JP6628642B2 - Hot water supply system - Google Patents

Description

  The present invention relates to a hybrid hot water supply system including, as heating sources, a heat pump for boiling water in a hot water storage tank and an instantaneous heating type auxiliary heat source device.

  BACKGROUND ART Conventionally, a so-called hybrid hot water supply system including a heat pump that heats hot water in a hot water storage tank and an instantaneous heating type auxiliary heat source device that heats hot water flowing through a tapping pipe connected to the hot water storage tank is known. (For example, see Patent Document 1).

  In the hot water supply system described in Patent Literature 1, the first hot water on the day when the water in the hot water storage tank is to be boiled based on the past hot water usage on a daily (0:00 to 24:00) basis. The time when the supply of water is started (hot water supply start time), the time when hot water filling into the bathtub is started (hot water filling start time), and the time when the last hot water supply ends (hot water supply end time) are assumed. .

  Then, the heating of the water in the hot water storage tank by the heat pump is started so that the boiling of the water in the hot water storage tank ends at the hot water supply start time and the hot water filling start time assumed in this way, and the water supply end time is shorter than the hot water supply end time. After the time before the predetermined time, the heat pump is stopped.

JP 2013-224762 A

  According to the hot water supply system described in Patent Literature 1, it is expected that the water in the hot water storage tank can be heated at an appropriate timing to supply hot water by a relatively simple control method based on past hot water usage. In a hybrid hot water supply system, it is desired that hot water supply with lower running cost be performed by a combination of a heat pump and an auxiliary heat source device.

  The present invention has been made in view of such a background, and an object of the present invention is to provide a hot water supply system capable of supplying hot water with lower running cost by a combination of a heat pump and an auxiliary heat source device.

The hot water supply system of the present invention
A hot water storage tank in which a water supply pipe is connected to a lower part and a tapping pipe is connected to an upper part, and water supplied from the water supply pipe is stored,
A tank circulation path connecting the lower part and the upper part of the hot water storage tank,
A tank circulation pump that circulates hot water stored in a lower portion of the hot water storage tank to an upper portion of the hot water storage tank through the tank circulation path,
A heat pump that heats hot water flowing through the tank circulation path,
A hot water storage amount recognition unit that recognizes the amount of hot water stored in the hot water storage tank,
A water amount sensor that detects the flow of hot water from the hot water storage tank to the tapping pipe;
A tapping temperature sensor for detecting the temperature of tap water supplied from the tapping pipe,
An instantaneous heating type auxiliary heat source device for heating hot water flowing through the tapping pipe,
A filling pipe branched from the tapping pipe downstream of the heating point by the auxiliary heat source unit and communicated with the bathtub,
A filling valve for opening and closing the filling pipe,
A filling control unit that executes a filling operation in which the filling valve is opened and the hot water in the hot water storage tank is supplied to the bathtub through the filling tube in response to a filling operation by a user. ,
An auxiliary heat source that activates the auxiliary heat source device when a flow of hot water from the hot water storage tank to the hot water pipe is detected by the water amount sensor and the detected temperature of the hot water temperature sensor is lower than a predetermined target hot water supply temperature; Machine control unit,
A hot water filling start time setting unit that sets a hot water filling start time that is an assumed time at which the hot water operation is started on the day,
A first boiling operation for heating the hot water in the hot water storage tank by operating the tank circulation pump and operating the heat pump at a first capacity before a first predetermined time before the estimated hot water filling time. Then, when the hot water storage amount recognized by the hot water storage amount recognition unit becomes less than or equal to the first hot water storage amount during the execution of the hot water filling operation by the hot water filling control unit, the tank circulation pump is operated. In addition, the heat pump is operated with a second capacity having a higher heating amount for the hot water flowing through the tank circulation path than the first capacity and a lower energy efficiency to heat the hot water in the hot water storage tank. A boiling control unit for executing the operation ,
The boiling control unit, when the hot water storage operation is being performed by the hot water control unit, when the hot water storage amount in the hot water storage tank recognized by the hot water storage amount recognition unit becomes equal to or less than the first hot water storage amount. The second boiling operation is performed for a second predetermined time, and thereafter, the operation is switched to the first boiling operation .

  In the hot water supply system of the present invention, the hot water in the hot water storage tank is heated by the heat pump and boiled, and even if the hot water tank runs out of water, the auxiliary heat source unit can continue to supply hot water from the hot water supply pipe. .

  Also, the estimated filling time is set by the estimated filling time setting unit, and the boiling control unit sets the heat pump to have a higher energy efficiency than the second capacity before the first specified time before the estimated filling time. A first boiling operation operated with the first capacity is started. Thus, the hot water in the hot water storage tank can be efficiently boiled by the estimated hot water filling time to prepare for the start of the hot water filling operation. Further, when the hot water filling operation is started and the hot water storage amount in the hot water storage tank becomes equal to or less than the first hot water storage amount, the boiling controller controls the heat pump to heat the hot water flowing through the tank circulation path more than the first capacity. The second boiling operation which is operated with the second capacity, which is often performed, is executed. As a result, the hot water in the hot water storage tank is quickly heated, and the operating time of the instantaneous heating type auxiliary heat source unit, which has lower energy efficiency and higher running cost than the heat pump, is shortened, and the running cost of hot water filling operation is reduced. Can be achieved.

  In the present invention, the day means the day when the scheduled boiling of the hot water in the hot water storage tank based on the estimated hot water filling start time and the estimated hot water supply start time will be performed.

Furthermore, when the second boiling operation is executed and the amount of hot water stored in the hot water storage tank reaches a certain level, the energy efficiency of the heat pump is switched by switching from the second boiling operation to the first boiling operation. The execution time of the second boiling operation, which is lower than the first boiling operation, can be shortened, and the running cost can be reduced.

Further, the hot water supply system of the present invention
A hot water storage tank in which a water supply pipe is connected to a lower part and a tapping pipe is connected to an upper part, and water supplied from the water supply pipe is stored,
A tank circulation path connecting the lower part and the upper part of the hot water storage tank,
A tank circulation pump that circulates hot water stored in a lower portion of the hot water storage tank to an upper portion of the hot water storage tank through the tank circulation path,
A heat pump that heats hot water flowing through the tank circulation path,
A hot water storage amount recognition unit that recognizes the amount of hot water stored in the hot water storage tank,
A water amount sensor that detects the flow of hot water from the hot water storage tank to the tapping pipe;
A tapping temperature sensor for detecting the temperature of tap water supplied from the tapping pipe,
An instantaneous heating type auxiliary heat source device for heating hot water flowing through the tapping pipe,
A filling pipe branched from the tapping pipe downstream of the heating point by the auxiliary heat source unit and communicated with the bathtub,
A filling valve for opening and closing the filling pipe,
A filling control unit that executes a filling operation in which the filling valve is opened and the hot water in the hot water storage tank is supplied to the bathtub through the filling tube in response to a filling operation by a user. ,
An auxiliary heat source that activates the auxiliary heat source device when a flow of hot water from the hot water storage tank to the hot water pipe is detected by the water amount sensor and the detected temperature of the hot water temperature sensor is lower than a predetermined target hot water supply temperature; Machine control unit,
A hot water filling start time setting unit that sets a hot water filling start time that is an assumed time at which the hot water operation is started on the day,
A first boiling operation for heating the hot water in the hot water storage tank by operating the tank circulation pump and operating the heat pump at a first capacity before a first predetermined time before the estimated hot water filling time. Then, when the hot water storage amount recognized by the hot water storage amount recognition unit becomes less than or equal to the first hot water storage amount during the execution of the hot water filling operation by the hot water filling control unit, the tank circulation pump is operated. In addition, the heat pump is operated with a second capacity having a higher heating amount for the hot water flowing through the tank circulation path than the first capacity and a lower energy efficiency to heat the hot water in the hot water storage tank. A boiling control unit for performing operation,
And a hot water supply end assumed time setting unit for use on the day of hot water to set the hot water supply end assumed time is an expected time to finish,
The boiling control unit stops the heat pump until the next day after the boiling operation end time that is the third predetermined time before the hot water supply end estimated time, and the hot water operation by the hot water control unit starts the boiling operation. The second boiling operation is performed only when started before a time that is a fourth predetermined time before the operation end time, and the filling operation by the filling controller is performed at the boiling operation end time. When started after a time earlier than the fourth predetermined time, only the first boiling operation is performed.

  According to this configuration, when the hot water filling operation is started after the time that is the fourth predetermined time before the boiling operation end time, even if the operation is switched to the second boiling operation, the boiling operation end time will soon be reached. Since the heat pump stops, there is a high possibility that the hot water tank runs out of water and the auxiliary heat source unit operates.

  Therefore, in this case, the first heating operation is continued without switching to the second heating operation, thereby switching to the second heating operation and executing the second heating operation for a short time. A decrease in the energy efficiency of the heat pump can be suppressed.

In addition, a hot water supply start time setting unit that sets a hot water supply start time that is an assumed time when the use of hot water on the day is started,
The boiling control unit heats the hot water in the hot water storage tank by operating the tank circulation pump and operating the heat pump at a third capacity before a fifth predetermined time before the hot water supply start estimated time. A third boiling operation is started, and when the flow of hot water from the hot water storage tank to the tapping pipe is detected by the water amount sensor during the execution of the third boiling operation, the tank circulation pump is operated. Operating the heat pump with a fourth capacity in which the amount of heating of the hot water flowing through the tank circulation path is larger than the third capacity, and switching to a fourth boiling operation for heating the hot water in the hot water storage tank. And

  According to this configuration, when the third boiling operation is being performed from the fifth predetermined time before the estimated hot water supply time, when the flow of hot water from the hot water storage tank to the hot water pipe is detected by the water amount sensor, By switching to the fourth boiling operation in which the amount of heating of the hot water flowing through the tapping pipe is larger than that in the third boiling operation, the hot water in the hot water storage tank can be quickly heated to cope with the use of hot water. Thereby, the operation of the auxiliary heat source unit can be suppressed, and the running cost of hot water supply can be reduced.

  In addition, the boiling control unit may be configured to detect the flow of hot water from the hot water storage tank to the tapping pipe by the water amount sensor during execution of the third boiling operation, and to switch to the fourth boiling operation. When the hot water storage amount in the hot water storage tank recognized by the hot water storage amount recognition unit becomes equal to or greater than the second hot water storage amount, the operation returns to the third boiling operation.

  According to this configuration, after the amount of hot water stored in the hot water storage tank becomes equal to or more than the second hot water storage amount by performing the fourth boiling operation, the operation is returned to the third boiling operation. Thus, the time for boiling the hot water in the hot water storage tank by the fourth boiling operation in which the energy efficiency of the heat pump is lower than the third boiling operation can be shortened, and the running cost can be reduced. .

  In addition, the boiling control unit may be configured to detect the flow of hot water from the hot water storage tank to the tapping pipe by the water amount sensor during execution of the third boiling operation, and to switch to the fourth boiling operation. When the sixth predetermined time has elapsed, the operation is returned to the third boiling operation.

  According to this configuration, after the amount of hot water stored in the hot water storage tank is increased to some extent by the execution of the sixth predetermined time of the fourth boiling operation, the operation is returned to the third boiling operation. Thus, the time for boiling the hot water in the hot water storage tank by the fourth boiling operation in which the energy efficiency of the heat pump is lower than the third boiling operation can be shortened, and the running cost can be reduced. .

  In addition, the boiling control unit is performing the third boiling operation, and within a seventh predetermined time from the start of the third boiling operation, the water amount sensor detects the water amount from the hot water storage tank to the tapping pipe. Only when the flow of hot and cold water is detected, switching to the fourth boiling operation is performed, and after the seventh predetermined time has elapsed from the start of the third boiling operation, the water amount sensor is used. When the flow of hot water from the hot water storage tank to the tapping pipe is detected, the third boiling operation is continued without switching to the fourth boiling operation.

  According to this configuration, after a certain amount of hot water is stored in the hot water storage tank by performing the seventh predetermined time period of the third boiling operation, the third boiling operation is performed without switching to the fourth boiling operation. By continuing the operation, it is possible to prevent the energy efficiency of the heat pump from being reduced due to the switching to the fourth heating operation and the short-time execution of the fourth heating operation.

  Further, the boiling control unit is performing the third boiling operation, and in a state where the hot water storage amount in the hot water storage tank recognized by the hot water storage amount recognition unit is equal to or less than the third hot water storage amount, Switching to the fourth boiling operation is performed only when the flow of hot water from the hot water storage tank to the hot water pipe is detected by the water amount sensor, and the hot water storage tank is recognized by the hot water storage amount recognition unit. When the hot water storage amount is larger than the third hot water storage amount and the flow of hot water from the hot water storage tank to the tapping pipe is detected by the water amount sensor, the switching to the fourth boiling operation is not performed. And the third boiling operation is continued.

  According to this configuration, when the amount of hot water stored in the hot water storage tank is already larger than the third storage amount by performing the third boiling operation, the third boiling operation is not performed without switching to the fourth boiling operation. By continuing the heating operation, it is possible to prevent the energy efficiency of the heat pump from being reduced due to the switching to the fourth heating operation and the short-time execution of the fourth heating operation.

The block diagram of a hot-water supply system. The flowchart of a boiling operation. 4 is a flowchart of a boiling operation during the hot water filling operation. The flowchart of the boiling operation based on the hot water supply start estimated time. The 1st explanatory view showing the execution timing of the boiling operation, and the use condition of hot water. The 2nd explanatory view showing the execution timing of the boiling operation, and the use condition of hot water. The 3rd explanatory view showing the execution timing of the boiling operation, and the use condition of hot water.

  An embodiment of the present invention will be described with reference to FIGS.

[1. Configuration of hot water supply system]
Referring to FIG. 1, hot water supply system 1 of the present embodiment includes hot water storage unit 10, heat pump unit 50, auxiliary heat source device 80, and controller 120 that controls the overall operation of hot water supply system 1. This is a hybrid hot water supply system.

  Although FIG. 1 shows one controller 120 as a controller of hot water supply system 1, a controller of hot water storage unit 10, a controller of heat pump unit 50, and a controller of auxiliary heat source unit 80 are separately provided, and The overall operation of the hot water supply system 1 may be controlled by communication.

  The hot water storage unit 10 includes a hot water storage tank 11, a water supply pipe 12, a tapping pipe 13, and the like. Hot water storage tank 11 stores and retains hot water therein at substantially equal intervals in the height direction, and has tank surface temperature sensors 14 to 14 for detecting temperatures th2 to th5 of hot water in hot water storage tank 11 at each height. 17 and an in-tank temperature sensor 26 which is disposed above the hot water storage tank 11 and detects the temperature th1 of hot water supplied from the hot water storage tank 11 to the tapping pipe 13.

  A tank lower temperature for detecting the temperature th6 of the hot water stored in the lower part of the hot water storage tank 11 is provided near a connection point of the tank circulation path 41 connecting the upper part and the lower part of the hot water storage tank 11 with the lower part of the hot water storage tank 11. A sensor 42 is provided. At the bottom of the hot water storage tank 11, a drain valve 18 that is opened by manual operation of an operator is provided.

  One end of the water supply pipe 12 is connected to a water supply (not shown) via a water supply port 30, and the other end is connected to a lower part of the hot water storage tank 11 to supply water to a lower part in the hot water storage tank 11. The water supply pipe 12 is provided with a pressure-reducing valve 19 for preventing the internal pressure of the hot water storage tank 11 from becoming excessive, and water is allowed to flow only from the water supply pipe 12 to the hot water storage tank 11. A first hot-water-side check valve 20 for preventing outflow of hot water to the pipe 12 is provided.

  The water supply bypass pipe 34 branched from the water supply pipe 12 communicates with the tapping pipe 13 at the connection point X via the hot water supply mixing valve 21, and the hot water supplied from the hot water storage tank 11 to the tapping pipe 13 by the hot water supply mixing valve 21. The mixing ratio with the water supplied from the water supply bypass pipe 34 to the tapping pipe 13 is changed.

  The feedwater bypass pipe 34 has a feedwater temperature sensor 22 that detects the temperature Tw (hereinafter, referred to as feedwater temperature Tw) of the water supplied to the feedwater bypass pipe 34 and a flow rate Fw of the water flowing through the feedwater bypass pipe 34. A water-side flow sensor 23 and a water-side check valve 24 that allows water to flow only in the direction from the water supply bypass pipe 34 to the tapping pipe 13 and prevents the flow of hot water from the tapping pipe 13 to the feedwater bypass pipe 34. Are provided.

  The tapping pipe 13 has one end connected to the hot water supply port 31 and the other end connected to an upper portion of the hot water storage tank 11. The hot water stored in the upper part of the hot water storage tank 11 is supplied from a hot water supply pipe 13 to a hot water tap (not shown) (a kitchen, a washroom, a bathroom curan or a shower, etc.) via a hot water supply port 31. A second hot-water check valve 25 that allows water to flow only in the direction from the hot-water storage tank 11 to the hot-water supply pipe 13 to the hot-water storage pipe 11 to prevent the flow of hot water from the hot-water supply pipe 13 to the hot-water storage tank 11 side. And a hot water side flow sensor 27 for detecting a flow rate Fh of hot water supplied from the hot water storage tank 11 to the hot water pipe 13.

  The auxiliary heat source device 80 is provided at a location downstream of the connection point X of the tapping pipe 13 with the water supply bypass pipe 34, and the hot water storage unit 10 bypasses the auxiliary heat source device 80 and is located downstream of the auxiliary heat source device 80. A hot-water bypass pipe 33 that connects the hot-water tap pipe 13 on the upstream side and a hot-water tapping valve 33 that opens and closes the hot-water bypass pipe 33 is provided.

  Between the branch point Y of the tapping pipe 13 and the tapping bypass pipe 33 and the hot water supply mixing valve 21, a mixing temperature sensor 28 for detecting the temperature Tm of hot water supplied to the tapping pipe 13 via the hot water supply mixing valve 21 is provided. A hot water supply temperature sensor 32 for detecting the temperature of hot water discharged from hot water supply port 31 is provided between hot water supply port 31 and junction Z of hot water supply pipe 13 with hot water bypass pipe 33.

  The detection signal of each sensor provided in hot water storage unit 10 is input to controller 120. The operation of the hot water supply mixing valve 21 and the hot water bypass valve 29 is controlled by a control signal output from the controller 120.

  Next, the heat pump unit 50 circulates the hot water in the hot water storage tank 11 through the tank circulation path 41 to heat it, and is installed outdoors. The heat pump unit 50 includes an evaporator 53, a compressor 54, and a heat pump heat exchanger 55 (condenser) connected by a heat pump circuit 52 in which a heat medium (an alternative fluorocarbon such as hydrofluorocarbon (HFC) or carbon dioxide) is sealed. ), And a heat pump 51 constituted by an expansion valve 56.

  The evaporator 53 performs heat exchange between air (outside air) supplied by rotation of the fan 60 and a heat medium flowing in the heat pump circulation path 52. The compressor 54 compresses the heat medium discharged from the evaporator 53 to a high pressure and high temperature, and sends the heat medium to the heat pump heat exchanger 55. The expansion valve 56 releases the pressure of the heat medium pressurized by the compressor 54.

  The defrost valve 61 is provided so as to bypass the expansion valve 56, and defrosts the evaporator 53 with the heat medium sent from the compressor 54. Heat medium temperature sensors 62, 63 for detecting the temperature of the heat medium flowing in the heat pump circulation path 52 are provided upstream and downstream of the expansion valve 56 of the heat pump circulation path 52 and upstream and downstream of the compressor 54. 64 and 65 are provided respectively. Further, the evaporator 53 is provided with an ambient temperature sensor 67 for detecting the temperature Tout of the air taken into the evaporator 53.

  The heat pump heat exchanger 55 is connected to the tank circulation path 41, and circulates in the tank circulation path 41 by heat exchange between the heat medium of high pressure and high temperature by the compressor 54 and hot water flowing in the tank circulation path 41. Heat the hot water. The tank circulation path 41 is provided with a tank circulation pump 66 for circulating the hot water in the hot water storage tank 11 through the tank circulation path 41.

  Hot water stored in the lower part of the hot water storage tank 11 is guided to the tank circulation path 41 by the tank circulation pump 66, heated to a predetermined temperature (boiling temperature) by the heat pump heat exchanger 55, and returned to the upper part of the hot water storage tank 11. . As a result, hot water of a predetermined temperature is sequentially stacked and stored from above the hot water storage tank 11.

  On the upstream and downstream sides of the heat pump heat exchanger 55 in the tank circulation path 41, hot water temperature sensors 68 and 69 for detecting the temperature of hot and cold water flowing in the tank circulation path 41 are provided. The heat pump heat exchanger 55 is provided with a condensing temperature sensor 57 for detecting the condensing temperature of the heat medium condensing inside.

  The detection signal of each sensor provided in the heat pump unit 50 is input to the controller 120. Further, the operation of the compressor 54, the expansion valve 56, the tank circulation pump 66, and the fan 60 is controlled by a control signal output from the controller 120.

  Next, the auxiliary heat source device 80 is for heating hot water flowing through the tapping pipe 13 and includes a hot water supply burner 81 housed in a can 87 and a hot water supply heat exchanger 82 heated by the hot water supply burner 81. ing.

  The hot water supply pipe 100 communicating with the bathtub 105 is connected to a location on the tapping pipe 13 downstream of the location of the hot water supply heat exchanger 82. The filling pipe 100 is provided with a filling valve 103 for opening and closing the filling pipe 100, and the controller 120 opens the filling valve 103, so that the filling pipe 13 is opened via the filling pipe 100. Hot water is supplied to bathtub 105.

  Fuel gas is supplied to the hot water supply burner 81 from a gas supply pipe (not shown), and combustion air is supplied by a combustion fan (not shown). The controller 120 controls the amount of combustion of the hot water supply burner 81 by adjusting the flow rates of the fuel gas and the combustion air supplied to the hot water supply burner 81.

  The hot water supply heat exchanger 82 is connected in the middle of the hot water supply pipe 13, and heats hot and cold water flowing inside by the combustion heat of the hot water supply burner 81. The tapping pipe 13 is provided with a water stop valve 93 and a water amount sensor 88 in order from the upstream side. The upstream side and the downstream side of the hot water supply heat exchanger 82 are connected by a heat source bypass pipe 89, and the heat source bypass pipe 89 is provided with a heat source bypass valve 90 for adjusting the opening degree of the heat source bypass pipe 89. I have. A heat exchange hot water temperature sensor 91 is provided near the outlet of the hot water supply heat exchanger 82 of the hot water supply pipe 13, and a heat source hot water temperature sensor 92 (the present invention) is provided downstream of the connection point of the hot water supply pipe 13 with the heat source bypass pipe 89. Is provided.

  With this configuration, when there is no hot water in the hot water storage tank 11 (when the hot water is out of water), the water supplied from the water supply pipe 12 to the hot water supply pipe 13 via the hot water storage tank 11 and the water supply bypass pipe 34 generates hot water. The hot water is heated by the exchanger 82 and mixed with water from the heat source bypass pipe 89, so that hot water at the target hot water supply temperature is supplied from the hot water supply port 31.

  A detection signal of each sensor provided in the auxiliary heat source device 80 is input to the controller 120. The operation of the hot water supply burner 81, the heat source bypass valve 90, and the filling valve 103 is controlled by a control signal output from the controller 120.

  The controller 120 is an electronic circuit unit composed of a CPU, a memory, and the like (not shown). The controller 120 executes a control program for the hot water supply system 1 stored in the memory by the CPU, so that the hot water supply control unit 121 and the filling control unit are provided. 122, a boiling water control unit 123, a hot water storage amount recognition unit 124, a hot water supply start time setting unit 125, a hot water filling start time setting unit 126, and a hot water supply end time setting unit 127 function.

  The controller 120 is connected to the remote controller 140 via a communication cable 130. The remote controller 140 includes a display 141 for displaying the operating status of the hot water supply system 1, setting of operating conditions, and the like, and a switch unit 142 provided with various switches. The user of the hot water supply system 1 operates the switch section 142 of the remote control 140 to set the hot water supply temperature (target hot water supply temperature) from the hot water supply port 31 and to set the hot water supply temperature to the bathtub 105 in the hot water filling operation (target hot water filling). The temperature and the filling amount (target filling amount) are set.

  The hot water supply control unit 121 detects the mixing temperature sensor 28 or the hot water supply temperature sensor 32 when the hot water storage tank 11 has not run out of hot water and the water-side flow sensor 23 detects the flow of water equal to or more than the lower limit flow rate. Mixing temperature control is performed to adjust the distribution ratio of hot water mixing valve 21 so that the detected temperature becomes the target hot water supply temperature. At this time, hot water supply control section 121 closes hot water bypass valve 29 when hot water filling valve 103 is opened and hot water supply to bathtub 105 is being performed, and when hot water filling valve 103 is closed. The hot water bypass valve 29 is opened.

  Hot water supply control unit 121 closes hot water supply bypass valve 29 when hot water storage tank 11 is running out of hot water and water flow rate equal to or higher than the lower limit flow rate is detected by water side flow sensor 23. . Heating temperature control for adjusting the combustion amount of the hot water supply burner 81 so that the detected temperature of the heat source hot water temperature sensor 92 becomes the target hot water supply temperature when the water flow sensor 88 detects the flow of water equal to or more than the lower limit flow rate. Execute The configuration in which the hot water supply control unit 121 executes the heating temperature adjustment control in this way corresponds to the auxiliary heat source device control unit of the present invention.

  The bath filling control unit 122 finishes filling the bath tub 105 when the operation of instructing the filling (the filling operation) is performed by the switch unit 142 of the remote control 140 or at a preset reservation time. Thus, the filling operation is performed in which the filling valve 103 is opened to supply the target filling amount of hot water from the tapping pipe 13 to the bathtub 105 via the filling pipe 100. The hot water controller 122 sets the target hot water temperature to the target hot water supply temperature and executes the hot water operation.

  The hot water storage amount recognition unit 124 recognizes the amount of hot water (hot water storage amount) stored in the hot water storage tank 11 by monitoring the detected temperatures of the in-tank temperature sensor 26 and the tank surface temperature sensors 14 to 17. From the total amount of hot water in hot water storage tank 11 (= capacity of hot water storage tank 11) in a state where boiling of hot water storage tank 11 has been completed (full storage state), the flow rate of hot water supplied from hot water storage tank 11 to hot water supply pipe 13 (= The hot water storage amount may be recognized by subtracting the integrated value of the hot water side flow sensor 27) or by subtracting the estimated hot water supply amount from the hot water supply time from the hot water storage tank 11 to the tapping pipe. Good.

  The boiling controller 123 activates the tank circulation pump 66 and the heat pump 51 when the remaining amount of hot water in the hot water storage tank 11 recognized by the hot water storage amount recognition unit 124 becomes equal to or less than the lower limit, and the hot water storage tank 11 A boiling operation is performed in which the hot and cold water is heated to, for example, 45 ° C. in accordance with the set hot water supply temperature.

  In addition, boiling controller 123 executes planned boiling of hot water in hot water storage tank 11 in order to secure the amount of hot water stored in hot water storage tank 11 in preparation for a time slot in which hot water is expected to be used.

[2. Planned boiling of hot water in hot water storage tank]
Next, according to the flowcharts shown in FIGS. 2 to 4, execution of the planned boiling of the hot water in the hot water storage tank 11 will be described.

  Referring to FIG. 2, controller 120 determines in STEP 1 whether the current time (recognized by a clock circuit (not shown)) has reached the date update timing (2 o'clock). When the current time reaches the date update timing, the process proceeds to STEP2.

  STEP 2 is a process performed by the estimated hot water supply start time setting unit 125, the estimated hot water filling start time setting unit 126, and the estimated hot water supply end time setting unit 127. The controller 120 stores past hot water usage status data (hot water supply status data) in units of one day (0:00 to 24:00), and the hot water supply start estimated time setting unit 125 performs the processing based on the hot water supply status data. An estimated hot water supply start time S1, which is a time at which the use of hot water is assumed to be started on the day (a day when the planned boiling operation is to be executed) is set.

  Similarly, the estimated filling time setting unit 126 sets the estimated filling start time B1, which is the time at which the filling operation is assumed to be started on the day, based on the hot water supply status data. Further, hot water supply end time setting section 127 sets hot water supply end time G1, which is a time at which use of hot water is assumed to end on the day, based on the hot water supply status data.

  Here, in FIG. 5, the horizontal axis is a common time axis, the vertical axis is set to the capacity of the heat pump 51 in the upper part, and the execution timing of the boiling operation in the time zone of one day (0:00 to 24:00) is shown. In the lower part of the figure, the vertical axis is set to the hot water supply flow rate (detected by the water amount sensor 88), and the amount of hot water used (hot water supply flow rate) in the time zone of one day (0:00 to 24:00) is illustrated. . In the example of FIG. 5, 2:00 is set as the date update timing, hot water supply start time S1 is 6:00, hot water filling start time B1 is 20:00, and hot water supply end time G1 is 24:00.

  STEP3 to STEP8 in FIG. 2 are processing by the boiling control unit 123. Boiling control unit 123 waits in STEP 3 for the current time to reach time S0 (see FIG. 5) that is earlier by α (corresponding to the fifth predetermined time of the present invention) than hot water supply start estimated time S1 and then proceeds to STEP4. Then, the first boiling operation (corresponding to the first boiling operation and the third boiling operation of the present invention) is executed to boil the hot water in the hot water storage tank 11.

  Here, the first boiling operation is performed by operating the tank circulation pump 66 and operating the heat pump 51 at the first capacity A1 (corresponding to the first capacity and the third capacity of the present invention). Heat the hot water inside. In this case, the circulation flow rate of hot water by the tank circulation pump 66 is adjusted so that the temperature detected by the hot water temperature sensor 69 becomes the boiling temperature. Α is set such that boiling of hot water in hot water storage tank 11 is completed at hot water supply start estimated time S1.

  In the present embodiment, both the heating based on the estimated hot water supply start time S1 executed in STEP 4 and the heating based on the estimated hot water filling start time B1 executed in STEP 6, which will be described later, depend on the capacity of the heat pump 51. Although the first boiling operation is performed with one capacity A1, the capacity of the heat pump 51 may be changed.

  In this case, the capacity of the heat pump 51 when performing the heating based on the estimated hot water supply start time S1 corresponds to the third capacity of the present invention, and the heating operation with the third capacity corresponds to the third heating operation of the present invention. Equivalent to. Further, the capacity of the heat pump 51 when performing boiling based on the estimated filling time B1 corresponds to the first capacity of the present invention, and the boiling operation based on the first capacity corresponds to the first boiling operation of the present invention. I do.

  When the boiling of the hot water in the hot water storage tank 11 by the first boiling operation is completed in STEP4, the process proceeds to STEP5. Then, the boiling control unit 123 waits in STEP5 for the current time to become the time B0 (see FIG. 5) that is β (corresponding to the first predetermined time of the present invention) earlier than the estimated hot water filling time B1. Then, the process proceeds to STEP6, where the first boiling operation is executed to boil the hot water in the hot water storage tank 11. Here, β is set so that the boiling of the hot water in the hot water storage tank 11 is completed at the estimated hot water filling time B1.

  In the next STEP7, the process waits until the current time reaches a time G0 (boiling operation end time) that is γ (assumed in the third predetermined time of the present invention) earlier than the hot water supply end estimated time G1, and proceeds to STEP8. Boiling control unit 123 keeps heat pump 51 stopped until the next day.

  In the example shown in FIG. 5, around 6:00 (wake up to breakfast), around 12:00 (lunch time), around 20:00 (hot water to bath time), around 24:00 (before going to bed) Hot water is used during the time period).

[3. Boiling of hot water in hot water storage tank with hot water filling operation]
Next, a process of boiling hot water in the hot water storage tank 11 performed by the boiling control unit 123 in accordance with the hot water filling operation will be described with reference to the flowchart shown in FIG.

  Boiling control unit 123 determines whether or not the filling operation is being performed in STEP 10 of FIG. Then, when the hot water filling operation is being performed, the process proceeds to STEP 11, and the boiling control unit 123 determines whether or not the hot water storage amount in the hot water storage tank 11 recognized by the hot water storage amount recognition unit 124 is equal to or less than the first hot water storage amount. I do. When the amount of hot water stored in the hot water storage tank 11 is equal to or less than the first hot water storage amount, the process proceeds to STEP 12, and when the amount of hot water stored in the hot water storage tank 11 is larger than the first hot water storage amount, the process returns to STEP 10.

  Here, in accordance with the supply of hot water from hot water storage tank 11 to hot water supply pipe 13, water is supplied to water supply pipe 12 at a lower portion of hot water storage tank 11, and the energy efficiency of boiling by heat pump 51 is reduced. It is set assuming a situation where the level is equal to or higher than a predetermined level.

  In STEP 12, the boiling control unit 123 determines whether the current time is before e (corresponding to the fourth predetermined time of the present invention) before the boiling operation end time G0. When the current time is earlier than the boiling operation end time G0 by e, the process proceeds to STEP13, and when the current time is not earlier than the boiling operation end time G0 by e, the process branches to STEP20.

  In STEP13, the boiling control unit 123 operates the tank circulation pump 66 and operates the heat pump 51 at the second capacity A2 to execute the second boiling operation for boiling the hot water in the hot water storage tank 11. Here, the second capacity A2 has a larger heating amount applied to the hot and cold water flowing through the tank circulation path 41 than the first capacity A1, and the energy efficiency of the heat pump 51 is lower.

  The energy efficiency of the heat pump 51 is represented by, for example, a coefficient of performance COP (heating amount / power consumption).

  As described above, when the hot water storage tank 11 runs out of hot water during the filling operation, the second pumping operation of operating the heat pump 51 with the second capacity A2 having a larger heating amount than the first capacity A1 is performed. Thereby, the boiling speed of hot water in hot water storage tank 11 can be increased, and the time during which auxiliary heat source device 80 operates can be reduced. Thus, the operating time of the auxiliary heat source device 80, which has a higher running cost than the heat pump 51, can be shortened, and the running cost required for the filling operation can be reduced.

  FIG. 5 shows that the filling operation is started after the boiling of the hot water in the hot water storage tank 11 is completed by the first boiling operation, and the amount of hot water stored in the hot water storage tank 11 becomes equal to or less than the first hot water storage amount and the second boiling operation is performed. This shows a case where a raising operation is performed. In the example of FIG. 5, the second boiling operation in which the capacity of the heat pump 51 is set to the second capacity A2 is continued until the boiling of the hot water in the hot water storage tank 11 is completed.

  On the other hand, in the flowchart of FIG. 3, after starting the second boiling operation in STEP13, the boiling control unit 123 waits for the elapse of T1 (corresponding to the second predetermined time of the present invention) in STEP14, and then proceeds to STEP15. Then, the process is switched from the second heating operation to the first heating operation to heat the hot water in the hot water storage tank 11, and the process proceeds to STEP16 to end the process.

  FIG. 6 shows the boiling operation accompanying the hot water filling operation, the second boiling operation during the first T1 period (immediately after 20:00 to t3), and the first boiling operation after the elapse of T1. Is performed by switching to. By performing the second boiling operation only during the first period of T1, the boiling water in the hot water storage tank 11 is quickly raised and the filling is advanced to some extent, or the filling is terminated. After the boiling of the hot water in the hot water storage tank 11 becomes unnecessary, the energy efficiency of the heat pump 51 can be increased to reduce the running cost required for boiling the hot water in the hot water storage tank 11.

  When the process branches from STEP 12 to STEP 20, the boiling control unit 123 executes the first boiling operation to boil the hot water in the hot water storage tank, and proceeds to STEP 16 to perform processing. In this case, the second boiling operation is not performed.

  FIG. 7 shows a case in which the boiling with the hot water filling operation is performed only by the first boiling operation. In the example of FIG. 7, since the time t5 at which the hot water filling operation is started is not before e before the boiling operation end time G0, the first boiling operation for operating the heat pump 51 at the first capacity A1 is only performed for a short time. The first boiling operation has been completed at the boiling operation end time G0. In this case, since the time for operating the heat pump 51 and performing the boiling operation is short, the timing at which the hot water storage tank 11 runs out of hot water due to the hot water filling operation is accelerated, and the hot water filling operation is performed by operating the auxiliary heat source device 80. The time gets longer.

  As described above, when the time for performing the filling operation by operating the auxiliary heat source device 80 is long, even if the second boiling operation is performed for a short time, the effect obtained by increasing the heating amount of the heat pump 51 is low. Therefore, by performing the first boiling operation, the total running cost of hot water supply can be reduced.

[4. Boiling of hot water in hot water storage tank based on estimated hot water supply start time]
Next, the process of boiling hot water in hot water storage tank 11 based on estimated hot water supply start time S1 executed by boiling control unit 123 will be described with reference to the flowchart shown in FIG.

  In STEP 30 of FIG. 4, boiling control section 123 determines whether or not the first boiling operation is being performed based on hot water supply start estimated time S <b> 1, and when the first boiling operation is being performed, STEP 31. Proceed to. In STEP 31, the boiling control unit 123 determines whether or not the detected flow rate Fm of the water amount sensor 88 is equal to or more than the lower limit flow rate (whether or not the flow of hot water from the hot water storage tank 11 to the hot water pipe 13 is detected). If the detected flow rate Fm is equal to or greater than the lower limit flow rate, the process proceeds to STEP 32, and if the detected flow rate Fm is less than the lower limit flow rate, the process returns to STEP 30.

  In STEP32, the boiling control unit 123 determines whether or not d (corresponding to the seventh predetermined time of the present invention) has elapsed from the time S0 when the first boiling operation was started. If the time d has not elapsed since the time S0 when the first boiling operation was started, and it can be determined that the boiling of the hot water in the hot water storage tank 11 has not progressed so much, the process proceeds to STEP 33, and the process proceeds to the second boiling operation. Switch.

  In step 34, the process waits until T2 (corresponding to the sixth predetermined time of the present invention) elapses, and proceeds to step 35, in which the boiling control unit 123 returns from the second boiling operation to the first boiling operation and returns to the hot water storage tank. The boiling of the hot water in 11 is completed, and the process proceeds to STEP 36 to end the process.

  FIG. 6 illustrates a case where the use of hot water is started at t1 before the lapse of d from S0 after the first boiling operation in which the heat pump 51 is operated at the first capacity A1 is started at S0. It is illustrated. In FIG. 6, the operation is switched to the second heating operation in which the heat pump 51 is operated at the second capacity A2 at t1, and the operation is returned to the first heating operation at t2 when T2 has elapsed from t1.

  As described above, by switching to the second boiling operation when the use of hot water is started before the boiling of the hot water in the hot water storage tank 11 is completed after the first boiling operation is started in S0, By quickly heating the hot water in the hot water storage tank 11, the operation of the auxiliary heat source device 80 is suppressed, and the running cost of hot water supply can be reduced.

  Further, at time t2 when the boiling of the hot water in the hot water storage tank 11 has advanced to some extent, the energy efficiency of the heat pump 51 is increased by returning from the second boiling operation to the first boiling operation, and the hot water in the hot water storage tank 11 is increased. The running cost of boiling can be reduced.

  On the other hand, in STEP 32, when d or more has elapsed from the time S0 at which the first boiling operation was started, the process branches to STEP 40, and the boiling control unit 123 continues the first boiling operation to keep the water in the hot water storage tank 11 hot. Is completed, and the process proceeds to STEP 36 to end the process.

  FIG. 7 illustrates a case where the use of hot water is started at t4 after d or more has elapsed from S0 after the first boiling operation in which the heat pump 51 is operated at the first capacity A1 is started at S0. ing. In FIG. 7, even if the use of hot water is started at t4, the first boiling operation is continuously performed without switching to the second boiling operation.

  As described above, after the first boiling operation is started in S0, when the use of the hot water in the hot water storage tank 11 is advanced to a certain extent after the elapse of d or more and the use of the hot water is started, the water is already heated. It is assumed that the hot water in the hot water storage tank 11 can support hot water supply. Therefore, in this case, by lowering the energy efficiency of the heat pump 51 due to the switching to the second boiling operation, the first boiling operation is continued without switching to the second boiling operation. Thus, the running cost of hot water supply can be reduced.

  Note that, in the present embodiment, the case where the use of hot water is started during boiling in the hot water filling operation in STEP12 to STEP13 in FIG. 3 and during the heating based on the estimated hot water supply start time S1 in STEP32 to STEP33 in FIG. The heating is performed by the second heating operation in which the capacity of the heat pump 51 is set to the second capacity A2, but the capacity of the heat pump 51 may be changed.

  In this case, the capacity of the heat pump 51 when performing the boiling according to STEP12 to STEP13 of FIG. 3 corresponds to the second capacity of the present invention, and the boiling operation with the second capacity is the same as the second boiling operation of the present invention. Equivalent to. Further, the capacity of the heat pump 51 when performing the boiling according to STEP32 to STEP33 in FIG. 4 corresponds to the fourth capacity of the present invention, and the boiling operation based on the fourth capacity corresponds to the fourth boiling operation of the present invention.

[5. Other Embodiments]
In the above embodiment, when the use of hot water is started before d has elapsed from the start time S0 of the first boiling operation in STEP32 of FIG. 4, the operation is switched to the second boiling operation. When the use of hot water is started before the amount of hot water in the hot water storage tank 11 recognized by the amount recognizing unit 124 becomes equal to or more than the third hot water storage amount, the operation may be switched to the second boiling operation.

  Further, in the above embodiment, in STEP 34 of FIG. 4, when the execution time of the second boiling operation is equal to or longer than T2, the operation is returned to the first boiling operation. When the hot water storage amount in the hot water storage tank 11 becomes equal to or more than the second hot water storage amount, the operation may be returned to the first boiling operation.

  Further, in the above-described embodiment, the auxiliary heat source device 80 using the hot water supply burner 81 for burning fuel gas as a heating source as the auxiliary heat source device of the present invention is described, but an instantaneous heating type using a petroleum burner, an electric heater or the like as a heating source is described. May be used.

  Further, in the above-described embodiment, the heat pump unit 50 is shown as the heat pump of the present invention. However, the heat pump unit is not limited to this configuration. For example, the present invention can be applied.

  DESCRIPTION OF SYMBOLS 1 ... Hot water supply system, 10 ... Hot water storage unit, 11 ... Hot water storage tank, 12 ... Water supply pipe, 13 ... Hot water supply pipe, 41 ... Tank circulation path, 50 ... Heat pump unit, 51 ... Heat pump, 66 ... Tank circulation pump, 80 ... Auxiliary heat source Machine 88 water sensor, 100 hot water pipe, 103 hot water filling valve, 105 bathtub, 120 controller, 121 hot water supply control section, 122 hot water control section, 123 hot water control section, 124 hot water storage Amount recognizing unit, 125: hot water supply start time setting unit, 126: hot water filling start time setting unit, 127: hot water supply end time setting unit.

Claims (7)

A hot water storage tank in which a water supply pipe is connected to a lower part and a tapping pipe is connected to an upper part, and water supplied from the water supply pipe is stored,
A tank circulation path connecting the lower part and the upper part of the hot water storage tank,
A tank circulation pump that circulates hot water stored in a lower portion of the hot water storage tank to an upper portion of the hot water storage tank through the tank circulation path,
A heat pump that heats hot water flowing through the tank circulation path,
A hot water storage amount recognition unit that recognizes the amount of hot water stored in the hot water storage tank,
A water amount sensor that detects the flow of hot water from the hot water storage tank to the tapping pipe;
A tapping temperature sensor for detecting the temperature of tap water supplied from the tapping pipe,
An instantaneous heating type auxiliary heat source device for heating hot water flowing through the tapping pipe,
A filling pipe branched from the tapping pipe downstream of the heating point by the auxiliary heat source unit and communicated with the bathtub,
A filling valve for opening and closing the filling pipe,
A filling control unit that executes a filling operation in which the filling valve is opened and the hot water in the hot water storage tank is supplied to the bathtub through the filling tube in response to a filling operation by a user. ,
An auxiliary heat source that activates the auxiliary heat source device when a flow of hot water from the hot water storage tank to the hot water pipe is detected by the water amount sensor and the detected temperature of the hot water temperature sensor is lower than a predetermined target hot water supply temperature; Machine control unit,
A hot water filling start time setting unit that sets a hot water filling start time that is an assumed time at which the hot water operation is started on the day,
A first boiling operation for heating the hot water in the hot water storage tank by operating the tank circulation pump and operating the heat pump at a first capacity before a first predetermined time before the estimated hot water filling time. Then, when the hot water storage amount recognized by the hot water storage amount recognition unit becomes less than or equal to the first hot water storage amount during the execution of the hot water filling operation by the hot water filling control unit, the tank circulation pump is operated. In addition, the heat pump is operated with a second capacity having a higher heating amount for the hot water flowing through the tank circulation path than the first capacity and a lower energy efficiency to heat the hot water in the hot water storage tank. A boiling control unit for executing the operation ,
The boiling control unit, when the hot water storage operation is being performed by the hot water control unit, when the hot water storage amount in the hot water storage tank recognized by the hot water storage amount recognition unit becomes equal to or less than the first hot water storage amount. Hot water supply system , wherein the second heating operation is performed for a second predetermined time, and thereafter, the operation is switched to the first heating operation. A hot water storage tank in which a water supply pipe is connected to a lower part and a tapping pipe is connected to an upper part, and water supplied from the water supply pipe is stored,
A tank circulation path connecting the lower part and the upper part of the hot water storage tank,
A tank circulation pump that circulates hot water stored in a lower portion of the hot water storage tank to an upper portion of the hot water storage tank through the tank circulation path,
A heat pump that heats hot water flowing through the tank circulation path,
A hot water storage amount recognition unit that recognizes the amount of hot water stored in the hot water storage tank,
A water amount sensor that detects the flow of hot water from the hot water storage tank to the tapping pipe;
A tapping temperature sensor for detecting the temperature of tap water supplied from the tapping pipe,
An instantaneous heating type auxiliary heat source device for heating hot water flowing through the tapping pipe,
A filling pipe branched from the tapping pipe downstream of the heating point by the auxiliary heat source unit and communicated with the bathtub,
A filling valve for opening and closing the filling pipe,
A filling control unit that executes a filling operation in which the filling valve is opened and the hot water in the hot water storage tank is supplied to the bathtub through the filling tube in response to a filling operation by a user. ,
An auxiliary heat source that activates the auxiliary heat source device when a flow of hot water from the hot water storage tank to the hot water pipe is detected by the water amount sensor and the detected temperature of the hot water temperature sensor is lower than a predetermined target hot water supply temperature; Machine control unit,
A hot water filling start time setting unit that sets a hot water filling start time that is an assumed time at which the hot water operation is started on the day;
A first boiling operation for heating the hot water in the hot water storage tank by operating the tank circulation pump and operating the heat pump at a first capacity before a first predetermined time before the estimated hot water filling time. Then, when the hot water storage amount recognized by the hot water storage amount recognition unit becomes less than or equal to the first hot water storage amount during the execution of the hot water filling operation by the hot water filling control unit, the tank circulation pump is operated. In addition, the second pump that heats the hot water in the hot water storage tank by operating the heat pump with the second power having a larger heating amount for the hot water flowing through the tank circulation path than the first capacity and having a lower energy efficiency. A boiling control unit for performing operation,
A hot water supply end time setting unit that sets a hot water supply end time that is an assumed time at which the use of hot water on the day ends.
With
The boiling control unit stops the heat pump until the next day after the boiling operation end time that is the third predetermined time before the hot water supply end estimated time, and the hot water operation by the hot water control unit starts the boiling operation. The second boiling operation is performed only when started before a time that is a fourth predetermined time before the operation end time, and the filling operation by the filling controller is performed at the boiling operation end time. The hot water supply system according to claim 1, wherein when started after a time earlier than the fourth predetermined time, only the first boiling operation is performed. In the hot water supply system according to claim 1 or 2 ,
A hot water supply start time setting unit that sets a hot water start start time that is an assumed time at which use of hot water is started on the day,
The boiling control unit heats the hot water in the hot water storage tank by operating the tank circulation pump and operating the heat pump at a third capacity before a fifth predetermined time before the hot water supply start estimated time. A third boiling operation is started, and when the flow of hot water from the hot water storage tank to the tapping pipe is detected by the water amount sensor during the execution of the third boiling operation, the tank circulation pump is operated. Operating the heat pump with a fourth capacity in which the amount of heating of the hot water flowing through the tank circulation path is larger than the third capacity, and switching to a fourth boiling operation for heating the hot water in the hot water storage tank. And hot water supply system. The hot water supply system according to claim 3 ,
The boiling control unit detects the flow of hot water from the hot water storage tank to the tapping pipe by the water amount sensor during execution of the third boiling operation, and switches to the fourth boiling operation. A hot water supply system comprising: returning to the third boiling operation when the hot water storage amount in the hot water storage tank recognized by the hot water storage amount recognition unit becomes equal to or greater than a second hot water storage amount. The hot water supply system according to claim 3 ,
The boiling control unit detects the flow of hot water from the hot water storage tank to the tapping pipe by the water amount sensor during the execution of the third boiling operation, and switches to the fourth boiling operation. (6) The hot water supply system, wherein the operation returns to the third boiling operation when a predetermined time has elapsed. In the hot water supply system according to any one of claims 3 to 5 ,
The boiling control unit is performing the third boiling operation, and within a seventh predetermined time from the start of the third boiling operation, using the water amount sensor to supply the hot water from the hot water storage tank to the hot water pipe. Switching to the fourth boiling operation is performed only when the flow of water is detected, and after the seventh predetermined time has elapsed from the start of the third boiling operation, the hot water storage tank is detected by the water amount sensor. And when the flow of hot water to the hot water supply pipe is detected, the third heating operation is continued without switching to the fourth heating operation. In the hot water supply system according to any one of claims 3 to 5 ,
The boiling control unit may be configured to execute the third boiling operation, wherein the hot water storage amount in the hot water storage tank recognized by the hot water storage amount recognition unit is equal to or less than the third hot water storage amount. Only when the flow of hot water from the hot water storage tank to the hot water supply pipe is detected is switched to the fourth boiling operation, and the hot water storage in the hot water storage tank recognized by the hot water storage amount recognition unit is performed. When the flow rate of the hot water from the hot water storage tank to the tapping pipe is detected by the water amount sensor in a state where the amount is larger than the third hot water storage amount, the switch to the fourth boiling operation is not performed, A hot water supply system wherein the third boiling operation is continued.