Hot water storage water heater system

Abstract

To provide a hot water storage water heater system capable of more properly heating by an auxiliary heat source machine and supplying the hot water.SOLUTION: A hot water storage water heater system (1) includes: a hot water storage unit (3) including a hot water storage tank (2); a main heat source machine (4) for storing hot water in the hot water storage tank; an auxiliary heat source machine (5) for supplying hot water in the hot water storage tank by heating it or without heating it; a hot water tapping passage (12) for connecting the hot water storage tank and the auxiliary heat source machine; detection means for hot water storage temperature; detection means for hot water tapping temperature in the hot water tapping passage and detection means for the hot water tapping flow rate; and control means for the hot water storage and hot water supply. In the case where it is determined that there is hot water at a temperature that can be supplied to the hot water storage unit without heating, the control means prohibits heating by the auxiliary heat source machine, and in the case where it is determined that there is no hot water in the hot water storage unit at a temperature that can be supplied without heating, it permits heating by the auxiliary heat source machine. At the time of hot water tapping from the hot water storage unit, based on the hot water storage temperature and the hot water tapping flow rate or the hot water storage temperature, the hot water tapping flow rate and the hot water tapping temperature, presence / absence of the hot water that can be supplied without heating in the hot water storage unit is determined.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a hot water supply system that heats water in a storage tank by a heat pump unit and uses the hot water stored in the storage tank for hot water supply.

Background Art

[0002] Conventionally, a hot water supply system that uses a heat pump unit with excellent operating efficiency as a main heat source machine, heats hot water with the main heat source machine and stores it in a storage tank, and uses the hot water in this storage tank for hot water supply has been widely used. For example, as in Patent Document 1, a combustion type auxiliary heat source machine is installed in a hot water supply passage for supplying hot water from the storage tank, and when the hot water temperature at the outlet of the storage tank is lower than the set temperature, it is heated by the auxiliary heat source machine, and when it is higher than the set temperature, a hot water supply system is known that controls so as not to be heated by the auxiliary heat source machine.

[0003] On the other hand, in the hot water supply system of Patent Document 2, when there is a regulated amount or more of hot water that can supply hot water at the set temperature in the storage tank, heating by the auxiliary heat source machine is prohibited and the temperature is adjusted to the set temperature for hot water supply. In this hot water supply system, when there is less than the regulated amount of hot water that can supply hot water at the set temperature in the storage tank, heating by the auxiliary heat source machine is permitted, and hot water adjusted to a temperature lower than the heating start temperature is heated by the auxiliary heat source machine, and hot water adjusted to the set temperature is supplied for hot water supply.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] When hot water supply is started with hot water at the set temperature in the hot water storage tank, Patent Document 1 supplies hot water without heating by the auxiliary heat source machine, and Patent Document 2 prohibits heating by the auxiliary heat source machine and supplies hot water from the hot water in the hot water storage tank. Then, when there is no hot water at the set temperature for hot water supply from the hot water storage tank during hot water supply, heating is performed by the auxiliary heat source machine to supply hot water.

[0006] However, the hot water adjusted to the set temperature between the hot water storage tank and the auxiliary heat source machine is heated by the auxiliary heat source machine, which may prevent hot water supply at a stable temperature and reduce the operating efficiency of the hot water storage and supply system, which is not preferable. Therefore, an object of the present invention is to provide a hot water storage and supply system that can be appropriately heated by an auxiliary heat source machine.

Means for Solving the Problems

[0007] The hot water storage and supply system of the invention according to claim 1 includes a hot water storage unit having a hot water storage tank for storing hot water, a main heat source machine for heating the hot water in the hot water storage tank and storing the hot water in the hot water storage tank, an auxiliary heat source machine for heating or not heating the hot water in the hot water storage tank to supply hot water, a hot water outlet passage connecting the hot water storage tank and the auxiliary heat source machine, a hot water storage temperature detection means for detecting the hot water storage temperature of the hot water in the hot water storage tank, a hot water outlet temperature detection means for detecting the hot water outlet temperature of the hot water in the hot water outlet passage, a hot water outlet flow rate detection means for detecting the hot water outlet flow rate of the hot water in the hot water outlet passage, and a control means for controlling hot water storage and supply. When the control means determines that there is hot water at a temperature at which hot water can be supplied without heating in the hot water storage unit, heating by the auxiliary heat source machine is prohibited, and when it is determined that there is no hot water at a temperature at which hot water can be supplied without heating in the hot water storage unit, heating by the auxiliary heat source machine is permitted. In the hot water storage and supply system configured as described above, the control means determines the presence or absence of hot water that can be supplied without heating in the hot water storage unit based on the hot water storage temperature and the hot water outlet flow rate, or the hot water storage temperature, the hot water outlet flow rate, and the hot water outlet temperature when hot water is discharged from the hot water storage unit.

[0008] According to the above configuration, when the stored hot water temperature is not a temperature at which hot water can be supplied without heating, it is determined whether there is hot water that can be supplied without heating in the hot water storage unit based on the hot water flow rate in the hot water outlet passage or based on the hot water flow rate and the hot water temperature in the hot water outlet passage. Therefore, even if the stored hot water temperature is not a temperature at which hot water can be supplied without heating, for the hot water that can be supplied without heating in the hot water storage unit, hot water is supplied without heating. When there is no hot water that can be supplied without heating in the hot water storage unit, heating by the auxiliary heat source machine can be permitted and appropriately heated.

[0009] In the hot water storage and supply system according to the invention of claim 2, in the invention of claim 1, when the control means detects that the stored hot water temperature is equal to or higher than a first temperature that is a predetermined temperature higher than the hot water supply set temperature in a state where heating by the auxiliary heat source machine is permitted, it is determined that a transition has occurred to a state where there is hot water that can be supplied without heating in the hot water storage unit. According to the above configuration, when a certain amount of hot water is stored by hot water storage operation in a state where heating by the auxiliary heat source machine is permitted, it is determined that there is hot water that can be supplied without heating in the hot water storage unit. Therefore, heating by the auxiliary heat source machine can be prohibited, and the stored hot water can be supplied without heating. Also, since it takes time from when hot water cannot be supplied without heating until a certain amount of hot water is stored, the permission of heating by the auxiliary heat source machine is not prohibited in a short time. Therefore, short-time heating by the auxiliary heat source machine can be prevented.

[0010] In the hot water storage and supply system according to the invention of claim 3, in the invention of claim 1, as the hot water temperature detection means, there is a tank hot water outlet temperature detection means for detecting the tank hot water outlet temperature of the hot water discharged from the hot water storage tank, and a hot water storage unit hot water outlet temperature detection means for detecting the hot water storage unit hot water outlet temperature of the hot water discharged from the hot water storage unit. When the hot water flow rate is equal to or higher than a first flow rate set in advance, the control means determines whether there is hot water that can be supplied without heating in the hot water storage unit based on the stored hot water temperature. When the hot water flow rate is less than the first flow rate, the control means determines whether there is hot water that can be supplied without heating in the hot water storage unit based on the stored hot water temperature and the tank hot water outlet temperature or the hot water storage unit hot water outlet temperature. According to the above configuration, since the hot water flow rate is large at or above the first flow rate, when the hot water in the hot water storage tank reaches the auxiliary heat source machine immediately, it is determined whether there is hot water that can be supplied for hot water supply without heating in the hot water storage unit based on the stored hot water temperature. Further, when the hot water flow rate is less than the first flow rate, it is determined whether there is hot water that can be supplied for hot water supply without heating in the hot water storage unit based on either the stored hot water temperature or the tank hot water outlet temperature or the hot water storage unit hot water outlet temperature. Therefore, when the hot water flow rate is not large, it is possible to determine whether there is remaining hot water that can be supplied for hot water supply without heating in the hot water outlet passage, and hot water that can be supplied for hot water supply without heating can be supplied for hot water supply without being heated by the auxiliary heat source machine.

[0011] In the hot water storage and supply system of the invention according to claim 4, in the invention according to claim 3, when the hot water flow rate is at or above the first flow rate with the heating by the auxiliary heat source machine prohibited, when it is detected that the stored hot water temperature is lower than a second temperature set lower than a first temperature that is a predetermined temperature higher than the hot water supply set temperature, it is determined that a state has shifted to a state where there is no hot water that can be supplied for hot water supply without heating in the hot water storage unit. According to the above configuration, when the hot water flow rate is at or above the first flow rate and hot water supply is being performed without heating, before the hot water that can be supplied for hot water supply without heating in the hot water storage unit runs out, it is determined that a state has shifted to a state where there is no hot water that can be supplied for hot water supply without heating in the hot water storage unit based on the stored hot water temperature. Since the hot water flow rate is large at or above the first flow rate and the hot water in the hot water storage tank reaches the auxiliary heat source machine immediately, heating by the auxiliary heat source machine can be permitted before the hot water that can be supplied for hot water supply without heating runs out, and the fluctuation of the hot water supply temperature can be reduced by appropriately heating with the auxiliary heat source machine.

[0012] In the hot water storage and supply system of the invention according to claim 5, in the invention according to claim 4, when the hot water flow rate is less than the first flow rate and at or above a preset second flow rate with the heating by the auxiliary heat source machine prohibited, when it is detected that the stored hot water temperature is lower than the second temperature and the tank hot water outlet temperature is lower than the second temperature, it is determined that a state has shifted to a state where there is no hot water that can be supplied for hot water supply without heating in the hot water storage unit. According to the above configuration, when the hot water discharge flow rate is less than the first flow rate and not less than the second flow rate, and it takes a little time until the hot water in the hot water storage tank reaches the auxiliary heat source machine, it is determined that the hot water storage unit has shifted to a state where there is no hot water that can be supplied without heating based on the tank hot water discharge temperature detected by the tank hot water discharge temperature detection means on the upstream side closer to the hot water storage tank among the hot water discharge temperatures. By permitting heating by the auxiliary heat source machine at a timing corresponding to the hot water discharge flow rate, it is possible to appropriately heat with the auxiliary heat source machine and reduce fluctuations in the hot water supply temperature.

[0013] In the hot water storage and supply system of the invention according to claim 6, in the invention according to claim 5, when the hot water discharge flow rate is less than the second flow rate in a state where heating by the auxiliary heat source machine is prohibited, when it is detected that the hot water storage temperature is less than the second temperature and the hot water discharge temperature of the hot water storage unit is less than a third temperature set to be equal to or lower than the second temperature, it is characterized in that it is determined that the hot water storage unit has shifted to a state where there is no hot water that can be supplied without heating. According to the above configuration, when the hot water discharge flow rate is less than the second flow rate and it takes even more time until the hot water in the hot water storage tank reaches the auxiliary heat source machine, it is determined that the hot water storage unit has shifted to a state where there is no hot water that can be supplied without heating based on the hot water discharge temperature of the hot water storage unit detected by the hot water discharge temperature detection means on the downstream side among the hot water discharge temperatures. When the hot water discharge flow rate is small and it takes even more time until the hot water in the hot water storage tank reaches the auxiliary heat source machine, by permitting heating by the auxiliary heat source machine after the hot water that can be supplied without heating in the hot water storage unit runs out, it is possible to appropriately heat with the auxiliary heat source machine and reduce fluctuations in the hot water supply temperature.

Advantages of the Invention

[0014] According to the hot water storage and supply system of the present invention, it is possible to appropriately heat and supply hot water with the auxiliary heat source machine.

Brief Description of the Drawings

[0015]

Figure 1

Figure 2

Figure 3

Embodiments for Carrying Out the Invention

[0016] Hereinafter, embodiments for carrying out the present invention will be described based on examples.

Examples

[0017] First, the configuration of the hot water storage and supply system 1 of the present invention will be described. As shown in FIG. 1, the hot water storage and supply system 1 includes a hot water storage unit 3 having a hot water storage tank 2, a heat pump unit 4 which is a main heat source machine, and an auxiliary heat source machine 5 such as a combustion type. This hot water storage and supply system 1 performs a hot water storage operation of heating the hot water from the hot water storage tank 2 to a predetermined target hot water storage temperature by the heat pump unit 4 and returning the heated hot water to the hot water storage tank 2 for hot water storage.

[0018] The auxiliary heat source machine 5 heats the hot water discharged from the hot water storage unit 3 according to its temperature, or supplies it to the hot water supply faucet 6 without heating, in order to supply hot water at the hot water supply set temperature from the hot water supply faucet 6 as shown by the arrow HW, for example.

[0019] Next, the hot water storage unit 3 will be described. At the lower part of the hot water storage tank 2 of the hot water storage unit 3, a hot water storage forward passage 8 equipped with a hot water storage pump 7 is connected to supply the hot water of the hot water storage tank 2 to the heat pump unit 4. At the upper part of the hot water storage tank 2, a hot water storage return passage 9 for returning the hot water heated by the heat pump unit 4 to the hot water storage tank 2 is connected. A switching valve 10 for switching the flow path of the hot water is arranged in the middle of the hot water storage return passage 9. A return branch passage 9a branched from the hot water storage return passage 9 in this switching valve 10 is connected to an upstream part of the hot water storage pump 7 in the hot water storage forward passage 8.

[0020] Upstream of the switching valve 10 of the hot water return passage 9, a return temperature sensor 9b for detecting the temperature of the hot water heated by the heat pump unit 4 is disposed. For example, immediately after the heat pump unit 4 is started, when the detected temperature of the return temperature sensor 9b is lower than a predetermined hot water storage set temperature, 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 can be circulated without returning it to the hot water storage tank 2 until it can be sufficiently heated.

[0021] A water supply passage 11 for supplying make-up water indicated by the arrow CW is connected to the bottom of the hot water storage tank 2. A hot water discharge passage 12 for discharging the hot water in the hot water storage tank 2 from the hot water storage unit 3 is connected to the top of the hot water storage tank 2. A mixing valve 14 is disposed in the middle of the hot water discharge passage 12, and a water supply branch passage 11a branched from the middle of the water supply passage 11 is connected to the mixing valve 14. Then, the hot water from the hot water storage tank 2 and the make-up water from the water supply branch passage 11a are mixed by the mixing valve 14 and discharged from the hot water storage unit 3.

[0022] A plurality of hot water storage temperature sensors 2a to 2d are disposed in the hot water storage tank 2 at predetermined intervals in the height direction, and the temperature of the hot water stored in the hot water storage tank 2 (hot water storage temperature) and the hot water storage amount of the hot water at that temperature, that is, the hot water storage heat amount, can be detected. And in order to prevent the stored hot water from cooling down, these hot water storage temperature sensors 2a to 2d and a heat insulating material (not shown) covering the hot water storage tank 2 are disposed.

[0023] In the water supply passage 11, a water supply temperature sensor 11b for detecting the temperature of the city water flowing through the water supply passage 11 (water supply temperature) is disposed. In the hot water supply passage 12, a hot water supply flow rate sensor 12a, a tank hot water supply temperature sensor 12b, and a storage unit hot water supply temperature sensor 12c are disposed as hot water supply temperature detection means for detecting the hot water temperature (hot water supply temperature) of the hot water supply passage 12. The hot water supply flow rate sensor 12a is hot water supply flow rate detection means for detecting the hot water supply flow rate from the storage unit 3. The tank hot water supply temperature sensor 12b is tank hot water supply temperature detection means for detecting the temperature of the hot water discharged from the storage tank 2 and supplied to the mixing valve 14 (tank hot water supply temperature). The storage unit hot water supply temperature sensor 12c is storage unit hot water supply temperature detection means for detecting the temperature of the hot water discharged from the storage unit 3 (storage unit hot water supply temperature).

[0024] The downstream end of the hot water supply passage 12 is connected to the water supply port 5a of the auxiliary heat source unit 5, and a hot water passage 16 is connected to the hot water supply port 5b of the auxiliary heat source unit 5. To the hot water passage 16, for example, a kitchen hot water faucet 6, a faucet or a shower in a bathroom (not shown) are connected as the hot water supply destination.

[0025] The storage unit 3 has a storage unit control unit 18 (control means) for controlling the temperature adjustment of the hot water discharged from the storage unit 3. The storage unit control unit 18 drives the heat pump unit 4 and the storage pump 7 to control a storage operation of storing the hot water heated to the target storage temperature by the heat pump unit 4 from the upper part of the storage tank 2. The stored heat quantity of the storage tank 2 is calculated by the storage unit control unit 18 based on the detected temperatures of, for example, the storage temperature sensors 2a to 2d.

[0026] When the hot water supply flow rate sensor 12a detects a flow rate equal to or higher than a predetermined flow rate, the storage unit control unit 18 adjusts the mixing ratio of the mixing valve 14 to perform temperature adjustment and supply hot water. The mixing ratio is adjusted based on the storage temperature, the water supply temperature, and the tank hot water supply temperature so that the storage unit hot water supply temperature becomes a predetermined hot water supply temperature.

[0027] At this time, a first temperature and a second temperature are set with respect to the hot water supply set temperature. The first temperature is a temperature that is higher than the hot water supply set temperature by a predetermined temperature (for example, 4°C). The second temperature is the same temperature as the hot water supply set temperature or a temperature that is higher than the hot water supply set temperature (for example, 1°C higher) and lower than the first temperature. And when there is hot water at or above the second temperature in the hot water storage tank 2, the mixing ratio of the mixing valve 14 is adjusted so that the hot water outlet temperature of the hot water storage unit becomes the hot water supply set temperature, and hot water is discharged. Also, when there is no hot water at or above the second temperature in the hot water storage tank 2, the mixing ratio of the mixing valve 14 is adjusted so that the hot water outlet temperature of the hot water storage unit is lower than the temperature to be heated, and hot water is discharged. The temperature to be heated is set to a temperature that is lower than the hot water supply set temperature by a predetermined temperature (for example, 10°C).

[0028] An operation remote controller 19 for the user to set, for example, the hot water supply set temperature and the like is connected to the hot water storage unit control unit 18 and the auxiliary heat source machine 5. A plurality of operation remote controllers 19 may be connected, and the operation remote controller 19 corresponding to the hot water storage unit 3 may be connected to the hot water storage unit control unit 18, and the operation remote controller corresponding to the auxiliary heat source machine 5 may be connected to the auxiliary heat source machine 5.

[0029] Next, the hot water supply operation of the hot water storage and supply system 1 will be described based on the hot water supply operation flowchart of FIG. 2. Si (i = 1, 2, ···) in the figure represents steps. When the hot water outlet flow rate sensor 12a detects a flow rate equal to or higher than a predetermined flow rate, the hot water supply operation is started. First, in S1, the water supply temperature, the hot water storage temperature, the tank hot water outlet temperature, the hot water storage unit hot water outlet temperature, and the hot water outlet flow rate are acquired, and the process proceeds to S2. Then, in S2, an auxiliary heat source machine heating determination for determining whether heating by the auxiliary heat source machine 5 is possible is performed, and the process proceeds to S3. This is a step for performing the determination because the heating by the auxiliary heat source machine 5 may be changed from prohibited to permitted or from permitted to prohibited during the hot water supply operation.

[0030] Next, in S3, it is determined whether the heating by the auxiliary heat source unit 5 is in a prohibited state. If the determination in S3 is Yes, the process proceeds to S4. In S4, the mixing ratio of the mixing valve 14 is set so that the hot water outlet temperature from the hot water storage unit 3 (hot water storage unit hot water outlet temperature) becomes the hot water supply set temperature, and the process proceeds to S5. Then, in S5, hot water is supplied without heating via the auxiliary heat source unit 5, and the process proceeds to S8.

[0031] On the other hand, if the determination in S3 is No, the process proceeds to S6. In S6, the mixing ratio of the mixing valve 14 is set so that the hot water outlet temperature from the hot water storage unit 3 (hot water storage unit hot water outlet temperature) is equal to or lower than the temperature requiring heating, and the process proceeds to S7. Then, in S7, hot water adjusted to the hot water supply set temperature by heating with the auxiliary heat source unit 5 is supplied, and the process proceeds to S8.

[0032] Next, in S8, it is determined whether the hot water outlet flow rate has become zero, that is, whether the hot water supply use has ended. If the determination in S8 is No, the hot water supply continues, and the process returns to S1. If the determination in S8 is Yes, the hot water supply operation ends.

[0033] Next, the determination of the auxiliary heat source unit heating in S2 of FIG. 2 will be described with reference to FIG. 3. First, in S11, it is determined whether the heating by the auxiliary heat source unit 5 is in a prohibited state. If the determination in S11 is Yes, the process proceeds to S12. In S12, it is determined whether the hot water outlet flow rate is equal to or greater than the first flow rate. The first flow rate is appropriately set according to the specifications of the hot water storage and supply system 1 and is set to, for example, 15 L / min.

[0034] If the determination in S12 is Yes, the process proceeds to S13. In S13, it is determined whether the hot water storage temperature is less than the second temperature. The hot water storage temperature used in the determination in this step and other steps is the detected temperature of the hot water storage temperature sensor 2d arranged at the uppermost position among the plurality of hot water storage temperature sensors 2a to 2d. If the determination in S13 is Yes, the process proceeds to S14. In S14, it is assumed that there is no hot water that can be supplied to the hot water storage unit 3 without heating, and the process proceeds to S15. Then, in S15, the heating by the auxiliary heat source unit 5 is permitted, and the process returns.

[0035] On the other hand, if the determination in S12 is No, the process proceeds to S16, and in S16, it is determined whether the hot water flow rate is equal to or greater than the second flow rate. The second flow rate is appropriately set according to the specifications of the hot water storage and supply system 1, and is set to, for example, 8 L / min.

[0036] If the determination in S16 is Yes, the process proceeds to S17, and in S17, it is determined whether the stored hot water temperature is less than the second temperature. If the determination in S17 is Yes, the process proceeds to S18, and in S18, it is determined whether the tank hot water outlet temperature is less than the second temperature. This is a step of determining whether the hot water in the hot water storage tank 2 at a temperature less than the second temperature has reached the mixing valve 14. If the determination in S18 is Yes, the process proceeds to S14, and thereafter, heating by the auxiliary heat source machine 5 is permitted and the process returns as described above.

[0037] If the determination in S16 is No, the process proceeds to S19, and in S19, it is determined whether the stored hot water temperature is less than the second temperature. If the determination in S19 is Yes, the process proceeds to S20, and in S20, it is determined whether the hot water outlet temperature of the hot water storage unit is less than the third temperature. This is a step of determining whether the hot water in the hot water storage tank 2 at a temperature less than the second temperature has reached the hot water outlet temperature sensor 12c of the hot water storage unit, and the third temperature is set to be equal to or less than the second temperature in consideration of the mixing of the make-up water in the mixing valve 14. If the determination in S20 is Yes, the process proceeds to S14, and thereafter, heating by the auxiliary heat source machine 5 is permitted and the process returns as described above.

[0038] On the other hand, if the determination in S11 is No, the process proceeds to S21, and in S21, it is determined whether the stored hot water temperature is equal to or greater than the first temperature. If the determination in S21 is Yes, the process proceeds to S22. Assuming that there is hot water in the hot water storage unit 3 that can supply hot water without heating in S22, the process proceeds to S23. Then, in S23, heating by the auxiliary heat source machine 5 is prohibited and the process returns. If the determination in S21 is No, the process proceeds to S14, and thereafter, heating by the auxiliary heat source machine 5 is permitted and the process returns as described above.

[0039] If the determination in S13 is No or if the determinations in S17 to S20 are No, the process proceeds to S22. Since the subsequent steps are the same as described above, the description is omitted, but heating by the auxiliary heat source machine 5 is prohibited and the process returns.

[0040] As described above, during the hot water supply operation, that is, when hot water is discharged from the hot water storage unit 3, the hot water storage supply system 1 determines the presence or absence of hot water that can be supplied without heating in the hot water storage unit 3 based on the hot water storage temperature, or based on the hot water storage temperature, the hot water discharge temperature, and the hot water discharge flow rate. Then, by permitting heating by the auxiliary heat source unit 5 based on this determination result, short-time heating by the auxiliary heat source unit 5 can be prevented, and appropriate heating and hot water supply can be achieved.

[0041] The operation and effects of the above-described hot water storage supply system 1 will be described. The hot water storage supply system 1 is configured to prohibit heating by the auxiliary heat source unit 5 when the hot water storage unit control unit 18 determines that there is hot water at a temperature at which hot water can be supplied without heating in the hot water storage unit 3, and to permit heating by the auxiliary heat source unit 5 when it is determined that there is no hot water at a temperature at which hot water can be supplied without heating in the hot water storage unit 3. The determination of the presence or absence of hot water that can be supplied without heating in the hot water storage unit 3 is made based on the hot water storage temperature and the hot water discharge flow rate, or based on the hot water storage temperature, the hot water discharge flow rate, and the hot water discharge temperature when hot water is discharged from the hot water storage unit 3.

[0042] Thereby, when the hot water storage temperature is not a temperature at which hot water can be supplied without heating, the presence or absence of hot water that can be supplied without heating in the hot water storage unit 3 is determined based on the hot water discharge flow rate in the hot water discharge passage 12, or based on the hot water discharge flow rate and the hot water discharge temperature. Therefore, when it is determined that there is hot water that can be supplied without heating in the hot water storage unit 3, heating by the auxiliary heat source unit 5 can be prohibited and hot water can be supplied without heating. Also, when it is determined that there is no hot water that can be supplied without heating in the hot water storage unit 3, heating by the auxiliary heat source unit 5 can be permitted and appropriate heating can be achieved. On the other hand, when the hot water storage temperature is a temperature at which hot water can be supplied without heating, heating by the auxiliary heat source unit 5 is prohibited, so short-time heating by the auxiliary heat source unit 5 at the start of hot water supply, when hot water with a reduced temperature in the hot water discharge passage 12 is supplied to the auxiliary heat source unit 5, is prohibited.

[0043] When the hot water storage unit control unit 18 detects that the stored hot water temperature is equal to or higher than a first temperature that is a predetermined temperature higher than the hot water supply set temperature in a state where heating by the auxiliary heat source unit 5 is permitted, it determines that the state has shifted to a state where there is hot water that can be supplied for hot water supply without heating in the hot water storage unit 3. When a certain amount of hot water is stored by hot water storage operation in a state where heating by the auxiliary heat source unit 5 is permitted, by prohibiting the heating by the auxiliary heat source unit 5, it is possible to prevent the permission of heating by the auxiliary heat source unit 5 from being prohibited in a short time, and it is possible to prevent short-time heating with low operation efficiency by the auxiliary heat source unit 5.

[0044] When the hot water discharge flow rate is large and equal to or higher than a first flow rate set in advance, since the hot water in the hot water storage tank 2 reaches the auxiliary heat source unit 5 immediately, the hot water storage unit control unit 18 determines the presence or absence of hot water that can be supplied for hot water supply without heating in the hot water storage unit 3 based on the stored hot water temperature. When the hot water discharge flow rate is less than the first flow rate, the hot water storage unit control unit 18 determines the presence or absence of hot water that can be supplied for hot water supply without heating in the hot water storage unit 3 based on either the stored hot water temperature or the tank hot water discharge temperature or the hot water storage unit hot water discharge temperature. Therefore, when the hot water discharge flow rate is not large, it is possible to determine whether there is hot water that can be supplied for hot water supply without heating remaining in the hot water discharge passage 12, and it is possible to supply hot water without heating the hot water that can be supplied for hot water supply by the auxiliary heat source unit 5.

[0045] When the hot water storage unit control unit 18 is in a state where heating by the auxiliary heat source unit 5 is prohibited, when the hot water discharge flow rate is equal to or higher than the first flow rate and it detects that the stored hot water temperature is less than a second temperature, it determines that the state has shifted to a state where there is no hot water that can be supplied for hot water supply without heating in the hot water storage unit 3. When the hot water in the hot water storage tank 2 reaches the auxiliary heat source unit 5 immediately because the hot water discharge flow rate is large and equal to or higher than the first flow rate, it is possible to permit heating by the auxiliary heat source unit 5 before the hot water that can be supplied for hot water supply without heating in the hot water storage unit 3 runs out, and it is possible to appropriately heat by the auxiliary heat source unit 5 to reduce fluctuations in the hot water supply temperature.

[0046] When the hot water storage unit control unit 18 prohibits heating by the auxiliary heat source machine 5 and the hot water supply flow rate is less than the first flow rate and equal to or greater than a preset second flow rate, and when it detects that the hot water storage temperature is less than the second temperature and the hot water storage tank hot water supply temperature is less than the second temperature, it determines that the hot water storage unit 3 has shifted to a state where there is no hot water that can be supplied without heating. When it takes a little time for the hot water in the hot water storage tank 2 to reach the auxiliary heat source machine 5, heating by the auxiliary heat source machine 5 can be permitted based on the tank hot water supply temperature detected by the tank hot water supply temperature sensor 12b on the upstream side closer to the hot water storage tank 2 among the hot water supply temperatures. By permitting heating by the auxiliary heat source machine 5 at a timing corresponding to the hot water supply flow rate, it is possible to appropriately heat with the auxiliary heat source machine 5 and reduce fluctuations in the hot water supply temperature.

[0047] When the hot water storage unit control unit 18 prohibits heating by the auxiliary heat source machine 5 and the hot water supply flow rate is less than the second flow rate, and when it detects that the hot water storage temperature is less than the second temperature and the hot water storage unit hot water supply temperature is less than a third temperature set to be equal to or lower than the second temperature, it determines that the hot water storage unit 3 has shifted to a state where there is no hot water that can be supplied without heating. When it takes even more time for the hot water in the hot water storage tank 2 to reach the auxiliary heat source machine 5, by permitting heating by the auxiliary heat source machine 5 after the hot water that can be supplied without heating in the hot water storage unit 3 has run out, it is possible to appropriately heat with the auxiliary heat source machine 5 and reduce fluctuations in the hot water supply temperature.

[0048] The hot water storage unit control unit 18 may be configured to determine that the hot water storage unit 3 has shifted to a state where there is no hot water that can be supplied without heating when, in a state where heating by the auxiliary heat source machine 5 is prohibited, even when the hot water supply flow rate is zero, due to heat dissipation, it detects that the hot water storage temperature is less than the second temperature and the hot water storage tank hot water supply temperature is less than the second temperature, and the hot water storage unit hot water supply temperature is less than a third temperature set to be equal to or lower than the second temperature. In addition, those skilled in the art can implement the present invention in various modified forms without departing from the spirit of the present invention, and the present invention includes such modified forms.

Explanation of Reference Numerals

[0049] 1: Hot water storage and supply system 2: Hot water storage tank 2a~2d: Hot water storage temperature sensor (hot water storage temperature detection means) 3: Hot water storage unit 4: Heat pump unit (main heat source machine) 5: Auxiliary heat source machine 6: Hot water faucet 7: Hot water storage pump 8: Hot water supply passage 9: Hot water return passage 9a: Return branch passage 9b: Return temperature sensor 11: Water supply passage 11a: Water supply branch passage 11b: Water supply temperature sensor 12: Hot water discharge passage 12a: Hot water discharge flow sensor (hot water discharge flow detection means) 12b: Tank hot water discharge temperature sensor (tank hot water discharge temperature detection means) 12c: Hot water storage unit hot water discharge temperature sensor (hot water storage unit hot water discharge temperature detection means) 14: Mixing valve 16: Hot and cold water passage 18: Hot water storage unit control unit (control means) 19: Operation remote control

Claims

1. A hot water storage and supply system having a hot water storage unit with a hot water storage tank for storing hot water, a main heat source unit for heating the hot water in the hot water storage tank to store hot water in the hot water storage tank, an auxiliary heat source unit for heating or not heating the hot water in the hot water storage tank to supply hot water, a hot water outlet passage connecting the hot water storage tank and the auxiliary heat source unit, hot water storage temperature detecting means for detecting the hot water storage temperature of the hot water in the hot water storage tank, hot water outlet temperature detecting means for detecting the hot water outlet temperature of the hot water in the hot water outlet passage, hot water outlet flow rate detecting means for detecting the hot water outlet flow rate of the hot water in the hot water outlet passage, and control means for controlling hot water storage and supply. When the control means determines that there is hot water at a temperature at which hot water can be supplied without heating in the hot water storage unit, heating by the auxiliary heat source unit is prohibited. When the control means determines that there is no hot water at a temperature at which hot water can be supplied without heating in the hot water storage unit, heating by the auxiliary heat source unit is permitted. In the hot water storage and supply system, The control means determines the presence or absence of hot water that can be supplied without heating in the hot water storage unit based on the hot water storage temperature and the hot water outlet flow rate, or based on the hot water storage temperature, the hot water outlet flow rate, and the hot water outlet temperature when hot water is discharged from the hot water storage unit. A hot water storage and supply system characterized by this.

2. When the control means detects that the hot water storage temperature is equal to or higher than a first temperature that is a predetermined temperature higher than the hot water supply set temperature in a state where heating by the auxiliary heat source unit is permitted, it is determined that a state has shifted to a state where there is hot water that can be supplied without heating in the hot water storage unit. The hot water storage and supply system according to Claim 1, characterized by this.

3. As the hot water outlet temperature detecting means, there is tank hot water outlet temperature detecting means for detecting the tank hot water outlet temperature of the hot water discharged from the hot water storage tank, and hot water storage unit hot water outlet temperature detecting means for detecting the hot water storage unit hot water outlet temperature of the hot water discharged from the hot water storage unit. When the hot water outlet flow rate is equal to or higher than a first flow rate set in advance, the control means determines the presence or absence of hot water that can be supplied without heating in the hot water storage unit based on the hot water storage temperature. When the hot water outlet flow rate is less than the first flow rate, the control means determines the presence or absence of hot water that can be supplied without heating in the hot water storage unit based on the hot water storage temperature and the tank hot water outlet temperature or the hot water storage unit hot water outlet temperature. The hot water storage and supply system according to Claim 1, characterized by this.

4. The storage hot water supply system according to claim 3, wherein when the control means prohibits heating by the auxiliary heat source machine and the hot water supply flow rate is equal to or higher than the first flow rate, and it is detected that the stored hot water temperature is lower than a second temperature set lower than a first temperature that is a predetermined temperature higher than the hot water supply set temperature, the control means determines that the system has shifted to a state where there is no hot water that can be supplied without heating in the hot water storage unit.

5. The storage hot water supply system according to claim 4, wherein when the control means prohibits heating by the auxiliary heat source machine and the hot water supply flow rate is less than the first flow rate and equal to or higher than a preset second flow rate, and it is detected that the stored hot water temperature is lower than the second temperature and the hot water outlet temperature of the hot water storage tank is lower than the second temperature, the control means determines that the system has shifted to a state where there is no hot water that can be supplied without heating in the hot water storage unit.

6. The storage hot water supply system according to claim 5, wherein when the control means prohibits heating by the auxiliary heat source machine and the hot water supply flow rate is less than the second flow rate, and it is detected that the stored hot water temperature is lower than the second temperature and the hot water outlet temperature of the hot water storage unit is lower than a third temperature set to be equal to or lower than the second temperature, the control means determines that the system has shifted to a state where there is no hot water that can be supplied without heating in the hot water storage unit.

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