JP2023075363A - Hot water supply method, hot water supply system and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To continue stable hot water supply by preventing fluctuation of a hot water supply temperature even when heat storage in a hot water storage tank runs short.

SOLUTION: A hot water supply method using a hot water storage tank (10) includes steps of: mixing supply water with hot water in the hot water storage tank; detecting a temperature of the mixed water; heating the mixed water by auxiliary heating means (water heater 8); and in the case where a hot water supply required temperature, a threshold temperature for determining a heat storage state, a first set temperature that is lower than the threshold temperature and higher than the hot water supply required temperature, a second set temperature that is lower than the first set temperature and higher than the hot water supply required temperature and an operation start temperature for operating the auxiliary heating means are set, controlling a temperature of the mixed water to the first set temperature if the heat storage state is the threshold temperature or higher, controlling the temperature of the mixed water to the second set temperature if the heat storage state is lower than the threshold temperature and equal to or higher than the hot water supply required temperature, and operating the auxiliary heating means when the temperature of the mixed water is lowered to the operation start temperature.

SELECTED DRAWING: Figure 1

COPYRIGHT: (C)2023,JPO&INPIT

Description

The present invention relates to a hybrid hot water supply technology that uses, for example, a hot water storage unit as a heat storage source, a heat pump as a heat supply source, and a water heater as a hot water heating means.

A hybrid hot water supply system has been put into practical use, in which hot water heated by heat from an external heat source such as a heat pump is stored to store the stored hot water, and the stored hot water is supplied in response to a request for hot water supply. there is

In a hot water supply system that utilizes such heat-stored hot water to supply hot water and that hot water is heated by a heating device and supplied, the hot water discharged from the hot water storage tank is mixed with a predetermined amount of tap water to lower the temperature, and a mixing unit is provided. There is also a type in which water is mixed with hot water in a mixing unit to adjust the temperature and then discharged to the hot water outlet side. (For example, Patent Document 1 and Patent Document 2).

JP-A-2005-42965 JP 2007-315749 A

By the way, in a hot water supply system that supplies hot water using hot water stored in a hot water storage tank, the heat stored in the hot water storage tank is consumed as the demand for hot water supply increases. In the hot water supply system, when the heat in the hot water storage tank is consumed and hot water cannot be supplied to meet the hot water supply demand, a hot water supply device serving as an auxiliary heat source heats and supplies hot water. When the heat storage in the hot water storage tank is insufficient during hot water supply and auxiliary heating by the water heater is started, the heating speed by the combustion part cannot keep up with the time from ignition of the burner until the heating state stabilizes and the speed of hot water temperature decrease. However, there is a problem that the hot water supply temperature may drop temporarily.

In addition, when introducing a hybrid hot water system by installing a hot water tank unit, etc. in the hot water supply facility, or when replacing some of the equipment in the existing hybrid hot water system, the water heater and hot water tank unit may be manufactured by different manufacturers. be. Since different manufacturers have different operation specifications, it is difficult to interlock and integrate the contents of control, and control methods with different communication protocols make it impossible to perform integrated control and management with a common remote controller. Therefore, in order to control the combustion start timing of the water heater based on the monitoring result of the heat storage state in the hot water storage tank, a new control device that controls the entire hybrid hot water system will be added, and remote control devices for each device will be added. There is a problem that it is difficult to introduce the system, such as increasing the cost of the equipment and increasing the workload, such as by standardizing the control algorithm.
Patent Document 1 and Patent Document 2 do not disclose or suggest such a problem, and the configuration disclosed in Patent Document 1 and Patent Document 2 cannot solve such a problem.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to prevent fluctuations in the hot water supply temperature and to continue stable hot water supply even if the heat storage in the hot water storage tank is insufficient.

In order to achieve the above object, according to one aspect of the hot water supply method of the present invention, there is provided a hot water supply method using hot water stored in a hot water storage tank, wherein the hot water from the hot water storage tank is mixed in a mixing unit. a step of detecting the temperature of the mixed water obtained in the mixing section; a step of heating the mixed water supplied from the mixing section with auxiliary heating means; a required hot water supply temperature and a heat storage state of the hot water tank a first set temperature lower than the threshold temperature and higher than the required hot water supply temperature; a second set temperature lower than the first set temperature and higher than the required hot water supply temperature; When an operation start temperature for operation is set and the heat storage state is equal to or higher than the threshold temperature, the temperature of the mixed water is controlled to the first set temperature, and the heat storage state is less than the threshold temperature and the hot water supply and controlling the temperature of the mixed water to the second set temperature if it is equal to or higher than the required temperature, and operating the auxiliary heating means when the temperature of the mixed water drops to the operation start temperature.

In order to achieve the above object, according to one aspect of the hot water supply system of the present invention, there is provided a hot water supply system using hot water stored in a hot water storage tank for supplying hot water, and a mixing unit for mixing the hot water from the hot water storage tank with water supply. a temperature sensor for detecting the temperature of the mixed water obtained in the mixing section; auxiliary heating means for heating the mixed water supplied from the mixing section; a required hot water supply temperature; a threshold temperature, a first set temperature lower than the threshold temperature and higher than the required hot water supply temperature, a second set temperature lower than the first set temperature and higher than the required hot water supply temperature, an operation of operating the auxiliary heating means When the start temperature is set and the heat storage state is equal to or higher than the threshold temperature, the temperature of the mixed water is controlled to the first set temperature, and the heat storage state is lower than the threshold temperature and is equal to or higher than the hot water supply request temperature. Then, the control unit controls the temperature of the mixed water to the second set temperature, and operates the auxiliary heating means when the temperature of the mixed water drops to the operation start temperature.

In order to achieve the above object, according to one aspect of the program of the present invention, there is provided a program to be executed by a computer, comprising a function of mixing hot water from a hot water storage tank with water in a mixing unit; a function of acquiring detection information from a temperature sensor that detects the temperature of the mixed water supplied from the mixing unit; a function of causing the auxiliary heating means to heat the mixed water supplied from the mixing unit; a threshold temperature to be determined, a first set temperature lower than the threshold temperature and higher than the required hot water supply temperature, a second set temperature lower than the first set temperature and higher than the required hot water supply temperature, operating the auxiliary heating means If the operation start temperature is set and the heat storage state is equal to or higher than the threshold temperature, the temperature of the mixed water is controlled to the first set temperature, the heat storage state is less than the threshold temperature, and the hot water supply request If it is above the temperature, the computer controls the temperature of the mixed water to the second set temperature, and operates the auxiliary heating means when the temperature of the mixed water drops to the operation start temperature. let it run.

ADVANTAGE OF THE INVENTION According to this invention, one of the following effects is acquired.

(1) By starting the water heater, which is an auxiliary heat source, before the heat storage in the hot water storage tank becomes insufficient, it is possible to suppress temperature fluctuations during hot water delivery.

(2) Even if the water heater, which is an auxiliary heat source, is started due to insufficient heat storage in the hot water tank during hot water supply, the hot water supply temperature does not drop. Reliability can be improved.

(3) By varying the set temperature that is adjusted by mixing hot water discharged from the hot water storage tank with low-temperature water, it is possible to adjust the timing of auxiliary heating without controlling the operation of the water heater.

(4) By setting the temperature of the hot water discharged from the mixing section of the hot water storage tank unit to a value higher than the required hot water supply temperature and within the ignition start temperature range of the water heater, the heating capacity when the water heater is started is increased. It is possible to reduce the influence of fluctuations and supply hot water according to the required temperature.

4 is a flowchart showing an example of hot water supply control according to the first embodiment; FIG. 2 is a diagram showing a configuration example of a hot water supply system according to a second embodiment; FIG. It is a figure which shows the structural example of a water heater. FIG. 4 is a diagram showing a configuration example of a controller of the hot water storage unit; It is a figure which shows the structural example of the control part of a water heater. 4 is a graph showing a state example of temperature change of hot water by the hot water supply system. 4 is a flowchart showing an example of hot water supply control; 4 is a flowchart showing an example of operation control of a water heater; FIG. 11 is a diagram showing a configuration example of a hot water supply system according to a third embodiment; FIG. 7 is a graph showing a comparative example of hot water supply process;

[First Embodiment]
FIG. 1 shows an example of hot water supply control according to the first embodiment. The processing content and processing procedure shown in FIG. 1 are examples, and the present invention is not limited to such content. This hot water supply control process is an example of the hot water supply method or program of the present invention.

This hot water supply process consists of storing hot water in the hot water storage unit 4 (S101), obtaining heat storage state information in the hot water storage tank 10 (S102), discharging hot water in the hot water storage tank (S103), and mixing the hot water discharged from the hot water storage tank 10 with water. It includes a process of mixing with the mixed water control valve 12, which is a part, and adjusting to the set temperature (S104), determination of the heat storage state (S105), and change of the set temperature in the mixing part (S106).

Hot water storage in hot water storage unit 4 (S101): Hot water is stored in hot water storage tank 10 of hot water storage unit 4 using heat pump 6 as a heat source. A heat pump 6 , which is an example of a heat source, is normally kept in a driven state, and hot water HW heated by the heat pump 6 is stored in a hot water storage tank 10 .

Acquisition of heat storage state information in hot water storage tank 10 (S102): The temperature of hot water at a predetermined height in hot water storage tank 10 is measured in order to determine whether hot water can be discharged at a temperature that meets the hot water supply request. The hot water storage tank 10 stores high-temperature hot water in the upper part, and performs hierarchical heat storage in which the temperature decreases as it goes down. Therefore, by measuring the temperature of the hot water at a predetermined height, it is possible to grasp the temperature distribution in the tank and the heat storage state such as the hot water supply capacity. In judging the heat storage state, for example, the temperature at one location in the hot water storage tank 10 may be detected, and the temperatures at a plurality of locations at different heights may be detected. By increasing the number of temperature detection positions, more detailed heat storage conditions can be grasped.
Hot water in the hot water storage tank is discharged (S103): When the water supply W flows through the water supply pipe 14 by opening the run 32, part of the water W flows into the bottom side of the hot water storage tank 10, and hot water is stored according to the inflow amount. High-temperature hot water HW on the upper layer side of the tank 10 flows into the hot water supply pipe 18 . The demand for hot water supply may be detected by a water flow sensor 40 installed in the water supply pipe 14, for example.
Hot water and water discharged from the hot water storage tank 10 are mixed by the mixed water control valve 12 and adjusted to the set temperature (S104): is mixed with the feed water W to generate hot water at the set temperature. At this time, the first set temperature is set in the mixed water control valve 12 as a control process for supplying hot water without operating the water heater 8 as the auxiliary heat source. The hot water HW that has passed through the mixed water control valve 12 passes through the hot water supply pipe 26, the water heater 8, and flows through the hot water supply pipes 28 and 30 to the hot water supply load. In this hot water supply process, for example, the temperature sensor 16-1 detects the temperature of the water supply, and the temperature sensor 16-2 detects the temperature of the hot water discharged from the hot water storage tank 10. The mixing ratio of water in the mixed water control valve 12 is calculated based on the set temperature. Then, by setting the degree of opening of the mixed water control valve 12 based on the calculated mixing ratio, the amount of hot water discharged from the hot water storage tank 10 is adjusted.
Determination of heat storage state (S105): When the hot water supply request continues, the heat storage state information in the hot water storage tank 10 is continuously collected, and whether or not the heat storage state in the hot water storage tank 10 is less than a preset threshold value is determined. Judgment The threshold value used for this judgment may be judged by whether or not there is hot water HW at a temperature at which hot water can be supplied in response to the hot water supply request through the hot water supply system 2 .
Change of set hot water outlet temperature (S106): In the hot water storage unit 4, the mixed water control valve 12 on the hot water outlet side of the hot water storage unit 4 is operated to start the auxiliary heat source before the amount of heat in the hot water storage tank 10 cannot meet the demand for hot water supply. The temperature of hot water to be generated is changed to the second set temperature. The changed second set temperature is, for example, a temperature higher than the temperature of hot water HW finally discharged from hot water supply system 2 and a temperature within a range where water heater 8 is ignited to start heat treatment.

<Effects of the first embodiment>
According to this first embodiment, one of the following effects can be obtained.
(1) By changing the set temperature of the hot water generated by the mixed water control valve 12 according to the heat storage state in the hot water storage tank 10 and starting the water heater, the heating process by the water heater 8 is in an unstable state. Even if there is, the temperature of the hot water finally discharged from the callan 32 is not changed.
(2) In the determination process of the heat storage state in the hot water storage tank, the hot water HW in the hot water storage tank 10 can be used to set the heat storage state in which the hot water HW in the hot water storage tank 10 can be used to discharge hot water as a threshold, thereby starting the water heater 8 without causing hot water shortage. It is possible to prevent the temperature of hot water from dropping or becoming unstable due to running out of hot water.
(3) By starting the auxiliary heating before the hot water in the hot water storage tank 10 runs out, the user does not feel uncomfortable due to a decrease in the outlet hot water temperature.
(4) The start-up control of the water heater 8, which is the auxiliary heat source, can be performed only by changing the set temperature for supplying hot water through the mixed water control valve 12 of the hot water storage unit 4, thus enhancing convenience.

[Second embodiment]
FIG. 2 shows a hot water supply system according to a second embodiment. The configuration shown in FIG. 2 is an example, and the present invention is not limited to such a configuration.

<About hot water supply system 2>
This hot water supply system 2 includes a hot water storage unit 4 , a heat pump 6 and a water heater 8 . For example, one water heater 8 may be provided, or a plurality of units may be operated in conjunction with each other at the same time or according to predetermined instruction control.
A water supply pipe 14 is connected to the bottom of the hot water storage tank 10 , and water supply W such as tap water is supplied to the lower layer side of the hot water storage tank 10 . On the water supply pipe 14, a temperature sensor 16-1 for detecting the inflow temperature (Tin) of the water supply W and a water flow sensor 40 for detecting the flow rate of the water supply W are installed.
In addition, the hot water supply system 2 includes, for example, a hot water supply pipe 28 for flowing hot water that has passed through the water heater 8, a hot water supply pipe 30 for flowing to the callan 32 side, and a water supply pipe 14 branched from the water supply pipe 14 to supply low-temperature water supply W to the callan 32. It has a supply pipe 34 . In the hot water supply system 2, high temperature hot water is supplied to the hot water outlet pipe 30 through the hot water storage unit 4 and the water heater 8, and is mixed with the low temperature water supply W in the callan 32 to generate hot water in response to the hot water supply request. A mixing method is used.

<About hot water storage unit 4>
A hot water supply pipe 18 for flowing high-temperature hot water HW in the hot water storage tank 10 is connected to the upper side of the hot water storage tank 10 . A temperature sensor 16-2 for detecting the hot water temperature (Ttnk) is provided on the hot water supply pipe 18. As shown in FIG.
Inside the hot water storage tank 10, a temperature sensor 16-3 for detecting the temperature of hot water (Tsto) installed at a predetermined height is provided. The temperature sensor 16-3 is an example of heat storage state information acquiring means for monitoring the heat storage state in the hot water storage tank based on the temperature of the hot water in the tank and the installed height. In the hot water storage tank 10 that is a hierarchical heat storage, the temperature of the hot water HW above the installation or temperature measurement position of the temperature sensor 16-3 is high. That is, when the temperature detected by the temperature sensor 16-3 satisfies the setting conditions for hot water supply, at least the volume above the installation position of the temperature sensor 16-3 is the amount of stored heat that allows hot water supply. Therefore, when the temperature detected by the temperature sensor 16-3 no longer satisfies the set temperature condition for supplying hot water, it indicates that there is a high possibility that the stored heat for supplying hot water at the set temperature is insufficient.
Temperature information detected by each sensor is provided to a control section 49 that controls the hot water storage unit 4 .

Mixed water control valve 12 is an example of the mixing section of the present invention, and is installed between water supply pipe 14 and hot water supply pipe 18 . The mixed water control valve 12 includes a distribution valve 22 that branches a portion of the low-temperature water supply W flowing through the water supply pipe 14, and a bypass pipe 20 that bypasses the hot water storage tank 10 and flows the distributed water supply W to the hot water supply pipe 18 side. , the distributed feed water W is combined with the high-temperature hot water HW in the hot water supply pipe 18, and has a water control valve 24 for controlling the flow rate of the combined hot water HW. The mixing ratio of hot water HW and feed water W is determined by the degree of opening of distribution valve 22 . In the hot water supply control, for example, the amount of water supply W flowing through the water supply pipe 14 is detected by the water flow sensor 40, and based on the outlet temperature of the hot water HW in the hot water storage tank 10 and the set temperature set in the mixed water control valve 12, The opening degree of the distribution valve 22 may be calculated.
A hot water supply line 26 is connected to, for example, the mixed water control valve 12 in the hot water storage unit 4, and the hot water HW adjusted to the set temperature by the mixed water control valve 12 is supplied to the water heater 8 side. A temperature sensor 16-4 is installed in the hot water supply pipe 26 to detect the temperature of hot water discharged from the hot water storage unit 4 (=mixed temperature Tmix-tu). Then, the controller 49 adjusts the opening degree of the mixed water control valve 12 so that the outlet hot water temperature detected by the temperature sensor 16-4 becomes the set temperature.

The heat pump 6 is an example of a heat source that heats the hot water HW in the hot water storage tank 10 by electric heat, for example. Between the hot water storage tank 10 and the heat pump 6, there is provided a heating circulation path for circulating the hot water HW between the hot water storage tank 10 and the heat pump 6. - 特許庁This heat supply circuit includes a heat supply pipe 42 through which low-temperature hot water or feed water W stored in the lower part of the hot water storage tank 10 flows toward the heat pump 6, and a high-temperature hot water HW from the heat pump 6 to the upper part of the hot water storage tank 10. includes a heat return pipe 44 through which the Furthermore, the heat supply supply pipe 42 and the heat supply return pipe 44 have a bypass pipe 46 that bypasses the heat pump 6 .
A temperature sensor 16-5 for detecting the temperature of the hot water before being heated by the heat pump 6 or a circulation pump 48 for pumping the hot water into the heating circulation path is provided on the heat supply pipe 42, for example.
On the heat supply return pipe 44, for example, a temperature sensor 16-6 for detecting the temperature of the hot water after heating by the heat pump 6, and a switching valve 47 are provided. The switching valve 47 switches the flow of the high-temperature hot water HW from the bypass pipe 46 to the heating return pipe 44 when the low-temperature hot water or feed water W stored in the lower side of the hot-water storage tank 10 reaches the upper limit temperature.
The heat pump 6 has, for example, a circuit in which a heat medium circulates inside. Equipped with a compressor and an expansion valve, the temperature of the circulating heat medium rises through compression and expansion, and this heat is used to heat hot water. The heat pump 6 is always maintained in an operating state, and is independently operated to compensate for the heat amount of hot water in the hot water storage tank 10 in preparation for hot water supply demand. When the temperature of the water in the lower layer of the hot water storage tank 10 reaches the upper limit temperature, the operation of the heat pump 6 may be stopped based on the detected temperature of the hot water flowing through the heating order pipe.

In addition, the hot water storage unit 4 has a hot water storage tank remote controller 36 . The hot water storage tank remote controller 36 is an example of display means for setting conditions for the set temperature of hot water discharged through the mixed water control valve 12 of the hot water storage unit 4, heat storage status information in the hot water storage unit 4, and other information.

The control unit 49 receives information about the temperature detected by the temperature sensors 16-1, 16-2, 16-3, 16-4, 16-5, and 16-6 installed in the hot water storage unit 4 and the detected flow rate of the water flow sensor 40. is collected, and hot water supply control is performed in response to the hot water supply request. This hot water supply control includes, for example, opening degree control of distribution valve 22 and water regulation valve 24 . Furthermore, as the hot water supply control of the present invention, the control unit 49 determines heat storage state information from the temperature sensor 16-3 in the hot water storage tank 10, and if the heat storage state in the hot water storage tank 10 is less than the threshold, A process for lowering the set temperature of the hot water HW generated by the water control valve 12 is performed. The threshold value of the heat storage state is set, for example, to a temperature condition within a range in which hot water can be discharged at a temperature corresponding to the hot water supply request without auxiliary heating by the water heater 8 .

<About water heater 8>
FIG. 3 shows a configuration example of a water heater.
When the hot water HW discharged from the hot water storage unit 4 flows through the hot water supply pipe 26, the water heater 8 supplies the hot water by auxiliary heating when the temperature of the hot water does not satisfy the set temperature, and when the set temperature is satisfied. , and flows to the outlet pipe line 28 side.
This water heater 8 has a heat exchanger 50 , a burner 52 and a mixing control valve 54 .
The heat exchanger 50 is an example of means for exchanging heat generated by the burner 52 as a heat source with the hot water HW. The burner 52, for example, combusts fuel gas to produce hot flue gas and includes an electric heater or other heat generating means.
The mixing control valve 54 has a distribution valve 64, a bypass pipe 66, and a water regulation valve 68, and directs part or all of the hot water HW supplied from the water supply pipe 60 connected to the hot water supply pipe 26 to the bypass pipe 66 side. , and flows to the outlet pipe line 28 side.
On the water supply pipe 60 are a temperature sensor 16-7, a flow rate sensor 62 for detecting the flow rate of water supply, a temperature sensor 16-8 for detecting the temperature of hot water after heat exchange, and a temperature of hot water discharged from the water heater 8. It has a temperature sensor 16-9.
The water heater 8 also has a controller 70 for controlling hot water supply and a water heater remote control 38 .
The control unit 70 acquires, for example, temperature information detected by the temperature sensors 16-7, 16-8, and 16-9 and detected flow rate information of the flow rate sensor 62, and based on these detection information, performs combustion control of the burner 52, It performs opening degree control of the distribution valve 64 and the water regulation valve 68, and the like.

<Control section 49 of hot water storage unit 4>
FIG. 4 shows a configuration example of the controller of the hot water storage unit 4. As shown in FIG.
The control unit 49 is composed of a computer having a communication function, and has a processor 72, a memory unit 74, a system communication unit 76, and an input/output unit (I/O) 78, for example.
The processor 72 executes arithmetic processing of an OS (Operating System) and a hot water supply control program stored in the memory unit 74 . The memory unit 74 stores data necessary for hot water supply control in addition to the OS and control programs. Detected temperature information of 16-3 and 16-4 is stored. The memory unit 74 includes ROM (Read-Only Memory) and RAM (Random-Access Memory). A storage element such as a hard disk device or a nonvolatile memory for storing data is used for the memory unit 74 . The RAM constitutes a work area for information processing.

The system communication unit 76 is wirelessly or wiredly connected to the hot water storage tank remote control 36, and transmits and receives instruction information for the temperature setting of the mixed water control valve 12 and operation instruction information for the hot water storage unit 4. 4 operation status information is sent and received.
The I/O 78 acquires detection information from the water flow sensor 40 and the temperature sensors 16-1, 16-2, 16-3, and 16-4, and also transmits control information generated by the processor 72 to the distribution valve 22 and the water regulation valve. 24, etc.

<Control unit 70 of water heater 8>
FIG. 5 shows a configuration example of the control unit of the water heater 8. As shown in FIG.
The control unit 70 is composed of a computer, and has a processor 80, a memory unit 82, a communication unit 84, and an input/output unit (I/O) 86, for example.
Processor 80 executes arithmetic processing of an OS (Operating System) and a hot water supply control program stored in memory unit 82 . The memory unit 82 stores data necessary for hot water supply control in addition to the OS and control programs, and temperature sensors 16-7, 16-8, and 16 for detecting the temperature of hot water flowing through the water supply pipe 60 and the hot water discharge pipe 28. Detected temperature information of -9, flow rate information of hot water detected by the flow rate sensor 62, and the like are stored. The memory unit 82 includes ROM (Read-Only Memory) and RAM (Random-Access Memory). A storage element such as a hard disk device or a nonvolatile memory for storing data is used for the memory unit 74 . The RAM constitutes a work area for information processing.

The communication unit 84 is wirelessly or wiredly connected to, for example, the water heater remote controller 38 or a control unit of another water heater connected to the hot water supply system 2, and receives temperature information of a hot water supply request. 8 operating state information and the like.
The I/O 86 acquires detection information from the flow rate sensor 62 and the temperature sensors 16-7, 16-8, and 16-9, and also transmits control information generated by the processor 80 to the water control valve 68, the distribution valve 64, and the like. to send.

<Regarding the state of control by the hot water supply system>
FIG. 6 shows an example of change in temperature of hot water by the hot water supply system. Although an example of set temperatures for the hot water storage unit 4 and water heater 8 of the hot water supply system 2 is shown here, the present invention is not limited to such set conditions.
In this hot water supply system, for example, the callan temperature (Tout), which is the required hot water supply temperature (TempHW), is set to 40 [° C.], and the threshold of the temperature detected by the temperature sensor 16-3 is set as the threshold of the heat storage state in the hot water storage tank 10. P is 65[°C]. Also, the temperature of the hot water flowing through the hot water supply pipes 28 and 30 through the water heater 8 is set at 60 [°C]. Note that the temperature of the feed water W is assumed to be 15 [°C].
Concerning the state of heat storage in the hot water storage tank 10, as hot water continues to be discharged from the hot water storage tank 10 in response to a hot water supply request, heat is consumed over time, so the hot water storage tank temperature (Tsto) decreases. The mixed water control valve 12 adjusts the mixed amount of the feed water W according to the hot water storage tank temperature (Tsto), so that the mixed temperature (Tmix-tu) is set to Temp1=60 [° C.] as the first set temperature. is maintained. As a result, in the hot water supply system 2, the hot water HW that can meet the hot water supply request is discharged from the hot water storage unit 4, so that the hot water heater 8 is bypassed without being operated, and the hot water HW is discharged to the callan 32 side through the hot water discharge pipes 28 and 30. flush. In the callan 32, the hot water HW at the first set temperature (Temp1) and the water supply W are mixed and discharged.

Further, in the hot water supply system 2, when the hot water supply request continues and the hot water storage tank temperature (Tsto) drops to the threshold value P at time t1, the mixture temperature (Tmix-tu) is set to the mixed water control valve 12 as the second set temperature. Temp2 is lowered to 50[°C]. This second set temperature (Temp2) is a temperature higher than the required hot water supply temperature. Furthermore, this second set temperature (Temp2) is a temperature within the ignition start temperature range of the burner 52 mounted on the water heater 8 . This ignition start temperature is a threshold temperature at which the burner 52 is ignited according to the temperature of water or hot water flowing into the water heater 8, for example. The range is a temperature lower than the threshold temperature set as the ignition start temperature. That is, in this hot water supply system 2, hot water is supplied from the mixed water control valve 12 at a temperature that activates the water heater 8, which is the auxiliary heat source, when the hot water storage unit 4 is in a heat storage state capable of responding to a hot water supply request.
In the hot water storage unit 4, the mixed temperature (Tmix-tu) is lowered to Temp2 during time X1 from time t1 to time t2 due to the change in the set temperature. As a result, the temperature of the hot water flowing into the water heater 8 during the time X1 falls below the ignition temperature of the burner 52, and the burner 52 ignites. In the hot water supply system 2, as the mixture temperature (Tmix-tu) reaches the second set temperature (Temp2), the water heater outlet hot water temperature (Tmix-bb) detected by the temperature sensor 16-9 also decreases. At t3, the temperature is stabilized at the set temperature Temp2. At this time, since the second set temperature (Temp2) is higher than the requested hot water supply temperature, the curran temperature (Tout) does not change.
In the hot water supply system 2, for example, when the time X2 from the ignition of the burner 52 to t4 elapses, the auxiliary heating by the water heater 8 stabilizes, and the hot water outlet temperature (Tmix-bb) of the water heater is set to the first setting. It rises to the temperature (Temp1). After that, in the hot water supply system 2, even if the hot water storage tank temperature (Tsto) drops, the hot water outlet hot water temperature (Tmix-bb) of the hot water heater 8 is maintained at the first set temperature (Temp1) by auxiliary heating of the hot water heater 8. The callan temperature (Tout) can continue to maintain the required hot water supply temperature (TempHW).
At this time, the set temperature of the second set temperature (Temp2) is maintained in the mixed water control valve 12, and even if the hot water outlet temperature of the water heater (Tmix-bb) starts to rise, the second set temperature (Temp2) is maintained. to get out of the water.

<About hot water supply control>
FIG. 7 shows an example of hot water supply control processing of the hot water storage unit. The processing procedure and processing contents shown in FIG. 7 are examples, and the present invention is not limited to such a configuration. This hot water supply control is an example of the hot water supply method or program of the present invention.
In the hot water supply system 2, the hot water in the hot water storage tank 10 is discharged at the first set temperature (Temp1) set by the hot water storage tank remote control 36 by the hot water supply control of the hot water storage unit 4 (S201). At this time, since hot water having a temperature corresponding to the hot water supply request is being discharged from the hot water storage unit 4, the water heater 8 is bypassed and auxiliary heating is not performed. In the hot water storage unit 4, the temperature of the hot water in the hot water storage tank 10, the first set temperature, and the water supply temperature are used as described above to control the hot water supply, and the mixture ratio is calculated by the mixed water control valve 12 and the mixture is controlled. etc.
Further, on the water heater 8 side, for example, based on the detected temperature of the temperature sensor 16-7 installed in the water supply pipe 60 and the detected flow rate of the flow sensor 62, it may be determined whether or not to operate the water heater 8. .

As a result of discharging hot water from the hot water storage unit 4, it is monitored whether or not the hot water storage tank temperature (Tsto) is equal to or lower than the set temperature α of the hot water storage tank remote control 36, for example. This set temperature α is an example of the threshold value P of the heat storage state. If the temperature of the hot water in the hot water storage tank 10 is not equal to or lower than the set temperature α (NO in S202), that is, if hot water with a temperature higher than the set temperature α is stored, the controller 49 controls only the hot water storage unit 4 side. continue to supply hot water.
When the temperature of the hot water in the hot water storage tank 10 is equal to or lower than the set temperature α (YES in S202), the control unit 49 controls the mixed water control valve 12 to start auxiliary heating by the water heater 8. The mixed temperature (Tmix-tu) of water is discharged at the temperature β set in the hot water storage tank remote control 36 (S203). This temperature β is the second set temperature (Temp2), which is higher than the required hot water supply temperature and within the ignition start temperature range of the burner 52 installed in the water heater 8 .
In the hot water supply system 2, since the mixed temperature is lowered, the heat stored in the hot water storage unit 4 is used to preheat the water, and hot water is supplied by heating using the combustion exhaust gas of the water heater 8 (S204).

<Hot water supply control on the water heater 8 side>
FIG. 8 shows an example of control processing of the water heater. The processing content or processing procedure shown in FIG. 8 is an example.
When the water heater operation is started (S301), the controller 70 detects the incoming water temperature of the hot or cold water flowing through the water supply pipe 60 . The water heater operation includes, for example, an initialization process and a process for monitoring the presence or absence of hot water supply. If the temperature of the hot water is equal to or lower than the ignition temperature (minimum combustion capacity) of the water heater 8 (YES in S302), the burner 52 is ignited to start hot water heating (S303).

<Effects of Second Embodiment>
According to such a configuration, the following effects are obtained.
(1) By changing the set temperature of the hot water generated by the mixed water control valve 12 according to the heat storage state in the hot water storage tank 10 and starting the water heater, hot water can be supplied at the required hot water supply temperature.
(2) By starting the auxiliary heating by the water heater 8 in the heat storage state capable of responding to the hot water supply request, the hot water supply is not affected by the hot water supply temperature becoming unstable when the water heater 8 is started.
(3) By starting the auxiliary heating before the hot water in the hot water storage tank 10 runs out, the user does not feel uncomfortable due to a decrease in the outlet hot water temperature.
(4) The start-up control of the auxiliary heat source can be performed only by changing the set temperature at which hot water is discharged through the mixed water control valve 12 of the hot water storage unit 4, which enhances convenience.

[Third Embodiment]
FIG. 9 shows a configuration example of a hot water supply system 2 according to the third embodiment. In FIG. 9, the same parts as those in FIGS. 2, 3, etc. are denoted by the same reference numerals.
In the second embodiment, the case where auxiliary heating is performed by a single water heater 8 is shown, whereas in the hot water supply system 2 shown in FIG. . . 8-N are installed in parallel with the hot water supply pipe line 26 of the hot water storage unit 4 .
In such a configuration, the gas water heaters 8-1, 8-2, . The water heaters 8-1, 8-2, . 8-3, 8-4, . . . , 8-N may be selected. In addition, a plurality of gas water heaters 8-1, 8-2, . A follower may be set up that acts to

In the hot water supply control process, for example, the second set temperature set in the mixed water control valve 12 of the hot water storage unit 4 may be adjusted according to the number of gas water heaters set according to the flow rate of the hot water supply request. That is, the minimum combustion number of the water heater may vary depending on the number of gas water heaters 8-1, 8-2, 8-3, . . . 8-N to be operated. In the hot water supply system 2, for example, the hot water flows into the parallel gas water heaters 8-1, 8-2, and 8-3 in approximately the same amount. Therefore, when a large number of water heaters ready for operation start, it may be necessary to adjust the flow rate of hot water supplied from the hot water storage unit 4 . In this case, in the hot water storage unit 4, the threshold value P calculated according to the necessary flow rate and the temperature measurement position in the hot water storage tank 10 may be set for the heat storage state in the hot water storage tank 10 .

In addition, in the hot water supply system 2, for example, when the heat storage state becomes less than the threshold for hot water supply demand, only some of the plurality of gas water heaters 8-1 and 8-2 are started in advance, and the outlet hot water temperature is stabilized, a plurality of water heaters 8 for heating the required flow rate may be started.

<Effect of the third embodiment>
According to this third embodiment, any of the following effects can be obtained.
(1) By providing a plurality of gas water heaters 8-1, 8-2, . It is possible to realize a preheating water supply function with sufficient margin.
(2) By using a plurality of gas water heaters 8-1, 8-2, .

[Comparative example]

Next, a comparative example, which is a state of hot water supply processing in a conventional hot water supply system, will be described.
FIG. 10 shows a comparative example of a hot water supply system.
Such a hot water supply system has, for example, a hot water storage unit and a water heater as auxiliary heating means, as in the present application. In the hot water supply control, for example, as shown in FIG. 10, the heat storage state in the hot water storage tank is determined based on the hot water storage tank temperature (Tsto), and hot water is supplied based on the determination result. In the hot water supply system, as the hot water in the hot water storage tank is used, the temperature drops below the set temperature Temp1. The mixed temperature (Tmix-tu) discharged through the mixed water control valve 12 also decreases at about the same temperature as the hot water storage tank. As the mixture temperature (Tmix-tu) continues to decrease, it falls within the ignition temperature range of the water heater 8 at a predetermined time ta. Then, even after the predetermined time tb, the operation of the water heater 8 is not stabilized, and the water heater discharge hot water temperature (Tmix-bb) decreases, and becomes lower than the hot water supply request temperature TempHW.

When the operation of the water heater 8 is started and a predetermined time tc elapses, the operating state of the water heater 8 stabilizes, so that the water heater discharge hot water temperature (Tmix-bb) rises to the set temperature Temp1. It is possible to release hot water at

In this way, in a hot water supply system or a hot water storage unit in which the hot water in the hot water storage tank is supplementally heated by the water heater, if the hot water heater starts burning when the heat storage in the hot water storage tank decreases, the response of the auxiliary heating In addition to poor performance, only hot water at a temperature lower than the minimum required hot water outlet temperature can be generated. On the other hand, according to the hot water supply system and the hot water storage unit of the present invention, as shown in FIG. to start. As a result, even if there are factors such as instability of the operation at the start of the water heater 8, the hot water supply system 2 can supply hot water that can meet the hot water supply request, and the temperature of the hot water supplied from the callan can be prevented from lowering. .

[Other embodiments]
(1) In the above-described embodiment, the hot water storage tank 10 is single, but the present invention is not limited to this. In this hot water supply system 2, for example, a plurality of hot water storage tanks can be connected in series to store heat in a huge hot water storage capacity. In the hot water storage tank 10, the installation position of a temperature sensor 16-3 for monitoring the state of heat storage in the hot water storage tank 10 is set according to, for example, the distance to the hot water supply load corresponding to the hot water supply system 2 and the amount of hot water to be supplied. do it.

As described above, the most preferable embodiment and the like of the present invention have been described. The invention is not limited to the above description. Various modifications and changes are possible for those skilled in the art based on the gist of the invention described in the claims or disclosed in the detailed description. It goes without saying that such modifications and changes are included in the scope of the present invention.

The present invention lowers the set temperature of the hot water discharged from the hot water storage unit at the stage where the heat amount within the range that can meet the hot water supply request is stored in the heat storage tank, and starts the water heater as the auxiliary heat source. It is possible to supply hot water at a temperature corresponding to the hot water supply request without exerting the influence of the unstable state of the heat treatment during the startup period.

2 Hot water supply system 4 Hot water storage unit 6 Heat pump 8 Water heater 10 Hot water storage tank 12 Mixed water control valve 14, 60 Water supply pipe 16-1, 16-2, 16-3, 16-4, 16-5, 16-6, 16- 7, 16-8, 16-9 Temperature sensor 18, 26 Hot water supply pipe 20, 46, 66 Bypass pipe 22, 64 Distribution valve 24, 68 Water control valve 28, 30 Hot water discharge pipe 32 Callan 34 Water supply supply pipe 36 Hot water storage tank Remote controller 38 Water heater remote controller 40 Water flow sensor 42 Heat supply pipe 44 Heat supply return pipe 47 Switching valve 48 Circulation pump 49, 70 Control unit 50 Heat exchanger 52 Burner 54 Mixing control valve 62 Flow sensor 72, 80 Processor 74, 82 Memory Unit 76 System communication unit 78, 86 Input/output unit (I/O)
84 Communications Department

Claims (3)

A hot water supply method using hot water stored in a hot water storage tank,
mixing the hot water from the hot water storage tank with the water supply in a mixing unit;
a step of detecting the temperature of the mixed water obtained in the mixing section;
A step of heating the mixed water supplied from the mixing unit with auxiliary heating means;
a hot water supply request temperature, a threshold temperature for determining the heat storage state of the hot water storage tank, a first set temperature lower than the threshold temperature and higher than the hot water supply request temperature, a first set temperature lower than the first set temperature and higher than the hot water supply request temperature 2, the operation start temperature for operating the auxiliary heating means is set, and if the heat storage state is equal to or higher than the threshold temperature, the temperature of the mixed water is controlled to the first set temperature, and the heat storage state is set. is less than the threshold temperature and equal to or higher than the hot water supply request temperature, the temperature of the mixed water is controlled to the second set temperature, and when the temperature of the mixed water drops to the operation start temperature, the auxiliary operating the heating means;
Hot water supply method, including. A hot water supply system using hot water stored in a hot water storage tank,
a mixing unit that mixes the hot water from the hot water storage tank with the water supply;
a temperature sensor that detects the temperature of mixed water obtained in the mixing unit;
Auxiliary heating means for heating the mixed water supplied from the mixing unit;
a hot water supply request temperature, a threshold temperature for determining the heat storage state of the hot water storage tank, a first set temperature lower than the threshold temperature and higher than the hot water supply request temperature, a first set temperature lower than the first set temperature and higher than the hot water supply request temperature 2, the operation start temperature for operating the auxiliary heating means is set, and if the heat storage state is equal to or higher than the threshold temperature, the temperature of the mixed water is controlled to the first set temperature, and the heat storage state is set. is less than the threshold temperature and equal to or higher than the hot water supply request temperature, the temperature of the mixed water is controlled to the second set temperature, and when the temperature of the mixed water drops to the operation start temperature, the auxiliary a control unit that operates the heating means;
hot water system, including; A program for a computer to execute,
A function to mix hot water from the hot water storage tank with the water supply in the mixing unit,
A function of acquiring detection information from a temperature sensor that detects the temperature of the mixed water obtained in the mixing unit;
a function of causing an auxiliary heating means to heat the mixed water supplied from the mixing unit;
a hot water supply request temperature, a threshold temperature for determining the heat storage state of the hot water storage tank, a first set temperature lower than the threshold temperature and higher than the hot water supply request temperature, a first set temperature lower than the first set temperature and higher than the hot water supply request temperature 2, the operation start temperature for operating the auxiliary heating means is set, and if the heat storage state is equal to or higher than the threshold temperature, the temperature of the mixed water is controlled to the first set temperature, and the heat storage state is set. is less than the threshold temperature and equal to or higher than the hot water supply request temperature, the temperature of the mixed water is controlled to the second set temperature, and when the temperature of the mixed water drops to the operation start temperature, the auxiliary a function to operate the heating means;
A program that causes the computer to execute

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