JP6094447B2 - Water heater - Google Patents

Description

  The present invention relates to a hot water storage type hot water supply device, and more particularly to a hot water supply device having a function of supplying hot water immediately after the start of hot water supply (immediate hot water function).

  As a prior art, for example, as described in Patent Document 1, a water heater having an immediate hot water function is known. In a conventional water heater, hot water is circulated through a hot water supply pipe by driving a circulation pump while hot water is stopped (during non-hot water supply), and at the start of hot water supply, the circulating hot water is immediately supplied from the hot water tap. It is configured.

JP 2008-151450 A

  In the prior art described above, the circulation pump is driven during non-hot water supply, and hot water is circulated through the hot water supply pipe. If this hot water is not used for hot water supply, it is returned to the hot water storage tank. However, in the prior art, the circulation flow rate of the hot water is adjusted so that the temperature of the hot water returned to the hot water storage tank is lower than the predetermined temperature. There is a problem that power consumption increases.

  The present invention has been made to solve the above-described problems, and provides a water heater capable of protecting the pump by shortening the operation time of the circulation pump while ensuring an immediate hot water function. With the goal.

The hot water supply apparatus according to the present invention is supplied to the hot water supply terminal from the hot water storage tank for storing hot water, the hot water supply pipe for supplying hot water from the hot water storage tank to the hot water supply terminal for supplying hot water, and the hot water supply pipe during non-hot water supply. A hot water return pipe for returning hot water to the hot water storage tank, a circulation pump capable of performing a circulating operation for circulating hot water between the hot water storage tank and the hot water supply terminal via the hot water supply pipe and the hot water return pipe, and circulation during non-hot water supply A control device for performing a circulation operation by intermittently operating the circulation pump by repeatedly starting and stopping the pump, and a return hot water temperature detecting means for detecting the temperature of the hot water flowing through the return hot water piping as a return hot water temperature, during execution of the circulation operation, a changing means for changing on the basis of the stop time of the circulating pump from the stop to the restarting the circulation pump Kaeyu temperature, an outside air temperature detecting means for detecting the outside air temperature, the For example, the control device is made as a structure for setting the rotational speed of the circulation pump during the execution of the circulation operation as the outside air temperature is high in the low speed.

  According to the present invention, during the circulation operation, the operation time of the circulation pump is required while maintaining the hot water flowing through the hot water supply pipe and the hot water return pipe at a temperature suitable for hot water supply by repeatedly starting and stopping the circulation pump. The pump stop time can be appropriately controlled so as to be minimized. Thereby, the operation time of the circulation pump can be shortened and the life of the pump can be extended while ensuring the function of the hot water. Moreover, the power consumption of the circulation pump can be suppressed and the operating efficiency of the water heater can be improved.

It is a whole block diagram which shows the structural example of the water heater by Embodiment 1 of this invention. 5 is a flowchart illustrating an example of control executed by a control device in Embodiment 1 of the present invention. It is a whole block diagram which shows the structural example of the water heater by Embodiment 2 of this invention.

Embodiment 1 FIG.
Hereinafter, the first embodiment of the present invention will be described with reference to FIGS. 1 and 2. In each drawing used in this specification, common elements are denoted by the same reference numerals, and redundant description is omitted. FIG. 1 is an overall configuration diagram showing a configuration example of a water heater according to Embodiment 1 of the present invention. As shown in this figure, the water heater includes a hot water storage unit 1 and a heat pump unit 20. First, the hot water storage unit 1 will be described. The hot water storage unit 1 is equipped with a hot water storage tank 2, a boiling forward piping 3, a boiling return piping 4, a water supply piping 5, a hot water supply piping 10, a hot water return piping 11, a circulation pump 12, and the like. Has been.

  The hot water storage tank 2 stores hot water used for hot water supply or the like. A boiling forward pipe 3 is connected to the lower side of the hot water tank 2, and a boiling return pipe 4 is connected to the upper side of the hot water tank 2. Has been. The boiling forward piping 3 supplies low-temperature water taken out from the lower side of the hot water storage tank 2 to the heat pump unit 20 when a boiling operation described later is performed. The boiling return pipe 4 returns the high-temperature water heated by the heat pump unit 20 to the upper side of the hot water storage tank 2.

  The boiling forward piping 3 is provided with a boiling pump (not shown) for circulating hot water between the hot water storage tank 2 and the heat pump unit 20 via the boiling forward piping 3 and the boiling return piping 4. . In addition, a water supply pipe 5 to which low-temperature water is supplied from a water source such as city water is connected to the lower side of the hot water storage tank 2, and when hot water is supplied from the hot water supply terminal 40, Low temperature water is supplied to the lower side. Thereby, in the hot water storage tank 2, the temperature stratification is formed so that the high temperature water stays on the upper side and the low temperature water stays on the lower side.

  The hot water supply pipe 10 is a pipe for supplying hot water to the hot water supply terminal 40 that supplies hot water, and connects the upper side of the hot water storage tank 2 and the hot water supply terminal 40. The hot water return pipe 11 is a pipe for returning the hot water supplied from the hot water supply pipe 10 to the hot water supply terminal 40 to the hot water storage tank 2 during non-hot water supply, and connects the hot water supply terminal 40 and the lower side of the hot water storage tank 2. . The circulation pump 12 is a pump for performing a circulation operation during non-hot water supply, that is, when the hot water supply terminal 40 is not operated, and is provided in the hot water supply pipe 10, for example. In the circulation operation, hot water is circulated between the hot water storage tank 2 and the hot water supply terminal 40 via the hot water supply pipe 10 and the hot water return pipe 11 by operating the circulation pump 12.

  The heat pump unit 20 is a heating device using a refrigeration cycle (heat pump cycle), and is configured by connecting a compressor, a water heating heat exchanger, an expansion valve, and an evaporator (not shown) in a ring shape by piping. The heat pump unit 20 heats (boils) hot water introduced from the lower side of the hot water storage tank 2 via the boiling forward piping 3 to generate high temperature water. This high temperature water is returned to the upper side of the hot water storage tank 2 through the boiling return pipe 4.

  Next, a control system of the water heater will be described. The water heater includes a sensor system including a return hot water temperature sensor 13 and an outside air temperature sensor 14, and a control device 30. First, the sensor system will be described. The return hot water temperature sensor 13 detects the temperature of hot water flowing through the return hot water pipe 11 as the return hot water temperature, and constitutes a specific example of the return hot water temperature detecting means. The outside air temperature sensor 14 is provided, for example, in the heat pump unit 20 and detects the outside air temperature, and constitutes a specific example of the outside air temperature detecting means.

  The control device 30 is constituted by a microcomputer having an arithmetic processing unit and a storage circuit, and the sensor system is connected to the input side thereof. Various actuators including the boiling pump, the circulation pump 12, the heat pump unit 20, and the like are connected to the output side of the control device 30. Further, the control device 30 is electrically connected to a remote controller (not shown) disposed in, for example, a bathroom or kitchen. The remote controller is operated by a user of the water heater to set the temperature of hot water supplied from the hot water supply terminal 40 and the like. In the following description, the temperature of the hot water supplied from the hot water supply terminal 40 is expressed as “hot water supply temperature”, and the target value of the hot water temperature set by the remote controller is expressed as “target hot water supply temperature”.

  The control device 30 controls the operating state of the water heater by driving the actuator based on the output of the sensor system, user settings, and the like. In addition, the control device 30 performs boiling operation, circulation operation, and variable stop time control described below.

(Boiling operation)
First, when the amount of remaining hot water in the hot water storage tank 2 decreases, a boiling operation is executed. In the boiling operation, hot water is circulated between the hot water storage tank 2 and the heat pump unit 20 via the boiling forward piping 3 and the boiling return piping 4 by driving the heat pump unit 20 and the boiling pump. Thereby, the low temperature water staying at the lower side of the hot water storage tank 2 flows into the heat pump unit 20 through the boiling forward piping 3, and this hot water is heated by the heat pump unit 20 to become high temperature water. Then, the high-temperature water that has flowed out of the heat pump unit 20 flows into the upper part of the hot water storage tank 2 through the boiling return pipe 4 and is stored in the hot water storage tank 2.

(Circulation operation)
When hot water is not supplied from the hot water supply terminal 40 (during non-hot water supply), the circulation operation is executed. In the circulation operation, the circulation pump 12 is intermittently operated by repeatedly starting and stopping the circulation pump 12. Thereby, the hot water in the hot water storage tank 2 circulates through the hot water supply pipe 10 and the hot water return pipe 11 at the position of the hot water supply terminal 40. That is, the hot water taken into the hot water supply pipe 10 from the upper side of the hot water storage tank 2 by the circulation pump 12 flows into the hot water return pipe 11 at the position of the hot water supply terminal 40, and the lower side of the hot water storage tank 2 through the hot water return pipe 11. Returned to As a result, since hot water is always present in the hot water supply pipe 10, when the hot water supply terminal 40 is operated, the hot water in the hot water supply pipe 10 is immediately supplied to the hot water supply terminal 40 to realize an immediate hot water function. Can do.

(Stop time variable control)
During the execution of the circulation operation, variable stop time control is performed to make the stop time (pump stop time) of the circulation pump 12 variable. In the variable stop time control, the stop time from when the circulating pump 12 is stopped to when the circulating pump 12 is restarted is changed based on the hot water temperature. More specifically, in the variable stop time control, first, when the circulation pump 12 is repeatedly started and stopped, the operation time of the circulation pump 12 from when the stopped circulation pump 12 is started to when it is stopped again ( The following will be noted). Then, while detecting the hot water temperature by the hot water temperature sensor 13, the lowest value of the hot water temperature during each operation time is obtained as the minimum hot water temperature.

  On the other hand, in the variable stop time control, a target temperature range corresponding to the target hot water supply temperature is set based on the target hot water supply temperature set by the user or the like. The target temperature range is set, for example, as a temperature range slightly lower than the target hot water supply temperature. To give a specific example, the range of the temperature T satisfying the target hot water supply temperature −4 ° C. ≧ T ≧ target hot water supply temperature −5 ° C. Set as In the present invention, the target temperature range may be set based on the target hot water supply temperature, and is not limited to the above specific example.

  In the stop time variable control, the next pump stop time is made longer than the previous pump stop time when the minimum return hot water temperature is out of the target temperature range to the high temperature side. Here, the next pump stop time is a stop time from when the circulating pump 12 currently in operation is stopped to when it is restarted, and the previous pump stop time is the previous stop of the circulating pump 12. It is the stop time from restart to restart. If the minimum hot water temperature is higher than the target temperature range, the temperature of the hot water flowing through the hot water supply pipe 10 can be maintained at or above the target hot water temperature even if the pump stop time is extended. That is, in this case, the power consumption and operation time of the circulation pump 12 can be suppressed by extending the pump stop time.

  On the other hand, when the minimum hot water return temperature is out of the target temperature range to the low temperature side, the next pump stop time is shortened from the previous pump stop time. In this case, since the hot water temperature in the hot water supply pipe 10 is at least partly lower than the target temperature, the pump stop time is shortened and the operation time of the circulation pump 12 is relatively extended, and the hot water supply tank 2 supplies the hot water supply pipe. The amount of hot water supplied to 10 is increased. Thereby, the hot water temperature in the hot water supply pipe 10 can be raised so that the minimum return hot water temperature is within the target temperature range, and the hot water temperature in the hot water supply pipe 10 is prevented from excessively decreasing during the circulation operation. Can do.

  Next, a specific example of control according to the present embodiment will be described with reference to FIG. FIG. 2 is a flowchart showing an example of control executed by the control device in Embodiment 1 of the present invention. In this figure, first, in step S1, the start of the circulation operation is determined, and in step S2, the circulation pump 12 is activated. At this time, the circulation pump 12 is activated for the first time (first time).

  Next, in step S3, first, a minimum hot water return temperature is calculated for the purpose of determining the next pump stop time. Then, it is determined whether or not the calculated minimum return hot water temperature is higher than the target temperature range. When this determination is established, the process proceeds to step S4, and the next pump stop time is extended from the previous pump stop time.

  In the first pump operation time after the start of the circulation operation, the hot water in the hot water supply pipe 10 or the hot water return pipe 11 may be cooled by natural heat dissipation. If the minimum return hot water temperature is detected in this state, a temperature lower than the actual minimum return hot water temperature may be detected. For this reason, it is preferable to perform the process of step S3, S4 mentioned above not in the pump operation time of the 1st time, but in the pump operation time after the 2nd time.

  On the other hand, when the determination in step S3 is not established, the process proceeds to step S5, and it is determined whether or not the minimum return hot water temperature is a temperature lower than the target temperature range. If the determination in step S5 is established, the next pump stop time is shortened from the previous pump stop time in step S6, and then the process proceeds to step S7. If the determination in step S5 is not established, the process proceeds to step S7 without executing the process in step S6. Note that it is preferable not to execute the processes of steps S5 and S6 during the first pump operation time as in the case of steps S3 and S4.

  Next, in step S7, it is determined whether the hot water temperature is higher than the required temperature. Here, the required temperature is set based on the target hot water supply temperature, for example, and may be set to a temperature equal to the target hot water supply temperature. If the determination in step S7 is not established, the return hot water temperature has not reached the target temperature, and the process waits until the determination in step 7 is established with the circulation pump 12 being operated. On the other hand, if the determination in step S7 is established, the return hot water temperature is maintained at the target temperature, so the process proceeds to step S8 and the circulation pump 12 is stopped. According to the process of step S8, the hot water temperature in the hot water supply pipe 10 can be maintained at the required temperature, and the hot water temperature can be prevented from being inadvertently increased beyond the required temperature.

  Next, in step S9, for example, a timer counter provided in the control device 30 is used to measure the time during which the circulation pump 12 is actually stopped (actual stop time). Further, while measuring the actual stop time, it is determined whether or not the actual stop time has exceeded the set value of the pump stop time set in steps S4 and S6. And when determination of step S9 is not materialized, it waits until the determination of step S9 is materialized in the state where the circulation pump 12 was stopped. On the other hand, when the determination in step S9 is established, the set pump stop time has elapsed, so the process returns to step S2 to restart the circulation pump 12.

  If steps S4 and S6 are not executed for some reason and there is no set value for the pump stop time, in the determination process of step S9, for example, the initial value of the pump stop time set in advance, A set value or the like is used as the current set value.

  As described above in detail, according to the present embodiment, during the circulation operation, the hot water flowing through the hot water supply pipe 10 and the hot water return pipe 11 is changed to a temperature suitable for hot water supply by repeatedly starting and stopping the circulation pump 12. While being held, the pump stop time can be appropriately controlled so that the operation time of the circulation pump 12 is minimized. Thereby, the operating time of the circulation pump 12 can be shortened and the lifetime of the said pump can be extended, ensuring an instant hot water function. Moreover, the power consumption of the circulation pump 12 can be suppressed and the operating efficiency of the water heater can be improved.

  In the first embodiment, steps S3, S4, S5 and S6 in FIG. 2 show a specific example of changing means.

Embodiment 2. FIG.
Next, a second embodiment of the present invention will be described with reference to FIG. FIG. 3 is an overall configuration diagram showing a configuration example of a water heater according to Embodiment 2 of the present invention. As shown in this figure, the water heater according to the present embodiment includes a hot water supply pipe 50, a water supply pipe 51, a mixing valve 52, and a water supply temperature sensor 53 in addition to the configuration described in the first embodiment.

  The hot water supply pipe 50 is a pipe for taking out high temperature water from the upper side of the hot water storage tank 2, and is connected to the upper side of the hot water storage tank. The hot water supply pipe 10 is connected to the upper side of the hot water storage tank 2 through the hot water supply pipe 50 and the mixing valve 52. The water supply pipe 51 supplies hot water from the hot water return pipe 11 to the mixing valve 52, and is branched from the hot water return pipe 11 and connected to the mixing valve 52. The mixing valve 52 mixes the hot water supplied from the hot water supply pipe 50 and the hot water supplied from the return hot water pipe 11 and supplies the mixed water of both to the hot water supply pipe 10.

  The mixing valve 52 is configured by an electromagnetically driven three-way valve or the like and is controlled by the control device 30 and has two inflow ports and one outflow port. One inflow port of the mixing valve 52 is connected to the upper side of the hot water storage tank 2 via the hot water piping 50, and the other inflow port is connected to the hot water return piping 11. The outflow port of the mixing valve 52 is connected to the hot water supply pipe 10. The feed water temperature sensor 53 detects the temperature of the water flowing through the feed water pipe 51 and outputs the detection result to the control device 30, and constitutes a specific example of the feed water temperature detecting means.

  In the present embodiment, during the circulation operation, the mixing valve 52 is controlled based on the returning hot water temperature detected by the returning hot water temperature sensor 13 and the temperature of water detected by the feed water temperature sensor 53, and the hot water generated by the mixing valve 52 is used. And change the mixing ratio of low temperature water. Thereby, the controller 30 adjusts the temperature of the hot water flowing through the hot water supply pipe 10 and the return hot water pipe 11 during non-hot water supply, and adjusts the temperature so that the temperature of the hot water becomes equal to the target hot water temperature set by a remote controller or the like. Control.

  In the present embodiment configured as described above, substantially the same effects as those of the first embodiment can be obtained. In addition, according to the present embodiment, the hot water flowing through the hot water supply pipe 10 and the hot water return pipe 11 can be adjusted to a desired temperature during the circulation operation. Therefore, at the time of hot water supply, hot water at a temperature preferred by the user can be supplied immediately, and convenience can be improved. Moreover, since the hot water flowing through the hot water return pipe 11 is the same as the hot water flowing through the water supply pipe 51, the function of the hot water temperature sensor 13 is realized by the feed water temperature sensor 53 and used as a substitute for the detected value of the hot water temperature sensor. it can.

  In the first and second embodiments, during the circulation operation, the outside air temperature sensor 14 may detect the outside air temperature, and the rotation speed of the circulation pump 12 may be set to a lower rotation speed as the outside air temperature increases. As a specific example, for example, when the outside air temperature is a high temperature of about 40 ° C. with an outside air temperature of about 25 ° C. as a reference, the rotation speed of the circulation pump 12 is controlled to a low rotation speed of about 1000 rpm. When the outside air temperature is a low temperature of about 0 ° C., the rotation speed of the circulation pump 12 is controlled to be higher than that at a high temperature, for example, about 4000 rpm.

  According to this control, when the hot water flowing through the hot water supply pipe 10 and the hot water return pipe 11 is difficult to cool during the circulation operation, the rotation speed of the circulation pump 12 can be suppressed low. Thereby, it is possible to suppress the circulation pump 12 from being driven at a rotational speed higher than necessary, and to extend the life of the pump. Note that the specific values of the temperature and the rotational speed in the above control are merely examples, and do not limit the present invention.

  Moreover, in this Embodiment, the heat pump unit 20 was illustrated as a heating apparatus which boils the hot water in the hot water storage tank 2. FIG. However, the present invention is not limited to this, and a heating device such as an electric heater or a boiler may be used.

DESCRIPTION OF SYMBOLS 1 Hot water storage unit, 2 Hot water storage tank, 3 Boiling return piping, 4 Boiling return piping, 5 Water supply piping, 10 Hot water supply piping, 11 Hot water piping, 12 Circulation pump, 13 Hot water temperature sensor (Returning water temperature detection means), 14 outside air temperature sensor (outside air temperature detection means), 20 heat pump unit, 30 control device, 40 hot water supply terminal, 50 hot water supply pipe, 51 water supply pipe, 52 mixing valve, 53 water supply temperature sensor (water supply temperature detection means)

Claims (3)

A hot water storage tank for storing hot water;
A hot water supply pipe for supplying hot water from the hot water storage tank to a hot water supply terminal for supplying hot water;
A hot water return pipe for returning hot water supplied from the hot water supply pipe to the hot water supply terminal during non-hot water supply to the hot water storage tank;
A circulation pump capable of performing a circulation operation for circulating hot water between the hot water storage tank and the hot water supply terminal via the hot water supply pipe and the hot water return pipe;
A controller for performing the circulation operation by intermittently operating the circulation pump by repeatedly starting and stopping the circulation pump during non-hot water supply; and
Return hot water temperature detecting means for detecting the temperature of hot water flowing through the return hot water pipe as the return hot water temperature;
During the execution of the circulation operation, changing means for changing a stop time from stopping the circulation pump to restarting the circulation pump based on the return hot water temperature;
Outside temperature detecting means for detecting outside temperature;
Equipped with a,
The said control apparatus is a water heater set as the structure which sets the rotation speed of the said circulation pump in execution of the said circulation operation to a low rotation speed, so that the said external temperature is high .   The changing means stops the stop when a minimum hot water temperature, which is a minimum value of the hot water temperature detected during operation of the circulation pump, is out of a target temperature range corresponding to the target hot water temperature. The time is extended from the previous stop time, and when the minimum return hot water temperature is out of the target temperature range to the low temperature side, the stop time is shortened from the previous stop time. The listed hot water heater. A hot water supply pipe connected to the upper side of the hot water storage tank in order to take out the hot water from the upper side of the hot water storage tank;
A water supply pipe connected in the middle of the hot water return pipe to take out hot water flowing through the hot water return pipe,
A mixing valve that mixes high-temperature water supplied from the hot water supply pipe with hot water supplied from the water supply pipe and supplies the mixed water of the two to the hot water supply pipe;
Water temperature detecting means for detecting the temperature of hot water flowing through the water supply pipe, and
The control device controls the mixing valve based on the detection results of the hot water temperature detection means and the feed water temperature detection means, so that the hot water storage tank and the hot water supply terminal are connected during the circulation operation. The water heater according to claim 1 or 2 , wherein the temperature of the circulating hot water is adjusted.

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