JP2015059681A - Storage water heater - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable prevention of a cold water sandwiching phenomenon when tank hot water delivery is switched to auxiliary heating hot water delivery during a heat use terminal operation, etc. in a storage water heater.SOLUTION: A storage water heater 1 includes an auxiliary heat source machine 3, a hot water supply passage 21, a tank hot water delivery passage 22, an auxiliary heating passage 23 and an auxiliary heat source machine hot water delivery passage 24. When a temperature of hot water in a hot water storage tank 2 reaches a hot water supply set temperature or lower, the tank hot water delivery passage 22 is switched to the auxiliary heating passage 23 by using a three-way valve 26, and before tank hot water delivery is switched to auxiliary heating hot water delivery, the storage water heater performs a circulating heating operation for circulating hot water in a heat use circulation circuit 9 by operating a pressure pump 27 and the auxiliary heat source machine 3 to heat hot water that is present within the auxiliary heating passage 23 and the auxiliary heat source machine hot water delivery passage 24. When the circulating heating operation is executed, if a heat use terminal operation is being executed in a heat use heat exchanger 4, a control unit 35 stops the heat use terminal operation during the circulating heating operation.

Description

  The present invention relates to a hot water storage hot water supply apparatus, and more particularly to an apparatus for reheating hot water by using an auxiliary heat source device when a hot water temperature of a hot water storage tank is lowered.

  2. Description of the Related Art Conventionally, hot water storage and hot water supply devices that can generate hot water and store hot water and supply it to a desired hot water supply destination have been put to practical use. This type of hot water storage and hot water supply system has a hot water storage tank for storing hot water, various valve members and various pipes, and an auxiliary heat source for reheating when the temperature of the hot water stored in the hot water storage tank is low. Machine, an exterior case containing these devices, an external heat source machine for generating hot water, and the like.

  When reheating hot water using the above auxiliary heat source machine, it is generally performed as follows. That is, when the amount of hot water that can be supplied in the hot water storage tank decreases during the hot water supply operation and the hot water temperature in the upper part of the hot water storage tank falls below the preset hot water supply temperature, the hot water is directly discharged from the hot water storage tank through the hot water supply passage. From the tank hot water, the hot water is reheated through the auxiliary heat source machine and then switched to the auxiliary heated hot water that is discharged through the hot water supply passage.

  By the way, immediately after switching from the tank hot water to the auxiliary heating hot water, the temperature of the hot water flowing through the hot water supply passage is temporarily lowered by the low temperature hot water in the pipe near the auxiliary heat source machine being discharged. Occur.

  Conventionally, in order to prevent the cold water sandwich phenomenon, a heat circulation circuit for heating the bath water of the bath chase circuit and the heating water of the hot water heating circuit, from the auxiliary heat source machine and the hot water storage tank to the auxiliary heat source machine Before using the heat utilization circulation circuit including the passage to be connected and the passage to be connected to the hot water supply passage from the auxiliary heat source machine, before switching from the tank hot water to the auxiliary heating hot water, the hot water is circulated in the heat utilization circulation circuit, and the auxiliary heat source machine A circulation heating operation (circulation heating operation) is performed in which the hot water in the heat utilization circulation circuit is preheated by burning the water.

  Moreover, in the hot water supply system of Patent Document 1, the auxiliary heat source machine, the passage connecting from the hot water storage tank to the auxiliary heat source machine, the passage connecting from the auxiliary heat source machine to the hot water supply passage, and the auxiliary heat source machine from above the hot water storage tank are bypassed. A loop circulation circuit is formed from the passage directly connected to the hot water supply passage, and after the hot water supply operation using the auxiliary heat source machine is completed, the auxiliary heat source machine is continuously driven for a certain period of time to supply hot hot water to the loop circulation circuit. There is also disclosed a technique for preventing the occurrence of a cold water sandwich phenomenon by performing a post-circulation operation that circulates and retains hot hot water in a loop-shaped circulation circuit.

JP 2012-72952 A

  However, when the outside air temperature decreases in cold regions or winter, the freezing prevention operation of the bath chase circuit or hot water heating circuit is executed as the heat utilization terminal operation, but if the circulating heating operation is executed during this freezing prevention operation Since the hot water heated by the auxiliary heat source device is cooled by the heat utilization heat exchanger of the heat utilization circulation circuit, there is a possibility that the elimination of the cold water sandwich phenomenon may be insufficient.

  Moreover, if the technique which circulates the hot water heated with the auxiliary heat source machine to a loop-shaped circulation circuit like the post-circulation operation of the hot water supply system of patent document 1, it will produce | generate the hot hot water which does not contribute to hot water supply. The operating efficiency of the hot water storage and hot water supply device is reduced.

  An object of the present invention is to make it possible to prevent a cold water sandwich phenomenon from occurring when a hot water storage terminal is switched from a tank hot water to an auxiliary heating hot water during a heat utilization terminal operation, and to prevent a decrease in operating efficiency. And so on.

  The hot water storage and hot water supply apparatus according to claim 1 includes a tank hot water passage connected from the upper part of the hot water storage tank to the hot water supply passage, an auxiliary heating passage branched from the tank hot water passage and connected to an auxiliary heat source device, and the auxiliary heat source device From the auxiliary heat source machine hot water passage connected to the hot water supply passage, the switching means capable of switching between the tank hot water passage and the auxiliary heating passage, the circulation means installed in the auxiliary heating passage, and the auxiliary heat source machine hot water passage A heat utilization circulation passage that is branched and connected to the auxiliary heating passage; and a heat utilization heat exchanger that is installed in the heat utilization circulation passage, and the hot water temperature of the hot water storage tank is equal to or lower than a hot water supply set temperature. In the hot water storage and hot water supply apparatus for switching from the tank hot water passage to the auxiliary heating passage by the switching means, the tank hot water discharged from the hot water storage tank through the tank hot water passage. Before switching to the auxiliary heating hot water to be discharged through the auxiliary heat source unit, the circulating means and the auxiliary heat source unit are driven to circulate hot water in the heat utilization circulation passage and at least in the auxiliary heating passage and the And a control means capable of performing a circulating heating operation for heating hot water present in the auxiliary heat source machine outlet hot water passage, wherein the control means is a heat utilization terminal in the heat utilization heat exchanger when the circulation heating operation is performed. When the operation is being performed, the heat utilization terminal operation is stopped during the circulation heating operation.

  The hot water storage and hot water supply apparatus according to claim 2 is characterized in that, in the invention of claim 1, the heat utilization terminal operation is a freeze prevention operation.

  According to the first aspect of the present invention, when the heat utilization terminal operation is performed in the heat utilization heat exchanger when the circulation heating operation is performed, the control means performs the heat utilization terminal operation during the circulation heating operation. Stop temporarily.

  Therefore, hot water heated by the auxiliary heat source unit in the circulating heating operation can be prevented from being dissipated by the heat-utilizing heat exchanger, thus reliably preventing the cold water sandwich phenomenon and switching from the tank hot water to the auxiliary heating hot water. Immediately after the hot water heated by the auxiliary heat source device can be effectively supplied to the hot water supply passage, it is possible to prevent deterioration of the hot water supply characteristics.

  According to the invention of claim 2, since the heat utilization terminal operation is a freeze prevention operation in which the heat radiation amount in the heat utilization heat exchanger is particularly large, the heat utilization terminal operation is performed simultaneously with the heat utilization terminal operation and the circulation heating operation. By stopping the operation, the cooling of the hot water heated by the auxiliary heat source device can be surely prevented, and the occurrence of the cold water sandwich phenomenon can be more reliably prevented.

It is a schematic block diagram of the hot water storage hot-water supply apparatus which concerns on the Example of this invention. It is a flowchart of the first half part of hot water supply operation control. It is a flowchart of the second half part of hot water supply operation control. It is a schematic block diagram of the hot water storage hot-water supply apparatus at the time of a hot water supply operation (tank hot water) and a freeze prevention operation. It is a schematic block diagram of the hot water storage hot-water supply apparatus at the time of a hot water supply operation (tank hot water) and a circulating heating operation. It is a schematic block diagram of the hot water storage hot-water supply apparatus at the time of hot water supply operation (auxiliary heating hot water) and freezing prevention operation.

  Hereinafter, modes for carrying out the present invention will be described based on examples.

First, the whole structure of the hot water storage hot-water supply apparatus 1 of this invention is demonstrated.
As shown in FIG. 1, the hot water storage and hot water supply device 1 has functions such as hot water storage, hot water supply, and bathing, and the tank unit 1A including the hot water storage tank 2 and hot water in the hot water storage tank 2 are heated. The external heat source unit 10, the hot water circulation circuit 6 that connects the tank unit 1 </ b> A and the external heat source unit 10 are provided.

  The tank unit 1A includes a hot water storage tank 2, an auxiliary heat source device 3, a heat-utilizing heat exchanger 4, a water supply system passage 5, a hot water circulation circuit 6, a hot water supply system passage 7, and a bath memory circuit 8 that replenishes bath water in the bath. A heat-utilizing circuit 9 for heating the bath water of the bath chase circuit 8 and the like are provided, and most of them are integrally stored in the outer case 11. As the external heat source unit 10, a heat pump type heat source unit, an exhaust heat recovery heat exchanger of a fuel cell power generation unit, or the like is used.

Next, the hot water storage tank 2 will be described.
As shown in FIG. 1, the hot water storage tank 2 is composed of a sealed tank capable of storing high-temperature hot water (for example, 65 to 90 ° C.) heated by the external heat source unit 10 to prevent heat dissipation of the stored hot water. The tank is covered with insulation.

  A plurality of hot water temperature detection sensors 2a to 2d are provided in order at equal intervals from the lower side to the upper side on the outer periphery of the hot water storage tank 2, and a plurality of hot water temperature detection sensors 2a to 2d are provided in the plurality of hot water temperature detection sensors 2a to 2d. The hot water temperature of the reservoir is detected.

  The auxiliary heat source unit 3 is composed of a known gas water heater that incorporates a burner, a heat exchanger, and the like. The auxiliary heat source unit 3 is heated only when a command is transmitted from the control unit 35 in response to a special case such as when the hot water temperature in the hot water storage tank 2 is lowered, and heats the hot water. On the outlet side of the auxiliary heat source unit 3, a hot water temperature detection sensor 3a capable of detecting the hot water temperature derived from the auxiliary heat source unit 3 is provided.

  The heat utilization heat exchanger 4 heats the bath water flowing through the bath remedy circuit 8, and becomes a part of the heat exchange passage 4 a and the bath remedy circuit 8 that are part of the heat utilization circulation circuit 9. It has a heat exchange passage 4b. In this heat utilization heat exchanger 4, heat is exchanged between hot water flowing through the heat utilization circulation circuit 9 and bathtub water flowing through the bath memory circuit 8, and the bathtub water is heated.

Next, the water supply system passage 5 will be described.
As shown in FIG. 1, the water supply system passage 5 supplies low temperature clean water from a water supply source to the hot water storage tank 2, and has an upstream water supply passage portion 5a, an intermediate water supply passage portion 5b, and a downstream water supply passage portion 5c. doing. An upstream end of the upstream water supply passage portion 5 a is connected to a water source, and a downstream end of the downstream water supply passage portion 5 c is connected to a lower portion of the hot water storage tank 2. A bypass passage portion 12 connected to the hot water supply passage 7 is branched from between the upstream water supply passage portion 5a and the intermediate water supply passage portion 5b.

  An on-off valve 5e is installed in the upstream water supply passage 5a, and the on-off valve 5e is normally opened so that low-temperature clean water is supplied into the hot water storage tank 2. A check valve 5d is installed in the intermediate water supply passage 5b, and a check valve 12a is installed in the bypass passage 12.

  A bypass passage 14 connected to the heat utilization circuit 9 is branched from between the intermediate water supply passage 5b and the downstream water supply passage 5c, and a heat storage switching valve 15 is installed at this branch. By this bypass passage 14, low temperature clean water can be supplied to the heat utilization circuit 9, and conversely, hot water can be returned from the heat utilization circuit 9 to the hot water storage tank 2.

Next, the hot water circulation circuit 6 will be described.
As shown in FIG. 1, the hot water circulation circuit 6 is a closed circuit that circulates and heats hot water between the hot water storage tank 2 and the external heat source unit 10, and includes a low temperature side circulation passage portion 6a and a high temperature side circulation passage portion 6b. Etc. The upstream end of the low temperature side circulation passage portion 6 a is connected to the lower portion of the hot water storage tank 2, and the downstream end of the high temperature side circulation passage portion 6 b is connected to the upper portion of the hot water storage tank 2.

  A branch passage portion 16 connected to the high temperature side circulation passage portion 6b is branched from the low temperature side circulation passage portion 6a, and a circulation circuit including the hot water storage tank 2 and a circulation circuit bypassing the hot water storage tank 2 are selected in this branch portion. A uniquely selectable three-way valve 17 is provided. A circulation pump 18 is installed on the downstream side of the three-way valve 17 in the low temperature side circulation passage portion 6a. A heat exchanging portion 10a of the external heat source device 10 is provided between the downstream end of the low temperature side circulation passage portion 6a and the upstream end of the high temperature side circulation passage portion 6b.

Next, the hot water supply system passage 7 will be described.
As shown in FIG. 1, the hot water supply passage 7 supplies hot water stored in the hot water storage tank 2 to a desired hot water supply destination such as a bath, and the hot water supply passage 21 connected to the hot water tap, the hot water storage tank 2. A tank hot water passage 22 connected to the hot water supply passage 21 from above, an auxiliary heating passage 23 branched from the tank hot water passage 22 and connected to the combustion type auxiliary heat source device 3, and an auxiliary heat source device 3 connected to the hot water supply passage 21. The auxiliary heat source machine outlet hot water passage 24 and the like are provided.

  The hot water supply passage 21 has an upstream hot water supply passage portion 21a through which high-temperature hot water flows and a downstream hot water supply passage portion 21b through which mixed hot water flows. The upstream end of the upstream hot water supply passage portion 21a is connected to the downstream end of the tank hot water supply passage 22 and The downstream end of the hot water passage 21b is connected to the hot water tap.

  A mixing valve 25 is installed between the upstream hot water supply passage portion 21a and the downstream hot water supply passage portion 21b. A bypass passage portion 12 branched from the water supply passage 5 is connected to the mixing valve 25. The mixing valve 25 controls the mixing ratio of water and hot hot water so that the hot water temperature becomes the command temperature.

  The tank outlet 22 has an upper outlet hot water passage 22a and a lower outlet hot water passage 22b. The upstream end of the upper outlet hot water passage 22a is connected to the upper part of the hot water storage tank 2 and is downstream of the lower outlet hot water passage 22b. The end is connected to the upstream end of the upstream hot water supply passage 21a. An auxiliary heating passage 23 is branched from between the upper effluent passage portion 22a and the lower effluent passage portion 22b.

  The auxiliary heating passage 23 has an upstream heating passage portion 23a and a downstream heating passage portion 23b, the upstream end of the upstream heating passage portion 23a is connected to the tank outlet passage 22, and the downstream end of the downstream heating passage portion 23b is an auxiliary heat source machine. 3 is connected to the inlet.

  Between the upstream heating passage portion 23a and the downstream heating passage portion 23b, a three-way valve 26 (corresponding to switching means) capable of switching between the tank hot water passage 22 and the auxiliary heating passage 23 is installed. The three-way valve 26 is also connected to the hot water return side passage 9b of the heat utilization circuit 9. This three-way valve 26 can switch connection / disconnection between the upstream heating passage portion 23a and the downstream heating passage portion 23b and connection / disconnection between the downstream heating passage portion 23b and the hot water return side passage portion 9b. is there. A pressure feed pump 27 (corresponding to a circulation means) is installed in the downstream heating passage portion 23b.

  The auxiliary heat source machine outlet passage 24 has an upstream auxiliary outlet passage portion 24a and a downstream auxiliary outlet passage portion 24b, and the upstream end of the upstream auxiliary outlet passage portion 24a is connected to the outlet of the auxiliary heat source unit 3, and the downstream auxiliary outlet passage The downstream end of the portion 24b is connected to the upstream end of the upstream hot water supply passage portion 21a. A hot water / outward side passage portion 9a of the heat utilization circulation circuit 9 is branched from between the upstream auxiliary hot water passage portion 24a and the downstream auxiliary hot water passage portion 24b. A tank water proportional valve 28 is provided in the downstream auxiliary hot water passage portion 24b.

Next, the bath memory circuit 8 will be described.
As shown in FIG. 1, the bath chase circuit 8 is a circuit that circulates bath water in order to chase the bath water of the bath, and has a bath return side passage portion 8a and a bath outlet side passage portion 8b. Yes. A bath circulation pump 8c is installed between the bath return side passage 8a and the bath going side passage 8b, and the heat exchange passage 4b of the heat-use heat exchanger 4 is installed in the bath going side passage 8b.

Next, the heat utilization circulation circuit 9 will be described.
As shown in FIG. 1, the heat utilization circulation circuit 9 is a closed circuit that circulates hot water and exchanges heat with the bath remedy circuit 8, and includes a hot water forward side passage portion 9 a and a hot water return side passage portion 9 b. The auxiliary heating passage 23 includes a downstream heating passage portion 23b and an auxiliary heat source machine outlet passage 24 upstream of the auxiliary heating passage portion 24a. The heat exchange passage portion 4a of the heat-use heat exchanger 4 is connected between the hot water going-side passage portion 9a and the hot water return side passage portion 9b. The hot water outlet side passage portion 9 a and the hot water return side passage portion 9 b correspond to a heat utilization circulation passage branched from the auxiliary heat source machine outlet hot water passage 24 and connected to the auxiliary heating passage 23.

  When hot water is circulated in the heat utilization circulation circuit 9 to exchange heat with bathtub water, hot water flows into the auxiliary heat source unit 3 from the downstream heating passage portion 23b via the pressure feed pump 27 and is heated by the auxiliary heat source unit 3. After that, the hot hot water flows through the upstream auxiliary hot water outlet passage portion 24a and the hot water forward passage portion 9a and is sent to the heat exchange passage portion 4a, and heat is exchanged with the bath water in the heat exchange passage portion 4a. The hot water is returned to the downstream heating passage portion 23b through the hot water return side passage portion 9b.

Next, the control unit 35 will be described.
As shown in FIG. 1, the hot water storage and hot water supply apparatus 1 is controlled by a control unit 35 (corresponding to control means). Detection signals of various sensors are transmitted to the control unit 35, and the control unit 35 controls the operation of the hot water storage hot water supply device 1, the operation / stop of various pumps, the switching of the open / close states of various valves, the opening degree adjustment, and the like. Then, various operations (hot water supply operation, hot water heating operation, bath memorial operation, freeze prevention operation, circulation heating operation, etc.) are performed.

  The control unit 35 can perform data communication with the operation remote controller 36 that can be operated by the user. When various operations are set by operating the switch of the operation remote controller 36, the command signal is transmitted from the operation remote controller 36 to the control unit 35. Sent to. For example, when a target hot water set temperature (for example, 40 ° C.) is set by operating the switch of the operation remote controller 36, the target hot water set temperature data is transmitted from the operation remote controller 36 to the control unit 35.

Next, the circulating heating operation related to the present invention will be described.
The circulation heating operation that can be performed by the control unit 35 is performed by pumping before switching from the tank hot water discharged from the hot water storage tank 2 through the tank hot water discharge passage 22 to the auxiliary heating hot water discharged through the auxiliary heat source unit 3 during the hot water supply operation. By driving the pump 27 and the auxiliary heat source unit 3 to circulate hot water in the hot water going-out side passage portion 9a and the hot water return side passage portion 9b (heat utilization circulation passage), at least in the auxiliary heating passage 23 and the auxiliary heat source machine outlet passage 24. This is an operation for heating the hot water present inside (see FIG. 5).

  Next, the circulation heating operation control using the auxiliary heat source unit 3 and the pressure feed pump 27, which is automatically performed when switching from the tank hot water to the auxiliary heating hot water during the hot water supply operation, is based on the flowcharts of FIGS. explain. In the figure, the symbol Si (i = 1, 2,...) Indicates each step. A control program for hot water supply operation control including the circulating heating operation control is stored in the control unit 35 in advance.

  2 and 3, when this control is started, first, in S1, it is determined whether or not the hot water storage hot water supply apparatus 1 is in a hot water supply operation. When the hot water storage hot water supply apparatus 1 is in the hot water supply operation and is in the tank hot water discharging from the hot water storage tank 2 through the tank hot water discharge passage 22 (see the arrow in FIG. 4), that is, when the determination of S1 is Yes, the process proceeds to S2. If S1 is No, repeat S1.

  Next, in S2, a detection signal of the second hot water temperature detection sensor 2c from the top of the plurality of hot water temperature detection sensors 2a to 2d is read, and based on this detection signal, an upper portion (hot water temperature) in the hot water storage tank 2 is read. The upper hot water temperature Ta of the reservoir in the vicinity of the detection sensor 2c is calculated, and the process proceeds to S3.

  Next, in S3, it is determined whether or not the upper hot water temperature Ta in the hot water storage tank 2 is equal to or lower than the hot water supply set temperature T (for example, 40 ° C.), and the upper hot water temperature Ta in the hot water storage tank 2 is greater than the hot water supply set temperature T. When it is low, that is, when the determination of S3 is Yes, the process proceeds to S4, and when the upper hot water temperature Ta in the hot water storage tank 2 is higher than the hot water supply set temperature T, that is, when the determination of S3 is No, S2 and S3 are set. repeat.

  Next, in S4, it is determined whether or not the bath chase circuit 8 is in the freeze prevention operation. That is, when the outside air temperature decreases in a cold region or winter, the bath water in the bath remedy circuit 8 may be frozen and the piping may be damaged. Therefore, the bath circulator circuit 8c is driven to drive the bath remedy circuit 8 A freeze prevention operation (corresponding to a heat utilization terminal operation) is performed in which bathtub water is circulated to prevent freezing. When it is determined by the control unit 35 that the freeze prevention operation is being performed, that is, when the determination of S4 is Yes, the process proceeds to S5, and when the determination of S4 is No, the process proceeds to S6.

  Next, in S5, in order to temporarily stop the freezing prevention operation of the bath chase circuit 8, the driving of the bath circulation pump 8c is stopped, and the process proceeds to S6. That is, when the freeze-preventing operation is being performed in the heat-use heat exchanger 4 when the circulation heating operation is performed, the freeze-preventing operation is stopped during the circulation heating operation.

  Next, in S6, the circulating heating operation is started, and the process proceeds to S7. In S6, the three-way valve 26 is maintained on the heat utilization circulation circuit 9 side (tank hot water is maintained), the pressure pump 27 is driven, and combustion of the auxiliary heat source unit 3 is started. Thus, before switching from the tank hot water to the auxiliary heating hot water, the hot water is circulated in the heat utilization circulation circuit 9 partially including the auxiliary heating passage 23 and the auxiliary heat source machine hot water passage 24 to burn the auxiliary heat source device 3. The hot water in the heat utilization circuit 9 is heated in advance (see arrow in FIG. 5).

  Next, in S7, the detection signal of the hot water temperature detection sensor 3a is read, and based on this detection signal, the outlet hot water temperature Tb of the auxiliary heat source unit 3 derived from the outlet of the auxiliary heat source unit 3 is calculated. Migrate to

  Next, in S8, it is determined whether or not the outlet hot water temperature Tb of the auxiliary heat source unit 3 is equal to or higher than the hot water supply set temperature T + predetermined temperature α (for example, 40 ° C. + 5 ° C.), and the outlet hot water temperature Tb is determined as the hot water supply set temperature. It is determined whether or not the state of T + predetermined temperature α or more has continued for a predetermined time β (for example, about 10 to 30 seconds), and the outlet hot water temperature Tb of the auxiliary heat source unit 3 is higher than the hot water supply set temperature T + predetermined temperature α. And when it continues for a predetermined time β after the temperature rise, that is, when the determination of S8 is Yes, the process proceeds to S9, when the outlet hot water temperature Tb of the auxiliary heat source unit 3 is lower than the hot water supply set temperature T + the predetermined temperature α, If the determination at S8 is No, S7 and S8 are repeated.

  Next, in S9, the circulating heating operation is terminated, and the process proceeds to S10. In S10, the three-way valve 26 is maintained on the heat utilization circuit 9 side (tank hot water is maintained), the pressure pump 27 is stopped, the combustion of the auxiliary heat source unit 3 is stopped, and the freeze prevention operation is stopped in S5. Resumes the freeze prevention operation (see arrow in FIG. 4).

  Next, in S10, a detection signal of the uppermost hot water temperature detection sensor 2d among the plurality of hot water temperature detection sensors 2a to 2d is read, and an upper part (hot water temperature detection sensor in the hot water storage tank 2) is read based on this detection signal. The upper hot water temperature Tc of the reservoir in the vicinity of 2d is calculated, and the process proceeds to S11.

  Next, in S11, it is determined whether or not the upper hot water temperature Tc in the hot water storage tank 2 is equal to or lower than the hot water supply set temperature T (for example, 40 ° C.), and the upper hot water temperature Tc in the hot water storage tank 2 is greater than the hot water supply set temperature T. When it is low, that is, when the determination of S11 is Yes, the process proceeds to S12, and when the upper hot water temperature Tc in the hot water storage tank 2 is higher than the hot water supply set temperature T, that is, when the determination of S11 is No, S10, S11. repeat.

  Next, in S12, most of the hot water that can be supplied in the hot water storage tank 2 has been discharged, so an auxiliary heating operation is started in order to reheat the hot water, and the process proceeds to S13. In S13, the three-way valve 26 is switched to the auxiliary heating passage 22 side (switched from the tank hot water to the auxiliary heating hot water), the pressure feed pump 27 is driven, and combustion of the auxiliary heat source unit 3 is started (see arrow in FIG. 6).

  In S13, it is determined whether or not the hot water supply operation termination condition is satisfied. If the determination in S13 is No, the determination in S13 is repeated. If the determination in S13 is Yes, the process proceeds to S14 and the hot water supply operation is terminated.

Next, the operation and effect of the hot water storage and hot water supply apparatus 1 of the present invention will be described.
The control unit 35 constantly monitors the hot water supply state via various sensors such as the hot water temperature detection sensors 2a to 2d. If the heat utilization heat exchanger 4 is performing the heat utilization terminal operation (freezing prevention operation) before performing the circulation heating operation before switching from the tank discharge to the auxiliary heating discharge, the heat utilization terminal operation is performed. Is temporarily stopped during the circulating heating operation.

  Accordingly, since the hot water heated by the auxiliary heat source unit 3 in the circulation heating operation can be prevented from being radiated by the heat-use heat exchanger 4, it is possible to reliably prevent the occurrence of the cold water sandwich phenomenon, and the auxiliary hot water discharge from the tank hot water. The hot water heated by the auxiliary heat source unit 3 can be effectively supplied to the hot water supply passage 21 immediately after switching to, so that a decrease in the hot water discharge characteristic can be prevented.

  Furthermore, since the heat utilization terminal operation is a freeze prevention operation in which the heat radiation amount in the heat utilization heat exchanger 4 is particularly large, by stopping the heat utilization terminal operation during the simultaneous operation of the heat utilization terminal operation and the circulation heating operation, Cooling of the hot water heated by the auxiliary heat source unit 3 can be reliably prevented, and the occurrence of the cold water sandwich phenomenon can be more reliably prevented.

Next, a mode in which the above embodiment is partially changed will be described.
[1] The heat utilization terminal operation in the above embodiment need not be limited to the bath chase circuit 8, but may be a hot water heating circuit that circulates heating water supplied to a floor heating panel, a bathroom dryer or the like. These can be changed as appropriate.

[2] In the above-described embodiment, the three-way valve 26 is installed in the downstream heating passage portion 23b of the auxiliary heating passage 23, but is not particularly limited to this structure. You may install the three-way valve 26 in the branched part which branched.

[3] In the above-described embodiment, the hot water supply set temperature T and the predetermined temperature α are merely examples, and these temperatures can be changed as appropriate.

[4] In addition, those skilled in the art can implement the present invention by adding various modifications without departing from the spirit of the present invention, and the present invention includes such modifications. It is.

DESCRIPTION OF SYMBOLS 1 Hot water storage hot water supply equipment 2 Hot water storage tank 3 Auxiliary heat source machine 4 Heat utilization heat exchanger 21 Hot water supply passage 22 Tank hot water supply passage 23 Auxiliary heating passage 24 Auxiliary heat source machine hot water supply passage 26 Three-way valve (switching means)
27 Pressure pump (circulation means)
35 Control unit

Claims (2)

A tank hot water passage connected from the upper part of the hot water storage tank to the hot water supply passage, an auxiliary heating passage branched from the tank hot water supply passage and connected to the auxiliary heat source device, and an auxiliary heat source device connected from the auxiliary heat source device to the hot water supply passage A hot water passage, a switching means capable of switching between the tank hot water passage and the auxiliary heating passage, a circulation means installed in the auxiliary heating passage, and a branch from the auxiliary heat source machine hot water passage and connected to the auxiliary heating passage. A heat utilization circulation passage, and a heat utilization heat exchanger installed in the heat utilization circulation passage, and when the hot water temperature of the hot water storage tank becomes lower than a hot water supply set temperature, the switching means causes the tank discharge water passage to In the hot water storage hot water supply device that switches to the auxiliary heating passage,
Before switching from the tank hot water discharged from the hot water storage tank through the tank hot water outlet passage to the auxiliary heating hot water hot water discharged through the auxiliary heat source device, the circulation means and the auxiliary heat source device are driven to drive the heat utilization circulation passage. Control means capable of performing a circulating heating operation for heating hot water present in at least the auxiliary heating passage and the auxiliary heat source machine outlet hot water passage by circulating hot water into the hot water,
The control means stops the heat utilization terminal operation during the circulation heating operation when the heat utilization terminal operation is performed in the heat utilization heat exchanger when the circulation heating operation is performed. A hot water storage hot water supply device. The hot water storage hot-water supply apparatus according to claim 1, wherein the heat utilization terminal operation is a freeze prevention operation.