JP2015227757A - Hot water storage type water heater - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hot water storage type water heater capable of securing stability of a hot water supply temperature and suppressing deterioration in boiling-up efficiency.SOLUTION: A hot water storage type water heater comprises: a heat exchanger 52 for hot water supply which exchanges heat between hot water in a hot water storage tank 8 and fed hot water; a hot water supply source conduit 46 for guiding from the upper part of the hot water storage tank 8 to the lower part of the hot water storage tank 8 via the heat exchanger 52 for hot water supply; a water feed conduit 9 which guides fed hot water to a hot water supply terminal via the heat exchanger 52 for hot water supply; a hot water supply source pump 48 which circulates the hot water in the hot water supply source conduit 46; and a control unit 36. The control unit 36 controls the output of the hot water supply source pump 48 so that a heat source-side flow rate Fl is equal to or larger than a water feed-side flow rate Fk when the water feed-side flow rate Fk is equal to or larger than a flow rate threshold, and also controls the output of the hot water supply source pump 48 so that the heat source-side flow rate Fl is less than the water feed-side flow rate Fk when the water feed-side flow rate Fk is smaller than the flow rate threshold.

Description

  TECHNICAL FIELD The present invention relates to a hot water storage type hot water heater that supplies hot water by heating hot water stored in a hot water storage tank as a heat source.

  2. Description of the Related Art Conventionally, a so-called indirect hot water heater in which hot water and hot water supplied from the upper part of a hot water storage tank are heat-exchanged by a heat exchanger is known. Patent Document 1 discloses the configuration of such an indirect hot water heater. Further, in the water heater described in Patent Document 1, the driving force of the pump is controlled according to the flow rate of hot water on the hot water side flowing out from the heat exchanger, and the circulation flow rate of the fluid on the heat source side is increased or decreased.

JP-A-5-99507

  By the way, in the indirect hot water supply type water heater of the above-mentioned Patent Document 1, the flow rate of hot water flowing through the heat source side of the heat exchanger (hereinafter referred to as water supply side flow rate) according to the flow rate of hot water flowing through the water supply side of the heat exchanger (hereinafter referred to as water supply side flow rate) ( Hereinafter, the heat source side flow rate) is controlled. As such control, for example, it is conceivable to control the ratio of the water supply side flow rate and the heat source side flow rate to be constant (for example, the water supply side flow rate and the heat source side flow rate are the same). However, when the water supply side flow rate increases, the amount of heat that passes through the heat exchanger without heat exchange from the heat source side to the hot water supply side increases. For this reason, the temperature of the hot water derived from the heat exchanger decreases as the flow rate on the water supply side increases, and conversely, the temperature of the hot water on the heat source side derived from the heat exchanger increases. . Furthermore, the temperature of hot water derived from the hot water supply side of the heat exchanger is affected not only by the amount of heat exchange in the heat exchanger but also by the temperature of city water introduced to the water supply side of the heat exchanger. For this reason, there is a possibility that a stable hot water supply temperature cannot be realized in the above-described conventional technology in which the amount of heat is not taken into account, and the boiling efficiency is lowered due to an increase in the temperature of hot water returning to the hot water storage tank. May be a problem.

  This invention was made in order to solve the above problems, and it aims at providing the hot water storage type water heater which can suppress the deterioration of boiling efficiency while ensuring the stability of hot water supply temperature. To do.

  The hot water storage type hot water heater according to the present invention heat-exchanges a hot water storage tank for storing hot water, heating means for heating the hot water stored in the hot water storage tank, and hot water supplied from the upper part of the hot water storage tank and hot water supply. Hot water supply heat exchanger, hot water supply pipe that leads hot water to the hot water terminal via the hot water heat exchanger, and hot water supply that leads from the upper part of the hot water tank to the lower part of the hot water tank via the hot water heat exchanger A hot water supply source, a hot water supply heat source pump that circulates hot water in the hot water supply heat source pipe, a hot water supply flow rate sensor that detects a flow rate of hot water flowing through the water supply pipe, and a hot water supply that supplies hot water to the hot water supply terminal A controller that controls the output of the hot water supply heat source pump in operation, and the control unit has a heat source side flow rate that is a flow rate of hot water flowing through the hot water supply heat source line when the water supply side flow rate is greater than or equal to a flow rate threshold value. Hot water supply heat so that it becomes more than flow rate Controlling the output of the pump, when the feed water side flow rate is less than the flow rate threshold value is used to control the output of the hot water supply heat source pump as the heat source-side flow rate is smaller than the feed water side flow.

  According to the hot water storage type hot water heater of the present invention, it is possible to provide a hot water storage type hot water heater capable of ensuring the stability of the hot water supply temperature and suppressing the deterioration of the boiling efficiency.

It is a block diagram which shows the hot water storage type water heater of Embodiment 1 of this invention. It is a circuit block diagram at the time of the boiling operation of the hot water storage type hot water heater which concerns on Embodiment 1 of this invention. It is a circuit block diagram at the time of the hot water supply operation of the hot water storage type hot water heater according to Embodiment 1 of the present invention. It is a figure which shows the change of the heat source side flow volume Fl with respect to the water supply side flow volume Fk, and the change of hot water supply temperature. It is a figure which shows the change of the heat source side flow volume Fl with respect to the feed water temperature Ti, and the change of hot water supply temperature.

  Embodiments of the present invention will be described below with reference to the drawings. In addition, the same code | symbol is attached | subjected to the element which is common in each figure, and the overlapping description is abbreviate | omitted.

Embodiment 1 FIG.
FIG. 1 is a configuration diagram of a hot water storage type hot water supply apparatus according to Embodiment 1 of the present invention. The hot water storage type water heater 35 includes a tank unit 33, an HP unit 7 that uses a heat pump cycle, and a remote controller 44 for performing an operation operation and setting value changing operation. The HP unit 7 and the tank unit 33 are connected to each other via an HP outgoing pipe 14, an HP return pipe 15, and an electric wiring (not shown). A control unit 36 is built in the tank unit 33. Operations of various valves, pumps, and the like provided in the tank unit 33 and the HP unit 7 are controlled by a control unit 36 electrically connected thereto. The control unit 36 and the remote controller 44 are connected so that mutual communication is possible. Although not shown, the remote controller 44 includes a display unit that displays information such as the state of the hot water storage water heater 35, an operation unit such as a switch operated by the user, a speaker, a microphone, and the like.

  The HP unit 7 functions as a heating means for heating the low-temperature water led from the hot water storage tank 8 provided in the tank unit 33. The HP unit 7 connects the compressor 1, the water refrigerant heat exchanger 3, the expansion valve 4, and the air heat exchanger 6 in a ring shape with a refrigerant pipe 5 to constitute a heat pump cycle. The water-refrigerant heat exchanger 3 is for exchanging heat between the refrigerant flowing through the refrigerant pipe 5 and the low-temperature water led from the tank unit 33.

  The tank unit 33 incorporates the following piping and various parts. The hot water storage tank 8 is for storing hot water. Water supplied from a water source such as water is introduced into the tank unit 33 through the first water supply pipe 9a. A water inlet 8a provided at the lower part of the hot water storage tank 8 is connected to the first water supply pipe 9a via a third water supply pipe 9c. A pressure reducing valve 31 is provided in the middle of the third water supply pipe 9c. The water supplied from the first water supply pipe 9 a to the third water supply pipe 9 c is adjusted to a specified pressure by the pressure reducing valve 31 and then flows into the hot water storage tank 8.

  One end of a water outlet port pipe 10 is connected to a water outlet port 8 b provided in the lower part of the hot water storage tank 8. The other end of the water outlet port pipe 10 is connected to the suction side of the heat source pump 12. The discharge side of the heat source pump 12 is connected to the inlet side of the HP unit 7 via the HP outgoing pipe 14. The tank unit 33 has a built-in three-way valve 18. The three-way valve 18 is a flow path switching means having an a port through which hot water flows in and b and c ports through which hot water flows out. The a port of the three-way valve 18 is connected to the outlet side of the HP unit 7 via the HP return pipe 15. The b port of the three-way valve 18 is connected to a hot water inlet 8d provided in the upper part of the hot water storage tank 8 via a hot water supply pipe 13. The c port of the three-way valve 18 is connected via a bypass pipe 16 to a hot water inlet 8 c provided between the central part and the lower part of the hot water storage tank 8.

  Hot water heated using the HP unit 7 flows into the hot water storage tank 8 from the hot water inlet 8d through the HP return pipe 15 and the hot water supply pipe 13, and low temperature water flows through the third water supply pipe 9c to the water inlet 8a. Inflow from. As a result, hot water is stored in the hot water storage tank 8 so that a temperature difference occurs between the upper and lower portions. A plurality of hot water storage temperature sensors are attached to the surface of the hot water storage tank 8 at different heights. More specifically, a hot water storage temperature sensor 42 is attached to the upper part of the surface of the hot water storage tank 8, and a hot water storage temperature sensor 43 is attached to the lower part of the surface of the hot water storage tank 8. The amount of remaining hot water in the hot water storage tank 8 is grasped by detecting the temperature distribution of the hot water in the hot water storage tank 8 with these hot water storage temperature sensors 42 and 43. The control unit 36 controls the start and stop of the hot water boiling operation in the hot water storage tank 8 by the HP unit 7 based on the detected remaining hot water amount.

  The tank unit 33 incorporates a hot water supply heat exchanger 52. The secondary inlet of the hot water supply heat exchanger 52 is connected to the first water supply pipe 9a via the second water supply pipe 9b. The secondary outlet of the hot water supply heat exchanger 52 is connected to the hot water tap 34 via the hot water supply pipe 21. In the following description, the pipe that guides the water supply from the water source to the hot-water tap 34 through the first water supply pipe 9 a, the second water supply pipe 9 b, the hot water supply heat exchanger 52, and the hot water supply pipe 21 is referred to as the water supply pipe 9. Further, in the middle of the second water supply pipe 9b, a hot water supply flow rate sensor 49 for detecting a water supply side flow rate Fk, which is a flow rate of hot water flowing through the water supply pipe line 9, and the temperature of the water supply flowing through the second water supply pipe 9b. In order to detect a certain feed water temperature Ti, a feed water temperature sensor 53 arranged in the first feed water pipe 9a is arranged in the example of the drawing.

  The primary inlet of the hot water supply heat exchanger 52 is connected to a hot water outlet 8e provided in the upper part of the hot water storage tank 8 via a heat source introduction pipe 46a. The primary outlet of the hot water supply heat exchanger 52 is connected to a hot water inlet 8f provided at the lower part of the hot water storage tank 8 via a heat source outlet pipe 46b. In the following description, the hot water in the hot water storage tank 8 led out from the hot water outlet 8e is reintroduced into the hot water storage tank 8 from the hot water inlet 8f via the heat source introduction pipe 46a, the hot water supply heat exchanger 52 and the heat source outlet pipe 46b. The line to be returned is referred to as a hot water supply heat source line 46. A hot water supply heat source pump 48 for circulating hot water in the hot water supply heat source pipe 46 is disposed in the middle of the heat source outlet pipe 46b. Further, a hot water supply heat source flow rate sensor 50 for detecting a hot water supply heat source flow rate Fl, which is a flow rate of hot water flowing through the hot water supply heat source pipeline 46, is disposed in the middle of the heat source outlet pipe 46b. The hot water discharged from the hot-water tap 34 is supplied to a mixing tap 51 such as a faucet that is a hot-water supply terminal, and is mixed with low-temperature tap water and used by the user.

  Next, the operation of the hot water storage type water heater according to the present embodiment will be described. FIG. 2 is a circuit configuration diagram of the hot water storage type water heater according to Embodiment 1 of the present invention at the time of boiling operation. The boiling operation referred to here is an operation in which hot water heated using the HP unit 7 is stored in the hot water storage tank 8. During the heating operation, the three-way valve 18 is controlled so that the a port and the b port communicate with each other and the c port is closed. Thereby, the HP return pipe 15 and the hot water supply pipe 13 communicate with each other, and the bypass pipe 16 side is closed, and the flow path to the hot water inlet 8c of the hot water storage tank 8 is blocked.

  The boiling operation is executed by starting the operation of the heat source pump 12 and the HP unit 7 in a state where the three-way valve 18 is controlled as described above. As a result, the low temperature water flowing out from the water outlet 8b of the hot water storage tank 8 is guided to the HP unit 7 via the water outlet port 10, the heat source pump 12, and the HP outgoing pipe 14, and in the water refrigerant heat exchanger 3. After being heated to high temperature hot water, it flows into the hot water storage tank 8 from the hot water inlet 8d of the hot water storage tank 8 through the HP return pipe 15, the three-way valve 18 and the hot water supply pipe 13, and is stored therein. By performing such a boiling operation, high temperature water is stored from the upper layer inside the hot water storage tank 8, and the high temperature water layer gradually becomes thicker.

  Further, in the hot water storage type hot water supply apparatus according to the present embodiment, a hot water supply operation for heating the water supplied from the water source is performed using the heat source of the high temperature water stored in the hot water storage tank 8 by the above-described boiling operation. . FIG. 3 is a circuit configuration diagram of the hot water storage type hot water supply apparatus according to Embodiment 1 of the present invention during a hot water supply operation. The hot water supply operation is executed by starting the operation of the hot water supply heat source pump 48 in response to the opening of the faucet or the like. As a result, the hot water stored in the upper part of the hot water storage tank 8 is introduced from the hot water outlet 8e to the primary side of the hot water supply heat exchanger 52 via the heat source introduction pipe 46a. At this time, the low temperature water flowing through the second water supply pipe 9 b is introduced to the secondary side of the hot water supply heat exchanger 52. The introduced low temperature water is heated by heat exchange with the primary high temperature hot water in the hot water supply heat exchanger 52 to become high temperature hot water. The water supply after becoming hot water is supplied to the hot water tap 34 via the hot water supply pipe 21. By performing such a hot water supply operation, hot water is continuously discharged from the mixing tap 51 such as a faucet. In the following description, the temperature of the water supplied from the hot water supply heat exchanger 52 is referred to as a hot water supply temperature.

  When the hot water supply operation is started in the hot water storage type water heater according to the present embodiment, the control unit 36 detects the water supply side flow rate Fk detected by the hot water supply flow rate sensor 49 (that is, the secondary side flow rate of the hot water supply heat exchanger 52). The target value setting means for setting the target flow rate Ftgt of the heat source side flow rate Fl, which is the primary flow rate of the hot water supply heat exchanger 52, is executed. And the control part 36 performs the pump control means which feedback-controls the output of the hot water supply heat source pump 48 so that the heat source side flow Fl detected by the hot water supply heat source flow sensor 50 becomes the target flow Ftgt. In the feedback control, the input voltage Vp of the hot water supply heat source pump 48 is controlled by, for example, PID (Proportional Integral Derivative) control.

  The hot water storage type water heater of the present embodiment is characterized by a configuration for setting the target flow rate Ftgt. FIG. 4 is a diagram illustrating a change in the heat source side flow rate Fl and a change in the hot water supply temperature with respect to the water supply side flow rate Fk. The dotted line in this figure indicates changes in the heat source side flow rate Fl and hot water temperature when Fl = Fk, and the solid line in the figure indicates the heat source side flow rate Fl and hot water temperature when Fl = f (Fk). Each change is shown. Moreover, in this figure, the case where the hot water storage temperature of the hot water currently stored in the upper part of the hot water storage temperature Ti and the hot water storage tank 8 is constant is shown.

  When the target flow rate Ftgt is set to the water supply side flow rate Fk, the heat source side flow rate Fl is controlled to Fl = Fk as shown by the dotted line in the figure. In this case, the hot water supply temperature decreases as the water supply side flow rate Fk increases. This is because when the water supply side flow rate Fk becomes large, the amount of heat that passes through the hot water supply heat exchanger 52 without heat exchange increases. For this reason, the hot water supply temperature decreases as the water supply side flow rate Fk increases, and conversely, the temperature of the hot water returned from the hot water supply heat exchanger 52 to the hot water storage tank 8 increases. In such a case, not only a stable hot water supply temperature cannot be realized, but also a decrease in boiling efficiency becomes a problem.

  Therefore, in the hot water storage type water heater of the present embodiment, the target flow rate Ftgt is set so that Fl = f (Fk) is realized. Specifically, as shown by a solid line in FIG. 4, a function is used where Fl <Fk when the water supply side flow rate Fk is smaller than the flow rate threshold value, and Fl ≧ Fk when the water supply side flow rate Fk is greater than or equal to the flow rate threshold value. The target flow rate Ftgt is set. As the flow rate threshold of the water supply side flow rate Fk, the value of the water supply side flow rate Fk at which the hot water supply temperature becomes the target temperature when Fk = Fl is used. As a result, the hot water temperature can be lowered within the range of Fk <flow rate threshold and the hot water temperature can be raised within the range of Fk ≧ flow rate threshold. Therefore, even when the water supply side flow rate Fk changes, the hot water temperature is targeted. It is possible to achieve a stable hot water supply temperature close to the temperature.

  Next, a specific example of the control of the present embodiment described above will be described. For example, when the water supply side flow rate Fk is the maximum flow rate 20 L / min and control is performed with Fk = Fl, the hot water supply temperature gradually rises as the water supply side flow rate Fk falls below 20 L / min. However, if the flow rate serving as the flow rate threshold is 20 L / min, Fl <Fk when the water supply side flow rate Fk is less than 20 L / min, and Fl = Fk when the water supply side flow rate Fk is 20 L / min, Fk = Fl. Compared with the case where the control is carried out, the hot water supply temperature decreases in any flow rate region. For this reason, the hot water supply temperature can be made constant at the hot water supply temperature at the maximum flow rate regardless of the water supply side flow rate Fk, and high temperature hot water supply at the low flow rate can be suppressed.

  As described above, according to the hot water storage type hot water supply apparatus of the present embodiment, the hot water supply temperature can be kept constant even when the water supply side flow rate Fk varies. Moreover, since the temperature rise of the hot water returned to the hot water storage tank 8 can be suppressed, it is possible to suppress a decrease in boiling efficiency.

  By the way, in the hot water storage type hot water heater of the above-described embodiment, the PID control of the heat source side flow rate Fl is executed, but the input voltage Vp of the hot water supply heat source pump 48 is controlled so that the heat source side flow rate Fl becomes the target flow rate Ftgt. Other feedback control may be used.

  Further, in the hot water storage type hot water heater of the above-described embodiment, the heat source side flow rate Fl is controlled using the function Fl = f (Fk). However, in the range where the water supply side flow rate Fk is smaller than the flow rate threshold, Fl <Fk. If the function is such that Fl ≧ Fk in the range where the water supply side flow rate Fk is equal to or higher than the flow rate threshold value, the configuration is not particularly limited. However, it is more preferable to use a function in which the hot water supply temperature is constant at the target temperature, and this makes it possible to effectively suppress fluctuations in the hot water supply temperature.

  Further, in the hot water storage type water heater of the above-described embodiment, the heat source side flow rate Fl is controlled using the function Fl = f (Fk), but the heat source side flow rate is such that the hot water supply temperature is constant at the target temperature. The heat source side flow rate Fl may be controlled using a map that defines the relationship between Fl and the water supply side flow rate Fk.

Embodiment 2. FIG.
Next, a second embodiment of the present invention will be described. The hot water storage type hot water heater of the second embodiment is characterized in that the target flow rate Ftgt of the heat source side flow rate Fl is set according to the feed water temperature Ti. FIG. 5 is a diagram showing a change in the heat source flow rate Fl and a change in the hot water supply temperature with respect to the water supply temperature Ti. The dotted line in this figure indicates changes in the heat source side flow rate Fl and hot water supply temperature when Fl = Fk, and the solid line in the drawing indicates the heat source side flow rate Fl and hot water supply temperature when Fl = g (Ti). Each change is shown. Moreover, in this figure, the case where the hot water storage temperature of the hot water stored in the upper part of the water supply side flow volume Fk and the hot water storage tank 8 is constant is shown.

  When the target flow rate Ftgt is set to the water supply side flow rate Fk, the heat source side flow rate Fl is controlled to Fl = Fk as shown by the dotted line in the figure. In this case, the hot water supply temperature rises as the water supply temperature Ti is higher, and there is a possibility that a stable hot water supply temperature cannot be realized.

  Therefore, in the hot water storage type water heater of the present embodiment, the target flow rate Ftgt is set so that Fl = g (Ti) is realized. Specifically, as shown by a solid line in FIG. 5, using a function in which Fl <Fk in the range where the feed water temperature Ti is equal to or higher than the temperature threshold and Fl ≧ Fk in the range where the feed water flow rate Fk is less than the temperature threshold, The target flow rate Ftgt is set. As the temperature threshold value of the feed water temperature Ti, the value of the feed water temperature Ti at which the hot water supply temperature becomes the target temperature at Fk = Fl is used. Thus, the hot water supply temperature can be increased in the range of Ti <temperature threshold and the hot water supply temperature can be decreased in the range of Ti ≧ threshold, so that the hot water supply temperature is set to the target temperature even when the feed water temperature Ti changes. Close and stable hot water supply temperature can be realized.

  Next, a specific example of the control of the present embodiment described above will be described. For example, when the heat source side flow rate is controlled regardless of the feed water temperature Ti, the hot water supply temperature gradually increases as the feed water temperature Ti rises. However, if the temperature threshold value of the feed water temperature Ti is set to 10 ° C. and the feed water temperature Ti is controlled to satisfy Fl <Fk when the feed water temperature Ti is 10 ° C. or more, the hot water supply temperature is lowered as compared with the case where Fk = Fl. Further, when the feed water temperature Ti is less than 10 ° C., the hot water supply temperature rises as compared with the case where the control is performed so that Fl ≧ Fk. For this reason, hot water supply temperature can be made constant irrespective of the water supply temperature Ti, and hot water supply can be suppressed at the time of high temperature water supply.

  As described above, according to the hot water storage type hot water supply apparatus of the present embodiment, the hot water supply temperature can be kept constant even when the water supply temperature Ti varies. Moreover, since the flow rate of the hot water returned to the hot water storage tank 8 can be suppressed, it is possible to suppress a decrease in the boiling efficiency due to the recirculation of useless medium temperature water.

  By the way, in the hot water storage type water heater of the above-described embodiment, the heat source side flow rate Fl is controlled using the function Fl = g (Ti), but the heat source side flow rate is such that the hot water supply temperature is constant at the target temperature. The heat-source-side flow rate Fl may be controlled using a map that defines the relationship between Fl and the feed water temperature Ti.

  In the hot water storage type water heater of the above-described embodiment, the target flow rate Ftgt of the heat source side flow rate Fl is set according to the feed water temperature Ti, but the target flow rate of the heat source side flow rate Fl according to the feed water side flow rate Fk. It is good also as combining with control of Embodiment 1 which sets Ftgt. In this case, for example, the target flow rate Ftgt can be set using a function of Fl = f (Fk) × g (Ti). This makes it possible to control the hot water supply temperature to the target value regardless of both the water supply side flow rate Fk and the water supply temperature Ti.

DESCRIPTION OF SYMBOLS 1 Compressor, 3 Water refrigerant heat exchanger, 4 Expansion valve, 5 Refrigerant circulation piping, 6 Air heat exchanger, 7 HP unit (heating means), 8 Hot water storage tank, 8a Water inlet, 8b Water outlet, 8c Inlet, 8d Hot water inlet, 8e Hot water outlet, 8f Hot water inlet, 9 Water supply pipe, 9a First water supply pipe, 9b Second water supply pipe, 9c Third water supply pipe, 10 Water outlet pipe, 12 Heat source pump , 13 Hot water supply piping, 14 HP outgoing piping, 15 HP return piping, 16 Bypass piping, 21 Hot water supply piping, 31 Pressure reducing valve, 33 Tank unit, 34 Hot water tap, 35 Hot water storage type hot water heater, 36 Control unit, 42, 43 Hot water storage Temperature sensor, 44 Remote control device, 46 Hot water supply heat source line, 46a Heat source introduction piping, 46b Heat source extraction piping, 48 Hot water supply heat source pump, 49 Hot water supply flow rate sensor, 50 Hot water supply heat source flow Sensor, 51 water mixing, heat exchanger 52 hot water, 53 water temperature sensor

Claims (9)

A hot water storage tank for storing hot water,
Heating means for heating hot water stored in the hot water storage tank;
A hot water supply heat exchanger for exchanging heat between hot water and hot water supplied from the upper part of the hot water storage tank;
A water supply conduit for guiding the hot water to the hot water terminal via the hot water heat exchanger;
A hot water supply heat source line leading from the upper part of the hot water storage tank to the lower part of the hot water storage tank via the hot water supply heat exchanger;
A hot water supply heat source pump for circulating hot water in the hot water supply heat source line;
A hot water supply flow rate sensor for detecting a water supply side flow rate which is a flow rate of the hot water supply flowing through the water supply pipeline;
A controller that controls the output of the hot water supply heat source pump in a hot water supply operation in which hot water is supplied to the hot water supply terminal, and
The control unit outputs the output of the hot water source heat source pump so that a heat source side flow rate, which is a flow rate of hot water flowing through the hot water source heat source pipe, becomes equal to or higher than the water supply side flow rate when the water supply side flow rate is equal to or higher than a flow rate threshold. A hot water storage type hot water heater that controls and controls the output of the hot water supply heat source pump so that the heat source side flow rate is smaller than the water supply side flow rate when the water supply side flow rate is smaller than the flow rate threshold.   The controller is configured to supply water when the heat source side flow rate is the same as the water supply side flow rate, and the temperature of the hot water supplied from the hot water heat exchanger to the water supply line is a target temperature. The hot water storage type hot water supply device according to claim 1, wherein a flow rate value is set as the flow rate threshold value. The controller is
Setting means for setting a target flow rate of the heat source side flow rate based on the water supply side flow rate;
Pump control means for controlling the output of the hot water supply heat source pump so that the heat source side flow rate becomes the target flow rate;
The hot water storage type hot water supply device according to claim 1 or claim 2 comprising: A hot water supply heat source flow sensor for detecting the heat source side flow rate;
The said pump control means is comprised so that feedback control may be performed to the output of the said hot water supply heat source pump so that the said heat source side flow volume detected by the said hot water supply heat source flow sensor may become the said target flow volume. Hot water storage water heater.   The hot water storage type hot water supply apparatus according to any one of claims 1, 3, and 4, wherein the control unit is configured to set a maximum flow rate of the water supply side flow rate as the flow rate threshold value. A water supply temperature sensor that detects a water supply temperature that is a temperature of the hot water supplied from the water supply pipe to the heat exchanger for hot water supply;
The control unit controls the output of the hot water supply heat source pump so that the heat source side flow rate is smaller than the water supply side flow rate when the feed water temperature is equal to or higher than a temperature threshold, and the water supply temperature is smaller than the temperature threshold. The hot water storage type hot water supply apparatus according to any one of claims 1 to 5, wherein an output of the hot water supply heat source pump is controlled so that the heat source side flow rate becomes equal to or higher than the water supply side flow rate.   The controller is configured to supply water temperature when the heat source side flow rate is the same as the water supply side flow rate and the temperature of the hot water supplied from the hot water heat exchanger to the water supply line is a target temperature. The hot water storage type hot water supply device according to claim 6, wherein the value is set as the temperature threshold value. A hot water storage tank for storing hot water,
Heating means for heating hot water stored in the hot water storage tank;
A hot water supply heat exchanger for exchanging heat between hot water and hot water supplied from the upper part of the hot water storage tank;
A water supply conduit for guiding the hot water to the hot water terminal via the hot water heat exchanger;
A hot water supply heat source line leading from the upper part of the hot water storage tank to the lower part of the hot water storage tank via the hot water supply heat exchanger;
A hot water supply heat source pump for circulating hot water in the hot water supply heat source line;
A hot water supply flow rate sensor for detecting a water supply side flow rate which is a flow rate of the hot water supply flowing through the water supply pipeline;
A feed water temperature sensor that detects a feed water temperature that is a temperature of the hot water supplied from the feed water pipe to the heat exchanger for hot water supply;
A controller that controls the output of the hot water supply heat source pump in a hot water supply operation in which hot water is supplied to the hot water supply terminal, and
When the feed water temperature is equal to or higher than a temperature threshold, the control unit has a water supply side flow rate in which a heat source side flow rate that is a flow rate of hot water flowing through the hot water supply heat source pipeline is a flow rate of the hot water supply flowing through the water supply pipeline The output of the hot water supply heat source pump is controlled to be smaller, and the output of the hot water supply heat source pump is controlled so that the flow rate on the heat source side is equal to or higher than the flow rate on the supply water side when the feed water temperature is lower than the temperature threshold. Hot water storage water heater.   The controller is configured to supply water temperature when the heat source side flow rate is the same as the water supply side flow rate and the temperature of the hot water supplied from the hot water heat exchanger to the water supply line is a target temperature. The hot water storage type water heater according to claim 8, wherein the value is set as the temperature threshold value.

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