JP4715401B2 - Hot water storage water heater - Google Patents

Description

  The present invention relates to a hot water storage type hot water supply apparatus, and particularly to hot water mixing control using an electric mixing valve.

  Conventionally, this type of hot water storage type hot water supply device stores hot water heated by a heat pump circuit in a stratified state from the upper part of the hot water storage tank, and the hot water stored in the hot water storage tank is taken out from the upper hot water discharge pipe and mixed with the water supplied from the water supply pipe. Then, it is adjusted to a predetermined hot water temperature and supplied to a load side such as a hot water supply terminal. Further, in recent years, hot water storage type hot water supply devices having a function of using this hot water storage for bathing and heating are drawing attention. However, in this case, the hot water whose temperature has dropped after being used for bathing or heating is collected again in the hot water storage tank, so the hot water inside the hot water tank is called halfway hot water below the upper hot water. A large amount of hot and cold water will be stored. When the whole amount boiling operation is performed in a state where the medium-temperature water is stored, the heating operation of the heat pump cycle is performed in a state where the incoming water temperature to the heat pump circuit is high. Become.

Therefore, as disclosed in Patent Document 1, as disclosed in Patent Document 1, an intermediate temperature water outlet is provided in the middle portion of the hot water storage tank, and the intermediate temperature water extracted from the outlet and the high temperature water extracted from the upper outlet pipe are disposed. A predetermined hot water temperature is ensured by mixing, and the mixed water and water supplied from a water supply pipe are mixed to obtain hot water at a set temperature with high accuracy. According to this method, the medium-temperature water can be actively taken out, so that low-temperature water can be secured below the hot water tank, and the use of high-temperature water above the hot water tank can be minimized. It is possible to suppress the boiling operation of the COP and the phenomenon of running out of hot water.
JP 2003-240342 A

  However, according to the above conventional configuration, in the hot water supply apparatus using the heat pump circuit, by providing means for using the medium temperature water preferentially in order to eliminate the influence on the boiling performance of the medium temperature water, Can secure low-temperature water, minimize the use of high-temperature water above the hot water storage tank, and can control the boiling operation of high COP and the phenomenon of running out of hot water. Although this is an extremely effective means of using hot water in the equipment, the use of hot water in the hot water storage tank has been stagnant for a long time in situations where the hot water usage in the hot water storage tank is extremely small or not used at all. If the temperature of hot water in the hot water storage tank decreases, miscellaneous germs may grow.In particular, Legionella germs may harm the human body. . This Legionella bacterium is actively active in the range of hot water temperature of 25 ° C. to 50 ° C., and this hot water temperature range is a phenomenon that tends to occur in the lower part of the hot water storage tank when the amount of hot water used is extremely small. In such a state, if hot water is supplied using the means for using medium-temperature water, the proliferated bacteria such as Legionella bacteria are actively supplied to the user terminal, which has a problem in terms of hygiene.

  The present invention solves the above-described conventional problems, and provides a hot and cold water mixing control method capable of preferentially using medium-temperature water, which is an extremely effective means for using hot water in a heat pump type hot water supply apparatus, The purpose of the present invention is to provide a hot water storage type hot water supply device that ensures safety when the use of hot water stagnate in situations where the amount of hot water used is extremely small.

In order to solve the above-mentioned conventional problems, the hot water storage type hot water supply apparatus of the present invention stores hot water heated using a heat pump circuit in a stratified state from the upper part of the tank and supplies desired hot water to the terminal side using the hot water. In the hot water storage type hot water supply apparatus, a hot water outlet pipe for taking out hot water at the upper part of the tank, an intermediate hot water hot pipe for taking out hot water at an approximately middle part of the tank, an intermediate temperature detecting means for detecting the hot water temperature in the tank near the intermediate hot water hot pipe, Upper temperature detecting means for detecting the hot water temperature in the tank between the intermediate hot water discharge pipe and the upper hot water discharge pipe, a first mixing valve for mixing hot water from the hot water discharge pipe and the intermediate hot water discharge pipe, and hot water from the first mixing valve A use side mixing valve that mixes water from the water supply pipe and supplies hot water of a predetermined temperature to the terminal side, and a controller that controls the opening degree of the first mixing valve and the use side mixing valve. Set up time zone In addition, the hot water storage type hot water supply device is set to perform the hot water boiling operation when it is determined that the hot water amount is insufficient, and the control unit detects the middle temperature detection means during the time period when the full water heating operation is performed. When the hot water temperature is 30 ° C. or higher and the hot water temperature detected by the upper temperature detecting means is 45 ° C. or higher for a predetermined time, the first mixing valve is fully opened to the outlet pipe side. It is made to drive so that it may become.

  According to the above invention, it is determined whether or not intermediate temperature water exists in the hot water storage tank by the intermediate temperature detection means, and whether or not a hot water replacement phenomenon has occurred by using the high temperature water at the upper part of the hot water storage tank by the upper temperature detection means. As a hot water usage form after the amount of hot water in the hot water storage tank is less than the result of both judgments, and hot water of medium temperature or lower stays in the lower part of the hot water tank for a long time, hot water is supplied from the medium temperature hot water pipe. Since the control of the first mixing valve is prohibited so that it does not occur, there is medium hot water, the amount of hot water used is low, the hot water in the hot water tank is stagnant, and the temperature drops at the lower part of the hot water tank Even if miscellaneous bacteria such as Legionella propagate, they can be used from the relatively hot water in the upper part of the hot water storage tank, and hot water can be supplied without being affected by the bacteria.

  The hot water storage type hot water supply apparatus of the present invention provides a hot water mixing control method capable of preferentially using medium hot water, which is a very effective means as a hot water use form of a heat pump type hot water supply apparatus, and uses the amount of hot water in the hot water storage tank. Therefore, it is possible to provide a hot water storage type hot water supply apparatus that ensures safety when the use of hot water is stagnant in a situation where the amount of water is extremely small.

A first invention is a hot water storage type hot water supply apparatus that stores hot water heated using a heat pump circuit in a stratified state from the upper part of a tank and supplies the desired hot water to the terminal side using the hot water. A hot water pipe, an intermediate temperature hot water pipe for taking out hot water at a substantially middle part of the tank, an intermediate temperature detecting means for detecting the hot water in the tank in the vicinity of the intermediate temperature hot water pipe, and the hot water in the tank between the intermediate temperature hot water pipe and the upper hot water pipe Upper temperature detecting means for detecting water, a first mixing valve for mixing hot water from the outlet hot water pipe and the intermediate hot water hot water pipe, hot water from the first mixing valve and water from the water supply pipe are mixed, and hot water at a predetermined temperature is mixed. A use side mixing valve that supplies the terminal side to the terminal side, and a control unit that controls the opening degree of the first mixing valve and the use side mixing valve, and sets a time zone for performing a full-boiling operation, and the amount of hot water is insufficient When judging the hot water boiling A hot water storage type hot water supply apparatus was set to perform a raising operation, the control unit, in a time zone performing total volume boiling operation, the and the hot water detected by the central temperature detecting means 30 ° C. or higher, and The hot water temperature detected by the upper temperature detecting means is driven so that the first mixing valve is fully opened to the side of the hot water pipe when the hot water temperature is 45 ° C. or higher for a predetermined time. is there.

  Then, the middle temperature detecting means determines whether or not the medium temperature water exists in the hot water storage tank, and the upper temperature detecting means determines whether or not the hot water replacement phenomenon has occurred due to the use of the high temperature water in the upper part of the hot water storage tank. As a result of the above judgment, the amount of hot water in the hot water storage tank is small, and hot water supply from the intermediate temperature hot water pipe is not performed as a hot water usage form after the hot water of medium temperature or lower has stagnated for a long time below the hot water storage tank. Since the control of the first mixing valve is prohibited, there is medium-temperature water, the amount of hot water used is low, the hot water in the hot water tank is stagnant, the temperature drops at the bottom of the hot water tank, and Legionella bacteria, etc. Even if miscellaneous bacteria propagate, it can be used from the relatively hot water at the upper part of the hot water storage tank, and hot water can be supplied without being affected by the miscellaneous bacteria.

  In addition, the control unit is characterized in that the first mixing valve is fully opened and the hot water supply from the intermediate temperature hot water pipe is prohibited.

  When the hot water usage prohibition mode is present in which there is medium hot water and the amount of hot water used is small, the hot water side is fully opened so that hot water is supplied only from the hot water discharge pipe at the top of the tank. Therefore, it is possible to suppress the supply of miscellaneous bacteria propagated in the lower part of the hot water storage tank to the user terminal. In other words, since the hot water supply from the middle temperature hot water pipe near the bottom of the hot water storage tank, where the temperature distribution is easy for breeding of bacteria, is prohibited, the bacteria will not be supplied to the terminal on the user side and above the medium temperature hot water pipe. A predetermined amount of hot and cold water can be ensured by using a relatively high temperature hot water that is difficult for the bacteria to propagate and adjusting to a desired hot water temperature using a use-side mixing valve.

  In the second aspect of the invention, the control unit returns the hot water / water mixing control of the first mixing valve when it is confirmed that the whole amount boiling operation has been completed under a predetermined boiling condition.

  Then, during the midnight hours after it is determined that the medium hot water usage mode is low, and the amount of hot water used is low, the entire amount of the hot water tank is heated up, and the temperature of the hot water at the bottom of the hot water tank When the temperature to die, for example, 65 ° C., is restored to perform normal hot water mixing control, medium temperature water is present, and miscellaneous bacteria that proliferated during a period when the amount of hot water used is extremely low, After that, effective hot water supply can be performed by hot water mixing control that preferentially uses medium-temperature water in a safe state.

  According to a third aspect of the present invention, the control unit returns the hot water / water mixing control of the first mixing valve after a time zone for performing the hot water boiling operation after the time zone of the first full-boiling operation has elapsed. It is a thing.

  Then, when the medium temperature water is present and the amount of hot water used is small, the medium temperature water use prohibited mode is entered. Then, after the first night time period has elapsed, the first mixing valve is reached. In the medium warm water use prohibit mode, the control of the first mixing valve is prohibited and the supply of hot water from the medium temperature hot water pipe is prohibited. It is possible to prevent the outflow of various bacteria such as Legionella that propagated in the lower part of the hot water tank during periods when the amount of water used is extremely low. Can be boiled to a temperature of 65 ° C or higher, and after the total boiling time has elapsed, hot water mixing control is performed using the control of the first mixing valve, so that various bacteria such as Legionella Does not exist It is possible to ensure an effective hot water use form.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
FIG. 1 is a configuration diagram of a hot water storage type hot water supply apparatus according to a first embodiment of the present invention.

The hot water storage tank 101 is provided with a boiling pipe 102 in which a lower part and an upper part are communicated with each other, and a boiling pump 103 and a heat exchanger 104 are provided in the middle thereof. The water in the lower part of the hot water storage tank 101 is guided to the heat exchanger 104 by the boiling pump 103 through this boiling path, and heated in the process of passing through the heat exchanger 104 to become hot water, and is guided to the upper part of the hot water storage tank 101. The hot water supplied to the hot water storage tank 101 is accumulated in layers in the hot water storage tank 101 in such a manner that the hot water is separated into the upper part and the water is separated into the lower part due to the difference in specific gravity. When the hot water in the hot water storage tank 101 is used, water is supplied from the water supply pipe 105 into the hot water storage tank 101, and the hot water reduced in accordance with the use state is placed in the hot water storage tank 101 at the upper part. The water supplied from 105 is stored in a separated state at the bottom.

  The heat pump circuit 106 serving as a heat source for the heat exchanger 104 is composed of a compressor 107, an expansion valve 108, and a forced air-cooled evaporator 110 using a fan 109. Carbon dioxide is used as a refrigerant, and a critical pressure is set on the high-pressure side. It is possible to store hot water close to 90 ° C. by operating in a temperature exceeding that, and hot water storing about 65 ° C. considering Legionella bacteria can be performed at a high COP.

  Next, a use side circuit configuration for supplying hot water in the hot water storage tank 101 to the load side will be described. A hot water discharge pipe 111 for taking out high temperature water is provided at the upper part of the hot water storage tank 101, and the hot water discharge pipe 111 and the water supply pipe 105 are provided. An intermediate hot water discharge pipe 112 for taking out the medium-temperature water is provided at a substantially intermediate portion.

  A bath utilization circuit 116 connected to a lower part of the hot water storage tank 101 through a circulation pump 115 is provided from the hot water outlet pipe 111 to a bath heat exchanger 114 for exchanging heat with hot water in the bathtub 113 and performing a reheating operation. On the secondary side of the bath heat exchanger 114, a bath circulation circuit 119 is connected to the bath adapter 117 of the bathtub 113 and the bath pump 118 circulates the bath water. With the above configuration, the hot water supplied from the upper part of the hot water storage tank 101 is heat-exchanged with the bath water flowing through the bath circulation circuit 119 by the bath heat exchanger 114 and the temperature is lowered, and then returned to the hot water storage tank 101 as intermediate hot water. . If this bath chasing operation continues, the amount of high-temperature water in the upper part of the hot water storage tank 101 decreases and the amount of medium-temperature water accumulated below it increases. This increase phenomenon of intermediate temperature water causes various adverse effects, and is largely related to a decrease in the operating efficiency (COP) of the heat pump circuit 106 during the boiling operation. That is, when the medium temperature water is increased in the lower part of the hot water storage tank 101, heat exchange with the refrigerant of the heat pump circuit 106 is performed in a state where the incoming water temperature of the heat exchanger 104 at the time of boiling is high, and the temperature difference between the refrigerant and the hot water decreases. Heating capacity is reduced. In particular, in a heat pump cycle using carbon dioxide as a refrigerant, since the high-pressure side pressure of the heat pump is high, the degree of decrease in the operating efficiency (COP) of the heat pump becomes significant when the incoming water temperature increases.

  Further, the increase in the medium-temperature water means that the high-temperature water in the upper part of the hot water storage tank 101 is reduced, and the hot water storage capacity is lowered as a whole, leading to a shortage of hot water.

  Therefore, in the present embodiment, as a countermeasure against the warm water, an intermediate hot water pipe 112 is provided at a substantially intermediate portion of the hot water storage tank 101, and hot water supplied from the intermediate hot water pipe 112 and the upper hot water pipe 111 is mixed to obtain a predetermined mixed water. The first mixing valve 120 is provided to obtain the desired temperature, and the valve opening is adjusted by feeding back the hot water temperature detected by the first temperature detector 121 to ensure a predetermined target temperature. By providing the first mixing valve 120, it is possible to preferentially take out the hot water according to the purpose of use, and the hot water in the hot water storage tank 101 can be reduced.

  On the output side of the first mixing valve 120, a load-side circuit corresponding to the application is configured. First, as hot water use, the mixed water from the first mixing valve 120 and the water from the water supply pipe 105 are mixed to set the set temperature. A hot water supply mixing valve 122 which is one of the load side mixing valves for obtaining hot water is provided and supplied to the currant 124. A hot water temperature detector 123 is attached to the output side of the hot water mixing valve 122, and the valve opening is adjusted by feeding back the hot water temperature detected by the hot water temperature detector 123 so as to ensure a set temperature. Yes.

For bath use, a bath mixing valve 125 is provided as one of the load side mixing valves for mixing the mixed water from the first mixing valve 120 and the water from the water supply pipe 105 to obtain hot water at a set temperature. The bath is connected to the bath circulation circuit 119 via the pouring valve 126 to fill the bathtub 113 with hot water. A bath temperature detector 127 is attached to the output side of the bath mixing valve 125. By adjusting the valve opening by feeding back the hot water temperature detected by the bath temperature detector 127, the set temperature is secured. Yes.

  Note that a check valve 128 is provided in the high temperature water side supply path of the first mixing valve 120 so as to prevent the back flow of the medium temperature water from the intermediate tapping pipe 112. In addition, check valves 129 and 130 are provided in the hot water supply path of the hot water supply mixing valve 122 and the bath mixing valve 125, and a check valve 131 is provided on the output side of the hot water supply mixing valve 122.

  A hot water remote controller 132 is provided in the vicinity of the currant 124, and a bath remote controller 133 is provided in the bathroom. The operation instruction from the hot water remote controller 132 or the bath remote controller 133 is sent wirelessly or by wire to a control unit 134 provided on the apparatus body side, and various operations are performed based on the control operations previously defined by the control unit 134 according to the transmitted conditions. I try to do it.

  In addition, the control unit 134 is provided with a timer unit 140 with a calendar function that measures 24 hours, and the timer unit 140 performs a full-time boiling operation, that is, a midnight power period (for example, 23:00) ~ 7 o'clock) and the daytime time zone (7 o'clock to 23 o'clock) in which the hot water boiling operation is performed.

  The hot water storage type hot water supply apparatus in the present embodiment is configured to boil the entire amount of the hot water storage tank 101 in accordance with a heating mode preset in a midnight power time zone (for example, from 23:00 to 7:00) by a boiling circuit 102 as shown in FIG. The amount of remaining hot water decreases and the amount of hot water decreases based on the temperature detected by the remaining hot water temperature detectors 135, 136, and 137 attached to the wall surface of the hot water storage tank 101 during the daytime period (7 to 23:00). When it seems that the shortage will occur, the hot water boiling operation is performed to secure the necessary amount of hot water in the upper part of the hot water storage tank 101. By the above boiling operation, the hot water storage tank 101 accumulates in layers in the order of high temperature water, medium temperature water, and low temperature water from the top.

  Further, of the remaining hot water temperature detectors 135, 136, and 137, the remaining hot water temperature detector 136 provided in the vicinity of the intermediate hot water discharge pipe 112 determines whether or not the intermediate hot water exists in the hot water storage tank 101. Therefore, when compared with a predetermined first set temperature (for example, 30 ° C.) and the temperature detected by the remaining hot water temperature detector 136 is equal to or higher than the first set temperature, in the vicinity of the medium temperature hot water discharge pipe 112 The middle temperature detecting means for determining that the medium temperature water is present in the hot water storage tank 101 is configured.

  Further, the remaining hot water temperature detector 137 determines whether or not hot water in the hot water storage tank 101 is flowing without stagnation because high temperature water in the upper part of the hot water storage tank 101 is used and new water is supplied from the water supply pipe 105. In order to judge, it compares with the predetermined 2nd preset temperature (for example, 45 degreeC), and it judged that the temperature detected with the remaining hot water temperature detector 137 was not less than the 2nd preset temperature in this comparison result. When the hot water in the hot water storage tank 101 is not used or the amount of use is extremely small, the upper temperature detecting means is configured.

  The stored hot water is supplied from the hot water remote controller 132 or the bath remote controller 133 so that the control unit 134 controls the load side mixing valve of the usage side circuit to supply desired hot water to the usage side terminal. Yes.

An example of the operation of the user side circuit in the present embodiment will be described with reference to FIGS. 3 and 4. First, when a desired hot water supply temperature is set by the hot water supply remote controller 132 and the currant 124 is opened, the water supply pipe 105 is opened. The hot water storage tank 101 is started to supply water, and the hot water and intermediate hot water in the hot water storage tank 101 are discharged from the hot water discharge pipe 111 and the intermediate hot water discharge pipe 112 by the supply water pressure, and the hot water side a and the water side b of the first mixing valve 120 are discharged. To be supplied. At this time, if the water side b is kept fully open as an initial setting of the first mixing valve 120, the medium temperature water in the hot water storage tank 101 is discharged preferentially and supplied to the next stage from the mixing outlet side c. When this hot water temperature is detected by the first temperature detector 121 and the detected hot water temperature is higher than a temperature set by the hot water supply remote controller 132 by a predetermined temperature (for example, 2 ° C.), the valve opening is further increased to the water side. Since it cannot be adjusted, the supply of the medium-temperature water is continued in this state, and the hot water at the set temperature is supplied to the currant 124 by being mixed with the water supplied from the water supply pipe 105 by the hot water supply mixing valve 122 in the next stage.

  Next, when the hot water temperature detected by the first temperature detector 121 is lower than the temperature set by the hot water supply remote controller 132, the opening of the hot water side a of the first mixing valve 120 is opened and the high temperature from the high temperature hot water discharge pipe 111 is increased. Water is introduced and mixed with warm water to start control of the valve opening so that the target temperature is reached (hot water flows through the path indicated by the thick line). By this control, the outlet temperature of the first mixing valve 120 gradually approaches the target temperature, and hot water having a preset target temperature is supplied to the hot water side d of the hot water supply mixing valve 122 in the next stage. Then, the hot water mixing valve 122 mixes with the water supplied from the water supply pipe 105 to supply hot water having a set temperature to the currant 124.

  As described above, in the normal operation, the hot water is supplied to the use side terminal such as the currant 124 by preferentially using the medium temperature water accumulated in the hot water storage tank 101 by the first mixing valve 120. The low-temperature water can be secured, the use of the high-temperature water above the hot water tank can be minimized, the boiling operation of the high COP and the suppression of the hot water phenomenon can be achieved. A very effective means can be secured as a hot water utilization form.

  However, the preferential use form of the medium-temperature water in the above configuration is that when the amount of hot-water used is extremely small or not used at all for a long time while the medium-temperature water exists in the hot-water tank 101, the hot-water tank 101 The temperature of the hot water in the inside decreases, and the temperature distribution is such that miscellaneous bacteria are likely to propagate in the lower part of the hot water storage tank 101. In particular, when Legionella bacteria propagate, there is a possibility of causing harm to the human body. That is, if the use of hot water is extremely small and the hot water flow in the hot water storage tank 101 is lost, it becomes easy for bacteria such as Legionella bacteria to propagate, and if the use is continued in such a state, the hot water where the bacteria propagated. Since hot water is preferentially taken out from the intermediate temperature hot water pipe 112 close to the lower part of the tank, the propagated miscellaneous bacteria will be discharged from the intermediate temperature hot water pipe 112 at an early stage when hot water is used, and discharged to the outside through the currant 124 or the like. . If Legionella bacteria are mixed in the discharged germs, they will be scattered in the air, which will adversely affect the human body from the respiratory system.

  Therefore, when the hot water supply apparatus in the present embodiment enters the night time zone in which the full-boiling operation is performed, first, the middle temperature detection means configured by the remaining hot water temperature detector 136 is used to obtain a substantially intermediate portion of the hot water storage tank 101. It is detected whether or not medium temperature water exists. That is, it is determined whether the temperature detected by the remaining hot water temperature detector 136 is equal to or higher than a first set temperature (for example, 30 ° C.). When it is determined that the temperature is equal to or lower than the first set temperature, a large amount of water is supplied from the water supply pipe into the hot water storage tank 101, and the amount of hot water used in the tank is large and flows without stagnation. Judge.

  Next, the upper temperature detecting means constituted by the remaining hot water temperature detector 137 detects whether or not there is a high temperature water replacement phenomenon in a substantially upper part of the hot water storage tank 101. That is, whether or not the temperature detected by the remaining hot water temperature detector 137 has become equal to or lower than a preset second set temperature (for example, 45 ° C.) before entering the night time zone in which the total amount heating operation is performed. If the temperature detected by the remaining hot water temperature detector 137 is lower than the second set temperature even once, the phenomenon of switching between the high temperature water and the low temperature water below the middle temperature water substantially in the upper part of the hot water storage tank 101. When the water temperature in the tank is judged to have flowed due to use and the temperature has never dropped below the second set temperature, the amount used is extremely small or not used at all, and the water in the tank is stagnant Judge.

  As described above, when it is determined by the middle temperature detection means and the upper temperature detection means that the medium temperature water exists in the hot water storage tank 101 and the flow of the hot water in the tank cannot be confirmed, the hot water discharge from the medium temperature hot water discharge pipe 112 is prohibited. The hot water use prohibition mode is set, the valve opening on the hot water side a of the first mixing valve 120 is driven to a fully open state, and then a control prohibition release signal is output from the control unit 134 satisfying a predetermined condition. Until then, the middle hot water use prohibition mode in which the control of the first mixing valve 120 is prohibited is continued, and the hot water side fully open state is maintained.

  With this control, the hot water usage form during the medium hot water use prohibition mode period is such that hot water supplied from the upper hot water discharge pipe 111 of the hot water storage tank 101 is supplied to the hot water supply mixing valve 122 which is a load side mixing valve via the first mixing valve 120. The hot water at the set temperature is used from the currant 124 by being supplied to the hot water d and mixed with the water on the water e supplied from the water supply pipe 105.

  Even if miscellaneous bacteria such as Legionella bacteria propagate in the lower part of the hot water storage tank 101 during the period in which the flow of hot water in the tank is extremely small or not used at all, and the flow of hot water in the tank stagnate, In hot water use during the use prohibition mode, hot water supply from the intermediate temperature hot water discharge pipe 112 is prohibited, and since hot water at a relatively high temperature in the upper part of the tank is used preferentially, it is possible to suppress the outflow of various bacteria. it can.

  Then, when the entire hot water storage tank 101 is heated in the medium hot water use prohibition mode and the total amount in the hot water storage tank 101 reaches a temperature at which miscellaneous bacteria such as Legionella bacteria are killed, for example, 65 ° C. or higher, the control unit 134 A control prohibition release signal for the mixing valve 120 is output, and the mixing control by normal temperature hot water preferential removal from the medium temperature hot water discharge pipe 112 is resumed.

  As a specific embodiment thereof, when the middle temperature detection means and the upper temperature detection means determine that the medium warm water use prohibition mode is set, the hot water runs out after the full-boiling operation performed in the first night time period has elapsed. After the daytime period when the boiling operation is performed, the control prohibition of the first mixing valve 120 is canceled, and the medium warm water use prohibition mode is changed to the normal mode. In order to prohibit the control of the 1 mixing valve 120 and prohibit the supply of hot water from the intermediate temperature hot water discharge pipe 112, it is possible to prevent the outflow of miscellaneous bacteria such as Legionella that have propagated in the lower part of the hot water storage tank 101 during the intermediate temperature water use prohibition mode. It is possible to boil the entire tank containing hot water at the bottom of the hot water storage tank 101 to a hot water temperature of 65 ° C. or higher at which Legionella dies. By performing the hot and cold water mixing control using the control of the first mixing valve 120 after a lapse of time zone operation, it is possible to ensure effective hot water utilization form in the absence of bacteria, such as Legionella.

  Note that the values of the first set temperature and the second set temperature set to determine the presence / absence of the medium temperature water and the use status are not limited to the present embodiment, and are arbitrarily set according to the tank capacity and the like. Is possible.

A specific control operation in the above embodiment will be described with reference to the flowchart of FIG. 5. First, in FIG. 5, a normal operation is performed by preferential use of the intermediate temperature water from the intermediate temperature hot water pipe 112 in Step 1. In step 2, it is determined whether or not the night time zone has been entered. If it is determined that the night time zone has been entered, the remaining hot water temperature detector 136 detects in step 3 the first hot water temperature detected in advance. It is determined whether or not the temperature is equal to or higher than the set temperature. If the temperature is equal to or higher than the first set temperature, it is determined that medium temperature water exists in the hot water storage tank 101. When the temperature is equal to or lower than the first set temperature, it is determined that water is supplied from the water supply pipe 105 and there is a flow of hot water in the tank, and the process proceeds to step 6 to start a full-boiling operation. When it is determined in step 3 that medium-temperature water exists, the second set temperature set in advance until the hot water temperature detected by the remaining hot water temperature detector 137 in step 4 enters the night time zone during which the entire boiling water operation is performed. It is determined whether or not it has fallen below, and when it is determined that it has fallen even once, it is determined that there is a flow of hot water in the tank, and the routine proceeds to step 6 to start a full-boiling operation. When it is determined in step 4 that the temperature has never been lowered, the middle hot water use prohibition mode is set, the valve opening of the first mixing valve 120 is driven so that the hot water side a is fully opened, and then the first mixing valve The control of the valve opening of 120 is prohibited. Next, it is determined in step 6 whether or not the entire boiling water heating operation of the hot water storage tank 101 has been completed, and when it is determined that it has been completed, that is, the hot water temperature in the hot water storage tank 101 is equal to or higher than a predetermined temperature at which germs and the like die When this happens, the control prohibition state of the first mixing valve 120 is canceled in step 7 to return to the normal operation.

  In addition, as a judgment of the completion of all-boiling operation in step 6, it is judged whether or not it is the daytime time zone, and the control prohibition state of the first mixing valve 120 is released after the daytime time zone is reached. Thus, the circuit configuration can be simplified.

  As described above, the hot water storage type hot water supply apparatus of the present invention provides a hot water mixing control method capable of preferentially using medium hot water, which is an extremely effective means for using hot water in a heat pump type hot water supply apparatus, while the amount of hot water used is extremely high. Therefore, it is possible to ensure the safety when the use of hot water is stagnant, and can be applied to general hot water mixing control regardless of the heat source.

The block diagram of the hot water storage type hot water supply apparatus in Embodiment 1 of this invention The figure which shows the boiling operation in the hot water storage type hot water supply apparatus The figure which shows an example of the hot water usage form in the hot water storage type hot water supply apparatus The figure which shows another example of the hot water usage form in the hot water storage type hot water supply apparatus Flow chart showing control operation in the hot water storage type hot water supply apparatus

DESCRIPTION OF SYMBOLS 101 Hot water storage tank 105 Water supply pipe 106 Heat pump circuit 111 Hot water discharge pipe 112 Medium temperature hot water supply pipe 120 1st mixing valve 122 Hot water supply mixing valve (load side mixing valve)
125 Bath mixing valve (load-side mixing valve)
134 Control unit 135 Remaining hot water temperature detector (central temperature detection means)
137 Residual hot water temperature detector (upper temperature detection means)
140 Timer part

Claims (3)

In a hot water storage hot water supply apparatus that stores hot water heated using a heat pump circuit in a stratified state from the upper part of the tank and supplies the desired hot water to the terminal side using the hot water,
A tapping pipe for taking out the hot water at the upper part of the tank, an intermediate temperature tapping pipe for taking out hot water at the substantially middle part of the tank, a middle temperature detecting means for detecting the hot water in the tank near the middle temperature tapping pipe, the middle temperature tapping pipe and the upper tapping pipe An upper temperature detecting means for detecting the hot water temperature in the tank, a first mixing valve for mixing hot water from the outlet hot water pipe and the intermediate temperature hot water pipe, hot water from the first mixing valve and water from the water supply pipe A use side mixing valve that mixes and supplies hot water at a predetermined temperature to the terminal side, and a control unit that performs valve opening control of the first mixing valve and the use side mixing valve,
A hot water storage type hot water supply apparatus that sets a time zone for performing a full-boiling operation and sets a hot-water boiling operation when it is determined that the amount of hot water is insufficient,
The control unit is configured such that, during the time period for performing the total boiling operation, the hot water temperature detected by the middle temperature detecting means is 30 ° C. or higher, and the hot water temperature detected by the upper temperature detecting means is 45 ° C. or higher. When the operation is continued for a predetermined time, the first mixing valve is driven so as to be fully opened toward the outlet pipe side. The hot water storage type hot water supply apparatus according to claim 1, wherein the controller is configured to return the hot water / water mixing control of the first mixing valve when it is confirmed that the full boiling operation has been completed under a predetermined boiling condition. The control unit returns the hot water / water mixing control of the first mixing valve after the time zone for performing the hot water boiling operation after the time of the first full-boiling operation has elapsed. The hot water storage type hot water supply apparatus described.