JP2019090556A - Storage water heater - Google Patents

Abstract

To provide a storage water heater advantageous to making the length of a time of a stirring operation in a bath heat recovery mode appropriate.SOLUTION: A storage water heater 35 includes: a bath heat exchanger 20 for exchanging heat between bath water from a bathtub 30 and tank water from a hot water storage tank 8; and a control device 36 having a bath heat recovery mode of alternately performing a heat exchange operation for simultaneously operating a tank water pump 12 and a bath water pump 29 and a stirring operation for operating the bath water pump 29 without operating the tank water pump 12. When a predetermined time passes after start of the stirring operation, if change amount per hour of a bath water temperature detected by a bath return temperature sensor 38 is smaller than a first reference value, the control device 36 completes the stirring operation.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a hot water storage type hot water supply apparatus.

  DESCRIPTION OF RELATED ART The storage-type hot-water supply apparatus which can perform the bath heat recovery operation | movement which collect | recovers the heat of the bath water which remained in the bathtub after bathing in a hot water storage tank is known. A temperature boundary layer may be formed in the bath as the temperature of the bath decreases and the density increases due to the heat recovery operation returns to the bath. In the conventional hot water storage type hot water supply device disclosed in Patent Document 1 below, a technique is disclosed in which a stirring operation for stirring the inside of a bath to break a temperature boundary layer and a heat recovery operation are repeated.

JP 2001-272106 A

  In the device of Patent Document 1, the heat recovery operation is resumed when the stirring operation is performed for a predetermined time. However, depending on the amount of bath water in the bath or the shape of the bath, the inside of the bath may not be sufficiently stirred by the stirring operation for the predetermined time. Conversely, the inside of the bath may be sufficiently agitated in a time shorter than the predetermined time. Even in such a case, the stirring operation is continued until the predetermined time elapses, so the stirring operation is performed longer than necessary, and power consumption is wasted, and the time required for the entire bath heat recovery operation is long. There is a problem of becoming

  The present invention has been made to solve the problems as described above, and it is an object of the present invention to provide a hot water storage type hot water supply device advantageous for making the time of stirring operation in the bath heat recovery mode an appropriate length. Do.

  According to the present invention, a storage hot water system according to the present invention comprises a heat exchanger for exchanging heat between a hot water storage tank, bath water from a bathtub and tank water from a hot water storage tank, and a tank for circulating tank water to the heat exchanger A first flow path having a water pump, a second flow path having a bath water pump for circulating bath water to a heat exchanger, temperature detection means for detecting a bath water temperature of the second flow path, a tank water pump and a bath Control means having a bath heat recovery mode for alternately performing a heat exchange operation for simultaneously operating the water pump and a stirring operation for operating the bath water pump without operating the tank water pump When a predetermined amount of time has passed from the start of operation and the amount of change per unit time of the bath water temperature detected by the temperature detection means is smaller than the first reference value, the stirring operation is ended. .

  According to the present invention, it is possible to provide a hot water storage type hot water supply device that is advantageous for setting the time of the stirring operation in the bath heat recovery mode to an appropriate length.

FIG. 1 is a diagram showing a hot water storage type hot water supply apparatus according to a first embodiment. It is a circuit block diagram at the time of the bath heat recovery mode in the hot water storage type hot water supply apparatus shown in FIG. FIG. 7 is a diagram showing an example of temporal change in bath return temperature and bath passing temperature in the bath heat recovery mode in the first embodiment. It is a figure which shows the example of the change of the bath return temperature in execution of stirring operation. It is a figure for demonstrating the example of the process in which a control apparatus calculates the variation | change_quantity of bath return temperature in determination of completion | finish of stirring.

  Hereinafter, embodiments will be described with reference to the drawings. The same or corresponding elements in the drawings are denoted by the same reference numerals, and redundant description will be simplified or omitted.

Embodiment 1
FIG. 1 is a diagram showing a hot water storage type hot water supply device 35 according to a first embodiment. As shown in FIG. 1, the hot water storage type hot water supply device 35 according to the first embodiment includes a tank unit 33, an HP (heat pump) unit 7, and a remote control device 44. The HP unit 7 and the tank unit 33 are connected via the HP forward piping 14, the HP return piping 15, and an electrical wiring (not shown). The tank unit 33 incorporates a control device 36. The operations of the various valves, pumps, and the like included in the tank unit 33 and the HP unit 7 are controlled by a controller 36 electrically connected to them.

  The remote control device 44 has a function of receiving an operation of the user regarding a change in the driving operation command and the setting value. The remote control device 44 is an example of a user interface. The control device 36 and the remote control device 44 are connected so as to enable data communication in both directions by wire or wirelessly. Although not shown, the remote control device 44 is equipped with a display unit for displaying information such as the state of the hot water storage type hot water supply device 35, an operation unit such as a switch operated by a user, a speaker, a microphone and the like. The display unit of the remote control device 44 has a function as notification means for notifying the user of the information. The remote control device 44 in the present embodiment includes the display unit as the notification unit, but may alternatively include another notification unit such as a voice guidance device.

  In the present embodiment, the remote control device 44 may be installed on a wall of, for example, a kitchen, a living room, or a bathroom. A plurality of remote control devices 44 may be communicable with the control device 36. Also, for example, a portable terminal such as a smartphone may be configured to have a function as a user interface such as the remote control device 44. The portable terminal and the control device 36 may communicate via a network.

  The HP unit 7 is an example of heating means for heating water. The HP unit 7 includes a refrigerant circuit in which the compressor 1, the water refrigerant heat exchanger 3, the expansion valve 4, and the air heat exchanger 6 are annularly connected by the refrigerant pipe 5. The HP unit 7 operates the heat pump cycle by this refrigerant circuit. In the water-refrigerant heat exchanger 3, the water is heated by exchanging heat between the refrigerant compressed by the compressor 1 and the water led from the tank unit 33. The refrigerant compressed by the compressor 1 and the water directly supplied from a water source such as a water supply may be heat-exchanged by the water refrigerant heat exchanger 3.

  The tank unit 33 incorporates the following various components and piping. The hot water storage tank 8 stores hot and cold water. Inside the hot water storage tank 8, it is possible to form a temperature stratification in which the upper side is a high temperature and the lower side is a low temperature due to the difference in the density of water due to the temperature. The hot water storage tank 8 is not limited to one configured as a single tank as illustrated, but may be one including a plurality of tanks connected in series. In a plurality of hot water storage tanks connected in series, the lower part of the tank on the upper side and the upper part of the next tank that is lower than the tank are sequentially connected via a pipe. In the following description, reference is made to the position in the height direction, ie, the vertical direction, of the hot water storage tank 8, but in the case where the hot water storage tank 8 comprises a plurality of tanks connected in series, In the entire hierarchy up to the tank of, the position in the vertical direction shall be specified.

  A third water supply pipe 9 c is connected to the water inlet 8 a provided at the lower part of the hot water storage tank 8. Water supplied from a water source such as a water supply through the first water supply pipe 9a is adjusted 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. In the upper part of the hot water storage tank 8, a hot water introduction outlet 8d for supplying the hot water stored in the hot water storage tank 8 to the outside of the hot water storage type hot water supply apparatus 35 and a hot water introduction outlet 8e which can communicate with the HP return piping 15 It is provided. A plurality of hot water storage temperature sensors 41, 42, 43 are attached to the surface of the hot water storage tank 8 at different heights. The hot water storage temperature sensor 41 is located at the same height as the middle warm water introduction outlet 8 f or at a height close to the middle warm water introduction outlet 8 f. The hot water storage temperature sensor 42 is located higher than the hot water storage temperature sensor 41. The hot water storage temperature sensor 43 is at a lower position than the hot water storage temperature sensor 41. By detecting the temperature distribution of the hot and cold water in the hot water storage tank 8 by the hot water storage temperature sensors 41, 42 and 43, it is possible to grasp the remaining hot water amount or the heat storage amount in the hot water storage tank 8.

  The control device 36 controls a hot water storage operation in which the hot water heated by the HP unit 7 flows into the hot water storage tank 8. Control device 36 controls start, stop, etc. of the hot water storage operation according to the amount of stored hot water or the amount of heat storage in hot water storage tank 8. In hot water storage operation, it becomes as follows. The low temperature water flowing out from the lower part of the hot water storage tank 8 is led to the HP unit 7 via the HP forward piping 14 and heated in the water refrigerant heat exchanger 3 to become hot water, that is, high temperature water. This high temperature water flows into the hot water storage tank 8 from the hot water introduction outlet 8 e at the upper part of the hot water storage tank 8 via the HP return pipe 15. By performing such a hot water storage operation, high temperature water is stored from the upper layer portion inside the hot water storage tank 8, and the high temperature water layer gradually becomes thick. The control device 36 ends the hot water storage operation when the amount of stored hot water or the amount of stored heat in the hot water storage tank 8 grasped by the hot water storage temperature sensors 41, 42, 43 exceeds a predetermined amount.

  The tank unit 33 incorporates the tank water pump 12 and the bath heat exchanger 20. The tank water pump 12 is a pump for circulating hot and cold water through various pipes, and is provided on the first water supply pipe 13a. The bath heat exchanger 20 exchanges heat between the tank water supplied from the hot water storage tank 8 and the bath water from the bath 30.

  The forward-bath pipe 27 and the return-bath pipe 28 are connected to a bathtub adapter 80 installed in the bathtub 30. The bath heat exchanger 20 is installed in the middle of the bath forward pipe 27 and the bath return pipe 28. A bath temperature sensor 37 for detecting the temperature of the bath water having passed through the bath heat exchanger 20 is installed in the middle of the bath piping 27. In the middle of the bath return pipe 28, a bath water pump 29 for circulating bath water, and a bath return temperature sensor for detecting the temperature of the bath water before entering the bath heat exchanger 20 from the bath 30 A water level sensor 46 for detecting a water level level in the bathtub 30, and a flow switch 47 for detecting water circulation in the bath return pipe 28 are provided. In the following description, the temperature detected by the bath return temperature sensor 38 is referred to as a “bath return temperature”. Further, the temperature detected by the on-the-bath temperature sensor 37 is referred to as a "on-the-bath temperature".

  The three-way valve 11 is a flow path switching unit having an a port and a b port as inlets and a c port as an outlet. The three-way valve 11 is configured to be able to switch the flow path between two paths ac and bc.

  The four-way valve 16 is a flow path switching unit having an a port and a b port as inlets, and a c port and d port as outlets. The four-way valve 16 is configured to be able to switch the flow path among four paths of ac, ad, bc, and bd.

  The four-way valve 18 is a flow path switching unit having an a port serving as an inlet and a b port serving as an outlet, a c port, and a d port. The four-way valve 18 is configured to be able to switch the flow path among the three paths ab, ac, and ad.

  The tank unit 33 has a low temperature pipe 10, a first water supply pipe 13a, a first hot water pipe 17a, a second hot water pipe 17b, a third hot water pipe 19a, a fourth hot water pipe 19b, and a fifth hot water pipe 19c. . The low temperature piping 10 connects the water outlet 8 b provided at the lower part of the hot water storage tank 8 and the a port of the three-way valve 11. The first water supply pipe 13 a connects the c port of the three-way valve 11 and the inlet of the tank water pump 12. The HP forward piping 14 connects the outlet of the tank water pump 12 and the inlet of the HP unit 7. The HP return pipe 15 connects the outlet of the HP unit 7 and the b port of the four-way valve 16. The first hot water pipe 17 a connects the d port of the four-way valve 16 and the a port of the four-way valve 18. The second hot water pipe 17 b connects the c port of the four-way valve 16 and the water inlet 8 c provided in the lower part of the hot water storage tank 8. The third hot water pipe 19 a connects the b port of the four-way valve 18 and the hot water introduction outlet 8 e above the hot water storage tank 8. The fourth hot water pipe 19 b connects the d port of the four-way valve 18 and the hot water introduction outlet 8 d provided in the upper part of the hot water storage tank 8. The fifth hot water pipe 19 c connects the c port of the four-way valve 18 and the hot water inlet 8 g provided between the upper part of the hot water storage tank 8 and the middle part.

  The first tank circulation pipe 20 a connects the b port of the four-way valve 18 to the inlet of tank water of the bath heat exchanger 20. The second tank circulation pipe 20 c connects the tank water outlet of the bath heat exchanger 20 and the b port of the three-way valve 11. The second water supply pipe 13 b branches from between the tank water pump 12 and the inlet of the HP unit 7 in the HP forward pipe 14, and is connected to the a port of the four-way valve 16.

  Furthermore, the tank unit 33 includes the medium temperature piping 79, the first water supply piping 9a, the second water supply piping 9b, the third water supply piping 9c, the fourth water supply piping 9d, the hot water supply mixing valve 22, the bath mixing valve 23, the middle warm water switching The valve 78, the hot water supply pipe 24, the bath pipe 25, the return pipe 20b, and the check valve 50 are provided.

  The middle warm water switching valve 78 is a flow path switching unit having an a port and a b port as an inlet and a c port as an outlet. The middle warm water switching valve 78 is configured to be able to switch the flow path between the two paths ac and bc.

  The hot water supply mixing valve 22 is mixing means provided with a first inlet, a second inlet, and an outlet. The bath mixing valve 23 is mixing means provided with a first inlet, a second inlet, and an outlet.

  One end of the first water supply pipe 9a is connected to a water source such as a water supply. The second water supply pipe 9 b and the third water supply pipe 9 c are connected to the other end of the first water supply pipe 9 a via the pressure reducing valve 31. The second water supply pipe 9 b is connected to the a port of the middle warm water switching valve 78. The middle temperature pipe 79 connects the middle warm water inlet / outlet 8 f provided in the middle portion of the hot water storage tank 8 and the b port of the middle warm water switching valve 78. The return pipe 20 b branches from the middle of the second tank circulation pipe 20 c and is connected to the middle temperature pipe 79. The check valve 50 is disposed on the return pipe 20b. The check valve 50 inhibits the flow from the middle portion of the hot water storage tank 8 toward the lower portion of the hot water storage tank 8. Thereby, the outflow of the heat from the middle part of the hot water storage tank 8 to the lower part of the hot water storage tank 8 can be reliably prevented. One end of the fourth water supply pipe 9 d is connected to the c port of the middle warm water switching valve 78. The other end of the fourth water supply pipe 9 d is connected to the first inlets of the hot water supply mixing valve 22 and the bath mixing valve 23. One end of the high temperature pipe 21 communicates with the hot water introduction outlet 8 d of the hot water storage tank 8. The other end of the high temperature pipe 21 is connected to the second inlets of the hot water supply mixing valve 22 and the bath mixing valve 23.

  The middle warm water switching valve 78 has two flows, a first flow path state in which the second water supply pipe 9b and the fourth water supply pipe 9d communicate with each other, and a second flow state in which the intermediate temperature pipe 79 and the fourth water supply pipe 9d communicate with each other. Switch and use the road condition. When the middle warm water switching valve 78 is in the first flow path state, low temperature water supplied from the water source is supplied to the hot water supply mixing valve 22 and the bath mixing valve 23 through the second water supply pipe 9b and the fourth water supply pipe 9d. It will be in the state of being The first flow passage state of the middle warm water switching valve 78 corresponds to the “low temperature water use state”. When the middle warm water switching valve 78 is set to the second flow path state, middle warm water supplied from the hot water storage tank 8 through the middle temperature piping 79 passes through the fourth water supply piping 9 d, and the hot water supply mixing valve 22 and the bath mixing valve It is in the state of being supplied to 23. The second flow passage state of the middle warm water switching valve 78 corresponds to the “middle warm water use state”.

  The hot water supply mixing valve 22 allows the user to adjust the flow ratio of the high temperature water supplied from the hot water storage tank 8 through the high temperature pipe 21 to the low temperature water or middle warm water supplied from the fourth water supply pipe 9 d. Hot water of the set temperature set by the remote control device 44 is generated, and flows into the hot water supply pipe 24. Hot water whose temperature is adjusted by the hot water supply mixing valve 22 is supplied from a hot water supply pipe 24 to a faucet (not shown) such as a shower, a callan, etc., which is used by a user via the hot water supply plug 34.

  The mixing valve 23 for the bath adjusts the flow ratio of the high temperature water supplied from the hot water storage tank 8 through the high temperature pipe 21 to the low temperature water or middle warm water supplied from the fourth water supply pipe 9 d. The hot water of the set temperature set by the remote control device 44 can be generated. The hot water adjusted to the set temperature by the bath mixing valve 23 flows into the bathtub 30 through the bath flow sensor 45, the bath solenoid valve 26, the bath forward pipe 27 and the bath return pipe 28 by the bath pipe 25.

  The control device 36 determines the completion of the pouring based on the information detected by the flow rate sensor 45 for bath and the water level sensor 46, thereby determining the amount of pouring water which is the amount of bath water in the bath 30 at the completion of filling. However, the amount of hot water set by the user with the remote control device 44 can be controlled to be equal. The hot water storage type hot water supply device 35 of the present embodiment may be one capable of performing automatic bath operation. When the automatic bath operation is set by remote control device 44, control device 36 maintains the temperature and the amount of the bath water in bathtub 30 at the temperature and the amount set by remote control device 44 after the completion of the filling. If necessary, raise the temperature of the bath water, cool it, add hot water and boiling water.

  Control device 36 in the present embodiment has a bath heat recovery mode as a control mode. The bath heat recovery mode is a mode for recovering the heat of the bath water remaining in the bath 30 into the hot water storage tank 8 after bathing. FIG. 2: is a circuit block diagram at the time of bath heat collection | recovery mode in the hot water storage type hot-water supply apparatus 35 shown in FIG. In the bath heat recovery mode, it is as follows. The three-way valve 11 is controlled such that the port a and the port c communicate with each other and the port b is closed. As a result, the low temperature piping 10 and the first water supply piping 13a communicate with each other, and the flow path to the second tank circulation piping 20c is blocked. The four-way valve 16 is controlled such that the a port and the d port communicate with each other, and the b port and the c port are in a closed state. Thereby, while the 2nd water supply piping 13b and the 1st warm water piping 17a connect, the 2nd warm water piping 17b side is closed, and the channel to the lower part of hot water storage tank 8 is intercepted. The four-way valve 18 is controlled such that the a port and the b port communicate with each other, and the c port and the d port are in a closed state. Thereby, while connecting the 1st warm water piping 17a and the 3rd warm water piping 19a, the 4th warm water piping 19b and the 5th warm water piping 19c side are closed, and the channel to the middle part of hot water storage tank 8 is intercepted.

  When the bath heat recovery mode is started, first, the circulation of the bath water is started by the bath water pump 29 starting operation, and the three-way valve 11, the four-way valve 16, and the four-way valve 18 are controlled as described above. In this state, the operation of the tank water pump 12 is started. Tank water circulates as follows. The low temperature tank water which flowed out from the water outlet 8b of the hot water storage tank 8 through the low temperature piping 10 is the three-way valve 11, the first water supply piping 13a, the tank water pump 12, the second water supply piping 13b, the four way valve 16, the first It flows into the bath heat exchanger 20 through the hot water pipe 17a, the four-way valve 18, the third hot water pipe 19a, and the first tank circulation pipe 20a. In the bath heat exchanger 20, the tank water is heated by the heat of the bath water from the bath 30, and reaches a temperature close to the temperature of the bath water in the bath 30. The heated tank water may be hereinafter referred to as "heat recovery warm water". The heat recovery hot water flows from the bath heat exchanger 20 through the return pipe 20b, the check valve 50, and the medium temperature pipe 79 into the hot water storage tank 8 from the middle warm water introduction outlet 8f. In the present embodiment, the above-described tank water flow path corresponds to the “first flow path”. When the bath heat recovery mode is implemented, heat recovery hot water is stored near the middle warm water introduction outlet 8 f in the hot water storage tank 8.

  When the bath water pump 29 is operated, the bath water in the bath 30 is drawn from the bath adapter 80 to the bath return pipe 28 and flows into the bath heat exchanger 20 through the bath return pipe 28. The bath water having passed through the bath heat exchanger 20 passes through the bath forward pipe 27 and flows into the bath 30 from the bath adapter 80. In the present embodiment, the flow path of the bath water described above corresponds to the “second flow path”. Further, the bath return temperature sensor 38 corresponds to “a temperature detection unit that detects the temperature of the bath water in the second flow path”.

  In the present embodiment, the control device 36 alternately performs the heat exchange operation and the stirring operation in the bath heat recovery mode. The heat exchange operation is an operation of transferring the heat of the bath water in the bath 30 into the hot water storage tank 8 by operating the tank water pump 12 and the bath water pump 29 simultaneously. The stirring operation is an operation of stirring the bath water in the bath 30 by operating the bath water pump 29 without operating the tank water pump 12.

  Hereinafter, the flow rate of the bath water flowing through the bath forward pipe 27 and the bath return pipe 28 will be referred to as "bath water flow rate". The controller 36 can adjust the rotational speed of the water pump 29. The higher the rotational speed of the bath water pump 29, the higher the flow rate of the bath water. It is desirable that the controller 36 control the water pump 29 so that the rotation speed of the water pump 29 in the stirring operation is higher than the rotation speed of the water pump 29 in the heat exchange operation. Thereby, the following effects can be obtained. In the stirring operation, the flow velocity of the bath water flowing into the bathtub 30 from the forward bath piping 27 becomes high, so the inside of the bathtub 30 can be stirred more efficiently. In the heat exchange operation, the power consumption of the water pump 29 can be reduced because the flow rate of the water is relatively low. Moreover, since the time from the bath water to entering and leaving the bath heat exchanger 20 becomes longer, more heat of the bath water can be transferred to the tank water.

  Control device 36 may start the bath heat recovery mode in response to a user operation on remote control device 44. For example, when a predetermined button of remote control device 44 is pressed, control device 36 may start the bath heat recovery mode.

  If the temperature of the tank water at the lower part of the hot water storage tank 8 detected by the hot water storage temperature sensor 43 is lower than the bath return temperature detected by the bath return temperature sensor 38, bath heat recovery is possible. For this reason, the control device 36 may permit the start of the bath heat recovery mode when the temperature detected by the hot water storage temperature sensor 43 is lower than the bath return temperature.

  When the heat exchange operation is performed, a temperature boundary layer is generated in the bath water in the bath 30. In the heat exchange operation, the bath water flowing out of the bath heat exchanger 20 is deprived of heat by the tank water, and its temperature is lowered to increase its density. When this bath water flows into the bath 30, the relatively hot bath water of low density stays above the inside of the bath 30, and the relatively cold bath water of high density stays below the inside of the bath 30. In the bath 30, a temperature boundary layer having a high temperature on the upper side and a low temperature on the lower side is generated. If the temperature boundary layer is at a position higher than the position of the bath adapter 80, the high temperature bath water on the upper side can not be drawn into the bath return pipe 28, so the temperature of the bath water flowing into the bath heat exchanger 20 is low. Heat recovery efficiency is reduced.

  On the other hand, when the stirring operation is performed from the state where the temperature boundary layer is formed in the bath 30, the temperature boundary layer in the bath 30 is broken, and the relatively high temperature upper layer bath water and the relatively low temperature lower layer side Mix with the bath water. As a result, since the temperature of the bath water at the height of the bath adapter 80 rises, the temperature of the bath water flowing into the bath heat exchanger 20 rises. Therefore, the heat recovery efficiency is improved by performing the heat exchange operation after the stirring operation.

  In the present embodiment, the following effects can be obtained by stopping the tank water pump 12 during the stirring operation. Since the bath water is not cooled in the bath heat exchanger 20, it is possible to prevent the temperature of the jet flowing from the bath return pipe 27 into the bath 30 from being lowered. Therefore, the time required for the temperature of the entire bath water in the bath 30 to be uniformed can be shortened, so that the time required for the stirring operation can be shortened. As a result, since the time required for the entire bath heat recovery mode can be shortened, the usability for the user is improved. Furthermore, the power consumption of the tank water pump 12 can also be saved.

  The rotational speed of the bath water pump 29 in the stirring operation is controlled to be equal to or higher than a predetermined rotational speed at which the bath water in the bath 30 can be stirred. For example, if the flow rate of the bath water at the time of stirring operation is 8 L / min, the bath water in the bath 30 can be sufficiently stirred. Therefore, the control device 36 may control the rotational speed of the water pump 29 so that the flow rate of the water during the stirring operation is 8 L / min or 8 L / min or more. On the other hand, for example, at a flow rate of 3 L / min or less, it may be difficult to efficiently stir the bath water in the bath 30.

  FIG. 3 is a diagram showing an example of temporal change in bath return temperature and bath passing temperature in the bath heat recovery mode according to the first embodiment. The example shown in FIG. 3 is as follows. The bath heat recovery mode is started at time t0. When the bath heat recovery mode is started, a heat exchange operation is performed first. This first heat exchange operation is continued from time t0 to time t1. At time t1, the first heat exchange operation is finished, and the operation shifts to the first stirring operation. The first stirring operation is continued from time t1 to time t2. At time t2, the first stirring operation is finished, and the process shifts to the second heat exchange operation. The second heat exchange operation is continued from time t2 to time t3. At time t3, the second heat exchange operation is ended, and the operation shifts to the second stirring operation. The second stirring operation is continued from time t3 to time t4. At time t4, the second stirring operation is ended, and the execution of the bath heat recovery mode is ended without shifting to the third heat exchange operation.

  As shown in FIG. 3, while the heat exchange operation is being performed, the bath return temperature and the bath passing temperature decrease with the passage of time. This is because the bath water cooled by heat exchange with the tank water in the bath heat exchanger 20 flows into the bath 30 from the forward bath pipe 27 so that the temperature of the bath water in the bath 30 gradually decreases. In order to When the heat exchange operation is performed, the above-described temperature boundary layer is generated in the bath 30. Thereafter, while the stirring operation is being performed, the bath return temperature and the bath passing temperature rise with the passage of time. This is because the temperature boundary layer in the bathtub 30 is broken by the stirring operation, and the relatively high temperature upper side bath water and the relatively low temperature lower side bath water are mixed, so that the bath is returned from the bath adapter 80 This is because the temperature of the bath water drawn into the pipe 28 rises.

  During the heat exchange operation, if the bath return temperature and the bath return temperature decrease with the passage of time, the temperature difference between the bath water and the tank water in the bath heat exchanger 20 is reduced. , The amount of heat exchange is reduced. As a result, since the difference between the temperature of the bath water leaving the bath 30 and the temperature of the bath water returning to the bath 30 becomes smaller, the amount of change per hour of the bath return temperature and the bath trip temperature becomes smaller. The positions shown by the arrows A and C in FIG. 3 correspond to the case where the change per unit time of the bath return temperature and the bath return temperature becomes small.

  The bath return temperature during execution of the stirring operation usually rises with the passage of time. The rate of rise of the bath return temperature in that case decreases with the passage of time. This is because the temperature of the bath water in the bath 30 approaches a uniform state. The position indicated by the arrow B in FIG. 3 corresponds to the case where the rate of rise of the bath return temperature is lowered.

  When a predetermined time has elapsed from the start of the stirring operation, control device 36 determines that the amount of change per unit time of the bath return temperature detected by bath return temperature sensor 38 is smaller than the first reference value. The stirring operation is ended. In the following description, this "predetermined time" is referred to as "standard stirring time". The decrease in the amount of change per hour of the bath return temperature in the stirring operation is considered to mean that the temperature of the bath water in the bath 30 has become uniform. In the present embodiment, the stirring operation is ended when the amount of change per hour of the bath return temperature becomes smaller than the first reference value, and the time for the stirring operation is appropriately shifted to the heat exchange operation. The length can be That is, it is possible to prevent the stirring operation from being completed before the stirring operation time is sufficiently short and the inside of the bath 30 is sufficiently stirred, and conversely, the time for continuing the stirring operation to be unnecessarily long . As a result, the power consumption of the water pump 29 can be saved while improving the heat recovery efficiency. Moreover, the required time of the whole bath heat recovery mode can be shortened as much as possible, and it can suppress that heat is dissipated from the bathtub 30 during stirring operation. Further, according to the present embodiment, since the stirring operation is ended based on the amount of change in the bath return temperature per time, it is not necessary to be influenced by the temporary fluctuation of the bath return temperature due to the disturbance. Therefore, it is possible to more reliably prevent the termination of the stirring operation at an inappropriate timing.

  In the following description, a process in which the control device 36 determines based on the bath return temperature whether or not to end the stirring operation is referred to as “stirring end determination”. The standard stirring time may be preset as a standard time required for the temperature in the bath 30 to become uniform by the stirring operation from the state where the temperature boundary layer is formed in the bath 30. For example, when the stirring operation is performed at a bath water flow rate of 8 L / min, the standard stirring time may be 5 minutes. Note that “the temperature in the bath 30 is uniform” may be, for example, that the difference between the water temperature at the bottom and the water temperature at the water surface in the bath 30 is 2 ° C. or less.

  In the present embodiment, when the standard stirring time has elapsed from the start of the stirring operation, the control device 36 determines the stirring end to prevent the time of the stirring operation from becoming too short.

  Further, according to the present embodiment, since the stirring completion determination is performed based on the bath return temperature instead of the bath going temperature, there is no influence of heat transfer from the bath heat exchanger 20. For this reason, it is possible to more accurately determine whether or not the inside of the bath 30 is sufficiently agitated.

  In the example of FIG. 3, the time from time t1 to time t2 corresponds to the standard stirring time, and as a result of the controller 36 performing the stirring end determination at time t2, the first stirring operation ends at time t2. .

  When ending the stirring operation and shifting to the heat exchange operation, the following may be performed. The control device 36 terminates the stirring operation by temporarily stopping the bath water pump 29, and resumes the operation of the tank water pump 12 which has been stopped. After the operation of the tank water pump 12 starts, the operation of the bath water pump 29 is restarted to shift to the heat exchange operation. Alternatively, the control device 36 may shift from the stirring operation to the heat exchange operation without temporarily stopping the water pump 29.

  FIG. 4 is a diagram showing an example of a change in bath return temperature during execution of the stirring operation. When a change in the bath return temperature indicated by the solid line in FIG. 4 is detected, the control device 36 shifts to the heat exchange operation again after the end of the stirring operation, and continues the bath heat recovery mode. On the other hand, when a change in the bath return temperature indicated by the broken line in FIG. 4 is detected, the control device 36 performs the bath heat recovery mode without shifting to the heat exchange operation again after the stirring operation ends. finish. As described above, the control device 36 determines that the temperature difference between the bath return temperature at the start of the stirring operation and the bath return temperature at the end of the stirring operation is within a predetermined reference value (for example, within 0.25 ° C.) At this time, the bath heat recovery mode may be ended without shifting to the heat exchange operation again. As a result, the bath heat recovery mode can be promptly ended when no recoverable heat amount remains in the bath 30, so that the required time for the entire bath heat recovery mode can be shortened, and the bath water pump 29 can be reduced. And the power consumption of the tank water pump 12 can be reduced.

  In the stirring completion determination, for example, the control device 36 may compare the amount of change in the bath return temperature in 15 seconds with a first reference value (for example, 0.25 ° C.). The amount of change in the bath return temperature in the determination of completion of stirring may be very small. For example, the change amount of the bath return temperature for 15 seconds may be about 0.25 ° C. to 0.5 ° C. in the stirring completion determination. The control device 36 may perform the following calculation in order to perform the stirring completion determination with high accuracy based on such a minute amount of change in bath return temperature.

  FIG. 5 is a diagram for explaining an example of processing in which the control device 36 calculates the change amount of the bath return temperature in the stirring completion determination. The example of the sampling data shown in the upper stage in FIG. 5 corresponds to temperature data acquired by the control device 36 from the bath return temperature sensor 38 every 100 milliseconds, for example. The control device 36 uses 30 of the sampling data, and calculates the average value of the bath return temperature in 3 seconds by calculating their arithmetic average value. The averaged temperature data is considered as a representative value of the bath return temperature in the 3 seconds. The averaged data shown in the lower part of FIG. 5 corresponds to the representative value of the bath return temperature every 3 seconds calculated as described above. For example, when calculating the amount of change in bath return temperature in 15 seconds, the controller 36 uses five representative values of the bath return temperature every 3 seconds, and the difference between the maximum value and the minimum value among them is 15 It is regarded as a change in bath return temperature in seconds and compared with the first reference value. By doing as described above, the accuracy of the stirring completion determination is further improved.

  When the standard stirring time has elapsed from the start of the stirring operation, the control device 36 sets the change amount per hour of the bath return temperature to a second reference value (eg, 0.1 ° C.) smaller than the first reference value. If it is smaller than this, execution of the bath heat recovery mode may be ended without shifting to the heat exchange operation. As a result, the bath heat recovery mode can be promptly ended when no recoverable heat amount remains in the bath 30, so that the required time for the entire bath heat recovery mode can be shortened, and the bath water pump 29 can be reduced. And the power consumption of the tank water pump 12 can be reduced.

  Hereinafter, the amount of bath water in the bath 30 will be referred to as "bath water amount". When the amount of bathing water is relatively large, the time required to make the temperature of the bath water in the bath 30 uniform by the stirring operation tends to be longer than when the amount of bathing water is relatively small. In view of such characteristics, the control device 36 sets the standard stirring time according to the amount of bathing water so that the standard stirring time when the amount of bathing water is relatively small is shorter than the standard stirring time when the amount of bathing water is relatively large. The stirring time may be set. By doing so, the time of stirring operation can be controlled more appropriately according to the amount of bath water. In the above control, the control device 36 may control the value of the amount of hot water set by the user with the remote control device 44 as the amount of bathtub water, or may control the amount of bathtub water by the water level detected by the water level sensor 46 It may be calculated. In addition, the control device 36 may change the standard stirring time into a plurality of steps or continuously change the standard stirring time according to the amount of bath water.

  The first predetermined time is a time shorter than the standard stirring time. In the example of FIG. 3, the time from time t3 to time t4 corresponds to the first predetermined time. The first predetermined time may be, for example, 90 seconds. The control device 36 shifts to the heat exchange operation when the amount of change per hour of the bath return temperature is smaller than the third reference value when the first predetermined time has elapsed from the start of the stirring operation. Alternatively, the execution of the bath heat recovery mode may be ended. The third reference value is a value smaller than the first reference value. The third reference value may be, for example, 0.5 ° C. In the example of FIG. 3, since the amount of change per time of the bath return temperature is smaller than the third reference value at time t4, the execution of the bath heat recovery mode ends at time t4. According to the above, since the bath heat recovery mode can be promptly ended when no recoverable heat amount remains in the bath 30, the time required for the entire bath heat recovery mode can be shortened. The power consumption of the bath water pump 29 and the tank water pump 12 can be reduced.

  The second predetermined time is a time shorter than the standard stirring time. The second predetermined time may be shorter than the first predetermined time. The second predetermined time may be, for example, 45 seconds. The controller 36 continues the stirring operation even after the first predetermined time has elapsed from the start of the stirring operation, and within each second predetermined time, the second predetermined time has elapsed. The change amount of the bath return temperature may be compared with the fourth reference value, and the stirring operation may be ended if the change amount is smaller than the fourth reference value. The fourth reference value may be, for example, 0.25.degree. In the example of FIG. 3, since the stirring operation is continued even after the first predetermined time has elapsed from the start of the first stirring operation from time t1, the control device 36 passes the second predetermined time. Every time, the variation of the bath return temperature within the second predetermined time is compared with the fourth reference value. In this example, the stirring operation is continued because the amount of change in the bath return temperature within the second predetermined time is not smaller than the fourth reference value.

  Depending on the temperature distribution in the bath 30 before the stirring operation or the shape of the bath 30, the temperature in the bath 30 may be equalized by the stirring operation for a time shorter than the standard stirring time. In such a case, as described above, the change amount of the bath return temperature within the second predetermined time after the first predetermined time has elapsed, and as a fourth criterion When the amount of change is smaller than the fourth reference value in comparison with the value, the stirring operation can be ended without waiting for the standard stirring time to elapse by ending the stirring operation. Therefore, the time required for the entire bath heat recovery mode can be shortened, and the power consumption of the bath water pump 29 and the tank water pump 12 can be reduced.

  The third predetermined time is a time shorter than the standard stirring time. The third predetermined time may be longer than the first predetermined time. The third predetermined time may be, for example, 130 seconds. The control device 36 may not determine whether to end the stirring operation until the third predetermined time elapses from the start of the first stirring operation. Before the first stirring operation, it is highly likely that the temperature boundary layer in the bath 30 has been generated. For this reason, the stirring operation is reliably continued until at least the third predetermined time elapses from the start of the first stirring operation by doing as described above, so the stirring in the bath 30 is insufficient. Can be prevented more reliably.

  When the control device 36 detects that the bath water in the bath 30 starts to be discharged from the drain plug provided at the bottom of the bath 30, it is desirable to finish the execution of the bath heat recovery mode. This makes it possible to reliably prevent the inflow of air to the bath water pump 29 and also to reliably prevent the inflow of air to the bath return pipe 28, thereby more reliably preventing an erroneous determination in the stirring completion determination. It becomes possible. The control device 36 can detect that the bath water in the bathtub 30 has started to be drained from the drain plug, for example, by detecting the lowering of the water level in the bathtub 30 by the water level sensor 46. Also, when the bathtub 30 is provided with an automatic drain valve that can be automatically opened and closed, the control device 36 receives a signal indicating that the automatic drain valve has opened, from the device that controls the automatic drain valve. The controller 36 can detect that the bath water in the bath 30 has begun to be drained from the drain valve.

  When the hot water supply to the bath tub 30 is started, the control device 36 preferably terminates the execution of the bath heat recovery mode. If a user inputs a hot water supply instruction to the bathtub 30 to the remote control device 44, that is, if an instruction such as filling with water or pouring water is input, the bathtub 30 may be used again for bathing. It is believed that there is. Therefore, when hot water supply to the bathtub 30 is started, the convenience of the user who baths can be improved by ending execution of bath heat recovery mode.

  The control device 36 may end the stirring operation when the time during which the stirring operation is continued exceeds the predetermined upper limit of stirring time. The upper limit of stirring time is longer than the standard stirring time. By doing so, it is possible to more reliably prevent the stirring operation time from becoming too long. In addition, the control device 36 may lengthen the stirring upper limit time when the bathing water amount is relatively large compared to when the bathing water amount is relatively small.

1 compressor, 3 water refrigerant heat exchanger, 4 expansion valve, 5 refrigerant piping, 6 air heat exchanger, 7 HP unit, 8 hot water storage tank, 8a water inlet, 8b water outlet, 8c water inlet, 8d, 8e hot water inlet / outlet, 8f middle warm water inlet / outlet, 8g hot water inlet, 9a first water supply piping, 9b second water supply piping, 9c third water supply piping, 9d fourth water supply piping, 10 low temperature piping, 11 three-way valve, 12 tanks Water pump, 13a first water pipe, 13b second water pipe, 16 four-way valve, 17a first hot water pipe, 17b second hot water pipe, 18 four-way valve, 19a third hot water pipe, 19b fourth hot water pipe, 19c fifth water pipe Hot water piping, 20 bath heat exchangers, 20a first tank circulation piping, 20b return piping, 20c second tank circulation piping, 21 high temperature Pipe, 22 mixing valve for hot water supply, 23 mixing valve for bath, 24 hot water supply piping, 25 bath piping, 26 solenoid valve for bath, 29 bath water pump, 30 bath, 31 pressure reducing valve, 33 tank unit, 34 hot water tap, 35 hot water storage Water heater, 36 controllers, 37 bath temperature sensors, 38 bath return temperature sensors, 41, 42, 43 hot water storage temperature sensors, 44 remote control devices, 45 bath flow sensors, 46 water level sensors, 47 flow switches, 48 temperature sensors , 50 check valve, 78 medium temperature switching valve, 79 medium temperature piping, 80 bathtub adapter

Claims (9)

With a hot water storage tank,
A heat exchanger for exchanging heat between bath water from a bath and tank water from the hot water storage tank;
A first flow path having a tank water pump for circulating the tank water to the heat exchanger;
A second flow path having a bath water pump for circulating the bath water to the heat exchanger;
Temperature detection means for detecting the temperature of the bath water in the second flow path;
Control means having a bath heat recovery mode for alternately performing a heat exchange operation for simultaneously operating the tank water pump and the bath water pump, and a stirring operation for operating the bath water pump without operating the tank water pump ,
Equipped with
The control means, when a predetermined time has elapsed since the start of the stirring operation, the amount of change per hour of the bath water temperature detected by the temperature detection means is smaller than the first reference value. A hot water storage type hot water supply device that completes the stirring operation.   When the predetermined time has elapsed from the start of the stirring operation, the control means is configured to change the amount of change per hour of the bath water temperature smaller than a second reference value smaller than the first reference value. The hot water storage type hot water supply apparatus according to claim 1, wherein the execution of the bath heat recovery mode is ended without shifting to the heat exchange operation.   The hot water storage type hot water supply system according to claim 1 or 2, wherein the control means terminates the execution of the bath heat recovery mode when detecting that the bath water in the bath has started to be discharged from the drain plug of the bath. apparatus.   The hot water storage type hot water supply apparatus according to any one of claims 1 to 3, wherein the control means ends the execution of the bath heat recovery mode when the hot water supply to the bathtub is started.   The control means may be configured such that, when a first predetermined time shorter than the predetermined time has elapsed since the start of the stirring operation, the amount of change per hour of the bath water temperature is smaller than the first reference value. The storage hot water system hot-water supply device according to any one of claims 1 to 4 which ends execution of said bath heat recovery mode, without shifting to said heat exchange operation, when smaller than a reference value.   The control means is configured to continue the stirring operation even after the first predetermined time has elapsed from the start of the stirring operation, every time a second predetermined time shorter than the predetermined time has elapsed. The amount of change in the temperature of the bath water within the second predetermined time is compared with a fourth reference value, and when the amount of change is smaller than the fourth reference value, the stirring operation is ended. The hot water storage type hot water supply apparatus according to 5.   The predetermined time when the amount of bath water in the bath is relatively large is set to be longer than the predetermined time when the amount of bath water in the bath is relatively small. The hot water storage type hot water supply apparatus according to any one of claims 6 to 7.   The control means does not determine whether or not to end the stirring operation during a period until a third predetermined time elapses from the start of the first stirring operation. The hot water storage type hot water supply device described in.   The hot water storage type hot water supply device according to any one of claims 1 to 8, wherein the temperature detection means detects a temperature of the bath water before entering the heat exchanger.

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