JP2022068972A - Hot water storage and supply system - Google Patents

Abstract

To provide a hot water storage and supply system capable of determining a heating capacity of an auxiliary heat source machine, and controlling hot water supply from a hot water storage tank according to the determined heating capacity.SOLUTION: A hot water storage and supply system (1) including a hot water storage unit (3) having a hot water storage tank (2) for storing hot water heated by a main heat source machine (5), and a combustion-type auxiliary heat source machine (4), and performing a reheating operation for heating the hot water supplied by the hot water storage unit (3) by the auxiliary heat source machine (4) and supplying the same to a hot water tap, when hot water for hot water supply of a hot water supply set temperature does not exist in the hot water storage tank (2), further includes a heating capacity determination function for determining a minimum heating capacity of the auxiliary heat source machine (4) by a hot water supply temperature at which the auxiliary heat source machine (4) starts/stops the combustion when the hot water supply temperature of the hot water storage unit (3) is changed.SELECTED DRAWING: Figure 2

Description

The present invention relates to a hot water storage hot water supply system that uses hot water stored by heating with a main heat source machine for hot water supply.

Conventionally, as a main heat source machine with high heating operation efficiency, for example, hot water heated by a heat pump type heat source machine is stored in a hot water storage tank, and hot water is mixed with hot water discharged from this hot water storage tank to adjust the hot water supply temperature. A hot water storage system that supplies hot water is widely used.

If the hot water storage tank does not have hot water at a temperature that allows hot water to be supplied at the set hot water supply temperature, the hot water discharged from the hot water tank is reheated and supplied by, for example, a combustion type heat source machine as an auxiliary heat source machine having a large heating capacity. In the reheating operation by this auxiliary heat source machine, the heating capacity is adjusted in order to heat the hot water discharged from the hot water storage tank to the hot water supply set temperature.

As for the heating capacity of the auxiliary heat source machine, the maximum heating capacity and the minimum heating capacity are predetermined. Therefore, when the hot water temperature of the hot water storage tank is lower than the hot water supply set temperature close to the hot water supply set temperature, the temperature may be higher than the hot water supply set temperature even if the heating is performed with the minimum heating capacity. Therefore, for example, as in Patent Documents 1 and 2, there is known a technique for preventing the reheating operation when the heating capacity required for heating hot water is equal to or less than the minimum heating capacity.

Japanese Unexamined Patent Publication No. 2011-257878 Japanese Unexamined Patent Publication No. 60-240948

However, if the reheating operation is not performed as in Patent Documents 1 and 2, the user may feel discomfort or distrust due to the hot water supply having a temperature lower than the hot water supply set temperature, which is not preferable. Therefore, hot water is supplied by mixing low-temperature clean water with hot water discharged from the hot water storage tank, supplying hot water whose temperature has been lowered to a predetermined temperature or lower to the auxiliary heat source machine, and performing a reheating operation with a heating capacity higher than the minimum heating capacity. I try to supply hot water at the set temperature.

Since the temperature of the hot water in the hot water storage tank is lowered before heating, the amount of heat in the hot water storage tank cannot be fully utilized, and the amount of heat in the auxiliary heat source machine increases. Therefore, it is required to perform the reheating operation by the auxiliary heat source machine while utilizing the heat amount of the hot water storage tank as much as possible by controlling the hot water discharge from the hot water storage tank according to the heating capacity of the auxiliary heat source machine.

However, the hot water storage system may use an existing combustion type heat source machine as an auxiliary heat source machine, and this auxiliary heat source machine may be configured by combining a main heat source machine and a hot water storage unit having a hot water storage tank, and the hot water storage unit assists. In some cases, it may not be possible to obtain information on the heating capacity of the auxiliary heat source unit by communicating with the heat source unit.

An object of the present invention is to provide a hot water storage hot water supply system capable of determining the heating capacity of an auxiliary heat source machine and controlling the hot water discharge from the hot water storage tank according to the determined heating capacity.

The hot water storage hot water supply system of the invention of claim 1 is provided with a hot water storage unit having a hot water storage tank for storing hot water heated by the main heat source machine and a combustion type auxiliary heat source machine, and can supply hot water at the hot water supply set temperature to the hot water storage tank. In a hot water storage system that performs a reheating operation in which hot water discharged by the hot water storage unit is heated by the auxiliary heat source machine and supplied to a hot water tap when there is no hot water, when the hot water temperature of the hot water storage unit is changed, the hot water storage unit is described. It is characterized by having a heating capacity determination function for determining the minimum heating capacity of the auxiliary heat source machine according to the hot water temperature at which the auxiliary heat source machine starts / stops combustion.

According to the above configuration, the minimum heating capacity of the auxiliary heat source machine can be determined by changing the hot water discharge temperature of the hot water storage unit. Therefore, it is not necessary to limit the auxiliary heat source machine to be combined with the hot water storage unit to the auxiliary heat source machine having a specific minimum heating capacity, so that the hot water storage hot water supply system can be easily constructed.

The hot water storage hot water supply system according to the second aspect of the present invention is characterized in that, in the first aspect of the present invention, the hot water discharge temperature of the hot water storage unit in the reheating operation is controlled according to the minimum heating capacity determined by the heating capacity determination function. It is supposed to be.
According to the above configuration, it is possible to control the hot water outlet temperature of the hot water storage unit according to the minimum heating capacity of the auxiliary heat source machine to supply hot water at the hot water supply set temperature. Therefore, the amount of heat generated by the auxiliary heat source machine can be reduced by utilizing the amount of heat in the hot water storage tank.

The hot water storage and hot water supply system of the third aspect of the present invention is characterized in that, in the first aspect of the present invention, the heating capacity determination function is executed at the time of a trial run.
According to the above configuration, since the minimum heating capacity of the auxiliary heat source machine is determined by the trial run at the time of constructing the hot water storage system, it is easy to control the hot water discharge temperature of the hot water storage unit according to the determined minimum heating capacity when using hot water supply. Hot water supply It is possible to supply hot water at the set temperature.

According to the hot water storage hot water supply system of the present invention, the heating capacity of the auxiliary heat source machine can be determined, and the hot water discharge of the hot water storage unit can be controlled according to the determined heating capacity.

It is explanatory drawing of the structure of the hot water storage hot water supply system which concerns on embodiment of this invention. It is a flowchart of the heating determination function which concerns on Example. It is explanatory drawing of the hot water outlet temperature of the hot water storage unit at the time of execution of the heating determination function which concerns on Example. It is a hot water discharge control table of the hot water storage unit which concerns on an Example.

Hereinafter, embodiments for carrying out the present invention will be described with reference to examples.

First, the configuration of the hot water storage and hot water supply system 1 of the present invention will be described with reference to FIG. The hot water storage system 1 includes a hot water storage unit 3 having a hot water storage tank 2 and an auxiliary heat source machine 4. The hot water storage unit 3 has, for example, a heat pump type heat source machine as the main heat source machine 5, and performs a hot water storage operation of storing hot water heated by the main heat source machine 5 in the hot water storage tank 2. The auxiliary heat source machine 4 is, for example, a combustion type heat source machine, and supplies hot water supplied from the hot water storage unit 3 to the hot water tap 6 with or without reheating.

At the lower part of the hot water storage tank 2, a main heat source machine going passage 8 provided with a pump 7 for supplying the hot water of the hot water storage tank 2 to the main heat source machine 5 is connected. A main heat source machine return passage 9 for supplying hot water heated by the main heat source machine 5 to the hot water storage tank 2 is connected to the upper part of the hot water storage tank 2. A switching valve 10 for switching the flow path of hot water is arranged in the middle of the main heat source machine return passage 9, and a return branch passage 9a branched from the main heat source machine return passage 9 by the switching valve 10 is a main heat source machine going passage. It is connected to the upstream portion of the pump 7 of 8.

A return temperature sensor 9b for detecting the temperature of the hot water heated by the main heat source machine 5 is disposed on the upstream side of the switching valve 10 of the main heat source machine return passage 9. For example, when the detection temperature of the return temperature sensor 9b immediately after the start of the main heat source machine 5 is low, the switching valve 10 is switched from the hot water storage tank 2 side to the return branch passage 9a side, and the hot water storage tank 2 is sufficiently heated. Circulate the hot water without returning it.

A water supply passage 11 for supplying tap water is connected to the bottom of the hot water storage tank 2 as shown by an arrow CW, and hot water for discharging the hot water of the hot water storage tank 2 to the outside of the hot water storage unit 3 is connected to the top of the hot water storage tank 2. The passage 12 is connected. The water supply branch passage 11a branched from the middle of the water supply passage 11 is connected to the mixing valve 14 arranged in the middle of the hot water outlet passage 12. A plurality of hot water storage temperature sensors 2a to 2d are arranged in the hot water storage tank 2, and can detect the temperature and the amount of hot water stored in the hot water storage tank 2.

The water supply passage 11 is provided with a water supply temperature sensor 11b that detects the temperature of the tap water supplied from the water supply passage 11 (water supply temperature). In the hot water discharge passage 12, a hot water flow rate sensor 12a for detecting the flow rate of hot water from the hot water storage unit 3, a hot water storage tank hot water temperature sensor 12b for detecting the temperature of hot water discharged from the hot water storage tank 2 (hot water storage tank hot water temperature), and a hot water storage tank 12 A hot water temperature sensor 12c for detecting the hot water temperature from the unit 3 is arranged.

The hot water outlet passage 12 of the hot water storage unit 3 and the water supply port 4a of the auxiliary heat source machine 4 are connected by a hot water passage 15. A hot water supply passage 16 connected to the hot water tap 6 is connected to the hot water supply port 4b of the auxiliary heat source machine 4. The hot water discharged from the hot water storage unit 3 is supplied to the hot water tap 6 via the auxiliary heat source machine 4, and is supplied from the hot water tap 6 as shown by the arrow HW.

The hot water storage unit 3 drives a pump 7 to circulate hot water between the hot water storage tank 2 and the main heat source machine 5, and controls a hot water storage operation for storing hot water heated by the main heat source machine 5 from the upper part of the hot water storage tank 2. It has a control unit 18. The control unit 18 is based on the hot water storage tank hot water outlet temperature detected by the hot water storage tank hot water temperature sensor 12b, the water supply temperature detected by the hot water supply temperature sensor 11b, and the hot water flow rate detected by the hot water flow rate sensor 12a. The mixing ratio in the mixing valve 14 is adjusted so that the temperature detected in 12c becomes, for example, a preset hot water supply set temperature or a predetermined temperature, and the hot water is discharged.

For example, a hot water storage unit operation terminal 19 for setting a hot water supply set temperature by a user is connected to the control unit 18. The hot water storage unit operation terminal 19 is also connected to the auxiliary heat source machine 4, receives a combustion signal output by the auxiliary heat source machine 4 during combustion, and the control unit 18 acquires the combustion state of the auxiliary heat source machine 4. The auxiliary heat source machine 4 may have, for example, an auxiliary heat source machine operation terminal (not shown) for setting a hot water supply set temperature by the user, and a hot water tap having a hot water supply set temperature set by the hot water storage unit operation terminal 19. Communication may be possible so that it can be supplied to 6.

Next, the heating capacity determination function of the auxiliary heat source machine 4 by the control unit 18 will be described with reference to FIG. 3 based on the flowchart of FIG. Si (i = 1, 2, ...) In the figure represents a step. During the trial run performed during the construction of the hot water storage and hot water supply system 1, the control unit 18 determines the heating capacity of the auxiliary heat source machine 4 by executing the heating capacity determination function. When the user uses hot water supply, the control unit 18 controls the hot water discharge temperature from the hot water storage unit 3 so that the heat amount of the hot water storage tank 2 can be used as effectively as possible based on the heating capacity determined in the trial run.

At the time of construction of the hot water storage and hot water supply system 1, for example, water filling and a trial run of the main heat source machine 5 are performed, and then the heating capacity determination function is executed. First, in S1, a preparatory operation is performed. In the preparatory operation, after confirming that more than the required amount of hot water is stored in the hot water storage tank 2 at a temperature equal to or higher than the hot water supply set temperature required for determining the heating capacity based on the detected temperatures of the hot water storage temperature sensors 2a to 2d, the hot water tap is used. Prompt to open 6. If there is no hot water required for determining the heating capacity, the hot water storage operation is performed, and after the hot water storage is completed, the hot water supply tap 6 is urged to open. The hot water supply set temperature is set to, for example, 40 ° C., but it can be set arbitrarily. When the hot water tap 6 is opened, the process proceeds to S2. For example, when a predetermined flow rate (for example, 10 L / min) is detected by the hot water flow rate sensor 12a, the process proceeds to S2.

In S2, by supplying clean water to the auxiliary heat source machine 4, combustion of the auxiliary heat source machine 4 is started and the process proceeds to S3. Combustion of the auxiliary heat source machine 4 is started according to the temperature and flow rate of the hot water supplied to the auxiliary heat source machine 4. The hot water storage unit 3 supplies tap water to the auxiliary heat source machine 4 by fully closing the hot water storage tank 2 side of the mixing valve 14 and fully opening the water supply branch passage 11a side (see time t0 in FIG. 3). The auxiliary heat source machine 4 starts combustion so that the clean water supplied from the hot water storage unit 3 can be heated to the set hot water supply set temperature, adjusts the heating capacity, and supplies the heated hot water to the hot water supply tap 6.

In S3, it is determined whether or not the combustion of the auxiliary heat source machine 4 has started. For example, if the combustion signal is received and the determination of S3 is Yes, the process proceeds to S4. Then, in S4, by adjusting the mixing valve 14 (see time t1 to t2 in FIG. 3), the temperature is lower than the hot water supply set temperature by α [° C.] (for example, α = 1) (hot water supply set temperature −α [° C.]). The hot water of No. 1 is supplied to the auxiliary heat source machine 4, and the process proceeds to S5.

In S5, it is determined whether or not the combustion of the auxiliary heat source machine 4 has stopped. When hot water having a hot water supply set temperature −α [° C.] is supplied to the auxiliary heat source machine 4, for example, if the received combustion signal is no longer received and the determination in S5 is Yes, the process proceeds to S6. Then, in S6, by adjusting the mixing valve 14 (see time t3 to t4 in FIG. 3), the temperature is lower than the hot water supply set temperature by β [° C.] (for example, β = 3) (hot water supply set temperature −β [° C.]). The hot water of No. 1 is supplied to the auxiliary heat source machine 4, and the process proceeds to S7.

In S7, it is determined whether or not the combustion of the auxiliary heat source machine 4 has started. When hot water of the hot water supply set temperature −β [° C.] is supplied to the auxiliary heat source machine 4, for example, a combustion signal is received, and if the determination of S7 is Yes, the process proceeds to S8. Then, in S8, it is determined that the auxiliary heat source machine 4 is the A type having the minimum heating capacity "small", and the process proceeds to S12.

If, for example, a combustion signal is not received within a predetermined time (between time t4 and time t5 in FIG. 3) and the determination in S7 is No, the process proceeds to S9. Then, in S9, it is determined that the auxiliary heat source machine 4 is a B type having a minimum heating capacity of "large", and the process proceeds to S12.

On the other hand, when the determination in S5 is No (for example, when the combustion signal is continuously received between the time t2 and the time t3 in FIG. 3 as a predetermined time), the process proceeds to S10. Then, in S10, the auxiliary heat source machine 4 determines that it is a C type that needs to lower the temperature of the hot water discharged from the hot water storage unit 3, and proceeds to S12.

If the determination in S3 is No (for example, when the combustion signal cannot be received), the process proceeds to S11, the combustion error is notified in S11, and the process proceeds to S12. For example, when fuel is not supplied, the combustion capacity of the auxiliary heat source machine 4 cannot be determined, so a combustion error is notified and the combustion capacity determination is stopped.

Finally, in S12, the end operation is performed to end the heating capacity determination. At the end operation, the water heater 6 is urged to close. The type of the determined auxiliary heat source machine 4 may be notified.

FIG. 4 is a hot water discharge control table that defines the hot water discharge control of the hot water storage unit 3 for each heating capacity type of the determined auxiliary heat source machine 4. Since the A-type auxiliary heat source machine 4 has a small minimum heating capacity, it is possible to heat hot water having a hot water supply set temperature −β [° C.], which is slightly lower than the hot water supply set temperature, to the hot water supply set temperature. Therefore, hot water of the hot water supply set temperature is discharged from the hot water storage unit 3 until the hot water of the hot water storage tank 2 runs out. When the temperature of hot water discharged from the hot water storage unit 3 begins to drop due to the hot water running out of the hot water storage tank 2, the auxiliary heat source machine 4 can reheat and supply hot water at the set hot water supply temperature, so that the hot water supply temperature does not fluctuate significantly. ..

Since the B-type auxiliary heat source machine 4 has a large minimum heating capacity, hot water of the hot water supply set temperature −β [° C.] cannot be heated to the hot water supply set temperature, and the hot water supply becomes higher than the hot water supply set temperature. Therefore, if the hot water in the hot water storage tank 2 can be adjusted to the hot water supply set temperature and the hot water can be supplied, the hot water in the hot water storage tank 2 is adjusted to the hot water supply set temperature and the hot water supply is started. Then, before the hot water in the hot water storage tank 2 runs out, for example, when the detection temperature of the hot water storage temperature sensor 2d at the uppermost stage of the hot water storage tank 2 drops to the hot water supply set temperature −β [° C.] or less, the hot water storage unit 3 is used. The hot water outlet temperature is lowered to a predetermined temperature or less, and the auxiliary heat source machine 4 reheats the hot water to supply the hot water at the set hot water supply temperature.

The predetermined temperature may be, for example, 5 ° C. lower than the set hot water supply set temperature, or may be 5 ° C. lower than, for example, the lowest configurable hot water supply set temperature. When the hot water runs out, the auxiliary heat source machine 4 has already heated and supplied the hot water, so that the heating by the auxiliary heat source machine 4 is not started and the hot water supply temperature is prevented from falling higher than the hot water supply set temperature, and the hot water supply is prevented. The temperature does not fluctuate significantly.

Even if the hot water outlet temperature of the hot water storage unit 3 is close to the hot water supply set temperature, the C-type auxiliary heat source machine 4 always burns at the time of hot water supply in which hot water flows in the auxiliary heat source machine 4. Therefore, the temperature of the hot water discharged from the hot water storage unit 3 is set to a predetermined low temperature so that the auxiliary heat source machine 4 can always adjust the hot water supply temperature to the hot water supply set temperature. Even if the hot water runs out, the auxiliary heat source machine 4 adjusts the heating capacity according to the temperature drop of the supplied hot water, so that the hot water supply temperature does not fluctuate significantly.

The operation and effect of the hot water storage and hot water supply system 1 of the above embodiment will be described.
The hot water storage hot water supply system 1 has a heating capacity determination function for determining the minimum heating capacity of the auxiliary heat source machine 4 based on the hot water temperature at which the auxiliary heat source machine 4 starts / stops combustion when the hot water discharge temperature of the hot water storage unit 3 is changed. ing. Since the minimum heating capacity of the auxiliary heat source machine 4 can be determined, it is not necessary to limit the auxiliary heat source machine 4 to be combined with the hot water storage unit 3 to the auxiliary heat source machine having a specific minimum heating capacity. Therefore, the hot water storage and hot water supply system 1 can be easily constructed not only when combined with the new auxiliary heat source machine 4 but also when the already installed combustion type heat source machine is combined as the auxiliary heat source machine 4.

Further, the hot water outlet temperature of the hot water storage unit 3 in the reheating operation is controlled according to the determined minimum heating capacity. As a result, the amount of heat stored in the hot water storage tank 2 can be utilized to reduce the amount of heat generated by the auxiliary heat source machine 4, and even if the hot water supply tank 2 runs out of hot water during hot water supply, fluctuations in the hot water supply temperature are suppressed. It is possible to supply hot water at the set temperature for hot water supply.

The heating capacity determination function is executed in a trial run at the time of construction of the hot water storage and hot water supply system 1, and determines the minimum heating capacity of the auxiliary heat source machine 4. Therefore, when using hot water supply, it is possible to control the hot water supply according to the determined minimum heating capacity, and it is possible to easily supply hot water at the hot water supply set temperature.

In addition, a person skilled in the art can carry out the embodiment in a form in which various modifications are added to the above embodiment without departing from the spirit of the present invention, and the present invention includes such modified embodiments.

1: Hot water storage hot water supply system 2: Hot water storage tank 3: Hot water storage unit 4: Auxiliary heat source machine 5: Main heat source machine 6: Hot water tap 7: Pump 8: Main heat source machine Outbound passage 9: Main heat source machine Return passage 9a: Return branch passage 10 : Switching valve 11: Water supply passage 11a: Water supply branch passage 11b: Water supply temperature sensor 12: Hot water supply passage 12a: Hot water flow sensor 12b: Hot water storage tank Hot water temperature sensor 12c: Hot water temperature sensor 14: Mixing valve 15: Hot water passage 16: Hot water supply passage 18: Control unit 19: Hot water storage unit operation terminal

Claims (3)

The hot water storage unit is equipped with a hot water storage unit having a hot water storage tank for storing hot water heated by the main heat source machine, and a combustion type auxiliary heat source machine. In a hot water storage hot water supply system that performs a reheating operation in which hot water is heated by the auxiliary heat source machine and supplied to a hot water tap.
It is characterized by having a heating capacity determination function for determining the minimum heating capacity of the auxiliary heat source machine according to the hot water temperature at which the auxiliary heat source machine starts / stops combustion when the hot water discharge temperature of the hot water storage unit is changed. Hot water storage and hot water supply system. The hot water storage system according to claim 1, wherein the hot water discharge temperature of the hot water storage unit in the reheating operation is controlled according to the minimum heating capacity determined by the heating capacity determination function. The hot water storage and hot water supply system according to claim 1, wherein the heating capacity determination function is executed at the time of a trial run.

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