JP4256857B2 - Hot water storage hot water supply system - Google Patents

Description

  The present invention relates to a hot water storage hot water supply system that stores hot water heated by power generation heat, solar heat, or the like in a hot water storage tank and supplies hot water as needed using the hot water stored in the hot water storage tank. In particular, the present invention relates to a technique for preventing hot water stored for a long time from being used as it is when hot water in a hot water tank is not used for a long period of time in a hot water storage hot water supply system.

2. Description of the Related Art A hot water supply system is known that stores hot water heated by power generation heat, solar heat, or the like to supply hot water. Hot water heated by generated heat or solar heat is stored in a hot water tank. The hot water stored in the hot water storage tank is mixed with tap water in a mixing unit or heated with a heater as needed to adjust the temperature to an appropriate temperature.
In a hot water supply system that uses hot water stored in a hot water storage tank, if the hot water supply system is not used for a long period of time, the hot water in the hot water tank will not be replaced during that time, and the hot water in the hot water tank will gradually decrease in temperature due to heat dissipation. To do. If hot water is stored, it will be sterilized. However, if hot water with reduced temperature is stored, there is no possibility that harmful bacteria such as Legionella bacteria will propagate in the hot water tank.

  In order to deal with the above problem, for example, in the hot water storage type hot water supply apparatus of Patent Document 1, the hot water in the hot water tank is heated to raise the temperature, and the sterilization operation is maintained at a sterilizable temperature that can sterilize the bacteria for a certain period of time. Is executed. This sterilization operation is executed when a state in which the hot water temperature in the hot water tank is lower than the sterilizable temperature continues for a predetermined time or more, or is executed at regular time intervals. In the hot water storage type hot water supply apparatus of Patent Document 1, since it is not necessary to execute and manage the sterilization operation by the user, the convenience is improved and the sterilization operation is performed at an appropriate time without excess or deficiency, which contributes to energy saving. It is said.

JP 2004-150649 A

There is a possibility that bacteria such as Legionella bacteria will propagate in the hot water tank when the hot water in the hot water tank is not used for a long time. Most of the time when the hot water in the hot water tank is not used for a long time is when the user is absent for a long time.
In the hot water storage type hot water supply apparatus of Patent Document 1, if the state in which the hot water temperature in the hot water storage tank is lower than the sterilizable temperature continues for a predetermined time or longer, the sterilization operation is executed even if the user is absent. If the user is not present after the sterilization operation is performed, the sterilization operation is performed again. That is, in the hot water storage type hot water supply apparatus of Patent Document 1, the sterilization operation is performed at an appropriate time without excess or deficiency. However, if the user is absent for a long time, the inside of the hot water storage tank is in the absence of the user. It can happen that hot water is sterilized several times on a regular basis. However, it is sufficient that the sterilization treatment of the hot water in the hot water tank is performed once just before using the hot water. If the sterilization process is performed many times before using the hot water in the hot water storage tank as in the hot water storage type hot water supply device of Patent Document 1, the convenience is improved, but from the viewpoint of energy saving, it is rather a waste of energy. I must say that it is an errand.
The present invention provides a technique capable of treating hot water in a hot water storage tank that has not been used for a long period of time at an appropriate timing and without wasting energy and resources, so that the hot water supply system can be used in a sanitary manner. With the goal.

The hot water storage type hot water supply system of the present invention is a hot water storage tank for storing hot water, a heating means for heating the hot water stored in the hot water storage tank, and the mixing ratio of the hot water and tap water from the hot water storage tank can be adjusted. A mixing unit, a hot water path connecting the hot water storage tank and the mixing unit, and an open / close valve for opening and closing the hot water path are provided. Further, the hot water storage type hot water supply system includes a temperature detecting means for detecting a hot water temperature in the hot water tank, a use state determining means for determining whether or not the hot water in the hot water tank is being used, and a use state. A first time measuring means for measuring an elapsed time from when the determining means determines that the hot water in the hot water tank is not being used; a home determining means for determining whether the user is at home; There is also provided second time measuring means for measuring the time during which the hot water temperature detected by the temperature detecting means is equal to or higher than a predetermined temperature set to be equal to or higher than the sterilizable temperature . Further, this hot water storage type hot-water supply system is used by the home determination means while the on-off valve is prohibited from being opened when the time counted by the first time-counting means exceeds the first predetermined time, and the on-off valve is prohibited from being opened. person when it is determined that it is a home, perform the heat sterilization treatment to maintain the temperature of hot water that time measured by the second timer means is the temperature detecting means until the Do and the second predetermined time is detected more than the predetermined temperature Then, on / off valve control means for releasing the open / close prohibition state of the on / off valve is also provided.

If the hot water in the hot water tank is not used for a long time, harmful bacteria such as Legionella bacteria may propagate in the hot water in the hot water tank. It is necessary to avoid the use of hot water in which bacteria are propagated as it is. Bacteria such as Legionella are vulnerable to heat and are known to die in a relatively short time (about 5 minutes) when heated to 60 ° C. or higher. Heat sterilization is effective for sterilizing hot water in a hot water tank.
When the hot water in the hot water tank is not used for a long period of time, if the hot water in the hot water tank is sterilized according to the elapsed time or the hot water temperature, the heat sterilization is performed in the absence of the user. Can happen. Even if heat sterilization is performed in the absence, high-temperature hot water after heat sterilization is not used immediately, and eventually the heat is released and the temperature drops. If a user's absence period becomes long, the hot water in a hot water storage tank will be heat-sterilized many times. The act of repeatedly heating and dissipating heat from hot water whose scheduled use time is undecided is nothing but a waste of energy.

In the hot water storage hot water supply system of the present invention, in order to heat the hot water stored in the hot water storage tank, one that uses generated heat generated when power is generated by the power generation device, one that uses solar heat, and the like can be exemplified. .
In the hot water storage type hot water supply system of the present invention, it is determined whether the hot water in the hot water tank is not used, and the time during which the hot water in the hot water tank is not used is counted. If the measured time exceeds a predetermined time (for example, 48 hours), it is possible that bacteria have propagated in the hot water in the hot water tank, and the use of the hot water in the hot water tank is prohibited by opening the on-off valve. . Opening of the on-off valve is prohibited until the heat sterilization of the hot water in the hot water tank is completed. Heat sterilization of hot water in the hot water tank is performed when it is determined that the user is at home. When the user is absent, heat sterilization is not performed. For heating the hot water in the hot water storage tank, the above-described heating means (one that uses generated heat, solar heat, or the like) already used in the hot water supply system is used. Or you may heat using an existing heater. When the hot water temperature in the hot water tank is equal to or higher than a predetermined temperature (for example, 60 ° C.) and the second predetermined time (for example, 1 hour) elapses, it is determined that the heat sterilization has been completed. Use of warm water is allowed.
According to the hot water storage type hot water supply system of the present invention, the heat sterilization treatment of the hot water in the hot water storage tank is not performed until the user's home is detected, but is performed only once when the user returns home. The hot water in the hot water storage tank is heat sterilized immediately before use, and the hot water heated by heat sterilization can be used effectively. Since the heat sterilization of the hot water in the hot water tank can be completed only once, the energy efficiency is good, and this one heat sterilization can be performed immediately before using the hot water, which is hygienic.
In the hot water storage type hot water supply system of the present invention, heat sterilization is started after confirming that the user is at home. Therefore, even if there is a hot water supply request immediately after the user returns home, the hot water in the hot water storage tank cannot be used for hot water supply. At this time, hot water is supplied by heating the tap water with a hot water heater existing in the hot water supply system. Although heat energy is consumed for heating tap water, the hot water in the hot water tank is heated in the absence of the user, and as a result, there is a possibility of dissipating heat without using the hot water. Compared to the system, the energy efficiency is much improved.

Another hot water storage type hot water supply system of the present invention includes a hot water storage tank that stores hot water, a mixing unit that mixes hot water and tap water from the hot water storage tank, and an adjustable mixing ratio, and hot water that connects the hot water storage tank and the mixing unit. A path and an on-off valve for opening and closing the hot water path are provided. In addition, this hot water storage type hot water supply system has a use state determining means for determining whether or not the hot water in the hot water tank is being used, and the use state determining means is a state in which the hot water in the hot water tank is not being used A first time counting means for measuring the elapsed time from the time when it is determined to be, a home determination means for determining whether or not the user is at home, a replacement means for replacing the hot water in the hot water tank, A flow rate detecting means for detecting the flow rate of the water replaced by the changing means is also provided. Further, this hot water storage type hot-water supply system is used by the home determination means while the on-off valve is prohibited from being opened when the time counted by the first time-counting means exceeds the first predetermined time, and the on-off valve is prohibited from being opened. When user determines that it is a home, Swapping flow rate detected by the flow rate detecting means executes the incoming exchange water exchange process process hot water of the hot water storage tank by Swapping means to the ing and predetermined flow rate, then, closing There is also provided on-off valve control means for releasing the valve open prohibition state.

In order to use the hot water storage hot water supply system in a sanitary manner, it is also an effective means to replace the hot water when the hot water in the hot water storage tank has not been used for a long period of time.
If the hot water in the hot water tank is not used for a long period of time, the hot water in the hot water tank can be replaced while the user is absent if the hot water in the hot water tank is replaced according to the elapsed time. It can happen to be done. Even if the replacement is performed in the absence, the water filled in the hot water tank is not used immediately, and the replacement may be necessary again. If a user's absence period becomes long, the hot water in a hot water tank will be replaced many times. The act of repeating the replacement of hot water whose scheduled use time is undecided many times is nothing but a waste of resources.

In the hot water storage type hot water supply system of the present invention, it is determined whether the hot water in the hot water tank is not used, and the time during which the hot water in the hot water tank is not used is counted. If the measured time exceeds a predetermined time (for example, 48 hours), it is possible that bacteria have propagated in the hot water in the hot water tank, and the use of the hot water in the hot water tank is prohibited by opening the on-off valve. . The opening / closing of the on-off valve is prohibited until the hot water in the hot water tank is replaced. The hot water in the hot water tank is replaced when it is determined that the user is at home. When the user is absent, the hot water in the hot water tank is not replaced. When the flow rate of the replaced water reaches a predetermined flow rate (for example, hot water tank capacity + α), it is assumed that the replacement is completed, and the open valve prohibition state is canceled and the hot water in the hot water tank (water immediately after the replacement) Use is allowed.
According to the hot water storage type hot water supply system of the present invention, replacement of hot water in the hot water storage tank is not performed until the user's home is detected, and is performed only once when the user returns home. Since the hot water in the hot water tank can be replaced once, the consumption of resources can be minimized, and this single replacement can be performed immediately before use.

In the hot water storage type hot water supply system of the present invention, it is preferable that the at-home determination unit includes a unit for detecting a predetermined change in the driving state, and determines that the user is at home when the predetermined change is detected.
Examples of the predetermined change in the operating state include a change in the detection value of the flow sensor, a change in the detection value of the power sensor, detection of device operation by a person, detection by a human body sensitive sensor, and the like. If the detection value of the flow sensor changes, it can be seen that the hot water tap is opened and water (hot water) is used, and that the user is at home. If the detection value of the power sensor changes by a predetermined value or more, it can be seen that the electric device has been used and the user is at home. If it is detected that a device operated by a person has been operated, it is known that the user is at home. If a human body is detected by the human body sensitive sensor, it is understood that the user is at home. When a plurality of these events are observed and there is some change in at least one of these events, there may be a predetermined change.

  According to the hot water storage hot water supply system of the present invention, hot water in a hot water storage tank that has not been used for a long time is subjected to heat sterilization or replacement at an appropriate timing and without wasting energy and resources. Can be used hygienically.

Hereinafter, preferred embodiments of the present invention will be described.
(Mode 1) Whether the hot water in the hot water tank is in use is determined by the open / close state of the open / close valve.
(Mode 2) Whether the user has returned home is determined by whether or not the hot-water tap has been opened.
(Mode 3) The hot water drainage path for draining the hot water in the hot water tank is branched from the hot water path connecting the hot water tank and the mixing unit, and the hot water drainage path is provided with a hot water drain path opening / closing valve. It has been.
(Mode 4) When the hot water in the hot water tank is exchanged, the exchange flow rate at which the prohibition of opening the on-off valve is released is a flow rate equal to or higher than the hot water tank capacity.
(Mode 5) When the hot water in the hot water tank has not been used for a long period of time, heat treatment is performed if the unused time is less than a third predetermined time (for example, 120 hours), and if it is not less than the third predetermined time Perform replacement processing.
(Mode 6) A mixed water heating means for heating the mixed water from the mixing unit as needed is provided, and mixing is performed when there is a hot water supply request while the opening / closing valve is prohibited from being opened by the opening / closing valve control means. The tap water from the unit is heated by the mixed water heating means to supply hot water.

Example 1
A first embodiment of the hot water storage type hot water supply system of the present invention will be described with reference to the drawings. A present Example is a cogeneration system incorporating the hot water storage type hot-water supply system of this invention.
As shown in FIG. 1, the cogeneration system of the present embodiment includes a power generation unit 110, a hot water supply system 10, and the like.
The power generation unit 110 includes a reformer 112, a fuel cell 114, heat exchangers 116 and 118, a heat medium radiator 120, a heat medium three-way valve 122, a path connecting them, and the like.
The reformer 112 is provided with a burner 131. When the burner 131 is operated to generate heat, the reformer 112 generates hydrogen gas from hydrocarbon-based gas. The high-temperature combustion gas burned by the burner 131 is guided to the combustion gas path 126. The combustion gas path 126 passes through the heat exchanger 116 from the reformer 112 and is opened to the outside. A circulation path 128 also passes through the heat exchanger 116. The combustion gas path 126 guides the high-temperature combustion gas generated in the burner 131 to the heat exchanger 116, heats the water flowing through the circulation path 128, and discharges the combustion gas whose temperature has been lowered by heat exchange to the outside.
The circulation path 128 includes a circulation return path 128 a and a circulation outward path 128 b and is connected to the hot water supply system 10. How the circulation path 128 is connected to the hot water supply system 10 will be described in detail later. The circulation path 128 circulates hot water. The hot water flowing through the circulation path 128 is heated by the combustion gas flowing through the combustion gas path 126 by passing through the heat exchanger 116, and the temperature rises.

The fuel cell 114 has a plurality of cells. The fuel cell 114 and the reformer 112 are connected by a hydrogen gas supply path 121. The hydrogen gas generated by the reformer 112 flows through the hydrogen gas supply path 121 and is supplied to the fuel cell 114. The fuel cell 114 generates power by reacting the hydrogen gas supplied from the reformer 112 with oxygen in the air. When the fuel cell 114 generates power, it generates heat.
The heat medium circulation path 124 forms a circulation path that returns to the fuel cell 114 through the fuel cell 114, the heat exchanger 118, the reserve tank 125, the heat medium pump 127, and the heat medium three-way valve 122. A heat medium temperature sensor 117 and a freezing prevention heater 123 are mounted on the downstream side of the fuel cell 114 in the heat medium circulation path 124. The heat medium temperature sensor 117 detects the temperature of the heat medium flowing through the heat medium circulation path 124. The detection signal of the heat medium temperature sensor 117 is output to the controller 21 attached to the hot water supply system 10. The antifreezing heater 123 is an electric heater that heats the heat medium circulation path 124.
The heat medium three-way valve 122 includes one inlet 122a and two outlets 122b and 122c. The heat medium three-way valve 122 switches between communication between the inlet 122a and the outlet 122b or communication between the inlet 122a and the outlet 122c.
A cooling path 129 that connects the outlet 122b of the heat medium three-way valve 122 and the downstream side of the outlet 122c of the heat medium three-way valve 122 of the heat medium circulation path 124 is provided. The heat medium circulation path 124 and the cooling path 129 circulate pure water as a heat medium. A heat medium radiator 120 is mounted in the middle of the cooling path 129. A heat medium cooling fan 119 is provided adjacent to the heat medium radiator 120. When the heat medium cooling fan 119 is operated, air is blown to the heat medium radiator 120, and the heat medium flowing through the cooling path 129 is cooled.
The controller 21 controls the reformer 112, the fuel cell 114, the burner 131, the heat medium pump 127, the antifreezing heater 123, the heat medium three-way valve 122, and the heat medium cooling fan 119.

When the fuel cell 114 is activated, the inlet 122a and the outlet 122c of the heat medium three-way valve 122 are communicated and the heat medium pump 127 is operated. When the heat medium pump 127 is operated, the heat medium circulates through the heat medium circulation path 124. The heat generation medium is recovered from the fuel cell 114 by circulating the heat medium through the heat medium circulation path 124. The generated heat recovered by the heat medium is transported together with the heat medium to the heat exchanger 118 and heats the hot water flowing through the circulation path 128. The circulation path 128 will be described later.
If the temperature of the heat medium detected by the heat medium temperature sensor 117 becomes too high, the generated heat is not sufficiently recovered, and thus the generated heat is dissipated. The inlet 122a and outlet 122b of the heat medium three-way valve 122 are communicated with each other, and the heat medium cooling fan 119 is operated at the same time. When the inlet 122 a and the outlet 122 b of the heat medium three-way valve 122 communicate with each other, the heat medium flows into the cooling path 129 and passes through the heat medium radiator 120. The heat medium is cooled by passing through the heat medium radiator 120. The heat medium radiator 120 radiates heat with high efficiency when air is blown from the heat medium cooling fan 119. When the temperature of the heat medium decreases, the inlet 122a and the outlet 122c of the heat medium three-way valve 122 are communicated again. By repeating such switching of the heat medium three-way valve 122, the temperature of the heat medium is maintained within a predetermined range.

The hot water supply system 10 includes a hot water tank 20, a hot water heater (heater) 22, a mixing unit (mixer) 24, a plurality of paths that connect these, a controller 21, and the like.
A water supply path 26 for supplying tap water to the hot water tank 20 is connected to the bottom of the hot water tank 20. In the vicinity of the inlet 26 a of the water supply path 26, a pressure reducing valve 28 is attached. The downstream side of the pressure reducing valve 28 in the water supply path 26 and the water supply inlet 24 a of the mixing unit 24 are connected by a mixing unit water supply path 30. The pressure reducing valve 28 adjusts the water supply pressure to the hot water tank 20 and the mixing unit 24. When the hot water in the hot water storage tank 20 decreases or the water supply inlet 24a of the mixing unit 24 opens, the downstream pressure of the pressure reducing valve 28 decreases. The pressure reducing valve 28 opens when the downstream pressure decreases, and tries to maintain the pressure at a predetermined pressure regulation value. For this reason, when the hot water in the hot water storage tank 20 decreases or the water supply inlet 24a of the mixing unit 24 opens, tap water is supplied to them.
The hot water storage tank 20 stores water regulated to a regulated pressure value. The hot water tank 20 is formed of a pressure resistant container that can withstand the pressure regulation value. An outlet 20a is provided at the upper part of the hot water tank 20, and a relief valve 31 is mounted thereon. The valve opening pressure of the relief valve 31 is set slightly higher than the pressure regulation value of the pressure reducing valve 28. When the pressure regulation of the pressure reducing valve 28 becomes impossible, the relief valve 31 is opened to prevent the pressure in the hot water tank 20 from exceeding the pressure resistance. One end 32 a of a pressure release path 32 is connected to the relief valve 31. The other end 32 b of the pressure release path 32 is open to the outside of the hot water tank 20.
A drainage path 33 that connects the bottom of the hot water tank 20 and the vicinity of the other end 32 b of the pressure release path 32 is provided. A drain valve 34 is attached in the middle of the drain path 33. The drain valve 34 can be manually opened and closed. When the drain valve 34 is opened, the water in the hot water tank 20 is drained to the outside through the drain path 33 and the open path 32.

The hot water tank 20 is connected to the circulation path 128 (circulation return path 128a, circulation forward path 128b) of the power generation unit 110. Specifically, the circulation return path 128 a is connected to the upper part of the hot water tank 20, and the circulation forward path 128 b is connected to the lower part of the hot water tank 20. Thereby, a circulation path between the hot water tank 20 and the power generation unit 110 is formed. A circulation pump 40 is mounted in the middle of the circulation outward path 128b. A return thermistor 45 is attached to the circulation return path 128a, and an outward thermistor 44 is attached to the circulation outward path 128b. The return thermistor 45 detects the temperature of hot water in the circulation return path 128a, and the outward thermistor 44 detects the temperature of hot water in the circulation return path 128b. Detection signals from the return thermistor 45 and the outward thermistor 44 are output to the controller 21.
When the circulation pump 40 is activated during the power generation operation, hot water is sucked from the bottom of the hot water tank 20. The hot water sucked from the hot water storage tank 20 is heated by passing through the heat exchangers 118 and 116 of the power generation unit 110 after flowing through the circulation outward path 128b, and the temperature rises. The hot water whose temperature has risen flows through the circulation return path 128 a and is returned to the upper part of the hot water tank 20. In this way, the hot water sucked out from the bottom of the hot water tank 20 is heated by the heat exchangers 118 and 116 of the power generation unit 110 to become higher temperature, and the circulation returning to the upper part of the hot water tank 20 is performed. Hot water is stored in the hot water tank 20. When the hot water from the power generation unit 110 is returned to the hot water tank 20 from the state where the temperature in the hot water tank 20 is low, the hot water is returned to the upper part of the hot water tank 20, so that the high temperature layer is formed above the cold water layer. Is formed (hereinafter referred to as “temperature stratification”). The temperature of water deeper than the high temperature layer drops rapidly. During power generation, when the low temperature hot water is sucked out from the bottom of the hot water tank 20 and the high temperature hot water continues to be returned to the top, the high temperature layer does not cross with the low temperature layer, and the thickness (depth) of the low temperature layer gradually increases. It becomes smaller and the thickness (depth) of the high temperature layer becomes gradually larger. In a state where the hot water storage tank 20 is fully stored, high temperature hot water is stored in the entire hot water storage tank 20. By forming the temperature stratification, high-temperature hot water is sent out from the outlet 20a provided at the uppermost part of the hot water tank 20, even if the hot water tank 20 is not fully heat-accumulated. On the other hand, when hot water in the hot water tank 20 is used, hot hot water at the top of the hot water tank 20 is sucked out, and when tap water enters from the bottom, the thickness (depth) of the high temperature layer gradually decreases, and the low temperature layer The thickness (depth) of the film gradually increases. When the hot water in the hot water tank 20 is used up, the hot water tank 20 is filled with tap water.

  The controller 21 includes a CPU, a ROM, a RAM, and the like, and the power generation unit 110 and the hot water supply system 10 are controlled by the CPU processing a control program stored in the ROM. The RAM temporarily stores various signals input to the controller 21 and various data generated in the course of execution of processing by the CPU. A remote controller 23 is connected to the controller 21. The remote controller 23 is provided with switches and buttons for operating the power generation unit 110 and the hot water supply system 10, a liquid crystal display for displaying the operation state of the power generation unit 110 and the hot water supply system 10 and displaying an operation method described later. Yes.

  An upper thermistor 35 is attached at a location 5 liters from the top of the hot water tank 20, and a lower thermistor 36 is attached at a location 5 liters from the bottom. The upper thermistor 35 detects the hot water temperature in the upper part of the hot water tank 20. The lower thermistor 36 detects the hot water temperature in the lower part of the hot water tank 20. The detection signals of the upper thermistor 35 and the lower thermistor 36 are output to the controller 21, respectively. The detected temperatures of the upper thermistor 35 and the lower thermistor 36 are used not only for hot water temperature control but also for calculating the heat storage amount. The calculated heat storage amount is stored over time in a storage unit prepared in the controller 21.

  The mixing unit 24 includes a hot water inlet 24c, a mixed water outlet 24b, a first flow rate sensor 67, a hot water thermistor 50, a water supply thermistor 48, a mixed water thermistor 54, a high-cut thermistor 55, and the water supply inlet 24a already described. The outlet 20 a of the hot water tank 20 and the hot water inlet 24 c of the mixing unit 24 are connected by a hot water path 42. The warm water path 42 is provided with a warm water flow rate sensor 46 and a warm water path opening / closing valve 43. A hot water drainage path 41 is branched from the middle of the hot water path 42. The hot water drainage path 41 is provided with a hot water drainage path opening / closing valve 49. When the hot water drainage path opening / closing valve 49 is opened, tap water is sent from the water supply path 26 to the hot water storage tank 20 and is pushed out therefrom, so that the hot water from the hot water storage tank 20 is drained outside the hot water supply system 10. While the hot water drainage path opening / closing valve 49 is opened, the hot water path opening / closing valve 43 is closed. The hot water flow rate sensor 46 detects the flow rate of hot water delivered from the hot water storage tank 20. The first flow sensor 67 detects the flow rate of the mixed water flowing out from the mixed water outlet 24b. The hot water thermistor 50 detects the temperature of the hot water flowing into the hot water inlet 24c. The water supply thermistor 48 detects the temperature of the tap water flowing into the water supply inlet 24a. The mixed water thermistor 54 and the high cut thermistor 55 detect the temperature of the mixed water flowing out from the mixed water outlet 24b. Detection signals of the hot water flow sensor 46, the hot water path on / off valve 43, the hot water drain path on / off valve 49, the first flow sensor 67, the hot water thermistor 50, the feed water thermistor 48, the mixed water thermistor 54, and the high cut thermistor 55 are output to the controller 21. .

The controller 21 uses the detection signal of the mixed water thermistor 54 to change the opening on the hot water inlet 24c side and the opening on the water supply inlet 24a side. While the hot water inlet 24c is open, the hot water path opening / closing valve 43 is also opened. While the hot water inlet 24c is closed, the hot water path opening / closing valve 43 is also closed. When the opening degree on the hot water inlet 24c side and the opening degree on the water supply inlet 24a side are changed, the mixing ratio between the hot water from the hot water storage tank 20 and tap water (cold water) is adjusted. When the mixing ratio between the hot water from the hot water tank 20 and the tap water is adjusted, the temperature of the hot water flowing out from the mixed water outlet 24b is maintained at a predetermined value. By using the controller 21 and the mixing unit 24 in combination, the temperature of the mixed water measured by the mixed water thermistor 54 is adjusted to the temperature commanded by the controller 21.
When it is detected by the high-cut thermistor 55 that the hot water has greatly exceeded the predetermined value (that is, when there is a high possibility that the mixed water thermistor 54 or the mixing unit 24 has failed), the controller 21 opens the hot water inlet 24c. close. When the hot water inlet 24c is closed, the hot water having a temperature that greatly exceeds the predetermined value is prevented from being supplied to the water heater 22.
A mixed water outlet 24 b of the mixing unit 24 and a burner heat exchanger 52 (described later) of the water heater 22 are connected by a mixed water path 51. A second flow rate sensor 47 is attached to the mixed water path 51. A detection signal from the second flow sensor 47 is output to the controller 21.

The water heater 22 includes burner heat exchangers 52 and 60, burners 56 and 57, a reheating heat exchanger 58, a replenishing water valve 59, a cistern 61, and the like. Hot water flows from the mixing unit 24 into the burner heat exchanger 52 via the mixed water path 51. The gas combustion type burner 56 heats the burner heat exchanger 52. When the burner 56 receives an ignition instruction from the controller 21, it starts combustion after performing a pre-purge operation. The time required for the pre-purge is set based on the size and rotational speed of the combustion fan, the capacity of the portion where the combustion gas of the burners 56 and 57 passes through the burner heat exchangers 52 and 60, and is exhausted to the outside of the apparatus. 21 is stored. The pre-purge usually takes several seconds. In the burner 56 of this embodiment, the time for the pre-purge is 1.5 seconds.
The downstream side of the burner heat exchanger 52 and the hot water tap 64 are connected by a hot water tap path 63. The hot-water tap 64 is arranged in a bathroom, a washroom, a kitchen, etc. (in FIG. 1, the plurality of hot-water taps 64 are represented by one). A hot water supply thermistor 65 is attached to the hot water supply passage 63. The hot water supply thermistor 65 detects the temperature of hot water flowing out of the burner heat exchanger 52. A detection signal from the hot water supply thermistor 65 is output to the controller 21.

  A bypass pipe 37 that bypasses the burner heat exchanger 52 is formed in the mixed water path 51. The bypass pipe 37 is provided with a bypass servo 38. The opening degree of the bypass servo 38 is controlled by the controller 21, and the opening degree is adjusted by driving a built-in stepping motor. When the bypass servo 38 is opened, there is a bypass path that branches from the upstream side of the burner heat exchanger 52 in the mixed water path 51, passes through the bypass pipe 37, and joins the downstream side of the burner heat exchanger 52 in the mixed water path 51. It is formed. By controlling the opening degree of the bypass servo 38 by the controller 21, the bypass ratio that is the ratio of the flow rate to the bypass pipe 37 with respect to the flow rate to the burner heat exchanger 52 is controlled.

From the middle of the mixed water path 51 in the water heater 22, a systern water inlet path 62 is branched. The open end of the cistern water intake path 62 is inserted into the upper part of the cistern 61. A makeup water valve 59 is provided in the middle of the cistern water intake path 62. The makeup water valve 59 is controlled by the controller 21 and opens and closes when a built-in solenoid is driven. When the replenishing water valve 59 is opened, hot water from the mixing unit 24 is supplied to the cistern 61.
A water level electrode 66 is mounted in the cis turn 61. The water level electrode 66 has a rod-shaped high level switch 66a and a low level switch 66b. The lower end of the high level switch 66 a is located at the high level water level of the cistern 61. The lower end of the low level switch 66 b is located at the low level water level of the cistern 61. The high level switch 66a and the low level switch 66b output a detection signal to the controller 21 when they are in contact with water. Based on the detection signal from the water level electrode 66, the controller 21 determines whether the water level of the cistern 61 exceeds the high level water level, is between the high level water level and the low level water level, or is lower than the low level water level. What is appropriate as the cis turn 61 is a state where the water level is located between the high level and the low level. The controller 21 controls opening / closing of the replenishing water valve 59 based on the water level detection signal from the water level electrode 66 and maintains the water level of the cistern 61 within an appropriate range.

One end of a cistern water discharge path 68 is connected to the bottom of the cistern 61. A heating pump 69 is mounted in the middle of the cistern water discharge path 68. The heating pump 69 is controlled by the controller 21. The other end of the cistern water discharge path 68 branches into a burner upstream path 71 and a low-temperature water path 70. The burner upstream path 71 connects the cistern water discharge path 68 and the upstream side of the burner heat exchanger 60. A heating low temperature thermistor 72 that detects the temperature of the hot water flowing inside is installed in the burner upstream path 71. A detection signal of the heating low temperature thermistor 72 is output to the controller 21.
The gas combustion type burner 57 heats the burner heat exchanger 60. The downstream of the burner heat exchanger 60 and the cistern 61 are connected by a high-temperature water path 73. A heating high temperature thermistor 74, a heating terminal thermal valve 75, and a heating terminal 76 are attached to the high temperature water path 73 in order from the upstream side.
The heating high temperature thermistor 74 detects the temperature of the hot water flowing through the high temperature water path 73. A detection signal of the heating high temperature thermistor 74 is output to the controller 21.

The heating terminal 76 includes a heat exchanger 76b, an operation switch 76a, and an electric fan (not shown). The heat exchanger 76 b performs heat exchange between the hot water flowing through the high temperature water path 73 and the air. The operation switch 76 a is connected to the heating terminal thermal valve 75 and the controller 21.
The heating terminal thermal valve 75 includes an expansion element and an on-off valve mechanically connected to the expansion element. When the operation switch 76a of the heating terminal 76 is turned on, power is supplied to the expansion element of the heating terminal thermal valve 75. The energized expansion element becomes hot and expands. The expanded expansion element drives the on-off valve, thereby opening the heating terminal thermal valve 75. Further, when the operation switch 76 a is turned on, the controller 21 operates the heating pump 69. As described above, when the operation switch 76a is turned on, the heating terminal thermal valve 75 is opened, and when the heating pump 69 is activated, hot water is sucked from the cistern 61. The controller 21 controls the burner 57 based on the hot water temperature detected by the heating low temperature thermistor 72 and the heating high temperature thermistor 74, and maintains the temperature of the hot water flowing out of the burner heat exchanger 60 within a predetermined range. The electric fan of the heating terminal 76 rotates when the operation switch 76a is turned on, and blows air to the heat exchanger 76b. The air blown to the heat exchanger 76b is warmed by exchanging heat with warm water via the heat exchanger 76b. Warmed air blows out from the heating terminal 76 to heat the room. By performing heat exchange with air in the heat exchanger 76b, the temperature of the hot water decreases. The warm water whose temperature has decreased flows through the high-temperature water path 73 and returns to the cistern 61.

The downstream side of the heating high temperature thermistor 74 in the high temperature water path 73 and the upstream side of the entrance to the cistern 61 in the high temperature water path 73 are connected by a tracking path 77. The tracking path 77 passes through the tracking heat exchanger 58. On the upstream side of the tracking heat exchanger 58 in the tracking path 77, a tracking thermal valve 78 is mounted. The reheating heat valve 78 is controlled by the controller 21.
The bathtub 79 is provided with a suction port 79a and a supply port 79b. The suction port 79 a and the supply port 79 b are connected by a bath circulation path 80. The bath circulation path 80 passes through the reheating heat exchanger 58. As described above, the tracking path 77 also passes through the tracking heat exchanger 58. For this reason, in the reheating heat exchanger 58, heat exchange is performed between the bath circulation path 80 and the reheating path 77. A bath water level sensor 81, a bath circulation pump 82, and a bath water flow switch 84 are mounted on the upstream side of the reheating heat exchanger 58 in the bath circulation path 80. The bath circulation pump 82 is controlled by the controller 21. The bath water level sensor 81 and the bath water flow switch 84 output detection signals to the controller 21. The bath water level sensor 81 detects water pressure. The controller 21 estimates the water level of the hot water stretched on the bathtub 79 from the water pressure detected by the bath water level sensor 81. The bath water flow switch 84 is turned on when water flows through the bath circulation path 80.
On the upstream side of the bath water level sensor 81 in the bath circulation path 80, a bath thermistor 85 that detects the temperature of hot water sucked out from the bathtub 79 is mounted. The detection signal of the bath thermistor 85 is output to the controller 21.

  When the reheating heat valve 78 is opened while the burner 57 and the heating pump 69 are operating, the hot water flows into the reheating path 77 and passes through the reheating heat exchanger 58. When the bath circulation pump 82 is activated, the hot water is sucked out from the suction port 79a of the bathtub 79, flows through the bath circulation path 80, and returns to the bathtub 79 from the supply port 79b again. The hot water flowing through the bath circulation path 80 is heated by the hot water flowing through the chasing path 77 by the chasing heat exchanger 58 and the hot water in the bathtub 79 is chased.

A hot water filling path 25 that connects the middle of the hot-water tap path 63 and the downstream side of the bath circulation pump 82 of the bath circulation path 80 is provided. A solenoid drive type pouring valve 27 and a hot water filling amount sensor 83 are attached to the hot water filling passage 25. The pouring valve 27 is controlled by the controller 21 and opens and closes the hot water filling path 25. The hot water filling amount sensor 83 detects the amount of water flowing through the hot water filling passage 25 to estimate how much the hot water filling operation has been performed to the bathtub 79. The hot water filling amount sensor 83 outputs a detection signal to the controller 21.
When hot water is filled in the bathtub 79, the hot water pouring valve 27 is opened. When the pouring valve 27 is opened, hot water flows from the hot water tap path 63 through the hot water filling path 25 into the bath circulation path 80. Hot water that has flowed into the bath circulation path 80 is supplied to the bathtub 79 from the suction port 79 a and the supply port 79 b, and is filled in the bathtub 79. At this time, the bath circulation pump 82 is not driven, and the water filling operation to the bathtub 79 is performed by the water pressure applied to the water filling passage 25.

In the middle of the low-temperature water path 70, a low-temperature thermistor 94, a floor heating thermal valve 90, and a floor heater 91 are provided. The floor heater 91 warms the floor with warm water flowing through the low-temperature water path 70. When performing floor heating, the floor heating thermal valve 90 is opened, and the hot water is guided to the floor heater 91. The guided hot water warms the floor heater 91. When floor heating is not performed, the floor heating thermal valve 90 is closed. The low temperature thermistor 94 detects the temperature of the hot water flowing through the low temperature water path 70. The detection signal of the low temperature thermistor 94 is output to the controller 21. The floor heating thermal valve 90 is controlled by the controller 21.
The upstream side of the heating terminal thermal valve 75 in the high temperature water path 73 and the downstream side of the floor heater 91 in the low temperature water path 70 are connected by a bypass path 92. When the heating pump 69 is operated with the heating terminal thermal valve 75 and the floor heating thermal valve 90 closed, the hot water in the cistern 61 is sequentially turned to the burner upstream path 71, the burner heat exchanger 60, the high-temperature water path 73, A bypass path 92, a low-temperature water path 70, and a high-temperature water path 73 flow to form a path back to the cistern 61.

In the cogeneration system of the present embodiment, when the hot water in the hot water storage tank 20 is not used for a long time, bacteria that adversely affect the human body such as Legionella bacteria may have propagated in the hot water storage tank 20 during that time. The stored water is sterilized by the procedure shown in FIG.
As shown in FIG. 2, when it is detected that the system power supply is on (YES) in step S10 and the hot water path opening / closing valve 43 is opened in step S12 (NO), the user is at home. Thus, the hot water in the hot water tank 20 is used at an appropriate frequency, and it is considered that there is no need for sterilization treatment, and the routine proceeds to step S36 and normal operation is performed.
In the normal operation of step S36, when the hot water temperature in the hot water storage tank 20 is equal to or higher than the hot water supply set temperature, the mixing unit 24 adjusts the hot water and tap water from the hot water storage tank 20 to the hot water supply set temperature to supply hot water. When the hot water temperature in the hot water tank 20 is lower than the hot water supply set temperature, the hot water is heated to the hot water set temperature by the burner 56 to supply hot water. When the hot water temperature in the hot water storage tank 20 is slightly lower than the hot water supply set temperature, but when this hot water is heated with the minimum heating amount of the burner 56, the hot water temperature exceeds the hot water supply set temperature, and when the hot water is heated with the minimum heating amount of the burner 56 In the mixing unit 24, the temperature is lowered in advance so that the hot water can be supplied at the hot water set temperature so that the hot water set temperature is reached.

If the hot water path opening / closing valve 43 is closed in step S12 (YES), the hot water in the hot water tank 20 is not used. It progresses to step S14 and the time measurement by a timer is started. If it is detected in step S16 that the hot water passage opening / closing valve 43 has been opened (NO), the user is at home and the hot water in the hot water tank 20 is appropriate. It is considered that it is used at a frequency, and the process proceeds to step S36 to perform a normal operation.
While the time is measured by the timer, the hot water path opening / closing valve 43 is closed (YES) in step S16, and if the measured time of the timer becomes 48 hours or longer in step S18 (when YES), 48 hours. As described above, the hot water in the hot water tank 20 is not replaced. If the hot water in the hot water tank 20 is stored for 48 hours or more, there is no possibility that bacteria will propagate. Therefore, it progresses to step S20 and it judges that it is necessary to disinfect the hot water in the hot water tank 20. In order to prevent the hot water before the sterilization treatment in the hot water storage tank 20 from being supplied, in step S22, the hot water path opening / closing valve 43 is kept closed. Even if there is a hot water supply request while the hot water path opening / closing valve 43 is kept closed, the hot water in the hot water storage tank 20 being sterilized is not used for hot water supply. When there is a hot water supply request while the hot water path opening / closing valve 43 is closed, the tap water is heated to the hot water supply set temperature by the burner 56 of the hot water heater 22 to supply hot water.

  In step S24, it is determined whether or not the second flow rate sensor 47 detects a flow rate of 2.7 liters / min or more. While the second flow rate sensor 47 does not detect a flow rate of 2.7 liters / min or higher (NO in step S24), it is determined that the user is absent and sterilization processing is not performed. When the second flow sensor 47 detects a flow rate of 2.7 liters / min or more (when YES in step S24), it is determined that the user has returned home and the hot water tap 64 has been opened, and sterilization processing is performed. To start.

  In step S26, it is determined whether or not the power generation unit 110 is in a power generation operation. Since it is after the return of the user is detected in step S24, there is a high possibility that the power generation operation has been resumed. If the power generation operation is in progress (YES in step S26), the power generation heat recovery operation is executed, and low-temperature water is sent from the lower part of the hot water tank 20 to the power generation unit 110 and heated by the power generation heat in the power generation unit 110. The heated water is returned to the upper part of the hot water tank 20, so that the temperature of the hot water in the hot water tank 20 gradually increases from the upper part. In step S28, the hot water in the hot water storage tank 20 is sterilized by heating with the generated heat until the temperature detected by the lower thermistor 36 provided in the lower part of the hot water storage tank 20 reaches 60 ° C. or higher (until YES). Since the temperature of the hot water in the hot water tank 20 increases from the upper part, if the temperature detected by the lower thermistor 36 is 60 ° C. or higher, the hot water temperature in the entire hot water tank 20 has reached 60 ° C. or higher. Proceed to step S30.

  In step S26, if the power generation unit 110 is not in a power generation operation (NO in step S26), heat sterilization with generated heat cannot be performed. Therefore, the process proceeds to step S40, where the antifreezing heater 123 provided in the heat medium circulation path 124 of the power generation unit 110 is turned on, and the heat medium pump 127 is driven. Accordingly, the hot water in the heat medium circulation path 124 is heated by the antifreezing heater 123 and circulates. In step S42, when the circulation pump 40 provided in the circulation path 128 is driven, low-temperature water is sent out from the lower part of the hot water tank 20 to the power generation unit 110. In the power generation unit 110, the heat medium circulation path 124 The hot water heated by the hot water is returned to the upper part of the hot water tank 20, and the temperature of the hot water in the hot water tank 20 is gradually raised from the upper part. In step S28, the hot water in the hot water storage tank 20 is sterilized by the anti-freezing heater 123 until the temperature detected by the lower thermistor 36 provided in the lower part of the hot water storage tank 20 reaches 60 ° C. or more (until YES). The process proceeds to step S30.

It has been found that harmful bacteria such as Legionella can be killed by heating at 60 ° C. for about 5 minutes. Proceeding to step S30, timing by the timer is started, and the state where the temperature detected by the lower thermistor 36 is 60 ° C. or higher is maintained. If the timer measurement time is 1 hour or longer in step S32 (if YES), the hot water in the entire hot water tank 20 is heated at 60 ° C. or higher for 1 hour. Thereby, it can be considered that the warm water in the entire hot water tank 20 is sufficiently heated and the sterilization treatment is completed. If the sterilization process is completed, the hot water in the hot water tank 20 can be used. Therefore, it progresses to step S34, the closed state of the warm water path | route on-off valve 43 maintained from step S22 is cancelled | released, and normal operation of step S36 is performed. Hot water can be supplied using the hot water in the hot water tank 20 that has been sterilized.
Proceeding to step S38, the processing from step S12 to step S38 is repeated until the system power is turned off. If the system power is turned off (YES in step S38), the process is terminated.

If the hot water in the hot water tank is not used for a long time, harmful bacteria such as Legionella bacteria may propagate in the hot water in the hot water tank. It is necessary to avoid the use of hot water in which bacteria are propagated as it is. Bacteria such as Legionella are vulnerable to heat and are known to die in a relatively short time (about 5 minutes) when heated to 60 ° C. or higher. Heat sterilization is effective for sterilizing hot water in a hot water tank.
If the hot water in the hot water tank is not used for a long period of time, if it is a hot water supply system that heats and sterilizes the hot water in the hot water tank according to the elapsed time and the hot water temperature, the heat sterilization is performed in the absence of the user. It can happen to be done. Even if heat sterilization is performed in the absence, high-temperature hot water after heat sterilization is not used immediately, and eventually the heat is released and the temperature drops. If a user's absence period becomes long, the hot water in a hot water storage tank will be heat-sterilized many times. The act of repeatedly heating and dissipating heat from hot water whose scheduled use time is undecided is nothing but a waste of energy.

In the hot water supply system 10 of the present embodiment, the state in which the hot water in the hot water tank 20 is not used is determined by the open / closed state of the hot water path opening / closing valve 43 provided in the hot water path 42, and the hot water in the hot water tank 20 is If the unused time is 48 hours or more, it is possible that bacteria have propagated in the hot water in the hot water tank 20, and the hot water path opening / closing valve 43 is prohibited from being opened and the hot water in the hot water tank 20 is used. Is prohibited. Opening of the hot water path opening / closing valve 43 is prohibited until the heat sterilization of the hot water in the hot water tank 20 is completed. In the heat sterilization of hot water in the hot water tank 20, it is determined that the flow rate detected by the second flow sensor 47 is 2.7 liters / min or more and the hot water tap 64 is opened, and it is determined that the user is at home. It is done when When the user is absent, heat sterilization is not performed. When the user returns home and the power generation operation is resumed in the power generation unit 110, the hot water in the hot water tank 20 is heated by the generated heat, and the temperature rises to 60 ° C. or higher. When one hour has passed in this state, it is determined that the heat sterilization has been completed, and the prohibition of opening of the hot water path opening / closing valve 43 is released, and the use of hot water in the hot water tank 20 is permitted.
According to the present embodiment, the heat sterilization process of the hot water in the hot water tank 20 is not performed until the user's home is detected, and is performed only once when the user returns home. The hot water in the hot water storage tank 20 is heat sterilized immediately before use, and the hot water heated by the heat sterilization can be used effectively. Since the heat sterilization of the hot water in the hot water tank 20 can be completed only once, the energy efficiency is good, and this one heat sterilization can be performed immediately before using the hot water, which is hygienic.
In the hot water supply system 10 of the present embodiment, heat sterilization is started after confirming that the user is at home. Therefore, even if there is a hot water supply request immediately after the user returns home, the hot water in the hot water storage tank 20 cannot be used for hot water supply unless the heat sterilization is completed. At this time, the hot water path opening / closing valve 43 is closed, and the hot water in the hot water storage tank 20 is not sent out to the mixing unit 24. The water supply inlet 24a of the mixing unit 24 is opened, and tap water is sent out to the mixing unit 24. This tap water is sent to the existing hot water heater 22 in the hot water supply system 10, and heated to a hot water supply set temperature to be supplied with hot water. Although heat energy is consumed for heating tap water, the hot water in the hot water tank 20 is heated in the absence of the user, and as a result, the heat may be dissipated without using the hot water. Compared to other systems, energy efficiency is much improved.
According to the present embodiment, hot water in the hot water storage tank 20 that has not been used for a long time is subjected to heat sterilization at an appropriate timing and without wasting energy and resources, and the hot water supply system 10 is used in a sanitary manner. be able to.

(Example 2)
A second embodiment of the hot water storage type hot water supply system of the present invention will be described with reference to the drawings. This embodiment is also a cogeneration system incorporating the hot water storage type hot water supply system of the present invention. The configuration of the cogeneration system of this embodiment is the same as that of the cogeneration system of the first embodiment described in detail with reference to FIG. In the first embodiment, the hot water in the hot water tank is sterilized by heating when the hot water is not used for a long period of time, but in this embodiment, the hot water in the hot water tank is replaced. . Therefore, here, only the replacement process of the stored water will be described, and the description of the rest will be omitted. In this embodiment, the reference numerals used in the first embodiment are used as they are.
In the cogeneration system of the present embodiment, when the hot water in the hot water storage tank 20 is not used for a long time, bacteria that adversely affect the human body such as Legionella bacteria may have propagated in the hot water storage tank 20 during that time. The replacement process of the stored water is performed according to the procedure shown in FIG.

  As shown in FIG. 3, the processing from step S50 to step S58 is the same as the processing from step S10 to step S18 of the first embodiment, and thus description thereof is omitted. When it is detected that the hot water path opening / closing valve 43 is continuously closed for 48 hours or longer (steps S52 to S58), the process proceeds to step S60, and it is determined that the storage water needs to be replaced. In order to prevent the hot water in the hot water storage tank 20 where bacteria may have propagated from being supplied, in step S62, the hot water path opening / closing valve 43 is kept closed. Even if there is a hot water supply request while the hot water path opening / closing valve 43 is kept closed, the hot water in the hot water storage tank 20 where bacteria may have propagated is not used for hot water supply. When there is a hot water supply request while the hot water path opening / closing valve 43 is closed, the tap water is heated to the hot water supply set temperature by the burner 56 of the hot water heater 22 to supply hot water.

  In step S64, it is determined whether or not the second flow rate sensor 47 detects a flow rate of 2.7 liters / min or more. While the second flow rate sensor 47 does not detect a flow rate of 2.7 liters / min or higher (NO in step S64), it is determined that the user is absent, and the storage water replacement process is not performed. When the second flow rate sensor 47 detects a flow rate of 2.7 liters / min or more (when YES at step S64), it is determined that the user has returned home and the hot water tap 64 has been opened, Start the replacement process.

In step S66, the hot water drainage path opening / closing valve 49 provided in the hot water drainage path 41 is opened. As a result, the hot water in the upper part of the hot water tank 20 is drained from the end of the hot water drain path 41. At the same time, tap water is introduced from the lower part of the hot water tank 20. When the hot water drainage path opening / closing valve 49 is opened, the process proceeds to step S68, and integration of the flow rate detected by the hot water flow rate sensor 46 provided in the hot water path 42 is started. Proceeding to step S70, the warm water drainage path opening / closing valve 49 is opened until the integrated flow rate of the hot water flow rate sensor 46 is equal to or greater than [capacity of hot water tank 20 (150 liters) + α (10 liters)] (until YES). The hot water in the hot water tank 20 is drained. α is a value larger than the piping capacity of the hot water passage 42. Thereby, the hot water in the hot water tank 20 is replaced with fresh water. Accordingly, the process proceeds to step S72, and the hot water drainage path opening / closing valve 49 is closed. And it progresses to step S74, the closed state of the hot water path | route on-off valve 43 maintained from step S62 is cancelled | released, and normal operation of step S76 is performed. In normal operation, hot water can be supplied using fresh water in the hot water storage tank 20 that has been replaced.
Proceeding to step S78, the processing from step S52 to step S78 is repeated until the system power is turned off. If the system power is turned off (YES in step S78), the process ends.

In order to use the hot water storage hot water supply system in a sanitary manner, it is also an effective means to replace the hot water when the hot water in the hot water storage tank has not been used for a long period of time.
If the hot water in the hot water tank is not used for a long period of time, the hot water in the hot water tank can be replaced while the user is not present. It can happen that a change is made. Even if the replacement is performed in the absence, the water filled in the hot water storage tank is not used immediately, and if a further time elapses after the replacement, the replacement may be necessary again. If a user's absence period becomes long, the hot water in a hot water tank will be replaced many times. The act of repeating the replacement of hot water whose scheduled use time is undecided many times is nothing but a waste of resources.

In the hot water supply system 10 of the present embodiment, the state in which the hot water in the hot water tank 20 is not used is determined by the open / closed state of the hot water path opening / closing valve 43 provided in the hot water path 42, and the hot water in the hot water tank 20 is If the unused time is 48 hours or more, it is possible that bacteria have propagated in the hot water in the hot water tank 20, and the hot water path opening / closing valve 43 is prohibited from being opened and the hot water in the hot water tank 20 is used. Is prohibited. Opening of the hot water path opening / closing valve 43 is prohibited until the replacement of the hot water in the hot water tank 20 is completed. When the hot water in the hot water storage tank 20 is replaced, it is determined that the flow rate detected by the second flow sensor 47 is 2.7 liters / min or more and the hot water tap 64 is opened, and it is determined that the user is at home. It is done when When the user is absent, the hot water in the hot water tank 20 is not replaced. When the detected flow rate of the hot water flow sensor 46 reaches [hot water storage tank capacity (150 liters) + α (10 liters)], it is determined that the replacement of the hot water in the hot water storage tank 20 has been completed, and the prohibition of opening the hot water path opening / closing valve 43 is released. The use of hot water in the hot water storage tank 20 (water immediately after replacement) is permitted.
According to the present embodiment, replacement of hot water in the hot water tank 20 is not performed until the user's home is detected, and is performed only once when the user returns home. Since the hot water in the hot water tank 20 can be replaced once, the consumption of resources can be minimized, and this single replacement can be performed immediately before use.
According to the present embodiment, the hot water in the hot water storage tank 20 that has not been used for a long time is replaced at an appropriate timing and without wasting energy and resources, and the hot water supply system 10 is used in a sanitary manner. be able to.

(Example 3)
A third embodiment of the hot water storage type hot water supply system of the present invention will be described with reference to the drawings. This embodiment is also a cogeneration system incorporating the hot water storage type hot water supply system of the present invention. The configuration of the cogeneration system of this embodiment is the same as that of the cogeneration system of the first embodiment described in detail with reference to FIG. In 1st Example, when the warm water in a hot water storage tank is not used over a long period of time, the sterilization process by heating is performed. In the second embodiment, when the hot water in the hot water storage tank has not been used for a long period of time, the replacement process of the stored water is performed. In this embodiment, when the hot water in the hot water tank is not used for a long period of time, either the hot water heat sterilization process in the hot water tank or the hot water replacement process in the hot water tank is performed. Accordingly, here, a description is mainly given of a process for selecting these processes, and a description of the other processes is omitted. In this embodiment, the reference numerals used in the first embodiment are used as they are.
In the cogeneration system of the present embodiment, when the hot water in the hot water storage tank 20 is not used for a long time, bacteria that adversely affect the human body such as Legionella bacteria may have propagated in the hot water storage tank 20 during that time. The process shown in FIG. 4 is performed.

As shown in FIG. 4, the processing from step S90 to step S98 is the same as the processing from step S10 to step S18 in the first embodiment (both the processing from step S50 to step S58 in the second embodiment). Therefore, the description is omitted. When it is detected that the hot water path opening / closing valve 43 is continuously closed for 48 hours or longer (steps S92 to S98), the process proceeds to step S100.
In step S100, it is further determined whether or not the timer measurement time is 120 hours or longer. If the hot water path opening / closing valve 43 is closed in step S96 (still remains YES), and the timer measurement time is 120 hours or longer (if YES), the hot water in the hot water tank 20 has not been replaced for 120 hours or longer. It will be. If the hot water in the hot water storage tank 20 remains stored for 120 hours or more, there is a high possibility that bacteria will propagate. Therefore, it progresses to step S102, judges that it is necessary to replace | exchange the hot water in the hot water storage tank 20, and performs the replacement | exchange process of stored water. The storage water replacement process is the same as the process from step S60 to step S72 of FIG. 3 described in the second embodiment, and thus the description thereof is omitted.
If the measurement time of the timer is less than 120 hours (if NO), even if bacteria are propagated in the hot water in the hot water tank 20, the state that can be used for hot water supply can be recovered by the heat sterilization treatment. It progresses to step S104 and the heat sterilization process of stored water is performed. The heat sterilization process of the stored water is the same as the process from step S20 to step S32 of FIG. 2 described in the first embodiment, and thus description thereof is omitted.

  In step S102, the stored water is replaced, or in step S104, the stored water is heat sterilized, and the process proceeds to step S106. The processing from step S106 to step S110 is the same as the processing from step S34 to step S38 in the first embodiment (same as the processing from step S74 to step S78 in the second embodiment), so the explanation will be given. Omitted.

According to the present embodiment, when the hot water in the hot water tank 20 is not used for 48 hours or more, if the hot water in the hot water tank 20 is not stored for 120 hours, the hot water in the hot water tank 20 is used. If the time during which the hot water is stored is 120 hours or longer at 60 ° C. or higher for 1 hour, the hot water in the hot water tank 20 is replaced. When the hot water in the hot water tank 20 has not been used for a long time, immediately before using the hot water in the hot water tank 20, an appropriate treatment that matches the state of the hot water in the hot water tank 20 is performed only once, and the hot water supply system 10 Can be used hygienically.
According to the present embodiment, the hot water in the hot water storage tank 20 that has not been used for a long period of time can be replaced at an appropriate timing and without any waste of energy or resources, either the replacement process or the heat sterilization process. The hot water supply system 10 can be used hygienically.

Specific examples of the present invention have been described in detail above, but these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above.
For example, in the first to third embodiments, it is determined whether or not the user is at home based on the change in the detected flow rate of the second flow sensor 47. Instead, for example, the change in the detection value of the power sensor, Detection of device operation by a person, detection by a human body sensor, etc. can also be used. Further, when a plurality of these events are observed and there is some change in at least one of these events, there may be a predetermined change.
In the first and third embodiments, when detecting the temperature of the hot water in the lower part of the hot water tank 20, the forward thermistor 44 provided in the circulation outward path 128b may be used instead of the lower thermistor 36.
In the first embodiment and the third embodiment, when the hot water in the hot water tank 20 is sterilized by heating, the hot water in the hot water tank 20 is heated by power generation heat. And the structure which uses the heating by the antifreezing heater 123 together may be used.
In the third embodiment, an appropriate one of the replacement process and the heat sterilization is selected according to the time during which the hot water in the hot water tank 20 is stored. This selection may be manually set by the user.
In addition, the technical elements described in the present specification or the drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology illustrated in the present specification or the drawings achieves a plurality of objects at the same time, and has technical utility by achieving one of the objects.

The systematic diagram of the cogeneration system which concerns on 1st Example. The flowchart which shows the process of the hot water in the hot water storage tank of a present Example. The flowchart which shows the process of the hot water in the hot water storage tank of 2nd Example. The flowchart which shows the process of the hot water in the hot water storage tank of 3rd Example.

Explanation of symbols

10: Hot water supply system 20: Hot water storage tank 22: Hot water heater 24: Mixing unit 36: Lower thermistor 41: Hot water drainage path 42: Hot water path 43: Hot water path opening / closing valve 44: Outward thermistor 44
46: Hot water flow sensor 47: Second flow sensor 49: Hot water drainage path opening / closing valve 64: Hot water tap 65: Hot water thermistor 110: Power generation unit 123: Freezing prevention heater 124: Heat medium circulation path

Claims (3)

A hot water tank for storing hot water,
Heating means for heating the hot water stored in the hot water tank;
A mixing unit that mixes hot water and tap water from a hot water tank and adjusts the mixing ratio;
A hot water path connecting the hot water tank and the mixing unit;
An on-off valve that opens and closes the hot water path;
Temperature detecting means for detecting the temperature of hot water in the hot water tank;
Use state determining means for determining whether or not the hot water in the hot water tank is being used; and
A first time measuring means for measuring the elapsed time from when the use state determining means determines that the hot water in the hot water tank is not in use;
At-home determination means for determining whether or not the user is at home;
A second time measuring means for measuring a time during which the temperature of the hot water detected by the temperature detecting means is equal to or higher than a predetermined temperature set higher than the sterilizable temperature ;
When the time measured by the first time measuring means is equal to or longer than the first predetermined time, the opening of the on-off valve is prohibited, and the home determination means determines that the user is at home while the opening of the on-off valve is prohibited. , perform the heat sterilization treatment to maintain the temperature of hot water that time measured by the second timer means is the temperature detecting means until the Do and the second predetermined time is detected more than the predetermined temperature, then, the opening of the opening and closing valve A hot water storage type hot water supply system comprising: an on-off valve control means for releasing the prohibited state. A hot water tank for storing hot water,
A mixing unit that mixes hot water and tap water from a hot water tank and adjusts the mixing ratio;
A hot water path connecting the hot water tank and the mixing unit;
An on-off valve that opens and closes the hot water path;
Use state determining means for determining whether or not the hot water in the hot water tank is being used; and
A first time measuring means for measuring the elapsed time from when the use state determining means determines that the hot water in the hot water tank is not in use;
At-home determination means for determining whether or not the user is at home;
A replacement means for replacing the hot water in the hot water tank;
Flow rate detection means for detecting the flow rate of the water replaced by the replacement means;
When the time measured by the first time measuring means is equal to or longer than the first predetermined time, the opening of the on-off valve is prohibited, and the home determination means determines that the user is at home while the opening of the on-off valve is prohibited. , closing the Swapping flow rate detected by the flow rate detecting means executes the incoming exchange water exchange process process hot water of the hot water storage tank by Swapping means to the ing and predetermined flow rate, then, to release the open prohibition state of the on-off valve A hot water storage hot water system comprising valve control means.   The hot water storage system according to claim 1 or 2, wherein the at-home determination means includes means for detecting a predetermined change in the driving state, and determines that the user is at home when the predetermined change is detected. Hot water system.

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