JP2018162911A - Hot water storage and hot water supply device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hot water storage and hot water supply device capable of shortening a time required for heating sterilization treatment of hot water in a hot water storage tank where Legionella or the like proliferates, to reduce energy consumption, thereby improving efficiency.SOLUTION: A hot water storage and hot water supply device is configured to, when hot water in a hot storage tank is accumulated for a fixed period or more, heat the hot water by heating means through a circulation heating circuit, to perform sterilization operation. In the hot water storage tank, provided are a plurality of temperature detection means configured to detect a hot water temperature in the hot water storage tank. In the sterilization operation, the hot water storage and hot water supply device is configured to control circulation means to: perform circulation at a predetermined circulation flow rate at the initial stage of operation; and adjust a circulation flow rate according to a hot water temperature state in the hot water storage tank detected by the temperature detection means.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a hot water storage and hot water supply apparatus that shortens the time required for the heat sterilization treatment of hot water in a hot water storage tank in which Legionella bacteria and the like are propagated, thereby reducing energy consumption and improving efficiency.

  Conventionally, hot water storage devices with high energy efficiency that can store hot water heated by an external heat source device such as a heat pump water heater or a fuel cell in a hot water storage tank and supply the stored hot water to a hot water supply destination have been widely used. ing. Such a hot water storage hot water supply apparatus includes an external heat source device, a hot water storage tank for storing hot water heated by the external heat source device, a hot water circulation circuit for circulating hot water between the external heat source device and the hot water storage tank, and the like. Hot water in the tank is circulated in a hot water circulation circuit and heated by an external heat source device, and the heated hot water is returned to and stored in a hot water storage tank and supplied to a desired hot water supply destination such as a hot water tap or a bathtub.

  In the above hot water storage and hot water supply apparatus, when hot water in the hot water storage tank is not used for a long time, since hot water in the hot water storage tank is contaminated with bacteria such as Legionella bacteria, it cannot be supplied to the hot water or bathroom as it is. For this reason, in order to kill these miscellaneous bacteria, the sterilization process which reheats the hot water in the hot water storage tank is performed.

  Sterilization is performed by repeatedly removing hot water from the lower part of the hot water storage tank and heating it with an auxiliary heat source device installed in the hot water storage hot water supply system, returning the hot water to the upper part of the hot water storage tank. It is reheated to about 75 ° C or higher.

  Usually, when it is determined that the hot water in the hot water storage tank is not used for a certain time or longer (for example, 100 hours or longer), the sterilization treatment is performed, but until all the hot water in the hot water storage tank is heated to a high temperature, In principle, the use of hot water in hot water storage tanks is prohibited. For this reason, during the sterilization process, the supply path from the hot water storage tank to the hot water supply or hot water filling is cut off to restrict the use to the hot water supply or hot water filling.

  Therefore, in order to finish the sterilization treatment as soon as possible, it is conceivable to circulate at a large flow rate, heat the auxiliary heat source machine, and return from the upper part in the hot water storage tank. However, when heated hot water is injected at a large flow rate from the upper part of the hot water storage tank, the hot water in the hot water storage tank is agitated and the temperature stratification formed in the hot water storage tank 5 is destroyed. If the temperature stratification formed in the hot water tank collapses, a part of the hot water in the hot water tank partially remains at a low temperature, and it takes a considerable amount of time to sterilize the entire hot water in the hot water tank to 70 ° C or higher. It was.

  On the other hand, in order to perform sterilization while maintaining the temperature stratification of the hot water in the hot water storage tank, it is conceivable to circulate at a circulation flow as small as possible. However, even in the case of a small circulation flow rate, it takes time to reheat the entire hot water in the hot water storage tank, and during that time, the use of the hot water in the hot water storage tank for hot water supply or hot water filling is restricted, which is inconvenient for the user. Will be forced.

  Patent Document 1 discloses a cogeneration apparatus that can use hot water supply even during sterilization treatment of Legionella bacteria or the like. According to this apparatus, if there is a hot water supply request after the sterilization conditions are established and the use of hot water in the hot water storage tank is prohibited, the hot water in the hot water storage tank is once heated and sterilized by the auxiliary heat source machine. It is used for hot water supply without returning to In addition, the amount of outflow from the hot water storage tank after the sterilization treatment conditions are established is integrated, and if the integrated value exceeds the hot water storage tank capacity, the sterilization treatment conditions are canceled and the normal hot water supply operation is resumed. This prevents unnecessary heat treatment by the machine.

Japanese Patent Laid-Open No. 2006-156559

  However, the cogeneration apparatus that performs the sterilization process of Patent Document 1 is applicable only when there is a hot water supply request in a situation where sterilization process conditions are established and the use of hot water in the hot water storage tank is prohibited, In the first place, it was not intended to end the sterilization of hot water in the hot water storage tank early, and the time required for the sterilization could not be shortened.

  Also, if the accumulated amount exceeds the hot water storage tank capacity after the sterilization treatment conditions are established and the accumulated value exceeds the hot water storage tank capacity, the sterilization treatment conditions are canceled and the normal hot water supply operation is resumed. When the capacity of the hot water storage tank is not large enough, the hot water is forcibly discharged, and the hot water in the hot water storage tank is filled with new water supply to finish the sterilization process quickly, resulting in waste of resources. The energy consumption cannot be reduced.

  An object of the present invention is to provide a hot water storage hot water supply apparatus that shortens the time required for the heat sterilization treatment of hot water in a hot water storage tank in which Legionella bacteria and the like are bred, reduces energy consumption, and improves efficiency.

  The hot water storage and hot water supply apparatus according to claim 1 is a hot water storage tank for storing hot water, a heating means for heating the hot water, and a circulating heating circuit for taking out the hot water from the lower part of the hot water storage tank and heating it to the upper part of the hot water storage tank. And a circulating means provided in the circulation heating circuit, and when the hot water in the hot water storage tank stays for a certain period of time or longer, the hot water storage apparatus performs heating and sterilization operation by the heating means through the circulation heating circuit. The hot water storage tank is provided with a plurality of temperature detection means for detecting the temperature of the hot water in the interior, and in the sterilization operation, the circulation means is controlled so as to circulate at a predetermined circulation flow rate at the beginning of the operation. At the same time, the circulation means is controlled so as to adjust the circulation flow rate according to the hot water temperature inside the hot water storage tank detected by the temperature detection means. It is characterized in that.

According to a second aspect of the present invention, there is provided the hot water storage hot water supply apparatus according to the first aspect of the invention, wherein the temperature detection means is a temperature detection means provided at an upper portion of the hot water storage tank among a plurality of temperature detection means, and the upper portion of the hot water storage tank. When it is detected that the hot water temperature is equal to or higher than the sterilization temperature, the circulation means is changed and controlled to increase the circulation flow rate.
A hot water storage hot water supply apparatus according to a third aspect is characterized in that, in the invention according to the first or second aspect, the heating means is a combustion type instantaneous hot water supply apparatus.

  According to the first aspect of the present invention, in the sterilization operation, the circulation means is controlled to circulate at a predetermined circulation flow rate at the beginning of operation, and the hot water temperature inside the hot water storage tank detected by the temperature detection means is determined. Therefore, since the change control of the circulation means is performed so as to adjust the circulation flow rate, the sterilization operation can be performed without destroying the temperature stratification of the hot water formed in the hot water storage tank.

  That is, at the beginning of the sterilization operation, the circulating means is controlled so that the hot water taken out from the lower part of the hot water tank is circulated at a circulating flow rate of, for example, 5 l / min, so the hot water heated by the heating means is supplied from the upper part of the hot water tank. Even if it returns, it is only poured into the hot water of the relatively high temperature layer in the hot water storage tank, and the low temperature layer is not stirred and the temperature stratification does not collapse.

  And if a certain time has passed since the start of the sterilization operation and the hot water temperature inside the hot water tank detected by the predetermined temperature detecting means exceeds, for example, 70 ° C., the high temperature layer in the hot water tank spreads to some extent, The circulation means is changed and controlled so that the circulation flow rate is increased little by little (for example, 1 liter per minute). For this reason, by increasing the circulating flow rate as the hot layer in the hot water tank gradually spreads, the entire hot water in the hot water tank is reheated and the sterilization operation can be performed in a short time without destroying the temperature stratification. Can be terminated.

  According to the invention of claim 2, the predetermined temperature detecting means is constituted by a temperature detecting means provided at an upper portion of the hot water storage tank among the plurality of temperature detecting means, and is detected by the temperature detecting means at the upper portion. When it is detected that the temperature, that is, the upper hot water temperature of the hot water storage tank is higher than the sterilization temperature (for example, 70 ° C. or higher), the circulation means is changed and controlled so as to increase the circulation flow rate. It can be gradually expanded downward from the upper part of the hot water tank, reheating the entire hot water in the hot water tank in a short time while gradually increasing the circulation flow rate without destroying the temperature stratification formed in the hot water tank, The time required for the sterilization treatment can be shortened.

  According to the invention of claim 3, since the heating means is a combustion type instantaneous hot water supply device, it is possible to prevent the hot water temperature after heating from becoming low even when the circulation flow rate fluctuates. Other effects similar to those of the first aspect are obtained.

It is the schematic of the heat pump hot-water supply apparatus of this invention. It is a schematic block diagram of the hot water storage hot-water supply apparatus of this invention. It is a flowchart of system trial run control.

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

The overall configuration of the heat pump hot water supply apparatus 1 will be described.
As shown in FIGS. 1 and 2, the heat pump hot water supply apparatus 1 has a hot water storage hot water supply unit 2 having an auxiliary heat source unit 4 and a heat pump heat source unit 3, and the hot water storage hot water supply unit 2 and the heat pump heat source unit 3 have a heating circuit 10. Connected through.

First, the hot water storage hot water supply unit 2 will be described.
As shown in FIG. 2, the hot water storage hot water supply unit 2 is connected to the auxiliary heat source unit 4, a hot water storage tank 5 for storing hot water, a hot water passage 6 connected to the upper end of the hot water tank 5, and a hot water passage 6. A hot water supply passage 7 for supplying hot water to a hot water supply destination, a pouring passage 8 that branches from the hot water supply passage 7 and fills the bathtub 15, a bath memorial passage 9 for heating the hot water from the bathtub 15, and hot water storage A heating circuit 10 that circulates the hot water in the tank 5 so as to be heated by the heat pump heat source unit 3 and stored in the hot water storage tank 5, a water supply passage 13 that supplies the hot water to the hot water storage tank 5, and a mixture that mixes the hot water and the hot water A valve 14, a heat exchanger 12 provided in the bath chase passage 9, a control unit 11 for performing various controls, an operation remote controller 41, and the like are provided.

  A plurality of temperature sensors 5 a to 5 d are provided at appropriate intervals in the vertical direction on the side of the hot water storage tank 5 to detect the temperature for each temperature stratification of the hot water stored in the hot water storage tank 5. In order to prevent the temperature of the stored hot water from dropping, the periphery of the hot water storage tank 5 is covered with a heat insulating material (not shown).

Next, the heating circuit 10 that connects the hot water storage hot water supply unit 2 and the heat pump heat source unit 3 will be described.
The heating circuit 10 includes a forward passage portion 10a, a return passage portion 10b, and a bypass passage portion 10c that connects them. The upstream passage 10 a has an upstream end connected to the lower end of the hot water storage tank 5, and a downstream end connected to the condensing heat exchanger 37 in the heat pump heat source unit 3. The return passage portion 10 b has an upstream end connected to the condensation heat exchanger 37 and a downstream end connected to the upper end portion of the hot water storage tank 5.

  A circulation pump 18 is interposed in the middle of the forward passage 10a, and a circulation temperature sensor 10d is provided in the middle of the return passage 10b. A switching three-way valve 19 is interposed at a connection point between the forward passage portion 10a and the bypass passage portion 10c. By switching the switching three-way valve 19, it is possible to switch between the bypass passage 10c side and the hot water storage tank 5 side. When the switching three-way valve 19 is switched to the bypass passage 10c side, the hot water heated by the heat pump heat source unit 3 is sent back to the heat pump heat source unit 3 again without returning to the hot water storage tank 5, and is reheatable.

  The heat pump heat source unit 3 is controlled by the control unit 11 via the auxiliary control unit 35, and the compressor 36, the condensation heat exchanger 37, the expansion valve 38, and the evaporating heat exchanger 39 are connected by the refrigerant pipe 40, thereby forming a heat pump circuit. Is a device that heats hot and cold water using the refrigerant enclosed in the refrigerant pipe 40 and the heat of the outside air.

Next, the water supply passage 13 will be described.
The water supply passage 13 supplies low-temperature clean water from a clean water source to the hot water storage tank 5 and the like, and has an upstream end connected to the clean water source and a downstream end connected to the lower end of the hot water storage tank 5. A water supply bypass passage 22 is branched from the water supply passage 13 and connected to the mixing valve 14. A water supply temperature sensor 23 is provided in the water supply passage 13, a water supply opening / closing valve 24 is provided upstream of the branch portion, a check valve 25 is provided downstream of the branch portion, and the water supply bypass passage 22 is reversely connected. A stop valve 26 is provided. A high temperature hot water avoidance passage 28 branched from the water supply bypass passage 22 and connected to the hot water supply passage 7 is provided so as to avoid high temperature hot water unexpected by the user.

Next, the hot water supply passage 6 and the hot water supply passage 7 will be described.
The hot water outlet passage 6 has an upstream end connected to the upper end portion of the hot water storage tank 5, a downstream end connected to the mixing valve 14, and the hot water supply passage 7 connected to the mixing valve 14. The mixing valve 14 is supplied from the water supply bypass passage 22 to supply hot water at a hot water supply set temperature set by the user via the operation remote controller 41 to the hot water supply passage 7 or to supply hot water at the hot water supply set temperature to the bathtub 15. The mixing ratio of the low temperature clean water to be supplied and the high temperature hot water supplied from the hot water outlet passage 6 is adjusted. Hot water adjusted to the hot water supply set temperature is supplied from the hot water supply passage 7 to the hot water tap. The hot water supply passage 7 is provided with a hot water temperature sensor 30 and a hot water flow rate sensor 31 that can detect the hot water temperature and the hot water flow rate adjusted by the mixing valve 14, and detect the hot water temperature and the hot water flow rate.

Next, the pouring passage 8 will be described.
An on-off valve 8a is provided in the pouring passage 8 branched from the hot water passage 7 and filling the bathtub 15, and the downstream end of the pouring passage 8 is connected to a bath passage portion 9a described later. In order to supply hot water at a hot water supply set temperature set via the operation remote controller 41 to the bathtub 15, hot water from the upper part of the hot water storage tank 5 flows to the mixing valve 14 through the hot water supply passage 6, and the water supply bypass passage 22 in the mixing valve 14. The hot water is mixed with the water from above and flows into the pouring passage 8 as hot water having a hot water supply set temperature, and is supplied to the bathtub 15 through the on-off valve 8a and the bath passage passage portion 9a.

Next, the bath remedy passage 9 and the heat exchanger 12 for bath remedy will be described.
The heat exchanger 12 heats the hot water in the bathtub 15 by heat exchange between the hot water flowing through the additional hot water passage 21 connected to the downstream portion of the auxiliary hot water passage 20 e and the hot water flowing through the bath additional passage 9. An open / close valve 21a is provided in the remedy hot water passage 21 and is closed so that hot water does not flow into the heat exchanger 12 except during bath remedy operation.

  The bath memorial passage 9 circulates the hot water in the bathtub 15 and heats it in the heat exchanger 12. The bath passage passage portion 9 a for sending the hot water heated by the heat exchanger 12 to the bathtub 15, It has a bath return passage portion 9b provided with a memory pump 16 for sending hot water to the heat exchanger 12. The bath-out passage portion 9a includes a bath-out temperature sensor 9c that detects the temperature of hot water in the bathtub 15 after heat exchange, and the bath return passage portion 9b includes a memorial pump 16, a bath return temperature sensor 9d, and a bathtub. A water level sensor 9e for detecting 15 water levels is provided.

  The hot water return passage 21 b to which the downstream end of the memorial hot water passage 21 is connected is connected to the downstream portion of the water supply passage 13. An upper auxiliary passage 20a for supplying hot water to the auxiliary heat source unit 4 is branched from the hot water supply passage 6 and connected to the three-way valve 27, and a lower auxiliary passage 20b for supplying low-temperature hot water or clean water to the auxiliary heat source unit 4 Is extended from the hot water return passage 21 b and connected to the three-way valve 27, and the auxiliary introduction passage 20 c extending from the three-way valve 27 is connected to the auxiliary heat source unit 4.

  A circulation pump 34 is interposed in the auxiliary introduction passage 20c. The auxiliary hot water passage 20e through which hot hot water heated by the auxiliary heat source unit 4 is discharged is connected to the hot water passage 6 upstream of the mixing valve 14, and a circulation temperature sensor 32 and a flow rate adjustment valve 33 are provided in the auxiliary hot water passage 20e. It is intervened. The three-way valve 27 is configured to be selectively switchable between the hot water storage tank 5 side and the lower auxiliary passage 20b side. The circulation pump 34 corresponds to “circulation means”.

Next, the auxiliary heat source unit 4 will be described.
The auxiliary heat source unit 4 is composed of a known combustion type instantaneous hot water supply device (gas water heater) incorporating a burner, a heat exchanger, etc., and hot water flowing into the auxiliary introduction passage 20c after being combusted by a command from the control unit 11 Can be heated. The hot water heated by the auxiliary heat source unit 4 flows through the auxiliary hot water passage 20e and is supplied to the hot water passage 6. The auxiliary heat source unit 4 corresponds to “heating means”.

The auxiliary heat source unit 4 is used when the hot water in the hot water storage tank 5 is sterilized.
Specifically, when the sterilization operation is performed, the three-way valve 27 is switched to the lower auxiliary passage 20b side, and the circulation pump 34 is operated so that the low-temperature hot water in the hot water storage tank 5 is supplied to the lower auxiliary passage 20b and the auxiliary introduction passage 20c. It introduces to auxiliary heat source machine 4 through. The hot water heated to the high temperature by the auxiliary heat source device 4 is returned to the upper part of the hot water storage tank 5 through the auxiliary hot water passage 20e and the hot water passage 6 in order. The circulation heating circuit 20 is formed by a circulation circuit constituted by a part of the lower auxiliary passage 20b, the auxiliary introduction passage 20c, the auxiliary hot water passage 20e, and the hot water passage 6, and the circulation heating circuit 20 corresponds to the “circulation heating circuit”. To do.

Next, the control unit 11 will be described.
The control unit 11 acquires the temperature and flow rate of each part by the temperature sensors 5a to 5d, the circulating temperature sensors 10d and 32, the feed water temperature sensor 23, the hot water supply temperature sensor 30, the other hot water supply flow rate sensors 31, and the like, and the switching three-way valve 19 , The mixing valve 14, the three-way valve 27, the flow rate adjustment valve 33, other valves, the remedy pump 16, the circulation pumps 18, 34, etc. are operated, and the heat pump heat source unit 3 is heated to operate at the hot water supply set temperature. Control hot water storage operation, hot water supply operation, etc. so that tension and hot water supply are performed. Further, when it is detected that the hot water in the hot water storage tank 5 has not been used for a long time, the sterilization processing operation of the hot water in the hot water storage tank 5 described later is controlled.

Next, the sterilization processing operation performed in the heat pump hot water supply apparatus 1 will be described.
In the sterilization treatment operation, when the hot water in the hot water storage tank 5 stays for a certain time (for example, 100 hours) or more, the hot water in the hot water storage tank 5 may be contaminated by breeding bacteria such as Legionella. It is prohibited to use the hot water in the hot water storage tank 5 for hot water supply or hot water filling as it is. Therefore, low-temperature hot water is circulated from the lower part of the hot water storage tank 5 and heated by the auxiliary heat source device 4 through the circulation heating circuit 20, and reheated so that the entire hot water in the hot water storage tank 5 becomes about 70 ° C. or higher. In addition, various bacteria such as Legionella are sterilized by heating.

  Specifically, the three-way valve 27 is switched to the lower auxiliary passage 20b side, the circulation pump 34 is operated, and the hot water that is a low temperature layer in the hot water storage tank 5 is connected to the lower portion of the hot water storage tank 5 The hot water heated by the auxiliary heat source unit 4 is introduced into the auxiliary heat source unit 4 through the auxiliary passage 20b and the auxiliary introduction channel 20c in order, and the hot water stored in the hot water storage tank 5 through the auxiliary hot water passage 20e and the outlet channel 6 in this order. By flowing into the upper part, the hot water in the hot water storage tank 5 is reheated.

  At this time, when the circulation heating circuit 20 is circulated at the maximum circulation flow rate from the beginning and reheated by the auxiliary heat source unit 4 and returned to the upper part of the hot water storage tank 5, the hot water in the hot water storage tank 5 is agitated and temperature stratified. As a result, the hot water in the hot water storage tank 5 partially remains at a low temperature, and in this state, it takes a long time to reheat so that the entire hot water becomes about 70 ° C. or higher.

  For this reason, at the beginning of the sterilization operation, the circulation heating circuit 20 is circulated at a small circulation flow rate (for example, 5 l / min), reheated by the auxiliary heat source unit 4 and returned to the upper part in the hot water storage tank 5, When it is detected that the temperature detected by the upper temperature sensor 5c provided in the hot water storage tank 5 is equal to or higher than the sterilization temperature (for example, 70 ° C. or higher), the circulation flow rate is increased so as to increase by 1 liter per minute, for example. The circulation pump 34 corresponding to the means is changed and controlled. With this control, the high temperature layer in the hot water storage tank 5 can be gradually expanded downward from the upper part of the hot water storage tank 5, and the temperature stratification formed in the hot water storage tank 5 is not destroyed, and the hot water storage tank 5 The entire hot water is reheated to shorten the time required for sterilization.

  At this time, the control of the sterilization processing operation by the heat pump hot water supply apparatus 1 executed by the control unit 11 will be briefly described based on the flowchart of FIG. In the flowchart, Si (i = 1, 2,...) Represents each step.

  First, when it is determined in the control unit 11 that hot water in the hot water storage tank 5 has stayed for a certain time (for example, 100 hours) or longer, a sterilization treatment operation for reheating the hot water in the hot water storage tank 5 for Legionella bacteria countermeasures is performed. Start.

  In S1, it is determined that no hot water supply or additional cooking is being performed. If the determination is Yes, the process proceeds to S2, and if the determination is No, the process returns to repeat the determination in S1. Next, it is determined in S2 that the heating operation is not performed. If the determination is Yes, the process proceeds to S4, and if the determination is No, the process proceeds to S3 to simultaneously perform reheating and heating operation in the hot water storage tank 5. The control to be performed is executed, and the process returns to S1.

Here, when the determination of S1 and S2 is Yes, the hot water supply, the additional cooking operation, and the heating operation are not performed, and the hot water in the hot water storage tank 5 remains, so the circulation flow rate is adjusted from S4. Control processing is performed.
In S4, the circulation pump 34 is controlled so that the circulation flow rate becomes 5 l / min, the circulation heating circuit 20 is circulated, and the auxiliary heat source unit 4 performs reheating to heat the hot water in the hot water storage tank 5.

  Next, in S5, it is determined whether or not the temperature of the second temperature sensor 5c of the hot water storage tank 5 is 70 ° C. or higher. If the determination is Yes, the process proceeds to S6. In S6, it is determined whether or not a continuous flow rate of 5 l / min has elapsed for 60 seconds. If Yes, the process proceeds to S7. In S7, it is determined whether or not the temperature sensor 5c has detected a temperature of 70 ° C. or more for 10 seconds or more. If Yes, the process proceeds to S8, and the circulation pump 34 is changed to increase the circulation flow rate by 1 l / min. Control is processed. On the other hand, if the determinations in S5 to S7 are No, it is not yet the timing to increase the circulation flow rate from 5 l / min, so the process returns to S1.

  After increasing the circulating flow rate by 1 l / min in S8, the process proceeds to S10 to determine whether or not only the sterilization operation is operated alone. If Yes, the process proceeds to S11. If No, the process returns to S1. That is, when operation such as hot water supply or additional cooking other than the sterilization operation is performed and hot water in the hot water storage tank 5 is supplied, the sterilization operation such as Legionella bacteria is in a standby state, and thus the sterilization process is continued. Instead of continuing the operation, the process returns to S1 to return to the initial state, and the sterilization operation is restarted.

  Next, in S11 to S13, after the circulation flow rate is increased by 1 l / min, the same determination as in S5 to S7 is performed. If S11 to S13 are all Yes, the process proceeds to S14 and the circulation flow rate is 8 l / min or more. It is determined whether or not. If the determination in S14 is No, the process returns to S8, the circulation flow rate is increased by 1 l / min, and the processes in S10 to S14 are repeated.

  On the other hand, when S11 is No, it progresses to S9, it is determined whether the temperature of the 2nd temperature sensor 5c is 70 degrees C or less continuously for 15 seconds, and when it is Yes, the hot water in the hot water storage tank 5 is determined. Since no reheating is performed, the process returns to S1 and returns to the initial state.

  Next, when the determination of S14 is Yes, that is, when it is determined that the circulating flow rate is 8 l / min or more, the process proceeds to S15 to determine whether or not the hot water storage tank 5 is fully charged. Do. When the determination of S15 is Yes, the sterilization processing operation by reheating the hot water in the hot water storage tank 5 is terminated, and when No, the processing of S10 to 14 is repeated.

The effect of the heat pump hot water supply apparatus will be described.
In the sterilization treatment operation, at the beginning of the operation, the circulation pump 34 is controlled to circulate at a predetermined circulation flow rate (for example, 5 l / min), and the hot water temperature inside the hot water storage tank 5 detected by the second temperature sensor 2c. Since the change control of the circulation pump 34 is performed so as to adjust the circulation flow rate according to the situation, the sterilization operation can be performed without destroying the temperature stratification of the hot water formed in the hot water storage tank 5.

  That is, at the beginning of the sterilization treatment operation, the circulating pump 34 is controlled so that the hot water taken out from the lower part of the hot water storage tank 5 is circulated at a circulating flow rate of 5 l / min, for example. Even if it returns from the upper part of the hot water storage tank 5, it is only poured into the hot water in the hot upper layer in the hot water storage tank 5, and the low temperature layer is not stirred and the temperature stratification does not collapse.

  When a certain time has elapsed from the start of the sterilization treatment operation and the hot water temperature in the hot water storage tank 5 detected by the second temperature sensor 2c exceeds, for example, 70 ° C., the high temperature layer in the hot water storage tank 5 spreads to some extent. Therefore, the circulation pump 34 is changed and controlled so that the circulation flow rate is gradually increased from 5 l / min (for example, 1 liter per minute). For this reason, the entire hot water in the hot water storage tank 5 is reheated and sterilized without increasing the temperature stratification by increasing the circulating flow rate as the high temperature layer in the hot water storage tank 5 gradually spreads. It can be completed in a short time.

  Further, when it is detected that the temperature detected by the second temperature sensor 2c provided at the upper part of the hot water storage tank 5 among the plurality of temperature sensors 5a to 5d is 70 ° C. or higher, the circulation flow rate is set to 1 per minute. Since the circulation pump 34 is changed and controlled so as to increase by 1 liter, the high temperature layer in the hot water storage tank 5 can be gradually expanded downward from the upper part of the hot water storage tank 5, and the temperature stratification formed in the hot water storage tank 5 is destroyed. Instead, the entire hot water in the hot water storage tank 5 can be reheated in a short time while increasing the circulation flow rate little by little, and the time required for the sterilization treatment can be shortened.

  In the said Example, although the case where 70 degreeC or more was detected by the temperature of the 2nd 2nd temperature sensor 5c provided in the hot water storage tank 5 from the top was demonstrated to an example, it is not limited to this. For example, the temperature sensor to be detected may be configured to be changeable depending on the situation such as when the hot water storage tank has a large diameter or has a height.

  In addition, the said Example is only an example, and those skilled in the art can implement in the form which added the various change to the said Example, without deviating from the meaning of this invention, and this invention is such. Various modifications are also included.

DESCRIPTION OF SYMBOLS 1 Heat pump hot water supply apparatus 2 Hot water storage hot water supply unit 3 Heat pump heat source machine 4 Auxiliary heat source machine 5 Hot water storage tank 5a-5d Temperature sensor 10 Heating circuit 11 Control unit 20a Upper auxiliary passage 20b Lower auxiliary passage 20c Auxiliary introduction passage 20e Auxiliary hot water passage 34 Circulation pump

Claims (3)

A hot water storage tank for storing hot water, a heating means for heating the hot water, a circulating heating circuit that takes hot water from the lower part of the hot water tank and heats it back to the upper part of the hot water tank by the heating means, and is provided in the circulating heating circuit In the hot water storage hot water supply apparatus that performs sterilization operation by heating with the heating means through the circulation heating circuit when the hot water in the hot water storage tank stays for a certain time or longer,
The hot water storage tank is provided with a plurality of temperature detection means for detecting the temperature of the hot water in the interior, and in the sterilization operation, the circulation means is controlled so as to circulate at a predetermined circulation flow rate at the beginning of the operation. In addition, the hot water storage hot water supply apparatus is characterized in that the circulation means is changed and controlled so as to adjust the circulation flow rate in accordance with the hot water temperature condition inside the hot water tank detected by the temperature detection means.   The temperature detection means is a temperature detection means provided at an upper part of the hot water storage tank among a plurality of temperature detection means, and circulates when it is detected that the upper hot water temperature of the hot water storage tank is equal to or higher than the sterilization temperature. The hot water storage hot water supply apparatus according to claim 1, wherein the circulation means is changed and controlled so as to increase a flow rate. The hot water storage hot water supply apparatus according to claim 1 or 2, wherein the heating means is a combustion type instantaneous hot water supply apparatus.