22, hot water supply pipe 24, hot water supply plug 34, and external hot water supply pipe 91. , Is supplied to the faucet 90. At this time, the flow path switching valve 53 reliably prevents the hot water flowing through the first bypass pipe 16 from flowing into the hot water storage tank 8.

When the water is cut off, the control unit 36 may control the hot water supply mixing valve 22 so that the water side inlet is fully open and the hot water side inlet is fully closed. This makes it possible to increase the flow rate of water flowing to the faucet 90.

1 Compressor, 3 Water refrigerant heat exchanger, 4 Expansion valve, 5 Refrigerator piping, 6 Air heat exchanger, 7 HP unit, 8 Hot water storage tank, 8a Tank lower port, 8b Water outlet, 8c Water inlet, 8d Hot water Introductory outlet, 9a 1st water supply pipe, 9b 2nd water supply pipe, 9c 3rd water supply pipe, 9d tank lower pipe, 10 low temperature pipe, 11 three-way valve, 12 circulation pump, 13 hot water supply pipe, 14 HP outbound pipe, 15 HP Return piping, 16 1st bypass piping, 17 2nd bypass piping, 18 4-way valve, 20a piping, 20b piping, 21 Tank upper piping, 22 Hot water supply mixing valve, 23 Bath mixing valve, 24 Hot water supply piping, 25 Bath piping, 26 Electromagnetic valve for bath, 27 Bath going pipe, 28 Bath return piping, 29 Bath circulation pump, 30 Bath, 31 Pressure reducing valve, 33 Tank unit, 34 Hot water tap, 35 Hot water storage type water supply machine, 36 Control unit, 37 Bath going temperature Sensor, 38 Bath return temperature sensor, 42, 43 Hot water storage temperature sensor, 44 Remote control, 45 Bath flow sensor, 50 Hot water side piping, 51 Flow path switching valve, 52 Hot water supply flow rate sensor, 53 Flow path switching valve, 54 Branch, 55 Pressure relief valve, 56 Negative pressure actuating valve, 60 Bath heat exchanger, 60a primary side flow path, 60b secondary side flow path, 90 faucet, 91 External hot water supply pipe

Claims (12)

A heating means to heat water and
A hot water storage tank for storing hot water heated by the heating means, and
A mixing valve that allows hot water that is a mixture of hot water that has flowed in from the hot water side inlet and water that has flowed in from the water side inlet to flow into the hot water supply pipe.
A water circuit through which hot water flows and
It is a hot water storage type water heater equipped with
The water circuit
An outgoing pipe that serves as a water channel from the hot water storage tank to the heating means,
A return pipe that serves as a water channel from the heating means to the hot water storage tank,
A circulation pump that allows water to flow through the forward pipe and the return pipe,
Flow switching valve and
With
The switching state of the flow path switching valve is a first switching state in which the return pipe communicates with the hot water storage tank, and the return pipe communicates with the hot water side inlet or the water side inlet without communicating with the hot water storage tank. Hot water storage type water heater including the second switching state. The water circuit includes a tank upper pipe connected to the upper part of the hot water storage tank.
In the first switching state, the return pipe, the tank upper pipe, and the hot water side inlet communicate with each other, and in the second switching state, the return pipe does not communicate with the tank upper pipe and the hot water side. The hot water storage type water heater according to claim 1, which communicates with the entrance. The water circuit includes a tank lower pipe connected to the lower part of the hot water storage tank.
In the first switching state, the return pipe, the tank lower pipe, and the water side inlet communicate with each other, and in the second switching state, the return pipe does not communicate with the tank lower pipe and the water side. The hot water storage type water heater according to claim 1, which communicates with the entrance. When the circulation pump is driven while the flow path switching valve is in the second switching state, the water in the hot water storage tank is discharged into the outgoing pipe, the circulation pump, the return pipe, the flow path switching valve, the mixing valve, and the like. The hot water storage type water heater according to any one of claims 1 to 3, which is supplied to a faucet downstream of the hot water supply pipe through the hot water supply pipe. The hot water storage type according to any one of claims 1 to 4, wherein the water circuit includes a bypass pipe capable of allowing water in the outgoing pipe to flow into the return pipe without passing through the heating means. Water heater. It is provided with a control unit having a function of determining a water outage state in which water from a water source is not supplied to the hot water storage type water heater and a function of controlling the operation of the hot water storage type water heater.
The hot water storage type water heater according to any one of claims 1 to 5, wherein when the water is cut off, the control unit puts the flow path switching valve in the second switching state. The hot water storage type water heater according to claim 6, wherein when the user selects the water cutoff mode on the user interface, the control unit determines the water cutoff state. It is equipped with a hot water supply flow rate sensor that detects the hot water supply flow rate, which is the flow rate of water flowing through the hot water supply pipe.
The hot water storage type water heater according to claim 6 or 7, wherein the control unit activates the circulation pump when the hot water supply flow rate becomes equal to or higher than the first reference in the water cutoff state. It is equipped with a hot water supply flow rate sensor that detects the hot water supply flow rate, which is the flow rate of water flowing through the hot water supply pipe.
The hot water storage type according to any one of claims 6 to 8, wherein the control unit stops the circulation pump when the hot water supply flow rate becomes equal to or less than the second reference while the circulation pump is being driven in the water cutoff state. Water heater. It is equipped with a hot water supply flow rate sensor that detects the hot water supply flow rate, which is the flow rate of water flowing through the hot water supply pipe.
The hot water storage type water heater according to any one of claims 6 to 9, wherein when the hot water supply flow rate becomes equal to or higher than the third reference in the water cutoff state, the control unit determines that the water cutoff state has been resolved. The hot water storage type water heater according to any one of claims 6 to 10, wherein when the water cutoff state is resolved, the control unit puts the flow path switching valve into the first switching state. A total amount detecting means for detecting the total amount of water flowing through the hot water supply pipe in the water cutoff state is provided.
The hot water storage type water heater according to any one of claims 6 to 11, wherein when the total amount reaches a standard equal to or less than the capacity of the hot water storage tank, the control unit prohibits the operation of the circulation pump.

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