JP2007205590A - Hot water storage type water heater - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hot water storage type water heater capable of minimizing energy necessary for sterilizing treatment, and supplying hot water even in the sterilizing treatment. <P>SOLUTION: In a hot water supply passage 11 from a hot water storage tank 7 to a hot water supply plug 8 through an auxiliary heat source unit 17 and a mixing valve 21, a sub-tank 19 is disposed between the auxiliary heat source unit 17 and the mixing valve 21, and a time required for the hot water to flow from the auxiliary heat source unit 17 to the mixing valve 21 through the sub-tank 19 is determined to be longer than a necessary sterilizing time. Further a bypass passage 20 is formed in parallel with the sub-tank 19, and a three-way valve 18 is disposed to switch a hot water passage to either of the sub-tank 19 and the bypass passage 20. When the amount of use of hot water in the hot water storage tank 7 becomes smaller than requirements for a specific period, the three-way valve 18 is switched to a sub-tank 19 side, and the hot water is heated higher than a sterilizing temperature by the auxiliary heat source unit 17. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a hot water storage hot water supply apparatus having a hot water storage tank for storing heat of a combined heat and power supply device, and in particular, when hot water in a hot water storage tank is not used for a long period of time, hot water containing Legionella bacteria is stored in the hot water storage tank. The present invention relates to a hot water storage type hot water supply apparatus that prevents supply.

  In recent years, with the widespread use of cogeneration systems, waste heat generated from a combined heat and power generator that generates heat and electric power is stored as hot water in a hot water storage tank, and the hot water in the hot water storage tank is used for hot water supply, bath filling, heating, etc. Development of a hot water storage type hot water supply device that is designed to be used is in progress. In such a hot water storage type hot water supply apparatus, since hot water is stored in the hot water storage tank, various germs may propagate in the hot water tank. Therefore, it is necessary to sterilize the hot water storage tank periodically. In particular, it is absolutely necessary to avoid Legionella bacteria that are harmful to the human body from being mixed in hot water supplied with hot water. Therefore, a hot water storage type hot water supply device having a function of sterilizing hot water in the hot water storage tank is required.

  As a technique for sterilizing the hot water in the hot water storage tank, a technique described in Patent Document 1 is known.

  FIG. 6 is a diagram showing a configuration of a conventional hot water storage type hot water supply apparatus described in Patent Document 1. In FIG. 6, a hot water storage type hot water supply apparatus 100 includes a hot water storage tank 101 for storing exhaust heat generated in the combined heat and power supply apparatus 102. The exhaust heat is recovered into hot water circulating in the exhaust heat circulation path 103 and supplied to the hot water circulating in the circulation heating path 105 in the exhaust heat heat exchanger 104.

  In the circulating heating path 105, water (hot water) circulates from the lower part to the upper part of the hot water storage tank 101. The low temperature water in the lower part of the hot water storage tank 101 is absorbed by the exhaust heat exchanger 104 to become high temperature water (hot water), and is returned to the upper part of the hot water storage tank 101. This hot water storage tank 101 is a stratified hot water storage hot water storage layer, and the hot water storage tank 101 forms a boundary between the high temperature layer composed of high temperature water in the upper part, the low temperature layer composed of low temperature water in the lower part, and both layers. A temperature stratification consisting of a boundary layer is formed. As heat is stored, the high temperature layer expands from the upper part of the tank toward the lower part, and the low temperature layer shrinks.

  The circulation heating path 105 is provided with an auxiliary heat source device 112. When the temperature of the hot water supplied from the circulating heating path 105 to the hot water storage tank 101 is lower than the target temperature, the auxiliary water source 112 heats the hot water in the circulating heating path 105 to raise the temperature to the target temperature.

  When hot water is discharged from the hot water storage layer 101 to the hot water tap 106 or the bathtub 107, tap water is supplied to the hot water storage tank 101 through the water supply passage 108. Since low temperature water is supplied to the lower part of the hot water storage tank 101, hot water having high temperature is led out from the upper part of the hot water storage tank 101 to the hot water supply passage 109. A mixing valve 110 is provided in the middle of the hot water supply passage 109, and tap water supplied from the branch water supply passage 111 and hot water supplied from the hot water storage tank 101 are mixed at an appropriate ratio according to the hot water temperature. The temperature is adjusted. The hot water whose temperature has been adjusted is supplied to the hot water tap 106 through the branch hot water supply passage 109a or supplied to the bathtub 107 through the branch hot water supply passage 109b.

  In the hot water storage type hot water supply apparatus 100 as described above, the sterilization operation of the hot water storage tank 101 is performed as follows.

  First, a timer (not shown) is used to measure the time during which the hot water supply is stopped. When the time measured by the timer exceeds a predetermined time α (for example, 100 hours), it is determined that the hot water in the hot water storage tank 101 has not been used for a long period of time and sterilization is necessary, and sterilization is started. .

  In the sterilization process, first, the mixing valve 110 is switched so that the branch water supply path 111 side is fully opened and the hot water supply path 109 side is fully closed, so that hot water in the hot water storage tank 101 is not supplied. Next, the circulation pump 113 of the circulation heating path 105 is started, and the water (hot water) in the hot water storage tank 101 is circulated through the circulation heating path 105. In this state, the auxiliary heat source device 112 is activated to heat the water circulating in the circulation heating path 105 to a preset sterilization temperature (for example, 75 ° C. or higher). Thereby, the high temperature layer in the hot water storage tank 101 is expanded. Finally, when the hot water temperature in the lower part of the hot water storage tank 101 reaches the sterilization temperature, the auxiliary heat source device 112 and the circulation pump 113 are stopped and left for a certain period of time.

Usually, Legionella is known to die within 10 to 15 minutes at 60 ° C. and within 5 seconds at 70 ° C. Therefore, Legionella in the hot water storage tank can be killed by leaving it for the above time at a temperature equal to or higher than the sterilization temperature.
JP 2004-263912 A

  In the conventional hot water storage type hot water supply apparatus, in order to sterilize the hot water storage tank, it is necessary to heat all the water in the hot water storage tank to the sterilization temperature. Generally, hot water storage tanks are designed with a large amount of hot water storage in order to increase the heat capacity. Therefore, a considerable amount of heat is required to heat all the water in the hot water storage tank above the sterilization temperature.

  Immediately after the hot water tank is sterilized, the hot water tank is filled with hot hot water. If hot water is not used continuously, the heat in the hot water tank is lost due to natural heat dissipation. Is called. Therefore, the heat dissipation loss of the entire system is increased, which contributes to a reduction in energy saving performance.

  In addition, if it is attempted to heat the hot water storage tank above the sterilization temperature, the time required for the heating also becomes longer. During the sterilization process, the hot water in the hot water storage tank cannot be used. Therefore, even if a request to resume hot water supply or hot water filling occurs during the sterilization process, it is necessary to wait until the sterilization process is completed. Therefore, there is a problem that even if it is attempted to resume hot water supply or hot water filling, there is a case where the user waits for a certain period of time.

  Accordingly, an object of the present invention is to provide a hot water storage type hot water supply apparatus that can minimize the energy required for the sterilization process of hot water in a hot water storage tank and that does not prevent hot water supply or hot water filling when performing the sterilization process. There is to do.

A first configuration of a hot water storage type hot water supply apparatus according to the present invention includes a hot water storage tank for storing hot water,
A water supply channel for supplying water to the hot water storage tank;
An exhaust heat circulation path for supplying heat generated in the combined heat and power supply device to the hot water storage tank by circulating the water in the lower portion of the hot water storage tank to a combined heat and power generation device that generates heat and electric power and returning it to the upper portion of the hot water storage tank; ,
A hot water supply passage leading out hot water inside the hot water storage tank to a hot water tap or bathtub; and
In the hot water storage type hot water supply device equipped with
A flow rate sensor for detecting a flow rate of hot water discharged from the hot water storage tank;
An auxiliary heat source that is provided in the hot water supply path and heats hot water in the hot water supply path;
A first temperature sensor for detecting a temperature Θ1 of hot water in the hot water supply channel downstream of the auxiliary heat source;
A sub tank provided on the downstream side of the auxiliary heat source device of the hot water supply path;
A bypass path provided to form a water path that is connected to the hot water supply path at both ends and bypasses the sub tank;
A three-way valve provided at a branch portion of the hot water supply path and the bypass path on the upstream side of the sub tank, for switching a flow path of hot water led out from the hot water storage tank to the sub tank side or the bypass path;
A controller for controlling the switching of the three-way valve and the operation of the auxiliary heat source device,
The controller is
Usage amount storage means for storing the usage amount of hot water in the hot water storage tank per unit time;
Usage amount integrating means for integrating the flow rate detected by the flow rate sensor per unit time and storing it in the usage amount storage means;
When hot water supply or hot water filling is performed, the amount of hot water in the hot water storage tank for a predetermined period T1 before that time is integrated, and if the integrated value Q is less than or equal to a predetermined threshold value Q1, the operating state is sterilized. An integrated value of the amount of hot water used in the hot water storage tank from the time when the integrated value Q is equal to or greater than a predetermined threshold value Q1 and the operating state is last switched to the sterilized state to the time point. If Q ′ is greater than or equal to a predetermined threshold value Q1 ′, a sterilization process determining means for setting the operating state to a normal state;
When the operation state is the sterilization state, the three-way valve is switched so that the hot water flow path is on the sub-tank side, and the auxiliary heat source is activated to heat the hot water temperature Θ1 to a predetermined sterilization temperature Θs or higher. And sterilization processing means for performing control to switch the three-way valve so that the flow path of the hot water is on the bypass path side when the operation state is the normal state.

  According to this configuration, when the amount Q of hot water stored in the hot water storage tank used within the predetermined period T1 is equal to or less than the predetermined threshold value Q1, the operation state is sterilized when hot water is supplied or hot water is filled next time. The processing state is assumed. In the sterilization treatment state, the temperature of the hot water in the hot water supply passage is heated by the auxiliary heat source so as to be equal to or higher than the sterilization temperature (predetermined sterilization temperature Θs). The hot water that has exited the auxiliary heat source is led to a hot water tap or a bathtub via a sub tank. At this time, the flow volume of the hot water supply path downstream from the outlet of the auxiliary heat source device is increased by the volume of the sub tank. Therefore, since the time for reaching the warm water from the auxiliary heat source outlet to the sub tank outlet becomes longer, the time during which the hot water temperature is maintained above the sterilization temperature Θs can be maintained longer than the time required for sterilization. .

  Sterilization is performed by heating the amount of hot water used for hot water supply or hot water filling when hot water supply or hot water supply occurs, so the heating energy required for sterilization can be kept to a minimum. it can. Moreover, since there is no operation | movement which heats the whole hot water storage tank beyond sterilization temperature, if there exists a hot water supply or hot water filling request | requirement, the hot water in a hot water tank can be discharged immediately without making it wait.

On the other hand, when the following conditions (1) and (2) are met, the operation state is switched from the sterilization state to the normal state:
(1) The integrated value Q of the amount of hot water used in the hot water storage tank in a predetermined period T1 before the present time is not less than a predetermined threshold value Q1;
(2) The integrated value Q ′ of the amount of hot water used in the hot water storage tank from the time when the operation state was last switched to the sterilization state to the time is equal to or greater than a predetermined threshold value Q1 ′.

  By setting the threshold value Q1 ′ to be equal to or greater than the capacity of the hot water storage tank, the operating state is switched from the sterilization state to the normal state after all the hot water stored in the hot water storage tank that requires sterilization is used. be able to.

  Here, the capacity of the sub-tank is adjusted by adjusting the temperature of the hot water that has exited the auxiliary heat source from the sub-tank outlet or downstream by mixing it with a mixing valve (cold water and hot water mixed at an appropriate ratio). The time to reach the valve) is sufficiently longer than the time required to maintain the hot water temperature above the sterilization temperature Θs in order to kill the bacteria (hereinafter referred to as “necessary sterilization time”). Set to capacity. Specifically, the flow rate of the hot water supply path when the hot water tap or the hot water supply valve of the bathtub is fully opened is Fmax, the required sterilization time is Tp, the capacity of the sub tank is Vs, and the hot water supply path from the outlet of the auxiliary heat source device to the mixing valve (sub tank) The capacity Vs of the sub tank needs to be set so that Vs ≧ F · Tp−Vw.

  The “predetermined period T1” is a time when it becomes necessary to perform sterilization control of bacteria, and is a time that is appropriately determined according to the environment in which the hot water storage type hot water supply apparatus is installed. Therefore, it is preferable that the setting value can be arbitrarily set from the outside by the user or the administrator of the apparatus.

  The “predetermined threshold value Q1” is a maximum value of the usage amount within the period T1 in which it is necessary to perform sterilization control of bacteria, and is appropriately determined according to the environment where the hot water storage type hot water supply apparatus is installed. Therefore, it is preferable that the setting value can be arbitrarily set from the outside by the user or the administrator of the apparatus.

  The “predetermined sterilization temperature Θs” is a temperature necessary for sterilization of bacteria, and is determined according to a temperature at which the target bacteria can be sterilized.

  The “predetermined threshold value Q1 ′” may be set to the amount of hot water used until it is sufficiently considered that all of the hot water in the hot water storage tank has been used after it is determined that the hot water needs to be sterilized. Specifically, as described above, it may be set to an amount about the capacity of the hot water storage tank or more.

  In the present invention, a drain valve for draining the water in the sub tank is provided, and the controller opens the drain valve when a predetermined time T1 ′ has elapsed since the last hot water supply or hot water filling was completed. In addition, it is possible to perform control to drain the water in the sub tank.

  With this configuration, it is possible to prevent hot water (water) from staying in the sub tank for a long period of time, and reliably prevent the occurrence and increase of Legionella bacteria in the sub tank. In addition, since a sub tank has a capacity | capacitance smaller than a hot water storage tank (heat capacity is small), the temperature of the warm water in a sub tank falls comparatively early. In addition, the probability of occurrence of Legionella is small because of its small capacity. Therefore, compared with the hot water storage tank, since the time until the risk of increasing Legionella in the sub-tank becomes high, it is generally possible to satisfy T1 ′ ≧ T1.

  According to a second configuration of the hot water storage type hot water supply apparatus according to the present invention, in the first configuration, the sterilization processing unit controls whether to switch the three-way valve. Instead, the three-way valve is switched so that the hot water flow path is always on the sub-tank side.

  According to this configuration, when hot water filling is performed, the three-way valve is always switched so that the flow path of the hot water is on the sub tank side. Normally, hot water filling requires hot water enough to fill the bathtub, so a large amount of hot water in the hot water storage tank is used. Therefore, the hot water in the sub-tank is completely replaced when the hot water is filled, so that the hot water can be prevented from staying in the sub-tank for a long time. Therefore, the situation where Legionella bacteria are generated and increased in the sub tank can be prevented.

A third configuration of the hot water storage type hot water supply apparatus according to the present invention is the first or second configuration, wherein the first configuration is provided in the hot water supply passage on the downstream side of the sub tank and controls the flow rate of the hot water flowing through the hot water supply passage. A flow control valve of
A flow rate sensor for detecting a flow rate F of hot water flowing through the hot water supply path,
When the hot water supply or hot water filling is started and the operation state is a sterilization state, the sterilization means is configured such that the flow rate F detected by the flow rate sensor is changed from the outlet of the auxiliary heat source to the first flow rate control valve. The first flow rate control valve is controlled so that the time during which the hot water passes through the hot water supply path is equal to or less than the flow rate F1, which is a predetermined time Tp required for sterilization.

  According to this configuration, when sterilization of hot water is necessary, the first flow rate is controlled from the outlet of the auxiliary heat source device by suppressing the flow rate of hot water discharged using the first flow control valve to F1 or less. The time required for passing warm water to the control valve is compensated so as to be longer than the required sterilization time Tp. Therefore, the restriction on the capacity of the sub tank (restriction that the capacity must be sufficient to ensure the necessary sterilization time Tp) is relaxed, and the capacity of the sub tank can be reduced.

  If the capacity of the sub-tank is small, the time until the hot water that has exited the hot water storage tank reaches the hot water tap or the bathtub is shortened, so that the use of the hot water in the hot water storage tank can be started early after the start of hot water supply.

  In addition, if the capacity of the sub tank is small, the probability that bacteria are generated and increased in the sub tank can be reduced.

  Here, the “predetermined time Tp required for sterilization” refers to the time required to maintain the temperature Θ1 of hot water at or above the predetermined sterilization temperature Θs for sterilization. The flow rate F1 can be obtained by F1 = V / Tp, where V is the volume in the hot water supply path from the auxiliary heat source outlet to the flow rate control valve and in the sub tank.

According to a fourth configuration of the hot water storage type hot water supply apparatus according to the present invention, in the third configuration, an adjustment water channel connecting the water supply channel and the sub-tank downstream side of the hot water supply channel,
A second flow control valve for adjusting a flow rate of water flowing through the adjustment water channel;
A mixing valve that is provided at a connection portion between the adjustment water channel and the hot water supply channel, and adjusts a mixing ratio of hot water from the hot water supply channel and water from the adjustment water channel;
The first flow control valve is the mixing valve;
When the hot water supply or hot water filling is started and the operation state is a sterilization state, the sterilization processing means is configured such that the flow rate F detected by the flow rate sensor is from the auxiliary heat source outlet to the flow rate control valve. The mixing valve and the second flow control valve are set so that the time during which the warm water passes through the passage is equal to or less than the flow rate F1, which is a predetermined time Tp required for sterilization, and the hot water temperature discharged is a predetermined set temperature. It is characterized by controlling.

  With this configuration, the configuration of the apparatus can be simplified by using the mixing valve as the first flow control valve.

  Here, the “predetermined set temperature” is a temperature set by a user by a remote controller or the like at the start of hot water supply or hot water filling, or set in advance as a fixed value.

  As described above, according to the present invention, the heating energy required to sterilize the hot water in the hot water storage tank can be minimized. Therefore, energy saving performance (energy efficiency) in the hot water storage type hot water supply apparatus can be improved as compared with the conventional case. In addition, because there is no time zone for prohibiting hot water from the hot water storage tank for sterilization of hot water, regardless of whether there is a need for sterilization, The hot water in the hot water tank can be immediately discharged.

  Further, when hot water filling is started, it is possible to prevent the hot water from staying in the sub tank for a long time by always switching the three-way valve so that the flow path of the hot water is on the sub tank side. Therefore, it is possible to prevent occurrence of a situation in which Legionella bacteria are generated or increased in the sub tank.

  Moreover, the capacity | capacitance of a subtank can be made small by providing a 1st flow control valve in the subtank downstream, and restrict | limiting the flow volume of a hot water supply path with a 1st flow control valve when a sterilization process is required. This makes it possible to start using hot water in the hot water storage tank early after the start of hot water.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

  FIG. 1 is a diagram illustrating an overall configuration of a hot water storage type hot water supply apparatus 1 according to a first embodiment of the present invention. The hot water storage type hot water supply apparatus 1 of the present embodiment is used in a cogeneration system.

  The cogeneration system shown in FIG. 1 includes a hot water storage hot water supply device 1, a combined heat and power supply device 2, an exhaust heat circulation path 3, a cooling water circulation pump 4, a circulation heating circuit 5, and an exhaust heat exchanger 6. The combined heat and power supply device 2 is a device that extracts heat generated simultaneously with power generation as exhaust heat, and includes a fuel cell, an engine power generation device, and the like. The exhaust heat circulation path 3 is a circuit through which cooling water for extracting the exhaust heat generated in the combined heat and power supply device 2 circulates. The cooling water circulation pump 4 is a pump for circulating cooling water in the exhaust heat circulation path 3. The circulation heating circuit 5 is a circuit that absorbs heat from the cooling water circulating in the exhaust heat circulation path 3 and circulates water (hot water) for supplying heat to the hot water storage hot water supply device 1. The exhaust heat exchanger 6 is a heat exchanger that performs heat exchange between the cooling water in the exhaust heat circulation path 3 and the water in the circulation heating circuit 5.

  The hot water storage type hot water supply device 1 is a device for storing the heat supplied from the combined heat and power supply device 2 as hot water in the hot water tank 7 and supplying hot water to the hot water tap 8 and the bathtub 9 according to the user's request. .

  The hot water storage type hot water supply apparatus 1 includes a hot water storage tank 7, a water supply path 10, an adjustment water path 10 a, a hot water supply path 11, branch hot water supply paths 11 a and 11 b, a pressure reducing valve 12, a check valve 14, a pressure release path 15, a relief valve 16, and an auxiliary heat source. 17, three-way valve 18, sub-tank 19, bypass path 20, mixing valve 21, hot-water valve 22, tank temperature sensors 23 a to 23 d, flow sensor 24, BU thermistor 25, hot water thermistor 26, tank water circulation pump 27, and controller 28. It has.

  The hot water storage tank 7 is a tank that stores heat generated in the combined heat and power supply device 2 as hot water. The hot water storage tank 7 uses a stratified hot water storage system. The stratified hot water storage system is a system in which hot hot water recovered by exhaust heat is slowly poured into the upper part of the hot water storage tank 7 and stored so as not to be mixed with the low temperature water at the lower part of the hot water storage tank 7.

  Four tank temperature sensors 23a, 23b, 23c, and 23d are provided at different heights from the upper part to the lower part of the hot water tank 7. These temperature sensors 23 a, 23 b, 23 c, and 23 d detect the temperature of hot water (water) at respective heights in the hot water storage tank 7.

  Both ends of the circulating heating circuit 5 are connected to the lower and upper portions of the hot water storage tank 7. The low-temperature water (hot water) in the lower part of the hot water storage tank 7 is led to the circulation heating circuit 5 by the tank water circulation pump 27, and the exhaust heat from the combined heat and power supply device 2 is given in the exhaust heat exchanger 6. Then, the hot water that has become hot is returned to the upper part of the hot water storage tank 7. As a result, the low temperature layer at the bottom of the hot water storage tank 7 is reduced, the high temperature layer at the top of the hot water storage tank 7 is expanded, and heat is stored in the hot water storage tank 7.

  A water supply path 10 for supplying tap water to the hot water storage tank 7 is connected to the bottom of the hot water storage tank 7. A pressure reducing valve 12 and a check valve 14 are attached to the water supply channel 10 from the water supply side. The pressure reducing valve 12 is a valve for reducing the tap water pressure of tap water. The check valve 14 is a valve for preventing the water (hot water) in the hot water storage tank 7 from flowing back to the water supply side.

  A hot water supply path 11 for supplying hot water from the hot water storage tank 7 to the hot water tap 8 or the bathtub 9 is connected to the upper part of the hot water storage tank 7. The end portion of the hot water supply passage 11 is branched into two branch hot water supply passages 11a and 11b. The branch hot water supply path 11 a is connected to the hot water tap 8, and the branch hot water supply path 11 b is connected to the bathtub 9 via the hot water valve 22. The hot water valve 22 fills the bathtub 9 with hot water supplied from the hot water supply passage 11. The branch hot water supply passage 11b is provided with a backflow prevention device (not shown) so that the water in the bathtub 9 does not flow backward to the hot water storage tank 7 side when the water is shut off.

  In the middle of the hot water supply path 11, a flow rate sensor 24, an auxiliary heat source device 17, a BU thermistor 25, a three-way valve 18, a sub tank 19, a mixing valve 21, and a hot water thermistor 26 are provided in this order from the hot water storage tank 7 to the hot water valve 22. It has been. Further, a bypass path 20 that connects the outlet portion of the sub tank 19 from the three-way valve 18 is provided. Further, an adjustment water channel 10 a is provided between the hot water storage tank 7 and the check valve 14 and the mixing valve 21.

  The flow rate sensor 24 is a sensor that detects the amount of hot water flowing through the hot water supply passage 11. The auxiliary heat source device 17 is a heater that heats the hot water when the temperature of the hot water in the hot water supply channel 11 is low. The BU thermistor 25 is a temperature sensor that detects the temperature of hot water led out from the auxiliary heat source device 17.

  The three-way valve 18 is a valve that switches the flow path of hot water flowing from the upstream hot water supply path 11 to either the downstream hot water supply path 11 side (sub tank 19 side) or the bypass path 20 side. The mixing valve 21 adjusts the temperature by mixing the hot water flowing in from the upstream hot water supply passage 11 and the water flowing in from the adjustment water passage 10a at a set mixing ratio, and mixes the hot water into the downstream hot water supply passage. 11 is a valve that conducts water. The hot water thermistor 26 is a temperature sensor that detects the temperature of hot water downstream of the mixing valve 21.

  In addition, a pressure relief passage 15 branched from the hot water supply passage 11 is provided in the vicinity of the upper portion of the hot water storage tank 7, and a relief valve 16 is provided in the pressure relief passage 15. When the inside of the hot water storage tank 7 is in an overpressure state, the relief valve 16 is opened, warm water is passed through the pressure release passage 15, and the pressure is released.

  The controller 28 controls the sterilization operation of the hot water storage type hot water supply apparatus 1. FIG. 2 is a block diagram showing a functional configuration of the controller 28 of FIG.

In the controller 28, the hot water temperatures Θ _{t1 to} Θ _t4 in the tank detected by the tank temperature sensors 23 a to 23 d, the flow rate F of the hot water supply path 11 detected by the flow rate sensor 24, and the downstream of the auxiliary heat source device 17 detected by the BU thermistor 25. The temperature Θ ₁ of the hot water in the hot water supply passage 11 on the side and the temperature Θ _m of the hot water in the hot water supply passage 11 on the downstream side of the mixing valve 21 detected by the hot water thermistor 26 are input. Further, the controller 28 controls the operation amounts of the output of the auxiliary heat source device 17, the switching direction of the three-way valve 18, and the mixing ratio of the mixing valve 21 based on these input parameters.

  The controller 28 includes a timer 31, a usage amount accumulation unit 32, a usage amount storage unit 33, a sterilization processing determination unit 34, and a sterilization processing unit 35. The timer 31 measures the current time. The usage amount integrating unit 32 integrates the flow rate of the hot water detected by the flow rate sensor 24 every unit time and stores it in the usage amount storage unit 33. The usage amount storage unit 33 is a memory that stores the usage amount of hot water in the hot water storage tank 7 per unit time before the current time.

  The sterilization process determination unit 34 determines whether or not a sterilization process needs to be performed. The sterilization processing unit 35 controls the auxiliary heat source 17, the three-way valve 18, and the mixing valve 21 related to the sterilization processing based on the determination of the sterilization processing determination unit 34.

  The operation of the hot water storage type hot water supply apparatus 1 according to the first embodiment configured as described above will be described below.

  First, the operation of the usage amount integrating unit 32 will be described. When the user performs hot water supply or hot water filling, when the hot water in the hot water storage tank 7 is used, the hot water flows through the hot water supply passage 11. The flow rate of this hot water is detected by the flow rate sensor 24. The usage amount integrating unit 32 integrates the flow rate of the hot water detected by the flow rate sensor 24 every unit time and stores it in the usage amount storage unit 33.

  Thus, the usage amount storage unit 33 stores the usage amount of the hot water in the hot water storage tank 7 for each unit time before the current time as a table such as (Table 1).

  Next, the operation of the sterilization processing determination unit 34 will be described. FIG. 3 is a flowchart showing the operation of the sterilization processing determination unit 34.

  (1) First, in step S1, when the hot water storage hot water supply device 1 is turned on, the controller 28 initializes the operation state to the normal state.

  In the normal state, the sterilization processing unit 35 sets the three-way valve 18 to the bypass path 20 side. Thereby, the hot water in the hot water storage tank 7 flows from the auxiliary heat source 17 and the three-way valve 18 to the mixing valve 21 through the bypass 20.

  (2) Next, in step S2, the controller 28 monitors whether or not the hot water is started. When the user gives an instruction to start filling the bathtub with a remote controller (not shown) or the user operates the hot water tap to start hot water supply, the controller 28 receives a signal from the remote controller or the flow sensor 24. Is detected from the hot water storage tank 7 based on the signal from.

  (3) When hot water is detected, in step S3, the sterilization processing determination unit 34 determines whether or not the current operation state is a normal state. If the operation state is the normal state, the process proceeds to step S4. If not (in the sterilization process state), the process proceeds to step S6.

(4) When the operation state is the normal state, in step S4, the sterilization processing determination unit 34 reads the amount of hot water used in each unit time during the period T1 before the current time from the usage amount storage unit 33. Then, an integrated value Q of the hot water amount in the period T1 (hereinafter referred to as “used hot water amount Q”) is calculated. When using hot water Q is greater than the threshold Q ₁ is, the process proceeds to step S9, in the case of using hot water Q is the threshold Q ₁ or less, the process proceeds to step S5. Here, the threshold Q ₁ is a reference value determines whether the hot-water tank 7 hot water is retained long from use hot water Q in the period T1, a reference for determining whether the sterilization process must Amount.

In the case of Q ≦ Q ₁ in step S5, sterilized for hot water staying a long time in the hot water storage tank 7 is determined to be necessary, the operating state of the sterilization process determining section 34 the controller 28 to the sterilization conditions change, after setting the sterilization start time t _m the current time, the process proceeds to step S9.

  In the sterilization processing state, the sterilization processing unit 35 sets the three-way valve 18 on the sub tank 19 side, ignites the auxiliary heat source device 17, and sets the temperature of the hot water in the hot water supply path 11 at the outlet of the auxiliary heat source device 17 to the sterilization temperature. Θs (for example, 70 ° C.) or more. Thereby, the temperature of the hot water in the hot water supply path 11 from the auxiliary heat source device 17 to the mixing valve 21 becomes equal to or higher than the sterilization temperature Θs. The capacity of the sub tank 19 is designed to be sufficiently large so that the time required for hot water to reach the mixing valve 21 from the auxiliary heat source device 17 is equal to or longer than the sterilization time Tp. Therefore, since the warm water in the hot water supply channel 11 is set to the sterilization temperature Θs or more for a time longer than the sterilization time Tp, the warm water is completely sterilized.

(5) On the other hand, if in step S3 is the operating state of the controller 28 determines that the sterilization conditions, in step S6, the sterilization process determination unit 34 of the time zone to the current time t from the sterilization start time t _m The amount of hot water used in each unit time is read from the usage amount storage unit 33. Then, by adding them, an integrated value Q ′ (hereinafter referred to as “sterilized hot water amount Q ′”) of the sterilization treatment period is calculated. When the amount of sterilized hot water Q ′ is equal to or less than the predetermined threshold value Q ₁ ′, the process proceeds to step S9 in order to continue the sterilization state. Here, the threshold value Q ₁ ′ is a value for determining whether or not all the hot water staying in the hot water storage tank 7 at the sterilization processing start time t _m has been replaced by the present time.

If sterile hot water Q 'is the threshold Q _1' is greater than, or in step S7, the sterilization process determining section 34, using hot water Q used for each unit time during the current previous period T1 is greater than the threshold Q ₁ Determine whether or not. When using hot water Q is the threshold Q ₁ or less, in order to continue a sterilizing process conditions, the process proceeds to step S9.

When using hot water Q is greater than the threshold Q _1, sterilized determination unit 34 changes the operation state of the controller 28 to the normal state, the process proceeds to step S9. Thereby, the sterilization processing operation by the sterilization processing unit 35 is completed.

  (6) In step S9, the controller 28 determines whether or not the hot water is stopped. If the hot water is continued, the process returns to step S3, and if the hot water is stopped, the process returns to step S2.

  With the above operation, in a normal state where sterilization is not required, hot water in the hot water storage tank 7 flows from the three-way valve 18 to the mixing valve 21 via the bypass 20. Therefore, the time until the hot water from the hot water storage tank 7 to the mixing valve 21 reaches is short. Therefore, the hot water in the hot water storage tank 7 can be used in a short time.

  On the other hand, in the sterilization state where sterilization is required, the hot water in the hot water storage tank 7 flows from the three-way valve 18 through the sub tank 19 to the mixing valve 21. Therefore, it takes a long time for the hot water from the hot water storage tank 7 to reach the mixing valve 21. Therefore, it is possible to ensure the time until the hot water reaches the mixing valve 21 from the outlet of the auxiliary heat source device 17 for the required sterilization time Tp or more. Then, the temperature of the hot water is set to be equal to or higher than the sterilization temperature Θs by the auxiliary heat source device 17 so that the hot water led out from the hot water storage tank 7 is maintained at the sterilization temperature Θs or higher and required for the sterilization time Tp or longer. Can be adjusted to temperature. Therefore, energy loss due to heat dissipation can be reduced compared with the case where the entire hot water in the hot water storage tank 7 is heated to the sterilization temperature or higher, and the energy saving performance of the entire system can be improved. Further, since the sterilization process is performed when the hot water in the hot water storage tank 7 is used, there is no period during which hot water supply or hot water filling cannot be performed due to the sterilization process.

Furthermore, criteria for transition from the normal state to the sterilization conditions, using hot water Q in past periods T ₁ is due to whether a threshold value Q ₁ or less. By setting the threshold value Q ₁ to the appropriate value, it can be determined whether the accumulated hot water for a long time in the hot water storage tank 7, it is possible to perform an accurate sterilization.

On the other hand, the criterion of transition from sterilization state to the normal state, sterilization after addition to criterion of whether greater use hot water Q threshold to Q ₁ prior periods T _1, proceeds to the sterilization state quantity of water A criterion for determining whether Q ′ is larger than the threshold value Q ₁ ′ is used. By setting the threshold value Q ₁ ′ to an appropriate value, it is possible to return to the normal state after all of the hot water that has accumulated in the hot water storage tank 7 and needs to be sterilized has been reliably replaced.

  Finally, a design example of the hot water storage type hot water supply apparatus 1 of this embodiment will be described.

(Example 1)
The capacity of the hot water storage tank 7 is 200 L (liters). The sterilization temperature Θs of Legionella is 70 ° C., and the necessary sterilization time Tp is 5 seconds. V = V _sub + V _path (where V _sub is the volume of the _sub tank, and V _path is the flow path volume other than the sub tank) is the total volume of the hot water flow path from the outlet of the auxiliary heat source 17 to the mixing valve 21 via the sub tank 19. To do. Further, the maximum flow rate of the hot water supply channel 11 is set to F _max .

At this time, the threshold Q ₁ is 200 L, the threshold Q ₁ ′ is 200 L, and the sub tank volume V _sub is V _sub [L] = 5 [seconds] × F _max [L / second] −V _path [L].
To design.
(End of example)

  FIG. 4 is a flowchart showing the control operation of the sterilization processing unit 35 of the hot water storage type hot water supply apparatus 1 according to Embodiment 2 of the present invention. In addition, about the structure of the hot water storage type hot water supply apparatus 1 except the operation | movement of the sterilization process part 35, it shall be the same as that of Example 1. FIG.

  In the hot water storage type hot water supply apparatus 1 according to the second embodiment, the sterilization processing unit 35 performs the following operation.

  (1) First, in step S11, the sterilization processing unit 35 determines whether or not the operation state of the controller 28 is a normal state. In the normal state, the process proceeds to the next step S12, and in the sterilization process state, the process proceeds to step S14.

  (2) In step S12, the sterilization processing unit 35 determines whether or not hot water filling is currently instructed by a remote controller or the like. If hot water filling is instructed, the process proceeds to step S16, and if other than hot water filling, the process proceeds to the next step S13.

  (3) In step S13, the sterilization processing unit 35 sets the three-way valve 18 on the bypass path 20 side. Then, the process returns to step S11.

  (4) In step S <b> 14, the sterilization processing unit 35 refers to the detection value of the flow sensor 24 and determines whether hot water is currently being discharged. When the hot water is being discharged, the operation of heating the warm water to the sterilization temperature Θs is performed by the auxiliary heat source device 17 in step S15. Then, the process proceeds to step S16.

  (5) In step S16, the sterilization processing unit 35 sets the three-way valve 18 on the sub tank 19 side. Then, the process returns to step S11.

  By the operation as described above, the sterilization processing unit 35 sets the flow path of the hot water on the sub tank 19 side regardless of whether or not the sterilization processing state is instructed when the hot water filling is instructed by a remote controller or the like. Is done. Usually, in hot water filling, a large amount of hot water in the hot water storage tank 7 is continuously used to fill the bathtub. When filling the hot water, even if it takes some time until the hot water in the hot water storage tank 7 can be used after the start of the hot water, it is not a problem.

  Therefore, the hot water in the hot water storage tank 7 is always discharged through the sub tank 19 when the hot water is filled, so that the water in the sub tank 19 is completely replaced every time the hot water is filled. Therefore, it is possible to prevent water from staying in the sub tank 19 for a long period of time, and it is possible to prevent the generation and increase of Legionella bacteria and other germs in the sub tank 19.

  FIG. 5 is a flowchart showing a control operation of the sterilization processing unit 35 of the hot water storage type hot water supply apparatus 1 according to Embodiment 3 of the present invention. In addition, about the structure of the hot water storage type hot water supply apparatus 1 except the operation | movement of the sterilization process part 35, it shall be the same as that of Example 1. FIG.

  In the hot water storage type hot water supply apparatus 1 according to the third embodiment, the sterilization processing unit 35 performs the following operation.

  (1) First, in step S <b> 21, the sterilization processing unit 35 refers to the detection value of the flow sensor 24 and determines whether hot water is currently being discharged. When the hot water is not being performed, the process waits as it is, and when the hot water is being performed, the process proceeds to the next step S22.

  (2) Next, in step S22, the sterilization processing unit 35 determines whether or not the operation state of the controller 28 is a normal state. In the normal state, the process proceeds to the next step S23, and in the sterilization process state, the process proceeds to step S25.

  (3) In step S23, the sterilization processing unit 35 determines whether hot water filling is currently instructed by a remote controller or the like. If hot water filling is instructed, the process proceeds to step S27, and if not hot water filling, the process proceeds to the next step S24.

  (4) In step S24, the sterilization processing unit 35 sets the three-way valve 18 on the bypass path 20 side. Then, the process returns to step S22. Thereby, when hot water is supplied in a normal state, hot water in the hot water storage tank 7 is discharged through the bypass 20.

(5) On the other hand, in step S25, the sterilization processing unit 35 performs an operation of heating the warm water to the sterilization temperature Θs by the auxiliary heat source device 17. In step S26, the sterilization processing unit 35 adjusts the mixing valve 21, and sets the flow rate F of hot water guided from the auxiliary heat source device 17 to the mixing valve 21 to the maximum flow rate F _max represented by F _max = V / Tp. Adjust so that: Here, V = V _sub + V _path (V _sub is the volume of the _sub- tank, V _path is the volume of the channel other than the sub-tank) is the temperature of the hot water channel from the outlet of the auxiliary heat source 17 to the mixing valve 21 via the sub-tank 19. Total volume. Tp is the required sterilization time. Then, the process proceeds to step S26.

  (6) In step S27, the sterilization processing unit 35 sets the three-way valve 18 to the sub tank 19 side. Then, the process returns to step S22.

  By the operation as described above, the sterilization processing unit 35, as in the case of the second embodiment, when hot water filling is currently instructed by a remote controller or the like, regardless of whether or not it is in the sterilization processing state, The flow path is set on the sub tank 19 side. Therefore, it is possible to prevent water from staying in the sub tank 19 for a long period of time, and it is possible to prevent the generation and increase of Legionella bacteria and other germs in the sub tank 19.

In the case of the sterilization state, the auxiliary heat source 17 heats the hot water flowing through the hot water supply path 11 to a temperature equal to or higher than the sterilization temperature Θs, and the hot water is maintained at the sterilization temperature Θs or higher for a time equal to or longer than the necessary sterilization time Tp. . In this embodiment, in the sterilization state, the amount of hot water discharged from the hot water storage tank 7 is limited to the maximum flow rate F _max or less. Therefore, it is always guaranteed that the hot water is maintained at the sterilization temperature Θs or more for a time longer than the necessary sterilization time Tp.

(Example 2)
The capacity of the hot water storage tank 7 is 200L. The sterilization temperature Θs of Legionella is 70 ° C., and the necessary sterilization time Tp is 5 seconds. The total volume V of the hot water flow path from the outlet of the auxiliary heat source device 17 to the mixing valve 21 via the sub tank 19 is set to 1.0 L.

At this time, the threshold value Q ₁ is 200 L, the threshold value Q ₁ ′ is 200 L, and the maximum flow rate F _max is Fmax [L / second] = V [L] / 5 [second] = 0.2 [L / second].
To design.
(End of example)

In the present embodiment, the mixing valve 21 is used to limit the amount of hot water discharged from the hot water storage tank 7 to the maximum flow rate F _max or less. However, the sub tank 19 and the mixing valve 21 are separated from the mixing valve. It is good also as a structure which provides a flow control valve in between and restrict _| limits the amount of hot water discharged from the hot water storage tank 7 to below the maximum flow _Fmax with this flow control valve.

It is a figure showing the whole structure of the hot water storage type hot-water supply apparatus which concerns on Example 1 of this invention. FIG. 2 is a block diagram illustrating a functional configuration of a controller 28 in FIG. 1. 4 is a flowchart showing the operation of a sterilization processing determination unit 34. It is a flowchart showing the control operation | movement of the sterilization process part 35 of the hot water storage type hot-water supply apparatus 1 which concerns on Example 2 of this invention. It is a flowchart showing the control operation | movement of the sterilization process part 35 of the hot water storage type hot-water supply apparatus 1 which concerns on Example 3 of this invention. It is a figure showing the structure of the conventional hot water storage type hot water supply apparatus described in Patent Document 1.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Hot water storage type hot water supply apparatus 2 Combined heat and power supply apparatus 3 Waste heat circulation path 4 Cooling water circulation pump 5 Circulation heating circuit 6 Exhaust heat exchanger 7 Hot water storage tank 8 Hot water tap 9 Bathtub 10 Supply water path 10a Adjustment water path 11 Hot water supply paths 11a, 11b Branch hot water supply Path 12 Pressure reducing valve 14 Check valve 15 Pressure release path 16 Relief valve 17 Auxiliary heat source 18 Three-way valve 19 Sub tank 20 Bypass path 21 Mixing valve 22 Hot-water valve 23a-23d Tank temperature sensor 24 Flow sensor 25 BU thermistor 26 Hot water thermistor 27 Tank water circulation pump 28 Controller 31 Timer 32 Usage amount accumulating unit 33 Usage amount storage unit 34 Sterilization processing determination unit 35 Sterilization processing unit

Claims (4)

A hot water storage tank for storing hot water;
A water supply channel for supplying water to the hot water storage tank;
An exhaust heat circulation path for supplying heat generated in the combined heat and power supply device to the hot water storage tank by circulating the water in the lower portion of the hot water storage tank to a combined heat and power generation device that generates heat and electric power and returning it to the upper portion of the hot water storage tank; ,
A hot water supply passage leading out hot water inside the hot water storage tank to a hot water tap or bathtub; and
In the hot water storage type hot water supply device equipped with
A flow rate sensor for detecting a flow rate of hot water discharged from the hot water storage tank;
An auxiliary heat source that is provided in the hot water supply path and heats hot water in the hot water supply path;
A first temperature sensor for detecting a temperature Θ1 of hot water in the hot water supply channel downstream of the auxiliary heat source;
A sub tank provided on the downstream side of the auxiliary heat source device of the hot water supply path;
A bypass path provided to form a water path that is connected to the hot water supply path at both ends and bypasses the sub tank;
A three-way valve provided at a branch portion of the hot water supply path and the bypass path on the upstream side of the sub tank, for switching a flow path of hot water led out from the hot water storage tank to the sub tank side or the bypass path;
A controller for controlling the switching of the three-way valve and the operation of the auxiliary heat source device,
The controller is
Usage amount storage means for storing the usage amount of hot water in the hot water storage tank per unit time;
Usage amount integrating means for integrating the flow rate detected by the flow rate sensor per unit time and storing it in the usage amount storage means;
When hot water supply or hot water filling is performed, the amount of hot water in the hot water storage tank for a predetermined period T1 before that time is integrated, and if the integrated value Q is less than or equal to a predetermined threshold value Q1, the operating state is sterilized. An integrated value of the amount of hot water used in the hot water storage tank from the time when the integrated value Q is equal to or greater than a predetermined threshold value Q1 and the operating state is last switched to the sterilized state to the time point. If Q ′ is greater than or equal to a predetermined threshold value Q1 ′, a sterilization process determining means for setting the operating state to a normal state;
When the operation state is the sterilization state, the three-way valve is switched so that the hot water flow path is on the sub-tank side, and the auxiliary heat source is activated to heat the hot water temperature Θ1 to a predetermined sterilization temperature Θs or higher. Sterilization processing means for performing control to switch the three-way valve so that the flow path of the hot water is on the bypass path side when the operation state is a normal state,
A hot water storage type hot water supply apparatus characterized by comprising: With regard to the control for switching the three-way valve, the sterilization means switches the three-way valve so that the hot water flow path is always on the sub-tank side when hot water filling is performed, regardless of the operating state. The hot water storage type hot water supply apparatus according to claim 1, wherein A first flow rate control valve that is provided in the hot water supply path on the downstream side of the sub tank and controls the flow rate of hot water flowing through the hot water supply path;
A flow rate sensor for detecting a flow rate F of hot water flowing through the hot water supply path;
With
When the hot water supply or hot water filling is started and the operation state is a sterilization state, the sterilization means is configured such that the flow rate F detected by the flow rate sensor is changed from the outlet of the auxiliary heat source to the first flow rate control valve. The first flow rate control valve is controlled so that the time during which the hot water passes through the hot water supply path is equal to or less than a flow rate F1 that is a predetermined time Tp required for sterilization. Hot water storage system. An adjustment water channel that connects the sub-tank downstream side of the water supply channel and the hot water supply channel;
A second flow control valve for adjusting a flow rate of water flowing through the adjustment water channel;
A mixing valve that is provided at a connection portion between the adjustment water channel and the hot water supply channel, and adjusts a mixing ratio of hot water from the hot water supply channel and water from the adjustment water channel;
With
The first flow control valve is the mixing valve;
When the hot water supply or hot water filling is started and the operation state is a sterilization state, the sterilization processing means is configured such that the flow rate F detected by the flow rate sensor is from the auxiliary heat source outlet to the flow rate control valve. The mixing valve and the second flow control valve are set so that the time during which the warm water passes through the passage is equal to or less than the flow rate F1, which is a predetermined time Tp required for sterilization, and the hot water temperature discharged is a predetermined set temperature. The hot water storage type hot water supply device according to claim 3, wherein the hot water storage device is controlled.

Images