JP2013221705A - Storage type water heater - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a storage type water heater hard to degrade its assembling performance due to increase of components, and increase costs, while achieving effects of improving efficiency of the water heater by recovering bath heat and suppressing energy loss in boiling-up.SOLUTION: A storage type water heater includes a hot water storage tank 3, a water supply pipe 7 connected to a lower section of the hot water storage tank and a water source, a heat exchanger 16 exchanging heat between warm water stored in the hot water storage tank and warm water of a bath, a four-way valve 9 switching a flow channel between the hot water storage tank and the heat exchanger, a tank upper pipe 11 connected to an upper section of the hot water storage tank and the four-way valve, an expanded water discharge pipe 10 connected to a pressure release valve 14 and the four-way valve, a reheating heat source circulation pipe 12 connected to an intermediate section of the hot water storage tank and the four-way valve, and a heat recovering pipe 13 connected to a downstream side of a pressure reduction valve 8 in the water supply pipe and the four-way valve, and further includes a control section 50 for switching and controlling the four-way valve to a first flow channel configuration and a second flow channel configuration.

Description

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

  The conventional hot water storage type hot water heater is a three-way valve provided in the middle of the recirculation path of the bath water using the hot water in the hot water storage tank as a heat source, and the flow path can be switched between the upper and lower parts of the hot water storage tank. It is configured to improve the efficiency of the hot water heater using the waste heat of the bath water by performing bathing and heat recovery (bath heat recovery) of the bath water to the water below the hot water storage tank. . (Patent Document 1)

  In addition, the conventional hot water storage type water heater uses a four-way valve to discharge the expansion water from the lower part of the tank for a predetermined time during boiling to reduce the energy loss at the time of boiling, and at the upper part of the hot water storage tank, Air generated in the hot water storage tank due to a decrease in solubility due to boiling by providing a time to open the open / close valve while boiling the hot water in the hot water tank by boiling means, and communicating with the pressure relief valve through the open / close valve. In the following, the air in the tank) is extracted. (Patent Document 2)

JP 2010-196992 A JP 2012-37079 A

  However, in the configuration of Patent Document 1, a new three-way valve and piping connecting from the three-way valve to the lower part of the tank are required for bath heat recovery, and there are problems of lowering assembly and increasing costs due to an increase in parts.

  Further, in the configuration of Patent Document 2, it is necessary to newly provide an on-off valve for venting the air in the tank and a pipe that communicates the tank upper part with the relief valve. Even in this case, the assemblage decreases and the cost increases due to an increase in parts. There was a problem.

  The present invention has been made in order to solve such a problem, and it is possible to improve the efficiency of a water heater by recovering bath heat and to obtain an effect of suppressing energy loss at the time of boiling while assembling by increasing the number of parts. It aims at obtaining the hot water storage type hot water heater which is hard to produce the fall of this and a cost rise.

  A hot water storage tank having heating means, one end connected to the lower part of the hot water storage tank, a water supply pipe connected to the water source at the other end through a pressure reducing valve, and hot water stored in the hot water storage tank and hot water in the bath A heat exchanger for exchanging heat, a four-way valve for switching a flow path between the hot water storage tank and the heat exchanger, a tank upper pipe connected at one end to the upper part of the hot water storage tank and connected at the other end to the four-way valve, One end is connected to the pressure relief valve, the other end is connected to the four-way valve, and one end is connected to the middle part between the upper and lower parts of the hot water storage tank, the other end is connected to the four-way valve, A heating heat source circulation pipe having a heat exchanger and a heat source side circulation pump in the middle, and a heat recovery pipe having one end connected to the downstream side of the pressure reducing valve in the water supply pipe and the other end connected to the four-way valve, The four-way valve is connected to the expansion water discharge pipe and the heat recovery pipe, A first flow path configuration in which the upper piping and the additional heat source circulation piping communicate, and a second flow path configuration in which the expansion water discharge pipe and the tank upper piping communicate, and the additional heat source piping and the heat recovery piping communicate with each other. And a control unit that performs switching control.

  Advantageous Effects of Invention According to the present invention, a hot water storage type hot water heater that is less likely to cause a decrease in assemblability or an increase in cost due to an increase in parts while improving the efficiency of the water heater by recovering bath heat and suppressing the loss of energy during boiling. Can be obtained.

It is a block diagram of the hot water storage type water heater of Embodiment 1 of the present invention. It is a figure which shows the flow of the hot water at the time of the boiling operation of Embodiment 1. FIG. It is a figure which shows the flow of the hot water at the time of the boiling operation of Embodiment 1. FIG. It is a figure which shows the flow of the hot water at the time of the chasing operation of Embodiment 1. FIG. FIG. 3 is a diagram showing a flow of hot water during the bath heat recovery operation of the first embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

Embodiment 1.
A hot water storage type water heater in a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a configuration diagram of a hot water storage type water heater 100 according to Embodiment 1 of the present invention, and includes a heat pump unit 1 as a heating means and a hot water storage tank unit 2 having a hot water storage tank 3 for storing hot water. .

  In FIG. 1, the heat pump unit 1 has a built-in refrigerant circuit (not shown), can take in heat of the air by a heat pump cycle, heat the supplied hot water, and boil it up. An HP forward piping 4 having an HP circulation pump 6 is connected to the lower part of the hot water storage tank 3, and the other end of the HP forward piping is connected to the water inlet side of the heat pump unit 1. An HP return pipe 5 is connected to the outlet side of the heat pump unit 1, and the other end of the HP return pipe is connected to the upper part of the hot water storage tank 3.

  One end of the water supply pipe 7 is connected to a water source, the other end is built in the hot water storage tank unit 2, and is connected to a pressure reducing valve 8 that reduces the water pressure to a predetermined value or less, and supplies city water to the pressure reducing valve 8 side. From the pressure reducing valve 8, the water supply pipe 7 is connected to a hot water supply mixing valve 30 (described later), connected to a first water supply branch pipe 7 a for supplying city water to the hot water supply mixing valve 30, and a lower part of the hot water storage tank 3. Branching from the lower part of 3 to a second water supply branch pipe 7 b for supplying city water to the hot water storage tank 3. (FIG. 1 shows a case where a part of them is shared)

  The four-way valve 9 incorporated in the hot water storage tank unit 2 has a tank upper pipe 11 connected at one end to the upper part of the hot water storage tank 3, and the hot water in the hot water storage tank 3 and air in the tank can be discharged at one end inside the hot water storage tank 3. An expansion water discharge pipe 10 connected to a relief valve 14 which opens when the pressure of the water reaches a predetermined value or more is released to the outside, and a three-way valve 18 whose one end can be switched to connection to the upper or lower part of the hot water storage tank 3. A heat exchanger 16 connected to the hot water storage tank 3 for exchanging heat with the bath water in the bathtub 20 and a heat source side circulation pump 17 for circulating the hot water in the hot water storage tank 3 to the heat exchanger 16 are provided. The fired heat source circulation pipe 12 and one end thereof are connected to the heat recovery pipe 13 connected to the second water supply branch pipe 7b. The recirculation heat source circulation pipe 12 has a flow path to the hot water storage tank 3 divided into a plurality of (two in FIG. 1) by the three-way valve 18, and the hot water storage near the connection position with the upper side of the hot water storage tank 3. On the tank 3, an upper temperature sensor 3a for detecting the temperature of the hot water in the hot water storage tank 3 near the connection position is provided. Similarly, a lower temperature sensor 3c for detecting the temperature of hot water in the hot water storage tank 3 near the connection position is provided on the hot water storage tank 3 in the vicinity of the connection position with the lower side of the hot water storage tank 3. The return position of the reheating heat source circulation pipe 12 to the hot water storage tank 3 is switched and determined by appropriately controlling the three-way valve 18 which will be described later.

  The four-way valve 9 is connected to the expansion water discharge pipe 10 and the heat recovery pipe 13, and the tank upper pipe 11 and the additional heat source circulation pipe 12 communicate with each other. ”And the“ second flow path configuration (communication of arrow B in the drawing) ”in which the expansion water discharge pipe 10 and the tank upper pipe 11 communicate with each other, and the additional heat source pipe 12 and the heat recovery pipe 13 communicate with each other. The control unit 50, which will be described later, is configured to be switchable.

  On the secondary side of the heat exchanger 16, a bath circulation pipe that circulates the bath water in the bathtub 20 in order to exchange heat with hot water flowing through the primary side of the heat exchanger 16 (the additional heat source circulation pipe 12 side). 21 is connected, the bath water in the bathtub 20 is drawn by a bath-side circulation pump 22 provided in the middle of the bath circulation pipe 21, and the bath water is detected by a bath temperature sensor 23 provided on the bath circulation pipe 21. The temperature can be detected. Note that, in a general hot water storage type hot water heater, a bath hot water supply that supplies a desired amount of hot water to the bathtub 20 side at a desired temperature by a path having a configuration similar to a hot water supply path to a hot water supply destination in a hot water mixing valve 30 described later. A path is built in, and the configuration is the same in this embodiment, but illustration and description are omitted.

  In addition, an intake pipe 15 is provided for communication so as to bypass the flow path of the four-way valve 9 between the expansion water discharge pipe 10 and the tank upper pipe 11, and the intake pipe 15 is provided with a check valve 15 a on the way. The flow of the fluid from the relief valve 14 side to the tank upper pipe 11 side through the expansion water discharge pipe 10 is allowed by the check valve 15a, but the reverse flow is restricted.

  If for some reason the pressure in the hot water storage tank 3 becomes lower than the pressure outside the hot water storage tank 3, that is, if the pressure in the hot water storage tank 3 becomes negative and the four-way valve 9 is in the first flow path configuration. In this case, air can be quickly introduced into the hot water storage tank 3 from the outside of the hot water storage tank 3 through the relief valve 14, the expansion water discharge pipe 10, the intake pipe 15, and the tank upper pipe 11. Destruction can be prevented.

  The hot water mixing valve 25 incorporated in the hot water storage tank unit 2 is supplied with hot hot water at the upper part of the hot water storage tank 3 from a high temperature hot water supply pipe 26 connected at one end to the upper part of the hot water storage tank 3, and at one end of the hot water storage tank. Hot water storage from a tank hot water pipe 27 connected to an intermediate part between the upper part and the lower part of 3 (preferably a position lower than the highest position among the connecting parts of the reheating heat source circulation pipe 12 to the hot water storage tank 3). The supply of hot water staying in the intermediate part of the tank 3 is received, the mixing ratio is adjusted so as to reach a predetermined temperature under the control of the control unit 50 described later, and the hot water is discharged to the intermediate temperature hot water supply pipe 28. The intermediate hot water hot water supply pipe 28 includes a temperature sensor 29 capable of detecting the hot water temperature in the vicinity of the connection position with the intermediate hot water mixing valve 25, and the other end is connected to the hot water supply mixing valve 30. An intermediate temperature sensor 3b for detecting the temperature of hot water in the hot water storage tank 3 in the vicinity of the connection position is provided on the hot water storage tank 3 in the vicinity of the connection position between the intermediate hot water pipe 27 and the intermediate portion of the hot water storage tank 3. Is provided.

  The hot water mixing valve 30 mixes the city water from the first water supply branch pipe 7a and the hot water from the medium temperature hot water outlet pipe 28 under a control of the control unit 50 described later so as to have a predetermined hot water temperature. Is supplied to the hot water supply pipe 31. The hot water supply pipe 31 is provided with a temperature sensor 32 capable of detecting a hot water temperature in the vicinity of a connection position with the hot water mixing valve 30, and the other end is connected to a hot water supply destination such as a faucet or a shower.

  The control unit 50 is built in the hot water storage tank unit 2 and configured to be able to communicate with a remote controller 51 installed in an indoor kitchen or bathroom. The control unit 50 includes the above-described actuators (four-way valve 9, three-way valve 18, medium hot water mixing valve 25, hot water mixing valve 30) and sensors (upper temperature sensor 3a, intermediate temperature sensor 3b, lower temperature sensor 3c, bath temperature). Sensor 23, temperature sensors 29, 32) and heat pump unit 1, and the desired hot water supply temperature set by the user with remote controller 51 and the hot water in hot water storage tank 3 are detected by the detection signals of the sensors. By controlling each actuator and heat pump unit 1 for each operation such as reheating and bath heat recovery, while controlling the boiling temperature and the boiling amount, the filling temperature and filling amount to the bathtub 20 Realize.

About the hot water storage type water heater 100 of the first embodiment configured as described above, hereinafter, FIG.
The operation and action will be described with reference to FIG. In the following description of operations, the control unit 50 determines and controls these operations. Moreover, in each figure, the same code | symbol is attached | subjected to FIG.

  First, boiling operation of hot water in the hot water storage tank 3 will be described with reference to FIGS. 2 and 3 are diagrams showing a state of the boiling operation of the hot water storage type hot water heater according to Embodiment 1 of the present invention. During the boiling operation, the state of FIG. 2 and the state of FIG. The operation which changes suitably is performed. The same applies to the following figures, but there is a flow of hot water, and the main piping is expressed thickly in the description, and the flow direction of the hot water is expressed by an arrow along the piping.

  In FIG. 2, when the boiling operation is started, the control unit 50 operates the heat pump unit 1 and subsequently operates the HP circulation pump 6. Then, the water in the lower part of the hot water storage tank 3 flows from the lower part of the hot water storage tank 3 into the HP outgoing pipe 4, reaches the heat pump unit 1, is heated and heated by the heat pump unit 1, and is heated by the HP return pipe 5. Return to the top of the. If this is continued, hot water is stored in a state in which high-temperature hot water is gradually stacked from the upper part of the hot water storage tank. At this time, as shown in FIG. 2, the four-way valve 9 has a first flow path configuration, and a second water supply branch pipe 7 b connected to the lower part of the hot water storage tank 3, a heat recovery pipe 13 connected thereto, and a four-way The relief valve 14 is in communication with the lower part of the hot water storage tank 3 via the valve 9 and the expansion water discharge pipe 10. As described above, the second water supply branch pipe 7b serves as a communication path for discharging the expansion water from the lower part of the hot water tank 3 to the release valve 14 side, in addition to the function of supplying city water to the lower part of the hot water tank 3. Also works. Therefore, it is not necessary to provide a dedicated pipe for each, which contributes to an improvement in assembling and cost reduction of the hot water storage type water heater.

  If boiling is continued in the state of FIG. 2, the hot water for volume expansion due to the rise in the temperature of the hot water in the hot water storage tank 3 is discharged from the lower part of the hot water storage tank 3 through the relief valve 14. Instead, the low-temperature water at the bottom of the hot water storage tank 3 will be discharged, and the expanded water will not be discharged as high-temperature hot water. A boiling operation can be performed. On the other hand, the tank air generated by boiling gradually accumulates in the upper part of the hot water storage tank 3.

  The tank air accumulated in the upper part of the hot water storage tank 3 is discharged out of the system by switching the flow path to the state shown in FIG. FIG. 3 is a diagram showing another state of the boiling operation according to Embodiment 1 of the present invention. The difference from FIG. 2 is the flow path switching state of the four-way valve 9. In FIG. 3, the four-way valve 9 is switched to the second flow path configuration, whereby the hot water storage tank is connected via the tank upper pipe 11, the four-way valve 9, and the expansion water discharge pipe 10 connected to the upper part of the hot water storage tank 3. 3 and the relief valve 14 communicate with each other. By continuing boiling in this state, the air in the tank is discharged out of the system from the upper part of the hot water storage tank 3 via the relief valve 14. At this time, because of the operation of the check valve 15a, there is no flow of hot water or the like from the intake pipe 15 to the relief valve 14, so that hot hot water at the upper part of the hot water storage tank 3 is not discharged unnecessarily.

  In boiling operation, the effect of the state of FIG. 2 (low-temperature water at the bottom of the hot water storage tank 3 is discharged by switching to the state of FIG. Since the expanded water is not discharged as hot water, it is possible to perform an efficient boiling operation without wasting energy during boiling) and the effect in the state of FIG. It is possible to discharge the tank air generated by boiling).

  Note that how to switch between the state shown in FIG. 2 and the state shown in FIG. 3 during the boiling operation may be set as appropriate on the manufacturer side of the hot water storage type hot water heater. For example, the necessary time for discharging the air in the tank generated when the hot water storage tank 3 is fully boiled is confirmed and set in advance, and one boiling is performed while boiling in the state of FIG. The time when the state shown in FIG. 3 is reached may be a time necessary for discharging the air in the tank. Alternatively, after performing the state of FIG. 2 for a predetermined time, boiling may be repeatedly performed by sandwiching the state of FIG. 3 for a predetermined time shorter than that.

  Moreover, you may comprise so that the time which makes it the state of FIG. 3, ie, the required time for discharging | emitting tank air, can be changed with feed water temperature (temperature of city water) and the target temperature of boiling. For example, when the feed water temperature is low and the boiling temperature is high, the amount of air generated in the tank increases because the solubility change due to the temperature difference is greater than in other cases. For this reason, you may comprise so that the time set to the state of FIG. 3 may be set long. According to this, even if the amount of air generated in the tank changes due to changes in the feed water temperature or the boiling temperature, the air in the tank can be properly discharged, and hot water mixed with air from a hot water supply destination such as a faucet can be discharged. It is possible to more appropriately eliminate the defects that are discharged.

  Next, the chasing operation of the bathtub 20 according to the first embodiment of the present invention will be described with reference to FIG. FIG. 4 is a diagram illustrating a flow path in the bath water purging operation state in the bathtub 20 according to the first embodiment of the present invention. In addition, about the piping structure regarding the hot water filling from the hot water storage tank 3 to the bathtub 20, and its operation | movement, illustration and description are abbreviate | omitted as mentioned above, and hot water filling is made in the bathtub 20, and it demonstrates as a case where it chases. To do.

  In FIG. 4, when the chasing operation is started, the control unit 50 operates the bath-side circulation pump 22 to circulate the bath water in the bathtub 20 into the bath circulation pipe 21. The temperature of the bath water is detected and grasped by the control unit 50 by the bath temperature sensor 23. Subsequently, the control unit 50 places the four-way valve 50 in the first flow path configuration, switches the three-way valve 18 to the flow path on the upper side of the hot water storage tank 3, and starts the heat source side circulation pump 17. Then, the hot water at the upper part of the hot water storage tank 3 passes through the tank upper pipe 11, the four-way valve 9, the reheating heat source circulation pipe 12, the heat exchanger 16, and the three-way valve 18 and returns to the upper side of the hot water storage tank 3. Circulate with. As a result, the hot water in the upper part of the hot water storage tank 3 and the bath water are heat-exchanged by the heat exchanger 16 so that the bath water is heated and heated, returns to the bathtub 20 side, and circulates again from the bathtub 20 to the bath-side circulation pipe 21. To do. This operation is continued until the bath temperature sensor 23 reaches a predetermined temperature set by the user with the remote controller 51, and when the predetermined temperature is reached, the heat source side circulation pump 17 and the bath side circulation pump 22 are stopped to complete the chasing. To do. Although the temperature of the returned hot water from the heat exchanger 16 is lowered to some extent due to the heat exchange in the reheating, returning the hot water to the upper side of the hot water storage tank 3 mixes with the hot water at the upper part of the hot water storage tank 3. The hot water can be stored as hot water in the upper part of the hot water storage tank 3 in a state where the temperature does not decrease so much. Thereby, the hot water can be used for the hot water from the hot water storage tank 3 to the faucet or the like, and the energy of the hot water after the heat exchange in the reheating can be effectively used.

  In the above description, the case where the hot water returning to the hot water storage tank 3 via the heat exchanger 16 is returned to the upper side of the hot water storage tank 3 by the three-way valve 18 has been described. When the amount of hot water is relatively small, or when the temperature difference between the lower temperature sensor 3c and the upper temperature sensor 3a of the hot water storage tank 3 is small and the temperature of both is relatively high (that is, the hot water storage tank 3 is almost hot and full) The temperature of the hot water returned to the reheating is lowered to the upper part of the hot water storage tank 3 so that the temperature of the hot water in the upper part is lowered or the temperature after the reheating from the upper part of the hot water storage tank 3 to the intermediate hot water. If there is a possibility that the temperature stratification in the hot water storage tank 3 is destroyed and stirred by adding hot water with reduced water, the three-way valve 18 may be switched to the lower side of the hot water storage tank 3. The upper, middle, and lower temperature states of the hot water storage tank 3 are detected by the upper temperature sensor 3a, the intermediate temperature sensor 3b, and the lower temperature sensor 3c, respectively, and can be calculated and understood by the control unit 50.

  For example, without using the three-way valve 18, the hot water return flow path to the hot water storage tank 3 is relocated to the upper side or the lower side of the hot water storage tank 3 (or an intermediate portion between the upper part and the lower part). The system may be constructed in a state where the three-way valve 18 is eliminated and fixed in advance. According to this, an effect corresponding to the selected fixed return position can be obtained, and the three-way valve 18 is not required, so that it is possible to improve the assemblability and reduce the cost. In addition, when setting a return flow path in the intermediate part of the hot water storage tank 3, in order to acquire the effect by the bath heat collection | recovery to the intermediate temperature water mentioned later, it is set as the position higher than the tank intermediate temperature water pipe 27. preferable.

  Next, the heat recovery operation (bath heat recovery operation) from the bath water of the bathtub 20 according to Embodiment 1 of the present invention will be described with reference to FIG. FIG. 5 is a diagram showing the flow path in the state of recovering bath heat from the bath water in the bathtub 20 according to Embodiment 1 of the present invention. In FIG. 5, it is assumed that there is remaining hot water after the bath 20 is filled with hot water and the bathing is completed.

  In FIG. 5, for example, when the user operates the remote controller 51 to instruct an operation for recovering bath heat, the control unit 50 operates the bath-side circulation pump 22 to circulate bath water (remaining hot water) in the bathtub 20. Circulate in the pipe 21. The temperature of the bath water is detected and grasped by the control unit 50 by the bath temperature sensor 23. The control unit 50 compares the detected temperature (temperature of remaining hot water) at this time with the detected temperature of the lower temperature sensor 3c of the hot water tank 3, that is, the temperature of hot water at the lower part of the hot water tank 3, and the temperature of hot water at the lower part of the hot water tank 3 If the temperature is lower than the temperature of the remaining hot water and it is determined that heat recovery is possible, the operation proceeds to the next operation. Otherwise, the bath heat recovery is not performed and the bath-side circulation pump 22 is stopped and the operation is terminated. Here, as to whether the three-way valve 18 is switched to the lower side or the upper side of the hot water storage tank 3, the temperature detected by the upper temperature sensor 3 a and the lower temperature sensor 3 c and the temperature of the remaining hot water, that is, the detection by the bath temperature sensor 23. The controller compares and determines the temperature. Thereby, the position of the hot water storage tank 3 that can recover the bath heat can be grasped, and an appropriate bath heat recovery operation can be performed. Therefore, if the temperature detected by the upper temperature sensor 3a is lower than the temperature of the remaining hot water, the three-way valve 18 may be switched to the upper side.

  When it is determined that the bath heat can be recovered, the control unit 50 subsequently places the four-way valve 50 in the second flow path configuration, switches the three-way valve 18 to the flow path on the lower side of the hot water storage tank 3, and turns the heat source side circulation pump 17 on. to start. Then, the low-temperature hot water in the lower part of the hot water storage tank 3 passes through the second water supply branch pipe 7b, the heat recovery pipe 13, the four-way valve 9, the additional heat source circulation pipe 12, the heat exchanger 16, and the three-way valve 18, and passes through the hot water storage tank. 3 circulates in the flow path returning to the lower side. As a result, the heat exchanger 16 exchanges heat between the relatively low temperature hot water at the bottom of the hot water tank 3 and the bath water (remaining hot water), so that the hot water at the lower side of the hot water tank 3 is heated and heated. As described above, the second water supply branch pipe 7b discharges hot water for recovering bath heat from the lower part of the hot water storage tank 3 to the heat exchanger 16 side in addition to the action of supplying city water to the lower part of the hot water storage tank 3. It also acts as a communication path when doing so. Therefore, it is not necessary to provide a dedicated pipe for each, which contributes to an improvement in assembling and cost reduction of the hot water storage type water heater.

  The bath heat recovery operation is performed only while the bath heat can be recovered, that is, only when the temperature of the remaining hot water is higher than the temperature of the hot water led from the lower part of the hot water storage tank 3 to the heat exchanger 16, and the bath heat can be recovered. Stop when it's gone. Alternatively, it may be continued for a predetermined time or a predetermined heat recovery amount. As a result, the thermal energy of the remaining hot water in the bathtub 20 can be recovered in the low-temperature hot water at the bottom of the hot water storage tank 3, so that the thermal energy of the remaining hot water that would otherwise be thrown away is recovered in the hot water in the hot water storage tank 3 to provide hot water, etc. The energy required for boiling can be saved, and the operation efficiency of the hot water storage type water heater is improved.

  In the above example, the three-way valve 18 is switched to the lower side of the hot water tank 3, and the three-way valve 18 of the second water supply branch pipe 7 b and the additional heat source circulation pipe 12 connected to the lower part of the hot water tank 3. The bath heat recovery operation between the hot water between the lower side connection positions of the hot water storage tank 3 and the remaining hot water in the bathtub 20 has been described. For example, the detected temperature of the upper temperature sensor 3a is higher than the temperature of the remaining hot water. In other cases, the three-way valve 18 is switched to the upper side and the connection position on the upper side of the hot water storage tank 3 via the three-way valve 18 of the additional heat source circulation pipe 12 and the hot water storage tank 3 of the second water supply branch pipe 7b are switched. The bath heat recovery operation may be performed with the hot water between the connection positions and the remaining hot water of the bathtub 20. According to this, the hot water which collected the thermal energy of the remaining hot water of the bathtub 20 by the bath heat recovery operation is stored up to a position above the tank hot water pipe 27 in the hot water storage tank 3, and the tank hot water pipe 27, the hot recovered hot water can be taken out as medium temperature water and used for hot water supply or the like, so that the operation efficiency of the hot water storage type hot water heater is improved.

  As described above, according to the first embodiment, the efficiency of the hot water storage water heater by recovering the bath heat and the effect of suppressing the energy loss at the time of boiling are reduced, and the assemblability is reduced due to the increase in parts. In addition, a hot water storage type hot water heater that is less likely to increase costs can be obtained.

100 Hot water storage type hot water heater 1 Heat pump unit (heating means)
2 Hot water storage tank unit 3 Hot water storage tank 3a Upper temperature sensor 3b Intermediate temperature sensor 3c Lower temperature sensor 4 HP forward piping 5 HP return piping 6 HP circulation pump 7 Water supply piping 7a First water supply branch piping 7b Second water supply branch piping 8 Pressure reducing valve 9 Four-way valve 10 Expansion water discharge pipe 11 Tank upper pipe 12 Reheating heat source circulation pipe 13 Heat recovery pipe 14 Relief valve 15 Intake pipe 15a Check valve 16 Heat exchanger 17 Heat source side circulation pump 18 Three-way valve 20 Bathtub 21 Bath Circulation piping 22 Bath-side circulation pump 23 Bath temperature sensor 25 Medium hot water mixing valve 26 High temperature hot water piping 27 Tank medium hot water piping 28 Medium hot water hot water piping 29 Temperature sensor 30 Hot water mixing valve 31 Hot water piping 32 Temperature sensor 50 Control unit 51 Remote control

Claims (3)

A hot water storage tank having heating means;
One end is connected to the lower part of the hot water storage tank, and a water supply pipe having the other end connected to a water source via a pressure reducing valve in the middle,
A heat exchanger for exchanging heat between hot water stored in the hot water storage tank and hot water in the bath;
A four-way valve that switches a flow path between the hot water storage tank and the heat exchanger;
A tank upper pipe connected at one end to the upper part of the hot water storage tank and connected at the other end to the four-way valve;
An expansion water discharge pipe having one end connected to the pressure relief valve and the other end connected to the four-way valve;
One end is connected to an intermediate part between the upper and lower parts of the hot water storage tank, the other end is connected to the four-way valve, and a heating heat source circulation pipe provided with the heat exchanger and a heat source side circulation pump in the middle,
A heat recovery pipe connected at one end to the downstream side of the pressure reducing valve in the water supply pipe and connected at the other end to the four-way valve;
The four-way valve,
The expansion water discharge pipe and the heat recovery pipe communicate with each other, and the tank upper pipe and the additional heat source circulation pipe communicate with each other.
A second flow path configuration in which the expansion water discharge pipe and the tank upper pipe communicate with each other, and the additional heat source pipe and the heat recovery pipe communicate with each other.
A control unit for switching control;
A hot water storage type water heater characterized by comprising The controller is
When performing reheating to heat the hot water of the bath with hot water in the hot water storage tank, the four-way valve is controlled to the first flow path form,
2. The hot water storage according to claim 1, wherein when performing bath heat recovery for recovering heat from hot water in the bath to hot water in the hot water storage tank, the four-way valve is controlled in the second flow path form. Type water heater.   An intake pipe having a check valve that communicates the expansion water discharge pipe and the tank upper pipe and restricts the flow of fluid from the tank upper pipe side to the expansion water discharge pipe in the middle. The hot water storage type water heater according to claim 1 or 2.

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