JP7329739B2 - Hot water storage water heater - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hot water storage and hot water supply apparatus that uses hot water stored in a hot water storage tank for hot water supply, and more particularly to a hot water storage and hot water supply apparatus that suppresses the growth of bacteria in the hot water storage tank.

Conventionally, a hot water storage and hot water supply apparatus that uses hot water stored in a hot water storage tank by hot water storage operation supplies clean water to which chlorine-based agents for sterilization etc. are added to the hot water storage tank, so bacteria grow in the hot water storage tank. There is little to do. However, if the hot water in the hot water storage tank continues to remain without being used, there is a non-zero possibility that various bacteria such as Legionella bacteria will proliferate. It is not hygienic to supply hot and cold water from a shower or the like, and there is a risk of harming health if germs are taken into the body.

Therefore, the hot water storage and hot water supply device counts the retention time of hot water in the hot water storage tank, sets a retention period that allows retention, and resets the retention time when all the hot water in the hot water storage tank is replaced within the retention period. is configured to Then, when the retention time exceeds the set retention period, an operation for preventing the proliferation of various germs is performed. The proliferation prevention operation is an operation of heating and sterilizing the entire amount of hot water in the hot water storage tank, or an operation of draining the entire amount of hot water in the hot water storage tank.

On the other hand, although it is not an operation to prevent the growth of various bacteria in a hot water storage tank for hot water supply, as in Patent Document 1, the risk of bacterial growth in a fuel cell water treatment device is calculated as a function of temperature and time, and the risk of bacterial growth is determined. A fuel cell power generation system is known that raises the water temperature when a threshold of is exceeded.

JP 2010-113885 A

Proliferation of various bacteria requires an appropriate temperature. For example, Legionella bacteria hardly grow in water with a temperature of less than 10°C, and are almost killed in water with a temperature of 60°C or more. In addition, when the hot water in the hot water storage tank is discharged, germs that may exist are discharged together, and fresh tap water is supplied accordingly, so that the growth of germs in the hot water tank is suppressed. In setting the residence period described above, no consideration is given to the temperature at which it is difficult to grow the water or the tap water, so the set residence period may be shorter than necessary.

Then, regardless of the temperature at which growth is difficult or the hot water to be discharged, if the retention time exceeds the set retention period, the growth prevention operation is performed, and the energy consumption increases due to heat sterilization, or the amount of hot water that is discharged is the amount of clean water. Since the amount used increases, it is not preferable from the viewpoint of saving resources. In addition, since the hot water storage and hot water supply device performs the multiplication prevention operation even though the hot water supply is not in use, the user of the hot water storage and hot water supply device may perceive it as a malfunction or malfunction of the hot water storage and hot water supply device. There is also a risk of giving

SUMMARY OF THE INVENTION An object of the present invention is to provide a hot water storage and hot water supply apparatus capable of appropriately performing a multiplication prevention operation.

The hot water storage and hot water supply apparatus of the invention of claim 1 comprises a hot water storage tank for storing hot water, a heating means for heating the hot water in the hot water storage tank, and a retention period in which the hot water in the hot water storage tank is preset. In a hot water storage and hot water supply apparatus comprising control means for performing a growth prevention operation to prevent the growth of various bacteria in the hot water storage tank when the temperature exceeds The control means determines whether the temperature detected by the temperature detection means is a high temperature range where bacteria do not grow, a medium temperature range where bacteria grow, or a low temperature range where bacteria growth is suppressed, A correction coefficient α (where 0≤α≤1) corresponding to the determined temperature range is set as a correction coefficient for correcting the residence time.

According to the above configuration, the temperature of the hot water in the hot water storage tank is set according to whether it is a high temperature range where bacteria do not grow, a medium temperature range where bacteria grow, or a low temperature range where bacteria growth is suppressed. The retention time is corrected by the correction coefficient , and when the corrected retention time exceeds the preset retention period, the proliferation prevention operation is performed. Therefore, the proliferation prevention operation can be appropriately executed according to the temperature of the hot water in the hot water storage tank. Then, an appropriate anti-proliferation operation can maintain a hygienic condition in the hot water storage tank and save resources.

According to a second aspect of the invention, there is provided a hot water storage and hot water supply apparatus according to the first aspect, wherein the temperature detection means comprises a plurality of temperature detection means for detecting hot water temperatures at a plurality of height positions of the hot water storage tank, and the control means comprises: a value obtained by dividing each of the plurality of correction coefficients α applied to the temperatures detected by the plurality of temperature detection means by the number of the temperature detection means, and setting a value obtained by summing a plurality of numerical values as a correction coefficient for correcting the residence time. It is characterized by
According to the above configuration, the plurality of temperature detection means are provided to detect the hot water temperature at the plurality of height positions of the hot water storage tank, and the control means adjusts the plurality of correction coefficients α applied to the detected temperatures to the temperature A value obtained by summing a plurality of numerical values divided by the number of detection means is set as a correction coefficient for correcting the dwell time, and the dwell time is corrected. Therefore, since the temperature distribution in the height direction of the hot water in the hot water storage tank can be reflected, the proliferation prevention operation can be executed more appropriately.

According to the hot water storage and hot water supply apparatus of the present invention, the proliferation prevention operation can be performed appropriately. Therefore, it is possible to maintain sanitary conditions in the hot water storage tank and save resources.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a configuration diagram of a hot water storage hot water supply apparatus according to Examples 1 to 3 of the present invention; 4 is an execution control flow chart of a proliferation prevention operation of the hot water storage and hot water supply apparatus according to Embodiments 1 and 2. FIG. 5 is a flow chart for setting a temperature correction coefficient α according to Example 1. FIG. 10 is a flow chart for setting a temperature correction coefficient α according to Example 2. FIG. 10 is an execution control flow chart of a proliferation prevention operation of the hot water storage and hot water supply apparatus according to Embodiment 3. FIG. FIG. 6 is a flowchart for setting a hot water correction coefficient β in FIG. 5; FIG.

Hereinafter, modes for carrying out the present invention will be described based on Examples 1 to 3.

First, the hot water storage and hot water supply device 1 will be described.
As shown in FIG. 1, a hot water storage and hot water supply apparatus 1 includes a hot water storage tank 2 for storing hot water, a heat source device 3 for circulating and heating the hot water in the hot water storage tank 2, and adjusting the temperature of hot water to be supplied. It has a mixing valve 4 for The hot water storage tank 2 is a cylindrical container provided with dish-shaped or semi-elliptical end plates at both ends (upper portion and bottom portion) so as to be sealed so as not to come into contact with the outside air.

A heat source machine forward passage 5 for supplying hot water to the heat source machine 3 is connected to the bottom of the hot water storage tank 2, and a heat source machine return passage for returning the hot water heated by the heat source machine 3 to the hot water storage tank 2 at the top of the hot water storage tank 2. 6 is connected. A heat source machine forward passage 5 is provided with a heat source machine forward temperature sensor 5 a for detecting the temperature of hot water supplied to the heat source machine 3 . A heat source return temperature sensor 6 a for detecting the temperature of hot water heated by the heat source device 3 is arranged in the heat source device return passage 6 .

The heat source device 3 is, for example, a heat pump type heat source device, and performs a hot water storage operation of heating and storing hot water in the hot water storage tank 2 . The heat source machine outgoing passage 5 is provided with a hot water storage pump 5b for sending hot water in the hot water storage tank 2 to the heat source machine 3 during the hot water storage operation. Note that the heat source device 3 may be provided with a hot water storage pump 5b, or the heat source device 3 may heat hot water using exhaust heat generated by a fuel cell, for example.

A water supply passage 7 for supplying tap water to the hot water storage tank 2 is connected to the bottom of the hot water storage tank 2 . A water supply temperature sensor 7a for detecting the temperature of tap water is provided in the water supply passage 7, and a water discharge passage 8 having a water discharge valve 8a is connected to the vicinity of the connection portion of the water supply passage 7 with the hot water storage tank 2. there is A hot water discharge passage 9 for discharging hot water from the hot water storage tank 2 is connected to the upper portion (top) of the hot water storage tank 2 .

A plurality of stored hot water temperature sensors 2a to 2e (temperature detecting means) are arranged in the hot water storage tank 2 at predetermined intervals in the height direction of the hot water storage tank 2 in order to detect the temperature of the hot water therein. are arranged. A tank outlet hot water temperature sensor 2f for detecting the temperature of the hot water discharged from the hot water storage tank 2 to the hot water outlet passage 9 (tank outlet) is arranged near the connecting portion of the hot water outlet passage 9 with the hot water storage tank 2. . The hot water storage tank 2, including the hot water temperature sensors 2a to 2e and the tank outlet hot water temperature sensor 2f, is covered with a heat insulating member (not shown) to prevent the hot water stored in the hot water storage operation from radiating heat and moderate the temperature drop.

The mixing valve 4 is connected to a first branch passage 10 branched from the water supply passage 7 , a hot water outlet passage 9 and a hot water supply passage 11 . The mixing valve 4 is configured to be able to adjust the mixing ratio of the high-temperature hot water supplied from the hot water discharge passage 9 and the low-temperature clean water supplied from the first branch passage 10 . The hot water mixed by the mixing valve 4 is supplied to the hot water supply passage 11 and supplied from the hot water tap 12 and the like.

A mixing valve inlet temperature sensor 9 a for detecting the temperature of the hot water supplied to the mixing valve 4 is arranged in the hot water outlet passage 9 near the high-temperature water inlet of the mixing valve 4 . The hot water supply passage 11 is provided with a hot water supply flow rate sensor 11a for detecting the hot water supply flow rate, a hot water supply temperature sensor 11b for detecting the hot water supply temperature, and a hot water supply flow rate adjustment valve 11c for adjusting the hot water supply flow rate.

A second branch passage 13 is further branched from the water supply passage 7, and the second branch passage 13 is connected to the reheating circulation passage 14 so that clean water can be supplied from the water supply passage 7 to the reheating circulation passage 14. It is The reheating circulation passage 14 includes an auxiliary heat source device 15 and a reheating heat exchanger 16, has a circulation pump 17 on the hot water inlet side of the auxiliary heat source device 15, and has an outlet side of the reheating heat exchanger 16. has an electromagnetic valve 18 for opening and closing the circulation passage 14 for reheating. The second branch passage 13 is connected between the circulation pump 17 and the solenoid valve 18 .

The reheating heat exchanger 16 is connected to a reheating passage 20 having a bathtub pump 19 for circulating hot water in a bathtub (not shown). The reheating heat exchanger 16 heats hot water in the bathtub flowing through the reheating passage 20 by heat exchange with hot water heated by the auxiliary heat source device 15 . The reheating passage 20 is connected to a hot water pouring passage 21 branched from the hot water supply passage 11 at the hot water supply flow rate adjustment valve 11c, and is configured to be able to pour hot water (filling) into the bathtub through the reheating passage 20. there is

Between the outlet of the circulation pump 17 of the reheating circulation passage 14 and the inlet of the auxiliary heat source device 15, an auxiliary heat source device inlet temperature sensor 14a for detecting the temperature of the hot water supplied to the auxiliary heat source device 15 and the flow rate of the auxiliary heat source device inlet temperature sensor 14a are provided. A circulation flow rate sensor 14b is provided for detection. An auxiliary heat source machine outlet temperature sensor 14c for detecting the temperature of hot water heated by the auxiliary heat source machine 15 is arranged in the reheating circulation passage 14 on the hot water outlet side of the auxiliary heat source machine 15 .

From the reheating circulation passage 14 between the auxiliary heat source unit outlet temperature sensor 14 c and the reheating heat exchanger 16 , an auxiliary hot water discharge passage 22 is branched and connected to the hot water discharge passage 9 . The auxiliary hot water outlet passage 22 is provided with a flow control valve 22a for adjusting the amount of hot water supplied to the hot water outlet passage 9 . The hot water heated by the auxiliary heat source machine 15 can be supplied to the hot water outlet passage 9 via the auxiliary hot water outlet passage 22 .

The hot water storage and hot water supply apparatus 1 includes a control unit 23 (control means) for controlling hot water supply operation, hot water storage operation, and the like. The control unit 23 controls equipment such as valves and pumps installed in each part based on the temperature detected by temperature sensors such as the hot water temperature sensor 2a and the flow rate detected by the hot water supply flow sensor 11a. It is operated to perform various operational controls. In addition, the control unit 23 has a timekeeping function and a function of learning and storing hot water supply usage history and the like. An operation terminal 24 having an operation unit and a display unit is connected to the control unit 23 in order to perform operation of the hot water storage and hot water supply apparatus 1 and various settings such as hot water supply set temperature. The display section of the operation terminal 24 displays information such as the set hot water supply temperature of the hot water storage and hot water supply apparatus 1 and the operation status.

Next, the hot water storage operation will be described.
The control unit 23 predicts the hot water supply time and the amount of hot water supply based on, for example, the learned and stored hot water supply history, and controls the hot water storage operation so that the hot water storage operation is completed just before the predicted hot water supply use. The controller 23 operates the hot water storage pump 5b and the heat source device 3 to start the hot water storage operation, and ends the hot water storage operation when the amount of heat corresponding to the predicted amount of hot water to be supplied is stored.

Next, the hot water supply operation will be described.
In the hot water supply operation in which hot water is supplied at the hot water supply set temperature, the control unit 23 adjusts the mixture ratio of the mixing valve 4 based on the temperatures detected by the mixing valve inlet temperature sensor 9a, the water supply temperature sensor 7a, and the hot water supply temperature sensor 11b. Hot water adjusted to the set temperature of hot water supply is supplied by this. At this time, the controller 23 performs the hot water supply operation using the hot water stored in the hot water storage tank 2 by the hot water storage operation. In the hot water supply operation, the controller 23 controls the hot water supply time (hot water supply usage time), the hot water supply flow rate detected by the hot water supply flow rate sensor 11a, the hot water supply usage time, the hot water supply flow rate, and the hot water supply tank 2 calculated from the mixing ratio of the mixing valve 4. It learns and stores the history of hot water supply usage, including the amount of hot water supplied.

When the hot water stored in the hot water supply is used up during the hot water supply operation, or when there is no hot water of a temperature that can be used for hot water supply in the hot water storage tank 2, the control unit 23 drives the circulation pump 17 to supply water from the water supply passage 7. A hot water supply operation is performed using hot water obtained by heating the supplied tap water with an auxiliary heat source machine 15.例文帳に追加Also, for example, when hot water is supplied at a higher temperature than the stored hot water by changing the set temperature of the hot water supply, the control unit 23 uses hot water obtained by heating the clean water supplied from the water supply passage 7 by the auxiliary heat source device 15. hot water supply operation.

Next, the growth of various germs in the hot water storage tank 2 will be explained.
The hot water storage tank 2 is filled with tap water supplied from the water supply passage 7 and stores hot water heated by the hot water storage operation. The growth of various germs in the hot water storage tank 2 requires a temperature suitable for growth. For example, Legionella bacteria double every 4 to 6 hours in a temperature range of about 20 ° C to 45 ° C suitable for growth, growth is suppressed at low temperatures below 10 ° C, and at temperatures higher than 60 ° C in a short time. known to die.

Since the tap water is added with a chlorine-based agent for sterilization, when the hot water storage tank 2 is filled with fresh tap water, there is almost no bacteria in the hot water storage tank 2, and there is a fear that bacteria may proliferate due to retention. Almost none. However, the possibility of the presence of germs is not zero, and the residual chlorine concentration in the stagnant tap water gradually decreases. In particular, when the water is heated to a temperature of less than 60° C. by the hot water storage operation, the temperature becomes suitable for growth, and the possibility of the growth of various bacteria further increases.

Here, since it is generally difficult to count the total number of proliferating bacteria, the number of proliferating bacteria is expressed using a colony forming unit (CFU), which counts the number of colonies formed when the bacteria are cultured. Since the possibility of Legionella spp. existing in the hot water storage tank 2 is not zero, it is assumed that the minimum 1 [CFU] of Legionella spp. , a retention period for which retention is permitted is set in advance to, for example, 100 hours. The control unit 23 measures (counts) the retention time of hot water in the hot water storage tank 2, and when the retention time exceeds a preset retention period, the control unit 23 performs a growth prevention operation to prevent the growth of various bacteria in the hot water storage tank 2. conduct. When the entire amount of hot water in the hot water storage tank 2 is replaced within a preset retention period, the next retention period is measured without performing the multiplication prevention operation.

Next, the proliferation prevention operation will be described.
The growth prevention operation is an operation of heating and sterilizing the entire amount of hot water in the hot water storage tank 2 (full amount heat sterilization operation) or an operation of draining the entire amount of hot water in the hot water storage tank 2 (full amount draining operation). In the case of carrying out the total heat sterilization operation as the proliferation prevention operation, the entire amount of hot water in the hot water storage tank 2 is heated to a temperature higher than 60° C. (for example, 65° C.) and sterilized.

When heating is performed using the auxiliary heat source device 15 as a heating means, the circulation pump 17 is driven to supply the accumulated hot water from the bottom of the hot water storage tank 2 to the auxiliary heat source device 15, and the hot water is heated to a temperature higher than 60°C. Hot water is returned to the upper part of the hot water storage tank 2 through the auxiliary hot water discharge passage 22 and the hot water discharge passage 9. - 特許庁When the temperature detected by the auxiliary heat source inlet temperature sensor 14a becomes higher than 60° C. and all the hot water in the hot water storage tank 2 is heat sterilized, the heat sterilization operation is completed. When heating is performed using the heat source device 3 as the heating means, it is the same as the hot water storage operation in which hot water is stored at a temperature higher than 60°C, and the detected temperature of the heat source device outgoing temperature sensor 5a becomes higher than 60°C and the hot water storage tank is closed. When the entire amount of hot water in 2 is heat sterilized, the entire amount heat sterilization operation is completed.

In the case where the operation for preventing the growth of water is configured to perform a full water discharge operation, for example, a water supply valve (not shown) that opens and closes the water supply passage 7 is closed, the water discharge valve 8a of the water discharge passage 8 is opened, and the hot water storage tank 2 is drained. is done. After the hot water storage tank 2 is completely drained, the drain valve 8a is closed and the water supply valve is opened to fill the hot water storage tank 2 and the drained passage with clean water, thus completing the full drain operation.

The counting of the retention time by the controller 23 is started when the hot water storage tank 2 is in a state (retention state) in which there is no hot water discharge from the tank and the hot water storage operation is not performed. Execution control of the proliferation prevention operation based on the counting of the residence time by the control unit 23 will be described below with reference to the flow charts of FIGS. 2 and 3. FIG. Si (i=1, 2, . . . ) in the figure represents steps.

Here, an example will be described in which, as a fixed cycle time, the residence time is counted at t=4 hours for one cycle during which the number of bacteria doubles. It is assumed that 1 [CFU] of various germs is present in the hot water storage tank 2 at the start of counting the residence time.

There is no hot water discharge from the hot water storage tank 2 and the hot water storage operation is not performed. It includes a state of waiting for the hot water supply operation after completion, and a state of waiting after the previous anti-proliferation operation is completed. If this staying state continues for a long time, there is a risk that bacteria will grow in the hot water storage tank 2. Therefore, the staying time of the hot water in the hot water storing tank 2 is counted, and when the staying time exceeds the preset staying period, Perform anti-proliferation actions.

First, in S1, it is determined whether or not the hot water storage and hot water supply device 1 is in a stagnant state. If the determination is Yes, go to S2 to start counting the residence time. If the determination is No, the determination of S1 is repeated. The determination in S1 is performed periodically at appropriate intervals, but may be performed each time the operation state of the hot water storage and hot water supply apparatus 1 changes (for example, the hot water storage operation or the hot water supply operation is stopped).

Next, in S2, the retention time count N and the accumulated amount of hot water discharged from the tank Q after the start of counting the retention time are initialized to zero, the counting of the retention time is started, and the process proceeds to S3. Then, in S3, time is counted until the time t of one cycle has passed, and the process proceeds to S4. Note that the tank hot water integrated amount Q after the start of counting the residence time is calculated based on the hot water supply use history learned and stored by the control unit 23 .

In S4, it is determined whether or not the accumulated hot water output Q from the start of counting the residence time to the present is smaller than the capacity of the hot water storage tank 2 (tank capacity V). It is determined whether or not the entire amount of hot water has been replaced. If the determination in S4 is Yes, that is, if they have not been replaced, the process proceeds to S5. If the determination in S4 is No, the entire amount of hot water in the hot water storage tank 2 has been replaced, so the multiplication prevention operation is not performed, and the process proceeds to S9 to finish counting the residence time and return.

Next, in S5, in order to reflect the temperature of the hot water in the hot water storage tank 2 in counting the residence time, a temperature correction coefficient α is set based on the temperatures detected by the stored hot water temperature sensors 2a to 2e. As shown in FIG. 3, when the setting of the temperature correction coefficient α is started, it is determined in S11 whether or not the minimum temperature of hot water in the hot water storage tank 2 (tank minimum temperature) is higher than 60.degree. When the minimum tank temperature is higher than 60°C, the counting of the retention time is started after the hot water storage operation at a temperature higher than 60°C is completed, or the counting of the retention time is started after the previous proliferation prevention operation is completed. A hot water storage operation at a temperature higher than 60° C. that was started later may be completed. If the determination in S11 is Yes, the temperature is high enough to kill germs, so the process proceeds to S12, sets α=0, and then proceeds to S6 in FIG.

On the other hand, if the determination in S11 is No, the process advances to S13 to determine whether or not the maximum temperature of hot water in the hot water storage tank 2 (tank maximum temperature) is lower than 10°C. A case where the maximum tank temperature is less than 10°C means a case where the hot water storage tank 2 is almost filled with clean water having a temperature lower than 10°C and the hot water storage operation is not performed, or a case where the hot water stored in the hot water is not in operation after the retention time starts counting. This is the case, for example, when hot water of a temperature lower than 10° C. is filled. If the determination in S13 is Yes, the temperature is low enough to suppress the growth of various germs to some extent, so the process proceeds to S14, sets α=0.5, for example, and then proceeds to S6 in FIG. If the determination in S13 is No, there is a risk of proliferation of various bacteria, so the process proceeds to S15, sets α=1, and then proceeds to S6 in FIG.

Next, in S6 of FIG. 2, the staying time is counted and the process proceeds to S7. Each time the residence time count N is counted, a value corrected by the temperature correction coefficient α (maximum 1, minimum 0) is added.

Next, in S7, it is determined whether or not the product of the time t of one cycle and the retention time count N, that is, the retention time corrected according to the temperature of hot water in the hot water storage tank 2 has exceeded a preset retention period. do. If the determination is Yes, the process proceeds to S8 for proliferation prevention operation. If the determination is No, the process returns to S3 to continue counting the residence time.

At this time, at a temperature that suppresses the growth of various germs, it takes a long time to double. Reflecting this, the increase in the residence time count N is moderated to shorten the residence time, so that the start timing of the proliferation prevention operation is postponed and the preset residence period is substantially extended. In this manner, the residence time is corrected by reflecting the possibility of proliferation at the time t of one cycle according to the temperature of the hot water in the hot water storage tank 2, so that it is possible to appropriately determine whether to perform the proliferation prevention operation.

Next, in S8, a proliferation prevention operation is executed. When the proliferation prevention operation is completed, the process advances to S9 to finish counting the residence time and returns. If the hot water storage operation is being performed when the proliferation prevention operation is executed, the hot water storage operation is stopped and the proliferation prevention operation is performed.

Further, when the hot water supply operation is performed by discharging hot water from the hot water storage tank 2 at the time of execution of the proliferation prevention operation, the proliferation prevention operation is performed after the hot water supply operation is finished. At this time, the auxiliary heat source device 15 is switched to a hot water supply operation in which tap water is heated and hot water is supplied, and hot water supply is continued until the hot water supply operation ends. The hot water in the hot water storage tank 2 may continue to be supplied as it is, but in this case, after the hot water supply operation ends, the proliferation prevention operation is executed by determining whether or not the entire amount of hot water in the hot water storage tank 2 has been replaced. It is preferable to determine whether to

An example in which the setting of the temperature correction coefficient α in the first embodiment is partially changed will be described with reference to the flow charts of FIGS. 2 and 4. FIG.
In S5 of FIG. 2, when the setting of the temperature correction coefficient α is started, in S21 of FIG. 4, the temperature correction coefficients corresponding to the plurality (here, five) of the stored hot water temperature sensors 2a to 2e are set, and the process proceeds to S22. . The temperature correction coefficient is set to a value according to the detected temperature. Then, in S22, a value obtained by summing the temperature correction coefficients set for each of the plurality of stored hot water temperature sensors 2a to 2e is set as the temperature correction coefficient α, and then the process proceeds to S6 in FIG.

At this time, the temperature correction coefficients α1 to α5 are set according to the detected temperatures of the five hot water storage temperature sensors 2a to 2e, and the total value of α1 to α5 (temperature correction coefficient α) is 1 at maximum and 0 at minimum. I'm trying For example, α1 to α5 are set to 0.1 if the detected temperature is less than 10°C, 0.2 if the detected temperature is between 10°C and 60°C, and 0 if the detected temperature is higher than 60°C.

Depending on the setting of α1 to α5, if part of the stored hot water with a temperature higher than 60°C is not discharged and remains, or if the water supply temperature is less than 10°C, the hot water that remains due to the hot water storage operation. The temperature distribution of the hot water in the hot water storage tank 2, such as when a portion is heated, can be reflected in the temperature correction coefficient α. Then, reflecting the fact that it takes a long time to double at a temperature that suppresses the growth of various bacteria, the increase in the retention time count N is moderated to make the retention time shorter than it actually is. In this way, since the retention time is corrected according to the temperature detected by the hot water storage temperature sensors 2a to 2e, execution of the proliferation prevention operation can be determined more appropriately.

An example in which the retention time is corrected based on the amount of hot water discharged from the tank in addition to the correction of the retention time based on the temperature in the first and second embodiments will be described with reference to the flow charts of FIGS. 5 and 6. FIG.
Since S1 to S5 in FIG. 5 are the same as those in FIG. 2, their description is omitted. After setting the temperature correction coefficient α in S5, the process proceeds to S30 to set the hot water correction coefficient β based on the amount of hot water discharged from the tank.

Here, as shown in FIG. 6, when setting of hot water correction coefficient β is started, in S31, residual rate r of hot water in hot water storage tank 2 is set, and the process proceeds to S32. This residual rate r is the ratio of hot water remaining without being discharged from the hot water storage tank 2 of tank capacity V during the time t of one cycle, and is obtained by using the amount q of hot water discharged from the tank during the time t of one cycle. , r=1−q/V. The tank hot water amount q is calculated from the hot water supply usage history learned and stored by the control unit 23 .

Next, in S32, after setting the outlet hot water correction coefficient β based on the residual rate r, the process proceeds to S40 in FIG. The discharged hot water correction coefficient β can express, for example, that during the time t of one cycle in which the mixed bacteria can double, bacteria that may exist are discharged and reduced according to the amount q of discharged hot water from the tank. is set to Here, β=-log ₂ (r), which is calculated based on the residual rate r, that is, the amount of hot water discharged from the tank q. Alternatively, the outlet hot water correction coefficient β may be set based on a correspondence table between the outlet hot water amount q and the hot water correction coefficient β held in the control unit 23 in advance.

After setting the hot water correction coefficient β, the residence time is counted in S40, and the process proceeds to S41. A value corrected by a temperature correction coefficient α is added to the residence time count N, and a hot water supply correction coefficient β is subtracted. For example, half of the tank capacity V (q=V/2) is discharged during the time t of one cycle during which germs can double, and half of the germs that may exist in the hot water storage tank 2 are discharged. In this case, the hot water correction coefficient β becomes 1 and the staying time count N is decremented by 1. This reflects that one cycle worth of proliferation was suppressed.

Next, in S41, it is determined whether or not the staying time count N is a negative (minus) value. If the determination is Yes (N<0), the process proceeds to S42, in which the residence time count N is set to zero, and the process proceeds to S43. If the determination is No, the process proceeds to S43. This is because it is assumed that the minimum number of germs present in the hot water storage tank 2 is 1 [CFU] at the start of counting the residence time (when N=0).

Next, in S43, it is determined whether the staying period is exceeded. It is determined whether or not the product of the time t of one cycle and the dwell time count N, that is, the corrected dwell time exceeds the preset dwell period. Since the residence time is corrected by the correction according to the temperature of the hot water in the hot water storage tank 2 and the correction according to the amount of hot water discharged from the tank q, it is possible to more appropriately determine whether the multiplication prevention operation should be executed. If the determination is Yes, the process proceeds to S44 to execute the proliferation prevention operation. Then, after the growth prevention operation is completed, the process proceeds to S45, where the counting of the residence time is terminated and the process returns. If the determination is No, the process returns to S3 to continue counting the residence time.

The operation and effect of the hot water storage and hot water supply apparatus 1 of the first to third embodiments will be described.
The hot water storage and hot water supply device 1 includes a hot water storage tank 2 for storing hot water, heating means (heat source device 3 and auxiliary heat source device 15) for heating the hot water in the hot water storage tank 2, and the retention time of the hot water in the hot water storage tank 2. A control unit 23 is provided to perform a growth prevention operation to prevent the growth of various germs in the hot water storage tank 2 when a preset retention period is exceeded. The hot water storage tank 2 includes hot water temperature sensors 2a to 2e that detect the temperature of the hot water in the hot water storage tank 2, and the controller 23 controls the hot water in the hot water storage tank 2 according to the temperature detected by the hot water temperature sensors 2a to 2e. correct the time.

Therefore, when the temperature is high enough to kill germs in the hot water storage tank 2, or when the temperature is low enough to suppress the growth of germs, the retention time is corrected, and when the corrected retention time exceeds the retention period, the growth prevention operation is performed. Therefore, the proliferation prevention operation can be properly executed according to the hot water temperature in the hot water storage tank 2 . Therefore, consumption of clean water and energy can be suppressed while maintaining a sanitary condition in the hot water storage tank 2 .

A plurality of stored hot water temperature sensors 2a to 2e are arranged in the height direction of the hot water storage tank 2, and the control unit 23 corrects the residence time according to the temperatures detected by the plurality of stored hot water temperature sensors 2a to 2e. Therefore, when part of the hot water stored at a temperature higher than 60°C remains without being discharged, or when the water supply temperature is below 10°C, part of the retained hot water is heated by the hot water storage operation. It is possible to reflect the temperature distribution in the hot water storage tank 2, such as when it is hot, so that the proliferation prevention operation can be performed more appropriately.

The control unit 23 corrects the residence time according to the amount of hot water stored in the hot water storage tank 2 (the amount of hot water discharged from the tank q). Therefore, it is possible to reflect that the germs assumed to exist in the hot water storage tank 2 are reduced by the amount of hot water discharged from the hot water storage tank 2, and the proliferation prevention operation can be executed more appropriately.

Since the growth prevention operation is an operation for heating and sterilizing the entire amount of hot water stored in the hot water storage tank 2 or an operation for draining the entire amount of the hot water stored in the hot water storage tank 2, by heating and sterilizing the entire amount of hot water in the hot water storage tank 2 or by replacing the entire amount, the inside of the hot water storage tank 2 can supply hot water while maintaining the sanitary condition of

The control unit 23 can also appropriately perform the proliferation prevention operation by correcting the residence period instead of correcting the residence time. For example, the temperature of the hot water and the amount of hot water discharged from the hot water storage tank 2 can be preset according to the correction of dividing the residence period by the temperature correction coefficient α or the correction of adding the product of the hot water discharge correction coefficient β and the time t to the residence period. Correct to extend the residence period. Also in this case, similarly to the above, the proliferation prevention operation can be appropriately executed according to the temperature of the hot water in the hot water storage tank 2 and the amount of hot water discharged.

In addition, those skilled in the art can implement various modifications to the above embodiment without departing from the spirit of the present invention, and the present invention includes such modifications.

1: Hot water storage and hot water supply device 2: Hot water storage tanks 2a to 2e: Hot water storage temperature sensor (temperature detection means)
2f: Tank hot water temperature sensor 3: Heat source device (heating means)
4: Mixing valve 5: Passage 5a for heat source machine: Temperature sensor 5b for heat source machine: Hot water storage pump 6: Heat source machine return passage 7: Water supply passage 7a: Water supply temperature sensor 8: Drain passage 8a: Drain valve 9: Hot water outlet passage 10: First branch passage 11: Hot water supply passage 11a: Hot water supply flow rate sensor 13: Second branch passage 14: Reheating circulation passage 15: Auxiliary heat source machine (heating means)
17: Circulation pump 20: Reheating passage 21: Pouring passage 22: Auxiliary hot water discharge passage 23: Control section (control means)

Claims (2)

a hot water storage tank for storing hot water, a heating means for heating the hot water in the hot water storage tank, and germs in the hot water storage tank when a retention time of the hot water in the hot water storage tank exceeds a preset retention period. In a hot water storage and hot water supply device equipped with control means for performing a growth prevention operation to prevent the growth of
The hot water storage tank includes temperature detection means for detecting the temperature of hot water in the hot water storage tank,
The control means determines whether the temperature detected by the temperature detection means is a high temperature range in which bacteria do not grow, a medium temperature range in which bacteria grow, or a low temperature range in which the growth of bacteria is suppressed. A hot water storage and hot water supply apparatus characterized in that a correction coefficient α (0≦α≦1) corresponding to a temperature range is set as a correction coefficient for correcting the residence time. The temperature detection means comprises a plurality of temperature detection means for detecting the temperature of hot water at a plurality of height positions of the hot water storage tank, and the control means comprises a plurality of correction coefficients applied to the temperatures detected by the plurality of temperature detection means. 2. The hot water storage and hot water supply apparatus according to claim 1, wherein a value obtained by summing a plurality of numerical values obtained by dividing .alpha. by the number of said temperature detection means is set as a correction coefficient for correcting said residence time.