JP2015140956A - Hot water storage type water heater - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hot water storage type water heater capable of recovering heat in a bathtub efficiently according to timing at which a user drains bathtub water.SOLUTION: A hot water storage type water heater includes: a hot water storage tank 4 for storing hot water; bathtub water level detection means (water level sensor 13) for detecting a water level of a bathtub 90; heat exchange means (reheating heat exchanger 18) for performing heat exchange of the bathtub water and the hot water in the hot water storage tank 4; drain time estimation means (control unit 22) for storing water level data of the bathtub 90 by the bathtub water level detection means being associated with time, and for estimating drain time of the bathtub 90 based on the water level data; and control means (control unit 22) for controlling a bathtub heat recovery operation for performing heat recovery from the bathtub 90 to the hot water in the hot water storage tank 4 by the heat exchange means. The control means controls the bathtub heat recovery operation based on residual time which is a difference between the drain estimation time estimated by the drain time estimation means and the present time.

Description

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

  There is known a hot water storage type hot water heater capable of performing a bathtub heat recovery operation for recovering heat of hot water remaining in a bathtub after being used for bathing into hot water in a hot water storage tank.

  In Patent Document 1 below, residual hot water heat recovery means for performing bath heat recovery operation, a water level sensor provided in the bath circulation circuit of the bathtub for detecting the end of hot water filling and bathing, and the bath temperature for detecting the end of reheating A bath use state storage unit that stores the last 7 days and the day of the bathing time due to the rise of the bathtub water level by the water level sensor and the end time of hot water filling and chasing by the water level sensor and bath temperature sensor A technique is disclosed in which the bath use state storage unit selects the latest bathing detection time and drives the remaining hot water heat recovery means at a time obtained by adding a predetermined time to this time.

JP2011-122760A (6th page, FIG. 3)

  In the technique of Patent Document 1 described above, bathing is detected by detecting a change in the water level of the bathtub using a water level sensor, and a predetermined time is added to the latest bathing detection time of the past 7 days and the day, and then the bathtub. The heat recovery operation starts automatically. For this reason, there is an advantage that it is not necessary for the user to manually start the bathtub heat recovery operation. However, the technique of Patent Document 1 has the following problems.

  In order to recover the bathtub heat, it is necessary that the water level of the bathtub is above a certain level. That is, the user needs to perform the bathtub heat recovery operation before removing the stopper of the bathtub and draining the bathtub water. The timing of draining the bathtub water varies depending on the user. In the technique of Patent Document 1, the bathtub heat recovery operation is automatically started from the time when the predetermined time is added to the latest bathing detection time in the past 7 days and the same day, but the timing of draining the bathtub water is In the case of a user who tends to be fast, the bathtub water may be drained before the bathtub heat recovery operation is completed. In such a case, there is a problem that the heat of the bathtub cannot be sufficiently recovered.

  The present invention has been made to solve the above-described problems, and provides a hot water storage type hot water heater that can efficiently recover the heat of the bathtub according to the timing when the user drains the bathtub water. For the purpose.

  A hot water storage type water heater according to the present invention includes a hot water storage tank for storing hot water, a bathtub water level detection means for detecting the water level of the bathtub, a heat exchange means for performing heat exchange between the bathtub water and the hot water in the hot water storage tank, and the bathtub water level. The water level data of the bathtub by the detection means is stored in relation to the time, and the heat from the bathtub to the hot water in the hot water storage tank by the heat exchanging means by the drain time estimation means for estimating the drain time of the bathtub based on the water level data. A control means for controlling the bathtub heat recovery operation for performing recovery, and the control means is based on the remaining time which is the difference between the estimated drainage time estimated by the drainage time estimation means and the current time, and The recovery operation is controlled.

  ADVANTAGE OF THE INVENTION According to this invention, according to the timing which a user drains bathtub water, it becomes possible to collect | recover the heat | fever of a bathtub efficiently.

It is a block diagram which shows the hot water storage type water heater of Embodiment 1 of this invention. It is a flowchart which shows the control action of the bathtub heat recovery driving | operation in Embodiment 1 of this invention.

Embodiments of the present invention will be described below with reference to the drawings.
Embodiment 1 FIG.
FIG. 1 is a configuration diagram illustrating a hot water storage type water heater according to Embodiment 1 of the present invention. As shown in FIG. 1, the hot water storage type water heater 1 according to the first embodiment includes a hot water storage unit 2 and a heat pump unit 3. The hot water storage unit 2 and the heat pump unit 3 are connected via a heat pump inlet pipe 29, a heat pump outlet pipe 30, and electrical wiring (not shown).

  The heat pump unit 3 functions as a heating means for heating water. The heat pump unit 3 includes a compressor that compresses a refrigerant, a water-refrigerant heat exchanger that heats water using a high-temperature and high-pressure refrigerant compressed by the compressor, and an expansion device that expands and decompresses the high-pressure refrigerant after heat dissipation, such as the atmosphere. Although a refrigeration cycle apparatus in which a low-temperature side heat exchanger that absorbs heat from the low-temperature heat source is connected by refrigerant piping is mounted, illustration is omitted.

  The heating means in the present invention is not limited to a configuration using a refrigeration cycle such as the heat pump unit 3, and may use an electric heater, a solar heat collector, or the like. It may be used in combination.

  Inside the housing of the hot water storage unit 2 are a hot water storage tank 4, a pressure reducing valve 5, a heat pump circulation pump 6, a bypass valve 7, a hot water supply mixing valve 8, a bath mixing valve 9, a bath pipe 10, a water supply pipe 11, and a bath circulation pump 12. A water level sensor 13, a flow switch 14, a follow-up pump 15, a follow-up switching valve 16, a follow-up upper pipe 17, a follow-up heat exchanger 18, a follow-up lower pipe 19, a control unit 22 and the like are mounted.

  The hot water storage tank 4 stores hot water by forming a temperature stratification in which the upper side is hot and the lower side is low. The water supply pipe 11 is supplied with water from a water source such as an external water supply. In the middle of the water supply pipe 11, a pressure reducing valve 5 for reducing the water source pressure to a predetermined pressure is provided. The water supply pipe 11 is bifurcated on the downstream side of the pressure reducing valve 5, one of which is connected to the lower part of the hot water storage tank 4. The water supplied from the water source flows into the lower part of the hot water storage tank 4 through the water supply pipe 11 so that the hot water storage tank 4 is always kept in a full state. In the hot water storage tank 4, the water source pressure regulated by the pressure reducing valve 5 acts. The other water supply pipes branched by the pressure reducing valve 5 are connected to the hot water supply mixing valve 8 and the bath mixing valve 9, respectively.

  The hot water storage tank 4 is provided with a plurality of temperature sensors at different heights. In the first embodiment, the upper tank temperature thermistor 27 is installed in the upper region of the hot water storage tank 4 and the lower tank temperature thermistor 28 is installed in the lower region of the hot water storage tank 4. You may install in the tank 4 further.

  The heat pump inlet pipe 29 connects the lower part of the hot water storage tank 4 and the water inlet of the heat pump unit 3. A heat pump circulation pump 6 is disposed in the middle of the heat pump inlet pipe 29. The bypass valve 7 has one inlet and two outlets. The heat pump outlet pipe 30 connects the water outlet of the heat pump unit 3 and the inlet of the bypass valve 7. One outlet of the bypass valve 7 is connected to the upper part of the hot water storage tank 4 via the upper pipe 31, and the other outlet of the bypass valve 7 is connected to the lower part of the hot water storage tank 4 via the bypass pipe 32. The bypass valve 7 connects the heat pump outlet pipe 30 to the upper pipe 31 and closes the bypass pipe 32 side, and the bypass valve 7 connects the heat pump outlet pipe 30 to the bypass pipe 32 and closes the upper pipe 31 side. It is possible to switch to a flow path form.

  Here, the boiling operation of the hot water storage type water heater 1 will be described. The boiling operation is an operation for increasing the amount of stored hot water (heat storage amount) in the hot water storage tank 4 by circulating the hot water in the hot water storage tank 4 through the heat pump unit 3 and heating it. In the boiling operation, the heat pump unit 3 and the heat pump circulation pump 6 are operated, and the bypass valve 7 is switched to the first flow path configuration. In the boiling operation, water led out from the lower part of the hot water storage tank 4 by the heat pump circulation pump 6 is sent to the heat pump unit 3 through the heat pump inlet pipe 29 and heated by the water-refrigerant heat exchanger in the heat pump unit 3. Become hot water. This high temperature water flows into the upper part of the hot water storage tank 4 through the heat pump outlet pipe 30, the bypass valve 7 and the upper pipe 31. By such boiling operation, high temperature water is stored in the hot water storage tank 4 from above.

  One end of a medium-temperature water discharge pipe 20 is connected to an intermediate region in the height direction of the hot water storage tank 4. The other end of the medium temperature water take-out pipe 20 is connected to the hot water supply mixing valve 8. The intermediate hot water taken out from the hot water storage tank 4 to the intermediate hot water take-out pipe 20 is sent to the hot water supply mixing valve 8.

  The high temperature water stored in the hot water storage tank 4 is sent to the hot water mixing valve 8 and the bath mixing valve 9 through the high temperature water take-out pipe 33 connected to the upper part of the hot water storage tank 4, respectively. The hot water supply mixing valve 8 can adjust the mixing ratio of the high-temperature water supplied from the high-temperature water extraction pipe 33, the medium-temperature water supplied from the medium-temperature water extraction pipe 20, and the low-temperature water supplied from the water-supply pipe 11. ing. Hot water whose temperature is adjusted by being mixed by the hot water supply mixing valve 8 is supplied to a demand end such as a shower, a sink, and a wash basin through the hot water supply pipe 21. The bath mixing valve 9 can adjust the mixing ratio of the high-temperature water supplied from the high-temperature water take-out pipe 33 and the low-temperature water supplied from the water supply pipe 11.

  The follow-up heat exchanger 18 is a heat exchanger that performs heat exchange between the bathtub water stored in the bathtub 90 and the hot water in the hot water storage tank 4. The bathtub 90 is connected to the hot water storage unit 2 via the bath circulation pipe 34. The bath circulation pipe 34 extends from the bathtub 90 into the hot water storage unit 2, passes through the bath circulation pump 12, the water level sensor 13, the flow switch 14, and the follow-up heat exchanger 18 in this order in the hot water storage unit 2, and then into the bathtub 90. A return circulation channel is provided. A bath return temperature thermistor 25 is installed in the bath circulation pipe 34 between the bath circulation pump 12 and the water level sensor 13, and the bath circulation pipe 34 between the follow-up heat exchanger 18 and the bathtub 90 is connected to the bath. A temperature thermistor 26 is provided. The bath pipe 10 is connected to the bath circulation pipe 34 between the bath temperature thermistor 26 and the follow-up heat exchanger 18. The hot water whose temperature is adjusted by being mixed by the bath mixing valve 9 is supplied from the bath pipe 10 to the bath 90 through the bath circulation pipe 34. A bath electromagnetic valve 37 that opens and closes the bath piping 10 is installed in the middle of the bath piping 10. In the first embodiment, the water level sensor 13 corresponds to a bathtub water level detection means.

  The hot water storage tank 4 is further connected with a follow-up upper pipe 17 and a follow-up lower pipe 19. One end of the follow-up upper pipe 17 has a height between a position where the upper pipe 31 and the high temperature water take-out pipe 33 are connected to the hot water storage tank 4 and a position where the intermediate hot water take-out pipe 20 is connected to the hot water tank 4. It is connected to the hot water storage tank 4 at a position. The other end of the tracking upper pipe 17 is connected to the tracking switching valve 16. One end of the trailing lower pipe 19 is located at a height between a position where the water supply pipe 11 and the heat pump inlet pipe 29 are connected to the hot water storage tank 4 and a position where the intermediate temperature water discharge pipe 20 is connected to the hot water storage tank 4. Is connected to the hot water storage tank 4. The other end of the tracking lower pipe 19 is connected to the tracking switching valve 16. The follow-up switching valve 16 is connected to a follow-up heat exchanger 18 via a follow-up pipe 35. The follow-up switching valve 16 communicates the follow-up upper pipe 17 with the follow-up pipe 35 and closes the follow-up lower pipe 19 and the follow-up lower pipe 19 with the follow-up pipe 35. It is possible to switch to the second flow path configuration that closes the tracking upper pipe 17 side.

  A follow-up middle pipe 36 is further connected to the hot water storage tank 4. One end of the follow-up middle pipe 36 is at a height between the position where the follow-up upper pipe 17 is connected to the hot water storage tank 4 and the position where the intermediate hot water discharge pipe 20 is connected to the hot water storage tank 4. 4 is connected. The other end of the follow-up middle pipe 36 is connected to the follow-up heat exchanger 18. A tracking pump 15 is disposed in the middle of the tracking middle pipe 36.

  In the first embodiment, the bath circulation pump 12, the bath circulation pipe 34, the tracking pump 15, the tracking switching valve 16, the tracking upper piping 17, the tracking lower piping 19, the tracking piping 35, and the tracking tracking. The middle pipe 36 corresponds to a heat exchange means for performing heat exchange between the bathtub water and the hot water in the hot water storage tank 4.

  The control unit 22 is configured by, for example, a microcomputer and the like, and includes a storage unit including a ROM, a RAM, a nonvolatile memory, and the like, an arithmetic processing device (CPU) that executes arithmetic processing based on a program stored in the storage unit, And an input / output port for inputting / outputting external signals to / from the arithmetic processing unit. The control unit 22 includes a heat pump unit 3, a heat pump circulation pump 6, a bypass valve 7, a hot water supply mixing valve 8, a bath mixing valve 9, a bath circulation pump 12, a water level sensor 13, a flow switch 14, an exhaust pump 15, a bath return temperature thermistor. 25, a bath temperature thermistor 26, an upper tank temperature thermistor 27, a lower tank temperature thermistor 28, and a bath electromagnetic valve 37 are electrically connected to each other. Further, the control unit 22 is connected to a remote controller 24 that is a user interface device through a communication line 23 so as to be able to communicate with each other. The user can set the target temperature of the hot water supply mixing valve 8, the target temperature of the bath mixing valve 9, the target temperature when chasing the bathtub 90, and the like by operating the remote controller 24. The control unit 22 controls the operation of the hot water storage type hot water heater 1 based on information received from the remote controller 24 and information detected by sensors. Moreover, the control part 22 has the timer 22a which clocks time.

  Next, the hot water operation of the hot water storage type water heater 1 will be described. When the user issues a hot water instruction from the remote controller 24, the control unit 22 opens the bath electromagnetic valve 37 and causes the amount of hot water instructed by the remote controller 24 to flow through the bath pipe 10. The bath mixing valve 9 mixes the high temperature water from the upper part of the hot water storage tank 4 and the low temperature water from the water supply pipe 11, and adjusts the mixing ratio so that the temperature is instructed by the remote controller 24. After flowing a certain amount of hot water, the bath circulation pump 12 is circulated, and the presence or absence of bath water is determined by the flow switch 14. When there is no bathtub water, an error is displayed on the remote controller 24, and when there is bathtub water, the hot water is finished.

  Next, the chasing operation of the hot water storage type water heater 1 will be described. In the chasing operation, when the bathtub water stored in the bathtub 90 dissipates heat and the temperature drops, the hot water in the upper region of the hot water storage tank 4 having a temperature higher than that of the bathtub water is exchanged with the bathtub water, It is control which raises the temperature of bathtub water. First, the controller 22 circulates the bath water in the bath circulation pipe 34 by the bath circulation pump 12 and measures the temperature of the bath water by the bath return temperature thermistor 25. When the temperature of the bathtub water is below a certain temperature and the detected temperature of the upper tank temperature thermistor 27 is equal to or higher than the certain temperature, the control unit 22 starts a follow-up operation. In the chasing operation, the chasing switching valve 16 is switched to the chasing upper pipe 17 side while the bath water is circulating in the bath circulation pipe 34 by the bath circulation pump 12, and the chasing pump 15 is operated. In this manner, heat exchange between the hot water led out from the hot water storage tank 4 to the follow-up upper pipe 17 and the bath water is performed by the follow-up heat exchanger 18. The hot water whose temperature has been lowered by applying heat to the bathtub water in the follow-up heat exchanger 18 returns to the hot water storage tank 4 through the follow-up middle pipe 36. This heat exchange is carried out until the temperature detected by the bath return temperature thermistor 25 reaches a certain temperature or higher.

  Next, the bathtub heat recovery operation of the hot water storage type hot water heater 1 will be described. Contrary to the chasing operation described above, the bathtub heat recovery operation performs heat exchange between the water in the lower region of the hot water storage tank 4 whose temperature is lower than that of the bathtub water and the bathtub water, thereby reducing the amount of heat of the bathtub water. It is control which collect | recovers in the hot water storage tank 4. FIG. When the user finishes bathing, the control unit 22 determines the number of times of bathing (the number of bathers) from the number of times of detection of the water level sensor 13 after the hot water filling, and the data is stored in the past certain period (for example, the past week). Compare with the number of baths (the number of bathers). When the number of bathing times per day (the number of bathers) reaches the specified number, the control unit 22 determines that all the bathing has been completed, and causes the bath circulation pump 12 to circulate the bath water to the bath circulation piping 34, The bath water temperature is measured by the bath return temperature thermistor 25. When the temperature of the bathtub water is higher than the detected temperature of the lower tank temperature thermistor 28 by a certain value or more, the control unit 22 starts the bathtub heat recovery operation. In the bathtub heat recovery operation, the chasing switch valve 16 is switched to the chasing lower pipe 19 while the bath water is circulating in the bath circulation pipe 34 by the bath circulation pump 12, and the chasing pump 15 is operated. In this manner, the heat exchange between the water led out from the hot water storage tank 4 to the follow-up lower pipe 19 and the bath water is performed by the follow-up heat exchanger 18. The hot water whose temperature has risen due to the heat of the bathtub water received by the follow-up heat exchanger 18 returns to the hot water storage tank 4 through the follow-up middle pipe 36. This heat exchange is carried out until the temperature detected by the bath return temperature thermistor 25 falls below a certain temperature. The hot water storage type water heater of the first embodiment is characterized by control of the heat recovery rate in the bathtub heat recovery operation or control of the start timing of the bathtub heat recovery operation.

  FIG. 2 is a flowchart showing the control operation of the bathtub heat recovery operation in the first embodiment. In step S1 of FIG. 2, the control unit 22 first performs the bathing operation described above by starting the bath automatic function. After completion of the hot water operation, the control unit 22 stores the water level data of the bathtub 90 detected by the water level sensor 13 in association with the time as step S2, and changes in the detected value of the water level sensor 13 during automatic bathing. The amount is integrated and the total value is calculated. At this time, when the fluctuation of the detection value of the water level sensor 13 at one time is equal to or less than a predetermined value, the control unit 22 does not enter or exit the bathtub 90 but merely pumps out hot water from the bathtub 90. It is assumed that it is only, and it is not added to the total value of the fluctuation amount. And the control part 22 judges whether the total value is more than predetermined value V as step S3, when adding the variation | change_quantity of the detected value of the water level sensor 13 to a total value. If the total value is not greater than or equal to the predetermined value V in step S3, the control unit 22 determines that the bathing of all members has not been completed and returns to step S2 again. On the other hand, when the said total value is more than predetermined value V by step S3, it determines with the control part 22 having completed the bathing of all, and transfers to step S4. The predetermined value V is, for example, the maximum value of the total value obtained by integrating the fluctuation amount of the detected value of the water level sensor 13 at the time of automatic end of the data in the past fixed period (for example, the past one week). In step S4, the control unit 22 waits for a preset standby time A from the time when the detection value of the water level sensor 13 last fluctuates. This waiting time A is a spare time in case the bathing has not ended.

  After the standby time A has elapsed in step S4, the control unit 22 sets in advance a difference between the estimated drainage time, which is the time when the bathtub 90 is expected to be drained, and the current time as step S5. It is determined whether or not there is a threshold value of N minutes or more. In the following description, the difference between the estimated drainage time and the current time is referred to as “remaining time”. In the first embodiment, the control unit 22 has a function as drainage time estimation means for estimating (predicting) drainage estimation time as follows. The control unit 22 considers the time at which the water level of the bathtub 90 has decreased so that the water level detection by the water level sensor 13 becomes impossible on each day of the past fixed period (for example, the past week), as the drain time, Accumulate data. Then, the control unit 22 uses the earliest time as the estimated drainage time in the past drainage time data.

  Alternatively, the control unit 22 may estimate (predict) the estimated drainage time as follows. The control unit 22 determines whether or not everyone's bathing has ended as described above, and sets the time at which it is determined that everyone's bathing has ended as the bathing end time, and for each past fixed period (for example, the past week). Accumulate the data of the bathing end time of the day. Further, the control unit 22 accumulates the data of the past drainage time as described above, and stores the data of the time difference between the drainage time and the bathing end time of each day (that is, the time from the bathing end time to the draining time). accumulate. And the control part 22 determines drainage estimation time based on the bathing end time of the day and the data of the past time difference. For example, the control part 22 uses the time which added the shortest time among the data of the past time difference to the bathing end time of the day as drainage estimation time. According to such a method, when the variation in drainage time is large as a characteristic of the user, but the variation in time from the bathing end time to the drainage time tends to be relatively small, the estimated drainage time is more accurate. Can be estimated (expected).

  If the remaining time until the estimated drainage time is less than N minutes in step S5, that is, if there is not enough time to perform the normal bath heat recovery operation, the control unit 22 proceeds to step S6, Automatic bathing is stopped and bathing end time data is accumulated. Next, as step S7, the control unit 22 performs a high-output bath heat recovery operation that causes the bath circulation pump 12 and the follow-up pump 15 to operate at a higher output than the normal bath heat recovery operation. In the high-output bath heat recovery operation, the circulation flow rate of the bath water circulating in the follow-up heat exchanger 18 and the hot water in the hot water storage tank 4 is increased and the heat recovery speed is increased as compared with the normal bath heat recovery operation. Therefore, the high-output bathtub heat recovery operation can be completed in a shorter time than the normal bathtub heat recovery operation. Thus, in this Embodiment 1, when the remaining time to drainage estimation time is short, it replaces with a normal bathtub heat recovery driving | operation, and implements the high output bathtub heat recovery driving | operation which only requires a short time. Thus, it is possible to reliably suppress the drainage of the bathtub 90 from being started during the bathtub heat recovery operation. Therefore, even if the remaining time until the estimated drainage time is short, the bathtub heat can be sufficiently recovered. For example, assuming that the circulation flow rate at the time of maximum rotation of the bath circulation pump 12 is 7 L / min and the maximum amount of hot water by bathing is 210 L, 30 minutes is required to circulate all the bathtub water in the bathtub 90. Take it. In this case, by setting N minutes = 30 minutes, it is possible to circulate almost all of the bathtub water and sufficiently recover the bathtub heat.

  On the other hand, when the remaining time up to the estimated drainage time is N minutes or more in step S5, that is, when there is sufficient time to perform a normal bathtub heat recovery operation, the control unit 22 proceeds to step S8. To do. In step S8, the control unit 22 determines whether or not a preset standby time B has elapsed from the time when the detection value of the water level sensor 13 last fluctuated. This waiting time B is a spare time in preparation for when bathing has not been completed, and is longer than the waiting time A in step S4.

  If the standby time B has not elapsed in step S8, the process returns to step S5. Even if the process proceeds to step S8, if the remaining time until the estimated drainage time is less than N minutes before the standby time B elapses, the process proceeds to step S6 and step S7. .

  On the other hand, when the standby time B has elapsed in step S8, the control unit 22 proceeds to step S9, stops automatic bathing, and accumulates bathing end time data. In this case, next, as step S10, it is determined whether or not the boiling operation is being performed. If the boiling operation is being performed in step S10, the process proceeds to step S11. In step S11, the control unit 22 determines whether or not the remaining time until the estimated drainage time is equal to or longer than a preset time of M minutes. If the remaining time up to the estimated drainage time is M minutes or longer in step S11, the control unit 22 does not start the bathtub heat recovery operation and returns to step S10. In this way, the controller 22 delays the start timing of the bathtub heat recovery operation when the boiling operation is being performed and the remaining time until the estimated drainage time is M minutes or longer. By such control, the following effects can be obtained.

  When the bathtub heat recovery operation is performed, the water temperature in the lower region of the hot water storage tank 4 rises. Therefore, if the bathtub heat recovery operation is performed during the boiling operation, the temperature of the water sent to the heat pump unit 3 may increase. The heat pump unit 3 has better operating efficiency as the temperature of the water before heating is lower. For this reason, when the boiling operation is being performed, the operation efficiency of the heat pump unit 3 is improved when the bathtub heat recovery operation is not performed. When the remaining time until the estimated drainage time is M minutes or longer, the remaining time is sufficiently long, so that the bathtub heat recovery operation can be completed even if the start timing of the bathtub heat recovery operation is delayed. Therefore, in the first embodiment, when the boiling operation is being performed and the remaining time up to the estimated drainage time is M minutes or longer, the control unit 22 delays the start timing of the bathtub heat recovery operation, The bathtub heat recovery operation is started after completion of the raising operation. Thereby, it becomes possible to fully collect | recover bathtub heat, without reducing the operating efficiency of the heat pump unit 3 in a boiling operation.

  If the boiling operation is not being performed in step S10, or if the remaining time until the estimated drainage time is less than M minutes in step S11, the process proceeds to step S12. In step S <b> 12, the control unit 22 determines whether or not the remaining time until the estimated drainage time is equal to or longer than a preset threshold value of L minutes. When the remaining time until the estimated drainage time is less than L minutes in step S12, the control unit 22 performs a normal bathtub heat recovery operation as step S13. In this normal bathtub heat recovery operation, the bath circulation pump 12 and the follow-up pump 15 are operated at a preset normal output. On the other hand, when the remaining time until the estimated drainage time is equal to or longer than L minutes in step S12, the control unit 22 lowers the bath circulation pump 12 and the follow-up pump 15 in step S14 as compared with the normal bath heat recovery operation. A low-power bathtub heat recovery operation is carried out.

  In the low-output bathtub heat recovery operation, compared to the normal bathtub heat recovery operation, the circulation flow rate of the bathtub water circulating in the follow-up heat exchanger 18 and the hot water in the hot water storage tank 4 is reduced, and the heat recovery rate is reduced. Therefore, the low-power bathtub heat recovery operation requires a longer time than the normal bathtub heat recovery operation. The L minutes are set as a time during which the low-power bathtub heat recovery operation can be completed. In the low output bathtub heat recovery operation, since the circulating flow rate of the hot water in the hot water storage tank 4 is low, it is possible to suppress the stirring of the remaining hot water inside the hot water storage tank 4 and therefore compared to the normal bath heat recovery operation. Higher recovery efficiency can be obtained. In the first embodiment, when the remaining time until the estimated drainage time is long enough to complete the low-output bath heat recovery operation, the low-output bath heat recovery operation is substituted for the normal bath heat recovery operation. By carrying out, the recovery efficiency of the bathtub heat can be further improved. For example, assuming that the circulation flow rate by the bath circulation pump 12 during the most efficient bathtub heat recovery operation is 1 L / min and the maximum hot water volume by bath automatic is 210 L, all the bathtub water in the bathtub 90 is circulated. It takes 210 minutes to complete. In that case, by setting L minutes = 210 minutes, it becomes possible to circulate all the bath water and recover the bath heat sufficiently in the low-power bath heat recovery operation.

  On the other hand, when the remaining time until the estimated drainage time is less than L minutes in step S12, that is, when there is not enough time to perform the low-output bath heat recovery operation, the normal bath heat recovery operation is performed. By doing, it can suppress reliably that drainage of bathtub 90 will be started in the middle of bathtub heat recovery operation. For this reason, it becomes possible to fully collect | recover bathtub heat.

  Next, the stop condition of the bathtub heat recovery operation in step S7, step S13, and step S14 will be described. The control unit 22 proceeds from step S7, step S13, or step S14 to step S15. In step S15, the control unit 22 confirms whether or not there is a rapid fluctuation (abrupt water level decrease) in the detection value of the water level sensor 13 during the bathtub heat recovery operation. Then, when there is a sudden change (abrupt water level drop), it is determined that drainage is started, and the process proceeds to step S16. In step S <b> 16, the control unit 22 stops the bathtub heat recovery operation and accumulates data on the drainage time.

  In step S15, when there is no sudden change (rapid water level drop) of the detection value of the water level sensor 13, the process proceeds to step S17. In step S <b> 17, the control unit 22 measures the temperature of the bathtub water with the bath return temperature thermistor 25 and confirms whether the bathtub water temperature is higher than the detected temperature of the lower tank temperature thermistor 28 by a certain temperature C or more. If the bath water temperature is higher than the detected temperature of the lower tank temperature thermistor 28 by a certain temperature C or more in step S17, the bath heat can be recovered, so the control unit 22 continues the bath heat recovery operation, and step S15. Return to.

  On the other hand, when the temperature difference between the bath water temperature and the detected temperature of the lower tank temperature thermistor 28 becomes less than the constant temperature C in step S17, the control unit 22 determines that it is difficult to recover the bath heat any more. In step S18, the bathtub heat recovery operation is stopped.

  After stopping the bathtub heat recovery operation in step S18, until the start of drainage, the control unit 22 periodically drives the bath circulation pump 12 and sets the temperature of the bath water by the bath return temperature thermistor 25 in step S19. Measure and check again whether the bath water temperature is higher than the detected temperature of the lower tank temperature thermistor by a certain temperature C or more. When the bath water temperature is higher than the detected temperature of the lower tank temperature thermistor 28 by a certain temperature C or more in this step S19, the bath heat can be recovered, so the control unit 22 returns to step S14 and returns to the low output bath. Perform heat recovery operation.

  On the other hand, when the temperature difference between the bath water temperature and the detected temperature of the lower tank temperature thermistor 28 is less than the constant temperature C in step S19, the control unit 22 makes a sudden change in the detected value of the water level sensor 13 in step S20. When there is (a sudden drop in water level), it is determined that drainage is started, and the process proceeds to step S21. In step S <b> 21, the control unit 22 accumulates drainage time data.

  Thus, in this Embodiment 1, after finishing the 1st bathtub heat recovery driving | operation, until the start of drainage, the control part 22 determines whether the heat | fever of the bathtub 90 is recoverable in step S19. judge. Then, when it is determined in step S19 that the heat of the bathtub 90 can be recovered, the control unit 22 returns to step S14 and performs the second bathtub heat recovery operation (low output bathtub heat recovery operation). In the first embodiment, when the second bathtub heat recovery operation is possible, it is possible to recover more bathtub heat by performing the second bathtub heat recovery operation in this way. Become.

DESCRIPTION OF SYMBOLS 1 Hot water storage type water heater, 2 Hot water storage unit, 3 Heat pump unit, 4 Hot water storage tank, 5 Pressure reducing valve, 6 Heat pump circulation pump, 7 Bypass valve, 8 Hot water mixing valve, 9 Bath mixing valve, 10 Bath piping, 11 Hot water piping, 12 Bath circulation pump, 13 water level sensor, 14 flow switch, 15 follow-up pump, 16 follow-up switching valve, 17 follow-up upper pipe, 18 follow-up heat exchanger, 19 follow-up lower pipe, 20 medium hot water take-out pipe, 21 hot water supply Piping, 22 control unit, 22a timer, 23 communication line, 24 remote control, 25 bath return temperature thermistor, 26 bath temperature thermistor, 27 upper tank temperature thermistor, 28 lower tank temperature thermistor, 29 heat pump inlet piping, 30 heat pump outlet piping, 31 Upper piping, 32 bar Pass pipe, 33 hot water outlet pipe, 34 bath circulation pipe, 35 follow fired piping 36 follow fired central pipe, 37 bath solenoid valve, 90 bathtub

Claims (6)

A hot water storage tank for storing hot water,
Bathtub water level detection means for detecting the water level of the bathtub;
Heat exchange means for exchanging heat between bathtub water and hot water in the hot water storage tank;
The water level data of the bathtub by the bathtub water level detection means is stored in association with the time, and based on the water level data, the drain time estimation means for estimating the drain time of the bathtub,
Control means for controlling a bathtub heat recovery operation for recovering heat from the bathtub to the hot water in the hot water storage tank by the heat exchange means;
With
The said control means is the hot water storage type hot water supply machine which controls the said bathtub heat recovery driving | operation based on the remaining time which is the difference of the drainage estimation time estimated by the said drainage time estimation means, and the present time.   2. The hot water storage type hot water supply apparatus according to claim 1, wherein, when the remaining time is smaller than a preset threshold value, the control unit increases the circulation flow rate of the heat exchange unit as compared with a case where the remaining time is not.   The hot water storage type hot water supply apparatus according to claim 1 or 2, wherein the drainage time estimation means estimates the drainage estimation time based on past drainage time data.   The drainage time estimation means determines a bathing end time that is a time when a user has finished bathing, and estimates the drainage estimation time based on data of a time difference between a past draining time and a bathing end time. Or the hot water storage type water heater of Claim 2.   The control means determines whether or not the heat of the bathtub can be recovered after the end of the bathtub heat recovery operation, and determines that the heat of the bathtub can be recovered, the second bathtub heat The hot water storage type hot water supply device according to any one of claims 1 to 4, wherein the recovery operation is performed. A heating means for heating water;
The control means is performing a boiling operation for circulating hot water in the hot water storage tank to the heating means, and when the remaining time is longer than a preset time, the bath heat recovery operation is performed. The hot water storage type hot water supply device according to any one of claims 1 to 5, wherein the start timing is delayed.

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